Solar photocatalytic disinfection with immobilised TiO(2) at pilot-plant scale.

PubMed

Sordo, Carlos; Van Grieken, Rafael; Marugán, Javier; Fernández-Ibáñez, Pilar

2010-01-01

The photocatalytic disinfection efficiency has been investigated for two immobilized TiO(2) catalytic systems (wall reactor and fixed-bed reactor) in a solar pilot plant. Their performances have been compared with the use of a slurry reactor and the solar disinfection without catalyst. The use of photocatalytic TiO(2) wall reactors does no show clear benefits over the solar disinfection process in the absence of catalyst. The reason is that the efficiency of the solar disinfection is so high that the presence of titania in the reactor wall reduces the global efficiency due to the competition for the absorption of photons. As expected, the maximum efficiency was shown by the slurry TiO(2) reactor, due to the optimum contact between bacteria and catalyst. However, it is noticeable that the use of the fixed-bed reactor leads to inactivation rate quite close to that of the slurry, requiring comparable accumulated solar energy of about 6 kJ L(-1) to achieve a 6-log decrease in the concentration of viable bacteria and allowing a total disinfection of the water (below the detection limit of 1 CFU mL(-1)). Not only the high titania surface area of this configuration is responsible for the bacteria inactivation but the important contribution of the mechanical stress has to be considered. The main advantage of the fixed-bed TiO(2) catalyst is the outstanding stability, without deactivation effects after ten reaction cycles, being readily applicable for continuous water treatment systems.

Investigation of the characteristics of a compact steam reformer integrated with a water-gas shift reactor

NASA Astrophysics Data System (ADS)

Seo, Yong-Seog; Seo, Dong-Joo; Seo, Yu-Taek; Yoon, Wang-Lai

The objective of this study is to investigate numerically a compact steam methane reforming (SMR) system integrated with a water-gas shift (WGS) reactor. Separate numerical models are established for the combustion part, SMR and WGS reaction bed. The concentration of species at the exits of the SMR and WGS bed, and the temperatures in the WGS bed are in good agreement with the measured data. Heat transfer to the catalyst beds and the catalytic reactions in the SMR and WGS catalyst bed are investigated as a function of the operation parameters. The conversion of methane at the exit of the SMR catalyst bed is calculated to be 87%, and the carbon monoxide concentration at the outlet of the WGS bed is estimated to be 0.45%. The effects of the cooling heat flux at the outside wall of the system and steam-to-carbon (S/C) ratio are also examined. As the cooling heat flux increases, both the methane conversion and carbon monoxide content are reduced in the SMR bed, and the carbon monoxide conversion is improved in the WGS bed. Both methane conversion and carbon dioxide reduction increase with increasing steam-to-carbon ratio.

Deactivation of Zeolite Catalyst H-ZSM-5 during Conversion of Methanol to Gasoline: Operando Time- and Space-Resolved X-ray Diffraction.

PubMed

Rojo-Gama, Daniel; Mentel, Lukasz; Kalantzopoulos, Georgios N; Pappas, Dimitrios K; Dovgaliuk, Iurii; Olsbye, Unni; Lillerud, Karl Petter; Beato, Pablo; Lundegaard, Lars F; Wragg, David S; Svelle, Stian

2018-03-15

The deactivation of zeolite catalyst H-ZSM-5 by coking during the conversion of methanol to hydrocarbons was monitored by high-energy space- and time-resolved operando X-ray diffraction (XRD) . Space resolution was achieved by continuous scanning along the axial length of a capillary fixed bed reactor with a time resolution of 10 s per scan. Using real structural parameters obtained from XRD, we can track the development of coke at different points in the reactor and link this to a kinetic model to correlate catalyst deactivation with structural changes occurring in the material. The "burning cigar" model of catalyst bed deactivation is directly observed in real time.

Fischer-Tropsch synthesis from a low H/sub 2/:CO gas in a dry fluidized-bed system. Volume 2. Development of microreactor systems for unsteady-state Fischer-Tropsch synthesis. Final technical report. [408 references

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whiting, G.K.; Liu, Y.A.; Squires, A.M.

1986-10-01

Vibrofluidized microreactor systems have been developed for studies of unsteady-state Fischer-Tropsch synthesis. This development is aimed at preventing carbon deposition on a fused-iron catalyst in a novel reactor called the ''heat tray.'' This reactor involves a supernatant gas flowing over a shallow fluidized bed of catalyst particles. Three systems were built: (1) a vibrofluidized-bed microreactor system for obtaining baseline carbon deposition information under industrially important reaction conditions; (2) a sliding-plug vibrofluidized-bed microreactor system for rapid switching of feed gases in the F-T synthesis; and (3) a cold-flow microreactor model for studying the gas mixing characteristics of the sliding-plug vibrofluidized-bed microreactor.more » The results show that catalyst defluidization occurred under steady-state synthesis conditions below 395 C using a feed gas of H/sub 2//CO ratio of 2:1 or less. Above 395 C, the probability of hydrocarbon chain growth (..cap alpha.. < 0.50 to prevent accumulation of high-molecular-weight species that cause defluidization. Carbon deposition was rapid above 395 C when a feed gas of H/sub 2//CO ratio of 2:1 or less was used. Cold-flow microreactor model studies show that rapid (on the order of seconds), quantitative switching of feed gases over a vibrofluidized bed of catalyst could be achieved. Vibrofluidization of the catalyst bed induced little backmixing of feed gas over the investigated flow-rate range of 417 to 1650 actual mm/sup 3//s. Further, cold-flow microreactor model studies showed intense solid mixing when a bed of fused-iron catalyst (150 to 300 microns) was vibrofluidized at 24 cycles per second with a peak-to-peak amplitude of 4 mm. The development of the microreactor systems provided an easy way of accurately determining integral fluid-bed kinetics in a laboratory reactor. 408 refs., 156 figs., 27 tabs.« less

Technology development for cobalt F-T catalysts. Quarterly technical progress report number 10, January 1--March 31, 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singleton, A.H.

1995-06-28

The goal of this project is the development of a commercially-viable, cobalt-based Fischer-Tropsch (F-T) catalyst for use in a slurry bubble column reactor. The major objectives of this work are (1) to develop a cobalt-based F-T catalyst with low (< 5%) methane selectivity, (2) to develop a cobalt-based F-T catalyst with water-gas shift activity, and (3) to combine both these improvements into one catalyst. The project consists of five major tasks: catalyst development; catalyst testing; catalyst reproducibility tests; catalyst aging tests; and preliminary design and cost estimate for a demonstrate scale catalyst production facility. Technical accomplishments during this reporting periodmore » include the following. It appears that the higher activity obtained for the catalysts prepared using an organic solution and reduced directly without prior calcination was the result of higher dispersions obtained under such pretreatment. A Ru-promoted Co catalyst on alumina with 30% Co loading exhibited a 4-fold increase in dispersion and a 2-fold increase in activity in the fixed-bed reactor from that obtained with the non-promoted catalyst. Several reactor runs have again focused on pushing conversion to higher levels. The maximum conversion obtained has been 49.7% with 26g catalyst. Further investigations of the effect of reaction temperature on the performance of Co catalysts during F-T synthesis were started using a low activity catalyst and one of the most active catalysts. The three 1 kg catalyst batches prepared by Calsicat for the reproducibility and aging studies were tested in both the fixed-bed and slurry bubble column reactors under the standard reaction conditions. The effects of adding various promoters to some cobalt catalysts have also been addressed. Results are presented and discussed.« less

Performance and life cycle environmental benefits of recycling spent ion exchange brines by catalytic treatment of nitrate.

PubMed

Choe, Jong Kwon; Bergquist, Allison M; Jeong, Sangjo; Guest, Jeremy S; Werth, Charles J; Strathmann, Timothy J

2015-09-01

Salt used to make brines for regeneration of ion exchange (IX) resins is the dominant economic and environmental liability of IX treatment systems for nitrate-contaminated drinking water sources. To reduce salt usage, the applicability and environmental benefits of using a catalytic reduction technology to treat nitrate in spent IX brines and enable their reuse for IX resin regeneration were evaluated. Hybrid IX/catalyst systems were designed and life cycle assessment of process consumables are used to set performance targets for the catalyst reactor. Nitrate reduction was measured in a typical spent brine (i.e., 5000 mg/L NO3(-) and 70,000 mg/L NaCl) using bimetallic Pd-In hydrogenation catalysts with variable Pd (0.2-2.5 wt%) and In (0.0125-0.25 wt%) loadings on pelletized activated carbon support (Pd-In/C). The highest activity of 50 mgNO3(-)/(min - g(Pd)) was obtained with a 0.5 wt%Pd-0.1 wt%In/C catalyst. Catalyst longevity was demonstrated by observing no decrease in catalyst activity over more than 60 days in a packed-bed reactor. Based on catalyst activity measured in batch and packed-bed reactors, environmental impacts of hybrid IX/catalyst systems were evaluated for both sequencing-batch and continuous-flow packed-bed reactor designs and environmental impacts of the sequencing-batch hybrid system were found to be 38-81% of those of conventional IX. Major environmental impact contributors other than salt consumption include Pd metal, hydrogen (electron donor), and carbon dioxide (pH buffer). Sensitivity of environmental impacts of the sequencing-batch hybrid reactor system to sulfate and bicarbonate anions indicate the hybrid system is more sustainable than conventional IX when influent water contains <80 mg/L sulfate (at any bicarbonate level up to 100 mg/L) or <20 mg/L bicarbonate (at any sulfate level up to 100 mg/L) assuming 15 brine reuse cycles. The study showed that hybrid IX/catalyst reactor systems have potential to reduce resource consumption and improve environmental impacts associated with treating nitrate-contaminated water sources. Copyright © 2015 Elsevier Ltd. All rights reserved.

Integrated reformer and shift reactor

DOEpatents

Bentley, Jeffrey M.; Clawson, Lawrence G.; Mitchell, William L.; Dorson, Matthew H.

2006-06-27

A hydrocarbon fuel reformer for producing diatomic hydrogen gas is disclosed. The reformer includes a first reaction vessel, a shift reactor vessel annularly disposed about the first reaction vessel, including a first shift reactor zone, and a first helical tube disposed within the first shift reactor zone having an inlet end communicating with a water supply source. The water supply source is preferably adapted to supply liquid-phase water to the first helical tube at flow conditions sufficient to ensure discharge of liquid-phase and steam-phase water from an outlet end of the first helical tube. The reformer may further include a first catalyst bed disposed in the first shift reactor zone, having a low-temperature shift catalyst in contact with the first helical tube. The catalyst bed includes a plurality of coil sections disposed in coaxial relation to other coil sections and to the central longitudinal axis of the reformer, each coil section extending between the first and second ends, and each coil section being in direct fluid communication with at least one other coil section.

Process for the preparation of cumene

DOEpatents

Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

1991-01-01

Cumene is produced in a catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 50.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic by feeding propylene to the catalyst bed while benzene is conveniently added through the reflux to result in a molar excess present in the reactor to that required to react with propylene, thereby reacting substantially all of the propylene and recovering benzene as the principal overhead and cumene and diisopropyl benzene in the bottoms. The bottoms are fractionated, the cumene recovered and the bottoms are contacted with benzene in the liquid phase in a fixed bed straight pass reactor under conditions to transalkylate the benzene thereby converting most of the diisopropyl benzene to cumene which is again separated and recovered.

Process for the preparation of cumene

DOEpatents

Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

1991-10-08

Cumene is produced in a catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 50 C to 500 C, using as the catalyst a molecular sieve characterized as acidic by feeding propylene to the catalyst bed while benzene is conveniently added through the reflux to result in a molar excess present in the reactor to that required to react with propylene, thereby reacting substantially all of the propylene and recovering benzene as the principal overhead and cumene and diisopropyl benzene in the bottoms. The bottoms are fractionated, the cumene recovered and the bottoms are contacted with benzene in the liquid phase in a fixed bed straight pass reactor under conditions to transalkylate the benzene thereby converting most of the diisopropyl benzene to cumene which is again separated and recovered. 2 figures.

Process for the preparation of ethyl benzene

DOEpatents

Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

1995-12-19

Ethyl benzene is produced in a catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 50 C to 300 C, using as the catalyst a mole sieve characterized as acidic by feeding ethylene to the catalyst bed while benzene is conveniently added through the reflux to result in a molar excess present in the reactor to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene and diethyl benzene in the bottoms. The bottoms are fractionated, the ethyl benzene recovered and the bottoms are contacted with benzene in the liquid phase in a fixed bed straight pass reactor under conditions to transalkylate the benzene thereby converting most of the diethyl benzene to ethyl benzene which is again separated and recovered. 2 figs.

Process for the preparation of ethyl benzene

DOEpatents

Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

1995-01-01

Ethyl benzene is produced in a catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 50.degree. C. to 300.degree. C., using as the catalyst a mole sieve characterized as acidic by feeding ethylene to the catalyst bed while benzene is conveniently added through the reflux to result in a molar excess present in the reactor to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene and diethyl benzene in the bottoms. The bottoms are fractionated, the ethyl benzene recovered and the bottoms are contacted with benzene in the liquid phase in a fixed bed straight pass reactor under conditions to transalkylate the benzene thereby converting most of the diethyl benzene to ethyl benzene which is again separated and recovered.

Monolithic catalyst beds for hydrazine reactors

NASA Technical Reports Server (NTRS)

1973-01-01

A monolithic catalyst bed for monopropellant hydrazine decomposition was evaluated. The program involved the evaluation of a new hydrazine catalyst concept wherein open-celled foamed materials are used as supports for the active catalysts. A high-surface-area material is deposited upon the open-celled foamed material and is then coated with an active metal to provide a spontaneous catalyst. Only a fraction of the amount of expensive active metal in currently available catalysts is needed to promote monolithic catalyst. Numerous parameters were evaluated during the program, and the importance of additional parameters became obvious only while the program was in progress. A demonstration firing (using a 2.2-Newton (N)(0.5-lbf) reactor) successfully accumulated 7,700 seconds of firing time and 16 ambient temperature starts without degradation. Based on the excellent results obtained throughout the program and the demonstrated life capability of the monolithic foam, it is recommended that additional studies be conducted to further exploit the advantages of this concept.

Conceptual process design and techno-economic assessment of ex situ catalytic fast pyrolysis of biomass: A fixed bed reactor implementation scenario for future feasibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dutta, Abhijit; Schaidle, Joshua A.; Humbird, David

Ex situ catalytic fast pyrolysis of biomass is a promising route for the production of fungible liquid biofuels. There is significant ongoing research on the design and development of catalysts for this process. However, there are a limited number of studies investigating process configurations and their effects on biorefinery economics. Herein we present a conceptual process design with techno-economic assessment; it includes the production of upgraded bio-oil via fixed bed ex situ catalytic fast pyrolysis followed by final hydroprocessing to hydrocarbon fuel blendstocks. This study builds upon previous work using fluidized bed systems, as detailed in a recent design reportmore » led by the National Renewable Energy Laboratory (NREL/TP-5100-62455); overall yields are assumed to be similar, and are based on enabling future feasibility. Assuming similar yields provides a basis for easy comparison and for studying the impacts of areas of focus in this study, namely, fixed bed reactor configurations and their catalyst development requirements, and the impacts of an inline hot gas filter. A comparison with the fluidized bed system shows that there is potential for higher capital costs and lower catalyst costs in the fixed bed system, leading to comparable overall costs. The key catalyst requirement is to enable the effective transformation of highly oxygenated biomass into hydrocarbons products with properties suitable for blending into current fuels. Potential catalyst materials are discussed, along with their suitability for deoxygenation, hydrogenation and C–C coupling chemistry. This chemistry is necessary during pyrolysis vapor upgrading for improved bio-oil quality, which enables efficient downstream hydroprocessing; C–C coupling helps increase the proportion of diesel/jet fuel range product. One potential benefit of fixed bed upgrading over fluidized bed upgrading is catalyst flexibility, providing greater control over chemistry and product composition. Since this study is based on future projections, the impacts of uncertainties in the underlying assumptions are quantified via sensitivity analysis. As a result, this analysis indicates that catalyst researchers should prioritize by: carbon efficiency > catalyst cost > catalyst lifetime, after initially testing for basic operational feasibility.« less

Conceptual process design and techno-economic assessment of ex situ catalytic fast pyrolysis of biomass: A fixed bed reactor implementation scenario for future feasibility

DOE PAGES

Dutta, Abhijit; Schaidle, Joshua A.; Humbird, David; ...

2015-10-06

Ex situ catalytic fast pyrolysis of biomass is a promising route for the production of fungible liquid biofuels. There is significant ongoing research on the design and development of catalysts for this process. However, there are a limited number of studies investigating process configurations and their effects on biorefinery economics. Herein we present a conceptual process design with techno-economic assessment; it includes the production of upgraded bio-oil via fixed bed ex situ catalytic fast pyrolysis followed by final hydroprocessing to hydrocarbon fuel blendstocks. This study builds upon previous work using fluidized bed systems, as detailed in a recent design reportmore » led by the National Renewable Energy Laboratory (NREL/TP-5100-62455); overall yields are assumed to be similar, and are based on enabling future feasibility. Assuming similar yields provides a basis for easy comparison and for studying the impacts of areas of focus in this study, namely, fixed bed reactor configurations and their catalyst development requirements, and the impacts of an inline hot gas filter. A comparison with the fluidized bed system shows that there is potential for higher capital costs and lower catalyst costs in the fixed bed system, leading to comparable overall costs. The key catalyst requirement is to enable the effective transformation of highly oxygenated biomass into hydrocarbons products with properties suitable for blending into current fuels. Potential catalyst materials are discussed, along with their suitability for deoxygenation, hydrogenation and C–C coupling chemistry. This chemistry is necessary during pyrolysis vapor upgrading for improved bio-oil quality, which enables efficient downstream hydroprocessing; C–C coupling helps increase the proportion of diesel/jet fuel range product. One potential benefit of fixed bed upgrading over fluidized bed upgrading is catalyst flexibility, providing greater control over chemistry and product composition. Since this study is based on future projections, the impacts of uncertainties in the underlying assumptions are quantified via sensitivity analysis. As a result, this analysis indicates that catalyst researchers should prioritize by: carbon efficiency > catalyst cost > catalyst lifetime, after initially testing for basic operational feasibility.« less

Partial Oxidation of Hydrocarbons in a Segmented Bed Using Oxide-based Catalysts and Oxygen-conducting Supports

NASA Astrophysics Data System (ADS)

Smith, Mark W.

Two objectives for the catalytic reforming of hydrocarbons to produce synthesis gas are investigated herein: (1) the effect of oxygen-conducting supports with partially substituted mixed-metal oxide catalysts, and (2) a segmented bed approach using different catalyst configurations. Excess carbon deposition was the primary cause of catalyst deactivation, and was the focus of the experiments for both objectives. The formation and characterization of deposited carbon was examined after reaction for one of the selected catalysts to determine the quantity and location of the carbon on the catalyst surface leading to deactivation. A nickel-substituted barium hexaaluminate (BNHA), with the formula BaAl 11.6Ni0.4O18.8, and a Rh-substituted lanthanum zirconate pyrochlore (LCZR) with the formula La1.89Ca0.11 Zr1.89Rh0.11, were combined with two different doped ceria supports. These supports were gadolinium-doped ceria (GDC) and zirconium-doped ceria (ZDC). The active catalyst phases were combined with the supports in different ratios using different synthesis techniques. The catalysts were characterized using several different techniques and were tested under partial oxidation (POX) of n-tetradecane (TD), a diesel fuel surrogate. It was found that the presence of GDC and ZDC reduced the formation of carbon for both catalysts; the optimal ratio of catalyst to support was different for the hexaaluminate and the pyrochlore; a loading of 20 wt% of the pyrochlore with ZDC produced the most stable performance in the presence of common fuel contaminants (>50 h); and, the incipient wetness impregnation synthesis method of applying the active catalyst to the support produced more stable product yields than the catalyst prepared by a solid-state mixing technique. Different hexaaluminate and pyrochlore catalysts were used in different configurations in a segmented bed approach. The first strategy was to promote the indirect reforming mechanism by placing a combustion catalyst in the reactor inlet, followed by a reforming catalyst. This approach demonstrated that BNHA can be used in the reactor inlet to promote combustion with 1 wt% Rh-substituted pyrochlore in the reactor outlet, but the combustion catalyst should fill less than 50% of the reactor. The second approach placed specific catalysts in regions of the reactor that have conditions in which they are less likely to deactivate. This showed the most benefit in the use of a sulfur-tolerant noble metal catalyst in the reactor outlet. The carbon formation study was conducted on a 2 wt% Rh-substituted pyrochlore. POX of TD for various run times, followed by temperature programmed oxidation, revealed two different types of carbon deposits in the catalyst bed: carbon that burned off at relatively low temperature (LTC), and carbon that burned off at higher temperatures (HTC). The LTC reached a steady state level within two hours of reaction, and was determined not to lead to catalyst deactivation. The HTC continued to accumulate with time on stream. A mathematical expression was developed to predict the rate of formation of the HTC for a given set of reaction conditions (O/C = 1.25). This expression was modified from data from a test under different reaction conditions (O/C = 1.1) for one length of time, and was found to predict the carbon formation for a different run time within 3%.

Sustainable production of green feed from carbon dioxide and hydrogen.

PubMed

Landau, Miron V; Vidruk, Roxana; Herskowitz, Moti

2014-03-01

Carbon dioxide hydrogenation to form hydrocarbons was conducted on two iron-based catalysts, prepared according to procedures described in the literature, and on a new iron spinel catalyst. The CO2 conversion measured in a packed-bed reactor was limited to about 60% because of excessive amounts of water produced in this process. Switching to a system of three packed-bed reactors in series with interim removal of water and condensed hydrocarbons increased CO2 conversion to as much as 89%. The pure spinel catalyst displayed a significantly higher activity and selectivity than those of the other iron catalysts. This process produces a product called green feed, which is similar in composition to the product of a high-temperature, iron-based Fischer–Tropsch process from syngas. The green feed can be readily converted into renewable fuels by well-established technologies.

Method of producing pyrolysis gases from carbon-containing materials

DOEpatents

Mudge, Lyle K.; Brown, Michael D.; Wilcox, Wayne A.; Baker, Eddie G.

1989-01-01

A gasification process of improved efficiency is disclosed. A dual bed reactor system is used in which carbon-containing feedstock materials are first treated in a gasification reactor to form pyrolysis gases. The pyrolysis gases are then directed into a catalytic reactor for the destruction of residual tars/oils in the gases. Temperatures are maintained within the catalytic reactor at a level sufficient to crack the tars/oils in the gases, while avoiding thermal breakdown of the catalysts. In order to minimize problems associated with the deposition of carbon-containing materials on the catalysts during cracking, a gaseous oxidizing agent preferably consisting of air, oxygen, steam, and/or mixtures thereof is introduced into the catalytic reactor at a high flow rate in a direction perpendicular to the longitudinal axis of the reactor. This oxidizes any carbon deposits on the catalysts, which would normally cause catalyst deactivation.

Stable carbonous catalyst particles and method for making and utilizing same

DOEpatents

Ganguli, Partha S.; Comolli, Alfred G.

2005-06-14

Stable carbonous catalyst particles composed of an inorganic catalytic metal/metal oxide powder and a carbonaceous binder material are formed having a basic inner substantially uniform-porous carbon coating of the catalytic powder, and may include an outer porous carbon coating layer. Suitable inorganic catalytic powders include zinc-chromite (ZnO/Cr.sub.2 03) and suitable carbonaceous liquid binders having molecular weight of 200-700 include partially polymerized furfuryl alcohol, which are mixed together, shaped and carbonized and partially oxidized at elevated temperature. Such stable carbonous catalyst particles such as 0.020-0.100 inch (0.51-2.54 mm) diameter extrudates, have total carbon content of 2-25 wt. % and improved crush strength of 1.0-5 1b/mn, 50-300 m.sup.2 /g surface area, and can be advantageously utilized in fixed bed or ebullated/fluidized bed reactor operations. This invention also includes method steps for making the stable carbonous catalyst particles having improved particle strength and catalytic activity, and processes for utilizing the active stable carbonous carbon-coated catalysts such as for syn-gas reactions in ebullated/fluidized bed reactors for producing alcohol products and Fischer-Tropsch synthesis liquid products.

Supported transition metal catalysts for para- to ortho-hydrogen conversion

NASA Technical Reports Server (NTRS)

Brooks, Christopher J.; Wang, Wei; Eyman, Darrell P.

1994-01-01

The main goal of this study was to develop and improve on existing catalysts for the conversion of ortho- to para-hydrogen. Starting with a commercially available Air Products nickel silicate, which had a beta value of 20, we were trying to synthesize catalysts that would be an improvement to AP. This was accomplished by preparing silicates with various metals as well as different preparation methods. We also prepared supported ruthenium catalysts by various techniques using several metal precursors to improve present technology. What was also found was that the activation conditions prior to catalytic testing was highly important for both the silicates and the supported ruthenium catalysts. While not the initial focus of the research, we made some interesting observations into the adsorption of H2 on ruthenium. This helped us to get a better understanding of how ortho- to para-H2 conversion takes place, and what features in a catalyst are important to optimize activity. Reactor design was the final area in which some interesting conclusions were drawn. As discussed earlier, the reactor catalyst bed must be constructed using straight 1/8 feet OD stainless steel tubing. It was determined that the use of 1/4 feet OD tubing caused two problems. First, the radius from the center of the bed to the wall was too great for thermal equilibrium. Since the reaction of ortho- to para-H2 is exothermic, the catalyst bed center was warmer than the edges. Second, the catalyst bed was too shallow using a 1/4 feet tube. This caused reactant blow-by which was thought to decrease the measured activity when the flow rate was increased. The 1/8 feet tube corrected both of these concerns.

Hydrogenation of furfural at the dynamic Cu surface of CuOCeO2/Al2O3 in vapor phase packed bed reactor

USDA-ARS?s Scientific Manuscript database

The hydrogenation of furfural to furfuryl alcohol over a CuOCeO2/'-Al2O3 catalyst in a flow reactor is reported. The catalyst was prepared by the wet impregnation of Cu onto a CeO2/'-Al2O3 precursor. The calcined catalyst was then treated with HNO3 to remove surface CuO resulting in a mixed CuCe oxi...

In-situ upgrading of biomass pyrolysis vapors: catalyst screening on a fixed bed reactor.

PubMed

Stefanidis, S D; Kalogiannis, K G; Iliopoulou, E F; Lappas, A A; Pilavachi, P A

2011-09-01

In-situ catalytic upgrading of biomass fast pyrolysis vapors was performed in a fixed bed bench-scale reactor at 500°C, for catalyst screening purposes. The catalytic materials tested include a commercial equilibrium FCC catalyst (E-cat), various commercial ZSM-5 formulations, magnesium oxide and alumina materials with varying specific surface areas, nickel monoxide, zirconia/titania, tetragonal zirconia, titania and silica alumina. The bio-oil was characterized measuring its water content, the carbon-hydrogen-oxygen (by difference) content and the chemical composition of its organic fraction. Each catalytic material displayed different catalytic effects. High surface area alumina catalysts displayed the highest selectivity towards hydrocarbons, yielding however low organic liquid products. Zirconia/titania exhibited good selectivity towards desired compounds, yielding higher organic liquid product than the alumina catalysts. The ZSM-5 formulation with the highest surface area displayed the most balanced performance having a moderate selectivity towards hydrocarbons, reducing undesirable compounds and producing organic liquid products at acceptable yields. Copyright © 2011 Elsevier Ltd. All rights reserved.

Catalytic decomposition of tar derived from wood waste pyrolysis using Indonesian low grade iron ore as catalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wicakso, Doni Rahmat; Chemical Engineering Department, Faculty of Engineering, Gadjah Mada University, Jalan Grafika No. 2 Bulaksumur, Yogyakarta, 55281; Sutijan

Low grade iron ore can be used as an alternative catalyst for bio-tar decomposition. Compared to other catalysts, such as Ni, Rd, Ru, Pd and Pt, iron ore is cheaper. The objective of this research was to investigate the effect of using low grade iron ore as catalyst for tar catalytic decomposition in fixed bed reactor. Tar used in this experiment was pyrolysis product of wood waste while the catalyst was Indonesian low grade iron ore. The variables studied were temperatures between 500 – 600 °C and catalyst weight between 0 – 40 gram. The first step, tar was evaporatedmore » at 450 °C to produce tar vapor. Then, tar vapor was flowed to fixed bed reactor filled low grade iron ore. Gas and tar vapor from reactor was cooled, then the liquid and uncondensable gas were analyzed by GC/MS. The catalyst, after experiment, was weighed to calculate total carbon deposited into catalyst pores. The results showed that the tar components that were heavy and light hydrocarbon were decomposed and cracked within the iron ore pores to from gases, light hydrocarbon (bio-oil) and carbon, thus decreasing content tar in bio-oil and increasing the total gas product. In conclusion, the more low grade iron ore used as catalyst, the tar content in the liquid decrease, the H{sup 2} productivity increased and calorimetric value of bio-oil increased.« less

Catalytic wet air oxidation of coke-plant wastewater on ruthenium-based eggshell catalysts in a bubbling bed reactor.

PubMed

Yang, M; Sun, Y; Xu, A H; Lu, X Y; Du, H Z; Sun, C L; Li, C

2007-07-01

Catalytic wet air of coke-plant wastewater was studied in a bubbling bed reactor. Two types of supported Ru-based catalysts, eggshell and uniform catalysts, were employed. Compared with the results in the wet air oxidation of coke-plant wastewater, supported Ru uniform catalysts showed high activity for chemical oxygen demand (COD) and ammonia/ammonium compounds (NH3-N) removal at temperature of 250 degrees C and pressure of 4.8 MPa, and it has been demonstrated that the catalytic activity of uniform catalyst depended strongly on the distribution of active sites of Ru on catalyst. Compared to the corresponding uniform catalysts with the same Ru loading (0.25 wt.% and 0.1 wt.%, respectively), the eggshell catalysts showed higher activities for CODcr removal and much higher activities for NH3-N degradation. The high activity of eggshell catalyst for treatment of coke-plant wastewater can be attributed to the higher density of active Ru sites in the shell layer than that of the corresponding uniform catalyst with the same Ru loading. It has been also evidenced that the active Ru sites in the internal core of uniform catalyst have very little or no contribution to CODcr and NH3-N removal in the total oxidation of coke-plant wastewater.

Remediation of trichloroethylene by bio-precipitated and encapsulated palladium nanoparticles in a fixed bed reactor.

PubMed

Hennebel, Tom; Verhagen, Pieter; Simoen, Henri; De Gusseme, Bart; Vlaeminck, Siegfried E; Boon, Nico; Verstraete, Willy

2009-08-01

Trichloroethylene is a toxic and recalcitrant groundwater pollutant. Palladium nanoparticles bio-precipitated on Shewanella oneidensis were encapsulated in polyurethane, polyacrylamide, alginate, silica or coated on zeolites. The reactivity of these bio-Pd beads and zeolites was tested in batch experiments and trichloroethylene dechlorination followed first order reaction kinetics. The calculated k-values of the encapsulated catalysts were a factor of six lower compared to non-encapsulated bio-Pd. Bio-Pd, used as a catalyst, was able to dechlorinate 100 mgL(-1) trichloroethylene within a time period of 1h. The main reaction product was ethane; yet small levels of chlorinated intermediates were detected. Subsequently polyurethane cubes empowered with bio-Pd were implemented in a fixed bed reactor for the treatment of water containing trichloroethylene. The influent recycle configuration resulted in a cumulative removal of 98% after 22 h. The same reactor in a flow through configuration achieved removal rates up to 1059 mg trichloroethylene g Pd(-1)d(-1). This work showed that fixed bed reactors with bio-Pd polyurethane cubes can be instrumental for remediation of water contaminated with trichloroethylene.

Conversion of NO with a catalytic packed-bed dielectric barrier discharge reactor

NASA Astrophysics Data System (ADS)

Xu, CAO; Weixuan, ZHAO; Renxi, ZHANG; Huiqi, HOU; Shanping, CHEN; Ruina, ZHANG

2017-11-01

This paper discusses the conversion of nitric oxide (NO) with a low-temperature plasma induced by a catalytic packed-bed dielectric barrier discharge (DBD) reactor. Alumina oxide (Al2O3), glass (SiO2) and zirconium oxide (ZrO2), three different spherical packed materials of the same size, were each present in the DBD reactor. The NO conversion under varying input voltage and specific energy density, and the effects of catalysts (titanium dioxide (TiO2) and manganese oxide (MnO x ) coated on Al2O3) on NO conversion were investigated. The experimental results showed that NO conversion was greatly enhanced in the presence of packed materials in the reactor, and the catalytic packed bed of MnO x /Al2O3 showed better performance than that of TiO2/Al2O3. The surface and crystal structures of the materials and catalysts were characterized through scanning electron microscopy analysis. The final products were clearly observed by a Fourier transform infrared spectrometer and provided a better understanding of NO conversion.

In Situ and ex Situ Catalytic Pyrolysis of Pine in a Bench-Scale Fluidized Bed Reactor System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iisa, Kristiina; French, Richard J.; Orton, Kellene A.

In situ and ex situ catalytic pyrolysis were compared in a system with two 2-in. bubbling fluidized bed reactors. Pine was pyrolyzed in the system with a catalyst, HZSM-5 with a silica-to-alumina ratio of 30, placed either in the first (pyrolysis) reactor or the second (upgrading) reactor. Both the pyrolysis and upgrading temperatures were 500 degrees C, and the weight hourly space velocity was 1.1 h -1. Five catalytic cycles were completed in each experiment. The catalytic cycles were continued until oxygenates in the vapors became dominant. The catalyst was then oxidized, after which a new catalytic cycle was begun.more » The in situ configuration gave slightly higher oil yield but also higher oxygen content than the ex situ configuration, which indicates that the catalyst deactivated faster in the in situ configuration than the ex situ configuration. Analysis of the spent catalysts confirmed higher accumulation of metals in the in situ experiment. In all experiments, the organic oil mass yields varied between 14 and 17% and the carbon efficiencies between 20 and 25%. The organic oxygen concentrations in the oils were 16-18%, which represented a 45% reduction compared to corresponding noncatalytic pyrolysis oils prepared in the same fluidized bed reactor system. GC/MS analysis showed the oils to contain one- to four-ring aromatic hydrocarbons and a variety of oxygenates (phenols, furans, benzofurans, methoxyphenols, naphthalenols, indenols). Lastly, high fractions of oxygen were rejected as water, CO, and CO 2, which indicates the importance of dehydration, decarbonylation, and decarboxylation reactions. Light gases were the major sources of carbon losses, followed by char and coke.« less

In Situ and ex Situ Catalytic Pyrolysis of Pine in a Bench-Scale Fluidized Bed Reactor System

DOE PAGES

Iisa, Kristiina; French, Richard J.; Orton, Kellene A.; ...

2016-02-03

In situ and ex situ catalytic pyrolysis were compared in a system with two 2-in. bubbling fluidized bed reactors. Pine was pyrolyzed in the system with a catalyst, HZSM-5 with a silica-to-alumina ratio of 30, placed either in the first (pyrolysis) reactor or the second (upgrading) reactor. Both the pyrolysis and upgrading temperatures were 500 degrees C, and the weight hourly space velocity was 1.1 h -1. Five catalytic cycles were completed in each experiment. The catalytic cycles were continued until oxygenates in the vapors became dominant. The catalyst was then oxidized, after which a new catalytic cycle was begun.more » The in situ configuration gave slightly higher oil yield but also higher oxygen content than the ex situ configuration, which indicates that the catalyst deactivated faster in the in situ configuration than the ex situ configuration. Analysis of the spent catalysts confirmed higher accumulation of metals in the in situ experiment. In all experiments, the organic oil mass yields varied between 14 and 17% and the carbon efficiencies between 20 and 25%. The organic oxygen concentrations in the oils were 16-18%, which represented a 45% reduction compared to corresponding noncatalytic pyrolysis oils prepared in the same fluidized bed reactor system. GC/MS analysis showed the oils to contain one- to four-ring aromatic hydrocarbons and a variety of oxygenates (phenols, furans, benzofurans, methoxyphenols, naphthalenols, indenols). Lastly, high fractions of oxygen were rejected as water, CO, and CO 2, which indicates the importance of dehydration, decarbonylation, and decarboxylation reactions. Light gases were the major sources of carbon losses, followed by char and coke.« less

Continuous Heterogeneous Photocatalysis in Serial Micro-Batch Reactors.

PubMed

Pieber, Bartholomäus; Shalom, Menny; Antonietti, Markus; Seeberger, Peter H; Gilmore, Kerry

2018-01-29

Solid reagents, leaching catalysts, and heterogeneous photocatalysts are commonly employed in batch processes but are ill-suited for continuous-flow chemistry. Heterogeneous catalysts for thermal reactions are typically used in packed-bed reactors, which cannot be penetrated by light and thus are not suitable for photocatalytic reactions involving solids. We demonstrate that serial micro-batch reactors (SMBRs) allow for the continuous utilization of solid materials together with liquids and gases in flow. This technology was utilized to develop selective and efficient fluorination reactions using a modified graphitic carbon nitride heterogeneous catalyst instead of costly homogeneous metal polypyridyl complexes. The merger of this inexpensive, recyclable catalyst and the SMBR approach enables sustainable and scalable photocatalysis. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of attrition test methods: ASTM standard fluidized bed vs jet cup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, R.; Goodwin, J.G. Jr.; Jothimurugesan, K.

2000-05-01

Attrition resistance is one of the key design parameters for catalysts used in fluidized-bed and slurry phase types of reactors. The ASTM fluidized-bed test has been one of the most commonly used attrition resistance evaluation methods; however, it requires the use of 50 g samples--a large amount for catalyst development studies. Recently a test using the jet cup requiring only 5 g samples has been proposed. In the present study, two series of spray-dried iron catalysts were evaluated using both the ASTM fluidized-bed test and a test based on the jet cup to determine this comparability. It is shown thatmore » the two tests give comparable results. This paper, by reporting a comparison of the jet-cup test with the ASTM standard, provides a basis for utilizing the more efficient jet cup with confidence in catalyst attrition studies.« less

Rapid starting methanol reactor system

DOEpatents

Chludzinski, Paul J.; Dantowitz, Philip; McElroy, James F.

1984-01-01

The invention relates to a methanol-to-hydrogen cracking reactor for use with a fuel cell vehicular power plant. The system is particularly designed for rapid start-up of the catalytic methanol cracking reactor after an extended shut-down period, i.e., after the vehicular fuel cell power plant has been inoperative overnight. Rapid system start-up is accomplished by a combination of direct and indirect heating of the cracking catalyst. Initially, liquid methanol is burned with a stoichiometric or slightly lean air mixture in the combustion chamber of the reactor assembly. The hot combustion gas travels down a flue gas chamber in heat exchange relationship with the catalytic cracking chamber transferring heat across the catalyst chamber wall to heat the catalyst indirectly. The combustion gas is then diverted back through the catalyst bed to heat the catalyst pellets directly. When the cracking reactor temperature reaches operating temperature, methanol combustion is stopped and a hot gas valve is switched to route the flue gas overboard, with methanol being fed directly to the catalytic cracking reactor. Thereafter, the burner operates on excess hydrogen from the fuel cells.

Immobilized glucose oxidase--catalase and their deactivation in a differential-bed loop reactor.

PubMed

Prenosil, J E

1979-01-01

Glucose oxidase containing catalase was immobilized with a copolymer of phenylenediamine and glutaraldehyde on pumice and titania carrier to study the enzymatic oxidation of glucose in a differential-bed loop reactor. The reaction rate was found to be first order with respect to the concentration of limiting oxygen substrate, suggesting a strong external mass-transfer resistance for all the flow rates used. The partial pressure of oxygen was varied from 21.3 up to 202.6 kPa. The use of a differential-bed loop reactor for the determination of the active enzyme concentration in the catalyst with negligible internal pore diffusion resistance is shown. Catalyst deactivation was studied, especially with respect to the presence of catalase. It is believed that the hydrogen peroxide formed in the oxidation reaction deactivates catalase first; if an excess of catalase is present, the deactivation of glucose oxidase remains small. The mathematical model subsequently developed adequately describes the experimental results.

Catalytic recombination of dissociation products with Pt/SnO2 for rare and common isotope long-life, closed-cycle CO2 lasers

NASA Technical Reports Server (NTRS)

Brown, Kenneth G.; Sidney, B. D.; Schryer, D. R.; Upchurch, B. T.; Miller, I. M.

1986-01-01

This paper reports results on recombination of pulsed CO2 laser dissociation products with Pt/SnO2 catalysts, and supporting studies in a surrogate laboratory catalyst reactor. The closed-cycle, pulsed CO2 laser has been continuously operated for one million pulses with an overall power degradation of less than 5 percent by flowing the laser gas mixture through a 2-percent Pt/SnO2 catalyst bed. In the surrogate laboratory reactor, experiments have been conducted to determine isotopic exchange with the catalyst when using rare-isotope gases. The effects of catalyst pretreatment, sample weight, composition, and temperature on catalyst efficiency have also been determined.

Improved hydrocracker temperature control: Mobil quench zone technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarli, M.S.; McGovern, S.J.; Lewis, D.W.

1993-01-01

Hydrocracking is a well established process in the oil refining industry. There are over 2.7 million barrels of installed capacity world-wide. The hydrocracking process comprises several families of highly exothermic reactions and the total adiabatic temperature rise can easily exceed 200 F. Reactor temperature control is therefore very important. Hydrocracking reactors are typically constructed with multiple catalyst beds in series. Cold recycle gas is usually injected between the catalyst beds to quench the reactions, thereby controlling overall temperature rise. The design of this quench zone is the key to good reactor temperature control, particularly when processing poorer quality, i.e., highermore » heat release, feeds. Mobil Research and Development Corporation (MRDC) has developed a robust and very effective quench zone technology (QZT) package, which is now being licensed to the industry for hydrocracking applications.« less

Catalytic pyrolysis of Alcea pallida stems in a fixed-bed reactor for production of liquid bio-fuels.

PubMed

Aysu, Tevfik

2015-09-01

Pyrolysis of Alcea pallida stems was performed in a fixed-bed tubular reactor with and without catalyst at three different temperatures. The effects of pyrolysis parameters including temperature and catalyst on the product yields were investigated. It was found that higher temperature resulted in lower liquid (bio-oil) and solid (bio-char) yields and higher gas yields. Catalysts had different effects on product yields and composition of bio-oils. Liquid yields were increased in the presence of zinc chloride and alumina but decreased with calcium hydroxide, tincal and ulexite. The highest bio-oil yield (39.35%) by weight including aqueous phase was produced with alumina catalyst at 500 °C. The yields of bio-char, bio-oil and gas produced, as well as the compositions of the resulting bio-oils were determined by elemental analysis, TGA, FT-IR and GC-MS. 160 different compounds were identified by GC-MS in the bio-oils obtained at 500 °C. Copyright © 2015 Elsevier Ltd. All rights reserved.

Treatment of ammonia by catalytic wet oxidation process over platinum-rhodium bimetallic catalyst in a trickle-bed reactor: effect of pH.

PubMed

Hung, Chang-Mao; Lin, Wei-Bang; Ho, Ching-Lin; Shen, Yun-Hwei; Hsia, Shao-Yi

2010-08-01

This work adopted aqueous solutions of ammonia for use in catalytic liquid-phase reduction in a trickle-bed reactor with a platinum-rhodium bimetallic catalyst, prepared by the co-precipitation of chloroplatinic acid (H2PtCl6) and rhodium nitrate [Rh(NO3)3]. The experimental results demonstrated that a minimal amount of ammonia was removed from the solution by wet oxidation in the absence of any catalyst, while approximately 97.0% of the ammonia was removed by wet oxidation over the platinum-rhodium bimetallic catalyst at 230 degrees C with an oxygen partial pressure of 2.0 MPa. The oxidation of ammonia has been studied as a function of pH, and the main reaction products were determined. A synergistic effect is manifest in the platinum-rhodium bimetallic structure, in which the material has the greatest capacity to reduce ammonia. The reaction pathway linked the oxidizing ammonia to nitric oxide, nitrogen, and water.

Catalytic wet air oxidation of bisphenol A solution in a batch-recycle trickle-bed reactor over titanate nanotube-based catalysts.

PubMed

Kaplan, Renata; Erjavec, Boštjan; Senila, Marin; Pintar, Albin

2014-10-01

Catalytic wet air oxidation (CWAO) is classified as an advanced oxidation process, which proved to be highly efficient for the removal of emerging organic pollutant bisphenol A (BPA) from water. In this study, BPA was successfully removed in a batch-recycle trickle-bed reactor over bare titanate nanotube-based catalysts at very short space time of 0.6 min gCAT g(-1). The as-prepared titanate nanotubes, which underwent heat treatment at 600 °C, showed high activity for the removal of aqueous BPA. Liquid-phase recycling (5- or 10-fold recycle) enabled complete BPA conversion already at 200 °C, together with high conversion of total organic carbon (TOC), i.e., 73 and 98 %, respectively. The catalyst was chemically stable in the given range of operating conditions for 189 h on stream.

Atmospheric Pressure Non-Thermal Plasma Activation of CO2 in a Packed-Bed Dielectric Barrier Discharge Reactor.

PubMed

Mei, Danhua; Tu, Xin

2017-11-17

Direct conversion of CO 2 into CO and O 2 is performed in a packed-bed dielectric barrier discharge (DBD) non-thermal plasma reactor at low temperatures and atmospheric pressure. The maximum CO 2 conversion of 22.6 % is achieved when BaTiO 3 pellets are fully packed into the discharge gap. The introduction of γ-Al 2 O 3 or 10 wt % Ni/γ-Al 2 O 3 catalyst into the BaTiO 3 packed DBD reactor increases both CO 2 conversion and energy efficiency of the plasma process. Packing γ-Al 2 O 3 or 10 wt % Ni/γ-Al 2 O 3 upstream of the BaTiO 3 bed shows higher CO 2 conversion and energy efficiency compared with that of mid- or downstream packing modes because the reverse reaction of CO 2 conversion-the recombination of CO and O to form CO 2 -is more likely to occur in mid- and downstream modes. Compared with the γ-Al 2 O 3 support, the coupling of the DBD with the Ni catalyst shows a higher CO 2 conversion, which can be attributed to the presence of Ni active species on the catalyst surface. The argon plasma treatment of the reacted Ni catalyst provides extra evidence to confirm the role of Ni active species in the conversion of CO 2 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modeling a Packed Bed Reactor Utilizing the Sabatier Process

NASA Technical Reports Server (NTRS)

Shah, Malay G.; Meier, Anne J.; Hintze, Paul E.

2017-01-01

A numerical model is being developed using Python which characterizes the conversion and temperature profiles of a packed bed reactor (PBR) that utilizes the Sabatier process; the reaction produces methane and water from carbon dioxide and hydrogen. While the specific kinetics of the Sabatier reaction on the RuAl2O3 catalyst pellets are unknown, an empirical reaction rate equation1 is used for the overall reaction. As this reaction is highly exothermic, proper thermal control is of the utmost importance to ensure maximum conversion and to avoid reactor runaway. It is therefore necessary to determine what wall temperature profile will ensure safe and efficient operation of the reactor. This wall temperature will be maintained by active thermal controls on the outer surface of the reactor. Two cylindrical PBRs are currently being tested experimentally and will be used for validation of the Python model. They are similar in design except one of them is larger and incorporates a preheat loop by feeding the reactant gas through a pipe along the center of the catalyst bed. The further complexity of adding a preheat pipe to the model to mimic the larger reactor is yet to be implemented and validated; preliminary validation is done using the smaller PBR with no reactant preheating. When mapping experimental values of the wall temperature from the smaller PBR into the Python model, a good approximation of the total conversion and temperature profile has been achieved. A separate CFD model incorporates more complex three-dimensional effects by including the solid catalyst pellets within the domain. The goal is to improve the Python model to the point where the results of other reactor geometry can be reasonably predicted relatively quickly when compared to the much more computationally expensive CFD approach. Once a reactor size is narrowed down using the Python approach, CFD will be used to generate a more thorough prediction of the reactors performance.

Methyl chloride via oxyhydrochlorination of methane: A building block for chemicals and fuels from natural gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benson, R.L.; Brown, S.S.D.; Ferguson, S.P.

1995-12-31

The objectives of this program are to (a) develop a process for converting natural gas to methyl chloride via an oxyhydrochlorination route using highly selective, stable catalysts in a fixed-bed, (b) design a reactor capable of removing the large amount of heat generated in the process so as to control the reaction, (c) develop a recovery system capable of removing the methyl chloride from the product stream and (d) determine the economics and commercial viability of the process. The general approach has been as follows: (a) design and build a laboratory scale reactor, (b) define and synthesize suitable OHC catalystsmore » for evaluation, (c) select first generation OHC catalyst for Process Development Unit (PDU) trials, (d) design, construct and startup PDU, (e) evaluate packed bed reactor design, (f) optimize process, in particular, product recovery operations, (g) determine economics of process, (h) complete preliminary engineering design for Phase II and (i) make scale-up decision and formulate business plan for Phase II. Conclusions regarding process development and catalyst development are presented.« less

Motor fuels and chemicals from coal via the Sasol Synthol route

NASA Astrophysics Data System (ADS)

Hoogendoorn, J. C.

1981-03-01

The production of synthetic motor fuels and chemicals from coal by the Sasol procedures is discussed. This process is based on the Fischer-Tropsch reaction by passing hydrogen and carbon monoxide in a specific ratio over iron catalysts at elevated temperatures and pressures. Two parallel reactor systems are discussed. The smaller system employs fixed-bed reactors, using a precipitated iron catalyst and produces predominantly heavy hydrocarbons of an aliphatic nature with carbon chains up to 100. These straight-chain hydrocarbons yield excellent waxes and high quality diesel oil. The larger system uses a powdered iron catalyst in a circulating fluid-bed reactor, a concept developed from American catalytic cracker technology. This system has the advantage of high production capacity and scale-up potential, and produces light olefins which can be used either as petrochemical feedstock or refined and added to the motor fuel pool, and ethylene which is augmented by ethane cracking. Analysis of product selectivities and values shows that co-production of chemicals and motor fuels from coal is profitable and efficient.

Synthesis of Biodiesel in Batch and Packed-Bed Reactors Using Powdered and Granular Sugar Catalyst

NASA Astrophysics Data System (ADS)

Janaun, J.; Lim, P. M.; Balan, W. S.; Yaser, A. Z.; Chong, K. P.

2017-06-01

Increasing world production of palm oil warrants effective utilization of its waste. In particular, conversion of waste cooking oil into biodiesel has obtained global interest because of renewable energy need and reduction of CO2 emission. In this study, oleic acid used as a model compound for waste cooking oil conversion using esterification reaction catalysed by sugar catalyst (SC) in powdered (P-SC) and granular (G-SC) forms. The catalysts were synthesized via incomplete carbonization of D-glucose followed by functionalization with concentrated sulphuric acid. Catalysts characterizations were done for their physical and chemical properties using modern tools. Batch and packed-bed reactor systems were used to evaluate the reactivity of the catalysts. The results showed that G-SC had slightly higher total acidity and more porous than P-SC. The experimental conditions for batch reaction were temperature of 60°C, molar ratio of 1:20 (Oleic Acid:Methanol) and 2 wt. catalyst with respect to oleic acid. The results showed the maximum oleic acid conversion using G-SC and P-SC were 52 and 48, respectively. Whereas, the continuous reaction with varying feed flow rate as a function of retention time was studied by using 3 g of P-SC in 60 °C and 1:20 molar ratio in a packed-bed reactor. The results showed that a longer retention time which was 6.48 min and feed flow rate 1.38 ml/min, achieved higher average conversion of 9.9 and decreased with further increasing flow rate. G-SC showed a better average conversion of 10.8 at lowest feed flow rate of 1.38 ml/min in continuous reaction experiments. In a broader perspective, large scale continuous biodiesel production is feasible using granular over powdered catalyst mainly due to it lower pressure drop.

Design of slurry bubble column reactors: novel technique for optimum catalyst size selection contractual origin of the invention

DOEpatents

Gamwo, Isaac K [Murrysville, PA; Gidaspow, Dimitri [Northbrook, IL; Jung, Jonghwun [Naperville, IL

2009-11-17

A method for determining optimum catalyst particle size for a gas-solid, liquid-solid, or gas-liquid-solid fluidized bed reactor such as a slurry bubble column reactor (SBCR) for converting synthesis gas into liquid fuels considers the complete granular temperature balance based on the kinetic theory of granular flow, the effect of a volumetric mass transfer coefficient between the liquid and the gas, and the water gas shift reaction. The granular temperature of the catalyst particles representing the kinetic energy of the catalyst particles is measured and the volumetric mass transfer coefficient between the gas and liquid phases is calculated using the granular temperature. Catalyst particle size is varied from 20 .mu.m to 120 .mu.m and a maximum mass transfer coefficient corresponding to optimum liquid hydrocarbon fuel production is determined. Optimum catalyst particle size for maximum methanol production in a SBCR was determined to be in the range of 60-70 .mu.m.

Carbon nanotubes shynthesis in fluidized bed reactor equipped with a cyclone

NASA Astrophysics Data System (ADS)

Setyopratomo, P.; Sudibandriyo, M.; Wulan, P. P. D. K.

2018-03-01

This work aimed to observe the performance of a fluidized bed reactor which was equipped with a cyclone in the synthesis of carbon nanotubes (CNT) by chemical vapor deposition. Liquefied petroleum gas with a constant volumetric flow rate of 1940 cm3/minutes was fed to the reactor as a carbon source, while a combination of metal components of Fe-Co-Mo supported on MgO was used as catalyst. The CNT synthesis was carried out at a reaction temperature which was maintained at around 800 – 850 °C for 1 hour. The CNT yield was decreased sharply when the catalyst feed was increased. The carbon efficiency is directly proportional to the mass of catalyst fed. It was found from the experiment that the mass of as-grown CNT increased in proportion to the increase of the catalyst mass fed. A sharp increase of the mass percentage of carbon nanotubes entrainment happened when the catalyst feed was raised from 3 to 7 grams. Agglomerates of carbon nanotubes have been formed. The agglomerates composed of mutually entangled carbon nanotubes which have an outer diameter range 8 – 14 nm and an inner diameter range 4 – 10 nm, which confirmed that the multi-walled carbon nanotubes were formed in this synthesis. It was found that the mesopores dominate the pore structure of the CNT product and contribute more than 90 % of the total pore volume.

Fluidised bed catalytic pyrolysis of scrap tyres: influence of catalyst:tyre ratio and catalyst temperature.

PubMed

Williams, Paul T; Brindle, Alexander J

2002-12-01

Pyrolysis with on-line Zeolite catalysis of scrap tyres was undertaken in a fluidised bed reactor with the aim of maximising the production of higher value single ring aromatic hydrocarbons in the derived oil. Experiments were carried out in relation to the ratio of the catalyst to tyre feedstock and the temperature of the catalyst bed. Two Zeolite catalysts were examined, a Y-type Zeolite catalyst and Zeolite ZSM-5 catalyst of differing pore size and surface activity. The composition of the oils derived from the uncatalysed fluidised bed pyrolysis of tyres showed that benzene concentration was 0.2 wt%, toluene concentration was 0.8 wt%, o-xylene was 0.3 wt%, m/p-xylenes were 1.8 wt% and limonene was 4.3 wt%. Benzene, toluene and xylenes present in the oils showed a significant increase in the presence of both of the catalysts. The maximum concentrations of these chemicals for the Y-Zeolite (CBV-400) catalyst was 1 wt% for benzene, 8wt% for toluene, 3 wt% for o-xylene and 8.5 wt% for m/p-xylenes, produced at a catalyst:tyre ratio of 1.5. There was less influence of catalyst temperature on the yield of benzene, toluene and xylenes, however, increasing the temperature of the catalyst resulted in a marked decrease in limonene concentration. The Y-type Zeolite catalyst produced significantly higher concentrations of benzene, toluene and xylenes which was attributed to the larger pore size and higher surface acidity of the Y-Zeolite catalyst compared to the Zeolite ZSM-5 catalyst.

FIXED-BED HYDROGENATION OF ORGANIC COMPOUNDS IN SUPERCRITICAL CARBON DIOXIDE. (R826034)

EPA Science Inventory

Abstract

The Pd/C hydrogenation of cyclohexene to cyclohexane was performed in a continuous fixed-bed reactor employing CO₂ to solubilize the reaction mixture in a single supercritical (sc) phase surrounding the solid catalyst. Employing an equimolar feed of...

Oxidative coupling of methane using inorganic membrane reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Y.H.; Moser, W.R.; Dixon, A.G.

1995-12-31

The goal of this research is to improve the oxidative coupling of methane in a catalytic inorganic membrane reactor. A specific target is to achieve conversion of methane to C{sub 2} hydrocarbons at very high selectivity and relatively higher yields than in fixed bed reactors by controlling the oxygen supply through the membrane. A membrane reactor has the advantage of precisely controlling the rate of delivery of oxygen to the catalyst. This facility permits balancing the rate of oxidation and reduction of the catalyst. In addition, membrane reactors minimize the concentration of gas phase oxygen thus reducing non selective gasmore » phase reactions, which are believed to be a main route for formation of CO{sub x} products. Such gas phase reactions are a cause for decreased selectivity in oxidative coupling of methane in conventional flow reactors. Membrane reactors could also produce higher product yields by providing better distribution of the reactant gases over the catalyst than the conventional plug flow reactors. Modeling work which aimed at predicting the observed experimental trends in porous membrane reactors was also undertaken in this research program.« less

Catalysts at work: From integral to spatially resolved X-ray absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grunwaldt, Jan-Dierk; Kimmerle, Bertram; Baiker, Alfons

2009-09-25

Spectroscopic studies on heterogeneous catalysts have mostly been done in an integral mode. However, in many cases spatial variations in catalyst structure can occur, e.g. during impregnation of pre-shaped particles, during reaction in a catalytic reactor, or in microstructured reactors as the present overview shows. Therefore, spatially resolved molecular information on a microscale is required for a comprehensive understanding of theses systems, partly in ex situ studies, partly under stationary reaction conditions and in some cases even under dynamic reaction conditions. Among the different available techniques, X-ray absorption spectroscopy (XAS) is a well-suited tool for this purpose as the differentmore » selected examples highlight. Two different techniques, scanning and full-field X-ray microscopy/tomography, are described and compared. At first, the tomographic structure of impregnated alumina pellets is presented using full-field transmission microtomography and compared to the results obtained with a scanning X-ray microbeam technique to analyse the catalyst bed inside a catalytic quartz glass reactor. On the other hand, by using XAS in scanning microtomography, the structure and the distribution of Cu(0), Cu(I), Cu(II) species in a Cu/ZnO catalyst loaded in a quartz capillary microreactor could be reconstructed quantitatively on a virtual section through the reactor. An illustrating example for spatially resolved XAS under reaction conditions is the partial oxidation of methane over noble metal-based catalysts. In order to obtain spectroscopic information on the spatial variation of the oxidation state of the catalyst inside the reactor XAS spectra were recorded by scanning with a micro-focussed beam along the catalyst bed. Alternatively, full-field transmission imaging was used to efficiently determine the distribution of the oxidation state of a catalyst inside a reactor under reaction conditions. The new technical approaches together with quantitative data analysis and an appropriate in situ catalytic experiment allowed drawing important conclusions on the reaction mechanism, and the analytical strategy might be similarly applied in other case studies. The corresponding temperature profiles and the catalytic performance were measured by means of an IR-camera and mass spectrometric analysis. In a more advanced experiment the ignition process of the partial oxidation of methane was followed in a spatiotemporal manner which demonstrates that spatially resolved spectroscopic information can even be obtained in the subsecond scale.« less

Steam reforming of heptane in a fluidized bed membrane reactor

NASA Astrophysics Data System (ADS)

Rakib, Mohammad A.; Grace, John R.; Lim, C. Jim; Elnashaie, Said S. E. H.

n-Heptane served as a model compound to study steam reforming of naphtha as an alternative feedstock to natural gas for production of pure hydrogen in a fluidized bed membrane reactor. Selective removal of hydrogen using Pd 77Ag 23 membrane panels shifted the equilibrium-limited reactions to greater conversion of the hydrocarbons and lower yields of methane, an intermediate product. Experiments were conducted with no membranes, with one membrane panel, and with six panels along the height of the reactor to understand the performance improvement due to hydrogen removal in a reactor where catalyst particles were fluidized. Results indicate that a fluidized bed membrane reactor (FBMR) can provide a compact reformer for pure hydrogen production from a liquid hydrocarbon feedstock at moderate temperatures (475-550 °C). Under the experimental conditions investigated, the maximum achieved yield of pure hydrogen was 14.7 moles of pure hydrogen per mole of heptane fed.

Iron catalyzed coal liquefaction process

DOEpatents

Garg, Diwakar; Givens, Edwin N.

1983-01-01

A process is described for the solvent refining of coal into a gas product, a liquid product and a normally solid dissolved product. Particulate coal and a unique co-catalyst system are suspended in a coal solvent and processed in a coal liquefaction reactor, preferably an ebullated bed reactor. The co-catalyst system comprises a combination of a stoichiometric excess of iron oxide and pyrite which reduce predominantly to active iron sulfide catalysts in the reaction zone. This catalyst system results in increased catalytic activity with attendant improved coal conversion and enhanced oil product distribution as well as reduced sulfide effluent. Iron oxide is used in a stoichiometric excess of that required to react with sulfur indigenous to the feed coal and that produced during reduction of the pyrite catalyst to iron sulfide.

Comparison of non-catalytic and catalytic fast pyrolysis of corncob in a fluidized bed reactor.

PubMed

Zhang, Huiyan; Xiao, Rui; Huang, He; Xiao, Gang

2009-02-01

Fast pyrolysis of corncob with and without catalyst was investigated in a fluidized bed to determine the effects of pyrolysis parameters (temperature, gas flow rate, static bed height and particle size) and a HZSM-5 zeolite catalyst on the product yields and the qualities of the liquid products. The result showed that the optimal conditions for liquid yield (56.8%) were a pyrolysis temperature of 550 degrees C, gas flow rate of 3.4 L/min, static bed height of 10 cm and particle size of 1.0-2.0mm. The presence of the catalyst increased the yields of non-condensable gas, water and coke, while decreased the liquid and char yields. The elemental analysis showed that more than 25% decrease in oxygen content of the collected liquid in the second condenser with HZSM-5 was observed compared with that without catalyst. The H/C, O/C molar ratios and the higher heating value of the oil fraction in the collected liquid with the catalyst were 1.511, 0.149 and 34.6 MJ/kg, respectively. It was indicated that the collected liquid in the second condenser had high qualities and might be used as transport oil.

Direct Synthesis of Renewable Dodecanol and Dodecane with Methyl Isobutyl Ketone over Dual-Bed Catalyst Systems.

PubMed

Sheng, Xueru; Li, Ning; Li, Guangyi; Wang, Wentao; Wang, Aiqin; Cong, Yu; Wang, Xiaodong; Zhang, Tao

2017-03-09

For the first time, we demonstrated two integrated processes for the direct synthesis of dodecanol or 2,4,8-trimethylnonane (a jet fuel range C 12 -branched alkane) using methyl isobutyl ketone (MIBK) that can be derived from lignocellulose. The reactions were carried out in dual-bed continuous flow reactors. In the first bed, MIBK was selectively converted to a mixture of C 12 alcohol and ketone. Over the Pd-modified magnesium- aluminium hydrotalcite (Pd-MgAl-HT) catalyst, a high total carbon yield (73.0 %) of C 12 oxygenates can be achieved under mild conditions. In the second bed, the C 12 oxygenates generated in the first bed were hydrogenated to dodecanol over a Ru/C catalyst or hydrodeoxygenated to 2,4,8-trimethylnonane over a Cu/SiO 2 catalyst. The as-obtained dodecanol can be used as feedstock in the production of sodium dodecylsulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS), which are widely used as surfactants or detergents. The asobtained 2,4,8-trimethylnonane can be blended into conventional jet fuel without hydroisomerization. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solar heated fluidized bed gasification system

NASA Technical Reports Server (NTRS)

Qader, S. A. (Inventor)

1981-01-01

A solar-powered fluidized bed gasification system for gasifying carbonaceous material is presented. The system includes a solar gasifier which is heated by fluidizing gas and steam. Energy to heat the gas and steam is supplied by a high heat capacity refractory honeycomb which surrounds the fluid bed reactor zone. The high heat capacity refractory honeycomb is heated by solar energy focused on the honeycomb by solar concentrator through solar window. The fluid bed reaction zone is also heated directly and uniformly by thermal contact of the high heat capacity ceramic honeycomb with the walls of the fluidized bed reactor. Provisions are also made for recovering and recycling catalysts used in the gasification process. Back-up furnace is provided for start-up procedures and for supplying heat to the fluid bed reaction zone when adequate supplies of solar energy are not available.

Rotating packed bed reactor for enzymatic synthesis of biodiesel.

PubMed

Xu, Juntao; Liu, Changsheng; Wang, Meng; Shao, Lei; Deng, Li; Nie, Kaili; Wang, Fang

2017-01-01

The aim of the present work was to study the applicability of rotating packed bed (RPB) for biodiesel through the biocatalytic method. In this research, the RPB facilitated a more homogeneous mixture of substrates due to its higher mass transfer efficiency and better micromixing environment. This was superior to the traditional continuous stirred tank reactor (CSTR) system. Candida sp. 99-125 lipase was used without any organic solvent or additive, and demonstrated a significant catalyst efficiency. The key factors, such as the high gravity factor (β), pattern of the catalyst and methanol-FFA molar ratio etc. were investigated. Under the optimal conditions, the hydrolysis yield of fatty acids was 97.0% after 24h and the esterification yield of biodiesel was 96.0% 6h later. The esterifying yield didn't have an obvious decline in the fifth batch. Consequently, the RPB is an attractive and effective reactor for enzymatic synthesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of Advanced ISS-WPA Catalysts for Organic Oxidation at Reduced Pressure/Temperature

NASA Technical Reports Server (NTRS)

Yu, Ping; Nalette, Tim; Kayatin, Matthew

2016-01-01

The Water Processor Assembly (WPA) at International Space Station (ISS) processes a waste stream via multi-filtration beds, where inorganic and non-volatile organic contaminants are removed, and a catalytic reactor, where low molecular weight organics not removed by the adsorption process are oxidized at elevated pressure in the presence of oxygen and elevated temperature above the normal water boiling point. Operation at an elevated pressure requires a more complex system design compared to a reactor that could operate at ambient pressure. However, catalysts currently available have insufficient activity to achieve complete oxidation of the organic load at a temperature less than the water boiling point and ambient pressure. Therefore, it is highly desirable to develop a more active and efficient catalyst at ambient pressure and a moderate temperature that is less than water boiling temperature. This paper describes our efforts in developing high efficiency water processing catalysts. Different catalyst support structures and coating metals were investigated in subscale reactors and results were compared against the flight WPA catalyst. Detailed improvements achieved on alternate metal catalysts at ambient pressure and 200 F will also be presented in the paper.

Mars Atmospheric Conversion to Methane and Water: An Engineering Model of the Sabatier Reactor with Characterization of Ru/Al2O3 for Long Duration Use on Mars

NASA Technical Reports Server (NTRS)

Meier, Anne J.; Shah, Malay; Petersen, Elspeth; Hintze, Paul; Muscatello, Tony

2017-01-01

The Atmospheric Processing Module (APM) is a Mars In-Situ Resource Utilization (ISRU) technology designed to demonstrate conversion of the Martian atmosphere into methane and water. The Martian atmosphere consists of approximately 95 carbon dioxide (CO2) and residual argon and nitrogen. APM utilizes cryocoolers for CO2 acquisition from a simulated Martian atmosphere and pressure. The captured CO2 is sublimated and pressurized as a feedstock into the Sabatier reactor, which converts CO2 and hydrogen to methane and water. The Sabatier reaction occurs over a packed bed reactor filled with Ru/Al2O3 pellets. The long duration use of the APM system and catalyst was investigated for future scaling and failure limits. Failure of the catalyst was detected by gas chromatography and temperature sensors on the system. Following this, characterization and experimentation with the catalyst was carried out with analysis including x-ray photoelectron spectroscopy and scanning electron microscopy with elemental dispersive spectroscopy. This paper will discuss results of the catalyst performance, the overall APM Sabatier approach, as well as intrinsic catalyst considerations of the Sabatier reactor performance incorporated into a chemical model.

Effect of Electric Discharge on Properties of Nano-Particulate Catalyst for Plasma-Catalysis.

PubMed

Lee, Chung Jun; Kim, Jip; Kim, Taegyu

2016-02-01

Heterogeneous catalytic processes have been used to produce hydrogen from hydrocarbons. However, high reforming temperature caused serious catalyst deteriorations and low energy efficiency. Recently, a plasma-catalyst hybrid process was used to reduce the reforming temperature and to improve the stability and durability of reforming catalysts. Effect of electric discharges on properties of nanoparticulate catalysts for plasma-catalysis was investigated in the present study. Catalyst-bed porosity was varied by packing catalyst beads with the different size in a reactor. Discharge power and onset voltage of the plasma were measured as the catalyst-bed porosity was varied. The effect of discharge voltage, frequency and voltage waveforms such as the sine, pulse and square was investigated. We found that the optimal porosity of the catalyst-bed exists to maximize the electric discharge. At a low porosity, the electric discharge was unstable to be sustained because the space between catalysts got narrow nearly close to the sheath region. On the other hand, at a high porosity, the electric discharge became weak because the plasma was not sufficient to interact with the surface of catalysts. The discharge power increased as the discharge voltage and frequency increased. The square waveform was more efficient than the sine and pulse one. At a high porosity, however, the effect of the voltage waveform was not considerable because the space between catalysts was too large for plasma to interact with the surface of catalysts.

Applicability of fluidized bed reactor in recalcitrant compound degradation through advanced oxidation processes: a review.

PubMed

Tisa, Farhana; Abdul Raman, Abdul Aziz; Wan Daud, Wan Mohd Ashri

2014-12-15

Treatment of industrial waste water (e.g. textile waste water, phenol waste water, pharmaceutical etc) faces limitation in conventional treatment procedures. Advanced oxidation processes (AOPs) do not suffer from the limits of conventional treatment processes and consequently degrade toxic pollutants more efficiently. Complexity is faced in eradicating the restrictions of AOPs such as sludge formation, toxic intermediates formation and high requirement for oxidants. Increased mass-transfer in AOPs is an alternate solution to this problem. AOPs combined with Fluidized bed reactor (FBR) can be a potential choice compared to fixed bed or moving bed reactor, as AOP catalysts life-span last for only maximum of 5-10 cycles. Hence, FBR-AOPs require lesser operational and maintenance cost by reducing material resources. The time required for AOP can be minimized using FBR and also treatable working volume can be increased. FBR-AOP can process from 1 to 10 L of volume which is 10 times more than simple batch reaction. The mass transfer is higher thus the reaction time is lesser. For having increased mass transfer sludge production can be successfully avoided. The review study suggests that, optimum particle size, catalyst to reactor volume ratio, catalyst diameter and liquid or gas velocity is required for efficient FBR-AOP systems. However, FBR-AOPs are still under lab-scale investigation and for industrial application cost study is needed. Cost of FBR-AOPs highly depends on energy density needed and the mechanism of degradation of the pollutant. The cost of waste water treatment containing azo dyes was found to be US$ 50 to US$ 500 per 1000 gallons where, the cost for treating phenol water was US$ 50 to US$ 800 per 1000 gallons. The analysis for FBR-AOP costs has been found to depend on the targeted pollutant, degradation mechanism (zero order, 1st order and 2nd order) and energy consumptions by the AOPs. Copyright © 2014 Elsevier Ltd. All rights reserved.

AN INVESTIGATION OF CFC12 (CCI2F2) DECOMPOSITION ON TIO2 CATALYST

EPA Science Inventory

The catalytic oxidation of CFC12 was studied over a titania (TiO2) catalyst in a fixed-bed reactor at temperatures ranging from 200 to 400 degrees C and space velocity of 10,500 h-1. Results showed substantially complete conversion of CFC12 (>90%) to CO2 and halogen acids at and...

Carbon Dioxide Methanation for Human Exploration of Mars: A Look at Catalyst Longevity and Activity Using Supported Ruthenium

NASA Technical Reports Server (NTRS)

Petersen, Elspeth M.; Meier, Anne J.; Tessonnier, Jean-Philippe

2018-01-01

Overarching Purpose: To design a carbon dioxide methanation/Sabatier reaction catalyst able to withstand variable conditions including fluctuations in bed temperature and feed flow rates for 480 days of remote operation to produce seven tons of methane. Current Study Purpose: Examine supported Ruthenium as a carbon dioxide methanation catalyst to determine the effects support properties have on the active phase by studying activity and selectivity. Objective: The remote operation of the Mars ISRU (In Situ Resources Utilization) lander to produce rocket fuel prior to crew arrival on the planet to power an ascent vehicle. Constraints: Long-term operation (480 days); Variable conditions: Feed gas flow rates, Feed gas flow ratios, Reactor bed temperature.

A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed-bed microreactor

PubMed Central

Bogdan, Andrew

2009-01-01

Summary We demonstrate the preparation and characterization of a simplified packed-bed microreactor using an immobilized TEMPO catalyst shown to oxidize primary and secondary alcohols via the biphasic Anelli-Montanari protocol. Oxidations occurred in high yields with great stability over time. We observed that plugs of aqueous oxidant and organic alcohol entered the reactor as plugs but merged into an emulsion on the packed-bed. The emulsion coalesced into larger plugs upon exiting the reactor, leaving the organic product separate from the aqueous by-products. Furthermore, the microreactor oxidized a wide range of alcohols and remained active in excess of 100 trials without showing any loss of catalytic activity. PMID:19478910

Alternative Fuel Research in Fischer-Tropsch Synthesis

NASA Technical Reports Server (NTRS)

Surgenor, Angela D.; Klettlinger, Jennifer L.; Yen, Chia H.; Nakley, Leah M.

2011-01-01

NASA Glenn Research Center has recently constructed an Alternative Fuels Laboratory which is solely being used to perform Fischer-Tropsch (F-T) reactor studies, novel catalyst development and thermal stability experiments. Facility systems have demonstrated reliability and consistency for continuous and safe operations in Fischer-Tropsch synthesis. The purpose of this test facility is to conduct bench scale Fischer-Tropsch (F-T) catalyst screening experiments while focusing on reducing energy inputs, reducing CO2 emissions and increasing product yields within the F-T process. Fischer-Tropsch synthesis is considered a gas to liquid process which reacts syn-gas (a gaseous mixture of hydrogen and carbon monoxide), over the surface of a catalyst material which is then converted into liquids of various hydrocarbon chain length and product distributions1. These hydrocarbons can then be further processed into higher quality liquid fuels such as gasoline and diesel. The experiments performed in this laboratory will enable the investigation of F-T reaction kinetics to focus on newly formulated catalysts, improved process conditions and enhanced catalyst activation methods. Currently the facility has the capability of performing three simultaneous reactor screening tests, along with a fourth fixed-bed reactor used solely for cobalt catalyst activation.

Study on the decomposition of trace benzene over V2O5–WO3/TiO2-based catalysts in simulated flue gas

EPA Science Inventory

Trace levels (1 and 10 ppm) of gaseous benzene were catalytically decomposed in a fixed-bed catalytic reactor with monolithic oxides of vanadium and tungsten supported on titanium oxide (V2O5–WO3/TiO2) catalysts under conditions simulating the cooling of waste incineration flue g...

Cyclic process for producing methane in a tubular reactor with effective heat removal

DOEpatents

Frost, Albert C.; Yang, Chang-Lee

1986-01-01

Carbon monoxide-containing gas streams are converted to methane by a cyclic, essentially two-step process in which said carbon monoxide is disproportionated to form carbon dioxide and active surface carbon deposited on the surface of a catalyst, and said carbon is reacted with steam to form product methane and by-product carbon dioxide. The exothermic heat of reaction generated in each step is effectively removed during each complete cycle so as to avoid a build up of heat from cycle-to-cycle, with particularly advantageous techniques being employed for fixed bed, tubular and fluidized bed reactor operations.

Impact of different catalysis supported by oyster shells on the pyrolysis of tyre wastes in a single and a double fixed bed reactor.

PubMed

Kordoghli, Sana; Khiari, Besma; Paraschiv, Maria; Zagrouba, Fethi; Tazerout, Mohand

2017-09-01

The treatment and disposal of tyres from vehicles has long been of considerable environmental importance. Studies have been undertaken to reduce their environmental impact. In this study, an alternative gas was produced from automobile tyre wastes by the means of a controlled pyrolysis. To do so, a novel catalytic system was designed with the aim of increasing the rate of conversion and improving the quality of the pyrolysis products. This work aimed also to reduce the severity of the overall reactions, by using powder catalysts (MgO, Al 2 O 3 , CaCO 3 , and zeolite ZSM-5) uniformly distributed on two layers of oyster shells (OS) particles. The catalyst/tyres mass ratio was kept for all the tests at 1/30. The pyrolysis reactor was maintained at 500°C and the influence of each catalyst and of the number of shell beds (0, 1 or 2), on the yield and composition of the derived products, was examined. The gas yields could contribute by 1.2% of total consumption in Tunisia. Furthermore, some combinations could upgrade the derived gas and made it possible to use it as such or with the minimum of post-treatment. It was found that, with the use of supported catalyst, the gas produced is 45% greater compared to classical thermal pyrolysis. The Heating value of the produced gas was also improved by the use of supported catalysts; it was found 16% greater with the use of Al 2 O 3 /OS compared to non-catalytic pyrolysis. When compared to the gas obtained from only one catalytic supported bed, the sulfur content was reduced by 80% with the use of CaCO 3 /OS on two catalytic beds. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development of attrition resistant iron-based Fischer-Tropsch catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2000-09-20

The Fischer-Tropsch (F-T) reaction provides a way of converting coal-derived synthesis gas (CO+H{sub 2}) to liquid fuels. Since the reaction is highly exothermic, one of the major problems in control of the reaction is heat removal. Recent work has shown that the use of slurry bubble column reactors (SBCRs) can largely solve this problem. The use of iron-based catalysts is attractive not only due to their low cost and ready availability, but also due to their high water-gas shift activity which makes it possible to use these catalysts with low H{sub 2}/CO ratios. However, a serious problem with use ofmore » Fe catalysts in a SBCR is their tendency to undergo attrition. This can cause fouling/plugging of downstream filters and equipment, makes the separation of catalyst from the oil/wax product very difficult if not impossible, and results a steady loss of catalyst from the reactor. The objective of this research is to develop robust iron-based Fischer-Tropsch catalysts that have suitable activity, selectivity and stability to be used in the slurry bubble column reactor. Specifically we aim to develop to: (1) improve the performance and preparation procedure of the high activity, high attrition resistant, high alpha iron-based catalysts synthesized at Hampton University (2) seek improvements in the catalyst performance through variations in process conditions, pretreatment procedures and/or modifications in catalyst preparation steps and (3) investigate the performance in a slurry reactor. The effort during the reporting period has been devoted to effects of pretreating procedures, using H{sub 2}, CO and syngas (H{sub 2}/CO = 0.67) as reductants, on the performance (activity, selectivity and stability with time) of a precipitated iron catalyst (100Fe/5Cu/4.2K/10SiO{sub 2} on a mass basis ) during F-T synthesis were studied in a fixed-bed reactor.« less

Structured catalyst bed and method for conversion of feed materials to chemical products and liquid fuels

DOEpatents

Wang, Yong , Liu; Wei, [Richland, WA

2012-01-24

The present invention is a structured monolith reactor and method that provides for controlled Fischer-Tropsch (FT) synthesis. The invention controls mass transport limitations leading to higher CO conversion and lower methane selectivity. Over 95 wt % of the total product liquid hydrocarbons obtained from the monolithic catalyst are in the carbon range of C.sub.5-C.sub.18. The reactor controls readsorption of olefins leading to desired products with a preselected chain length distribution and enhanced overall reaction rate. And, liquid product analysis shows readsorption of olefins is reduced, achieving a narrower FT product distribution.

Selective phenol methylation to 2,6-dimethylphenol in a fluidized bed of iron-chromium mixed oxide catalyst with o-cresol circulation.

PubMed

Zukowski, Witold; Berkowicz, Gabriela; Baron, Jerzy; Kandefer, Stanisław; Jamanek, Dariusz; Szarlik, Stefan; Wielgosz, Zbigniew; Zielecka, Maria

2014-01-01

2,6-dimethylphenol (2,6-DMP) is a product of phenol methylation, especially important for the plastics industry. The process of phenol methylation in the gas phase is strongly exothermic. In order to ensure good temperature equalization in the catalyst bed, the process was carried out using a catalyst in the form of a fluidized bed - in particular, the commercial iron-chromium catalyst TZC-3/1. Synthesis of 2,6-dimethylphenol from phenol and methanol in fluidized bed of iron-chromium catalyst was carried out and the fluidization of the catalyst was examined. Stable state of fluidized bed of iron-chromium catalyst was achieved. The measured velocities allowed to determine the minimum flow of reactants, ensuring introduction of the catalyst bed in the reactor into the state of fluidization. Due to a high content of o-cresol in products of 2,6-dimethylphenol synthesis, circulation in the technological node was proposed. A series of syntheses with variable amount of o-cresol in the feedstock allowed to determine the parameters of stationary states. A stable work of technological node with o-cresol circulation is possible in the temperature range of350-380°C, and o-cresolin/phenolin molar ratio of more than 0.48. Synthesis of 2,6-DMP over the iron-chromium catalyst is characterized by more than 90% degree of phenol conversion. Moreover, the O-alkylation did not occur (which was confirmed by GC-MS analysis). By applying o-cresol circulation in the 2,6-DMP process, selectivity of more than 85% degree of 2,6-DMP was achieved. The participation levels of by-products: 2,4-DMP and 2,4,6-TMP were low. In the optimal conditions based on the highest yield of 2,6-DMP achieved in the technological node applying o-cresol circulation, there are 2%mol. of 2,4-DMP and 6%mol. of 2,4,6-TMP in the final mixture, whereas 2,4,6-TMP can be useful as a chain stopper and polymer's molar mass regulator during the polymerization of 2,6-DMP.

Conversion of Small Algal Oil Sample to JP-8

DTIC Science & Technology

2012-01-01

cracking of Algal Oil to SPK Hydroprocessing Lab Plant uop Nitrogen Hydrogen Product ., __ Small Scale Lab Hydprocessing plant - Down flow trickle ... bed configuration - Capable of retaining 25 cc of catalyst bed Meter UOP ·CONFIDENTIAL File Number The catalytic deoxygenation stage of the...content which combined with the samples acidity, is a challenge to reactor metallurgy. None the less, an attempt was made to convert this sample to

Polymer nanocomposite membranes with hierarchically structured catalysts for high throughput dehalogenation

NASA Astrophysics Data System (ADS)

Crock, Christopher A.

Halogenated organics are categorized as primary pollutants by the Environmental Protection Agency. Trichloroethylene (TCE), which had broad industrial use in the past, shows persistence in the environment because of its chemical stability. The large scale use and poor control of TCE resulted in its prolonged release into the environment before the carcinogenic risk associated with TCE was fully understood. TCE pollution stemmed from industrial effluents and improper disposal of solvent waste. Membrane reactors are promising technology for treating TCE polluted groundwater because of the high throughput, relatively low cost of membrane fabrication and facile retrofitting of existing membrane based water treatment facilities with catalytic membrane reactors. Compared to catalytic fluidized or fixed bed reactors, catalytic membrane reactors feature minimal diffusional limitation. Additionally, embedding catalyst within the membrane avoids the need for catalyst recovery and can prevent aggregation of catalytic nanoparticles. In this work, Pd/xGnP, Pd-Au/xGnP, and commercial Pd/Al2O3 nanoparticles were employed in batch and flow-through membrane reactors to catalyze the dehalogenation of TCE in the presence of dissolved H2. Bimetallic Pd-Au/xGnP catalysts were shown to be more active than monometallic Pd/xGnP or commercial Pd/Al 2O3 catalysts. In addition to synthesizing nanocomposite membranes for high-throughput TCE dehalogenation, the membrane based dehalogenation process was designed to minimize the detrimental impact of common catalyst poisons (S2-, HS-, and H2S -) by concurrent oxidation of sulfide species to gypsum in the presence of Ca2+ and removal of gypsum through membrane filtration. The engineered membrane dehalogenation process demonstrated that bimetallic Pd-Au/xGnP catalysts resisted deactivation by residual sulfide species after oxidation, and showed complete removal of gypsum during membrane filtration.

[Synergetic effects of silicon carbide and molecular sieve loaded catalyst on microwave assisted catalytic oxidation of toluene].

PubMed

Wang, Xiao-Hui; Bo, Long-Li; Liu, Hai-Nan; Zhang, Hao; Sun, Jian-Yu; Yang, Li; Cai, Li-Dong

2013-06-01

Molecular sieve loaded catalyst was prepared by impregnation method, microwave-absorbing material silicon carbide and the catalyst were investigated for catalytic oxidation of toluene by microwave irradiation. Research work examined effects of silicon carbide and molecular sieve loading Cu-V catalyst's mixture ratio as well as mixed approach changes on degradation of toluene, and characteristics of catalyst were measured through scanning electron microscope, specific surface area test and X-ray diffraction analysis. The result showed that the fixed bed reactor had advantages of both thermal storage property and low-temperature catalytic oxidation when 20% silicon carbide was filled at the bottom of the reactor, and this could effectively improve the utilization of microwave energy as well as catalytic oxidation efficiency of toluene. Under microwave power of 75 W and 47 W, complete-combustion temperatures of molecular sieve loaded Cu-V catalyst and Cu-V-Ce catalyst to toluene were 325 degrees C and 160 degrees C, respectively. Characteristics of the catalysts showed that mixture of rare-earth element Ce increased the dispersion of active components in the surface of catalyst, micropore structure of catalyst effectively guaranteed high adsorption capacity for toluene, while amorphous phase of Cu and V oxides increased the activity of catalyst greatly.

Attrition Resistant Iron-Based Catalysts For F-T SBCRs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adeyinka A. Adeyiga

2006-01-31

The Fischer-Tropsch (F-T) reaction provides a way of converting coal-derived synthesis gas (CO+ H{sub 2}) to liquid fuels. Since the reaction is highly exothermic, one of the major problems in control of the reaction is heat removal. Recent work has shown that the use of slurry bubble column reactors (SBCRs) can largely solve this problem. The use of iron-(FE) based catalysts is attractive not only due to their low cost and ready availability, but also due to their high water-gas shift activity which makes it possible to use these catalysts with low H{sub 2}/CO ratios. However, a serious problem withmore » the use of Fe catalysts in a SBCR is their tendency to undergo attrition. This can cause fouling/plugging of downstream filters and equipment; makes the separation of catalyst from the oil/wax product very difficult, if not impossible; and results in a steady loss of catalyst from the reactor. Under a previous Department of Energy (DOE)/University Research Grant (UCR) grant, Hampton University reported, for the first time, the development of demonstrably attrition-resistant Fe F-T synthesis catalysts having good activity, selectivity, and attrition resistance. These catalysts were prepared by spray drying Fe catalysts with potassium (K), copper (Cu), and silica (SiO{sub 2}) as promoters. SiO{sub 2} was also used as a binder for spray drying. These catalysts were tested for activity and selectivity in a laboratory-scale fixed-bed reactor. Fundamental understanding of attrition is being addressed by incorporating suitable binders into the catalyst recipe. This has resulted in the preparation of a spray dried HPR-43 catalyst having average particle size (aps) of 70 {micro}m with high attrition resistance. This HPR-43 attrition resistant, active and selective catalyst gave 95% CO conversion through 125 hours of testing in a fixed-bed at 270 C, 1.48 MPa, H{sub 2}/CO=0.67 and 2.0 NL/g-cat/h with C{sub 5+} selectivity of >78% and methane selectivity of less than 5% at an {alpha} of 0.9. Research is proposed to enable further development and optimization of these catalysts by (1) better understanding the role and interrelationship of various catalyst composition and preparation parameters on attrition resistance, activity, and selectivity of these catalysts, (2) the presence of sulfide ions on a precipitated iron catalyst, and (3) the effect of water on sulfided iron F-T catalysts for its activity, selectivity, and attrition. Catalyst preparations will be based on spray drying. The research employed, among other measurements, attrition testing and F-T synthesis at high pressure. Catalyst activity and selectivity is evaluated using a small fixed-bed reactor and a continuous stirred tank reactor (CSTR). The catalysts were prepared by co-precipitation, followed by binder addition and spray drying at 250 C in a 1-m-diameter, 2-m-tall spray dryer. The binder silica content was varied from 0 to 20 wt%. The results show that the use of small amounts of precipitated SiO{sub 2} alone in spray-dried Fe catalysts can result in good attrition resistance. All catalysts investigated with SiO2 wt% {le} 12 produced fines less than 10 wt% during the jet cup attrition test, making them suitable for long-term use in a slurry bubble column reactor. Thus, concentration rather than the type of SiO{sub 2} incorporated into catalyst has a more critical impact on catalyst attrition resistance of spray-dried Fe catalysts. Lower amounts of SiO{sub 2} added to a catalyst give higher particle densities and therefore higher attrition resistances. In order to produce a suitable SBCR catalyst, however, the amount of SiO{sub 2} added has to be optimized to provide adequate surface area, particle density, and attrition resistance. Two of the catalysts with precipitated and binder silica were tested in Texas A&M University's CSTR (Autoclave Engineers). The two catalysts were also tested at The Center for Applied Energy Research in Lexington, Kentucky of the University of Kentucky. Spray-dried catalysts with compositions 100 Fe/5 Cu/4.2 K/11 (P) SiO{sub 2} and 100 Fe/5 Cu/4.2 K/1.1 (B) SiO{sub 2} have excellent selectivity characteristics (low methane and high C{sub 5+} yields), but their productivity and stability (deactivation rate) need to be improved. Mechanical integrity (attrition strength) of these two catalysts was markedly dependent upon their morphological features. The attrition strength of the catalyst made out of largely spherical particles (1.1 (B) SiO{sub 2}) was considerably higher than that of the catalyst consisting of irregularly shaped particles (11 (P) SiO{sub 2}).« less

Membrane reactor for water detritiation: a parametric study on operating parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mascarade, J.; Liger, K.; Troulay, M.

2015-03-15

This paper presents the results of a parametric study done on a single stage finger-type packed-bed membrane reactor (PBMR) used for heavy water vapor de-deuteration. Parametric studies have been done on 3 operating parameters which are: the membrane temperature, the total feed flow rate and the feed composition through D{sub 2}O content variations. Thanks to mass spectrometer analysis of streams leaving the PBMR, speciation of deuterated species was achieved. Measurement of the amounts of each molecular component allowed the calculation of reaction quotient at the packed-bed outlet. While temperature variation mainly influences permeation efficiency, feed flow rate perturbation reveals dependencemore » of conversion and permeation properties to contact time between catalyst and reacting mixture. The study shows that isotopic exchange reactions occurring on the catalyst particles surface are not thermodynamically balanced. Moreover, the variation of the heavy water content in the feed exhibits competition between permeation and conversion kinetics.« less

Hydrocarbon Liquid Production from Biomass via Hot-Vapor-Filtered Fast Pyrolysis and Catalytic Hydroprocessing of the Bio-oil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, Douglas C.; Wang, Huamin; French, Richard

2014-08-14

Hot-vapor filtered bio-oils were produced from two different biomass feedstocks, oak and switchgrass, and the oils were evaluated in hydroprocessing tests for production of liquid hydrocarbon products. Hot-vapor filtering reduced bio-oil yields and increased gas yields. The yields of fuel carbon as bio-oil were reduced by ten percentage points by hot-vapor filtering for both feedstocks. The unfiltered bio-oils were evaluated alongside the filtered bio-oils using a fixed bed catalytic hydrotreating test. These tests showed good processing results using a two-stage catalytic hydroprocessing strategy. Equal-sized catalyst beds, a sulfided Ru on carbon catalyst bed operated at 220°C and a sulfided CoMomore » on alumina catalyst bed operated at 400°C were used with the entire reactor at 100 atm operating pressure. The products from the four tests were similar. The light oil phase product was fully hydrotreated so that nitrogen and sulfur were below the level of detection, while the residual oxygen ranged from 0.3 to 2.0%. The density of the products varied from 0.80 g/ml up to 0.86 g/ml over the period of the test with a correlated change of the hydrogen to carbon atomic ratio from 1.79 down to 1.57, suggesting some loss of catalyst activity through the test. These tests provided the data needed to assess the suite of liquid fuel products from the process and the activity of the catalyst in relationship to the existing catalyst lifetime barrier for the technology.« less

[Kinetics of catalytic wet air oxidation of phenol in trickle bed reactor].

PubMed

Li, Guang-ming; Zhao, Jian-fu; Wang, Hua; Zhao, Xiu-hua; Zhou, Yang-yuan

2004-05-01

By using a trickle bed reactor which was designed by the authors, the catalytic wet air oxidation reaction of phenol on CuO/gamma-Al2O3 catalyst was studied. The results showed that in mild operation conditions (at temperature of 180 degrees C, pressure of 3 MPa, liquid feed rate of 1.668 L x h(-1) and oxygen feed rate of 160 L x h(-1)), the removal of phenol can be over 90%. The curve of phenol conversion is similar to "S" like autocatalytic reaction, and is accordance with chain reaction of free radical. The kinetic model of pseudo homogenous reactor fits the catalytic wet air oxidation reaction of phenol. The effects of initial concentration of phenol, liquid feed rate and temperature for reaction also were investigated.

Progress in the Production of JP-8 Based Hydrogen and Advanced Tactical Fuels for Military Applications

DTIC Science & Technology

2011-02-01

of a multi- year program to develop, optimize, and demonstrate the military viability of a technology for on-demand production of high...continuous reactor system used for kinetic rate data experiment 86 52 Schematic of a differential reactor. The catalyst bed is kept small , and...program to develop, optimize, and demonstrate the military viability of a technology for on-demand production of high-pressure hydrogen for fuel

Visible-Light-Responsive Photocatalysis: Ag-Doped TiO2 Catalyst Development and Reactor Design Testing

NASA Technical Reports Server (NTRS)

Coutts, Janelle L.; Hintze, Paul E.; Meier, Anne; Shah, Malay G.; Devor, Robert W.; Surma, Jan M.; Maloney, Phillip R.; Bauer, Brint M.; Mazyck, David W.

2016-01-01

In recent years, the alteration of titanium dioxide to become visible-light-responsive (VLR) has been a major focus in the field of photocatalysis. Currently, bare titanium dioxide requires ultraviolet light for activation due to its band gap energy of 3.2 eV. Hg-vapor fluorescent light sources are used in photocatalytic oxidation (PCO) reactors to provide adequate levels of ultraviolet light for catalyst activation; these mercury-containing lamps, however, hinder the use of this PCO technology in a spaceflight environment due to concerns over crew Hg exposure. VLR-TiO2 would allow for use of ambient visible solar radiation or highly efficient visible wavelength LEDs, both of which would make PCO approaches more efficient, flexible, economical, and safe. Over the past three years, Kennedy Space Center has developed a VLR Ag-doped TiO2 catalyst with a band gap of 2.72 eV and promising photocatalytic activity. Catalyst immobilization techniques, including incorporation of the catalyst into a sorbent material, were examined. Extensive modeling of a reactor test bed mimicking air duct work with throughput similar to that seen on the International Space Station was completed to determine optimal reactor design. A bench-scale reactor with the novel catalyst and high-efficiency blue LEDs was challenged with several common volatile organic compounds (VOCs) found in ISS cabin air to evaluate the system's ability to perform high-throughput trace contaminant removal. The ultimate goal for this testing was to determine if the unit would be useful in pre-heat exchanger operations to lessen condensed VOCs in recovered water thus lowering the burden of VOC removal for water purification systems.

Phenol oxidation by a sequential CWPO-CWAO treatment with a Fe/AC catalyst.

PubMed

Quintanilla, A; Fraile, A F; Casas, J A; Rodríguez, J J

2007-07-31

Catalytic wet peroxide oxidation (CWPO) of phenol with a homemade Fe/activated carbon (Fe/AC) catalyst has been studied in a stainless steel fixed-bed reactor at different operating conditions (T=23-100 degrees C, P(T)=1-8atm, W=0-2.5g, and tau=20-320g(CAT)h/g(Phenol)). The results show that, thanks to the incorporation of Fe on the activated carbon, phenol conversion improved dramatically, reaching a 90% at 65 degrees C, 2atm, and 40g(CAT)h/g(Phenol). However, TOC conversion values remain fairly low, (around 5% at 40g(CAT)h/g(Phenol)), and no improvement was obtained with the inclusion of Fe. The presence of Fe seems to promote the nondesirable coupling reactions that take place in CWPO of phenol due to the condensation of the ring intermediates (the primary phenol oxidation products). These condensation products are quite refractory to CWPO at the conditions employed. Taking advantage of the high phenol conversions in CWPO and the high phenol mineralization in CWAO, along with the good stability of the Fe/AC catalyst, a CWPO-CWAO sequential treatment has been successfully performed by using a fixed-bed and trickle-bed reactor in series. A CWPO treatment at ambient conditions followed by a CWAO treatment at mild conditions (100 degrees C and 8atm) is presented as high efficiency process for the decontamination of phenolic wastewaters.

Influence of Alumina Binder Content on Catalytic Performance of Ni/HZSM-5 for Hydrodeoxygenation of Cyclohexanone

PubMed Central

Kong, Xiangjin; Liu, Junhai

2014-01-01

The influence of the amount of alumina binders on the catalytic performance of Ni/HZSM-5 for hydrodeoxygenation of cyclohexanone was investigated in a fixed-bed reactor. N2 sorption, X-ray diffraction, H2-chemisorption and temperature-programmed desorption of ammonia were used to characterize the catalysts. It can be observed that the Ni/HZSM-5 catalyst bound with 30 wt.% alumina binder exhibited the best catalytic performance. The high catalytic performance may be due to relatively good Ni metal dispersion, moderate mesoporosity, and proper acidity of the catalyst. PMID:25009974

Influence of alumina binder content on catalytic performance of Ni/HZSM-5 for hydrodeoxygenation of cyclohexanone.

PubMed

Kong, Xiangjin; Liu, Junhai

2014-01-01

The influence of the amount of alumina binders on the catalytic performance of Ni/HZSM-5 for hydrodeoxygenation of cyclohexanone was investigated in a fixed-bed reactor. N2 sorption, X-ray diffraction, H2-chemisorption and temperature-programmed desorption of ammonia were used to characterize the catalysts. It can be observed that the Ni/HZSM-5 catalyst bound with 30 wt.% alumina binder exhibited the best catalytic performance. The high catalytic performance may be due to relatively good Ni metal dispersion, moderate mesoporosity, and proper acidity of the catalyst.

Continuous production of lipase-catalyzed biodiesel in a packed-bed reactor: optimization and enzyme reuse study.

PubMed

Chen, Hsiao-Ching; Ju, Hen-Yi; Wu, Tsung-Ta; Liu, Yung-Chuan; Lee, Chih-Chen; Chang, Cheng; Chung, Yi-Lin; Shieh, Chwen-Jen

2011-01-01

An optimal continuous production of biodiesel by methanolysis of soybean oil in a packed-bed reactor was developed using immobilized lipase (Novozym 435) as a catalyst in a tert-butanol solvent system. Response surface methodology (RSM) and Box-Behnken design were employed to evaluate the effects of reaction temperature, flow rate, and substrate molar ratio on the molar conversion of biodiesel. The results showed that flow rate and temperature have significant effects on the percentage of molar conversion. On the basis of ridge max analysis, the optimum conditions were as follows: flow rate 0.1 mL/min, temperature 52.1°C, and substrate molar ratio 1 : 4. The predicted and experimental values of molar conversion were 83.31 ± 2.07% and 82.81 ± .98%, respectively. Furthermore, the continuous process over 30 days showed no appreciable decrease in the molar conversion. The paper demonstrates the applicability of using immobilized lipase and a packed-bed reactor for continuous biodiesel synthesis.

Catalytic oxidation of toluene: comparative study over powder and monolithic manganese-nickel mixed oxide catalysts.

PubMed

Duplančić, Marina; Tomašić, Vesna; Gomzi, Zoran

2017-07-05

This paper is focused on development of the metal monolithic structure for total oxidation of toluene at low temperature. The well-adhered catalyst, based on the mixed oxides of manganese and nickel, is washcoated on the Al/Al 2 O 3 plates as metallic support. For the comparison purposes, results observed for the manganese-nickel mixed oxide supported on the metallic monolith are compared with those obtained using powder type of the same catalyst. Prepared manganese-nickel mixed oxides in both configurations show remarkable low-temperature activity for the toluene oxidation. The reaction temperature T 50 corresponding to 50% of the toluene conversion is observed at temperatures of ca. 400-430 K for the powder catalyst and at ca. 450-490 K for the monolith configuration. The appropriate mathematical models, such as one-dimensional (1D) pseudo-homogeneous model of the fixed bed reactor and the 1D heterogeneous model of the metal monolith reactor, are applied to describe and compare catalytic performances of both reactors. Validation of the applied models is performed by comparing experimental data with theoretical predictions. The obtained results confirmed that the reaction over the monolithic structure is kinetically controlled, while in the case of the powder catalyst the reaction rate is influenced by the intraphase diffusion.

Improvements in Production of Single-Walled Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Balzano, Leandro; Resasco, Daniel E.

2009-01-01

A continuing program of research and development has been directed toward improvement of a prior batch process in which single-walled carbon nanotubes are formed by catalytic disproportionation of carbon monoxide in a fluidized-bed reactor. The overall effect of the improvements has been to make progress toward converting the process from a batch mode to a continuous mode and to scaling of production to larger quantities. Efforts have also been made to optimize associated purification and dispersion post processes to make them effective at large scales and to investigate means of incorporating the purified products into composite materials. The ultimate purpose of the program is to enable the production of high-quality single-walled carbon nanotubes in quantities large enough and at costs low enough to foster the further development of practical applications. The fluidized bed used in this process contains mixed-metal catalyst particles. The choice of the catalyst and the operating conditions is such that the yield of single-walled carbon nanotubes, relative to all forms of carbon (including carbon fibers, multi-walled carbon nanotubes, and graphite) produced in the disproportionation reaction is more than 90 weight percent. After the reaction, the nanotubes are dispersed in various solvents in preparation for end use, which typically involves blending into a plastic, ceramic, or other matrix to form a composite material. Notwithstanding the batch nature of the unmodified prior fluidized-bed process, the fluidized-bed reactor operates in a continuous mode during the process. The operation is almost entirely automated, utilizing mass flow controllers, a control computer running software specific to the process, and other equipment. Moreover, an important inherent advantage of fluidized- bed reactors in general is that solid particles can be added to and removed from fluidized beds during operation. For these reasons, the process and equipment were amenable to modification for conversion from batch to continuous production.

Application and Discussion of Dual Fluidized Bed Reactor in Biomass Energy Utilization

NASA Astrophysics Data System (ADS)

Guan, Haibin; Fan, Xiaoxu; Zhao, Baofeng; Yang, Liguo; Sun, Rongfeng

2018-01-01

As an important clean and renewable energy, biomass has a broad market prospect. The dual fluidized bed is widely used in biomass gasification technology, and has become an important way of biomass high-value utilization. This paper describes the basic principle of dual fluidized bed gasification, from the gas composition, tar content and thermal efficiency of the system point of view, analyzes and summarizes several typical dual fluidized bed biomass gasification technologies, points out the existence of gas mixing, the external heat source, catalyst development problems on gas. Finally, it is clear that the gasification of biomass in dual fluidized bed is of great industrial application and development prospect.

Method of synthesizing bulk transition metal carbide, nitride and phosphide catalysts

DOEpatents

Choi, Jae Soon; Armstrong, Beth L; Schwartz, Viviane

2015-04-21

A method for synthesizing catalyst beads of bulk transmission metal carbides, nitrides and phosphides is provided. The method includes providing an aqueous suspension of transition metal oxide particles in a gel forming base, dropping the suspension into an aqueous solution to form a gel bead matrix, heating the bead to remove the binder, and carburizing, nitriding or phosphiding the bead to form a transition metal carbide, nitride, or phosphide catalyst bead. The method can be tuned for control of porosity, mechanical strength, and dopant content of the beads. The produced catalyst beads are catalytically active, mechanically robust, and suitable for packed-bed reactor applications. The produced catalyst beads are suitable for biomass conversion, petrochemistry, petroleum refining, electrocatalysis, and other applications.

CATALYTIC HYDRODECHLORINATION OF 1,3-DICHLOROPROPENE. (R826694C626)

EPA Science Inventory

The hydrodechlorination reactions of 1,3-dichloropropene, a component of the waste stream from epichlorohydrin manufacturing, were examined over a variety of catalysts in a packed-bed microreactor. The reactor operated between 7.5–9 Mpa and 325°C and rates of ...

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The objective of Task I is to prepare and evaluate catalysts and to develop efficient reactor systems for the selective conversion of hydrogen-lean synthesis gas to alcohol fuel extenders and octane enhancers. In Task 1, during this reporting period, we encountered and solved a problem in the analysis of the reaction products containing a small amount of heavy components. Subsequently, we continued with the major thrusts of the program. We analyzed the results from our preliminary studies on the packed-bed membrane reactor using the BASF methanol synthesis catalyst. We developed a quantitative model to describe the performance of the reactor.more » The effect of varying permeances and the effect of catalyst aging are being incorporated into the model. Secondly, we resumed our more- detailed parametric studies on selected non-sulfide Mo-based catalysts. Finally, we continue with the analysis of data from the kinetic study of a sulfided carbon-supported potassium-doped molybdenum-cobalt catalyst in the Rotoberty reactor. We have completed catalyst screening at UCC. The complete characterization of selected catalysts has been started. In Task 2, the fuel blends of alcohol and unleaded test gas 96 (UTG 96) have been made and tests have been completed. The testing includes knock resistance tests and emissions tests. Emissions tests were conducted when the engine was optimized for the particular blend being tested (i.e. where the engine produced the most power when running on the blend in question). The data shows that the presence of alcohol in the fuel increases the fuel`s ability to resist knock. Because of this, when the engine was optimized for use with alcohol blends, the engine produced more power and lower emission rates.« less

Catalytic Destruction of Chlorinated Volatile Organic Compounds

DTIC Science & Technology

1993-08-01

Figure 1. The glass reactor passed through two furnaces. Both the furnaces were Lindberg 55035 hinged tube type. The top furnace served the purpose...10. HC1 Scrubber 10 11 12 11 13 11. Thermocouples 12. Manometer Tap 13. Glass Wool Figure 1. Schematic of the Reactor were used to check the...In the case of catalyst pellets, a thin layer of glass wool was used to hold the bed in place. The chlorinated hydrocarbon feed was introduced into

Biomass-derived Syngas Utilization for Fuels and Chemicals - Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dayton, David C

2010-03-24

Executive Summary The growing gap between petroleum production and demand, mounting environmental concerns, and increasing fuel prices have stimulated intense interest in research and development (R&D) of alternative fuels, both synthetic and bio-derived. Currently, the most technically defined thermochemical route for producing alternative fuels from lignocellulosic biomass involves gasification/reforming of biomass to produce syngas (carbon monoxide [CO] + hydrogen [H2]), followed by syngas cleaning, Fischer-Tropsch synthesis (FTS) or mixed alcohol synthesis, and some product upgrading via hydroprocessing or separation. A detailed techno-economic analysis of this type of process has recently been published [1] and it highlights the need for technicalmore » breakthroughs and technology demonstration for gas cleanup and fuel synthesis. The latter two technical barrier areas contribute 40% of the total thermochemical ethanol cost and 70% of the production cost, if feedstock costs are factored out. Developing and validating technologies that reduce the capital and operating costs of these unit operations will greatly reduce the risk for commercializing integrated biomass gasification/fuel synthesis processes for biofuel production. The objective of this project is to develop and demonstrate new catalysts and catalytic processes that can efficiently convert biomass-derived syngas into diesel fuel and C2-C4 alcohols. The goal is to improve the economics of the processes by improving the catalytic activity and product selectivity, which could lead to commercialization. The project was divided into 4 tasks: Task 1: Reactor Systems: Construction of three reactor systems was a project milestone. Construction of a fixed-bed microreactor (FBR), a continuous stirred tank reactor (CSTR), and a slurry bubble column reactor (SBCR) were completed to meet this milestone. Task 2: Iron Fischer-Tropsch (FT) Catalyst: An attrition resistant iron FT catalyst will be developed and tested. Task 3: Chemical Synthesis: Promising process routes will be identified for synthesis of selected chemicals from biomass-derived syngas. A project milestone was to select promising mixed alcohol catalysts and screen productivity and performance in a fixed bed micro-reactor using bottled syngas. This milestone was successfully completed in collaboration withour catalyst development partner. Task 4: Modeling, Engineering Evaluation, and Commercial Assessment: Mass and energy balances of conceptual commercial embodiment for FT and chemical synthesis were completed.« less

Oxygenates vs. synthesis gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamil Klier; Richard G. Herman; Alessandra Beretta

1999-04-01

Methanol synthesis from H{sub 2}/CO has been carried out at 7.6 MPa over zirconia-supported copper catalysts. Catalysts with nominal compositions of 10/90 mol% and 30/70 mol% Cu/ZrO{sub 2} were used in this study. Additionally, a 3 mol% cesium-doped 10/90 catalyst was prepared to study the effect of doping with heavy alkali, and this promoter greatly increased the methanol productivity. The effects of CO{sub 2} addition, water injection, reaction temperature, and H{sub 2}/C0 ratio have been investigated. Both CO{sub 2} addition to the synthesis gas and cesium doping of the catalyst promoted methanol synthesis, while inhibiting the synthesis of dimethyl ether.more » Injection of water, however, was found to slightly suppress methanol and dimethyl ether formation while being converted to CO{sub 2} via the water gas shift reaction over these catalysts. There was no clear correlation between copper surface area and catalyst activity. Surface analysis of the tested samples revealed that copper tended to migrate and enrich the catalyst surface. The concept of employing a double-bed reactor with a pronounced temperature gradient to enhance higher alcohol synthesis was explored, and it was found that utilization of a Cs-promoted Cu/ZnO/Cr{sub 2}O{sub 3} catalyst as a first lower temperature bed and a Cs-promoted ZnO/Cr{sub 2}O{sub 3} catalyst as a second high-temperature bed significantly promoted the productivity of 2-methyl-1-propanol (isobutanol) from H{sub 2}/CO synthesis gas mixtures. While the conversion of CO to C{sub 2+} oxygenates over the double-bed configuration was comparable to that observed over the single Cu-based catalyst, major changes in the product distribution occurred by the coupling to the zinc chromite catalyst; that is, the productivity of the C{sub 1}-C{sub 3} alcohols decreased dramatically, and 2-methyl branched alcohols were selectively formed. The desirable methanol/2-methyl oxygenate molar ratios close to 1 were obtained in the present double-bed system that provides the feedstock for the synthesis of high octane and high cetane ethers, where the isobutanol productivity was as high as 139 g/kg cat/hr. Higher alcohol synthesis has been investigated over a Cs/Cu/ZnO/Cr{sub 2}O{sub 3} catalyst at temperatures higher (up to 703K) than those previously utilized, and no sintering of the catalyst was observed during the short-term testing. However, the higher reaction temperatures led to lower CO conversion levels and lower yield of alcohols, especially of methanol, because of equilibrium limitations. With the double catalyst bed configuration, the effect of pressure in the range of 7.6--12.4 MPa on catalyst activity and selectivity was studied. The upper bed was composed of the copper-based catalyst at 598K, and the lower bed consisted of a copper-free Cs-ZnO/Cr{sub 2}O{sub 3} catalyst at a high temperature of 678K. High pressure was found to increase CO conversion to oxygenated products, although the increase in isobutanol productivity did not keep pace with that of methanol. It was also shown that the Cs/Cu/ZnO/Cr{sub 2}O{sub 3} catalyst could be utilized to advantage as the second-bed catalyst at 613--643K instead of the previously used copper-free Cs-ZnO/ Cr{sub 2}O{sub 3} catalyst at higher temperature, With double Cs/Cu/ZnO/Cr{sub 2}O{sub 3} catalysts, high space time yields of up to 202 g/kg cat/hr, with high selectivity to isobutanol, were achieved.« less

Producing Hydrogen by Plasma Pyrolysis of Methane

NASA Technical Reports Server (NTRS)

Atwater, James; Akse, James; Wheeler, Richard

2010-01-01

Plasma pyrolysis of methane has been investigated for utility as a process for producing hydrogen. This process was conceived as a means of recovering hydrogen from methane produced as a byproduct of operation of a life-support system aboard a spacecraft. On Earth, this process, when fully developed, could be a means of producing hydrogen (for use as a fuel) from methane in natural gas. The most closely related prior competing process - catalytic pyrolysis of methane - has several disadvantages: a) The reactor used in the process is highly susceptible to fouling and deactivation of the catalyst by carbon deposits, necessitating frequent regeneration or replacement of the catalyst. b) The reactor is highly susceptible to plugging by deposition of carbon within fixed beds, with consequent channeling of flow, high pressure drops, and severe limitations on mass transfer, all contributing to reductions in reactor efficiency. c) Reaction rates are intrinsically low. d) The energy demand of the process is high.

Autothermal reforming of propane over Mg-Al hydrotalcite-like catalysts.

PubMed

Lim, You-Soon; Park, Nam-Cook; Shin, Jae-Soon; Kim, Jong-Ho; Moon, Dong-Ju; Kim, Young-Chul

2008-10-01

The performance of hydrotalcite-like catalysts in propane autothermal reforming for hydrogen production was studied in fixed-bed flow reactor. Hydrotalcite-like catalysts were synthesized by coprecipitation and modified co-precipitation by the impregnation method and those were promoted by the addition of noble metals. Reaction test results indicated that hydrotalcite-like catalysts of modified method were showed higher H2-yield than co-precipitation method because surface Ni particles of catalysts by modified method were more abundant. When added noble metals, the activity was enhanced because the size of nickel particles was decreased and degree of dispersion was increased. Also the carbon deposit is low after the reaction. When solvent of solution was changed, activity was increased. It is because degree of dispersion was increased.

Demonstrating the Effect of Interphase Mass Transfer in a Transparent Fluidized Bed Reactor

ERIC Educational Resources Information Center

Saayman, Jean; Nicol, Willie

2011-01-01

A demonstration experiment is described that employs the ozone decomposition reaction at ambient conditions on Fe2O3 impregnated Fluidized Catalytic Cracking (FCC) catalyst. Using a two-dimensional see-through column the importance of interphase mass transfer is clearly illustrated by the significant difference in ozone conversion between the…

Catalysts for synthesizing various short chain hydrocarbons

DOEpatents

Colmenares, Carlos

1991-01-01

Method and apparatus (10), including novel photocatalysts, are disclosed for the synthesis of various short chain hydrocarbons. Light-transparent SiO.sub.2 aerogels doped with photochemically active uranyl ions (18) are fluidized in a fluidized-bed reactor (12) having a transparent window (16), by hydrogen and CO, C.sub.2 H.sub.4 or C.sub.2 H.sub.6 gas mixtures (20), and exposed to radiation (34) from a light source (32) external to the reactor (12), to produce the short chain hydrocarbons (36).

Contact structure for use in catalytic distillation

DOEpatents

Jones, E.M. Jr.

1984-03-27

A method is described for conducting catalytic chemical reactions and fractionation of the reaction mixture comprising feeding reactants into a distillation column reactor, contracting said reactant in liquid phase with a fixed bed catalyst in the form of a contact catalyst structure consisting of closed porous containers containing the catalyst for the reaction and a clip means to hold and support said containers, which are disposed above, i.e., on the distillation trays in the tower. The trays have weir means to provide a liquid level on the trays to substantially cover the containers. In other words, the trays function in their ordinary manner with the addition thereto of the catalyst. The reaction mixture is concurrently fractionated in the column. 7 figs.

Contact structure for use in catalytic distillation

DOEpatents

Jones, Jr., Edward M.

1985-01-01

A method and apparatus for conducting catalytic chemical reactions and fractionation of the reaction mixture, comprising and feeding reactants into a distillation column reactor contracting said reactant in a liquid phase with a fixed bed catalyst in the form of a contact catalyst structure, consisting of closed porous containers containing the catalyst for the reaction and a clip means to hold and support said containers, which are disposed above, i.e., on the distillation trays in the tower. The trays have weir means to provide a liquid level on the trays to substantially cover the containers. In other words, the trays function in their ordinary manner with the addition thereto of the catalyst. The reaction mixture is concurrently fractionated in the column.

Contact structure for use in catalytic distillation

DOEpatents

Jones, E.M. Jr.

1985-08-20

A method and apparatus are disclosed for conducting catalytic chemical reactions and fractionation of the reaction mixture, comprising and feeding reactants into a distillation column reactor contracting said reactant in a liquid phase with a fixed bed catalyst in the form of a contact catalyst structure, consisting of closed porous containers containing the catalyst for the reaction and a clip means to hold and support said containers, which are disposed above, i.e., on the distillation trays in the tower. The trays have weir means to provide a liquid level on the trays to substantially cover the containers. In other words, the trays function in their ordinary manner with the addition thereto of the catalyst. The reaction mixture is concurrently fractionated in the column. 7 figs.

Kinetics of resid hydrodesulfurization reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohammed, A.H.A.K.; Abbas, A.A.A.; Al'-Maiya, A.S.K.

1987-07-01

In this article the authors examine the results obtained in hydrodesulfurizing an atmospheric resis from Bai-Hassan crude on Ni-Mo/Al/sub 2/O/sub 3/ catalyst at 320-420/sup 0/C, feedstock space velocity 0.37-2.6 h/sup -1/, pressure 6.1 MPa, and hydrogen/feed ratio 300 liters/liter, in a single-pass downflow reactor with a stationary bed of catalyst. Also, they give certain thermodynamic characteristics for desulfurization, demetalization, and deasphalting of this resid. The kinetic model describing most accurately the kinetics of the different reactions will be examined.

Attrition resistant fluidizable reforming catalyst

DOEpatents

Parent, Yves O [Golden, CO; Magrini, Kim [Golden, CO; Landin, Steven M [Conifer, CO; Ritland, Marcus A [Palm Beach Shores, FL

2011-03-29

A method of preparing a steam reforming catalyst characterized by improved resistance to attrition loss when used for cracking, reforming, water gas shift and gasification reactions on feedstock in a fluidized bed reactor, comprising: fabricating the ceramic support particle, coating a ceramic support by adding an aqueous solution of a precursor salt of a metal selected from the group consisting of Ni, Pt, Pd, Ru, Rh, Cr, Co, Mn, Mg, K, La and Fe and mixtures thereof to the ceramic support and calcining the coated ceramic in air to convert the metal salts to metal oxides.

Direct synthesis of ethanol from dimethyl ether and syngas over combined H-Mordenite and Cu/ZnO catalysts.

PubMed

Li, Xingang; San, Xiaoguang; Zhang, Yi; Ichii, Takashi; Meng, Ming; Tan, Yisheng; Tsubaki, Noritatsu

2010-10-25

Ethanol was directly synthesized from dimethyl ether (DME) and syngas with the combined H-Mordenite and Cu/ZnO catalysts that were separately loaded in a dual-catalyst bed reactor. Methyl acetate (MA) was formed by DME carbonylation over the H-Mordenite catalyst. Thereafter, ethanol and methanol were produced by MA hydrogenation over the Cu/ZnO catalyst. With the reactant gas containing 1.0% DME, the optimized temperature for the reaction was at 493 K to reach 100% conversion. In the products, the yield of methanol and ethanol could reach 46.3% and 42.2%, respectively, with a small amount of MA, ethyl acetate, and CO(2). This process is environmentally friendly as the main byproduct methanol can be recycled to DME by a dehydration reaction. In contrast, for the physically mixed catalysts, the low conversion of DME and high selectivity of methanol were observed.

Methods for natural gas and heavy hydrocarbon co-conversion

DOEpatents

Kong, Peter C [Idaho Falls, ID; Nelson, Lee O [Idaho Falls, ID; Detering, Brent A [Idaho Falls, ID

2009-02-24

A reactor for reactive co-conversion of heavy hydrocarbons and hydrocarbon gases and includes a dielectric barrier discharge plasma cell having a pair of electrodes separated by a dielectric material and passageway therebetween. An inlet is provided for feeding heavy hydrocarbons and other reactive materials to the passageway of the discharge plasma cell, and an outlet is provided for discharging reaction products from the reactor. A packed bed catalyst may optionally be used in the reactor to increase efficiency of conversion. The reactor can be modified to allow use of a variety of light sources for providing ultraviolet light within the discharge plasma cell. Methods for upgrading heavy hydrocarbons are also disclosed.

Nonthermal plasma systems and methods for natural gas and heavy hydrocarbon co-conversion

DOEpatents

Kong, Peter C.; Nelson, Lee O.; Detering, Brent A.

2005-05-24

A reactor for reactive co-conversion of heavy hydrocarbons and hydrocarbon gases and includes a dielectric barrier discharge plasma cell having a pair of electrodes separated by a dielectric material and passageway therebetween. An inlet is provided for feeding heavy hydrocarbons and other reactive materials to the passageway of the discharge plasma cell, and an outlet is provided for discharging reaction products from the reactor. A packed bed catalyst may optionally be used in the reactor to increase efficiency of conversion. The reactor can be modified to allow use of a variety of light sources for providing ultraviolet light within the discharge plasma cell. Methods for upgrading heavy hydrocarbons are also disclosed.

Activity of Cu-activated carbon fiber catalyst in wet oxidation of ammonia solution.

PubMed

Hung, Chang-Mao

2009-07-30

Aqueous solutions of 200-1000 mg/L of ammonia were oxidized in a trickle-bed reactor using Cu-activated carbon fiber (ACF) catalysts, which were prepared by incipient wet impregnation with aqueous solutions of copper nitrate that was deposited on ACF substrates. The results reveal that the conversion of ammonia by wet oxidation in the presence of Cu-ACF catalysts was a function of the metal loading weight ratio of the catalyst. The total conversion efficiency of ammonia was 95% during wet oxidation over the catalyst at 463 K at an oxygen partial pressure of 3.0 MPa. Moreover, the effect of the initial concentration of ammonia and the reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid space velocity of less than 3.0 h(-1).

Adsorption and oxidation of SO₂in a fixed-bed reactor using activated carbon produced from oxytetracycline bacterial residue and impregnated with copper.

PubMed

Zhou, Baohua; Yu, Lei; Song, Hanning; Li, Yaqi; Zhang, Peng; Guo, Bin; Duan, Erhong

2015-02-01

The SO₂removal ability (including adsorption and oxidation ability) of activated carbon produced from oxytetracycline bacterial residue and impregnated with copper was investigated. The activated carbon produced from oxytetracycline bacterial residue and modified with copper was characterized by x-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The effects of the catalysts, SO₂concentration, weight hourly space velocity, and temperature on the SO₂adsorption and oxidation activity were evaluated. Activated carbon produced from oxytetracycline bacterial residue and used as catalyst supports for copper oxide catalysts provided high catalytic activity for the adsorbing and oxidizing of SO₂from flue gases.

Contact structure for use in catalytic distillation

DOEpatents

Jones, Jr., Edward M.

1984-01-01

A method for conducting catalytic chemical reactions and fractionation of the reaction mixture comprising feeding reactants into a distillation column reactor contracting said reactant in liquid phase with a fixed bed catalyst in the form of a contact catalyst structure consisting of closed porous containers containing the catatlyst for the reaction and a clip means to hold and support said containers, which are disposed above, i.e., on the distillation trays in the tower. The trays have weir means to provide a liquid level on the trays to substantially cover the containers. In other words, the trays function in their ordinary manner with the addition thereto of the catalyst. The reaction mixture is concurrently fractionated in the column.

Enhanced Oxidation Catalysts for Water Reclamation

NASA Technical Reports Server (NTRS)

Jolly, Clifford D.

1999-01-01

This effort seeks to develop and test high-performance, long operating life, physically stable catalysts for use in spacecraft water reclamation systems. The primary goals are to a) reduce the quantity of expendable water filters used to purify water aboard spacecraft, b) to extend the life of the oxidation catalysts used for eliminating organic contaminants in the water reclamation systems, and c) reduce the weight/volume of the catalytic oxidation systems (e.g. VRA) used. This effort is targeted toward later space station utilization and will consist of developing flight-qualifiable catalysts and long-term ground tests of the catalyst prior to their utilization in flight. Fixed -bed catalytic reactors containing 5% platinum on granular activated carbon have been subjected to long-term dynamic column tests to measure catalyst stability vs throughput. The data generated so far indicate that an order of magnitude improvement can be obtained with the treated catalysts vs the control catalyst, at only a minor loss (approx 10%) in the initial catalytic activity.

CATALYTIC RECOMBINER FOR A NUCLEAR REACTOR

DOEpatents

King, L.D.P.

1960-07-01

A hydrogen-oxygen recombiner is described for use with water-boiler type reactors. The catalyst used is the wellknown platinized alumina, and the novelty lies in the structural arrangement used to prevent flashback through the gas input system. The recombiner is cylindrical, the gases at the input end being deflected by a baffle plate through a first flashback shield of steel shot into an annular passage adjacent to and extending the full length of the housing. Below the baffle plate the gases flow first through an outer annular array of alumina pellets which serve as a second flashback shield, a means of distributing the flowing gases evenly and as a means of reducing radiation losses to the walls. Thereafter the gases flow inio the centrally disposed catalyst bed where recombination is effected. The steam and uncombined gases flow into a centrally disposed cylindrical passage inside the catalyst bod and thereafter out through the exit port. A high rate of recombination is effected.

Catalytic pyrolysis of black-liquor lignin by co-feeding with different plastics in a fluidized bed reactor.

PubMed

Zhang, Huiyan; Xiao, Rui; Nie, Jianlong; Jin, Baosheng; Shao, Shanshan; Xiao, Guomin

2015-09-01

Catalytic co-pyrolysis of black-liquor lignin and waste plastics (polyethylene, PE; polypropylene PP; polystyrene, PS) was conducted in a fluidized bed. The effects of temperature, plastic to lignin ratio, catalyst and plastic types on product distributions were studied. Both aromatic and olefin yields increased with increasing PE proportion. Petrochemical yield of co-pyrolysis of PE and lignin was LOSA-1 > spent FCC > Gamma-Al2O3 > sand. The petrochemical yield with LOSA-1 is 43.9% which is more than two times of that without catalyst. The feedstock for co-pyrolysis with lignin is polystyrene > polyethylene > polypropylene. Catalytic co-pyrolysis of black-liquor lignin with PS produced the maximum aromatic yield (55.3%), while co-pyrolysis with PE produced the maximum olefin yield (13%). Copyright © 2015 Elsevier Ltd. All rights reserved.

Self-Cleaning Boudouard Reactor for Full Oxygen Recovery from CO2 Project

NASA Technical Reports Server (NTRS)

Zeitlin, Nancy; Muscatello, Anthony

2015-01-01

Oxygen recovery from respiratory CO2 is an important aspect of human spaceflight. Methods exist to sequester the CO2, but production of oxygen needs further development. The current ISS Carbon Dioxide Reduction System (CRS) uses the Sabatier reaction to produce water (and ultimately breathing air). Oxygen recovery is limited to 50% because half of the hydrogen used in the Sabatier reactor is lost as methane, which is vented overboard. The Bosch reaction is the only real alternative to the Sabatier reaction, but in the last reaction in the cycle (Boudouard) the resulting carbon buildup will eventually foul the nickel or iron catalyst, reducing reactor life and increasing consumables. To minimize this fouling, find a use for this waste product, and increase efficiency, we propose testing various self-cleaning catalyst designs in an existing MSFC Boudouard reaction test bed and to determine which one is the most reliable in conversion and lack of fouling. Challenges include mechanical reliability of the cleaning method and maintaining high conversion efficiency with lower catalyst surface area. The above chemical reactions are well understood, but planned implementations are novel (TRL 2) and haven't been investigated at any level.

Catalytic Production of Ethanol from Biomass-Derived Synthesis Gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trewyn, Brian G.; Smith, Ryan G.

2016-06-01

Heterogeneous catalysts have been developed for the conversion of biomass-derived synthetic gas (syngas) to ethanol. The objectives of this project were to develop a clean synthesis gas from biomass and develop robust catalysts with high selectivity and lifetime for C 2 oxygenate production from biomass-derived syngas and surrogate syngas. During the timeframe for this project, we have made research progress on the four tasks: (1) Produce clean bio-oil generated from biomass, such as corn stover or switchgrass, by using fast pyrolysis system, (2) Produce clean, high pressure synthetic gas (syngas: carbon monoxide, CO, and hydrogen, H 2) from bio-oil generatedmore » from biomass by gasification, (3) Develop and characterize mesoporous mixed oxide-supported metal catalysts for the selective production of ethanol and other alcohols, such as butanol, from synthesis gas, and (4) Design and build a laboratory scale synthesis gas to ethanol reactor system evaluation of the process. In this final report, detailed explanations of the research challenges associated with this project are given. Progress of the syngas production from various biomass feedstocks and catalyst synthesis for upgrading the syngas to C 2-oxygenates is included. Reaction properties of the catalyst systems under different reaction conditions and different reactor set-ups are also presented and discussed. Specifically, the development and application of mesoporous silica and mesoporous carbon supports with rhodium nanoparticle catalysts and rhodium nanoparticle with manganese catalysts are described along with the significant material characterizations we completed. In addition to the synthesis and characterization, we described the activity and selectivity of catalysts in our micro-tubular reactor (small scale) and fixed bed reactor (larger scale). After years of hard work, we are proud of the work done on this project, and do believe that this work will provide a solid foundation for the future production of syngas from biomass and the development of heterogeneous catalysts for the syngas to C 2-oxygenate process and for the commercialization of this process. Potential future directions for this research are also discussed within the report.« less

Tri-reforming of surrogate blogs over Ni/Mg/ceria-zirconia/alumina pellet catalysts

DOE PAGES

Zhao, Xianhui; Ngo, Huong T.; Walker, Devin M.; ...

2018-01-23

The performance of catalytic tri-reforming under industrially relevant situations (e.g., pellet catalysts, pressurized reactor) was investigated using surrogate biogas as the feedstock. Tri-reforming using Ni/Mg/Ce 0.6Zr 0.4O 2/Al 2O 3 pellet catalysts was studied in a bench scale fixed-bed reactor. The feed molar ratio for CH 4: CO 2: air was fixed as 1.0: 0.70: 0.95. The effects of temperature (800 – 860 °C), pressure (1 – 6 bar), and H 2O/CH 4 molar feed ratio (0.23 – 0.65) were examined. Pressure has substantial impact on the reaction and transport rates and equilibrium conversions, making it a key variable. Atmore » 860 °C, CO 2 conversion increased from 4 to 61% and H 2/CO molar ratio decreased from 2.0 to 1.1 as the pressure changed from 1 to 6 bar. CO 2 conversion and H 2/CO molar ratio were also influenced by the temperature and H 2O/CH 4 molar ratio. At 3 bar, CO 2 conversion varied between 4 and 43% and the H 2/CO molar ratio varied between 1.2 and 1.9 as the temperature changed from 800 to 860 °C. At 3 bar and 860 °C, CO 2 conversion decreased from 35 to 8% and H 2/CO molar ratio increased from 1.7 to 2.4 when the H 2O/CH 4 molar ratio was increased from 0.23 to 0.65. This work demonstrates that the tri-reforming technology is feasible for converting biogas under scaled-up conditions in a fixed-bed reactor.« less

Attrition Resistant Fischer-Tropsch Catalysts Based on FCC Supports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adeyiga, Adeyinka

2010-02-05

Commercial spent fluid catalytic cracking (FCC) catalysts provided by Engelhard and Albemarle were used as supports for Fe-based catalysts with the goal of improving the attrition resistance of typical F-T catalysts. Catalysts with the Ruhrchemie composition (100 Fe/5 Cu/4.2 K/25 spent FCC on mass basis) were prepared by wet impregnation. XRD and XANES analysis showed the presence of Fe{sub 2}O{sub 3} in calcined catalysts. FeC{sub x} and Fe{sub 3}O{sub 4} were present in the activated catalysts. The metal composition of the catalysts was analyzed by ICP-MS. F-T activity of the catalysts activated in situ in CO at the same conditionsmore » as used prior to the attrition tests was measured using a fixed bed reactor at T = 573 K, P = 1.38 MPa and H{sub 2}:CO ratio of 0.67. Cu and K promoted Fe supported over Engelhard provided spent FCC catalyst shows relatively good attrition resistance (8.2 wt% fines lost), high CO conversion (81%) and C{sub 5}+ hydrocarbons selectivity (18.3%).« less

Pyrolysis of marine biomass to produce bio-oil and its upgrading using a novel multi-metal catalyst prepared from the spent car catalytic converter.

PubMed

Sabegh, Mahzad Yaghmaei; Norouzi, Omid; Jafarian, Sajedeh; Khosh, Akram Ghanbari; Tavasoli, Ahmad

2018-02-01

In order to reduce the economic and environmental consequences caused by spent car catalyst, we herein report for the first time a novel promising multi-metal catalyst prepared from spent car catalytic converters to upgrade the pyrolysis bio-oils. The physico-chemical properties of prepared catalyst were characterized by XRD, EDS, FESEM, and FT-IR analyses. The thermal stability of the multi-metal catalyst was studied with TGA. To investigate the activity of the catalyst, Conversion of Cladophora glomerata (C. glomerata) into bio-products was carried out via a fixed bed reactor with and without catalyst at the temperature of 500°C. Although the catalyst didn't catalyze the gasification reaction, bio-oil was upgraded over the catalyst. The main effect of the catalyst on the bio-oil components is deoxygenating of nitrogen compounds and promotion the ketonization reaction, which converts acid to ketone and declines the corrosive nature of bio-oil. Copyright © 2017. Published by Elsevier Ltd.

Advanced reactors and novel reactions for the conversion of triglyceride based oils into high quality renewable transportation fuels

NASA Astrophysics Data System (ADS)

Linnen, Michael James

Sustainable energy continues to grow more important to all societies, leading to the research and development of a variety of alternative and renewable energy technologies. Of these, renewable liquid transportation fuels may be the most visible to consumers, and this visibility is further magnified by the long-term trend of increasingly expensive petroleum fuels that the public consumes. While first-generation biofuels such as biodiesel and fuel ethanol have been integrated into the existing fuel infrastructures of several countries, the chemical differences between them and their petroleum counterparts reduce their effectiveness. This gives rise to the development and commercialization of second generation biofuels, many of which are intended to have equivalent properties to those of their petroleum counterparts. In this dissertation, the primary reactions for a second-generation biofuel process, known herein as the University of North Dakota noncatalytic cracking process (NCP), have been studied at the fundamental level and improved. The NCP is capable of producing renewable fuels and chemicals that are virtually the same as their petroleum counterparts in performance and quality (i.e., petroleum-equivalent). In addition, a novel analytical method, FIMSDIST was developed which, within certain limitations, can increase the elution capabilities of GC analysis and decrease sample processing times compared to other high resolution methods. These advances are particularly useful for studies of highly heterogeneous fuel and/or organic chemical intermediates, such as those studied for the NCP. However the data from FIMSDIST must be supplemented with data from other methods such as for certain carboxylic acid, to provide accurate, comprehensive results, From a series of TAG cracking experiments that were performed, it was found that coke formation during cracking is most likely the result of excessive temperature and/or residence time in a cracking reactor. Based on this, a tubular cracking reactor was developed that could operate continuously without coke formation. The design also was proven to be scalable. Yields from the reactor were determined under a variety of conditions in order to predict the outputs from the NCP and to establish relationships/correlations between operating parameters and the product distribution. These studies led to the conclusion that the most severe operating conditions which do not induce coking are optimal over the experimental domain. In order to develop economical deoxygenation catalysts for use within the NCP, a series of experiments were performed using nickel catalysts, demonstrating that nickel catalysts could outperform their predecessor, a high cost palladium-based catalyst. A nickel catalyst was then tested in a packed bed reactor in order to determine suitable operating conditions for its commercial utilization in packed bed reactors.

In situ magnetic resonance measurement of conversion, hydrodynamics and mass transfer during single- and two-phase flow in fixed-bed reactors.

PubMed

Gladden, L F; Alexander, P; Britton, M M; Mantle, M D; Sederman, A J; Yuen, E H L

2003-01-01

In recent years there has been increasing interest in applying magnetic resonance (MR) techniques in areas of engineering and chemical technology. The science that underpins many of these applications is the physics and chemistry of transport and reaction processes in porous materials. Key to the exploitation of MR methods will be our ability to demonstrate that MR yields information that cannot be obtained using conventional measurement techniques in engineering research. This article describes two case studies that highlight the power of MR to give new insights to chemical engineers. First, we demonstrate the application of MR techniques to explore both mass transfer and chemical conversion in situ within a fixed bed of catalyst, and we then use these data to identify the rate-controlling step of the chemical conversion. Second, we implement a rapid imaging technique to study the stability of the gas-liquid distribution in the low- and high-interaction two-phase flow regimes in a trickle-bed reactor.

High-Flux, High Performance H2O2 Catalyst Bed for ISTAR

NASA Technical Reports Server (NTRS)

Ponzo, J.

2005-01-01

On NASA's ISTAR RBCC program packaging and performance requirements exceeded traditional H2O2 catalyst bed capabilities. Aerojet refined a high performance, monolithic 90% H202 catalyst bed previously developed and demonstrated. This approach to catalyst bed design and fabrication was an enabling technology to the ISTAR tri-fluid engine. The catalyst bed demonstrated 55 starts at throughputs greater than 0.60 lbm/s/sq in for a duration of over 900 seconds in a physical envelope approximately 114 of traditional designs. The catalyst bed uses photoetched plates of metal bonded into a single piece monolithic structure. The precise control of the geometry and complete mixing results in repeatable, quick starting, high performing catalyst bed. Three different beds were designed and tested, with the best performing bed used for tri-fluid engine testing.

Complexity and Challenges in Noncontact High Temperature Measurements in Microwave-Assisted Catalytic Reactors

PubMed Central

2017-01-01

The complexity and challenges in noncontact temperature measurements inside microwave-heated catalytic reactors are presented in this paper. A custom-designed microwave cavity has been used to focus the microwave field on the catalyst and enable monitoring of the temperature field in 2D. A methodology to study the temperature distribution in the catalytic bed by using a thermal camera in combination with a thermocouple for a heterogeneous catalytic reaction (methane dry reforming) under microwave heating has been demonstrated. The effects of various variables that affect the accuracy of temperature recordings are discussed in detail. The necessity of having at least one contact sensor, such as a thermocouple, or some other microwave transparent sensor, is recommended to keep track of the temperature changes occurring in the catalytic bed during the reaction under microwave heating. PMID:29170599

Cyclic process for producing methane from carbon monoxide with heat removal

DOEpatents

Frost, Albert C.; Yang, Chang-lee

1982-01-01

Carbon monoxide-containing gas streams are converted to methane by a cyclic, essentially two-step process in which said carbon monoxide is disproportionated to form carbon dioxide and active surface carbon deposited on the surface of a catalyst, and said carbon is reacted with steam to form product methane and by-product carbon dioxide. The exothermic heat of reaction generated in each step is effectively removed during each complete cycle so as to avoid a build up of heat from cycle-to-cycle, with particularly advantageous techniques being employed for fixed bed, tubular and fluidized bed reactor operations.

Catalytic wet air oxidation of aniline with nanocasted Mn-Ce-oxide catalyst.

PubMed

Levi, R; Milman, M; Landau, M V; Brenner, A; Herskowitz, M

2008-07-15

The catalytic wet air oxidation of aqueous solution containing 1000 ppm aniline was conducted in a trickle-bed reactor packed with a novel nanocasted Mn-Ce-oxide catalyst (surface area of 300 m2/g) prepared using SBA-15 silica as a hard template. A range of liquid hourly space velocities (5-20 h(-1)) and temperatures (110-140 degrees C) at 10 bar of oxygen were tested. The experiments were conducted to provide the intrinsic performance of the catalysts. Complete aniline conversion, 90% TOC conversion, and 80% nitrogen mineralization were achieved at 140 degrees C and 5 h(-1). Blank experiments yielded relatively low homogeneous aniline (<35%) and negligible TOC conversions. Fast deactivation of the catalysts was experienced due to leaching caused by complexation with aniline. Acidification of the solution with HCI (molar HCI to aniline ratio of 1.2) was necessary to avoid colloidization and leaching of the nanoparticulate catalyst components. The catalyst displayed stable performance for over 200 h on stream.

Selective Hydrodeoxygenation of 5-Hydroxymethylfurfural to 2,5-Dimethylfuran over Heterogeneous Iron Catalysts.

PubMed

Li, Jiang; Liu, Jun-Ling; Liu, He-Yang; Xu, Guang-Yue; Zhang, Jun-Jie; Liu, Jia-Xing; Zhou, Guang-Lin; Li, Qin; Xu, Zhi-Hao; Fu, Yao

2017-04-10

This work provided the first example of selective hydrodeoxygenation of 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF) over heterogeneous Fe catalysts. A catalyst prepared by the pyrolysis of an Fe-phenanthroline complex on activated carbon at 800 °C was demonstrated to be the most active heterogeneous Fe catalyst. Under the optimal reaction conditions, complete conversion of HMF was achieved with 86.2 % selectivity to DMF. The reaction pathway was investigated thoroughly, and the hydrogenation of the C=O bond in HMF was demonstrated to be the rate-determining step during the hydrodeoxygenation, which could be accelerated greatly by using alcohol solvents as additional H-donors. The excellent stability of the Fe catalyst, which was probably a result of the well-preserved active species and the pore structure of the Fe catalyst in the presence of H 2 , was demonstrated in batch and continuous flow fixed-bed reactors. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrodesulfurization reactions of atmospheric gas oil over CoMo/alumina-aluminum borate catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiuping Li; Jungchung Wu; Yuwen Chen

1993-08-01

A precipitation technique at constant pH value was used to prepare a series of alumina-aluminum borates (AABs) with various Al/B atomic ratios. These materials were used as the supports of Co-Mo catalysts. Hydrodesulfurization (HDS) of Kuwait atmospheric gas (AGO) oil was carried out over these presulfided catalysts in a bench-scale trickle bed reactor at 400 psi and 340 C. All CoMo/AAB catalysts are much more active than the conventional CoMo/Al[sub 2]O[sub 3] catalyst on HDS reactions. A correlation exists between the acidity and the HDS activity of the catalysts. The high activities of the CoMo/AAB catalysts can be rationalized onmore » the presence of boron. On one hand, it can increase the metal dispersions and hydrogenation capabilities. On the other hand, it can enhance the acidities and cracking abilities of the catalysts. The desulfurization data can be fitted with a pseudo-second-order rate equation. The activation energy for desulfurization is found to be 26 kcal/mol.« less

Catalytic wet oxidation: mathematical modeling of multicompound destruction.

PubMed

Yang, J; Hand, D W; Hokanson, D R; Crittenden, J C; Oman, E J

2003-01-01

A mathematical model of a three-phase catalytic reactor, CatReac, was developed for analysis and optimization of a catalytic oxidation reactor that is used in the International Space Station potable water processor. The packed-bed catalytic reactor, known as the volatile reactor assembly (VRA), is operated as a three-phase reactor and contains a proprietary catalyst, a pure-oxygen gas phase, and the contaminated water. The contaminated water being fed to the VRA primarily consists of acetic acid, acetone, ethanol, 1-propanol, 2-propanol, and propionic acid ranging in concentration from 1 to 10 mg/L. The Langmuir-Hinshelwood Hougen-Watson (L-H) (Hougen, 1943) expression was used to describe the surface reaction rate for these compounds. Single and multicompound short-column experiments were used to determine the L-H rate parameters and calibrate the model. The model was able to predict steady-state multicomponent effluent profiles for short and full-scale reactor experiments.

ATTRITION RESISTANT IRON-BASED FISCHER-TROPSCH CATALYSTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

JAMES G. GOODWIN, JR.; JAMES J. SPIVEY; K. JOTHIMURUGESAN

1998-09-17

The Fischer-Tropsch (F-T) reaction provides a way of converting coal-derived synthesis gas (CO+H{sub 2}) to liquid fuels. Since the reaction is highly exothermic, one of the major problems in control of the reaction is heat removal. Recent work has shown that the use of slurry bubble column reactors (SBCRs) can largely solve this problem. Iron-based (Fe) catalysts are preferred catalysts for F-T when using low CO/H{sub 2} ratio synthesis gases derived from modern coal gasifiers. This is because in addition to reasonable F-T activity, the F-T catalysts also possess high water gas shift (WGS) activity. However, a serious problem withmore » the use of Fe catalysts in a SBCR is their tendency to undergo attrition. This can cause fouling/plugging of downstream filters and equipment, making the separation of catalyst from the oil/wax product very difficult if not impossible, and results in a steady loss of catalyst from the reactor. The objectives of this research are to develop a better understanding of the parameters affecting attrition resistance of Fe F-T catalysts suitable for use in SBCRs and to incorporate this understanding into the design of novel Fe catalysts having superior attrition resistance. Catalyst preparations will be based on the use of spray drying and will be scalable using commercially available equipment. The research will employ among other measurements, attrition testing and F-T synthesis, including long duration slurry reactor runs in order to ascertain the degree of success of the various preparations. The goal is to develop an Fe catalyst which can be used in a SBCR having only an internal filter for separation of the catalyst from the liquid product, without sacrificing F-T activity and selectivity. The effect of silica addition via coprecipitation and as a binder to a doubly promoted Fischer-Tropsch synthesis iron catalyst (100 Fe/5 Cu/4.2 K) was studied. The catalysts were prepared by coprecipitation, followed by binder addition and drying in a 1 m diameter, 2 m tall spray dryer. The binder silica content was varied from 0 to 20 wt %. A catalyst with 12 wt % binder silica was found to have the highest attrition resistance. F-T reaction studies over 100 hours in a fixed-bed reactor showed that this catalyst maintained around 95 % CO conversion with a methane selectivity of less than 7 wt % and a C{sub 5}{sup +} selectivity of greater than 73 wt %. The effect of adding precipitated silica from 0 to 20 parts by weight to this catalyst (containing 12 wt % binder silica) was also studied. Addition of precipitated silica was found to be detrimental to attrition resistance and resulted in increased methane and reduced wax formation.« less

TiO2-photocatalyzed As(III) oxidation in a fixed-bed, flow-through reactor.

PubMed

Ferguson, Megan A; Hering, Janet G

2006-07-01

Compliance with the U.S. drinking water standard for arsenic (As) of 10 microg L(-1) is required in January 2006. This will necessitate implementation of treatment technologies for As removal by thousands of water suppliers. Although a variety of such technologies is available, most require preoxidation of As(III) to As(V) for efficient performance. Previous batch studies with illuminated TiO2 slurries have demonstrated that TiO2-photocatalyzed AS(III) oxidation occurs rapidly. This study examined reaction efficiency in a flow-through, fixed-bed reactor that provides a better model for treatment in practice. Glass beads were coated with mixed P25/sol gel TiO2 and employed in an upflow reactor irradiated from above. The reactor residence time, influent As(III) concentration, number of TiO2 coatings on the beads, solution matrix, and light source were varied to characterize this reaction and determine its feasibility for water treatment. Repeated usage of the same beads in multiple experiments or extended use was found to affect effluent As(V) concentrations but not the steady-state effluent As(III) concentration, which suggests that As(III) oxidation at the TiO2 surface undergoes dynamic sorption equilibration. Catalyst poisoning was not observed either from As(V) or from competitively adsorbing anions, although the higher steady-state effluent As(III) concentrations in synthetic groundwater compared to 5 mM NaNO3 indicated that competitive sorbates in the matrix partially hinder the reaction. A reactive transport model with rate constants proportional to incident light at each bead layer fit the experimental data well despite simplifying assumptions. TiO2-photocatalyzed oxidation of As(III) was also effective under natural sunlight. Limitations to the efficiency of As(III) oxidation in the fixed-bed reactor were attributable to constraints of the reactor geometry, which could be overcome by improved design. The fixed-bed TiO2 reactor offers an environmentally benign method for As(III) oxidation.

Thermal Catalytic Oxidation of Airborne Contaminants by a Reactor Using Ultra-Short Channel Length, Monolithic Catalyst Substrates

NASA Technical Reports Server (NTRS)

Perry, J. L.; Tomes, K. M.; Tatara, J. D.

2005-01-01

Contaminated air, whether in a crewed spacecraft cabin or terrestrial work and living spaces, is a pervasive problem affecting human health, performance, and well being. The need for highly effective, economical air quality processes spans a wide range of terrestrial and space flight applications. Typically, air quality control processes rely on absorption-based processes. Most industrial packed-bed adsorption processes use activated carbon. Once saturated, the carbon is either dumped or regenerated. In either case, the dumped carbon and concentrated waste streams constitute a hazardous waste that must be handled safely while minimizing environmental impact. Thermal catalytic oxidation processes designed to address waste handling issues are moving to the forefront of cleaner air quality control and process gas decontamination processes. Careful consideration in designing the catalyst substrate and reactor can lead to more complete contaminant destruction and poisoning resistance. Maintenance improvements leading to reduced waste handling and process downtime can also be realized. Performance of a prototype thermal catalytic reaction based on ultra-short waste channel, monolith catalyst substrate design, under a variety of process flow and contaminant loading conditions, is discussed.

Aromatic chemicals by iron-catalyzed hydrotreatment of lignin pyrolysis vapor.

PubMed

Olcese, Roberto Nicolas; Lardier, George; Bettahar, Mohammed; Ghanbaja, Jaafar; Fontana, Sébastien; Carré, Vincent; Aubriet, Frédéric; Petitjean, Dominique; Dufour, Anthony

2013-08-01

Lignin is a potential renewable material for the production of bio-sourced aromatic chemicals. We present the first hydrotreatment of lignin pyrolysis vapors, before any condensation, using inexpensive and sustainable iron-silica (Fe/SiO2 ) and iron-activated carbon (Fe/AC) catalysts. Lignin pyrolysis was conducted in a tubular reactor and vapors were injected in a fixed bed of catalysts (673 K, 1 bar) with stacks to investigate the profile of coke deposit. More than 170 GC-analyzable compounds were identified by GCxGC (heart cutting)/flame ionization detector mass spectrometry. Lignin oligomers were analyzed by very high resolution mass spectrometry, called the "petroleomic" method. They are trapped by the catalytic fixed bed and, in particular, by the AC. The catalysts showed a good selectivity for the hydrodeoxygenation of real lignin vapors to benzene, toluene, xylenes, phenol, cresols, and alkyl phenols. The spent catalysts were characterized by temperature-programmed oxidation, transmission electron microscopy (TEM), and N2 sorption. Micropores in the Fe/AC catalyst are completely plugged by coke deposits, whereas the mesoporous structure of Fe/SiO2 is unaffected. TEM images reveal two different types of coke deposit: 1) catalytic coke deposited in the vicinity of iron particles and 2) thermal coke (carbonaceous particles ≈1 μm in diameter) formed from the gas-phase growth of lignin oligomers. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Low-temperature upgrading of low-calorific biogas for CO2 mitigation using DBD-catalyst hybrid reactor

NASA Astrophysics Data System (ADS)

Nozaki, Tomohiro; Tsukijihara, Hiroyuki; Fukui, Wataru; Okazaki, Ken

2006-10-01

Although huge amounts of biogas, which consists of 20-60% of CH4 in CO2/N2, can be obtained from landfills, coal mines, and agricultural residues, most of them are simply flared and wasted: because global warming potential of biogas is 5-15 times as potent as CO2. Poor combustibility of such biogas makes it difficult to utilize in conventional energy system. The purpose of this project is to promote the profitable recovery of methane from poor biogas via non-thermal plasma technology. We propose low-temperature steam reforming of biogas using DBD generated in catalyst beds. Methane is partially converted into hydrogen, and then fed into internal combustion engines for improved ignition stability as well as efficient operation. Low-temperature steam reforming is beneficial because exhaust gas from an engine can be used to activate catalyst beds. Space velocity (3600-15000 hr-1), reaction temperature (300-650^oC), and energy cost (30-150 kJ per mol CH4) have been investigated with simulated biogas (20-60% CH4 in mixtures of CO2/N2). The DBD enhances reaction rate of CH4 by a factor of ten at given catalyst temperatures, which is a rate-determining step of methane steam reforming, while species concentration of upgraded biogas was governed by thermodynamic equilibrium in the presence of catalyst.

Flowthrough Reductive Catalytic Fractionation of Biomass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, Eric M.; Stone, Michael L.; Katahira, Rui

2017-11-01

Reductive catalytic fractionation (RCF) has emerged as a leading biomass fractionation and lignin valorization strategy. Here, flowthrough reactors were used to investigate RCF of poplar. Most RCF studies to date have been conducted in batch, but a flow-based process enables the acquisition of intrinsic kinetic and mechanistic data essential to accelerate the design, optimization, and scale-up of RCF processes. Time-resolved product distributions and yields obtained from experiments with different catalyst loadings were used to identify and deconvolute events during solvolysis and hydrogenolysis. Multi-bed RCF experiments provided unique insights into catalyst deactivation, showing that leaching, sintering, and surface poisoning are causesmore » for decreased catalyst performance. The onset of catalyst deactivation resulted in higher concentrations of unsaturated lignin intermediates and increased occurrence of repolymerization reactions, producing high-molecular-weight species. Overall, this study demonstrates the concept of flowthrough RCF, which will be vital for realistic scale-up of this promising approach.« less

Fischer-Tropsch Cobalt Catalyst Activation and Handling Through Wax Enclosure Methods

NASA Technical Reports Server (NTRS)

Klettlinger, Jennifer L. S.; Yen, Chia H.; Nakley, Leah M.; Surgenor, Angela D.

2016-01-01

Fischer-Tropsch (F-T) synthesis is considered a gas to liquid process which converts syn-gas, a gaseous mixture of hydrogen and carbon monoxide, into liquids of various hydrocarbon chain length and product distributions. Cobalt based catalysts are used in F-T synthesis and are the focus of this paper. One key concern with handling cobalt based catalysts is that the active form of catalyst is in a reduced state, metallic cobalt, which oxidizes readily in air. In laboratory experiments, the precursor cobalt oxide catalyst is activated in a fixed bed at 350 ?C then transferred into a continuous stirred tank reactor (CSTR) with inert gas. NASA has developed a process which involves the enclosure of active cobalt catalyst in a wax mold to prevent oxidation during storage and handling. This improved method allows for precise catalyst loading and delivery into a CSTR. Preliminary results indicate similar activity levels in the F-T reaction in comparison to the direct injection method. The work in this paper was supported by the NASA Fundamental Aeronautics Subsonics Fixed Wing Project.

BNNT Growth in a Fluidized Bed Reactor

DTIC Science & Technology

2016-06-24

kinetics. Figure 1. Catalyst Screen System and 23 Factorial Design Matrix Figures 2 and 3, below, contain photographs of unheated and heated...boron that appear as black spots in each photograph . No fusion of individual lithium diborate particles is observed. Figure 4 is a photograph of a...developed at NASA [2]. Through a fortunate meeting with a former colleague at the National Institute of Aerospace (NIA), we discovered that

Small-Scale Coal-Biomass to Liquids Production Using Highly Selective Fischer-Tropsch Synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gangwal, Santosh K.; McCabe, Kevin

2015-04-30

The research project advanced coal-to-liquids (CTL) and coal-biomass to liquids (CBTL) processes by testing and validating Chevron’s highly selective and active cobalt-zeolite hybrid Fischer-Tropsch (FT) catalyst to convert gasifier syngas predominantly to gasoline, jet fuel and diesel range hydrocarbon liquids, thereby eliminating expensive wax upgrading operations The National Carbon Capture Center (NCCC) operated by Southern Company (SC) at Wilsonville, Alabama served as the host site for the gasifier slip-stream testing/demonstration. Southern Research designed, installed and commissioned a bench scale skid mounted FT reactor system (SR-CBTL test rig) that was fully integrated with a slip stream from SC/NCCC’s transport integrated gasifiermore » (TRIG TM). The test-rig was designed to receive up to 5 lb/h raw syngas augmented with bottled syngas to adjust the H 2/CO molar ratio to 2, clean it to cobalt FT catalyst specifications, and produce liquid FT products at the design capacity of 2 to 4 L/day. It employed a 2-inch diameter boiling water jacketed fixed-bed heat-exchange FT reactor incorporating Chevron’s catalyst in Intramicron’s high thermal conductivity micro-fibrous entrapped catalyst (MFEC) packing to efficiently remove heat produced by the highly exothermic FT reaction.« less

Simulation for Supporting Scale-Up of a Fluidized Bed Reactor for Advanced Water Oxidation

PubMed Central

Abdul Raman, Abdul Aziz; Daud, Wan Mohd Ashri Wan

2014-01-01

Simulation of fluidized bed reactor (FBR) was accomplished for treating wastewater using Fenton reaction, which is an advanced oxidation process (AOP). The simulation was performed to determine characteristics of FBR performance, concentration profile of the contaminants, and various prominent hydrodynamic properties (e.g., Reynolds number, velocity, and pressure) in the reactor. Simulation was implemented for 2.8 L working volume using hydrodynamic correlations, continuous equation, and simplified kinetic information for phenols degradation as a model. The simulation shows that, by using Fe3+ and Fe2+ mixtures as catalyst, TOC degradation up to 45% was achieved for contaminant range of 40–90 mg/L within 60 min. The concentration profiles and hydrodynamic characteristics were also generated. A subsequent scale-up study was also conducted using similitude method. The analysis shows that up to 10 L working volume, the models developed are applicable. The study proves that, using appropriate modeling and simulation, data can be predicted for designing and operating FBR for wastewater treatment. PMID:25309949

Improvement of yields and rates during enzymatic hydrolysis of cellulose to glucose. Progress report, March 1, 1979-May 31, 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sundstrom, D W; Klei, H E; Coughlin, R W

1979-05-01

The objective of this program is to show that the conversion of cellulose to glucose can be significantly increased by enzymatically removing the inhibitory cellobiose from the reaction system using immobilized ..beta..-glucosidase (..beta..-G). An enzymatic catalyst was prepared and used in a fluidized bed with cellobiose as the substrate, only a 10% loss of activity was observed during a 500 hour period. Cellulose was hydrolyzed in two batch reactors operated side-by-side, with one reactor containing immobilized ..beta..-G and cellulose and the other reactor containing an equal amount of cellulose only. After 30 hours the reactor containing the immobilized ..beta..-G hadmore » 100% more glucose, indicating that the catalytic removal of the cellobiose had a significant effect upon the production of glucose.« less

Reactor for exothermic reactions

DOEpatents

Smith, Jr., Lawrence A.; Hearn, Dennis; Jones, Jr., Edward M.

1993-01-01

A liquid phase process for oligomerization of C.sub.4 and C.sub.5 isoolefins or the etherification thereof with C.sub.1 to C.sub.6 alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120.degree. to 300.degree. F. Wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

Reactor for exothermic reactions

DOEpatents

Smith, L.A. Jr.; Hearn, D.; Jones, E.M. Jr.

1993-03-02

A liquid phase process is described for oligomerization of C[sub 4] and C[sub 5] isoolefins or the etherification thereof with C[sub 1] to C[sub 6] alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300 F. Wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

CO{sub 2} Reuse in Petrochemical Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jason Trembly; Brian Turk; Maruthi Pavani

2010-12-31

To address public concerns regarding the consequences of climate change from anthropogenic carbon dioxide (CO{sub 2}) emissions, the U.S. Department of Energy's National Energy Technology Laboratory (DOE/NETL) is actively funding a CO{sub 2} management program to develop technologies capable of mitigating CO{sub 2} emissions from power plant and industrial facilities. Over the past decade, this program has focused on reducing the costs of carbon capture and storage technologies. Recently, DOE/NETL launched an alternative CO{sub 2} mitigation program focused on beneficial CO{sub 2} reuse to support the development of technologies that mitigate emissions by converting CO{sub 2} into valuable chemicals andmore » fuels. RTI, with DOE/NETL support, has been developing an innovative beneficial CO{sub 2} reuse process for converting CO{sub 2} into substitute natural gas (SNG) by using by-product hydrogen (H{sub 2)-containing fuel gas from petrochemical facilities. This process leveraged commercial reactor technology currently used in fluid catalytic crackers in petroleum refining and a novel nickel (Ni)-based catalyst developed by RTI. The goal was to generate an SNG product that meets the pipeline specifications for natural gas, making the SNG product completely compatible with the existing natural gas infrastructure. RTI's technology development efforts focused on demonstrating the technical feasibility of this novel CO{sub 2} reuse process and obtaining the necessary engineering information to design a pilot demonstration unit for converting about 4 tons per day (tons/day) of CO{sub 2} into SNG at a suitable host site. This final report describes the results of the Phase I catalyst and process development efforts. The methanation activity of several commercial fixed-bed catalysts was evaluated under fluidized-bed conditions in a bench-scale reactor to identify catalyst performance targets. RTI developed two fluidizable Ni-based catalyst formulations (Cat-1 and Cat-3) that demonstrated equal or better performance than that of commercial methanation catalysts. The Cat-1 and Cat-3 formulations were successfully scaled up using commercial manufacturing equipment at the Sud-Chemie Inc. pilot-plant facility in Louisville, KY. Pilot transport reactor testing with RTI's Cat-1 formulation at Kellog Brown & Root's Technology Center demonstrated the ability of the process to achieve high single-pass CO{sub 2} conversion. Using information acquired from bench- and pilot-scale testing, a basic engineering design package was prepared for a 4-ton/day CO{sub 2} pilot demonstration unit, including process and instrumentation diagrams, equipment list, control philosophy, and preliminary cost estimate.« less

Nannochloropsis algae pyrolysis with ceria-based catalysts for production of high-quality bio-oils.

PubMed

Aysu, Tevfik; Sanna, Aimaro

2015-10-01

Pyrolysis of Nannochloropsis was carried out in a fixed-bed reactor with newly prepared ceria based catalysts. The effects of pyrolysis parameters such as temperature and catalysts on product yields were investigated. The amount of bio-char, bio-oil and gas products, as well as the compositions of the resulting bio-oils was determined. The results showed that both temperature and catalyst had significant effects on conversion of Nannochloropsis into solid, liquid and gas products. The highest bio-oil yield (23.28 wt%) and deoxygenation effect was obtained in the presence of Ni-Ce/Al2O3 as catalyst at 500°C. Ni-Ce/Al2O3 was able to retain 59% of the alga starting energy in the bio-oil, compared to only 41% in absence of catalyst. Lower content of acids and oxygen in the bio-oil, higher aliphatics (62%), combined with HHV show promise for production of high-quality bio-oil from Nannochloropsis via Ni-Ce/Al2O3 catalytic pyrolysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

hcp-Co nanowires grown on metallic foams as catalysts for the Fischer-Tropsch synthesis.

PubMed

Soulantica, Katerina; Harmel, Justine; Peres, Laurent; Estrader, Marta; Berliet, Adrien; Maury, Sylvie; Fécant, Antoine; Chaudret, Bruno; Serp, Philippe

2018-06-12

The possibility to control the structural characteristics of the active phase of supported catalysts offers the opportunity to improve catalyst performance, especially in structure sensitive catalytic reactions. In parallel, heat management is of critical importance for the catalytic performance in highly endo- or exothermic reactions. The Fisher-Tropsch synthesis (FTS) is a structure sensitive exothermic reaction, which enables catalytic transformation of syngas to high quality liquid fuels. We have elaborated monolithic cobalt based heterogeneous catalysts through a wet chemistry approach that allows control over nanocrystal shape and crystallographic phase, while at the same time enables heat management. Copper and nickel foams have been employed as supports for the epitaxial growth of hcp-Co nanowires, directly from a solution containing a coordination compound of cobalt and stabilizing ligands. The Co/Cufoam catalyst has been tested for the Fischer-Tropsch synthesis in fixed bed reactor, showing stability, and significantly superior activity and selectivity towards C5+ compared to a Co/SiO2-Al2O3 reference catalyst under the same conditions. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrogen production from biomass gasification using biochar as a catalyst/support.

PubMed

Yao, Dingding; Hu, Qiang; Wang, Daqian; Yang, Haiping; Wu, Chunfei; Wang, Xianhua; Chen, Hanping

2016-09-01

Biochar is a promising catalyst/support for biomass gasification. Hydrogen production from biomass steam gasification with biochar or Ni-based biochar has been investigated using a two stage fixed bed reactor. Commercial activated carbon was also studied as a comparison. Catalyst was prepared with an impregnation method and characterized by X-ray diffraction, specific surface and porosity analysis, X-ray fluorescence and scanning electron micrograph. The effects of gasification temperature, steam to biomass ratio, Ni loading and bio-char properties on catalyst activity in terms of hydrogen production were explored. The Ni/AC catalyst showed the best performance at gasification temperature of 800°C, S/B=4, Ni loading of 15wt.%. Texture and composition characterization of the catalysts suggested the interaction between volatiles and biochar promoted the reforming of pyrolysis volatiles. Cotton-char supported Ni exhibited the highest activity of H2 production (64.02vol.%, 92.08mgg(-1) biomass) from biomass gasification, while rice-char showed the lowest H2 production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study on the pyrolysis of cellulose for bio-oil with mesoporous molecular sieve catalysts.

PubMed

Yu, Feng-wen; Ji, Deng-xiang; Nie, Yong; Luo, Yao; Huang, Cheng-jie; Ji, Jian-bing

2012-09-01

Mesoporous materials possess a hexagonal array of uniform mesopores, high surface areas, and moderate acidity. They are one of the important catalysts in the field of catalytic pyrolysis. In this paper, mesoporous materials of Al-MCM-41, La-Al-MCM-41, and Ce-Al-MCM-41 were synthesized, characterized, and tested as catalysts in the cellulose catalytic pyrolysis process using a fixed bed pyrolysis reactor. The results showed that mesoporous materials exhibited a strong influence on the pyrolytic behavior of cellulose. The presence of these mesoporous molecular sieve catalysts could vary the yield of products, which was that they could decrease the yield of liquid and char and increase the yield of gas product, and could promote high-carbon chain compounds to break into low-carbon chain compounds. Mesoporous molecular sieve catalysts were benefit to the reaction of dehydrogenation and deoxidation and the breakdown of carbon chain. Further, La-Al-MCM-41 and Ce-Al-MCM-41 catalysts can produce more toluene and 2-methoxy-phenol, as compared to the non-catalytic runs.

Zircon Supported Copper Catalysts for the Steam Reforming of Methanol

NASA Astrophysics Data System (ADS)

Widiastri, M.; Fendy, Marsih, I. N.

2008-03-01

Steam reforming of methanol (SRM) is known as one of the most favorable catalytic processes for producing hydrogen. Current research on zirconia, ZrO2 supported copper catalyst revealed that CuO/ZrO2 as an active catalyst for the SRM. Zircon, ZrSiO4 is available from the by-product of tin mining. In the work presented here, the catalytic properties of CuO/ZrSiO4 with various copper oxide compositions ranging from 2.70% (catalyst I), 4.12% (catalyst II), and 7.12%-mass (catalyst III), synthesized by an incipient wetness impregnation technique, were investigated to methanol conversion, selectivity towards CO formation, and effect of ZnO addition (7.83%CuO/8.01%ZnO/ZrSiO4 = catalyst V). The catalytic activity was obtained using a fixed bed reactor and the zircon supported catalyst activity was compared to those of CuO/ZnO/Al2O3 catalyst (catalyst IV) and commercial Kujang LTSC catalyst. An X-ray powder diffraction (XRD) analysis was done to identify the abundant phases of the catalysts. The catalysts topography and particle diameter were measured with scanning electron microscopy (SEM) and composition of the catalysts was measured by SEM-EDX, scanning electron microscope-energy dispersive using X-ray analysis. The results of this research provide information on the possibility of using zircon (ZrSiO4) as solid support for SRM catalysts.

40 CFR 63.4363 - How do I establish the add-on control device operating limits during the performance test?

Code of Federal Regulations, 2010 CFR

2010-07-01

... performance test, you must monitor and record the temperature at the inlet to the catalyst bed and the temperature difference across the catalyst bed at least once every 15 minutes during each of the three test... temperature at the inlet to the catalyst bed and the average temperature difference across the catalyst bed...

Isomerization of n-hexane and n-pentane mixture on Pt-alumina catalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radhi, M.A.; Al-Mutawalli, F.S.; Al-Sammarie, E.A.

A mixture of n-hexane and n-penane (1:1) by volume was isomerized on commercial Pt-alumina catalyst in a continuously fixed-bed reactor at atmospheric pressure. The effect of temperature, LHSV, hydrogen/hyrocarbon molar ratio and chlorine concentration were studied. It was found that the yield of isohexanes and isopentane increases with increasing the chloride added up to 0.1 and 0.2 mole % CCl/sub 4/ respectively. The rate of isomerization became slower at higher concentrations. Isomerization activity of the catalyst increases with increasing temperature ranging between 350-400/sup 0/C. The yield of isomers decrease with increasing temperature above 400/sup 0/C. The relative conversion of n-hexanemore » in the mixture was found to be more than the conversion of pure n-hexane at the same conditions.« less

Hydrogen Production by Sorption Enhanced Steam Reforming (SESR) of Biomass in a Fluidised-Bed Reactor Using Combined Multifunctional Particles

PubMed Central

Zheng, Liya; Zhang, Zili; Fennell, Paul S.

2018-01-01

The performance of combined CO2-sorbent/catalyst particles for sorption enhanced steam reforming (SESR), prepared via a simple mechanical mixing protocol, was studied using a spout-fluidised bed reactor capable of continuous solid fuel (biomass) feeding. The influence of particle size (300–500 and 710–1000 µm), CaO loading (60–100 wt %), Ni-loading (10–40 wt %) and presence of dicalcium silicate support (22.6 wt %) on SESR process performance were investigated. The combined particles were characterised by their density, porosity and CO2 carrying capacity with the analysis by thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH) and mercury intrusion porosimetry (MIP). All experiments were conducted with continuous oak biomass feeding at a rate of 0.9 g/min ± 10%, and the reactor was operated at 660 ± 5 °C, 1 atm and 20 ± 2 vol % steam which corresponds to a steam-to-carbon ratio of 1.2:1. Unsupported combined particles containing 21.0 wt % Ni and 79 wt % CaO were the best performing sorbent/catalyst particle screened in this study, when accounting for the cost of Ni and the improvement in H2 produced by high Ni content particles. SESR tests with these combined particles produced 61 mmol H2/gbiomass (122 g H2/kgbiomass) at a purity of 61 vol %. Significant coke formation within the feeding tube and on the surfaces of the particles was observed which was attributed to the low steam to carbon ratio utilised. PMID:29883427

ATTRITION RESISTANT IRON-BASED FISCHER-TROPSCH CATALYSTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

James G. Goodwin, Jr.; James J. Spivey; K. Jothimurugesan

1999-03-29

The Fischer-Tropsch (F-T) reaction provides a way of converting coal-derived synthesis gas (CO+H{sub 2}) to liquid fuels. Since the reaction is highly exothermic, one of the major problems in control of the reaction is heat removal. Recent work has shown that the use of slurry bubble column reactors (SBCRs) can largely solve this problem. Iron-based (Fe) catalysts are preferred catalysts for F-T when using low CO/H2 ratio synthesis gases derived from modern coal gasifiers. This is because in addition to reasonable F-T activity, the F-T catalysts also possess high water gas shift (WGS) activity. However, a serious problem with themore » use of Fe catalysts in a SBCR is their tendency to undergo attrition. This can cause fouling/plugging of downstream filters and equipment, making the separation of catalyst from the oil/wax product very difficult if not impossible, and results in a steady loss of catalyst from the reactor. The objectives of this research are to develop a better understanding of the parameters affecting attrition resistance of Fe F-T catalysts suitable for use in SBCRs and to incorporate this understanding into the design of novel Fe catalysts having superior attrition resistance. Catalyst preparations will be based on the use of spray drying and will be scalable using commercially available equipment. The research will employ among other measurements, attrition testing and F-T synthesis, including long duration slurry reactor runs in order to ascertain the degree of success of the various preparations. The goal is to develop an Fe catalyst which can be used in a SBCR having only an internal filter for separation of the catalyst from the liquid product, without sacrificing F-T activity and selectivity. The effect of silica addition via coprecipitation and as a binder to a doubly promoted Fischer-Tropsch synthesis iron catalyst (100 Fe/5 Cu/4.2 K) was studied. The catalysts were prepared by coprecipitation, followed by binder addition and drying in a 1 m diameter, 2 m tall spray dryer. The binder silica content was varied from 0 to 20 wt %. A catalyst with 12 wt % binder silica was found to have the highest attrition resistance. F-T reaction studies over 100 hours in a fixed-bed reactor showed that this catalyst maintained around 95 % CO conversion with a methane selectivity of less than 7 wt % and a C5 + selectivity of greater than 73 wt %. The effect of adding precipitated silica from 0 to 20 parts by weight to this catalyst (containing 12 wt % binder silica) was also studied. Addition of precipitated silica was found to be detrimental to attrition resistance and resulted in increased methane and reduced wax formation. An HPR series of proprietary catalysts was prepared to further improve the attrition resistance. Based on the experience gained, a proprietary HPR-43 catalyst has been successfully spray dried in 500 g quantity. This catalyst showed 95 % CO conversion over 125 h and had less than 4 % methane selectivity. Its attrition resistance was one of the highest among the catalyst tested.« less

Novel Fast Pyrolysis/Catalytic Technology for the Production of Stable Upgraded Liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oyama, Ted; Agblevor, Foster; Battaglia, Francine

The objective of the proposed research is the demonstration and development of a novel biomass pyrolysis technology for the production of a stable bio-oil. The approach is to carry out catalytic hydrodeoxygenation (HDO) and upgrading together with pyrolysis in a single fluidized bed reactor with a unique two-level design that permits the physical separation of the two processes. The hydrogen required for the HDO will be generated in the catalytic section by the water-gas shift reaction employing recycled CO produced from the pyrolysis reaction itself. Thus, the use of a reactive recycle stream is another innovation in this technology. Themore » catalysts will be designed in collaboration with BASF Catalysts LLC (formerly Engelhard Corporation), a leader in the manufacture of attrition-resistant cracking catalysts. The proposed work will include reactor modeling with state-of-the-art computational fluid dynamics in a supercomputer, and advanced kinetic analysis for optimization of bio-oil production. The stability of the bio-oil will be determined by viscosity, oxygen content, and acidity determinations in real and accelerated measurements. A multi-faceted team has been assembled to handle laboratory demonstration studies and computational analysis for optimization and scaleup.« less

Production and optimization of biodiesel using mixed immobilized biocatalysts in packed bed reactor.

PubMed

Bakkiyaraj, S; Syed, Mahin Basha; Devanesan, M G; Thangavelu, Viruthagiri

2016-05-01

Vegetable oils are used as raw materials for biodiesel production using transesterification reaction. Several methods for the production of biodiesel were developed using chemical (alkali and acidic compounds) and biological catalysts (lipases). Biodiesel production catalyzed by lipases is energy and cost-saving processes and is carried out at normal temperature and pressure. The need for an efficient method for screening larger number of variables has led to the adoption of statistical experimental design. In the present study, packed bed reactor was designed to study with mixed immobilized biocatalysts to have higher productivity under optimum conditions. Contrary to the single-step acyl migration mechanism, a two-step stepwise reaction mechanism involving immobilized Candida rugosa lipase and immobilized Rhizopus oryzae cells was employed for the present work. This method was chosen because enzymatic hydrolysis followed by esterification can tolerate high free fatty acid containing oils. The effects of flow rate and bed height on biodiesel yield were studied using two factors five-level central composite design (CCD) and response surface methodology (RSM). Maximum biodiesel yield of 85 and 81 % was obtained for jatropha oil and karanja oil with the optimum bed height and optimum flow rate of 32.6 cm and 1.35 L/h, and 32.6 cm and 1.36 L/h, respectively.

Etherification process

DOEpatents

Smith, Jr., Lawrence A.; Hearn, Dennis; Jones, Jr., Edward M.

1990-01-01

A liquid phase process for oligomerization of C.sub.4 and C.sub.5 isoolefins or the etherification thereof with C.sub.1 to C.sub.6 alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120.degree. to 300.degree. F. wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

Oligomerization process

DOEpatents

Smith, Jr., Lawrence A.; hearn, Dennis; Jones, Jr., Edward M.

1991-01-01

A liquid phase process for oligomerization of C.sub.4 and C.sub.5 isoolefins or the etherification thereof with C.sub.1 to C.sub.6 alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300.degree. F. wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

Hydrocarbon liquid production via the bioCRACK process and catalytic hydroprocessing of the product oil

DOE PAGES

Schwaiger, Nickolaus; Elliott, Douglas C.; Ritzberger, Jurgen; ...

2015-01-01

Continuous hydroprocessing of liquid phase pyrolysis bio-oil, provided by BDI-BioEnergy International bioCRACK pilot plant at OMV Refinery in Schwechat/Vienna Austria was investigated. These hydroprocessing tests showed promising results using catalytic hydroprocessing strategies developed for unfractionated bio-oil. A sulfided base metal catalyst (CoMo on Al2O3) was evaluated. The bed of catalyst was operated at 400 °C in a continuous-flow reactor at a pressure of 12.1 MPa with flowing hydrogen. The condensed liquid products were analyzed and found that the hydrocarbon liquid was significantly hydrotreated so that nitrogen and sulfur were below the level of detection (<0.05), while the residual oxygen rangedmore » from 0.7 to 1.2%. The density of the products varied from 0.71 g/mL up to 0.79 g/mL with a correlated change of the hydrogen to carbon atomic ratio from 2.1 down to 1.9. The product quality remained high throughout the extended tests suggesting minimal loss of catalyst activity through the test. These tests provided the data needed to assess the quality of liquid fuel products obtained from the bioCRACK process as well as the activity of the catalyst for comparison with products obtained from hydrotreated fast pyrolysis bio-oils from fluidized-bed operation.« less

DEVELOPMENT OF ATTRITION RESISTANT IRON-BASED FISCHER-TROPSCH CATALYSTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adeyinka A. Adeyiga

2001-09-01

The Fischer-Tropsch (F-T) reaction provides a way of converting coal-derived synthesis gas (CO+H{sub 2}) to liquid fuels. Since the reaction is highly exothermic, one of the major problems in control of the reaction is heat removal. Recent work has shown that the use of slurry bubble column reactors (SBCRs) can largely solve this problem. The use of iron-based catalysts is attractive not only due to their low cost and ready availability, but also due to their high water-gas shift activity which makes it possible to use these catalysts with low H{sub 2}/CO ratios. However, a serious problem with use ofmore » Fe catalysts in a SBCR is their tendency to undergo attrition. This can cause fouling/plugging of downstream filters and equipment, makes the separation of catalyst from the oil/wax product very difficult if not impossible, and results in a steady loss of catalyst from the reactor. Recently, fundamental understanding of physical attrition is being addressed by incorporating suitable binders into the catalyst recipe. This has resulted in the preparation of a spray dried Fe-based catalyst having aps of 70 mm with high attrition resistance. This Fe-based attrition resistant, active and selective catalyst gave 95% CO conversion through 125 hours of testing in a fixed-bed at 270 C, 1.48 MPa, H{sub 2}/CO=0.67 and 2.0 NL/g-cat/h with C{sub 5}{sup +} selectivity of >78% and methane selectivity of <5%. However, further development of the catalyst is needed to address the chemical attrition due to phase changes that any Fe-catalyst goes through potentially causing internal stresses within the particle and resulting in weakening, spalling or cracking. The objective of this research is to develop robust iron-based Fischer-Tropsch catalysts that have suitable activity, selectivity and stability to be used in the slurry bubble column reactor. Specifically we aim to develop to: (i) improve the performance and preparation procedure of the high activity, high attrition resistant, high alpha iron-based catalysts synthesized at Hampton University, (ii) seek improvements in the catalyst performance through variations in process conditions, pretreatment procedures and/or modifications in catalyst preparation steps and (iii) investigate the performance in a slurry reactor. The effort during the reporting period has been devoted to attrition study of the iron-based catalysts. Precipitated silica appeared to decrease attrition resistance of spray-dried iron FT catalysts. It was found that the catalyst with precipitated silica content at around 12wt% showed the lowest attrition resistance. The results of net change in volume moment and catalyst morphology showed supporting evidences to the attrition results. Catalysts with low attrition resistance generated more fines loss, had higher net change in volume moment and showed more breakage of particles. BET surface area and pore volume of this catalyst series fluctuated; therefore no conclusion can be drawn from the data obtained. However, catalyst with no precipitated silica showed the lowest in BET surface area and pore volume, as expected. Addition of precipitated silica to the catalysts had no effect to the phase changes of iron that could have significant influence to catalyst attrition. The presence of precipitated silica is needed for enhancing catalyst surface area; however, the amount of silica added should be compromising with attrition resistance of catalysts.« less

Catalyst and Process Design for the Continuous Manufacture of Rare Sugar Alcohols by Epimerization-Hydrogenation of Aldoses.

PubMed

Lari, Giacomo M; Gröninger, Olivier G; Li, Qiang; Mondelli, Cecilia; López, Núria; Pérez-Ramírez, Javier

2016-12-20

Sugar alcohols are applied in the food, pharmaceutical, polymer, and fuel industries and are commonly obtained by reduction of the corresponding saccharides. In view of the rarity of some sugar substrates, epimerization of a readily available monosaccharide has been proposed as a solution, but an efficient catalytic system has not yet been identified. Herein, a molybdenum heteropolyacid-based catalyst is developed to transform glucose, arabinose, and xylose into less-abundant mannose, ribose, and lyxose, respectively. Adsorption of molybdic acid onto activated carbon followed by ion exchange to the cesium form limits leaching of the active phase, which greatly improves the catalyst stability over 24 h on stream. The hydrogenation of mixtures of epimers is studied over ruthenium catalysts, and it is found that the precursor to the desired polyol is advantageously converted with faster kinetics. This is explained by density functional theory on the basis of its more favorable adsorption on the metal surface and the lower energy barrier for the addition of a hydrogen atom to the primary carbon atom. Finally, different designs for a continuous process for the conversion of glucose into mannitol are studied, and it is uncovered that two reactors in series with one containing the epimerization catalyst and the other containing a mixture of the epimerization and hydrogenation catalysts increases the mannitol/sorbitol ratio to 1.5 from 1 for a single mixed-bed reactor. This opens a prospective route to the efficient valorization of renewables to added-value chemicals. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Catalyst support structure, catalyst including the structure, reactor including a catalyst, and methods of forming same

DOEpatents

Van Norman, Staci A.; Aston, Victoria J.; Weimer, Alan W.

2017-05-09

Structures, catalysts, and reactors suitable for use for a variety of applications, including gas-to-liquid and coal-to-liquid processes and methods of forming the structures, catalysts, and reactors are disclosed. The catalyst material can be deposited onto an inner wall of a microtubular reactor and/or onto porous tungsten support structures using atomic layer deposition techniques.

Apparatus and methods for direct conversion of gaseous hydrocarbons to liquids

DOEpatents

Kong, Peter C.; Lessing, Paul A.

2006-04-25

A chemical reactor for direct conversion of hydrocarbons includes a dielectric barrier discharge plasma cell and a solid oxide electrochemical cell in fluid communication therewith. The discharge plasma cell comprises a pair of electrodes separated by a dielectric material and passageway therebetween. The electrochemical cell comprises a mixed-conducting solid oxide electrolyte membrane tube positioned between a porous cathode and a porous anode, and a gas inlet tube for feeding oxygen containing gas to the porous cathode. An inlet is provided for feeding hydrocarbons to the passageway of the discharge plasma cell, and an outlet is provided for discharging reaction products from the reactor. A packed bed catalyst may optionally be used in the reactor to increase efficiency of conversion. The reactor can be modified to allow use of a light source for directing ultraviolet light into the discharge plasma cell and the electrochemical cell.

Method for direct conversion of gaseous hydrocarbons to liquids

DOEpatents

Kong, Peter C.; Lessing, Paul A.

2006-03-07

A chemical reactor for direct conversion of hydrocarbons includes a dielectric barrier discharge plasma cell and a solid oxide electrochemical cell in fluid communication therewith. The discharge plasma cell comprises a pair of electrodes separated by a dielectric material and passageway therebetween. The electrochemical cell comprises a mixed-conducting solid oxide electrolyte membrane tube positioned between a porous cathode and a porous anode, and a gas inlet tube for feeding oxygen containing gas to the porous cathode. An inlet is provided for feeding hydrocarbons to the passageway of the discharge plasma cell, and an outlet is provided for discharging reaction products from the reactor. A packed bed catalyst may optionally be used in the reactor to increase efficiency of conversion. The reactor can be modified to allow use of a light source for directing ultraviolet light into the discharge plasma cell and the electrochemical cell.

Plated nickel wire mesh makes superior catalyst bed

NASA Technical Reports Server (NTRS)

Sill, M.

1965-01-01

Porous nickel mesh screen catalyst bed produces gas evolution in hydrogen peroxide thrust chambers used for attitude control of space vehicles. The nickel wire mesh disks in the catalyst bed are plated in rugose form with a silver-gold coating.

Method of Heating a Foam-Based Catalyst Bed

NASA Technical Reports Server (NTRS)

Fortini, Arthur J.; Williams, Brian E.; McNeal, Shawn R.

2009-01-01

A method of heating a foam-based catalyst bed has been developed using silicon carbide as the catalyst support due to its readily accessible, high surface area that is oxidation-resistant and is electrically conductive. The foam support may be resistively heated by passing an electric current through it. This allows the catalyst bed to be heated directly, requiring less power to reach the desired temperature more quickly. Designed for heterogeneous catalysis, the method can be used by the petrochemical, chemical processing, and power-generating industries, as well as automotive catalytic converters. Catalyst beds must be heated to a light-off temperature before they catalyze the desired reactions. This typically is done by heating the assembly that contains the catalyst bed, which results in much of the power being wasted and/or lost to the surrounding environment. The catalyst bed is heated indirectly, thus requiring excessive power. With the electrically heated catalyst bed, virtually all of the power is used to heat the support, and only a small fraction is lost to the surroundings. Although the light-off temperature of most catalysts is only a few hundred degrees Celsius, the electrically heated foam is able to achieve temperatures of 1,200 C. Lower temperatures are achievable by supplying less electrical power to the foam. Furthermore, because of the foam s open-cell structure, the catalyst can be applied either directly to the foam ligaments or in the form of a catalyst- containing washcoat. This innovation would be very useful for heterogeneous catalysis where elevated temperatures are needed to drive the reaction.

Steam Reforming of Acetic Acid over Co-Supported Catalysts: Coupling Ketonization for Greater Stability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davidson, Stephen D.; Spies, Kurt A.; Mei, Donghai

We report on the markedly improved stability of a novel 2-bed catalytic system, as compared to a conventional 1-bed steam reforming catalyst, for the production of H2 from acetic acid. The 2-bed catalytic system comprises of i) a basic oxide ketonization catalyst for the conversion of acetic acid to acetone, and a ii) Co-based steam reforming catalyst, both catalytic beds placed in sequence within the same unit operation. Steam reforming catalysts are particularly prone to catalytic deactivation when steam reforming acetic acid, used here as a model compound for the aqueous fraction of bio-oil. Catalysts comprising MgAl2O4, ZnO, CeO2, andmore » activated carbon (AC) both with and without Co-addition were evaluated for conversion of acetic acid and acetone, its ketonization product, in the presence of steam. It was found that over the bare oxide support only ketonization activity was observed and coke deposition was minimal. With addition of Co to the oxide support steam reforming activity was facilitated and coke deposition was significantly increased. Acetone steam reforming over the same Co-supported catalysts demonstrated more stable performance and with less coke deposition than with acetic acid feedstock. DFT analysis suggests that over Co surface CHxCOO species are more favorably formed from acetic acid versus acetone. These CHxCOO species are strongly bound to the Co catalyst surface and could explain the higher propensity for coke formation from acetic acid. Based on these findings, in order to enhance stability of the steam reforming catalyst a dual-bed (2-bed) catalyst system was implemented. Comparing the 2-bed and 1-bed (Co-supported catalyst only) systems under otherwise identical reaction conditions the 2-bed demonstrated significantly improved stability and coke deposition was decreased by a factor of 4.« less

A new generation of zirconia supported metal oxide catalysts for converting low grade renewable feedstocks to biodiesel.

PubMed

Kim, Manhoe; DiMaggio, Craig; Salley, Steven O; Simon Ng, K Y

2012-08-01

A new class of zirconia supported mixed metal oxides (ZnO-TiO(2)-Nd(2)O(3)/ZrO(2) and ZnO-SiO(2)-Yb(2)O(3)/ZrO(2)) has demonstrated the ability to convert low quality, high free fatty acid (FFA) bio-oils into biodiesel. Pelletized catalysts of ZrO(2) supported metal oxides were prepared via a sol-gel process and tested in continuous flow packed bed reactors for up to 6 months. In a single pass, while operating at mild to moderate reaction conditions, 195 °C and 300 psi, these catalysts can perform simultaneous esterification and transesterification reactions on feedstock of 33% FFA and 67% soybean oil to achieve FAME yields higher than 90%. Catalytic activity of the ZrO(2) supported metal oxide catalysts was highly dependent on the metal oxide composition. These heterogeneous catalysts will enable biodiesel manufacturers to avoid problems inherent in homogeneous processes, such as separation and washing, corrosive conditions, and excessive methanol usage. Copyright © 2012 Elsevier Ltd. All rights reserved.

Production of biofuel from waste cooking palm oil using nanocrystalline zeolite as catalyst: process optimization studies.

PubMed

Taufiqurrahmi, Niken; Mohamed, Abdul Rahman; Bhatia, Subhash

2011-11-01

The catalytic cracking of waste cooking palm oil to biofuel was studied over different types of nano-crystalline zeolite catalysts in a fixed bed reactor. The effect of reaction temperature (400-500 °C), catalyst-to-oil ratio (6-14) and catalyst pore size of different nanocrystalline zeolites (0.54-0.80 nm) were studied over the conversion of waste cooking palm oil, yields of Organic Liquid Product (OLP) and gasoline fraction in the OLP following central composite design (CCD). The response surface methodology was used to determine the optimum value of the operating variables for maximum conversion as well as maximum yield of OLP and gasoline fraction, respectively. The optimum reaction temperature of 458 °C with oil/catalyst ratio=6 over the nanocrystalline zeolite Y with pore size of 0.67 nm gave 86.4 wt% oil conversion, 46.5 wt% OLP yield and 33.5 wt% gasoline fraction yield, respectively. The experimental results were in agreement with the simulated values within an experimental error of less than 5%. Copyright © 2011 Elsevier Ltd. All rights reserved.

Continuous Flow Aerobic Alcohol Oxidation Reactions Using a Heterogeneous Ru(OH)x/Al2O3 Catalyst

PubMed Central

2015-01-01

Ru(OH)x/Al2O3 is among the more versatile catalysts for aerobic alcohol oxidation and dehydrogenation of nitrogen heterocycles. Here, we describe the translation of batch reactions to a continuous-flow method that enables high steady-state conversion and single-pass yields in the oxidation of benzylic alcohols and dehydrogenation of indoline. A dilute source of O2 (8% in N2) was used to ensure that the reaction mixture, which employs toluene as the solvent, is nonflammable throughout the process. A packed bed reactor was operated isothermally in an up-flow orientation, allowing good liquid–solid contact. Deactivation of the catalyst during the reaction was modeled empirically, and this model was used to achieve high conversion and yield during extended operation in the aerobic oxidation of 2-thiophene methanol (99+% continuous yield over 72 h). PMID:25620869

Immobilized biocatalytic process development and potential application in membrane separation: a review.

PubMed

Chakraborty, Sudip; Rusli, Handajaya; Nath, Arijit; Sikder, Jaya; Bhattacharjee, Chiranjib; Curcio, Stefano; Drioli, Enrico

2016-01-01

Biocatalytic membrane reactors have been widely used in different industries including food, fine chemicals, biological, biomedical, pharmaceuticals, environmental treatment and so on. This article gives an overview of the different immobilized enzymatic processes and their advantages over the conventional chemical catalysts. The application of a membrane bioreactor (MBR) reduces the energy consumption, and system size, in line with process intensification. The performances of MBR are considerably influenced by substrate concentration, immobilized matrix material, types of immobilization and the type of reactor. Advantages of a membrane associated bioreactor over a free-enzyme biochemical reaction, and a packed bed reactor are, large surface area of immobilization matrix, reuse of enzymes, better product recovery along with heterogeneous reactions, and continuous operation of the reactor. The present research work highlights immobilization techniques, reactor setup, enzyme stability under immobilized conditions, the hydrodynamics of MBR, and its application, particularly, in the field of sugar, starch, drinks, milk, pharmaceutical industries and energy generation.

Enhanced protection of PDMS-embedded palladium catalysts by co-embedding of sulphide-scavengers.

PubMed

Comandella, Daniele; Ahn, Min Hyung; Kim, Hojeong; Mackenzie, Katrin

2017-12-01

For Pd-containing hydrodechlorination catalysts, coating with poly(dimethyl siloxane) (PDMS) was proposed earlier as promising protection scheme against poisoning. The PDMS coating can effectively repel non-permeating poisons (such as SO 3 2- ) retaining the hydrodechlorination Pd activity. In the present study, the previously achieved protection efficiency was enhanced by incorporation of sulphide scavengers into the polymer. The embedded scavengers were able to bind permeating non-ionic poisons (such as H 2 S) during their passage through PDMS prior to Pd contact which ensured an extended catalyst lifetime. Three scavenger types forming non-permeable sulphur species from H 2 S - alkaline, oxidative or iron-based compounds - were either incorporated into single-layer coats around individual Pd/Al 2 O 3 particles or into a second layer above Pd-containing PDMS films (Pd-PDMS). Hydrodechlorination and hydrogenation were chosen as model reactions, carried out in batch and continuous-flow reactors. Batch tests with all scavenger-containing catalysts showed extended Pd protection compared to scavenger-free catalysts. Solid alkaline compounds (Ca(OH) 2 , NaOH, CaO) and MnO 2 showed the highest instantaneous scavenger efficiencies (retained Pd activity=30-60%), while iron-based catalysts, such as nano zero-valent iron (nZVI) or ferrocene (FeCp 2 ), proved less efficient (1-10%). When stepwise poisoning was applied, the protection efficiency of iron-based and oxidizing compounds was higher in the long term than that of alkaline solids. Long-term experiments in mixed-flow reactors were performed with selected scavengers, revealing the following trend of protection efficiency: CaO 2 >Ca(OH) 2 >FeCp 2 . Under field-simulating conditions using a fixed-bed reactor, the combination of sulphide pre-oxidation in the water phase by H 2 O 2 and local scavenger-enhanced Pd protection was successful. The oxidizing agent H 2 O 2 does not disturb the Pd-catalysed reduction, while the PDMS-incorporated scavenger considerably extends the catalyst life in the presence of H 2 S. This work demonstrates that the scavenger-based protection strategy is an effective means to increase the resistance of PDMS-embedded Pd against permeating poisons. Copyright © 2017. Published by Elsevier B.V.

40 CFR 60.395 - Reporting and recordkeeping requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... temperature (or the gas temperature upstream and downstream of the catalyst bed), the total mass of VOC per... temperature upstream and downstream of the incinerator catalyst bed during coating operations for catalytic... which the average temperature immediately before the catalyst bed, when the coating system is...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Xianhui; Ngo, Huong T.; Walker, Devin M.

The performance of catalytic tri-reforming under industrially relevant situations (e.g., pellet catalysts, pressurized reactor) was investigated using surrogate biogas as the feedstock. Tri-reforming using Ni/Mg/Ce 0.6Zr 0.4O 2/Al 2O 3 pellet catalysts was studied in a bench scale fixed-bed reactor. The feed molar ratio for CH 4: CO 2: air was fixed as 1.0: 0.70: 0.95. The effects of temperature (800 – 860 °C), pressure (1 – 6 bar), and H 2O/CH 4 molar feed ratio (0.23 – 0.65) were examined. Pressure has substantial impact on the reaction and transport rates and equilibrium conversions, making it a key variable. Atmore » 860 °C, CO 2 conversion increased from 4 to 61% and H 2/CO molar ratio decreased from 2.0 to 1.1 as the pressure changed from 1 to 6 bar. CO 2 conversion and H 2/CO molar ratio were also influenced by the temperature and H 2O/CH 4 molar ratio. At 3 bar, CO 2 conversion varied between 4 and 43% and the H 2/CO molar ratio varied between 1.2 and 1.9 as the temperature changed from 800 to 860 °C. At 3 bar and 860 °C, CO 2 conversion decreased from 35 to 8% and H 2/CO molar ratio increased from 1.7 to 2.4 when the H 2O/CH 4 molar ratio was increased from 0.23 to 0.65. This work demonstrates that the tri-reforming technology is feasible for converting biogas under scaled-up conditions in a fixed-bed reactor.« less

Etherification process

DOEpatents

Smith, L.A. Jr.; Hearn, D.; Jones, E.M. Jr.

1990-08-21

A liquid phase process is described for oligomerization of C[sub 4] and C[sub 5] isoolefins or the etherification thereof with C[sub 1] to C[sub 6] alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300 F wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled. 2 figs.

Method for conducting exothermic reactions

DOEpatents

Smith, L. Jr.; Hearn, D.; Jones, E.M. Jr.

1993-01-05

A liquid phase process for oligomerization of C[sub 4] and C[sub 5] isoolefins or the etherification thereof with C[sub 1] to C[sub 6] alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300 F. wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

Method for conducting exothermic reactions

DOEpatents

Smith, Jr., Lawrence; Hearn, Dennis; Jones, Jr., Edward M.

1993-01-01

A liquid phase process for oligomerization of C.sub.4 and C.sub.5 isoolefins or the etherification thereof with C.sub.1 to C.sub.6 alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120.degree. to 300.degree. F. wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

Oligomerization process

DOEpatents

Smith, L.A. Jr.; Hearn, D.; Jones, E.M. Jr.

1991-03-26

A liquid phase process is described for oligomerization of C[sub 4] and C[sub 5] isoolefins or the etherification thereof with C[sub 1] to C[sub 6] alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300 F wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled. 2 figures.

Effect of H2O2 injection patterns on catalyst bed characteristics

NASA Astrophysics Data System (ADS)

Kang, Hongjae; Lee, Dahae; Kang, Shinjae; Kwon, Sejin

2017-01-01

The decomposition process of hydrogen peroxide can be applied to a bipropellant thruster, as well as to monopropellant thruster. To provide a framework for the optimal design of the injector and catalyst bed depending on a type of thruster, this research scrutinizes the effect of injection patterns of the propellant on the performance of the catalyst bed. A showerhead injector and impinging jet injector were tested with a 50 N monopropellant thruster. Manganese oxide/γ-alumina catalyst and manganese oxide/lanthanum-doped alumina catalyst were prepared and tested. The showerhead injector provided a fast response time, suitable for pulse mode operation. The impinging jet injector mitigated the performance instability and catalyst attrition that is favorable for large scale bipropellant thrusters. The design of a dual catalyst bed was conceptually proposed based on the data obtained from firing tests.

Pilot-scale evaluation of a novel TiO2-supported V2O5 catalyst for DeNOx at low temperatures at a waste incinerator.

PubMed

Jung, Hyounduk; Park, Eunseuk; Kim, Minsu; Jurng, Jongsoo

2017-03-01

The removal of NOx by catalytic technology at low temperatures is significant for treatment of flue gas in waste incineration plants, especially at temperatures below 200°C. A novel highly active TiO 2 -supported vanadium oxide catalyst at low temperatures (200-250°C) has been developed for the selective catalytic reduction (SCR) de-NOx process with ammonia. The catalyst was evaluated in a pilot-scale equipment, and the results were compared with those obtained in our previous work using laboratory scale (small volume test) equipment as well as bench-scale laboratory equipment. In the present work, we have performed our experiments in pilot scale equipment using a part of effluent flue gas that was obtained from flue gas cleaning equipment in a full-scale waste incineration plant in South Korea. Based on our previous work, we have prepared a TiO 2 -supported V 2 O 5 catalyst coated (with a loading of 7wt% of impregnated V 2 O 5 ) on a honeycomb cordierite monolith to remove NOx from a waste incinerator flue gas at low temperatures. The NOx (nitrogen oxides) removal efficiency of the SCR catalyst bed was measured in a catalyst fixed-bed reactor (flow rate: 100m 3 h -1 ) using real exhaust gas from the waste incinerator. The experimental results showed that the V 2 O 5 /TiO 2 SCR catalyst exhibited good DeNOx performance (over 98% conversion at an operating temperature of 300°C, 95% at 250°C, and 70% at 200°C), and was much better than the performance of commercial SCR catalysts (as low as 55% conversion at 250°C) under the same operating conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Microwave In-situ Regeneration of Cu-Mn-Ce/ZSM Catalyst Adsorbed Toluene and Distribution of Bed Temperature].

PubMed

Hu, Xue-jiao; Bo, Long-li; Liang, Xin-xin; Meng, Hai-long

2015-08-01

Microwave in-situ regeneration of Cu-Mn-Ce/ZSM catalyst adsorbed toluene, distribution of fixed bed temperature, adsorption breakthrough curves of the catalyst after several regenerations and characterizations of the catalyst by BET and SEM were investigated in this study. The research indicated that regeneration effect of the catalyst adsorbed was excellent under conditions of microwave power 117 W, air flow 0.5 m3 x h(-1) and catalyst dosage of 800 g. Toluene desorbed was oxidized onto the surface of the catalyst, and the adsorption capacity of the catalyst was recovered simultaneously. Under microwave irradiation, bed temperature decreased slowly from inside to outside in horizontal level, and increased gradually from down to up in vertical level so that the highest temperature reached 250-350 degrees C at the upper sites of the bed. Sintering and agglomeration occurred on the surface of the catalyst in the course of regeneration so that the special surface area and micropore volume of the catalyst were reduced and breakthrough time was shortened, which was verified by six adsorption breakthrough curves and related characteristics of the catalyst. However, the structure of the catalyst was steady after two regenerations, and adsorption breakthrough time was kept at 70 min. The result showed that the changes of surface morphology and pore structure were positively correlated with the distribution of bed temperature.

Ni/MgAlO regeneration for catalytic wet air oxidation of an azo-dye in trickle-bed reaction.

PubMed

Vallet, Ana; Ovejero, Gabriel; Rodríguez, Araceli; Peres, José A; García, Juan

2013-01-15

Active nickel catalysts (7 wt%) supported over Mg-Al mixed oxides have been recently developed and it has also been demonstrated that they are also highly selective in Catalytic Wet air Oxidation (CWAO) of dyes. CWAO of Chromotrope 2R (C2R) has been studied using a trickle bed reactor employing temperatures from 100 to 180 °C, liquid flow rates from 0.1 to 0.7 mL min(-1) and initial dye concentration from 10 to 50 ppm. Total pressure and air flow were 25 bar and 300 mL min(-1), respectively. The catalyst showed a very stable activity up to 24 h on stream with an average TOC conversion of 82% at 150 °C and T(r)=0.098 g(Ni) min mL(-1). After the reaction, a 1.1 wt% C of carbonaceous deposit is formed onto the catalyst and a diminution of 30% of the surface area with respect of the fresh catalyst was observed. An increase in the space time gave higher TOC conversions up to T(r)=0.098 g(Ni) min mL(-1), attaining values of 80% at 180 °C. The performance of TOC and dye removal does not decrease after two regeneration cycles. In total, a 57 h effective reaction has been carried out with no loss of catalytic activity. Copyright © 2012 Elsevier B.V. All rights reserved.

Six-flow operations for catalyst development in Fischer-Tropsch synthesis: Bridging the gap between high-throughput experimentation and extensive product evaluation

NASA Astrophysics Data System (ADS)

Sartipi, Sina; Jansma, Harrie; Bosma, Duco; Boshuizen, Bart; Makkee, Michiel; Gascon, Jorge; Kapteijn, Freek

2013-12-01

Design and operation of a "six-flow fixed-bed microreactor" setup for Fischer-Tropsch synthesis (FTS) is described. The unit consists of feed and mixing, flow division, reaction, separation, and analysis sections. The reactor system is made of five heating blocks with individual temperature controllers, assuring an identical isothermal zone of at least 10 cm along six fixed-bed microreactor inserts (4 mm inner diameter). Such a lab-scale setup allows running six experiments in parallel, under equal feed composition, reaction temperature, and conditions of separation and analysis equipment. It permits separate collection of wax and liquid samples (from each flow line), allowing operation with high productivities of C5+ hydrocarbons. The latter is crucial for a complete understanding of FTS product compositions and will represent an advantage over high-throughput setups with more than ten flows where such instrumental considerations lead to elevated equipment volume, cost, and operation complexity. The identical performance (of the six flows) under similar reaction conditions was assured by testing a same catalyst batch, loaded in all microreactors.

Autothermal reforming of aliphatic and aromatic hydrocarbon liquids

NASA Technical Reports Server (NTRS)

Flytzani-Stephanopoulos, M.; Voecks, G. E.

1983-01-01

Results are presented from a study of the autothermal reforming of paraffins and aromatics over nickel catalysts. The trials were performed to examine the carbon products that appear when steam is passed over hydrocarbon liquids to form H2-rich gases, i.e., the autothermal process (ATR). Attention was given to n-hexane, n-tetradecane, benzene, and benzene solutions of naphthalene with reactant preheat to 1000-1150 F. The carbon-formation limit was sought as a function of the steam-to-carbon and oxygen to carbon molar ratios at constant pressure and the preheat temperatures. The catalyst bed was examined after each trial to identify the locations and types of carbon formed using SEM, thermal gravimetric analysis, and X ray diffraction techniques. The hydrocarbon fuels each had a separate temperature and reaction profile, as well as carbon formation characteristics. No carbon formation was observed in the upper layer of the reactor bed, while both gas phase and surface-grown deposits were present in the lower part. The results are concluded of use in the study of No. 2 fuel oil for ATR feedstock.

Central composite design optimization of pilot plant fluidized-bed heterogeneous Fenton process for degradation of an azo dye.

PubMed

Aghdasinia, Hassan; Bagheri, Rasoul; Vahid, Behrouz; Khataee, Alireza

2016-11-01

Optimization of Acid Yellow 36 (AY36) degradation by heterogeneous Fenton process in a recirculated fluidized-bed reactor was studied using central composite design (CCD). Natural pyrite was applied as the catalyst characterized by X-ray diffraction and scanning electron microscopy. The CCD model was developed for the estimation of degradation efficiency as a function of independent operational parameters including hydrogen peroxide concentration (0.5-2.5 mmol/L), initial AY36 concentration (5-25 mg/L), pH (3-9) and catalyst dosage (0.4-1.2 mg/L). The obtained data from the model are in good agreement with the experimental data (R(2 )= 0.964). Moreover, this model is applicable not only to determine the optimized experimental conditions for maximum AY36 degradation, but also to find individual and interactive effects of the mentioned parameters. Finally, gas chromatography-mass spectroscopy (GC-MS) was utilized for the identification of some degradation intermediates and a plausible degradation pathway was proposed.

40 CFR 60.584 - Monitoring of operations and recordkeeping requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the gas temperatures both upstream and downstream of the catalyst bed and shall comply with the... average gas temperature both upstream and downstream of the catalyst bed. After the performance test, the... average temperature of the gas stream before the catalyst bed is more than 28 °C below the average...

40 CFR 60.495 - Reporting and recordkeeping requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... catalyst bed), the total mass of VOC per volume of coating solids before and after the incinerator, capture... device immediately before the catalyst bed is more than 28 °C below the average temperature of the device immediately before the catalyst bed during the most recent performance test at which destruction efficiency...

40 CFR 60.455 - Reporting and recordkeeping requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... upstream and downstream of the catalyst bed), and (iv) A description of the method used to establish the... temperature recorded immediately before the catalyst bed is more than 28 °C (50 °F) below the average... the average temperature difference across the catalyst bed is less than 80 percent of the average...

40 CFR 60.315 - Reporting and recordkeeping requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... downstream of the catalyst bed), and (iv) A description of the method used to establish the amount of VOC's... the average temperature of the device immediately before the catalyst bed is more than 28 °C below the average temperature of the device immediately before the catalyst bed during the most recent performance...

Effect of carbon supports on RhRe bifunctional catalysts for selective hydrogenolysis of tetrahydropyran-2-methanol

DOE PAGES

Karanjkar, Pranav U.; Burt, Samuel P.; Chen, Xiaoli; ...

2016-09-12

Tetrahydropyran-2-methanol undergoes selective C–O–C hydrogenolysis to produce 1,6-hexanediol using a bifunctional RhRe (reducible metal with an oxophilic promoter) catalyst supported on Vulcan XC-72 carbon (VXC) with >90% selectivity. This RhRe/VXC catalyst is stable over 40 h of reaction in a continuous flow fixed bed reactor. The hydrogenolysis activity of RhRe/VXC is two orders-of-magnitude higher than that of RhRe supported on Norit Darco 12X40 activated carbon (NDC). STEM–EDS analysis reveals that, compared to the RhRe/VXC catalyst, the Re and Rh component metals are segregated on the surface of the low activity RhRe/NDC catalyst, suggesting that Rh and Re in close proximitymore » (“bimetallic” particles) are required for an active hydrogenolysis catalyst. Differences in metal distribution on the carbon surfaces are, in turn, linked to the properties of the carbons: NDC has both a higher surface area and surface oxygen content. Thus, the low areal density of Rh and Re precursors on the high area NDC and/or interactions of the precursors with its O functional groups may interfere with the formation of the bimetallic species required for an active catalyst.« less

Performance of Ni/dolomite pellet catalyst on gas distribution from cassava rhizome gasification with a modular fixed-bed gasifier.

PubMed

Sricharoenchaikul, V; Atong, D; Sornkade, P; Nisamaneenate, J

2017-05-01

Thermal conversion of cassava rhizome was performed using a modular downdraft gasifier with the addition of Ni-based catalysts as promising tar eliminating and produced gas upgrading techniques. The activities of a synthesized 5% Ni/dolomite pellet catalyst prepared by impregnation method were investigated in a secondary reactor downstream of the gasifier. High reforming activity of the Ni/dolomite pellet catalyst on tar reduction was achieved. The conversion to H 2 and CO was improved via steam reforming of methane and char reaction with CO 2 . Moreover, the formation of CH 4 and C x H y was diminished through the tar or condensable hydrocarbon reformed on the catalyst surface. The carbon and hydrogen conversions of cassava rhizome with prepared catalyst were 83.79% and 61.78%, respectively, at an air flow rate of 1.98 m 3 /hr. At this condition, tar formation was low, while the lower heating value was 4.39 MJ/m 3 and H 2 to CO molar ratio was 1.22. Generally, the addition of a catalyst not only enhanced gas production, but also reduced tar and particulate matter generation; thus, its implementation should help lessen the pollution control requirement and cost of operation, while allowing higher quality fuel gas production.

Turning Biodiesel Waste Glycerol into 1,3-Propanediol: Catalytic Performance of Sulphuric acid-Activated Montmorillonite Supported Platinum Catalysts in Glycerol Hydrogenolysis.

PubMed

Samudrala, Shanthi Priya; Kandasamy, Shalini; Bhattacharya, Sankar

2018-05-10

Direct C-O hydrogenolysis of bioglycerine to produce 1,3-propanediol selectively is a vital technology that can expand the scope of biodiesel industry and green chemical production from biomass. Herein we report sulphuric acid-activated montmorillonite clay supported platinum nanoparticles as highly effective solid acid catalysts for the selective production of 1,3-propanediol from glycerol. The catalytic performances of the catalysts were investigated in the hydrogenolysis of glycerol with a fixed bed reactor under ambient pressure. The results were found promising and showed that the activation of montmorillonite by sulphuric acid incorporated Brønsted acidity in the catalyst and significantly improved the selectivity to 1,3-propanediol. The catalytic performance of different platinum loaded catalysts was examined and 2 wt% Pt/S-MMT catalyst presented superior activity among others validating 62% 1,3-propanediol selectivity at 94% glycerol conversion. The catalytic activity of 2Pt/S-MMT was systematically investigated under varying reaction parameters including reaction temperature, hydrogen flow rate, glycerol concentration, weight hourly space velocity, and contact time to derive the optimum conditions for the reaction. The catalyst stability, reusability and structure-activity correlation were also elucidated. The high performance of the catalyst could be ascribed to well disperse Pt nanoparticles immobilized on acid-activated montmorillonite, wider pore-structure and appropriate acid sites of the catalyst.

Bimetallic catalysts for continuous catalytic wet air oxidation of phenol.

PubMed

Fortuny, A; Bengoa, C; Font, J; Fabregat, A

1999-01-29

Catalytic wet oxidation has proved to be effective at eliminating hazardous organic compounds, such as phenol, from waste waters. However, the lack of active long-life oxidation catalysts which can perform in aqueous phase is its main drawback. This study explores the ability of bimetallic supported catalysts to oxidize aqueous phenol solutions using air as oxidant. Combinations of 2% of CoO, Fe2O3, MnO or ZnO with 10% CuO were supported on gamma-alumina by pore filling, calcined and later tested. The oxidation was carried out in a packed bed reactor operating in trickle flow regime at 140 degrees C and 900 kPa of oxygen partial pressure. Lifetime tests were conducted for 8 days. The pH of the feed solution was also varied. The results show that all the catalysts tested undergo severe deactivation during the first 2 days of operation. Later, the catalysts present steady activity until the end of the test. The highest residual phenol conversion was obtained for the ZnO-CuO, which was significantly higher than that obtained with the 10% CuO catalyst used as reference. The catalyst deactivation is related to the dissolution of the metal oxides from the catalyst surface due to the acidic reaction conditions. Generally, the performance of the catalysts was better when the pH of the feed solution was increased.

Pyrolysis of waste tyres: A review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Paul T., E-mail: p.t.williams@leeds.ac.uk

2013-08-15

Graphical abstract: - Highlights: • Pyrolysis of waste tyres produces oil, gas and char, and recovered steel. • Batch, screw kiln, rotary kiln, vacuum and fluidised-bed are main reactor types. • Product yields are influenced by reactor type, temperature and heating rate. • Pyrolysis oils are complex and can be used as chemical feedstock or fuel. • Research into higher value products from the tyre pyrolysis process is reviewed. - Abstract: Approximately 1.5 billion tyres are produced each year which will eventually enter the waste stream representing a major potential waste and environmental problem. However, there is growing interest inmore » pyrolysis as a technology to treat tyres to produce valuable oil, char and gas products. The most common reactors used are fixed-bed (batch), screw kiln, rotary kiln, vacuum and fluidised-bed. The key influence on the product yield, and gas and oil composition, is the type of reactor used which in turn determines the temperature and heating rate. Tyre pyrolysis oil is chemically very complex containing aliphatic, aromatic, hetero-atom and polar fractions. The fuel characteristics of the tyre oil shows that it is similar to a gas oil or light fuel oil and has been successfully combusted in test furnaces and engines. The main gases produced from the pyrolysis of waste tyres are H{sub 2}, C{sub 1}–C{sub 4} hydrocarbons, CO{sub 2}, CO and H{sub 2}S. Upgrading tyre pyrolysis products to high value products has concentrated on char upgrading to higher quality carbon black and to activated carbon. The use of catalysts to upgrade the oil to a aromatic-rich chemical feedstock or the production of hydrogen from waste tyres has also been reported. Examples of commercial and semi-commercial scale tyre pyrolysis systems show that small scale batch reactors and continuous rotary kiln reactors have been developed to commercial scale.« less

Design and assembly of a catalyst bed gas generator for the catalytic decomposition of high concentration hydrogen peroxide propellants and the catalytic combustion of hydrocarbon/air mixtures

NASA Technical Reports Server (NTRS)

Lohner, Kevin A. (Inventor); Mays, Jeffrey A. (Inventor); Sevener, Kathleen M. (Inventor)

2004-01-01

A method for designing and assembling a high performance catalyst bed gas generator for use in decomposing propellants, particularly hydrogen peroxide propellants, for use in target, space, and on-orbit propulsion systems and low-emission terrestrial power and gas generation. The gas generator utilizes a sectioned catalyst bed system, and incorporates a robust, high temperature mixed metal oxide catalyst. The gas generator requires no special preheat apparatus or special sequencing to meet start-up requirements, enabling a fast overall response time. The high performance catalyst bed gas generator system has consistently demonstrated high decomposition efficiency, extremely low decomposition roughness, and long operating life on multiple test articles.

Treatment of a non-azo dye aqueous solution by CWAO in continuous reactor using a Ni catalyst derived from hydrotalcite-like precursor.

PubMed

Vallet, Ana; Besson, Michèle; Ovejero, Gabriel; García, Juan

2012-08-15

Catalytic wet air oxidation (CWAO) of a Basic Yellow 11 (BY11) aqueous solution, chosen as a model of a hardly biodegradable non-azo dye was carried out in a continuous-flow trickle-bed reactor, using nickel supported over hydrotalcite precursor calcined at 550°C. An increase in the reaction temperature (120-180°C), and a decrease in dye concentration (1000-3000 ppm) or liquid flow rate (0.1-0.7 mL min(-1)) enhanced the CWAO performance in a 30 and 19% for the variation of the temperature and concentration respectively. After a small leaching observed within the first hours, the catalyst proved to be very stable during the 65-day reaction. The CWAO process was found to be very efficient, achieving BY11 conversion up to 95% and TOC conversion up to 85% at 0.1 mL min(-1) and 180°C under 5 MPa air. Copyright © 2012 Elsevier B.V. All rights reserved.

Feasibility of Ultraviolet Light Emitting Diodes as an Alternative Light Source for Photocatalysis

NASA Technical Reports Server (NTRS)

Levine, Langanf H.; Richards, Jeffrey T.; Soler, Robert; Maxik, Fred; Coutts, Janelle; Wheeler, Raymond M.

2011-01-01

The objective of this study was to determine whether ultraviolet light emitting diodes (UV-LEDs) could serve as an alternative photon source efficiently for heterogeneous photocatalytic oxidation (PCO). An LED module consisting of 12 high-power UV-A LEDs was designed to be interchangeable with a UV-A fluorescent black light blue (BLB) lamp in a Silica-Titania Composite (STC) packed bed annular reactor. Lighting and thermal properties were characterized to assess the uniformity and total irradiant output. A forward current of (I(sub F)) 100 mA delivered an average irradiance of 4.0 m W cm(exp -2), which is equivalent to the maximum output of the BLB, but the irradiance of the LED module was less uniform than that of the BLB. The LED- and BLB-reactors were tested for the oxidization of 50 ppmv ethanol in a continuous flow-through mode with 0.94 sec space time. At the same irradiance, the UV-A LED reactor resulted in a lower PCO rate constant than the UV-A BLB reactor (19.8 vs. 28.6 nM CO2 sec-I), and consequently lower ethanol removal (80% vs. 91%) and mineralization efficiency (28% vs. 44%). Ethanol mineralization increased in direct proportion to the irradiance at the catalyst surface. This result suggests that reduced ethanol mineralization in the LED- reactor could be traced to uneven irradiance over the photocatalyst, leaving a portion of the catalyst was under-irradiated. The potential of UV-A LEDs may be fully realized by optimizing the light distribution over the catalyst and utilizing their instantaneous "on" and "off' feature for periodic irradiation. Nevertheless, the current UV-A LED module had the same wall plug efficiency (WPE) of 13% as that of the UV-A BLB. These results demonstrated that UV-A LEDs are a viable photon source both in terms of WPE and PCO efficiency.

Catalytic wet oxidation of ammonia solution: activity of the nanoscale platinum-palladium-rhodium composite oxide catalyst.

PubMed

Hung, Chang-Mao

2009-04-15

Aqueous solutions of 400-1000 mg/L of ammonia were oxidized in a trickle-bed reactor (TBR) in this study of nanoscale platinum-palladium-rhodium composite oxide catalysts, which were prepared by the co-precipitation of H(2)PtCl(6), Pd(NO(3))(3) and Rh(NO(3))(3). Hardly any of the dissolved ammonia was removed by wet oxidation in the absence of any catalyst, whereas about 99% of the ammonia was reduced during wet oxidation over nanoscale platinum-palladium-rhodium composite oxide catalysts at 503 K in an oxygen partial pressure of 2.0 MPa. A synergistic effect exists in the nanoscale platinum-palladium-rhodium composite structure, which is the material with the highest ammonia reduction activity. The nanometer-sized particles were characterized by TEM, XRD and FTIR. The effect of the initial concentration and reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes.

The influence of calcination temperatures on the acid-based properties and catalytic activity for the 1,3-butadiene synthesis from ethanol/acetaldehyde mixture

NASA Astrophysics Data System (ADS)

Gao, Meixiang; Jiang, Haoxi; Zhang, Minhua

2018-05-01

The influences of the calcination temperature on the catalysts' acid-based properties and catalytic activity for the 1,3-butadiene synthesis from ethanol are investigated. The results show that the 2 wt% ZrO2/Nano-SiO2 calcined at 773 K shows the best performance with the selectivity of 93.18% and conversion of 58.52% when reacted at 593 K, a WHSV of 1.8 h-1 and 3.5:1 volume ratio ethanol-to-acetaldehyde in an atmospheric fixed-bed reactor. Prepared catalysts were characterized by N2 adsorption-desorption, XRD, temperature-programmed desorption of NH3 and CO2, FTIR spectroscopy of adsorbed pyridine and CO2. Based on the relationship between the catalyst activity and its properties, the fact can be presumed that the formation and strength of Zrsbnd Osbnd Si bond determines the acid-based properties of the catalyst. In addition, moderate-intensity weak acid-basic sites are more suitable for ethanol conversion to BD with the amount of acid and basic sites as close as possible.

Atomic layer deposited highly dispersed platinum nanoparticles supported on non-functionalized multiwalled carbon nanotubes for the hydrogenation of xylose to xylitol

NASA Astrophysics Data System (ADS)

Liang, Xinhua; Jiang, Chengjun

2013-09-01

Highly dispersed platinum nanoparticles were deposited on gram quantities of non-functionalized multiwalled carbon nanotubes (MWCNTs) by atomic layer deposition (ALD) in a fluidized bed reactor at 300 °C. (Methylcyclopentadienyl) trimethylplatinum and oxygen were used as precursors. The results of TEM analysis showed that 1.3 nm Pt nanoparticles were highly dispersed on non-functionalized MWCNTs. The porous structures of MWCNTs did not change with the deposition of Pt nanoparticles. For comparison, the commercial 3 wt% Pt/C catalyst was also characterized. The ALD-prepared Pt/MWCNT was used for the hydrogenation of xylose to xylitol. The ALD-prepared Pt/MWCNT showed the best catalytic performance with 100 % conversion of xylose and 99.3 % selectivity to xylitol, compared to commercially available Pt/C, Ru/C, and Raney Ni catalysts. The stability of ALD produced Pt/MWCNT catalyst was higher than that of the commercial Pt/C, due to the presence of surface defects on the MWCNTs and the strong metal-support interaction for the ALD-prepared Pt/MWCNT catalyst.

Continuous hydrogenation of ethyl levulinate to γ-valerolactone and 2-methyl tetrahydrofuran over alumina doped Cu/SiO2 catalyst: the potential of commercialization

NASA Astrophysics Data System (ADS)

Zheng, Junlin; Zhu, Junhua; Xu, Xuan; Wang, Wanmin; Li, Jiwen; Zhao, Yan; Tang, Kangjian; Song, Qi; Qi, Xiaolan; Kong, Dejin; Tang, Yi

2016-07-01

Hydrogenation of levulinic acid (LA) and its esters to produce γ-valerolactone (GVL) and 2-methyl tetrahydrofuran (2-MTHF) is a key step for the utilization of cellulose derived LA. Aiming to develop a commercially feasible base metal catalyst for the production of GVL from LA, with satisfactory activity, selectivity, and stability, Al2O3 doped Cu/SiO2 and Cu/SiO2 catalysts were fabricated by co-precipitation routes in parallel. The diverse physio-chemical properties of these two catalysts were characterized by XRD, TEM, dissociative N2O chemisorptions, and Py-IR methods. The catalytic properties of these two catalysts were systematically assessed in the continuous hydrogenation of ethyl levulinate (EL) in a fixed-bed reactor. The effect of acidic property of the SiO2 substrate on the catalytic properties was investigated. To justify the potential of its commercialization, significant attention was paid on the initial activity, proper operation window, by-products control, selectivity, and stability of the catalyst. The effect of reaction conditions, such as temperature and pressure, on the performance of the catalyst was also thoroughly studied. The development of alumina doped Cu/SiO2 catalyst strengthened the value-chain from cellulose to industrially important chemicals via LA and GVL.

Continuous hydrogenation of ethyl levulinate to γ-valerolactone and 2-methyl tetrahydrofuran over alumina doped Cu/SiO2 catalyst: the potential of commercialization

PubMed Central

Zheng, Junlin; Zhu, Junhua; Xu, Xuan; Wang, Wanmin; Li, Jiwen; Zhao, Yan; Tang, Kangjian; Song, Qi; Qi, Xiaolan; Kong, Dejin; Tang, Yi

2016-01-01

Hydrogenation of levulinic acid (LA) and its esters to produce γ-valerolactone (GVL) and 2-methyl tetrahydrofuran (2-MTHF) is a key step for the utilization of cellulose derived LA. Aiming to develop a commercially feasible base metal catalyst for the production of GVL from LA, with satisfactory activity, selectivity, and stability, Al2O3 doped Cu/SiO2 and Cu/SiO2 catalysts were fabricated by co-precipitation routes in parallel. The diverse physio-chemical properties of these two catalysts were characterized by XRD, TEM, dissociative N2O chemisorptions, and Py-IR methods. The catalytic properties of these two catalysts were systematically assessed in the continuous hydrogenation of ethyl levulinate (EL) in a fixed-bed reactor. The effect of acidic property of the SiO2 substrate on the catalytic properties was investigated. To justify the potential of its commercialization, significant attention was paid on the initial activity, proper operation window, by-products control, selectivity, and stability of the catalyst. The effect of reaction conditions, such as temperature and pressure, on the performance of the catalyst was also thoroughly studied. The development of alumina doped Cu/SiO2 catalyst strengthened the value-chain from cellulose to industrially important chemicals via LA and GVL. PMID:27377401

Catalytic performance of V2O5-MoO3/γ-Al2O3 catalysts for partial oxidation of n-hexane1

NASA Astrophysics Data System (ADS)

Mahmoudian, R.; Khodadadi, Z.; Mahdavi, Vahid; Salehi, Mohammed

2016-01-01

In the current study, a series of V2O5-MoO3 catalyst supported on γ-Al2O3 with various V2O5 and MoO3 loadings was prepared by wet impregnation technique. The characterization of prepared catalysts includes BET surface area, powder X-ray diffraction (XRD), and oxygen chemisorptions. The partial oxidation of n-hexane by air over V2O5-MoO3/γ-Al2O3 catalysts was carried out under flow condition in a fixed bed glass reactor. The effect of V2O5 loading, temperature, MoO3 loading, and n-hexane LHSV on the n-hexane conversion and the product selectivity were investigated. The partial oxygenated products of n-hexane oxidation were ethanol, acetic anhydride, acetic acid, and acetaldehyde. The 10% V2O5-1%MoO3/γ-Al2O3 was found in most active and selective catalyst during partial oxidation of n-hexane. The results indicated that by increasing the temperature, the n-hexane conversion increases as well, although the selectivity of the products passes through a maximum by increasing the temperature.

Catalyst Development for Hydrogen Peroxide Rocket Engines

NASA Technical Reports Server (NTRS)

Morlan, P. W.; Wu, P.-K.; Ruttle, D. W.; Fuller, R. P.; Nejad, A. S.; Anderson, W. E.

1999-01-01

The development of various catalysts of hydrogen peroxide was conducted for the applications of liquid rocket engines. The catalyst development includes silver screen technology, solid catalyst technology, and homogeneous catalyst technology. The silver screen technology development was performed with 85% (by weight) hydrogen peroxide. The results of this investigation were used as the basis for the catalyst design of a pressure-fed liquid-fueled upper stage engine. Both silver-plated nickel 200 screens and pure silver screens were used as the active metal catalyst during the investigation, The data indicate that a high decomposition efficiency (greater than 90%) of 85% hydrogen peroxide can be achieved at a bed loading of 0.5 lbm/sq in/sec with both pure silver and silver plated screens. Samarium oxide coating, however, was found to retard the decomposition process and the catalyst bed was flooded at lower bed loading. A throughput of 200 lbm of hydrogen peroxide (1000 second run time) was tested to evaluate the catalyst aging issue and performance degradation was observed starting at approximately 400 seconds. Catalyst beds of 3.5 inch in diameter was fabricated using the same configuration for a 1,000-lbf rocket engine. High decomposition efficiency was obtained with a low pressure drop across the bed. Solid catalyst using precious metal was also developed for the decomposition of hydrogen peroxide from 85% to 98% by weight. Preliminary results show that the catalyst has a strong reactivity even after 15 minutes of peroxide decomposition. The development effort also includes the homogeneous catalyst technology. Various non-toxic catalysts were evaluated with 98% peroxide and hydrocarbon fuels. The results of open cup drop tests indicate an ignition delay around 11 ms.

The Effect of K and Acidity of NiW-Loaded HY Zeolite Catalyst for Selective Ring Opening of 1-Methylnaphthalene.

PubMed

Lee, You-Jin; Kim, Eun-Sang; Kim, Jeong-Rang; Kim, Joo-Wan; Kim, Tae-Wan; Chae, Ho-Jeong; Kim, Chul-Ung; Lee, Chang-Ha; Jeong, Soon-Yong

2016-05-01

Bi-functional catalysts were prepared using HY zeolites with various SiO2/Al2O3 ratios for acidic function, NiW for metallic function, and K for acidity control. 1-Methylnaphthalene was selected as a model compound for multi-ring aromatics in heavy oil, and its selective ring opening reaction was investigated using the prepared bi-functional catalysts with different levels of acidity in a fixed bed reactor system. In NiW/HY catalysts without K addition, the acidity decreased with the SiO2/Al2O3 mole ratio of the HY zeolite. Ni1.1W1.1/HY(12) catalyst showed the highest acidity but slightly lower yields for the selective ring opening than Ni1.1W1.1/HY(30) catalyst. The acidity of the catalyst seemed to play an important role as the active site for the selective ring opening of 1-methylnaphthalene but there should be some optimum catalyst acidity for the reaction. Catalyst acidity could be controlled between Ni1.1W1.1/HY(12) and Ni1.1W1.1/HY(30) by adding a moderate amount of K to Ni1.1W1.1/HY(12) catalyst. K0.3Ni1.1W1.1/HY(12) catalyst should have the optimum acidity for the selective ring opening. The addition of a moderate amount of K to the NiW/HY catalyst must improve the catalytic performance due to the optimization of catalyst acidity.

Process development and modeling of fluidized-bed reactor with coimmobilized biocatalyst for fuel ethanol production

NASA Astrophysics Data System (ADS)

Sun, May Yongmei

This research focuses on two steps of commercial fuel ethanol production processes: the hydrolysis starch process and the fermentation process. The goal of this research is to evaluate the performance of co-immobilized biocatalysts in a fluidized bed reactor with emphasis on economic and engineering aspects and to develop a predictive mathematical model for this system. The productivity of an FBR is higher than productivity of a traditional batch reactor or CSTR. Fluidized beds offer great advantages over packed beds for immobilized cells when small particles are used or when the reactant feed contains suspended solids. Plugging problems, excessive pressure drops (and thus attrition), or crushing risks may be avoided. No mechanical stirring is required as mixing occurs due to the natural turbulence in the fluidized process. Both enzyme and microorganism are immobilized in one catalyst bead which is called co-immobilization. Inside this biocatalyst matrix, starch is hydrolyzed by the enzyme glucoamylase to form glucose and then converted to ethanol and carbon dioxide by microorganisms. Two biocatalysts were evaluated: (1) co-immobilized yeast strain Saccharomyces cerevisiae and glucoamylase. (2) co-immobilized Zymomonas mobilis and glucoamylase. A co-immobilized biocatalyst accomplishes the simultaneous saccharification and fermentation (SSF process). When compared to a two-step process involving separate saccharification and fermentation stages, the SSF process has productivity values twice that given by the pre-saccharified process when the time required for pre-saccharification (15--25 h) was taken into account. The SSF process should also save capital cost. The information about productivity, fermentation yield, concentration profiles along the bed, ethanol inhibition, et al., was obtained from the experimental data. For the yeast system, experimental results showed that: no apparent decrease of productivity occurred after two and half months, the productivity was 25--44g/L-hr (based on reactor volume), the average yield was 0.45 g ethanol/g starch, the biocatalyst retained physical integrity and contamination did not affect fermentation. For the Z. mobilis system the maximum volumetric productivity was 38 g ethanol/L-h, the average yield was 0.51 g ethanol/g starch and the FBR was successfully operated for almost one month. In order to develop, scale-up and economically evaluate this system more efficiently, a predictive mathematical model that is based on fundamental principles was developed and verified. This model includes kinetics of reactions, transport phenomena of the reactant and product by diffusion within the biocatalyst bead, and the hydrodynamics of the three phase fluidized bed. The co-immobilized biocatalyst involves a consecutive reaction mechanism The mathematical descriptions of the effectiveness factors of reactant and the intermediate product were developed. Hydrodynamic literature correlations were used to develop the dispersion coefficient and gas, liquid, and solid holdup. The solutions of coupled non-linear second order equations for biocatalyst bead and reactor together with the boundary conditions were solved numerically. This model gives considerable information about the system, such as concentration profiles inside both the beads and column, flow rate and feed concentration influences on productivity and phase hold up, and the influence of enzyme and cell mass loading in the catalyst. This model is generic in nature such that it can be easily applied to a diverse set of applications and operating conditions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yung, M. M.; Cheah, S.; Kuhn, J. N.

The production of biofuels can proceed via a biomass gasification to produce syngas, which can then undergo catalytic conditioning and reforming reactions prior to being sent to a fuel synthesis reactor. Catalysts used for biomass conditioning are plagued by short lifetimes which are a result of, among other things, poisoning. Syngas produced from biomass gasification may contain between 30-300 ppm H2S, depending on the feedstock and gasification conditions, and H2S is a key catalyst poison. In order to overcome catalyst poisoning, either an H2S-tolerant catalyst or an efficient regeneration protocol should be employed. In this study, sulfur K-edge X-ray absorptionmore » near edge spectroscopy (XANES) was used to monitor sulfur species on spent catalyst samples and the transformation of these species from sulfides to sulfates during steam and air regeneration on a Ni/Mg/K/Al2O3 catalyst used to condition biomass-derived syngas. Additionally, nickel K-edge EXAFS and XANES are used to examine the state of nickel species on the catalysts. Post-reaction samples showed the presence of sulfides on the H2S-poisoned nickel catalyst and although some gaseous sulfur species were observed to leave the catalyst bed during regeneration, sulfur remained on the catalyst and a transformation from sulfides to sulfates was observed. The subsequent H2 reduction led to a partial reduction of sulfates back to sulfides. A proposed reaction sequence is presented and recommended regeneration strategies are discussed.« less

DEFE0023863 Final Report, Technology for GHG Emission Reduction and CostCompetitive MilSpec Jet Fuel Production using CTL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hartvigsen, Joseph J; Dimick, Paul; Laumb, Jason D

Ceramatec Inc, in collaboration with IntraMicron (IM), the Energy & Environmental Research Center (EERC) and Sustainable Energy Solutions, LLC (SES), have completed a three-year research project integrating their respective proprietary technologies in key areas to demonstrate production of a jet fuel from coal and biomass sources. The project goals and objectives were to demonstrate technology capable of producing a “commercially-viable quantity” of jet fuel and make significant progress toward compliance with Section 526 of the Energy Independence and Security Act of 2007 (EISA 2007 §526) lifecycle greenhouse gas (GHG) emissions requirements. The Ceramatec led team completed the demonstration of nominalmore » 2 bbl/day Fischer-Tropsch (FT) synthesis pilot plant design, capable of producing a nominal 1 bbl/day in the Jet-A/JP-8 fraction. This production rate would have a capacity of 1,000 gallons of jet fuel per month and provide the design basis of a 100 bbl/day module producing over 2,000 gallons of jet fuel per day. Co-gasification of coal-biomass blends enables a reduction of lifecycle greenhouse gas emissions from equivalent conventional petroleum derived fuel basis. Due to limits of biomass availability within an economic transportation range, implementation of a significant biomass feed fraction will require smaller plants than current world scale CTL and GTL FT plants. Hence a down-scaleable design is essential. The pilot plant design leverages Intramicron’s MicroFiber Entrapped Catalyst (MFEC) support which increases the catalyst bed thermal conductivity two orders of magnitude, allowing thermal management of the FT reaction exotherm in much larger reactor tubes. In this project, single tube reactors having 4.5 inch outer diameter and multi-tube reactors having 4 inch outer diameters were operated, with productivities as high as 1.5 gallons per day per linear foot of reactor tube. A significant reduction in tube count results from the use of large diameter reactor tubes, with an associated reduction in reactor cost. The pilot plant was designed with provisions for product collection capable of operating with conventional wax producing FT catalysts but was operated with a Chevron hybrid wax-free FT catalyst. Process simplification enabled by elimination of the wax hydrocracking process unit provides economic advantages in scaling to biomass capable plant sizes. Intramicron also provided a sulfur capture system based on their Oxidative Sulfur Removal (OSR) catalyst process. The integrated sulfur removal and FT systems were operated with syngas produced by the Transport Reactor Development Unit (TRDU) gasifier at the University of North Dakota EERC. SES performed modeling of their cryogenic carbon capture process on the energy, cost and CO2 emissions impact of the Coal-biomass synthetic fuel process.« less

Experimental Studies of Coal and Biomass Fuel Synthesis and Flame Characterization for Aircraft Engines

DTIC Science & Technology

2010-05-31

near the catalyst bed was about 600 °C. The rest of the reactor, tar/char collector , and transfer hose to the entrance of the condenser were heated to...such as solar and nuclear [2.2-2.3], to reduce carbon dioxide concentrations and to provide heat for the reactions. Carbon dioxide emission may be...assembly Page 27 of 50 AFOSR Grant #FA9 5 5 0-08-1-04 5 6 Final Performance Report Purdue University Ash collector ( pipe end cap) with product aas

Catalytic oxidation for treatment of ECLSS and PMMS waste streams

NASA Technical Reports Server (NTRS)

Akse, James R.; Jolly, Clifford D.

1991-01-01

It is shown that catalytic oxidation is an effective technique for the removal of trace organic contaminants in a multifiltration potable processor's effluent. Essential elements of this technology are devices that deliver oxygen to the influent, and remove gaseous reaction byproducts from the effluent, via hollow-tube, gas-permeable membranes. Iodine, which poisons existing catalysis, is removed by a small deiodination bed prior to catalytic reactor entrance. The catalyst used is a mixture of Pt and Ru deposited on carbon, operating at 125-160 C and 39-90 psi pressures.

Catalytic pyrolysis of model compounds and waste cooking oil for production of light olefins over La/ZSM-5 catalysts

NASA Astrophysics Data System (ADS)

Li, F. W.; Ding, S. L.; Li, L.; Gao, C.; Zhong, Z.; Wang, S. X.; Li, Z. X.

2016-08-01

Waste cooking oil (WCO) and its model compounds (oleic acid and methyl laurate) are catalytically pyrolyzed in a fixed-bed reactor over La modified ZSM-5 catalysts (La/ZSM-5) aiming for production of C2-C4 light olefins. The LaO content in catalysts was set at 0, 2, 6, 10 and 14 wt%. The gas and liquid products are analyzed. The La/ZSM-5 catalyst with 6% LaO showed higher selectivity to light olefins when WCO and methyl laurate were pyrolyzed, and olefin content was 26% for WCO and 21% for methyl laurate. The catalyst with 10% LaO showed high selectivity to light olefins (28.5%) when oleic acid was pyrolyzed. The liquid products from WCO and model compounds mainly contain esters and aromatic hydrocarbons. More esters were observed in liquid products from methyl laurate and WCO pyrolysis, indicating that it is more difficult to pyrolyze esters and WCO than oleic acid. The coked catalysts were analyzed by temperature-programmed oxidation. The result shows that graphite is the main component of coke. The conversion of WCO to light olefins potentially provides an alternative and sustainable route for production of the key petrochemicals.

Partial oxidation of dimethyl ether using the structured catalyst Rh/Al2O3/Al prepared through the anodic oxidation of aluminum.

PubMed

Yu, B Y; Lee, K H; Kim, K; Byun, D J; Ha, H P; Byun, J Y

2011-07-01

The partial oxidation of dimethyl ether (DME) was investigated using the structured catalyst Rh/Al2O3/Al. The porous Al2O3 layer was synthesized on the aluminum plate through anodic oxidation in an oxalic-acid solution. It was observed that about 20 nm nanopores were well developed in the Al2O3 layer. The thickness of Al2O3 layer can be adjusted by controlling the anodizing time and current density. After pore-widening and hot-water treatment, the Al2O3/Al plate was calcined at 500 degrees C for 3 h. The obtained delta-Al2O3 had a specific surface area of 160 m2/g, making it fit to be used as a catalyst support. A microchannel reactor was designed and fabricated to evaluate the catalytic activity of Rh/Al2O3/Al in the partial oxidation of DME. The structured catalyst showed an 86% maximum hydrogen yield at 450 degrees C. On the other hand, the maximum syngas yield by a pack-bed-type catalyst could be attained by using a more than fivefold Rh amount compared to that used in the structured Rh/Al2O3/Al catalyst.

Investigation of a catalytic gas generator for the Space Shuttle APU. [hydrazine Auxiliary Propulsion Unit

NASA Technical Reports Server (NTRS)

Emmons, D. L.; Huxtable, D. D.; Blevins, D. R.

1974-01-01

An investigation was conducted to establish the capability of a monopropellant hydrazine catalytic gas generator to meet the requirements specified for the Space Shuttle APU. Detailed analytical and experimental studies were conducted on potential problem areas including long-term nitriding effects on materials, design variables affecting catalyst life, vehicle vibration effects, and catalyst oxidation/contamination. A full-scale gas generator, designed to operate at a chamber pressure of 750 psia and a flow rate of 0.36 lbm/sec, was fabricated and subjected to three separate life test series. The objective of the first test series was to demonstrate the capability of the gas generator to successfully complete 20 simulated Space Shuttle missions in steady-state operation. The gas generator was then refurbished and subjected to a second series of tests to demonstrate the pulse-mode capability of the gas generator during 20 simulated missions. The third series of tests was conducted with a refurbished reactor to further demonstrate pulse-mode capability with a modified catalyst bed.

Advances in microreaction technology for portable fuel cell applications: Wall coating of thin catalytic films in microreactors

NASA Astrophysics Data System (ADS)

Bravo Bersano, Jaime Cristian

This research has focused on the need to coat microreactor systems composed of channels in the micron size range of 100 to 1000 mum. The experimental procedures and learning are outlined in terms of slurry and surface preparation requirements which are detailed in the experimental section. This system is motivated and applied to micro methanol steam reformers. Thus, a detailed discussion on the driving motivation is given in the introduction. The low temperatures required for steam-reforming of methanol ˜ 493°K (220°C) make it possible to utilize the reformate as a feed to the fuel cell anode. The group of catalysts that shows the highest activity for methanol steam reforming (SR) at low temperature has composition of CuO/ZnO/Al 2O3, which is also the catalyst used for methanol synthesis. Steam reforming of methanol is a highly endothermic process. Conventional reactor configurations, such as a packed bed reactor, operate in a heat transfer limited mode for this reaction. Using catalyst in packed bed form for portable devices is also not convenient due to high pressure drop and possible channeling of gases in addition to poor heat transfer. A wall-coated catalyst represents a superior geometry since it provides lower pressure drop and ease of manufacturing. Due to their small size, microreactors are especially suited for endothermic reactions whose reactivity depends on the rate of heat input. A brief review on microreaction technology is given with a comprehensive survey for catalyst integration into microreactors for catalytic heterogeneous gas phase reactions. The strength of this research is the model that was developed to coat the interior of micron sized capillaries with coats of CuO/ZnO/Al2O 3 slurries as thick as 25 mum in the dry state. The details of the model are given in terms Taylor's theory and Rayleigh's theory. A model is presented that can predict the coat thickness based on experimental conditions The model combines Taylor's experimental work with Lord Rayleigh's instability theory for annular coatings. The model presented serves as a design tool for microreactor design. The model can also estimate the maximum coat thickness possible for a given system. The results are presented in graphical format in the Microchannel Coating Model chapter.

Highly sensitive silicon microreactor for catalyst testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henriksen, Toke R.; Hansen, Ole; Department of Physics, Danish National Research Foundation's Center for Individual Nanoparticle Functionality

2009-12-15

A novel microfabricated chemical reactor for highly sensitive measurements of catalytic activity and surface kinetics is presented. The reactor is fabricated in a silicon chip and is intended for gas-phase reactions at pressures ranging from 0.1 to 5.0 bar. A high sensitivity is obtained by directing the entire gas flow through the catalyst bed to a mass spectrometer, thus ensuring that nearly all reaction products are present in the analyzed gas flow. Although the device can be employed for testing a wide range of catalysts, the primary aim of the design is to allow characterization of model catalysts which canmore » only be obtained in small quantities. Such measurements are of significant fundamental interest but are challenging because of the low surface areas involved. The relationship between the reaction zone gas flow and the pressure in the reaction zone is investigated experimentally. A corresponding theoretical model is presented, and the gas flow through an on-chip flow-limiting capillary is predicted to be in the intermediate regime. The experimental data for the gas flow are found to be in good agreement with the theoretical model. At typical experimental conditions, the total gas flow through the reaction zone is around 3x10{sup 14} molecules s{sup -1}, corresponding to a gas residence time in the reaction zone of about 11 s. To demonstrate the operation of the microreactor, CO oxidation on low-area platinum thin film circles is employed as a test reaction. Using temperature ramping, it is found that platinum catalysts with areas as small as 15 {mu}m{sup 2} are conveniently characterized with the device.« less

Catalytic thermal decomposition of methane to COx-free hydrogen and carbon nanotubes over MgO supported bimetallic group VIII catalysts

NASA Astrophysics Data System (ADS)

Awadallah, A. E.; Aboul-Enein, A. A.; El-Desouki, D. S.; Aboul-Gheit, A. K.

2014-03-01

Bimetallic Ni-Fe, Ni-Co and Fe-Co supported on MgO catalysts with a total metals content of 50 wt.% were evaluated for decomposition of methane to CO/CO2 free hydrogen and carbon nanomaterials. The catalytic runs were carried out at 700 °C under atmospheric pressure using fixed bed horizontal flow reactor. The materials were characterized by XRD, TEM, Raman spectroscopy, surface analysis and TGA-DTG. The data showed that the bimetallic 25% Fe-25%Co/MgO catalyst exhibited remarkable higher activity and stability up to ˜10 h time-on-stream with respect to H2 production. However, the catalytic activity and durability was greatly declined after incorporating 25%Ni to either 25%Fe or 25%Co/MgO catalysts at all time on stream. The main reason for the catalytic inhibition of Ni containing catalysts is consuming NiO during the formation of rock-salt MgxNi(1-x)O solid solution. However, the almost complete segregation of Fe2O3 and Co3O4 oxides played an important role for the high activity of the Fe-Co based catalyst. TEM images illustrate that the accumulated carbon over all catalysts are multi-walled carbon nanotubes in nature. The TG data showed that a higher yield of MWCNTs was achieved over bimetallic Fe-Co catalyst compared to the Ni-Fe or Ni-Co containing catalysts.

A comparison between the four Geldart groups on the performance of a gas-phase annular fluidized bed photoreactor for volatile organic compound oxidation.

PubMed

Diniz, Leonardo Almeida; Hewer, Thiago Lewis Reis; Matsumoto, Danielle; Teixeira, Antonio Carlos Silva Costa

2018-05-07

Heterogeneous photocatalytic oxidation (PCO) is a widely studied alternative for the elimination of volatile organic compounds (VOC) in air. In this context, research on novel photoreactor arrangements to enhance PCO rates is desired. Annular fluidized bed photoreactors (AFBPR) have yielded prominent results when compared to conventional thin film reactors. However, very few works aimed at optimizing AFBPR operation. In this study, TiO 2 photocalytic agglomerates were synthesized and segregated in specific size distributions to behave as Geldart groups A, B, C, and D fluidization. The TiO 2 agglomerates were characterized by XRD, FTIR spectra, and N 2 adsorption. Photocatalyst performances were compared in a 10-mm gapped AFBPR for degrading the model pollutant methyl-ethyl-ketone (MEK), using a 254-nm radiation source. Geldart group C showed to be inadequate for AFBPR operation due to the short operation range between fluidization and elutriation. In all the cases, photocatalytic reaction rates were superior to sole UV photolysis. Group A and group B demonstrated the highest reaction rates. Considerations based on mass transfer suggested that the reasons were enhanced UV distribution within the bed at lower flow rates and superior catalyst surface area at higher flow rates. Results also revealed that groups A, B, and D perform equally per catalyst area within an AFBPR if the fluidization numbers (FN) are high enough.

Monolithic Hydrogen Peroxide Catalyst Bed Development

NASA Technical Reports Server (NTRS)

Ponzo, J. B.

2003-01-01

With recent increased industry and government interest in rocket grade hydrogen peroxide as a viable propellant, significant effort has been expended to improve on earlier developments. This effort has been predominately centered in improving heterogeneous. typically catalyst beds; and homogeneous catalysts, which are typically solutions of catalytic substances. Heterogeneous catalyst beds have traditionally consisted of compressed wire screens plated with a catalytic substance, usually silver, and were used m many RCS applications (X-1, Mercury, and Centaur for example). Aerojet has devised a heterogeneous catalyst design that is monolithic (single piece), extremely compact, and has pressure drops equal to or less than traditional screen beds. The design consists of a bonded stack of very thin, photoetched metal plates, silver coated. This design leads to a high surface area per unit volume and precise flow area, resulting in high, stable, and repeatable performance. Very high throughputs have been demonstrated with 90% hydrogen peroxide. (0.60 lbm/s/sq in at 1775-175 psia) with no flooding of the catalyst bed. Bed life of over 900 seconds has also been demonstrated at throughputs of 0.60 lbm/s/sq in across varying chamber pressures. The monolithic design also exhibits good starting performance, short break-in periods, and will easily scale to various sizes.

Implementing heterogeneous catalytic dechlorination technology for remediating TCE-contaminated groundwater.

PubMed

Davie, Matthew G; Cheng, Hefa; Hopkins, Gary D; Lebron, Carmen A; Reinhard, Martin

2008-12-01

To transition catalytic reductive dechlorination (CRD) into practice, it is necessary to demonstrate the effectiveness, robustness, and economic competitiveness of CRD-based treatment systems. A CRD system scaled up from previous laboratory studies was tested for remediating groundwater contaminated with 500-1200 microg L(-1) trichloroethylene (TCE) at Edwards Air Force Base (AFB), California. Groundwater was pumped from a treatment well at 2 gal min(-1), amended with hydrogen to 0.35 mg L(-1) and contacted for 2.3 min with 20 kg eggshell-coated Pd on alumina beads (2% Pd by wt) packed in a fixed-bed reactor, and then returned to the aquifer. Operation was continuous for 23 h followed a 1 h regeneration cycle. After regeneration, TCE removal was 99.8% for 4 to 9 h and then declined to 98.3% due to catalyst deactivation. The observed catalyst deactivation was tentatively attributed to formation of sulfidic compounds; modeling of catalyst deactivation kinetics suggests the presence of sulfidic species equivalent to 2-4 mg L(-1) hydrogen sulfide in the reactor water. Over the more than 100 day demonstration period, TCE concentrations in the treated groundwater were reduced by >99% to an average concentration of 4.1 microg L(-1). The results demonstrate CRD as a viable treatment alternative technically and economically competitive with activated carbon adsorption and other conventional physicochemical treatmenttechnologies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dayton, David C; Kataria, Atish; Gupta, Rabhubir

The objective of the project is to develop and demonstrate a novel fluidized-bed process module called a Therminator to simultaneously destroy and/or remove tar, NH3 and H2S from raw syngas produced by a fluidized-bed biomass gasifier. The raw syngas contains as much as 10 g/m3 of tar, 4,000 ppmv of NH3 and 100 ppmv of H2S. The goal of the Therminator module would be to use promising regenerable catalysts developed for removing tar, ammonia, and H2S down to low levels (around 10 ppm). Tars are cracked to a non-condensable gas and coke that would deposit on the acid catalyst. Wemore » will deposit coke, much like a fluid catalytic cracker (FCC) in a petroleum refinery. The deposited coke fouls the catalyst, much like FCC, but the coke would be burned off in the regenerator and the regenerated catalyst would be returned to the cracker. The rapid circulation between the cracker and regenerator would ensure the availability of the required amount of regenerated catalyst to accomplish our goal. Also, by removing sulfur down to less than 10 ppmv, NH3 decomposition would also be possible in the cracker at 600-700°C. In the cracker, tar decomposes and lays down coke on the acid sites of the catalyst, NH3 is decomposed using a small amount of metal (e.g., nickel or iron) catalyst incorporated into the catalyst matrix, and H2S is removed by a small amount of a metal oxide (e.g. zinc oxide or zinc titanate) by the H2S-metal oxide reaction to form metal sulfide. After a tolerable decline in activity for these reactions, the catalyst particles (and additives) are transported to the regenerator where they are exposed to air to remove the coke and to regenerate the metal sulfide back to metal oxide. Sulfate formation is avoided by running the regeneration with slightly sub-stoichiometric quantity of oxygen. Following regeneration, the catalyst is transported back to the cracker and the cycling continues. Analogous to an FCC reactor system, rapid cycling will allow the use of very active cracking catalysts that lose activity due to coking within the order of several seconds.« less

Hydrogel coated monoliths for enzymatic hydrolysis of penicillin G

PubMed Central

Smeltink, M. W.; Straathof, A. J. J.; Paasman, M. A.; van de Sandt, E. J. A. X.; Kapteijn, F.; Moulijn, J. A.

2008-01-01

The objective of this work was to develop a hydrogel-coated monolith for the entrapment of penicillin G acylase (E. coli, PGA). After screening of different hydrogels, chitosan was chosen as the carrier material for the preparation of monolithic biocatalysts. This protocol leads to active immobilized biocatalysts for the enzymatic hydrolysis of penicillin G (PenG). The monolithic biocatalyst was tested in a monolith loop reactor (MLR) and compared with conventional reactor systems using free PGA, and a commercially available immobilized PGA. The optimal immobilization protocol was found to be 5 g l−1 PGA, 1% chitosan, 1.1% glutaraldehyde and pH 7. Final PGA loading on glass plates was 29 mg ml−1 gel. For 400 cpsi monoliths, the final PGA loading on functionalized monoliths was 36 mg ml−1 gel. The observed volumetric reaction rate in the MLR was 0.79 mol s−1 m−3monolith. Apart from an initial drop in activity due to wash out of PGA at higher ionic strength, no decrease in activity was observed after five subsequent activity test runs. The storage stability of the biocatalysts is at least a month without loss of activity. Although the monolithic biocatalyst as used in the MLR is still outperformed by the current industrial catalyst (immobilized preparation of PGA, 4.5 mol s−1 m−3catalyst), the rate per gel volume is slightly higher for monolithic catalysts. Good activity and improved mechanical strength make the monolithic bioreactor an interesting alternative that deserves further investigation for this application. Although moderate internal diffusion limitations have been observed inside the gel beads and in the gel layer on the monolith channel, this is not the main reason for the large differences in reactor performance that were observed. The pH drop over the reactor as a result of the chosen method for pH control results in a decreased performance of both the MLR and the packed bed reactor compared to the batch system. A different reactor configuration including an optimal pH profile is required to increase the reactor performance. The monolithic stirrer reactor would be an interesting alternative to improve the performance of the monolith-PGA combination. PMID:18427849

DEVELOPMENT OF ATTRITION RESISTANT IRON-BASED FISCHER-TROPSCH CATALYSTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adeyinka A. Adeyiga

2003-12-01

Fischer-Tropsch (FT) synthesis to convert syngas (CO + H{sub 2}) derived from natural gas or coal to liquid fuels and wax is a well-established technology. For low H{sub 2} to CO ratio syngas produced from CO{sub 2} reforming of natural gas or from gasification of coal, the use of Fe catalysts is attractive because of their high water gas shift activity in addition to their high FT activity. Fe catalysts are also attractive due to their low cost and low methane selectivity. Because of the highly exothermic nature of the FT reaction, there has been a recent move away frommore » fixed-bed reactors toward the development of slurry bubble column reactors (SBCRs) that employ 30 to 90 {micro}m catalyst particles suspended in a waxy liquid for efficient heat removal. However, the use of Fe FT catalysts in an SBCR has been problematic due to severe catalyst attrition resulting in fines that plug the filter employed to separate the catalyst from the waxy product. Fe catalysts can undergo attrition in SBCRs not only due to vigorous movement and collisions but also due to phase changes that occur during activation and reaction. The objectives of this research were to develop a better understanding of the parameters affecting attrition of Fe F-T catalysts suitable for use in SBCRs and to incorporate this understanding into the design of novel Fe catalysts having superior attrition resistance. The catalysts were prepared by co-precipitation, followed by binder addition and spray drying at 250 C in a 1 m diameter, 2 m tall spray dryer. The binder silica content was varied from 0 to 20 wt %. The results show that use of small amounts of precipitated SiO{sub 2} alone in spray-dried Fe catalysts can result in good attrition resistance. All catalysts investigated with SiO{sub 2} wt% {le} 12 produced fines less than 10 wt% during the jet cup attrition test, making them suitable for long-term use in a slurry bubble column reactor. Thus, concentration rather than type of SiO{sub 2} incorporated into catalyst has a more critical impact on catalyst attrition resistance of spray-dried Fe catalysts. Lower amounts of SiO{sub 2} added to a catalyst give higher particle densities and therefore higher attrition resistances. In order to produce a suitable SBCR catalyst, however, the amount of SiO{sub 2} added has to be optimized to provide adequate surface area, particle density, and attrition resistance. Two of the catalysts with precipitated and binder silica were tested in Texas A&M University's CSTR (Autoclave Engineers). Spray-dried catalysts with compositions 100 Fe/5 Cu/4.2 K/11 (P) SiO{sub 2} and 100 Fe/5 Cu/4.2 K/1.1 (B) SiO{sub 2} have excellent selectivity characteristics (low methane and high C{sub 5}{sup +} yields), but their productivity and stability (deactivation rate) need to be improved. Mechanical integrity (attrition strength) of these two catalysts was markedly dependent upon their morphological features. The attrition strength of the catalyst made out of largely spherical particles (1.1 (B) SiO{sub 2}) was considerably higher than that of the catalyst consisting of irregularly shaped particles (11 (P) SiO{sub 2}).« less

Transetherification method

DOEpatents

Hearn, D.

1985-04-09

Transetherification is carried out in a catalytic distillation reactor, wherein the catalytic structure also serves as a distillation structure, by feeding a first ether to the catalyst bed to at least partially dissociate it into a first olefin and a first alcohol while concurrently therewith feeding either a second olefin (preferably a tertiary olefin) having a higher boiling point than said first olefin or a second alcohol having a higher boiling point than said first alcohol to the catalyst whereby either the second olefin and the first alcohol or the first olefin and the second alcohol react to form a second ether which has a higher boiling point than the first ether, which second ether is concurrently removed as a bottoms in the concurrent reaction-distillation to force that reaction to completion, while the unreacted first olefin or first alcohol is removed in the overhead. 1 fig.

Transetherification method

DOEpatents

Hearn, Dennis

1985-01-01

Transetherification is carried out in a catalytic distillation reactor, wherein the catalytic structure also serves as a distillation structure, by feeding a first ether to the catalyst bed to at least partially dissociate it into a first olefin and a first alcohol while concurrently therewith feeding either a second olefin (preferably a tertiary olefin) having a higher boiling point than said first olefin or a second alcohol having a higher boiling point than said first alcohol to the catalyst whereby either the second olefin and the first alcohol or the first olefin and the second alcohol react to form a second ether which has a higher boiling point than the first ether, which second ether is concurrently removed as a bottoms in the concurrent reaction-distillation to force that reaction to completion, while the unreacted first olefin or first alcohol is removed in the overhead.

Six-flow operations for catalyst development in Fischer-Tropsch synthesis: Bridging the gap between high-throughput experimentation and extensive product evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sartipi, Sina, E-mail: S.Sartipi@tudelft.nl, E-mail: J.Gascon@tudelft.nl; Jansma, Harrie; Bosma, Duco

2013-12-15

Design and operation of a “six-flow fixed-bed microreactor” setup for Fischer-Tropsch synthesis (FTS) is described. The unit consists of feed and mixing, flow division, reaction, separation, and analysis sections. The reactor system is made of five heating blocks with individual temperature controllers, assuring an identical isothermal zone of at least 10 cm along six fixed-bed microreactor inserts (4 mm inner diameter). Such a lab-scale setup allows running six experiments in parallel, under equal feed composition, reaction temperature, and conditions of separation and analysis equipment. It permits separate collection of wax and liquid samples (from each flow line), allowing operation with highmore » productivities of C5+ hydrocarbons. The latter is crucial for a complete understanding of FTS product compositions and will represent an advantage over high-throughput setups with more than ten flows where such instrumental considerations lead to elevated equipment volume, cost, and operation complexity. The identical performance (of the six flows) under similar reaction conditions was assured by testing a same catalyst batch, loaded in all microreactors.« less

Pyrolysis of waste tyres: a review.

PubMed

Williams, Paul T

2013-08-01

Approximately 1.5 billion tyres are produced each year which will eventually enter the waste stream representing a major potential waste and environmental problem. However, there is growing interest in pyrolysis as a technology to treat tyres to produce valuable oil, char and gas products. The most common reactors used are fixed-bed (batch), screw kiln, rotary kiln, vacuum and fluidised-bed. The key influence on the product yield, and gas and oil composition, is the type of reactor used which in turn determines the temperature and heating rate. Tyre pyrolysis oil is chemically very complex containing aliphatic, aromatic, hetero-atom and polar fractions. The fuel characteristics of the tyre oil shows that it is similar to a gas oil or light fuel oil and has been successfully combusted in test furnaces and engines. The main gases produced from the pyrolysis of waste tyres are H(2), C(1)-C(4) hydrocarbons, CO(2), CO and H(2)S. Upgrading tyre pyrolysis products to high value products has concentrated on char upgrading to higher quality carbon black and to activated carbon. The use of catalysts to upgrade the oil to a aromatic-rich chemical feedstock or the production of hydrogen from waste tyres has also been reported. Examples of commercial and semi-commercial scale tyre pyrolysis systems show that small scale batch reactors and continuous rotary kiln reactors have been developed to commercial scale. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fluidized-bed catalytic coal-gasification process. [US patent; pretreatment to minimize agglomeration

DOEpatents

Euker, C.A. Jr.; Wesselhoft, R.D.; Dunkleman, J.J.; Aquino, D.C.; Gouker, T.R.

1981-09-14

Coal or similar carbonaceous solids impregnated with gasification catalyst constituents are oxidized by contact with a gas containing between 2 vol % and 21 vol % oxygen at a temperature between 50 and 250/sup 0/C in an oxidation zone and the resultant oxidized, catalyst impregnated solids are then gasified in a fluidized bed gasification zone at an elevated pressure. The oxidation of the catalyst impregnated solids under these conditions insures that the bed density in the fluidized bed gasification zone will be relatively high even though the solids are gasified at elevated pressure and temperature.

Performance Characterization of a Prototype Ultra-Short Channel Monolith Catalytic Reactor for Air Quality Control Applications

NASA Technical Reports Server (NTRS)

Perry, J. L.; Tomes, K. M.; Roychoudhury, S.; Tatara, J. D.

2005-01-01

Contaminated air and process gases, whether in a crewed spacecraft cabin atmosphere, the working volume of a microgravity science or ground-based laboratory experiment facility, or the exhaust from an automobile, are pervasive problems that ultimately effect human health, performance, and well-being. The need for highly-effective, economical decontamination processes spans a wide range of terrestrial and space flight applications. Adsorption processes are used widely for process gas decontamination. Most industrial packed bed adsorption processes use activated carbon because it is cheap and highly effective. Once saturated, however, the adsorbent is a concentrated source of contaminants. Industrial applications either dump or regenerate the activated carbon. Regeneration may be accomplished in-situ or at an off-site location. In either case, concentrated contaminated waste streams must be handled appropriately to minimize environmental impact. As economic and regulatory forces drive toward minimizing waste and environmental impact, thermal catalytic oxidation is becoming more attractive. Through novel reactor and catalyst design, more complete contaminant destruction and greater resistance to poisoning can achieved leading to less waste handling, process down-time, and maintenance. Performance of a prototype thermal catalytic reactor, based on ultra-short channel monolith (USCM) catalyst substrate design, under a variety of process flow and contaminant loading conditions is discussed. The experimental results are evaluated against present and future air quality control and process gas purification processes used on board crewed spacecraft.

Moving bed reactor setup to study complex gas-solid reactions.

PubMed

Gupta, Puneet; Velazquez-Vargas, Luis G; Valentine, Charles; Fan, Liang-Shih

2007-08-01

A moving bed scale reactor setup for studying complex gas-solid reactions has been designed in order to obtain kinetic data for scale-up purpose. In this bench scale reactor setup, gas and solid reactants can be contacted in a cocurrent and countercurrent manner at high temperatures. Gas and solid sampling can be performed through the reactor bed with their composition profiles determined at steady state. The reactor setup can be used to evaluate and corroborate model parameters accounting for intrinsic reaction rates in both simple and complex gas-solid reaction systems. The moving bed design allows experimentation over a variety of gas and solid compositions in a single experiment unlike differential bed reactors where the gas composition is usually fixed. The data obtained from the reactor can also be used for direct scale-up of designs for moving bed reactors.

Synthesis-Structure-Activity Relationships in Co3O4 Catalyzed CO Oxidation

NASA Astrophysics Data System (ADS)

Mingle, Kathleen; Lauterbach, Jochen

2018-05-01

In this work, a statistical design and analysis platform was used to develop cobalt oxide based oxidation catalysts prepared via one pot metal salt reduction. An emphasis was placed upon understanding the effects of synthesis conditions, such as heating regimen and Co2+ concentration on the metal salt reduction mechanism, the resultant nanomaterial properties (i.e. size, crystal structure, and crystal faceting), and the catalytic activity in CO oxidation. This was accomplished by carrying out XRD, TEM, and FTIR studies on synthesis intermediates and products. Additionally, high-throughput experimentation was employed to study the performance of Co3O4 oxidation catalysts over a wide range of reaction conditions using a 16-channel fixed bed reactor equipped with a parallel infrared imaging system. Specifically, Co3O4 nanomaterials of varying properties were evaluated for their performance as CO oxidation catalysts. Figure-of-merits including light-off temperatures and activation energies were measured and mapped back to the catalyst properties and synthesis conditions. Statistical analysis methods were used to elucidate significant property-activity relationships as well as the design rules relevant in the synthesis of active catalysts. It was found that CO oxidation light off temperatures could be decreased to <90°C by utilizing the discovered synthesis-structure-activity relationships.

Multiple use of waste catalysts with and without regeneration for waste polymer cracking.

PubMed

Salmiaton, A; Garforth, A A

2011-06-01

Waste plastics contain a substantial number of valuable chemicals. The wastes from post-consumer as well as from industrial production can be recycled to valuable chemical feedstock, which can be used in refineries and/or petrochemical industries. This chemical recycling process is an ideal approach in recycling the waste for a better environment. Polymer cracking using a laboratory fluidized bed reactor concentrated on the used highly contaminated catalyst, E-Cat 2. Even though E-Cat 2 had low activity due to fewer acid sites, the products yielded were similar with amorphous ASA and were far better than thermal cracking. The high levels of heavy metals, namely nickel and vanadium, deposited during their lifetime as an FCC catalyst, did not greatly affect on the catalyst activity. It was also shown that E-Cat 2 could be used with and without regeneration. Although there was more deactivation when there was no regeneration step, the yield of gases (C(2)-C(7)) remained fairly constant. For the first time, these results indicate that "waste" FCC catalyst (E-Cat) is a good candidate for future feedstock recycling of polymer waste. The major benefits of using E-Cat are a low market price, the ability to tolerate reuse and regeneration capacity. Copyright © 2011 Elsevier Ltd. All rights reserved.

Conversion and Estrogenicity of 17β-estradiol During Photolytic/Photocatalytic Oxidation and Catalytic Wet-air Oxidation.

PubMed

Bistan, Mirjana; Tišler, Tatjana; Pintar, Albin

2012-06-01

Estrogen 17β-estradiol (E2), produced by human body and excreted into municipal wastewaters, belongs to the group of endocrine disrupting compounds that are resistant to biological degradation. The aim of this study was to assess the efficiency of E2 removal from aqueous solutions by means of catalytic wet-air oxidation (CWAO) and photolytic/photocatalytic oxidation. CWAO experiments were conducted in a trickle-bed reactor at temperatures up to 230 °C and oxygen partial pressure of 10 bar over TiO2 and Ru/TiO2 solids. Photolytic/photocatalytic oxidation was carried out in a batch slurry reactor employing a TiO2 P-25 (Degussa) catalyst under visible or UV light. HPLC analysis and yeast estrogen screen assay were used to evaluate the removal of E2 and estrogenicity of treated samples. The latter was completely removed during photolytic/photocatalytic oxidation under UV (365 nm) light and photocatalytic oxidation under visible light. In CWAO experiments, complete removal of both E2 and estrogenicity from the feed solution were noticed in the presence of TiO2 and Ru/TiO2 catalysts.

Study of the Influence of Key Process Parameters on Furfural Production.

PubMed

Fele Žilnik, Ljudmila; Grilc, Viktor; Mirt, Ivan; Cerovečki, Željko

2016-01-01

The present work reports the influence of key process variables on the furfural formation from leached chestnut-wood chips in a pressurized reactor. Effect of temperature, pressure, type and concentration of the catalyst solution, the steam flow rate or stripping module, the moisture content of the wood particles and geometric characteristics such as size and type of the reactor, particle size and bed height were considered systematically. One stage process was only taken into consideration. Lab-scale and pilot-scale studies were performed. The results of the non-catalysed laboratory experiments were compared with an actual non-catalysed (auto-catalysed) industrial process and with experiments on the pilot scale, the latter with 28% higher furfural yield compared to the others. Application of sulphuric acid as catalyst, in an amount of 0.03-0.05 g (H2SO4 100%)/g d.m. (dry material), enables a higher production of furfural at lower temperature and pressure of steam in a shorter reaction time. Pilot scale catalysed experiments have revealed very good performance for furfural formation under less severe operating conditions, with a maximum furfural yield as much as 88% of the theoretical value.

A study on pyrolysis of Canada thistle (Cirsium arvense) with titania based catalysts for bio-fuel production.

PubMed

Aysu, Tevfik

2016-11-01

The catalytic pyrolysis of Cirsium arvense was performed with titania supported catalysts under the operating conditions of 500°C, 40°C/min heating rate, 100mL/min N2 flow rate in a fixed bed reactor for biofuel production. The effect of catalysts on product yields was investigated. The amount of pyrolysis products (bio-char, bio-oil, gas) and the composition of the produced bio-oils were determined by proton nuclear magnetic resonance ((1)H NMR), Fourier transform infrared spectroscopy (FT-IR), gas chromatography/mass spectrometry (GC-MS) and elemental analysis (EA) techniques. Thistle bio-oils had lower O/C and H/C molar ratios compared to feedstock. The highest bio-char and bio-oil yields of 29.32wt% and 36.71wt% were obtained in the presence of Ce/TiO2 and Ni/TiO2 catalysts respectively. GC-MS identified 97 different compounds in the bio-oils obtained from thistle pyrolysis. (1)H NMR analysis showed that the bio-oils contained ∼55-77% aliphatic and ∼6-19% aromatic structural units. Copyright © 2016 Elsevier Ltd. All rights reserved.

Steam reforming of n-hexane on pellet and monolithic catalyst beds. A comparative study on improvements due to heat transfer

NASA Technical Reports Server (NTRS)

1981-01-01

Monolithic catalysts with higher available active surface areas and better thermal conductivity than conventional pellets beds, making possible the steam reforming of fuels heavier than naphtha, were examined. Performance comparisons were made between conventional pellet beds and honeycomb monolith catalysts using n-hexane as the fuel. Metal-supported monoliths were examined. These offer higher structural stability and higher thermal conductivity than ceramic supports. Data from two metal monoliths of different nickel catalyst loadings were compared to pellets under the same operating conditions. Improved heat transfer and better conversion efficiencies were obtained with the monolith having higher catalyst loading. Surface-gas interaction was observed throughout the length of the monoliths.

Solar photolysis of water

NASA Technical Reports Server (NTRS)

Ryason, P. R. (Inventor)

1977-01-01

Hydrogen is produced by the solar photolysis of water in a first photooxidation vessel with a transparent wall in the presence of a water soluble photooxidizable reagent and an insoluble hydrogen recombination catalyst. Simultaneously oxygen is produced in a second photoreduction reactor with a transparent wall in the presence of an insoluble photoreduction reagent catalyst. When spent, the solution from the first reactor is fed into the second reactor. A reaction occurs in the dark in which the redox reagents are regenerated, and the regenerated photooxidation reagent solution is recycled to the first reactor. The photoreduction-catalyst is a bifunctional reagent catalyst including a transition metal salt together with a hydroxyl or chlorohydroxyl decomposition catalyst of high area.

High aspect ratio catalytic reactor and catalyst inserts therefor

DOEpatents

Lin, Jiefeng; Kelly, Sean M.

2018-04-10

The present invention relates to high efficient tubular catalytic steam reforming reactor configured from about 0.2 inch to about 2 inch inside diameter high temperature metal alloy tube or pipe and loaded with a plurality of rolled catalyst inserts comprising metallic monoliths. The catalyst insert substrate is formed from a single metal foil without a central supporting structure in the form of a spiral monolith. The single metal foil is treated to have 3-dimensional surface features that provide mechanical support and establish open gas channels between each of the rolled layers. This unique geometry accelerates gas mixing and heat transfer and provides a high catalytic active surface area. The small diameter, high aspect ratio tubular catalytic steam reforming reactors loaded with rolled catalyst inserts can be arranged in a multi-pass non-vertical parallel configuration thermally coupled with a heat source to carry out steam reforming of hydrocarbon-containing feeds. The rolled catalyst inserts are self-supported on the reactor wall and enable efficient heat transfer from the reactor wall to the reactor interior, and lower pressure drop than known particulate catalysts. The heat source can be oxygen transport membrane reactors.

Evaluation of a hybrid ion exchange-catalyst treatment technology for nitrate removal from drinking water.

PubMed

Bergquist, Allison M; Choe, Jong Kwon; Strathmann, Timothy J; Werth, Charles J

2016-06-01

Ion exchange (IX) is the most common approach to treating nitrate-contaminated drinking water sources, but the cost of salt to make regeneration brine, as well as the cost and environmental burden of waste brine disposal, are major disadvantages. A hybrid ion exchange-catalyst treatment system, in which waste brine is catalytically treated for reuse, shows promise for reducing costs and environmental burdens of the conventional IX system. An IX model with separate treatment and regeneration cycles was developed, and ion selectivity coefficients for each cycle were separately calibrated by fitting experimental data. Of note, selectivity coefficients for the regeneration cycle required fitting the second treatment cycle after incomplete resin regeneration. The calibrated and validated model was used to simulate many cycles of treatment and regeneration using the hybrid system. Simulated waste brines and a real brine obtained from a California utility were also evaluated for catalytic nitrate treatment in a packed-bed, flow-through column with 0.5 wt%Pd-0.05 wt%In/activated carbon support (PdIn/AC). Consistent nitrate removal and no apparent catalyst deactivation were observed over 23 d (synthetic brine) and 45 d (real waste brine) of continuous-flow treatment. Ion exchange and catalyst results were used to evaluate treatment of 1 billion gallons of nitrate-contaminated source water at a 0.5 MGD water treatment plant. Switching from a conventional IX system with a two bed volume regeneration to a hybrid system with the same regeneration length and sequencing batch catalytic reactor treatment would save 76% in salt cost. The results suggest the hybrid system has the potential to address the disadvantages of a conventional IX treatment systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

H-Coal process and plant design

DOEpatents

Kydd, Paul H.; Chervenak, Michael C.; DeVaux, George R.

1983-01-01

A process for converting coal and other hydrocarbonaceous materials into useful and more valuable liquid products. The process comprises: feeding coal and/or other hydrocarbonaceous materials with a hydrogen-containing gas into an ebullated catalyst bed reactor; passing the reaction products from the reactor to a hot separator where the vaporous and distillate products are separated from the residuals; introducing the vaporous and distillate products from the separator directly into a hydrotreater where they are further hydrogenated; passing the residuals from the separator successively through flash vessels at reduced pressures where distillates are flashed off and combined with the vaporous and distillate products to be hydrogenated; transferring the unseparated residuals to a solids concentrating and removal means to remove a substantial portion of solids therefrom and recycling the remaining residual oil to the reactor; and passing the hydrogenated vaporous and distillate products to an atmospheric fractionator where the combined products are fractionated into separate valuable liquid products. The hydrogen-containing gas is generated from sources within the process.

Catalytic Hydrogenation of Bio-Oil for Chemicals and Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, Douglas C.

2006-02-14

The scope of work includes optimizing processing conditions and demonstrating catalyst lifetime for catalyst formulations that are readily scaleable to commercial operations. We use a bench-scale, continuous-flow, packed-bed, catalytic, tubular reactor, which can be operated in the range of 100-400 mL/hr., from 50-400 C and up to 20MPa (see Figure 1). With this unit we produce upgraded bio-oil from whole bio-oil or useful bio-oil fractions, specifically pyrolytic lignin. The product oils are fractionated, for example by distillation, for recovery of chemical product streams. Other products from our tests have been used in further testing in petroleum refining technology at UOPmore » and fractionation for product recovery in our own lab. Further scale-up of the technology is envisioned and we will carry out or support process design efforts with industrial partners, such as UOP.« less

Effects of combustion temperature on PCDD/Fs formation in laboratory-scale fluidized-bed incineration.

PubMed

Hatanaka, T; Imagawa, T; Kitajima, A; Takeuchi, M

2001-12-15

Combustion experiments in a laboratory-scale fluidized-bed reactor were performed to elucidate the effects of combustion temperature on PCDD/Fs formation during incineration of model wastes with poly(vinyl chloride) or sodium chloride as a chlorine source and copper chloride as a catalyst. Each temperature of primary and secondary combustion zones in the reactor was set independently to 700, 800, and 900 degrees C using external electric heaters. The PCDD/Fs concentration is reduced as the temperature of the secondary combustion zone increases. It is effective to keep the temperature of the secondary combustion zone high enough to reduce their release during the waste incineration. On the other hand, as the temperature of the primary combustion zone rises, the PCDD/Fs concentration also increases. Lower temperature of the primary combustion zone results in less PCDD/Fs concentration in these experimental conditions. This result is probably related to the devolatilization rate of the solid waste in the primary combustion zone. The temperature decrease slows the devolatilization rate and promotes mixing of oxygen and volatile matters from the solid waste. This contributes to completing combustion reactions, resulting in reducing the PCDD/Fs concentration.

Recent Advances in Pd-Based Membranes for Membrane Reactors.

PubMed

Arratibel Plazaola, Alba; Pacheco Tanaka, David Alfredo; Van Sint Annaland, Martin; Gallucci, Fausto

2017-01-01

Palladium-based membranes for hydrogen separation have been studied by several research groups during the last 40 years. Much effort has been dedicated to improving the hydrogen flux of these membranes employing different alloys, supports, deposition/production techniques, etc. High flux and cheap membranes, yet stable at different operating conditions are required for their exploitation at industrial scale. The integration of membranes in multifunctional reactors (membrane reactors) poses additional demands on the membranes as interactions at different levels between the catalyst and the membrane surface can occur. Particularly, when employing the membranes in fluidized bed reactors, the selective layer should be resistant to or protected against erosion. In this review we will also describe a novel kind of membranes, the pore-filled type membranes prepared by Pacheco Tanaka and coworkers that represent a possible solution to integrate thin selective membranes into membrane reactors while protecting the selective layer. This work is focused on recent advances on metallic supports, materials used as an intermetallic diffusion layer when metallic supports are used and the most recent advances on Pd-based composite membranes. Particular attention is paid to improvements on sulfur resistance of Pd based membranes, resistance to hydrogen embrittlement and stability at high temperature.

Deleterious Thermal Effects Due To Randomized Flow Paths in Pebble Bed, and Particle Bed Style Reactors

NASA Technical Reports Server (NTRS)

Moran, Robert P.

2013-01-01

A review of literature associated with Pebble Bed and Particle Bed reactor core research has revealed a systemic problem inherent to reactor core concepts which utilize randomized rather than structured coolant channel flow paths. For both the Pebble Bed and Particle Bed Reactor designs; case studies reveal that for indeterminate reasons, regions within the core would suffer from excessive heating leading to thermal runaway and localized fuel melting. A thermal Computational Fluid Dynamics model was utilized to verify that In both the Pebble Bed and Particle Bed Reactor concepts randomized coolant channel pathways combined with localized high temperature regions would work together to resist the flow of coolant diverting it away from where it is needed the most to cooler less resistive pathways where it is needed the least. In other words given the choice via randomized coolant pathways the reactor coolant will take the path of least resistance, and hot zones offer the highest resistance. Having identified the relationship between randomized coolant channel pathways and localized fuel melting it is now safe to assume that other reactor concepts that utilize randomized coolant pathways such as the foam core reactor are also susceptible to this phenomenon.

Too much FCC catalyst activity can cut yields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wichers, W.R.; Upson, L.

1984-03-19

For many people working in the field of catalytic cracking, high equilibrium catalyst activity is inherently good. It is surprising how many times this line of reasoning is accepted by the refiner. There also seems to be something psychologically satisfying in seeing an equilibrium catalyst report where the catalyst activity is reported as a high number. Generally, everyone is happy when the reported activity of equilibrium catalyst is increasing and unhappy when it is going down. In the past, increasing catalyst activity did result in improved operations. For units that operated with substantial amounts of bed cracking, higher activity catalystmore » allowed the amount of bed cracking to be reduced and the relative amount of cracking that occurred in the riser to be increased. The switch from bed to riser cracking decreased catalytic coke make and gasoline overcracking, thus reducing regenerator temperature and improving gasoline yields.« less

Processes and catalysts for conducting fischer-tropsch synthesis in a slurry bubble column reactor

DOEpatents

Singleton, Alan H.; Oukaci, Rachid; Goodwin, James G.

1999-01-01

Processes and catalysts for conducting Fischer-Tropsch synthesis in a slurry bubble column reactor (SBCR). One aspect of the invention involves the use of cobalt catalysts without noble metal promotion in an SBCR. Another aspect involves using palladium promoted cobalt catalysts in an SBCR. Methods for preparing noble metal promoted catalysts via totally aqueous impregnation and procedures for producing attrition resistant catalysts are also provided.

Catalytic dry reforming of waste plastics from different waste treatment plants for production of synthesis gases.

PubMed

Saad, Juniza Md; Williams, Paul T

2016-12-01

Catalytic dry reforming of mixed waste plastics, from a range of different municipal, commercial and industrial sources, were processed in a two-stage fixed bed reactor. Pyrolysis of the plastics took place in the first stage and dry (CO 2 ) reforming of the evolved pyrolysis gases took place in the second stage in the presence of Ni/Al 2 O 3 and Ni-Co/Al 2 O 3 catalysts in order to improve the production of syngas from the dry reforming process. The results showed that the highest amount of syngas yield was obtained from the dry reforming of plastic waste from the agricultural industry with the Ni/Al 2 O 3 catalyst, producing 153.67mmol syngas g -1 waste . The addition of cobalt metal as a promoter to the Ni/Al 2 O 3 catalyst did not have a major influence on syngas yield. Overall, the catalytic-dry reforming of waste plastics from various waste treatment plants showed great potential towards the production of synthesis gases. Copyright © 2016 Elsevier Ltd. All rights reserved.

Co-processing CH4 and oxygenates on Mo/H-ZSM-5: 2. CH4-CO2 and CH4-HCOOH mixtures.

PubMed

Bedard, Jeremy; Hong, Do-Young; Bhan, Aditya

2013-08-07

Co-processing of formic acid or carbon dioxide with CH4 (FA/CH4 = 0.01-0.03 and CO2/CH4 = 0.01-0.03) on Mo/H-ZSM-5 catalysts at 950 K with the prospect of kinetically coupling dehydrogenation and deoxygenation cycles results instead in a two-zone, staged bed reactor configuration consisting of upstream oxygenate/CH4 reforming and downstream CH4 dehydroaromatization. The addition of an oxygenate co-feed (oxygenate/CH4 = 0.01-0.03) causes oxidation of the active molybdenum carbide catalyst while producing CO and H2 until completely converted. Forward rates of C6H6 synthesis are unaffected by the introduction of an oxygenate co-feed after rigorously accounting for the thermodynamic reversibility caused by the H2 produced in oxygenate reforming reactions and the fraction of the active catalyst deemed unavailable for CH4 DHA. All effects of co-processing oxygenates with CH4 can be construed in terms of an approach to equilibrium.

The direct liquefaction proof of concept program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Comolli, A.G.; Lee, L.K.; Pradhan, V.R.

1995-12-31

The goal of the Proof of Concept (POC) Program is to develop Direct Coal Liquefaction and associated transitional technologies towards commercial readiness for economically producing premium liquid fuels from coal in an environmentally acceptable manner. The program focuses on developing the two-stage liquefaction (TSL) process by utilizing geographically strategic feedstocks, commercially feasible catalysts, new prototype equipment, and testing co-processing or alternate feedstocks and improved process configurations. Other high priority objectives include dispersed catalyst studies, demonstrating low rank coal liquefaction without solids deposition, improving distillate yields on a unit reactor volume basis, demonstrating ebullated bed operations while obtaining scale-up data, demonstratingmore » optimum catalyst consumption using new concepts (e.g. regeneration, cascading), producing premium products through on-line hydrotreating, demonstrating improved hydrogen utilization for low rank coals using novel heteroatom removal methods, defining and demonstrating two-stage product properties for upgrading; demonstrating efficient and economic solid separation methods, examining the merits of integrated coal cleaning, demonstrating co-processing, studying interactions between the preheater and first and second-stage reactors, improving process operability by testing and incorporating advanced equipment and instrumentation, and demonstrating operation with alternate coal feedstocks. During the past two years major PDU Proof of Concept runs were completed. POC-1 with Illinois No. 6 coal and POC-2 with Black Thunder sub-bituminous coal. Results from these operations are continuing under review and the products are being further refined and upgraded. This paper will update the results from these operations and discuss future plans for the POC program.« less

Method and apparatus for a combination moving bed thermal treatment reactor and moving bed filter

DOEpatents

Badger, Phillip C.; Dunn, Jr., Kenneth J.

2015-09-01

A moving bed gasification/thermal treatment reactor includes a geometry in which moving bed reactor particles serve as both a moving bed filter and a heat carrier to provide thermal energy for thermal treatment reactions, such that the moving bed filter and the heat carrier are one and the same to remove solid particulates or droplets generated by thermal treatment processes or injected into the moving bed filter from other sources.

Hydrocarbon Liquid Production via Catalytic Hydroprocessing of Phenolic Oils Fractionated from Fast Pyrolysis of Red Oak and Corn Stover

DOE PAGES

Elliott, Douglas C.; Wang, Huamin; Rover, Majorie; ...

2015-04-13

Phenolic oils were produced from fast pyrolysis of two different biomass feedstocks, red oak and corn stover and evaluated in hydroprocessing tests for production of liquid hydrocarbon products. The phenolic oils were produced with a bio-oil fractionating process in combination with a simple water wash of the heavy ends from the fractionating process. Phenolic oils derived from the pyrolysis of red oak and corn stover were recovered with yields (wet biomass basis) of 28.7 wt% and 14.9 wt%, respectively, and 54.3% and 58.6% on a carbon basis. Both precious metal catalysts and sulfided base metal catalyst were evaluated for hydrotreatingmore » the phenolic oils, as an extrapolation from whole bio-oil hydrotreatment. They were effective in removing heteroatoms with carbon yields as high as 81% (unadjusted for the 90% carbon balance). There was nearly complete heteroatom removal with residual O of only 0.4% to 5%, while N and S were reduced to less than 0.05%. Use of the precious metal catalysts resulted in more saturated products less completely hydrotreated compared to the sulfided base metal catalyst, which was operated at higher temperature. The liquid product was 42-52% gasoline range molecules and about 43% diesel range molecules. Particulate matter in the phenolic oils complicated operation of the reactors, causing plugging in the fixed-beds especially for the corn stover phenolic oil. This difficulty contrasts with the catalyst bed fouling and plugging, which is typically seen with hydrotreatment of whole bio-oil. This problem was substantially alleviated by filtering the phenolic oils before hydrotreating. More thorough washing of the phenolic oils during their preparation from the heavy ends of bio-oil or on-line filtration of pyrolysis vapors to remove particulate matter before condensation of the bio-oil fractions is recommended.« less

Hydrocarbon Liquid Production via Catalytic Hydroprocessing of Phenolic Oils Fractionated from Fast Pyrolysis of Red Oak and Corn Stover

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, Douglas C.; Wang, Huamin; Rover, Majorie

Phenolic oils were produced from fast pyrolysis of two different biomass feedstocks, red oak and corn stover and evaluated in hydroprocessing tests for production of liquid hydrocarbon products. The phenolic oils were produced with a bio-oil fractionating process in combination with a simple water wash of the heavy ends from the fractionating process. Phenolic oils derived from the pyrolysis of red oak and corn stover were recovered with yields (wet biomass basis) of 28.7 wt% and 14.9 wt%, respectively, and 54.3% and 58.6% on a carbon basis. Both precious metal catalysts and sulfided base metal catalyst were evaluated for hydrotreatingmore » the phenolic oils, as an extrapolation from whole bio-oil hydrotreatment. They were effective in removing heteroatoms with carbon yields as high as 81% (unadjusted for the 90% carbon balance). There was nearly complete heteroatom removal with residual O of only 0.4% to 5%, while N and S were reduced to less than 0.05%. Use of the precious metal catalysts resulted in more saturated products less completely hydrotreated compared to the sulfided base metal catalyst, which was operated at higher temperature. The liquid product was 42-52% gasoline range molecules and about 43% diesel range molecules. Particulate matter in the phenolic oils complicated operation of the reactors, causing plugging in the fixed-beds especially for the corn stover phenolic oil. This difficulty contrasts with the catalyst bed fouling and plugging, which is typically seen with hydrotreatment of whole bio-oil. This problem was substantially alleviated by filtering the phenolic oils before hydrotreating. More thorough washing of the phenolic oils during their preparation from the heavy ends of bio-oil or on-line filtration of pyrolysis vapors to remove particulate matter before condensation of the bio-oil fractions is recommended.« less

Catalyst for coal liquefaction process

DOEpatents

Huibers, Derk T. A.; Kang, Chia-Chen C.

1984-01-01

An improved catalyst for a coal liquefaction process; e.g., the H-Coal Process, for converting coal into liquid fuels, and where the conversion is carried out in an ebullated-catalyst-bed reactor wherein the coal contacts catalyst particles and is converted, in addition to liquid fuels, to gas and residual oil which includes preasphaltenes and asphaltenes. The improvement comprises a catalyst selected from the group consisting of the oxides of nickel molybdenum, cobalt molybdenum, cobalt tungsten, and nickel tungsten on a carrier of alumina, silica, or a combination of alumina and silica. The catalyst has a total pore volume of about 0.500 to about 0.900 cc/g and the pore volume comprises micropores, intermediate pores and macropores, the surface of the intermediate pores being sufficiently large to convert the preasphaltenes to asphaltenes and lighter molecules. The conversion of the asphaltenes takes place on the surface of micropores. The macropores are for metal deposition and to prevent catalyst agglomeration. The micropores have diameters between about 50 and about 200 angstroms (.ANG.) and comprise from about 50 to about 80% of the pore volume, whereas the intermediate pores have diameters between about 200 and 2000 angstroms (.ANG.) and comprise from about 10 to about 25% of the pore volume, and the macropores have diameters between about 2000 and about 10,000 angstroms (.ANG.) and comprise from about 10 to about 25% of the pore volume. The catalysts are further improved where they contain promoters. Such promoters include the oxides of vanadium, tungsten, copper, iron and barium, tin chloride, tin fluoride and rare earth metals.

MTBE Hydrolysis in Dilute Aqueous Solution Using Heterogeneous Strong Acid Catalysts

NASA Astrophysics Data System (ADS)

Rixey, W. G.

2003-12-01

The objective of this research has been the development of a potential in situ catalytic process for the hydrolysis of methyl tertiary butyl ether (MTBE) to tertiary butyl alcohol (TBA) and methanol in ground water. Bench-scale batch reactor studies were conducted over a temperature range of 23 deg C to 50 deg C with several heterogeneous strong acid catalysts to obtain rates of hydrolysis of MTBE to TBA and methanol at dilute concentrations in water. Continuous flow experiments were then conducted to obtain kinetic data over a temperature range of 15 deg C to 50 deg C for various flow rates for the most active catalysts. It was found that the batch and continuous flow experiments yielded similar intrinsic kinetic rate constants when sorption of MTBE to the catalyst was accounted for. Additional fixed-bed experiments were conducted with deionized water and 0.005 M CaCl2 feed solutions containing 100 mg/L MTBE, respectively, to assess the deactivation of the catalyst, and deactivation was found to be controlled by ion exchange of H+ in the catalyst with Ca+2 in the feed. Our results indicate that, for low to moderate groundwater velocities and cation concentrations at ambient temperatures, an in situ reactive barrier process using the most active catalysts studied in this research could be a viable process in terms of both suitable conversion of MTBE and catalyst life. Although application to in situ remediation is emphasized, the results of this research are also applicable to ex-situ groundwater treatment.

Processes and catalysts for conducting Fischer-Tropsch synthesis in a slurry bubble column reactor

DOEpatents

Singleton, A.H.; Oukaci, R.; Goodwin, J.G.

1999-08-17

Processes and catalysts are disclosed for conducting Fischer-Tropsch synthesis in a slurry bubble column reactor (SBCR). One aspect of the invention involves the use of cobalt catalysts without noble metal promotion in an SBCR. Another aspect involves using palladium promoted cobalt catalysts in an SBCR. Methods for preparing noble metal promoted catalysts via totally aqueous impregnation and procedures for producing attrition resistant catalysts are also provided. 1 fig.

Advanced CO2 Removal and Reduction System

NASA Technical Reports Server (NTRS)

Alptekin, Gokhan; Dubovik, Margarita; Copeland, Robert J.

2011-01-01

An advanced system for removing CO2 and H2O from cabin air, reducing the CO2, and returning the resulting O2 to the air is less massive than is a prior system that includes two assemblies . one for removal and one for reduction. Also, in this system, unlike in the prior system, there is no need to compress and temporarily store CO2. In this present system, removal and reduction take place within a single assembly, wherein removal is effected by use of an alkali sorbent and reduction is effected using a supply of H2 and Ru catalyst, by means of the Sabatier reaction, which is CO2 + 4H2 CH4 + O2. The assembly contains two fixed-bed reactors operating in alternation: At first, air is blown through the first bed, which absorbs CO2 and H2O. Once the first bed is saturated with CO2 and H2O, the flow of air is diverted through the second bed and the first bed is regenerated by supplying it with H2 for the Sabatier reaction. Initially, the H2 is heated to provide heat for the regeneration reaction, which is endothermic. In the later stages of regeneration, the Sabatier reaction, which is exothermic, supplies the heat for regeneration.

Hydrogen production from high moisture content biomass in supercritical water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antal, M.J. Jr.; Xu, X.

1998-08-01

By mixing wood sawdust with a corn starch gel, a viscous paste can be produced that is easily delivered to a supercritical flow reactor by means of a cement pump. Mixtures of about 10 wt% wood sawdust with 3.65 wt% starch are employed in this work, which the authors estimate to cost about $0.043 per lb. Significant reductions in feed cost can be achieved by increasing the wood sawdust loading, but such an increase may require a more complex pump. When this feed is rapidly heated in a tubular flow reactor at pressures above the critical pressure of water (22more » MPa), the sawdust paste vaporizes without the formation of char. A packed bed of carbon catalyst in the reactor operating at about 650 C causes the tarry vapors to react with water, producing hydrogen, carbon dioxide, and some methane with a trace of carbon monoxide. The temperature and history of the reactor`s wall influence the hydrogen-methane product equilibrium by catalyzing the methane steam reforming reaction. The water effluent from the reactor is clean. Other biomass feedstocks, such as the waste product of biodiesel production, behave similarly. Unfortunately, sewage sludge does not evidence favorable gasification characteristics and is not a promising feedstock for supercritical water gasification.« less

Catalytic combustion of volatile organic compounds.

PubMed

Everaert, K; Baeyens, J

2004-06-18

Despite the success of adsorption and thermal incineration of (C)VOC emissions, there is still a need for research on techniques which are both economically more favorable and actually destroy the pollutants rather than merely remove them for recycling elsewhere in the biosphere. The catalytic destruction of (C)VOC to CO2, H2O and HCl/Cl2 appears very promising in this context and is the subject of the present paper. The experiments mainly investigate the catalytic combustion of eight target compounds, all of which are commonly encountered in (C)VOC emissions and/or act as precursors for the formation of PCDD/F. Available literature on the different catalysts active in the oxidation of (C)VOC is reviewed and the transition metal oxide complex V2O5-WO3/TiO2 appears most suitable for the current application. Different reactor geometries (e.g. fixed pellet beds, honeycombs, etc.) are also described. In this research a novel catalyst type is introduced, consisting of a V2O5-WO3/TiO2 coated metal fiber fleece. The conversion of (C)VOC by thermo-catalytic reactions is governed by both reaction kinetics and reaction equilibrium. Full conversion of all investigated VOC to CO2, Cl2, HCl and H2O is thermodynamically feasible within the range of experimental conditions used in this work (260-340 degrees C, feed concentrations 30-60 ppm). A first-order rate equation is proposed for the (C)VOC oxidation reactions. The apparent rate constant is a combination of reaction kinetics and mass transfer effects. The oxidation efficiencies were measured with various (C)VOC in the temperature range of 260-340 degrees C. Literature data for oxidation reactions in fixed beds and honeycomb reactors are included in the assessment. Mass transfer resistances are calculated and are generally negligible for fleece reactors and fixed pellet beds, but can be of importance for honeycomb monoliths. The experimental investigations demonstrate: (i) that the conversion of the hydrocarbons is independent of the oxygen concentration, corresponding to a zero-order dependency of the reaction rate; (ii) that the conversion of the hydrocarbons is a first-order reaction in the (C)VOC; (iii) that the oxidation of the (C)VOC proceeds to a higher extent with increasing temperature, with multiple chlorine substitution enhancing the reactivity; (iv) that the reaction rate constant follows an Arrhenius dependency. The reaction rate constant kr (s(-1)) and the activation energy E (kJ/mol) are determined from the experimental results. The activation energy is related to the characteristics of the (C)VOC under scrutiny and correlated in terms of the molecular weight. The kr-values are system-dependent and hence limited in design application to the specific VOC-catalyst combination being studied. To achieve system-independency, kr-values are transformed into an alternative kinetic constant K (m3/(m2u)) expressed per unit of catalyst surface and thus independent of the amount of catalyst present in the reactor. Largely different experimental data can be fitted in terms of this approach. Results are thereafter used to define the Arrhenius pre-exponential factor A*, itself expressed in terms of the activation entropy. Destruction efficiencies for any given reactor set-up can be predicted from E- and A*-correlations. The excellent comparison of predicted and measured destruction efficiencies for a group of chlorinated aromatics stresses the validity of the design approach. Since laboratory-scale experiments using PCDD/F are impossible, pilot and full-scale tests of PCDD/F oxidation undertaken in Flemish MSWIs and obtained from literature are reported. From the data it is clear that: (i) destruction efficiencies are normally excellent; (ii) the efficiencies increase with increasing operating temperature; (iii) the higher degree of chlorination does not markedly affect the destruction efficiency. Finally, all experimental findings are used in design recommendations for the catalytic oxidation of (C)VOC and PCDD/F. Predicted values of the a)VOC and PCDD/F. Predicted values of the acceptable space velocity correspond with the cited industrial values, thus stressing the validity of the design strategy and equations developed in the present paper.

Fluidized bed catalytic pyrolysis of eucalyptus over hzsm-5: effect of acid density and gallium modification on catalyst deactivation

USDA-ARS?s Scientific Manuscript database

Catalytic fast pyrolysis of eucalyptus wood was performed on a continuous laboratory scale fluidized bed fast pyrolysis system. Catalytic activity was monitored from use of fresh catalyst up to a cumulative biomass to catalyst ratio (B/C) of 4/1 over extruded pellets of three different ZSM-5 catalys...

Plasma-catalyst hybrid reactor with CeO2/γ-Al2O3 for benzene decomposition with synergetic effect and nano particle by-product reduction.

PubMed

Mao, Lingai; Chen, Zhizong; Wu, Xinyue; Tang, Xiujuan; Yao, Shuiliang; Zhang, Xuming; Jiang, Boqiong; Han, Jingyi; Wu, Zuliang; Lu, Hao; Nozaki, Tomohiro

2018-04-05

A dielectric barrier discharge (DBD) catalyst hybrid reactor with CeO 2 /γ-Al 2 O 3 catalyst balls was investigated for benzene decomposition at atmospheric pressure and 30 °C. At an energy density of 37-40 J/L, benzene decomposition was as high as 92.5% when using the hybrid reactor with 5.0wt%CeO 2 /γ-Al 2 O 3 ; while it was 10%-20% when using a normal DBD reactor without a catalyst. Benzene decomposition using the hybrid reactor was almost the same as that using an O 3 catalyst reactor with the same CeO 2 /γ-Al 2 O 3 catalyst, indicating that O 3 plays a key role in the benzene decomposition. Fourier transform infrared spectroscopy analysis showed that O 3 adsorption on CeO 2 /γ-Al 2 O 3 promotes the production of adsorbed O 2 - and O 2 2‒ , which contribute benzene decomposition over heterogeneous catalysts. Nano particles as by-products (phenol and 1,4-benzoquinone) from benzene decomposition can be significantly reduced using the CeO 2 /γ-Al 2 O 3 catalyst. H 2 O inhibits benzene decomposition; however, it improves CO 2 selectivity. The deactivated CeO 2 /γ-Al 2 O 3 catalyst can be regenerated by performing discharges at 100 °C and 192-204 J/L. The decomposition mechanism of benzene over CeO 2 /γ-Al 2 O 3 catalyst was proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

Stabilization of Softwood-Derived Pyrolysis Oils for Continuous Bio-oil Hydroprocessing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olarte, Mariefel V.; Zacher, Alan H.; Padmaperuma, Asanga B.

The use of fast pyrolysis as a potential renewable liquid transportation fuel alternative to crude oil depends on successful catalytic upgrading to produce a refinery-ready product with oxygen content and qualities (i.e. specific functional group or compound content) that is compatible with the product’s proposed insertion point. Catalytic upgrading of bio-oil requires high temperature and pressure, while similar to crude oil hydrotreating, is not as straightforward for the thermally unstable pyrolysis oil. For years, a two-temperature zone, downflow trickle bed reactor was the state-of-the art for continuous operation. However, pressure excursion due to plug formation still occurred, typically at themore » high temperature transition zone, leading to a process shutdown within 140 h. Recently, a bio-oil pre-treatment process, together with a robust commercial catalyst, was found to be enabling the continuous operation of the two-zone hydroprocessing system. Here, we report the results on pre-treating bio-oil at 413 K and 8.4 MPa of flowing H2 (500 L H2/L bio-oil, 0.5 L bio-oil/L catalyst bed) and the attempts to characterize this oil product to understand the chemistry which enabled the long-term processing of bio-oil.« less

Packed fluidized bed blanket for fusion reactor

DOEpatents

Chi, John W. H.

1984-01-01

A packed fluidized bed blanket for a fusion reactor providing for efficient radiation absorption for energy recovery, efficient neutron absorption for nuclear transformations, ease of blanket removal, processing and replacement, and on-line fueling/refueling. The blanket of the reactor contains a bed of stationary particles during reactor operation, cooled by a radial flow of coolant. During fueling/refueling, an axial flow is introduced into the bed in stages at various axial locations to fluidize the bed. When desired, the fluidization flow can be used to remove particles from the blanket.

Removal of ammonia solutions used in catalytic wet oxidation processes.

PubMed

Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

2003-08-01

Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

Mechanism of Hg(0) oxidation in the presence of HCl over a commercial V2O5-WO3/TiO2 SCR catalyst.

PubMed

Liu, Ruihui; Xu, Wenqing; Tong, Li; Zhu, Tingyu

2015-10-01

Experiments were conducted in a fixed-bed reactor containing a commercial V2O5/WO3/TiO2 catalyst to investigate mercury oxidation in the presence of HCl and O2. Mercury oxidation was improved significantly in the presence of HCl and O2, and the Hg(0) oxidation efficiencies decreased slowly as the temperature increased from 200 to 400°C. Upon pretreatment with HCl and O2 at 350°C, the catalyst demonstrated higher catalytic activity for Hg(0) oxidation. Notably, the effect of pretreatment with HCl alone was not obvious. For the catalyst treated with HCl and O2, better performance was observed with lower reaction temperatures. The results showed that both HCl and Hg(0) were first adsorbed onto the catalyst and then reacted with O2 following its adsorption, which indicates that the oxidation of Hg(0) over the commercial catalyst followed the Langmuir-Hinshelwood mechanism. Several characterization techniques, including Hg(0) temperature-programmed desorption (Hg-TPD) and X-ray photoelectron spectroscopy (XPS), were employed in this work. Hg-TPD profiles showed that weakly adsorbed mercury species were converted to strongly bound species in the presence of HCl and O2. XPS patterns indicated that new chemisorbed oxygen species were formed by the adsorption of HCl, which consequently facilitated the oxidation of mercury. Copyright © 2015. Published by Elsevier B.V.

Comparative study of activated carbon, natural zeolite, and green sand supports for CuOX and ZnO sites as ozone decomposition catalyst

NASA Astrophysics Data System (ADS)

Azhariyah, A. S.; Pradyasti, A.; Dianty, A. G.; Bismo, S.

2018-03-01

This research was based on ozone decomposition in industrial environment. Ozone is harmful to human. Therefore, catalysts were made as a mask filter to decompose ozone. Comparison studies of catalyst supports were done using Granular Activated Carbon (GAC), Natural Zeolite (NZ), and Green Sand (GS). GAC showed the highest catalytic activity compared to other supports with conversion of 98%. Meanwhile, the conversion using NZ was only 77% and GS had been just 27%. GAC had the highest catalytic activity because it had the largest pore volume, which is 0.478 cm3/g. So GAC was used as catalyst supports. To have a higher conversion in ozone decomposition, GAC was impregnated with metal oxide as the active site of the catalyst. Active site comparison was made using CuOX and ZnO as the active site. Morphology, composition, and crystal phase were analyzed using SEM-EDX, XRF, and XRD methods. Mask filter, which contained catalysts for ozone decomposition, was tested using a fixed bed reactor at room temperature and atmospheric pressure. The result of conversion was analyzed using iodometric method. CuOX/GAC and ZnO/GAC 2%-w showed the highest catalytic activity and conversion reached 100%. From the durability test, CuOX/GAC 2%-w was better than ZnO/GAC 2%-w because the conversion of ozone to oxygen reached 100% with the lowest conversion was 70% for over eight hours.

Nitrogen removal from wastewater by a catalytic oxidation method.

PubMed

Huang, T L; Macinnes, J M; Cliffe, K R

2001-06-01

The ammonia-containing waste produced in industries is usually characterized by high concentration and high temperature, and is not treatable by biological methods directly. In this study, a hydrophobic Pt/SDB catalyst was first used in a trickle-bed reactor to remove ammonia from wastewater. In the reactor, both stripping and catalytic oxidation occur simultaneously. It was found that higher temperature and higher oxygen partial pressure enhanced the ammonia removal. A reaction pathway, which involves oxidizing ammonia to nitric oxide, which then further reacts with ammonia to produce nitrogen and water, was confirmed. Small amounts of by-products, nitrites and nitrates were also detected in the resultant reaction solution. These compounds came from the absorption of nitrogen oxides. Both the minimum NO2- selectivity and maximum ammonia removal were achieved when the resultant pH of treated water was near 7.5 for a feed of unbuffered ammonia solution.

Steam reformer with catalytic combustor

DOEpatents

Voecks, Gerald E.

1990-03-20

A steam reformer is disclosed having an annular steam reforming catalyst bed formed by concentric cylinders and having a catalytic combustor located at the center of the innermost cylinder. Fuel is fed into the interior of the catalytic combustor and air is directed at the top of the combustor, creating a catalytic reaction which provides sufficient heat so as to maintain the catalytic reaction in the steam reforming catalyst bed. Alternatively, air is fed into the interior of the catalytic combustor and a fuel mixture is directed at the top. The catalytic combustor provides enhanced radiant and convective heat transfer to the reformer catalyst bed.

Steam reformer with catalytic combustor

NASA Technical Reports Server (NTRS)

Voecks, Gerald E. (Inventor)

1990-01-01

A steam reformer is disclosed having an annular steam reforming catalyst bed formed by concentric cylinders and having a catalytic combustor located at the center of the innermost cylinder. Fuel is fed into the interior of the catalytic combustor and air is directed at the top of the combustor, creating a catalytic reaction which provides sufficient heat so as to maintain the catalytic reaction in the steam reforming catalyst bed. Alternatively, air is fed into the interior of the catalytic combustor and a fuel mixture is directed at the top. The catalytic combustor provides enhanced radiant and convective heat transfer to the reformer catalyst bed.

Low NO[sub x], cogeneration process and system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bell, R.D.

1993-07-06

A process is described for low NO[sub x] cogeneration to produce electricity and useful heat, which comprises: providing fuel and oxygen to an internal combustion engine connected to drive an electric generator, to thereby generate electricity; recovering from said engine an exhaust stream including elevated NO[sub x] levels and combined oxygen; adding to said exhaust stream sufficient fuel to create a fuel-rich mixture, the quantity of fuel being sufficient to react with the available oxygen and reduce the NO[sub x], in said exhaust stream; providing said fuel-enriched exhaust stream to a thermal reactor and reacting therein said fuel, NO[sub x]more » and available oxygen, to provide a heated oxygen-depleted stream; cooling said oxygen-depleted stream by passing same through a first heat exchanger; adding conversion oxygen to said cooled stream from said heat exchanger, and passing the cooled oxygen-augmented stream over a first catalyst bed operated at a temperature of about 750 to 1,250 F under overall reducing conditions, the quantity of conversion oxygen added being in stoichiometric excess of the amount of NO[sub x], but less than the amount of combustibles; whereby the NO[sub x] is first oxidized to NO[sub 2], and then the NO[sub 2] is reduced by the excess combustibles; cooling said stream from said first catalyst bed to a temperature of about 450 to 650 F by passing said stream through a second heat exchanger; adding air to the resulting cooled stream to produce a further cooled stream at a temperature of about 400 to 600 F, and having a stoichiometric excess of oxygen; and passing said stream having said stoichiometric excess of oxygen over an oxidizing catalyst bed at said temperature of 400 to 600 F to oxidize remaining excess combustibles, to thereby provide an effluent stream having environmentally safe characteristics.« less

Recovery of useful chemicals from palm oil mill wastewater

NASA Astrophysics Data System (ADS)

Ratanaporn, Yuangsawad; Duangkamol, Na-Ranong; Teruoki, Tago; Takao, Masuda

2017-11-01

A two-step process consisting of pyrolysis of dried sludge and catalytic upgrading of pyrolysed liquid was proposed. Wastewater from a palm oil mill was separated to solid cake and liquid by filtration. The solid cake was dried and pyrolysed at 773 K. Liquid product obtained from the pyrolysis had two immiscible aqueous and oil phases (PL-A and PL-O). Identification of chemicals in PL-A and PL-O indicated that both phases contained various chemicals with unsaturated bonds, such as carboxylic acids and alcohols, however, most of the chemicals could not be identified. Catalytic upgrading of PL-A and PL-O over ZrO2·FeOx were separately performed using a fixed bed reactor at various conditions, T = 513-723 K and mass of catalyst to feed rate = 0.25-10 h. The main components in the liquid products of PL-A upgrading were methanol and acetone whereas they were acetone and phenol in the case of PL-O upgrading. More than 15% of carbon in raw material was deposited on the catalyst. To reduce the carbon deposition, the used catalyst was treated with air at 823 K. This simple treatment could reasonably regenerate the catalyst only for the case of PL-A catalytic upgrading.

Selective hydrogenation of citral over supported Pt catalysts: insight into support effects

NASA Astrophysics Data System (ADS)

Wang, Xiaofeng; Hu, Weiming; Deng, Baolin; Liang, Xinhua

2017-04-01

Highly dispersed platinum (Pt) nanoparticles (NPs) were deposited on various substrates by atomic layer deposition (ALD) in a fluidized bed reactor at 300 °C. The substrates included multi-walled carbon nanotubes (MWCNTs), silica gel (SiO2), commercial γ-Al2O3, and ALD-prepared porous Al2O3 particles (ALD-Al2O3). The results of TEM analysis showed that 1.3 nm Pt NPs were highly dispersed on all different supports. All catalysts were used for the reaction of selective hydrogenation of citral to unsaturated alcohols (UA), geraniol, and nerol. Both the structure and acidity of supports affected the activity and selectivity of Pt catalysts. Pt/SiO2 showed the highest activity due to the strong acidity of SiO2 and the conversion of citral reached 82% after 12 h with a selectivity of 58% of UA. Pt/MWCNTs showed the highest selectivity of UA, which reached 65% with a conversion of 38% due to its unique structure and electronic effect. The cycling experiments indicated that Pt/MWCNTs and Pt/ALD-Al2O3 catalysts were more stable than Pt/SiO2, as a result of the different interactions between the Pt NPs and the supports.

Biomass to hydrogen-rich syngas via catalytic steam gasification of bio-oil/biochar slurry.

PubMed

Chen, Guanyi; Yao, Jingang; Liu, Jing; Yan, Beibei; Shan, Rui

2015-12-01

The catalytic steam gasification of bio-oil/biochar slurry (bioslurry) for hydrogen-rich syngas production was investigated in a fixed-bed reactor using LaXFeO3 (X=Ce, Mg, K) perovskite-type catalysts. The effects of elemental substitution in LaFeO3, temperature, water to carbon molar ratio (WCMR) and bioslurry weight hourly space velocity (WbHSV) were examined. The results showed that La0.8Ce0.2FeO3 gave the best performance among the prepared catalysts and had better catalytic activity and stability than the commercial 14 wt.% Ni/Al2O3. The deactivation caused by carbon deposition and sintering was significantly depressed in the case of La0.8Ce0.2FeO3 catalyst. Both higher temperature and lower WbHSV contributed to more H2 yield. The optimal WCMR was found to be 2, and excessive introducing of steam reduced hydrogen yield. The La0.8Ce0.2FeO3 catalyst gave a maximum H2 yield of 82.01% with carbon conversion of 65.57% under the optimum operating conditions (temperature=800°C, WCMR=2 and WbHSV=15.36h(-1)). Copyright © 2015 Elsevier Ltd. All rights reserved.

Annular core liquid-salt cooled reactor with multiple fuel and blanket zones

DOEpatents

Peterson, Per F.

2013-05-14

A liquid fluoride salt cooled, high temperature reactor having a reactor vessel with a pebble-bed reactor core. The reactor core comprises a pebble injection inlet located at a bottom end of the reactor core and a pebble defueling outlet located at a top end of the reactor core, an inner reflector, outer reflector, and an annular pebble-bed region disposed in between the inner reflector and outer reflector. The annular pebble-bed region comprises an annular channel configured for receiving pebble fuel at the pebble injection inlet, the pebble fuel comprising a combination of seed and blanket pebbles having a density lower than the coolant such that the pebbles have positive buoyancy and migrate upward in said annular pebble-bed region toward the defueling outlet. The annular pebble-bed region comprises alternating radial layers of seed pebbles and blanket pebbles.

The Bosch Process-Performance of a Developmental Reactor and Experimental Evaluation of Alternative Catalysts

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Mansell, J. Matthew

2010-01-01

Bosch-based reactors have been in development at NASA since the 1960's. Traditional operation involves the reduction of carbon dioxide with hydrogen over a steel wool catalyst to produce water and solid carbon. While the system is capable of completely closing the loop on oxygen and hydrogen for Atmosphere Revitalization, steel wool requires a reaction temperature of 650C or higher for optimum performance. The single pass efficiency of the reaction over steel wool has been shown to be less than 10% resulting in a high recycle stream. Finally, the formation of solid carbon on steel wool ultimately fouls the catalyst necessitating catalyst resupply. These factors result in high mass, volume and power demands for a Bosch system. Interplanetary transportation and surface exploration missions of the moon, Mars, and near-earth objects will require higher levels of loop closure than current technology cannot provide. A Bosch system can provide the level of loop closure necessary for these long-term missions if mass, volume, and power can be kept low. The keys to improving the Bosch system lie in reactor and catalyst development. In 2009, the National Aeronautics and Space Administration refurbished a circa 1980's developmental Bosch reactor and built a sub-scale Bosch Catalyst Test Stand for the purpose of reactor and catalyst development. This paper describes the baseline performance of two commercially available steel wool catalysts as compared to performance reported in the 1960's and 80's. Additionally, the results of sub-scale testing of alternative Bosch catalysts, including nickel- and cobalt-based catalysts, are discussed.

Shielded fluid stream injector for particle bed reactor

DOEpatents

Notestein, John E.

1993-01-01

A shielded fluid-stream injector assembly is provided for particle bed reactors. The assembly includes a perforated pipe injector disposed across the particle bed region of the reactor and an inverted V-shaped shield placed over the pipe, overlapping it to prevent descending particles from coming into direct contact with the pipe. The pipe and shield are fixedly secured at one end to the reactor wall and slidably secured at the other end to compensate for thermal expansion. An axially extending housing aligned with the pipe and outside the reactor and an in-line reamer are provided for removing deposits from the inside of the pipe. The assembly enables fluid streams to be injected and distributed uniformly into the particle bed with minimized clogging of injector ports. The same design may also be used for extraction of fluid streams from particle bed reactors.

Two component-three dimensional catalysis

DOEpatents

Schwartz, Michael; White, James H.; Sammells, Anthony F.

2002-01-01

This invention relates to catalytic reactor membranes having a gas-impermeable membrane for transport of oxygen anions. The membrane has an oxidation surface and a reduction surface. The membrane is coated on its oxidation surface with an adherent catalyst layer and is optionally coated on its reduction surface with a catalyst that promotes reduction of an oxygen-containing species (e.g., O.sub.2, NO.sub.2, SO.sub.2, etc.) to generate oxygen anions on the membrane. The reactor has an oxidation zone and a reduction zone separated by the membrane. A component of an oxygen containing gas in the reduction zone is reduced at the membrane and a reduced species in a reactant gas in the oxidation zone of the reactor is oxidized. The reactor optionally contains a three-dimensional catalyst in the oxidation zone. The adherent catalyst layer and the three-dimensional catalyst are selected to promote a desired oxidation reaction, particularly a partial oxidation of a hydrocarbon.

Down-flow moving-bed gasifier with catalyst recycle

DOEpatents

Halow, John S.

1999-01-01

The gasification of coal and other carbonaceous materials by an endothermic gasification reaction is achieved in the presence of a catalyst in a down-flow, moving-bed gasifier. Catalyst is removed along with ash from the gasifier and is then sufficiently heated in a riser/burner by the combustion of residual carbon in the ash to volatilize the catalyst. This volatilized catalyst is returned to the gasifier where it uniformly contacts and condenses on the carbonaceous material. Also, the hot gaseous combustion products resulting from the combustion of the carbon in the ash along with excess air are introduced into the gasifier for providing heat energy used in the endothermic reaction.

Balancing Near-Field Enhancement, Absorption, and Scattering for Effective Antenna-Reactor Plasmonic Photocatalysis.

PubMed

Li, Kun; Hogan, Nathaniel J; Kale, Matthew J; Halas, Naomi J; Nordlander, Peter; Christopher, Phillip

2017-06-14

Efficient photocatalysis requires multifunctional materials that absorb photons and generate energetic charge carriers at catalytic active sites to facilitate a desired chemical reaction. Antenna-reactor complexes are an emerging multifunctional photocatalytic structure where the strong, localized near field of the plasmonic metal nanoparticle (e.g., Ag) is coupled to the catalytic properties of the nonplasmonic metal nanoparticle (e.g., Pt) to enable chemical transformations. With an eye toward sustainable solar driven photocatalysis, we investigate how the structure of antenna-reactor complexes governs their photocatalytic activity in the light-limited regime, where all photons need to be effectively utilized. By synthesizing core@shell/satellite (Ag@SiO 2 /Pt) antenna-reactor complexes with varying Ag nanoparticle diameters and performing photocatalytic CO oxidation, we observed plasmon-enhanced photocatalysis only for antenna-reactor complexes with antenna components of intermediate sizes (25 and 50 nm). Optimal photocatalytic performance was shown to be determined by a balance between maximized local field enhancements at the catalytically active Pt surface, minimized collective scattering of photons out of the catalyst bed by the complexes, and minimal light absorption in the Ag nanoparticle antenna. These results elucidate the critical aspects of local field enhancement, light scattering, and absorption in plasmonic photocatalyst design, especially under light-limited illumination conditions.

Technology development for iron Fischer-Tropsch catalysts. Technical progress report No. 8, July 1, 1992--September 30, 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frame, R.R.; Gala, H.B.

1992-12-31

The objectives of this contract are to develop a technology for the production of active and stable iron Fischer-Tropsch catalysts for use in slurry-phase synthesis reactors and to develop a scaleup procedure for large-scale synthesis of such catalysts for process development and long-term testing in slurry bubble-column reactors. With a feed containing hydrogen and carbon monoxide in the molar ratio of 0.5 to 1.0 to the slurry bubble-column reactor, the catalyst performance target is 88% CO + H{sub 2} conversion at a minimum space velocity of 2.4 NL/hr/gFe. The desired sum of methane and ethane selectivities is no more thanmore » 4%, and the conversion loss per week is not to exceed 1%. Contract Tasks are as follows: 1.0--Catalyst development, 1.1--Technology assessment, 1.2--Precipitated catalyst preparation method development, 1.3--Novel catalyst preparation methods investigation, 1.4--Catalyst pretreatment, 1.5--Catalyst characterization, 2.0--Catalyst testing, 3.0--Catalyst aging studies, and 4.0--Preliminary design and cost estimate of a catalyst synthesis facility. This paper reports progress made on Task 1.« less

Methods for dehydration of sugars and sugar alcohols

DOEpatents

Holladay, Johnathan E [Kennewick, WA; Hu, Jianli [Kennewick, WA; Zhang, Xinjie [Burlington, MA; Wang, Yong [Richland, WA

2010-08-10

The invention includes a method of dehydration of a sugar using a dehydration catalyst and a co-catalyst within a reactor. A sugar is introduced and H.sub.2 is flowed through the reactor at a pressure of less than or equal to about 300 psig to convert at least some of the sugar into an anhydrosugar product. The invention includes a process for producing isosorbide. A starting material comprising sorbitol is flowed into a reactor. H.sub.2 is counter flowed through the reactor. The starting material is exposed to a catalyst in the presence of a co-catalyst which comprises at least one metal. The exposing is conducted at a hydrogen pressure of less than or equal to 300 psig within the reactor and the hydrogen removes at least some of any water present during the exposing and inhibits formation of colored byproducts.

Photocatalytic degradation of mixed gaseous carbonyl compounds at low level on adsorptive TiO2/SiO2 photocatalyst using a fluidized bed reactor.

PubMed

Zhang, Maolin; An, Taicheng; Fu, Jiamo; Sheng, Guoying; Wang, Xinming; Hu, Xiaohong; Ding, Xuejun

2006-06-01

An adsorptive silica-supported titania photocatalyst TiO(2)/SiO(2) was prepared by using nanosized titania (anatase) immobilized on silica gel by the sol-gel technique with the titanium tetra isopropoxide as the main raw material and acetic acid as the acid catalyst. Meanwhile the structure and properties of the TiO(2)/SiO(2) photocatalyst were studied by means of many modern analysis techniques such as TEM, XRD, and BET. Gas-solid heterogeneous photocatalytic decomposition of four carbonyl compounds mixture at low concentration levels over ultraviolet irradiated TiO(2)/SiO(2) photocatalyst were carried out with high degradation efficiencies in a coaxial triple-cylinder-type fluidized bed photocatalytic reactor, which provided efficient continuous contact of ultraviolet photons, silica-supported titania photocatalyst, and gaseous reactants. Experimental results showed that the photocatalyst had a high adsorption performance and a good photocatalytic activity for four carbonyl compounds mixture. Some factors influencing the photocatalytic decomposition of the mixed carbonyl compounds, i.e. the gas flowrate, relative humidity, concentration of oxygen, and illumination time, were discussed in detail. It is found that the photocatalytic reaction rate of four carbonyl compounds decreased in this order: propionaldehyde, acetone, acetaldehyde and formaldehyde.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jarvis, Jacqueline M.; Sudasinghe, Nilusha M.; Albrecht, Karl O.

We apply Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) for direct characterization of iron-porphyrins in hydrothermal liquefaction (HTL) biocrude oils derived from two algae: Tetraselmis sp. and cyanobacteria. The ironporphyrin compounds are shown to cause catalyst bed plugging during hydroprocessing due to iron deposition. Inductively-coupled plasma optical emission spectrometry (ICPOES) was utilized for iron quantitation in the plugged catalyst beds formed through hydroprocessing of the two HTL biocrudes and identifies an enrichment of iron in the upper five centimeters of the catalyst bed for Tetraselmis sp. (Fe=100,728 ppm) and cyanobacteria (Fe=115,450 ppm). Direct infusion FT-ICR MS analysis ofmore » the two HTL biocrudes with optimized instrument conditions facilitates rapid screening and identification of iron-porphyrins without prior chromatographic separation. With FT-ICR MS we identify 138 unique iron-porphyrin compounds in the two HTL biocrudes that are structurally similar to metal-porphyrins (e.g. Ni and V) observed in petroleum. No ironporphyrins are observed in the cyanobacteria HTL biocrude after hydroprocessing, which indicates that iron-porphyrin structures in the HTL biocrude are degraded during hydroprocessing. Hydrodemetallization reactions that occur through hydroprocessing of HTL biocrudes could be responsible for the decomposition of iron-porphyrin structures leading to metal deposition in the catalyst bed that result in catalyst deactivation and bed plugging, and must be addressed for effective upgrading of algal HTL biocrudes.« less

Neutron Fluence And DPA Rate Analysis In Pebble-Bed HTR Reactor Vessel Using MCNP

NASA Astrophysics Data System (ADS)

Hamzah, Amir; Suwoto; Rohanda, Anis; Adrial, Hery; Bakhri, Syaiful; Sunaryo, Geni Rina

2018-02-01

In the Pebble-bed HTR reactor, the distance between the core and the reactor vessel is very close and the media inside are carbon and He gas. Neutron moderation capability of graphite material is theoretically lower than that of water-moderated reactors. Thus, it is estimated much more the fast neutrons will reach the reactor vessel. The fast neutron collisions with the atoms in the reactor vessel will result in radiation damage and could be reducing the vessel life. The purpose of this study was to obtain the magnitude of neutron fluence in the Pebble-bed HTR reactor vessel. Neutron fluence calculations in the pebble-bed HTR reactor vessel were performed using the MCNP computer program. By determining the tally position, it can be calculated flux, spectrum and neutron fluence in the position of Pebble-bed HTR reactor vessel. The calculations results of total neutron flux and fast neutron flux in the reactor vessel of 1.82x108 n/cm2/s and 1.79x108 n/cm2/s respectively. The fast neutron fluence in the reactor vessel is 3.4x1017 n/cm2 for 60 years reactor operation. Radiation damage in stainless steel material caused by high-energy neutrons (> 1.0 MeV) will occur when it has reached the neutron flux level of 1.0x1024 n/cm2. The neutron fluence results show that there is no radiation damage in the Pebble-bed HTR reactor vessel, so it is predicted that it will be safe to operate at least for 60 years.

Continuous preparation of carbon-nanotube-supported platinum catalysts in a flow reactor directly heated by electric current

PubMed Central

dos Santos, Antonio Rodolfo; Kunz, Ulrich; Turek, Thomas

2011-01-01

Summary In this contribution we present for the first time a continuous process for the production of highly active Pt catalysts supported by carbon nanotubes by use of an electrically heated tubular reactor. The synthesized catalysts show a high degree of dispersion and narrow distributions of cluster sizes. In comparison to catalysts synthesized by the conventional oil-bath method a significantly higher electrocatalytic activity was reached, which can be attributed to the higher metal loading and smaller and more uniformly distributed Pt particles on the carbon support. Our approach introduces a simple, time-saving and cost-efficient method for fuel cell catalyst preparation in a flow reactor which could be used at a large scale. PMID:22043252

MicroChannel Reactors for ISRU Applications Using Nanofabricated Catalysts

NASA Astrophysics Data System (ADS)

Carranza, Susana; Makel, Darby B.; Vander Wal, Randall L.; Berger, Gordon M.; Pushkarev, Vladimir V.

2006-01-01

With the new direction of NASA to emphasize the exploration of the Moon, Mars and beyond, quick development and demonstration of efficient systems for In-Situ Resources Utilization (ISRU) is more critical and timely than ever before. Affordable planning and execution of prolonged manned space missions depend upon the utilization of local resources and the waste products which are formed in manned spacecraft and surface bases. This paper presents current development of miniaturized chemical processing systems that combine microchannel reactor design with nanofabricated catalysts. Carbon nanotubes (CNT) are used to produce a nanostructure within microchannel reactors, as support for catalysts. By virtue of their nanoscale dimensions, nanotubes geometrically restrict the catalyst particle size that can be supported upon the tube walls. By confining catalyst particles to sizes smaller than the CNT diameter, a more uniform catalyst particle size distribution may be maintained. The high dispersion permitted by the vast surface area of the nanoscale material serves to retain the integrity of the catalyst by reducing sintering or coalescence. Additionally, catalytic efficiency increases with decreasing catalyst particle size (reflecting higher surface area per unit mass) while chemical reactivity frequently is enhanced at the nanoscale. Particularly significant is the catalyst exposure. Rather than being confined within a porous material or deposited upon a 2-d surface, the catalyst is fully exposed to the reactant gases by virtue of the nanofabricated support structure. The combination of microchannel technology with nanofabricated catalysts provides a synergistic effect, enhancing both technologies with the potential to produce much more efficient systems than either technology alone. The development of highly efficient microchannel reactors will be applicable to multiple ISRU programs. By selection of proper nanofabricated catalysts, the microchannel reactors can be designed for the processes that generate the most benefit for each mission, from early demonstration missions to long term settlements.

Dual reactor for in situ/operando fluorescent mode XAS studies of sample containing low-concentration 3d or 5d metal elements

NASA Astrophysics Data System (ADS)

Nguyen, Luan; Tang, Yu; Li, Yuting; Zhang, Xiaoyan; Wang, Ding; Tao, Franklin Feng

2018-05-01

Transition metal elements are the most important elements of heterogeneous catalysts used for chemical and energy transformations. Many of these catalysts are active at a temperature higher than 400 °C. For a catalyst containing a 3d or 5d metal element with a low concentration, typically their released fluorescence upon the K-edge or L-edge adsorption of X-rays is collected for the analysis of chemical and coordination environments of these elements. However, it is challenging to perform in situ/operando X-ray absorption spectroscopy (XAS) studies of elements of low-energy absorption edges at a low concentration in a catalyst during catalysis at a temperature higher than about 450 °C. Here a unique reaction system consisting two reactors, called a dual reactor system, was designed for performing in situ or operando XAS studies of these elements of low-energy absorption edges in a catalyst at a low concentration during catalysis at a temperature higher than 450 °C in a fluorescent mode. This dual-reactor system contains a quartz reactor for preforming high-temperature catalysis up to 950 °C and a Kapton reactor remaining at a temperature up to 450 °C for collecting data in the same gas of catalysis. With this dual reactor, chemical and coordination environments of low-concentration metal elements with low-energy absorption edges such as the K-edge of 3d metals including Ti, V, Cr, Mn, Fe, Co, Ni, and Cu and L edge of 5d metals including W, Re, Os, Ir, Pt, and Au can be examined through first performing catalysis at a temperature higher than 450 °C in the quartz reactor and then immediately flipping the catalyst in the same gas flow to the Kapton reactor remained up to 450 °C to collect data. The capability of this dual reactor was demonstrated by tracking the Mn K-edge of the MnOx/Na2WO4 catalyst during activation in the temperature range of 300-900 °C and catalysis at 850 °C.

Catalytic multi-stage process for hydroconversion and refining hydrocarbon feeds

DOEpatents

Comolli, Alfred G.; Lee, Lap-Keung

2001-01-01

A multi-stage catalytic hydrogenation and hydroconversion process for heavy hydrocarbon feed materials such as coal, heavy petroleum fractions, and plastic waste materials. In the process, the feedstock is reacted in a first-stage, back-mixed catalytic reactor with a highly dispersed iron-based catalyst having a powder, gel or liquid form. The reactor effluent is pressure-reduced, vapors and light distillate fractions are removed overhead, and the heavier liquid fraction is fed to a second stage back-mixed catalytic reactor. The first and second stage catalytic reactors are operated at 700-850.degree. F. temperature, 1000-3500 psig hydrogen partial pressure and 20-80 lb./hr per ft.sup.3 reactor space velocity. The vapor and light distillates liquid fractions removed from both the first and second stage reactor effluent streams are combined and passed to an in-line, fixed-bed catalytic hydrotreater for heteroatom removal and for producing high quality naphtha and mid-distillate or a full-range distillate product. The remaining separator bottoms liquid fractions are distilled at successive atmospheric and vacuum pressures, low and intermediate-boiling hydrocarbon liquid products are withdrawn, and heavier distillate fractions are recycled and further upgraded to provide additional low-boiling hydrocarbon liquid products. This catalytic multistage hydrogenation process provides improved flexibility for hydroprocessing the various carbonaceous feedstocks and adjusting to desired product structures and for improved economy of operations.

VUV photo-oxidation of gaseous benzene combined with ozone-assisted catalytic oxidation: Effect on transition metal catalyst

NASA Astrophysics Data System (ADS)

Huang, Haibao; Lu, Haoxian; Zhan, Yujie; Liu, Gaoyuan; Feng, Qiuyu; Huang, Huiling; Wu, Muyan; Ye, Xinguo

2017-01-01

Volatile organic compounds (VOCs) cause the major air pollution concern. In this study, a series of ZSM-5 supported transition metals were prepared by impregnation method. They were combined with vacuum UV (VUV) photo-oxidation in a continuous-flow packed-bed reactor and used for the degradation of benzene, a typical toxic VOCs. Compared with VUV photo-oxidation alone, the introduction of catalysts can greatly enhance benzene oxidation under the help of O3, the by-products from VUV irradiation, via ozone-assisted catalytic oxidation (OZCO). The catalytic activity of transition metals towards benzene oxidation followed the order: Mn > Co > Cu > Ni > Fe. Mn achieved the best catalytic activity due to the strongest capability for O3 catalytic decomposition and utilization. Benzene and O3 removal efficiency reached as high as 97% and 100% after 360 min, respectively. O3 was catalytically decomposed, generating highly reactive oxidants such as rad OH and rad O for benzene oxidation.

Production of aromatics from di- and polyoxygenates

DOEpatents

Beck, Taylor; Blank, Brian; Jones, Casey; Woods, Elizabeth; Cortright, Randy

2016-08-02

Methods, catalysts, and reactor systems for producing in high yield aromatic chemicals and liquid fuels from a mixture of oxygenates comprising di- and polyoxygenates are disclosed. Also disclosed are methods, catalysts, and reactor systems for producing aromatic chemicals and liquid fuels from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like; and methods, catalysts, and reactor systems for producing the mixture of oxygenates from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like. The disclosed catalysts for preparing the mixture of oxygenates comprise a Ni.sub.nSn.sub.m alloy and a crystalline alumina support.

Production of aromatics from di- and polyoxygenates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beck, Taylor; Blank, Brian; Jones, Casey

Methods, catalysts, and reactor systems for producing in high yield aromatic chemicals and liquid fuels from a mixture of oxygenates comprising di- and polyoxygenates are disclosed. Also disclosed are methods, catalysts, and reactor systems for producing aromatic chemicals and liquid fuels from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like; and methods, catalysts, and reactor systems for producing the mixture of oxygenates from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like. The disclosed catalysts for preparing the mixture of oxygenates comprise a Ni.sub.nSn.sub.m alloy and a crystalline aluminamore » support.« less

Production of aromatics from di- and polyoxygenates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beck, Taylor; Blank, Brian; Jones, Casey

Methods, catalysts, and reactor systems for producing in high yield aromatic chemicals and liquid fuels from a mixture of oxygenates comprising di- and polyoxygenates are disclosed. Also disclosed are methods, catalysts, and reactor systems for producing aromatic chemicals and liquid fuels from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like; and methods, catalysts, and reactor systems for producing the mixture of oxygenates from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like. The disclosed catalysts for preparing the mixture of oxygenates comprise a Group VIII metal and a crystallinemore » alumina support.« less

Modeling of methanol decomposition on Pt/CeO2/ZrO2 catalyst in a packed bed microreactor

NASA Astrophysics Data System (ADS)

Pohar, Andrej; Belavič, Darko; Dolanc, Gregor; Hočevar, Stanko

2014-06-01

Methanol decomposition on Pt/CeO2/ZrO2 catalyst is studied inside a packed bed microreactor in the temperature range of 300-380 °C. The microreactor is fabricated using low-temperature co-fired ceramic (LTCC) technology, which is well suited for the production of relatively complex three-dimensional structures. It is packed with 2 wt% Pt-CeO2 catalyst, which is deposited onto ZrO2 spherical particles. A 1D mathematical model, which incorporates diffusion, convection and mass transfer through the boundary layer to the catalyst particles, as well as a 3D computational fluid dynamics model, are developed to describe the methanol decomposition process inside the packed bed. The microreactor exhibits reliable operation and no catalyst deactivation was observed during three months of experimentation. A comparison between the 1D mathematical model and the 3D model, considering the full 3D geometry of the microreactor is made and the differences between the models are identified and evaluated.

Down-flow moving-bed gasifier with catalyst recycle

DOEpatents

Halow, J.S.

1999-04-20

The gasification of coal and other carbonaceous materials by an endothermic gasification reaction is achieved in the presence of a catalyst in a down-flow, moving-bed gasifier. Catalyst is removed along with ash from the gasifier and is then sufficiently heated in a riser/burner by the combustion of residual carbon in the ash to volatilize the catalyst. This volatilized catalyst is returned to the gasifier where it uniformly contacts and condenses on the carbonaceous material. Also, the hot gaseous combustion products resulting from the combustion of the carbon in the ash along with excess air are introduced into the gasifier for providing heat energy used in the endothermic reaction. 1 fig.

Alternative Fuels Research Laboratory

NASA Technical Reports Server (NTRS)

Surgenor, Angela D.; Klettlinger, Jennifer L.; Nakley, Leah M.; Yen, Chia H.

2012-01-01

NASA Glenn has invested over $1.5 million in engineering, and infrastructure upgrades to renovate an existing test facility at the NASA Glenn Research Center (GRC), which is now being used as an Alternative Fuels Laboratory. Facility systems have demonstrated reliability and consistency for continuous and safe operations in Fischer-Tropsch (F-T) synthesis and thermal stability testing. This effort is supported by the NASA Fundamental Aeronautics Subsonic Fixed Wing project. The purpose of this test facility is to conduct bench scale F-T catalyst screening experiments. These experiments require the use of a synthesis gas feedstock, which will enable the investigation of F-T reaction kinetics, product yields and hydrocarbon distributions. Currently the facility has the capability of performing three simultaneous reactor screening tests, along with a fourth fixed-bed reactor for catalyst activation studies. Product gas composition and performance data can be continuously obtained with an automated gas sampling system, which directly connects the reactors to a micro-gas chromatograph (micro GC). Liquid and molten product samples are collected intermittently and are analyzed by injecting as a diluted sample into designated gas chromatograph units. The test facility also has the capability of performing thermal stability experiments of alternative aviation fuels with the use of a Hot Liquid Process Simulator (HLPS) (Ref. 1) in accordance to ASTM D 3241 "Thermal Oxidation Stability of Aviation Fuels" (JFTOT method) (Ref. 2). An Ellipsometer will be used to study fuel fouling thicknesses on heated tubes from the HLPS experiments. A detailed overview of the test facility systems and capabilities are described in this paper.

Sabatier Catalyst Poisoning Investigation

NASA Technical Reports Server (NTRS)

Nallette, Tim; Perry, Jay; Abney, Morgan; Knox, Jim; Goldblatt, Loel

2013-01-01

The Carbon Dioxide Reduction Assembly (CRA) on the International Space Station (ISS) has been operational since 2010. The CRA uses a Sabatier reactor to produce water and methane by reaction of the metabolic CO2 scrubbed from the cabin air and the hydrogen byproduct from the water electrolysis system used for metabolic oxygen generation. Incorporating the CRA into the overall air revitalization system has facilitated life support system loop closure on the ISS reducing resupply logistics and thereby enhancing longer term missions. The CRA utilizes CO2 which has been adsorbed in a 5A molecular sieve within the Carbon Dioxide Removal Assembly, CDRA. There is a potential of compounds with molecular dimensions similar to, or less than CO2 to also be adsorbed. In this fashion trace contaminants may be concentrated within the CDRA and subsequently desorbed with the CO2 to the CRA. Currently, there is no provision to remove contaminants prior to entering the Sabatier catalyst bed. The risk associated with this is potential catalyst degradation due to trace organic contaminants in the CRA carbon dioxide feed acting as catalyst poisons. To better understand this risk, United Technologies Aerospace System (UTAS) has teamed with MSFC to investigate the impact of various trace contaminants on the CRA catalyst performance at relative ISS cabin air concentrations and at about 200/400 times of ISS concentrations, representative of the potential concentrating effect of the CDRA molecular sieve. This paper summarizes our initial assessment results.

A comparison of prototype compound parabolic collector-reactors (CPC) on the road to SOLARDETOX technology.

PubMed

Funken, K H; Sattler, C; Milow, B; De Oliveira, L; Blanco, J; Fernández, P; Malato, S; Brunott, M; Dischinge, N; Tratzky, S; Musci, M; de Oliveira, J C

2001-01-01

Solar photocatalytic detoxification of non-biodegradable chlorinated hydrocarbon solvents (NBCS) is carried out in different concentrating and non concentrating devices using TiO2 as a photocatalyst fixed on the inner surface of the reaction tubes or as a slurry catalyst which has to be removed from the treated water. The reaction is most effective using 200 mg/l of TiO2 as a slurry in a non concentrating CPC reactor. The concentrating parabolic trough reactor has a poor activity because of its minor irradiated reactor surface. Catalyst coated glass tubes are less efficient then the used slurry catalyst. Their advantage is that no catalyst has not to be removed from the treated water and there is no loss of activity during treatment. Yet their physical stability is not sufficient to be competitive to the slurry catalyst. Nevertheless the degradation results are very promising and will possibly lead to commercial applications of this technology.

A submerged ceramic membrane reactor for the p-nitrophenol hydrogenation over nano-sized nickel catalysts.

PubMed

Chen, R Z; Sun, H L; Xing, W H; Jin, W Q; Xu, N P

2009-02-01

The catalytic hydrogenation of p-nitrophenol to p-aminophenol over nano-sized nickel catalysts was carried out in a submerged ceramic membrane reactor. It has been demonstrated that the submerged ceramic membrane reactor is more suitable for the p-nitrophenol hydrogenation over nano-sized nickel catalysts compared with the side-stream ceramic membrane reactor, and the membrane module configuration has a great influence on the reaction rate of p-nitrophenol hydrogenation and the membrane treating capacity. The deactivation of nano-sized nickel is mainly caused by the adsorption of impurity on the surface of nickel and the increase of oxidation degree of nickel.

Surface hydrophobicity and acidity effect on alumina catalyst in catalytic methanol dehydration reaction

PubMed Central

Osman, Ahmed I; Thompson, Jillian; Halawy, Samih A; Mohamed, Mohamed A

2017-01-01

Abstract BACKGROUND Methanol to dimethyl ether (MTD) is considered one of the main routes for the production of clean bio‐fuel. The effect of copper loading on the catalytic performance of different phases of alumina that formed by calcination at two different temperatures was examined for the dehydration of methanol to dimethyl ether (DME). RESULTS A range of Cu loadings of (1, 2, 4, 6, 10 and 15% Cu wt/wt) on Al2O3 calcined at 350 and 550 °C were prepared and characterized by TGA, XRD, BET, NH3‐TPD, TEM, H2‐TPR, SEM, EDX, XPS and DRIFT‐Pyridine techniques. The prepared catalysts were used in a fixed bed reactor under reaction conditions in which the temperature ranged from 180–300 °C with weight hourly space velocity (WHSV) = 12.1 h‐1. It was observed that all catalysts calcined at 550 °C (γ‐Al2O3 support phase) exhibited higher activity than those calcined at 350 °C (γ‐AlOOH), and this is due to the phase support change. Furthermore, the optimum Cu loading was found to be 6% Cu/γ‐Al2O3 with this catalyst also showing a high degree of stability under steady state conditions and this is attributed to the enhancement in surface acidity and hydrophobicity. CONCLUSION The addition of copper to the support improved the catalyst properties and activity. For all the copper modified catalysts, the optimum catalyst with high degree of activity and stability was 6% copper loaded on gamma alumina. © 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:29200585

Continuous biological waste gas treatment in stirred trickle-bed reactor with discontinuous removal of biomass.

PubMed

Laurenzis, A; Heits, H; Wübker, S; Heinze, U; Friedrich, C; Werner, U

1998-02-20

A new reactor for biological waste gas treatment was developed to eliminate continuous solvents from waste gases. A trickle-bed reactor was chosen with discontinuous movement of the packed bed and intermittent percolation. The reactor was operated with toluene as the solvent and an optimum average biomass concentration of between 5 and 30 kg dry cell weight per cubic meter packed bed (m3pb). This biomass concentration resulted in a high volumetric degradation rate. Reduction of surplus biomass by stirring and trickling caused a prolonged service life and prevented clogging of the trickle bed and a pressure drop increase. The pressure drop after biomass reduction was almost identical to the theoretical pressure drop as calculated for the irregular packed bed without biomass. The reduction in biomass and intermittent percolation of mineral medium resulted in high volumetric degradation rates of about 100 g of toluene m-3pb h-1 at a load of 150 g of toluene m-3pb h-1. Such a removal rate with a trickle-bed reactor was not reported before. Copyright 1998 John Wiley & Sons, Inc.

Microchannel Reactors for ISRU Applications

NASA Astrophysics Data System (ADS)

Carranza, Susana; Makel, Darby B.; Blizman, Brandon; Ward, Benjamin J.

2005-02-01

Affordable planning and execution of prolonged manned space missions depend upon the utilization of local resources and the waste products which are formed in manned spacecraft and surface bases. Successful in-situ resources utilization (ISRU) will require component technologies which provide optimal size, weight, volume, and power efficiency. Microchannel reactors enable the efficient chemical processing of in situ resources. The reactors can be designed for the processes that generate the most benefit for each mission. For instance, propellants (methane) can be produced from carbon dioxide from the Mars atmosphere using the Sabatier reaction and ethylene can be produced from the partial oxidation of methane. A system that synthesizes ethylene could be the precursor for systems to synthesize ethanol and polyethylene. Ethanol can be used as a nutrient for Astrobiology experiments, as well as the production of nutrients for human crew (e.g. sugars). Polyethylene can be used in the construction of habitats, tools, and replacement parts. This paper will present recent developments in miniature chemical reactors using advanced Micro Electro Mechanical Systems (MEMS) and microchannel technology to support ISRU of Mars and lunar missions. Among other applications, the technology has been demonstrated for the Sabatier process and for the partial oxidation of methane. Microchannel reactors were developed based on ceramic substrates as well as metal substrates. In both types of reactors, multiple layers coated with catalytic material are bonded, forming a monolithic structure. Such reactors are readily scalable with the incorporation of extra layers. In addition, this reactor structure minimizes pressure drop and catalyst settling, which are common problems in conventional packed bed reactors.

NREL's Thermochemical Conversion Facility Video Text Version | Bioenergy |

Science.gov Websites

steady-state. We use a tandem fast pyrolysis reactor and Davison recirculating reactor system to study ex be continually added and withdrawn so we can study catalyst activity and product composition at catalyst. Here we can study the impact of catalyst formulation and processing conditions on bio-oil

Effects of thermal pretreatment and catalyst on biomass gasification efficiency and syngas composition

DOE PAGES

Cheah, Singfoong; Jablonski, Whitney S.; Olstad, Jessica L.; ...

2016-09-16

This work explores the combined effects of thermal pretreatment and using a catalyst in situ on gasification carbon conversion efficiency, as well as product gas and tar content and compositions. To compare the effects of thermal pretreatment, pelletized and ground oak with three different levels of thermal pretreatment were gasified in a fluidized bed reactor. The pretreatments applied to the oak were (1) pelletization, (2) drying at 180 °C in air, and (3) torrefaction at 270 °C in nitrogen. The oak dried at 180 °C produced syngas of similar quality and approximately the same amount of char as untreated oak.more » Torrefaction at 270 °C resulted in syngas with a higher hydrogen to CO ratio, lower methane, and less than half of the total tar -- all of which are desirable properties in terms of product gas quality. However, the oak torrefied at 270 °C also produced more than two times the amount of char as the untreated, pelletized oak. To determine the effect of catalyst, a series of experiments were conducted using olivine impregnated with nickel and cerium as the fluidized bed material in the gasifier. These tests showed that modified olivine can improve hydrogen production and reduce methane and tar levels in the syngas. The result was observed for both treated and untreated oak; although the effect was more substantial for untreated oak, for which the use of modified olivine reduced tar concentrations in the product gas by 60%, with a larger reduction in heavier tars than lighter tars. Furthermore, this result is important because reduction in heavier tar plays a more important role in benefitting downstream operations.« less

Synthesis of coiled carbon nanotubes on Co/Al2O3 catalysts in a fluidised-bed

NASA Astrophysics Data System (ADS)

Liu, Jun; Harris, Andrew T.

2010-02-01

Mixtures of regularly coiled and straight multi-walled carbon nanotubes (MWNTs) were synthesised on alumina supported Co catalysts prepared by pH controlled, wet impregnation. The synthesis reaction was performed under C2H2:H2:N2 at 750 °C in a fluidised-bed for 30 min. Scanning electron microscopy/energy dispersive X-ray spectroscopy shows good distribution of the active Co particles on the surface of the alumina support. Determined from 10 individual SEM images from the same product batch, the CNTs present are typically from 10 to 40 nm in diameter. Thermogravimetric analysis (TGA) and Raman spectroscopy indicate the total oxidative weight loss is independent of pH during catalyst preparation. This study is the first to report the use of a fluidised-bed for the synthesis of coiled MWNTs, using alumina supported Co catalysts.

Butanol Dehydration over V₂O₅-TiO₂/MCM-41 Catalysts Prepared via Liquid Phase Atomic Layer Deposition.

PubMed

Choi, Hyeonhee; Bae, Jung-Hyun; Kim, Do Heui; Park, Young-Kwon; Jeon, Jong-Ki

2013-04-29

MCM-41 was used as a support and, by using atomic layer deposition (ALD) in the liquid phase, a catalyst was prepared by consecutively loading titanium oxide and vanadium oxide to the support. This research analyzes the effect of the loading amount of vanadium oxide on the acidic characteristics and catalytic performance in the dehydration of butanol. The physical and chemical characteristics of the TiO₂-V₂O₅/MCM-41 catalysts were analyzed using XRF, BET, NH₃-TPD, XRD, Py-IR, and XPS. The dehydration reaction of butanol was performed in a fixed bed reactor. For the samples with vanadium oxide loaded to TiO₂/MCM-41 sample using the liquid phase ALD method, it was possible to increase the loading amount until the amount of vanadium oxide reached 12.1 wt %. It was confirmed that the structural properties of the mesoporous silica were retained well after titanium oxide and vanadium loading. The NH₃-TPD and Py-IR results indicated that weak acid sites were produced over the TiO₂/MCM-41 samples, which is attributed to the generation of Lewis acid sites. The highest activity of the V₂O₅(12.1)-TiO₂/MCM-41 catalyst in 2-butanol dehydration is ascribed to it having the highest number of Lewis acid sites, as well as the highest vanadium dispersion.

Pilot plant operation of a nonadiabatic methanation reactor. [15 refs. ; Raney nickel catalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schehl, R.R.; Pennline, H.W.; Strakey, J.P.

The design and operation of a pilot plant scale hybrid methanation reactor is discussed. The hybrid methanator, utilizing a finned, Raney nickel coated insert, consolidates features of the tube-wall and hot-gas-recycle methanation reactors. Data are presented from four tests lasting from 3/sup 1///sub 2/ weeks to three months. Topics discussed include conversion, product yields, catalyst properties, and reactor temperature profiles. A one-dimensional mathematical model capable of explaining reactor performance trends is employed.

Method of shielding a liquid-metal-cooled reactor

DOEpatents

Sayre, Robert K.

1978-01-01

The primary heat transport system of a nuclear reactor -- particularly for a liquid-metal-cooled fast-breeder reactor -- is shielded and protected from leakage by establishing and maintaining a bed of a powdered oxide closely and completely surrounding all components thereof by passing a gas upwardly therethrough at such a rate as to slightly expand the bed to the extent that the components of the system are able to expand without damage and yet the particles of the bed remain close enough so that the bed acts as a guard vessel for the system. Preferably the gas contains 1 to 10% oxygen and the gas is passed upwardly through the bed at such a rate that the lower portion of the bed is a fixed bed while the upper portion is a fluidized bed, the line of demarcation therebetween being high enough that the fixed bed portion of the bed serves as guard vessel for the system.

Development of a trickle bed reactor of electro-Fenton process for wastewater treatment.

PubMed

Lei, Yangming; Liu, Hong; Shen, Zhemin; Wang, Wenhua

2013-10-15

To avoid electrolyte leakage and gas bubbles in the electro-Fenton (E-Fenton) reactors using a gas diffusion cathode, we developed a trickle bed cathode by coating a layer composed of carbon black and polytetrafluoroethylene (C-PTFE) onto graphite chips instead of carbon cloth. The trickle bed cathode was optimized by single-factor and orthogonal experiments, in which carbon black, PTFE, and a surfactant were considered as the determinant of the performance of graphite chips. In the reactor assembled by the trickle bed cathode, H2O2 was generated with a current of 0.3A and a current efficiency of 60%. This performance was attributed to the fine distribution of electrolyte and air, as well as the effective oxygen transfer from the gas phase to the electrolyte-cathode interface. In terms of H2O2 generation and current efficiency, the developed trickle bed reactor had a performance comparable to that of the conventional E-Fenton reactor using a gas diffusion cathode. Further, 123 mg L(-1) of reactive brilliant red X-3B in aqueous solution was decomposed in the optimized trickle bed reactor as E-Fenton reactor. The decolorization ratio reached 97% within 20 min, and the mineralization reached 87% within 3h. Copyright © 2013 Elsevier B.V. All rights reserved.

Discharge Characteristics of Series Surface/Packed-Bed Discharge Reactor Diven by Bipolar Pulsed Power

NASA Astrophysics Data System (ADS)

Hu, Jian; Jiang, Nan; Li, Jie; Shang, Kefeng; Lu, Na; Wu, Yan; Mizuno, Akira

2016-03-01

The discharge characteristics of the series surface/packed-bed discharge (SSPBD) reactor driven by bipolar pulse power were systemically investigated in this study. In order to evaluate the advantages of the SSPBD reactor, it was compared with traditional surface discharge (SD) reactor and packed-bed discharge (PBD) reactor in terms of the discharge voltage, discharge current, and ozone formation. The SSPBD reactor exhibited a faster rising time and lower tail voltage than the SD and PBD reactors. The distribution of the active species generated in different discharge regions of the SSPBD reactor was analyzed by optical emission spectra and ozone analysis. It was found that the packed-bed discharge region (3.5 mg/L), rather than the surface discharge region (1.3 mg/L) in the SSPBD reactor played a more important role in ozone generation. The optical emission spectroscopy analysis indicated that more intense peaks of the active species (e.g. N2 and OI) in the optical emission spectra were observed in the packed-bed region. supported by National Natural Science Foundation of China (No. 51177007), the Joint Funds of National Natural Science Foundation of China (No. U1462105), and Dalian University of Technology Fundamental Research Fund of China (No. DUT15RC(3)030)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agblevor, Foster A.; Elliott, Douglas C.; Santosa, Daniel M.

Pinyon juniper biomass feedstocks, which cover a large acreage of rangeland in the western United States, are being eradicated and, therefore, considered as a convenient biomass feedstock for biofuel production. Pinyon juniper whole biomass (wood, bark, and leaves) were pyrolyzed in a pilot-scale bubbling fluidized-bed reactor at 450 °C, and the noncondensable gases were recycled to fluidize the reactor. Red mud was used as the in situ catalyst for the pyrolysis of the pinyon juniper biomass. The pyrolysis products were condensed in three stages, and products were analyzed for physicochemical properties. The condenser oil formed two phases with the aqueousmore » fraction, whereas the electrostatic precipitator oils formed a single phase. The oil pH was 3.3; the higher heating value (HHV) was 28 MJ/kg; and the viscosity was less than 100 cP. There was a direct correlation between the viscosity of the oils and the alcohol/ether content of the oils, and this was also related to the aging rate of the oils. The catalytic pyrolysis oils were hydrotreated in a continuous single-stage benchtop hydrotreater to produce hydrocarbon fuels with a density of 0.80$-$0.82 cm 3/g. The hydrotreater ran continuously for over 300 h with no significant catalyst deactivation or coke formation. This is the first time that such a long single-stage hydrotreatment has been demonstrated on biomass catalytic pyrolysis oils.« less

Production of Biodiesel Using a Membrane Reactor to Minimize Separation Cost

NASA Astrophysics Data System (ADS)

Olagunju, O. A.; Musonge, P.

2017-07-01

This study investigates the performance of a packed bed membrane reactor in the transesterification process of triglycerides to methyl ester using soyabean oil as feedstock. A TiO2/Al2O3 ceramic microporous membrane was selected due to its chemical inert nature and thermal stability to selectively remove the product from the reaction medium. CaO impregnated on the surface of activated carbon was packed into the membrane and acted as catalyst. The synthesized catalyst had a total loading of 40.50 % and was characterized by XRD and temperature-programmed desorption of CO2 (CO2-TPD). The crude biodiesel produced was micro-filtered by the ceramic membrane with a pore size of 0.02 μm to retain the unreacted oil and free glycerol, at the transmembrane pressure of 100 KPa. The best condition was achieved with a temperature of 65 °C, methanol/oil molar ratio of 6:1 for 150 minutes, which resulted in the highest FAME yield of 94 %. Methyl ester produced met the ASTM D6751 and SANS 1935 specifications. The product obtained was mainly composed of methyl esters. Glycerol was not detected in the product stream due to the ability of the membrane to retain the glycerol and the unreacted oil in the medium, which solved the issue of glycerol separation from biodiesel.

Fast start-up reactor for partial oxidation of methane with electrically-heated metallic monolith catalyst

NASA Astrophysics Data System (ADS)

Jung, Heon; Yoon, Wang Lai; Lee, Hotae; Park, Jong Soo; Shin, Jang Sik; La, Howon; Lee, Jong Dae

A palladium-washcoated metallic monolith catalyst is applied to the partial oxidation of methane to syngas. This catalyst is highly active at a gas hourly space velocity (GHSV) of 100,000 h -1. The compact partial oxidation (POX) reactor equipped with both 96 cc of the metallic monolith catalyst and an electrically-heated catalyst (EHC) has a start-up time of less than 1.5 min and a syngas generation capacity of 9.5 Nm 3 h -1. The POX reaction is sustained without the need for an external heater. With the stand-alone POX reactor, the methane conversion can be increased either by preheating the reactant mixture heat-exchanged with the product gas, or by supplying a larger amount of oxygen than is necessary for the reaction stoichiometry.

EMERGING TECHNOLOGY BULLETIN: SPOUTED BED REACTOR

EPA Science Inventory

The Spouted Bed Reactor (SBR) technology utilizes the unique attributes of the "spouting " fluidization regime, which can provide heat transfer rates comparable to traditional fluid beds, while providing robust circulation of highly heterogeneous solids, concurrent with very agg...

Mathematical modeling of methyl ester concentration distribution in a continuous membrane tubular reactor and comparison with conventional tubular reactor

NASA Astrophysics Data System (ADS)

Talaghat, M. R.; Jokar, S. M.; Modarres, E.

2017-10-01

The reduction of fossil fuel resources and environmental issues made researchers find alternative fuels include biodiesels. One of the most widely used methods for production of biodiesel on a commercial scale is transesterification method. In this work, the biodiesel production by a transesterification method was modeled. Sodium hydroxide was considered as a catalyst to produce biodiesel from canola oil and methanol in a continuous tubular ceramic membranes reactor. As the Biodiesel production reaction from triglycerides is an equilibrium reaction, the reaction rate constants depend on temperature and related linearly to catalyst concentration. By using the mass balance for a membrane tubular reactor and considering the variation of raw materials and products concentration with time, the set of governing equations were solved by numerical methods. The results clearly show the superiority of membrane reactor than conventional tubular reactors. Afterward, the influences of molar ratio of alcohol to oil, weight percentage of the catalyst, and residence time on the performance of biodiesel production reactor were investigated.

METHOD FOR SENSING DEGREE OF FLUIDIZATION IN FLUIDIZED BED

DOEpatents

Levey, R.P. Jr.; Fowler, A.H.

1961-12-12

A method is given for detecting, indicating, and controlling the degree of fluidization in a fluid-bed reactor into which powdered material is fed. The method comprises admitting of gas into the reactor, inserting a springsupported rod into the powder bed of the reactor, exciting the rod to vibrate at its resonant frequency, deriving a signal responsive to the amplitude of vibi-ation of the rod and spring, the signal being directiy proportional to the rate of flow of the gas through the reactor, displaying the signal to provide an indication of the degree of fluidization within the reactor, and controlling the rate of gas flow into the reactor until said signal stabilizes at a constant value to provide substantially complete fluidization within the reactor. (AEC)

Stabilization of Hydrogen Production via Methanol Steam Reforming in Microreactor by Al2O3 Nano-Film Enhanced Catalyst Adhesion.

PubMed

Jeong, Heondo; Na, Jeong-Geol; Jang, Min Su; Ko, Chang Hyun

2016-05-01

In hydrogen production by methanol steam reforming reaction with microchannel reactor, Al2O3 thin film formed by atomic layer deposition (ALD) was introduced on the surface of microchannel reactor prior to the coating of catalyst particles. Methanol conversion rate and hydrogen production rate, increased in the presence of Al2O3 thin film. Over-view and cross-sectional scanning electron microscopy study showed that the adhesion between catalyst particles and the surface of microchannel reactor enhanced due to the presence of Al2O3 thin film. The improvement of hydrogen production rate inside the channels of microreactor mainly came from the stable fixation of catalyst particles on the surface of microchannels.

Future Challenges in Heterogeneous Catalysis: Understanding Catalysts under Dynamic Reaction Conditions

PubMed Central

Kalz, Kai F.; Kraehnert, Ralph; Dvoyashkin, Muslim; Dittmeyer, Roland; Gläser, Roger; Krewer, Ulrike; Reuter, Karsten

2016-01-01

Abstract In the future, (electro‐)chemical catalysts will have to be more tolerant towards a varying supply of energy and raw materials. This is mainly due to the fluctuating nature of renewable energies. For example, power‐to‐chemical processes require a shift from steady‐state operation towards operation under dynamic reaction conditions. This brings along a number of demands for the design of both catalysts and reactors, because it is well‐known that the structure of catalysts is very dynamic. However, in‐depth studies of catalysts and catalytic reactors under such transient conditions have only started recently. This requires studies and advances in the fields of 1) operando spectroscopy including time‐resolved methods, 2) theory with predictive quality, 3) kinetic modelling, 4) design of catalysts by appropriate preparation concepts, and 5) novel/modular reactor designs. An intensive exchange between these scientific disciplines will enable a substantial gain of fundamental knowledge which is urgently required. This concept article highlights recent developments, challenges, and future directions for understanding catalysts under dynamic reaction conditions. PMID:28239429

Reactor for tracking catalyst nanoparticles in liquid at high temperature under a high-pressure gas phase with X-ray absorption spectroscopy.

PubMed

Nguyen, Luan; Tao, Franklin Feng

2018-02-01

Structure of catalyst nanoparticles dispersed in liquid phase at high temperature under gas phase of reactant(s) at higher pressure (≥5 bars) is important for fundamental understanding of catalytic reactions performed on these catalyst nanoparticles. Most structural characterizations of a catalyst performing catalysis in liquid at high temperature under gas phase at high pressure were performed in an ex situ condition in terms of characterizations before or after catalysis since, from technical point of view, access to the catalyst nanoparticles during catalysis in liquid phase at high temperature under high pressure reactant gas is challenging. Here we designed a reactor which allows us to perform structural characterization using X-ray absorption spectroscopy including X-ray absorption near edge structure spectroscopy and extended X-ray absorption fine structure spectroscopy to study catalyst nanoparticles under harsh catalysis conditions in terms of liquid up to 350 °C under gas phase with a pressure up to 50 bars. This reactor remains nanoparticles of a catalyst homogeneously dispersed in liquid during catalysis and X-ray absorption spectroscopy characterization.

Pressure regulator

DOEpatents

Ebeling, Jr., Robert W.; Weaver, Robert B.

1979-01-01

The pressure within a pressurized flow reactor operated under harsh environmental conditions is controlled by establishing and maintaining a fluidized bed of uniformly sized granular material of selected density by passing the gas from the reactor upwardly therethrough at a rate sufficient to fluidize the bed and varying the height of the bed by adding granular material thereto or removing granular material therefrom to adjust the backpressure on the flow reactor.

Catalytic Tar Reduction for Assistance in Thermal Conversion of Space Waste for Energy Production

NASA Technical Reports Server (NTRS)

Caraccio, Anne Joan; Devor, Robert William; Hintze, Paul E.; Muscatello, Anthony C.; Nur, Mononita

2014-01-01

The Trash to Gas (TtG) project investigates technologies for converting waste generated during spaceflight into various resources. One of these technologies was gasification, which employed a downdraft reactor designed and manufactured at NASA's Kennedy Space Center (KSC) for the conversion of simulated space trash to carbon dioxide. The carbon dioxide would then be converted to methane for propulsion and water for life support systems. A minor byproduct of gasification includes large hydrocarbons, also known as tars. Tars are unwanted byproducts that add contamination to the product stream, clog the reactor and cause complications in analysis instrumentation. The objective of this research was to perform reduction studies of a mock tar using select catalysts and choose the most effective for primary treatment within the KSC downdraft gasification reactor. Because the KSC reactor is operated at temperatures below typical gasification reactors, this study evaluates catalyst performance below recommended catalytic operating temperatures. The tar reduction experimentation was observed by passing a model tar vapor stream over the catalysts at similar conditions to that of the KSC reactor. Reduction in tar was determined using gas chromatography. Tar reduction efficiency and catalyst performances were evaluated at different temperatures.

Hydrodynamics of Packed Bed Reactor in Low Gravity

NASA Technical Reports Server (NTRS)

Motil, Brian J.; Nahra, Henry K.; Balakotaiah, Vemuri

2005-01-01

Packed bed reactors are well known for their vast and diverse applications in the chemical industry; from gas absorption, to stripping, to catalytic conversion. Use of this type of reactor in terrestrial applications has been rather extensive because of its simplicity and relative ease of operation. Developing similar reactors for use in microgravity is critical to many space-based advanced life support systems. However, the hydrodynamics of two-phase flow packed bed reactors in this new environment and the effects of one physiochemical process on another has not been adequately assessed. Surface tension or capillary forces play a much greater role which results in a shifting in flow regime transitions and pressure drop. Results from low gravity experiments related to flow regimes and two-phase pressure drop models are presented in this paper along with a description of plans for a flight experiment on the International Space Station (ISS). Understanding the packed bed hydrodynamics and its effects on mass transfer processes in microgravity is crucial for the design of packed bed chemical or biological reactors to be used for water reclamation and other life support processes involving water purification.

Accumulation of radionuclides in bed sediments of the Columbia River between Hanford reactors and McNary Dam

USGS Publications Warehouse

Nelson, Jack L.; Haushild, W.L.

1970-01-01

Amounts of radionuclides from the Hanford reactors contained in bed sediments of the Columbia River were estimated by two methods: (1) from data on radionuclide concentration for the bed sediments between the reactors and McNary Dam, and (2) from data on radionuclide discharge for river stations at Pasco, Washington, and Umatilla, Oregon. Umatilla is 3.2 kilometers below McNary Dam. Accumulations of radionuclides in the Pasco to Umatilla reach estimated by the two methods agree within about 8%. In October 1965 approximately 16,000 curies of gamma emitting radionuclides were resident in bed sediments of the river between the Hanford reactors and McNary Dam. Concentrations and accumulations of chromium-51, zinc-65, cobalt-60, manganese-54, and scandium-46 generally are much higher near McNary Dam than they are in the vicinity of the reactors. These changes are caused by an increase downstream from the reactors in the proportion of the bed sediment that is fine grained and the proportions of the transported zinc, cobalt, manganese, and scandium radionuclides associated with sediment particles.

Innovative approach for benzene degradation using hybrid surface/packed-bed discharge plasmas.

PubMed

Jiang, Nan; Lu, Na; Shang, Kefeng; Li, Jie; Wu, Yan

2013-09-03

An innovative plasma reactor, which generates hybrid surface/packed-bed discharge (HSPBD) plasmas, was employed for the degradation of benzene. The HSPBD reactor was found to display remarkably better benzene degradation, mineralization, and energy performance than surface or packed-bed discharge reactors alone. The degradation efficiency, CO2 selectivity, and energy yield in the HSPBD reactor were 21%, 11%, and 3.9 g kWh-1 higher, respectively, than in a surface discharge reactor and 30%, 21%, and 5.5 g kWh-1 higher, respectively, than in a packed-bed discharge reactor operated at 280 J L-1. Particularly, the benzene degradation in the HSPBD reactor exhibited an unambiguous synergistic enhancement rather than a simple additive effect using the surface discharge and packed-bed discharge reactors. Moreover, in the HSPBD reactor, the formation of byproducts, such as NO2, was suppressed, while O3 was promoted. The use of N2 as the carrier gas was found to be effective for benzene degradation because of the fast reaction rate of N2(A3∑u+) with benzene, and oxygen species derived from the dissociation of O2 were found to be significant in the mineralization process. Thus, the addition of O2 to N2 allows for efficient degradation of benzene, and the optimized amount of O2 was determined to be 3%.

External Catalyst Breakup Phenomena

DTIC Science & Technology

1976-06-01

catalyst particle can cause high internal pressures which result in particle destruction. Analytical results suggest rhat erosion effects from solid...mechanisms. * Pressure Forces. High G loadings and bed pressure drops should be avoided. Bed pre-loads should be kept at a minimum value. Thruster...5.2.7.1 Failure Theories ............................ 243 5.2.7.2 Maximum Tension Stress Criterion ............ 244 5.2.7.3 Distortion Energy Approach

Why does the Conductivity of a Nickel Catalyst Increase during Sulfidation? An Exemplary Study Using an In Operando Sensor Device.

PubMed

Fremerey, Peter; Jess, Andreas; Moos, Ralf

2015-10-23

In order to study the sulfidation of a catalyst fixed bed, an in operando single pellet sensor was designed. A catalyst pellet from the fixed bed was electrically contacted and its electrical response was correlated with the catalyst behavior. For the sulfidation tests, a nickel catalyst was used and was sulfidized with H₂S. This catalyst had a very low conductivity in the reduced state. During sulfidation, the conductivity of the catalyst increased by decades. A reaction from nickel to nickel sulfide occurred. This conductivity increase by decades during sulfidation had not been expected since both nickel and nickel sulfides behave metallic. Only by assuming a percolation phenomenon that originates from a volume increase of the nickel contacts when reacting to nickel sulfides, this effect can be explained. This assumption was supported by sulfidation tests with differently nickel loaded catalysts and it was quantitatively estimated by a general effective media theory. The single pellet sensor device for in operando investigation of sulfidation can be considered as a valuable tool to get further insights into catalysts under reaction conditions.

Production of carbon nanotubes: Chemical vapor deposition synthesis from liquefied petroleum gas over Fe-Co-Mo tri-metallic catalyst supported on MgO

NASA Astrophysics Data System (ADS)

Setyopratomo, P.; Wulan, Praswasti P. D. K.; Sudibandriyo, M.

2016-06-01

Carbon nanotubes were produced by chemical vapor deposition method to meet the specifications for hydrogen storage. So far, the various catalyst had been studied outlining their activities, performances, and efficiencies. In this work, tri-metallic catalyst consist of Fe-Co-Mo supported on MgO was used. The catalyst was prepared by wet-impregnation method. Liquefied Petroleum Gas (LPG) was used as carbon source. The synthesis was conducted in atmospheric fixed bed reactor at reaction temperature range 750 - 850 °C for 30 minutes. The impregnation method applied in this study successfully deposed metal component on the MgO support surface. It found that the deposited metal components might partially replace Mg(OH)2 or MgO molecules in their crystal lattice. Compare to the original MgO powder; it was significant increases in pore volume and surface area has occurred during catalyst preparation stages. The size of obtained carbon nanotubes is ranging from about 10.83 nm OD/4.09 nm ID up to 21.84 nm OD/6.51 nm ID, which means that multiwall carbon nanotubes were formed during the synthesis. Yield as much as 2.35 g.CNT/g.catalyst was obtained during 30 minutes synthesis and correspond to carbon nanotubes growth rate of 0.2 μm/min. The BET surface area of the obtained carbon nanotubes is 181.13 m2/g and around 50 % of which is contributed by mesopores. Micropore with half pore width less than 1 nm contribute about 10% volume of total micro and mesopores volume of the carbon nanotubes. The existence of these micropores is very important to increase the hydrogen storage capacity of the carbon nanotubes.

Coke Accumulation on Catalysts used in a Fluidized Bed Pyrolyzer

USDA-ARS?s Scientific Manuscript database

We have examined the impact of various solid catalysts on the product distribution resulting from the pyrolysis of biomass. Though catalysts do have a discernible impact, this impact is small. In our bench-top pyrolyzer designed as a catalyst screening tool, we measure bulk product distribution as...

40 CFR 57.302 - Performance level of interim constant controls.

Code of Federal Regulations, 2010 CFR

2010-07-01

... limitation shall take into account unavoidable catalyst deterioration in sulfuric acid plants, but may prescribe the frequency of catalyst screening or replacement. The NSO shall also prohibit the smelter owner... completely fill all available catalyst bed stages with sufficient catalyst; (iii) Inability of the gas pre...

Multifaceted effects of HZSM-5 (Proton-exchanged Zeolite Socony Mobil-5) on catalytic cracking of pinewood pyrolysis vapor in a two-stage fixed bed reactor.

PubMed

Wang, Yimeng; Wang, Jie

2016-08-01

The pinewood was pyrolyzed in the first reactor at a heating rate of 10°Cmin(-1) from room temperature to 700°C, and the vapor was allowed to be cracked through the second reactor in a temperature range of 450-750°C without and with HZSM-5. Attempts were made to determine a wide spectrum of gaseous and liquid products, as well as the mass and element partitions to gas, water, bio-oil, coke and char. HZSM-5 showed a preferential deoxygenation effect via the facilitated decarbonylation and decarboxylation with the inhibited dehydration at 550-600°C. This catalyst also displayed a high selectivity for the formations of aromatic hydrocarbons and olefins by the promoted hydrogen transfer to these products at 550-600°C. The bio-oil produced with HZSM-5 at 500-600°C had the yields of 14.5-16.8%, the high heat values of 39.1-42.4MJkg(-1), and the energy recoveries of 33-35% (all dry biomass basis). Copyright © 2016 Elsevier Ltd. All rights reserved.

Method of performing sugar dehydration and catalyst treatment

DOEpatents

Hu, Jianli [Kennewick, WA; Holladay, Johnathan E [Kennewick, WA; Zhang, Xinjie [Burlington, MA; Wang, Yong [Richland, WA

2010-06-01

The invention includes a method of treating a solid acid catalyst. After exposing the catalyst to a mixture containing a sugar alcohol, the catalyst is washed with an organic solvent and is then exposed to a second reaction mixture. The invention includes a process for production of anhydrosugar alcohol. A solid acid catalyst is provided to convert sugar alcohol in a first sample to an anhydrosugar alcohol. The catalyst is then washed with an organic solvent and is subsequently utilized to expose a second sample. The invention includes a method for selective production of an anhydrosugar. A solid acid catalyst is provided within a reactor and anhydrosugar alcohol is formed by flowing a starting sugar alcohol into the reactor. The acid catalyst is then exposed to an organic solvent which allows a greater amount of additional anhydrosugar to be produced than would occur without exposing the acid catalyst to the organic solvent.

PdCo nanoparticles supported on carbon fibers derived from cotton: Maximum utilization of Pd atoms for efficient reduction of nitroarenes.

PubMed

Yang, Jin; Wang, Wei David; Dong, Zhengping

2018-08-15

In the present work, a facile and environment-friendly route is illustrated for the efficient fabrication of highly dispersed PdCo nanoparticles (NPs) by modified cotton-derived carbon fibers (PdCo/CCF). Firstly, commercial cotton was impregnated with CoCl 2 , followed by pyrolysis under high calcination temperature to obtain the Co NPs modified CCF sample (Co/CCF). Secondly, Co/CCF was treated with Pd(AcO) 2 aqueous solution, wherein, through a spontaneous replacement reaction process, Pd 2+ is reduced to metallic Pd and mostly covered on the surface of the Co NPs. Thus, the PdCo/CCF catalyst was obtained avoiding the use of toxic reductants like NaBH 4 , NH 2 NH 2 and HCHO. The PdCo/CCF catalyst exhibits excellent catalytic activity and recyclability for the reduction of 4-nitrophenol and other nitroarenes compared with Pd/CCF, PdCo NPs and many other noble metals based catalysts. The reasons could be attributed to the uniformly dispersed and accessible PdCo NPs on the surface of the CCF, and the Pd atoms deposited on the Co NPs surface that makes the Pd active sites available for optimum use. The PdCo/CCF catalyst also exhibits potential application for catalytic reduction of nitroarenes in a fixed bed reactor under mild reaction conditions. Furthermore, the PdCo/CCF catalyst can be magnetically recycled and reused for at least ten cycles without either losing catalytic activity or leaching of Pd active sites, thereby confirming its superior stability. Copyright © 2018 Elsevier Inc. All rights reserved.

Thermal Hydraulic Analysis of a Packed Bed Reactor Fuel Element

DTIC Science & Technology

1989-05-25

Engineer and Master of Science in Nuclear Engineering. ABSTRACT A model of the behavior of a packed bed nuclear reactor fuel element is developed . It...RECOMMENDATIONS FOR FURTHER INVESTIGATION .................... 150 APPENDIX A FUEL ELEMENT MODEL PROGRAM DESIGN AND OPERA- T IO N...follow describe the details of the packed bed reactor and then discuss the development of the mathematical representations of the fuel element. These are

Catalytic biofilms on structured packing for the production of glycolic acid.

PubMed

Li, Xuan Zhong; Hauer, Bernhard; Rosche, Bettina

2013-02-01

While structured packing modules are known to be efficient for surface wetting and gas-liquid exchange in abiotic surface catalysis, this model study explores structured packing as a growth surface for catalytic biofilms. Microbial biofilms have been proposed as self-immobilized and self-regenerating catalysts for the production of chemicals. A concern is that the complex and dynamic nature of biofilms may cause fluctuations in their catalytic performance over time or may affect process reproducibility. An aerated continuous trickle-bed biofilm reactor system was designed with a 3 L structured packing, liquid recycling and pH control. Pseudomonas diminuta established a biofilm on the stainless steel structured packing with a specific surface area of 500 m2 m-3 and catalyzed the oxidation of ethylene glycol to glycolic acid for over two months of continuous operation. A steady-state productivity of up to 1.6 gl-1h-1 was achieved at a dilution rate of 0.33 h-1. Process reproducibility between three independent runs was excellent, despite process interruptions and activity variations in cultures grown from biofilm effluent cells. The results demonstrate the robustness of a catalytic biofilm on structured packing, despite its dynamic nature. Implementation is recommended for whole-cell processes that require efficient gas-liquid exchange, catalyst retention for continuous operation, or improved catalyst stability.

NEUTRONIC REACTOR POWER PLANT

DOEpatents

Metcalf, H.E.

1962-12-25

This patent relates to a nuclear reactor power plant incorporating an air-cooled, beryllium oxide-moderated, pebble bed reactor. According to the invention means are provided for circulating a flow of air through tubes in the reactor to a turbine and for directing a sidestream of the circu1ating air through the pebble bed to remove fission products therefrom as well as assist in cooling the reactor. (AEC)

Catalytic membrane reactor for water and wastewater treatment

NASA Astrophysics Data System (ADS)

Heng, Samuel

A double membrane reactor was fabricated and assessed for continuous treatment of water containing organic contaminants by ozonation. This innovative reactor consisted of a zeolite membrane prepared on the inner surface of a porous a-alumina support, which served as water selective extractor and active contactor, and a porous stainless membrane which was the ozone gas diffuser. The coupling of membrane separation and chemical oxidation was found to be highly beneficial to both processes. The total organic carbon (TOC) removal rate at the retentate was enhanced by up to 2.2 times, as compared to membrane ozonation. Simultaneously, clean water (< 2 mg C.L-1 ) was consistently produced on the permeate side, using a feed solution containing up to 1000 mg C.L-1, while the retentate was concentrated and treated. Most significantly, the addition of an adsorbing material, as a bed or a coated layer, onto the pores of the membrane support, was shown to further enhance TOC degradation, permeated TOC concentration, permeate flux, and moreover, ozone yield. The achievements of this project included: (1) The development of a novel low-temperature zeolite membrane activation method that generates consistently high quality membranes (i.e. high reproducibility and fewer defects). (2) The demonstration that gamma-alumina and gamma-alumina supported catalysts do not have significant activity and that the TOC removal enhancement usually observed during catalytic ozonation was due primarily to the contribution of adsorption and metal leaching. Thermogravimetric analysis (TGA) and elemental analysis (EA) of the spent catalyst showed that, during catalytic ozonation, oxygenated by-products of increased adsorbability were concentrated onto the gamma-alumina contactor, and were subsequently degraded. (3) The development of a method for coating high surface area gamma-alumina layers onto the grains of zeolite membrane support used as the active membrane contactor.

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

During this time period, at WVU, the authors have obtained models for the kinetics of the HAS (higher alcohol synthesis) reaction over the Co-K-MoS{sub 2}/C catalyst. The Rotoberty reactor was then replaced in the reactor system by a plug-flow tubular reactor. Accordingly, the authors re-started the investigations on sulfide catalysts. The authors encountered and solved the leak problem from the sampling valve for the non-sulfided reactor system. They also modified the system to eliminate the condensation problem. Accordingly, they are continuing their kinetic studies on the reduced Mo-Ni-K/C catalysts. They have set up an apparatus for temperature-programmed reduction (TPR) studies,more » and have obtained some interesting results on TPR characterizations. At UCC, the complete characterization of selected catalysts has been started. The authors sent nine selected types of ZnO, Zn/CrO and Zn/Cr/MnO catalysts and supports for BET surface area, SEM, XRD and ICP. They also sent fresh and spent samples of the Engelhard Zn/CrO catalyst impregnated with 3 wt% potassium for ISS and XPS testing. In Task 2, work on the design and optimization portion of this task, as well as on the fuel testing, is completed. All funds have been expended and there are no personnel working on this project.« less

Catalytic decomposition of toxic chemicals over metal-promoted carbon nanotubes.

PubMed

Li, Lili; Han, Changxiu; Han, Xinyu; Zhou, Yixiao; Yang, Li; Zhang, Baogui; Hu, Jianli

2011-01-15

Effective decomposition of toxic gaseous compounds is important for pollution control at many chemical manufacturing plants. This study explores catalytic decomposition of phosphine (PH(3)) using novel metal-promoted carbon nanotubes (CNTs). The cerium-promoted Co/CNTs catalysts (CoCe/CNTs) are synthesized by means of coimpregnation method and reduced by three different methods (H(2), KBH(4), NaH(2)PO(2)·H(2)O/KBH(4)). The morphology, structure, and composition of the catalysts are characterized using a number of analytical instrumentations including high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, BET surface area measurement, and inductively coupled plasma. The activity of the catalysts in PH(3) decomposition reaction is measured and correlated with their surface and structural properties. The characterization results show that the CoCe/CNTs catalyst reduced by H(2) possesses small particles and is shown thermally stable in PH(3) decomposition reaction. The activities of these catalysts are compared and are shown in the following sequence: CoCe/CNTs > Co/CNTs > CoCeBP/CNTs> CoCeB/CNTs. The difference in reduction method results in the formation of different active phases during the PH(3) decomposition reaction. After a catalytic activity test, only the CoP phase is formed on CoCe/CNTs and Co/CNTs catalysts, whereas multiphases CoP, Co(2)P, and Co phases are formed on CoCeBP/CNTs and CoCeB/CNTs. Results show that the CoP phase is formed predominantly on the CoCe/CNTs and Co/CNTs catalysts and is found to likely be the most active phase for this reaction. Furthermore, the CoCe/CNTs catalyst exhibits not only highest activity but also long-term stability in PH(3) decomposition reaction. When operated in a fixed-bed reactor at 360 °C, single-pass PH(3) conversion of about 99.8% can be achieved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The objective of Task 1 is to prepare and evaluate catalysts and to develop efficient reactor systems for the selective conversion of hydrogen-lean synthesis gas to alcohol fuel extender and octane enhancers. Task 1 is subdivided into three separate subtasks: laboratory and equipment setup; catalysis research; and reaction engineering and modeling. Research at West Virginia University (WVU) is focused on molybdenum-based catalysts for higher alcohol synthesis. Parallel research carried out at Union Carbide Corporation (UCC) is focused on transition-metal-oxide catalysts. During this time period, at WVU, we tried several methods to eliminate problems related to condensation of heavier products whenmore » reduced Mo-Ni-K/C materials were used as catalysts. We then resumed our kinetic study on the reduced Mo-Ni-K/C materials were used as catalysts. We then resumed our kinetic study on the reduced Mo-Ni-K/C catalysts. We have also obtained same preliminary results in our attempts to analyze quantitatively the temperature-programmed reduction spectra for C- supported Mo-based catalysts. We have completed the kinetic study for the sulfided Co-K-MoS{sub 2}/C catalyst. We have compared the results of methanol synthesis using the membrane reactor with those using a simple plug-flow reactor. At UCC, the complete characterization of selected catalysts has been completed. The results suggest that catalyst pretreatment under different reducing conditions yield different surface compositions and thus different catalytic reactivities.« less

Feasibility Study of the Geotextile Waste Filtration Unit.

DTIC Science & Technology

2000-02-10

Treatment Module 3-32 Figure 3-20. THE SCHEMATIC OF THE MOVING BED BIOFILM REACTOR ( MBBR ) 3൪ Figure 4-1. The Original Distributed Concept for WFUs...Moving Bed Biofilm Reactor ( MBBR ) process appears to be one of the most feasible processes available to meet Force Provider liquid waste stream...Moving Bed Biofilm Reactor ( MBBR ) process was then examined.31 In this system, both activated sludge and fixed-film processes occur in a bioreactor

Factors affecting cleanup of exhaust gases from a pressurized, fluidized-bed coal combustor

NASA Technical Reports Server (NTRS)

Rollbuhler, R. J.; Kobak, J. A.

1980-01-01

The cleanup of effluent gases from the fluidized-bed combustion of coal is examined. Testing conditions include the type and feed rate of the coal and the sulfur sorbent, the coal-sorbent ratio, the coal-combustion air ratio, the depth of the reactor fluidizing bed, and the technique used to physically remove fly ash from the reactor effluent gases. Tests reveal that the particulate loading matter in the effluent gases is a function not only of the reactor-bed surface gas velocity, but also of the type of coal being burnt and the time the bed is operating. At least 95 percent of the fly ash particules in the effluent gas are removed by using a gas-solids separator under controlled operating conditions. Gaseous pollutants in the effluent (nitrogen and sulfur oxides) are held within the proposed Federal limits by controlling the reactor operating conditions and the type and quantity of sorbent material.

Flow instability in particle-bed nuclear reactors

NASA Technical Reports Server (NTRS)

Kerrebrock, J. L.; Kalamas, J.

1993-01-01

A three-dimensional model of the stability of the particle-bed reactor is presented, in which the fluid has mobility in three dimensions. The model accurately represents the stability at low Re numbers as well as the effects of the cold and hot frits and of the heat conduction and radiation in the particle bed. The model can be easily extended to apply to the cylindrical geometry of particle-bed reactors. Exemplary calculations are carried out, showing that a particle bed without a cold frit would be subject to instability if operated at the high-temperature ratios used for nuclear rockets and at power densities below about 4 MW/l; since the desired power density for such a reactor is about 40 MW/l, the operation at design exit temperature but at reduced power could be hazardous. Calculations show however that it might be possible to remove the instability problem by appropriate combinations of cold and hot frits.

Safety apparatus for nuclear reactor to prevent structural damage from overheating by core debris

DOEpatents

Gabor, John D.; Cassulo, John C.; Pedersen, Dean R.; Baker, Jr., Louis

1986-01-01

The invention teaches safety apparatus that can be included in a nuclear reactor, either when newly fabricated or as a retrofit add-on, that will minimize proliferation of structural damage to the reactor in the event the reactor is experiencing an overheating malfunction whereby radioactive nuclear debris might break away from and be discharged from the reactor core. The invention provides a porous bed or sublayer on the lower surface of the reactor containment vessel so that the debris falls on and piles up on the bed. Vapor release elements upstand from the bed in some laterally spaced array. Thus should the high heat flux of the debris interior vaporize the coolant at that location, the vaporized coolant can be vented downwardly to and laterally through the bed to the vapor release elements and in turn via the release elements upwardly through the debris. This minimizes the pressure buildup in the debris and allows for continuing infiltration of the liquid coolant into the debris interior.

Safety apparatus for nuclear reactor to prevent structural damage from overheating by core debris

DOEpatents

Gabor, John D.; Cassulo, John C.; Pedersen, Dean R.; Baker Jr., Louis

1986-07-01

The invention teaches safety apparatus that can be included in a nuclear reactor, either when newly fabricated or as a retrofit add-on, that will minimize proliferation of structural damage to the reactor in the event the reactor is experiencing an overheating malfunction whereby radioactive nuclear debris might break away from and be discharged from the reactor core. The invention provides a porous bed or sublayer on the lower surface of the reactor containment vessel so that the debris falls on and piles up on the bed. Vapor release elements upstand from the bed in some laterally spaced array. Thus should the high heat flux of the debris interior vaporize the coolant at that location, the vaporized coolant can be vented downwardly to and laterally through the bed to the vapor release elements and in turn via the release elements upwardly through the debris. This minimizes the pressure buildup in the debris and allows for continuing infiltration of the liquid coolant into the debris interior.

Safety apparatus for nuclear reactor to prevent structural damage from overheating by core debris

DOEpatents

Gabor, J.D.; Cassulo, J.C.; Pedersen, D.R.; Baker, L. Jr.

The invention teaches safety apparatus that can be included in a nuclear reactor, either when newly fabricated or as a retrofit add-on, that will minimize proliferation of structural damage to the reactor in the event the reactor is experiencing an overheating malfunction whereby radioactive nuclear debris might break away from and can be discharged from the reactor core. The invention provides a porous bed of sublayer on the lower surface of the reactor containment vessel so that the debris falls on and piles up on the bed. Vapor release elements upstand from the bed in some laterally spaced array. Thus should the high heat flux of the debris interior vaporize the coolant at that location, the vaporized coolant can be vented downwardly to and laterally through the bed to the vapor release elements and in turn via the release elements upwardly through the debris. This minimizes the pressure buildup in the debris and allows for continuing infiltration of the liquid coolant into the debris interior.

An efficient TiO2 coated immobilized system for the degradation studies of herbicide isoproturon: durability studies.

PubMed

Verma, A; Prakash, N T; Toor, A P

2014-08-01

The investigation presents the observations on the use of cement beads for the immobilization of TiO2 for the degradation of herbicide isoproturon. The immobilized system was effective in degrading and mineralizing the herbicide for continuous thirty cycles without losing its durability. Catalyst was characterized by SEM-EDAX for checking the durability of the catalyst. The degradation rate followed first order kinetics as measured by change in absorption intensity in UV range as well as HPLC analysis. Two rounds of TiO2 coating on inert cement beads with average diameter 1.5cm at UV Intensity 25Wm(-2) calcined at 400°C were the optimized conditions for the degradation of herbicide isoproturon. More than 90% TOC and COD reduction along with ammonium ions generation (80%) confirmed the mineralization of isoproturon. Fixed bed baffled reactor studies under solar irradiations using the TiO2 immobilized beads confirmed 85% degradation after 6h. LC-MS studies confirmed the intermediates formation and their subsequent degradation using immobilized system. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of torrefaction pretreatment and catalytic pyrolysis on the pyrolysis poly-generation of pine wood.

PubMed

Chen, Dengyu; Li, Yanjun; Deng, Minsi; Wang, Jiayang; Chen, Miao; Yan, Bei; Yuan, Qiqiang

2016-08-01

Torrefaction of pine wood was performed in a tube furnace at three temperatures (220, 250, and 280°C) for 30min. Then catalytic pyrolysis of raw and torrefied pine wood was performed using HZSM-5 catalyst in a fixed-bed pyrolysis reactor at 550°C for 15min. Torrefaction pretreatment and catalytic pyrolysis have an very important effect on the yield, property, and energy distribution of pyrolysis products. The results showed that the yield of biochar rapidly increased, while that of bio-oil decreased with increasing torrefaction temperature. The oxy-compound content of bio-oil, such as acids and aldehydes, sharply decreased. However, the aromatic hydrocarbon content not only increased but also further promoted by HZSM-5 catalyst. With highest mass yields and energy yields, biochar was also the very important product of pyrolysis. The oxygen content in biomass was mainly removed in the form of CO2 and H2O, leading to increasing CO2 content in non-condensable gas. Copyright © 2016 Elsevier Ltd. All rights reserved.

Methods of making alkyl esters

DOEpatents

Elliott, Brian

2010-08-03

A method comprising contacting an alcohol, a feed comprising one or more glycerides and equal to or greater than 2 wt % of one or more free fatty acids, and a solid acid catalyst, a nanostructured polymer catalyst, or a sulfated zirconia catalyst in one or more reactors, and recovering from the one or more reactors an effluent comprising equal to or greater than about 75 wt % alkyl ester and equal to or less than about 5 wt % glyceride.

Catalytic converter with fluid injector for catalyst-free enclosure of catalyst bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrew, S.P.S.

1984-09-25

A fluid injection lozenge comprises two tubes supporting a perforate member forming a cage enclosing the space between the tubes. Each tube has a series of perforations along its length so that a fluid can be injected, through the tube, into the enclosed space. The lozenges are of use in catalytic converters of either the axial or radial flow design. In the case of a radial flow converter, a plurality of tubes are provided, preferably connected in pairs by the perforate members, to form a squirrel cage structure, disposed in the catalyst bed.

Radiation absorption and optimization of solar photocatalytic reactors for environmental applications.

PubMed

Colina-Márquez, Jose; Machuca-Martínez, Fiderman; Li Puma, Gianluca

2010-07-01

This study provides a systematic and quantitative approach to the analysis and optimization of solar photocatalytic reactors utilized in environmental applications such as pollutant remediation and conversion of biomass (waste) to hydrogen. Ray tracing technique was coupled with the six-flux absorption scattering model (SFM) to analyze the complex radiation field in solar compound parabolic collectors (CPC) and tubular photoreactors. The absorption of solar radiation represented by the spatial distribution of the local volumetric rate of photon absorption (LVRPA) depends strongly on catalyst loading and geometry. The total radiation absorbed in the reactors, the volumetric rate of absorption (VRPA), was analyzed as a function of the optical properties (scattering albedo) of the photocatalyst. The VRPA reached maxima at specific catalyst concentrations in close agreement with literature experimental studies. The CPC has on average 70% higher photon absorption efficiency than a tubular reactor and requires 39% less catalyst to operate under optimum conditions. The "apparent optical thickness" is proposed as a new dimensionless parameter for optimization of CPC and tubular reactors. It removes the dependence of the optimum catalyst concentration on tube diameter and photocatalyst scattering albedo. For titanium dioxide (TiO(2)) Degussa P25, maximum photon absorption occurs at apparent optical thicknesses of 7.78 for CPC and 12.97 for tubular reactors.

Chemical Processing in High-Pressure Aqueous Environments. 9. Process Development for Catalytic Gasification of Algae Feedstocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, Douglas C.; Hart, Todd R.; Neuenschwander, Gary G.

Through the use of a metal catalyst, gasification of wet algae slurries can be accomplished with high levels of carbon conversion to gas at relatively low temperature (350 C). In a pressurized-water environment (20 MPa), near-total conversion of the organic structure of the algae to gases has been achieved in the presence of a supported ruthenium metal catalyst. The process is essentially steam reforming, as there is no added oxidizer or reagent other than water. In addition, the gas produced is a medium-heating value gas due to the synthesis of high levels of methane, as dictated by thermodynamic equilibrium. Asmore » opposed to earlier work, biomass trace components were removed by processing steps so that they did not cause processing difficulties in the fixed catalyst bed tubular reactor system. As a result, the algae feedstocks, even those with high ash contents, were much more reliably processed. High conversions were obtained even with high slurry concentrations. Consistent catalyst operation in these short-term tests suggested good stability and minimal poisoning effects. High methane content in the product gas was noted with significant carbon dioxide captured in the aqueous byproduct in combination with alkali constituents and the ammonia byproduct derived from proteins in the algae. High conversion of algae to gas products was found with low levels of byproduct water contamination and low to moderate loss of carbon in the mineral separation step.« less

Syngas Production from CO2 Reforming and CO2-steam Reforming of Methane over Ni/Ce-SBA-15 Catalyst

NASA Astrophysics Data System (ADS)

Tan, J. S.; Danh, H. T.; Singh, S.; Truong, Q. D.; Setiabudi, H. D.; Vo, D.-V. N.

2017-06-01

This study compares the catalytic performance of mesoporous 10 Ni/Ce-SBA-15 catalyst for CO2 reforming and CO2-steam reforming of methane reactions in syngas production. The catalytic performance of 10 Ni/Ce-SBA-15 catalyst for CO2 reforming and CO2-steam reforming of methane was evaluated in a temperature-controlled tubular fixed-bed reactor at stoichiometric feed composition, 1023 K and atmospheric pressure for 12 h on-stream with gas hourly space velocity (GHSV) of 36 L gcat -1 h-1. The 10 Ni/Ce-SBA-15 catalyst possessed a high specific BET surface area and average pore volume of 595.04 m2 g-1. The XRD measurement revealed the presence of NiO phase with crystallite dimension of about 13.60 nm whilst H2-TPR result indicates that NiO phase was completely reduced to metallic Ni0 phase at temperature beyond 800 K and the reduction temperature relied on different degrees of metal-support interaction associated with the location and size of NiO particles. The catalytic reactivity was significantly enhanced with increasing H2O/CO2 feed ratio. Interestingly, the H2/CO ratio for CO2-steam reforming of methane varied between 1 and 3 indicated the occurrence of parallel reactions, i.e., CH4 steam reforming giving a H2/CO of 3 whilst reverse water-gas shift (RWGS) reaction consuming H2 to produce CO gaseous product.

Method of realizing catalytic processes under unsteady state conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noskov, A.S.; Lakhmostov, V.S.; Matros, Yu.S.

1988-07-01

The operation of a system with the catalyst bed divided into three parts was investigated theoretically and experimentally. The conditions under which the system will efficiently convert a reaction mixture with a low inlet temperature in an unsteady state regime are determined. Calculations were performed for the industrially typical process of afterburning CO on a copper-chrome catalyst in the form of Raschig rings. A flow sheet of the unit with the catalyst divided into three is shown with temperature profiles along the bed at various moments in time. The method can be used for processing large volumes of gaseous wastesmore » on very active catalysts and for catalytic reactions with optimum temperature profiles close to those presented.« less

Alkylation of organic aromatic compounds

DOEpatents

Smith, L.A. Jr.

1989-07-18

Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

Alkylation of organic aromatic compounds

DOEpatents

Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

1994-01-01

Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

Alkylation of organic aromatic compounds

DOEpatents

Smith, Jr., Lawrence A.

1989-01-01

Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

Alkylation of organic aromatic compounds

DOEpatents

Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

1994-06-14

Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a molecular sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

Enzymatic production of monoacylglycerols containing polyunsaturated fatty acids through an efficient glycerolysis system.

PubMed

Yang, Tiankui; Rebsdorf, Morten; Engelrud, Ulrik; Xu, Xuebing

2005-03-09

The aim of the study was to develop an efficient glycerolysis system for the enzymatic production of monoacylglycerols (MAGs) containing polyunsaturated fatty acids. Glycerolysis has been widely applied in industry for the chemical production of food MAGs under high temperature. The enzymatic glycerolysis system at 40-70 degrees C is unfortunately a multiphase system, which leads to the lower reaction efficiency. A tert-butyl alcohol system was developed after careful evaluation and more than 20-fold of the reaction efficiency from this system was obtained compared to the solvent-free system. Novozym 435 was employed as a catalyst in the glycerolysis from the screening. In the batch reaction system with tert-butyl alcohol, temperature higher than 40 degrees C was favored. The glycerol/oil ratio was best in the study with 4.5 while the solvent weight ratio from 1 to 3 had little effect. In general, 60-70% yield can be obtained at 2 h in the stirred tank reactor. The continuous glycerolysis was conducted in a packed bed reactor. MAG yield up to 70% was reached at 30-40 min residence time. The continuous glycerolysis was more sensitive to the amount of tert-butyl alcohol, and in the weight ratio to oil more than 2 was favored. The continuous process was optimized with the assistance of response surface methodology. Optimal conditions for the packed bed reactor after all considerations were recommended as glycerol/oil 4:1 (mol/mol), temperature 40 degrees C, and residence time 45 min. The operation stability study showed that there was no slight reduction of reaction performance at more than 30 days, implying a high feasibility in practical applications.

Series-Bosch Technology for Oxygen Recovery During Lunar or Martian Surface Missions

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Mansell, J. Matthew; Rabenberg, Ellen; Stanley, Christine M.; Edmunson, Jennifer; Alleman, James E.; Chen, Kevin; Dumez, Sam

2014-01-01

Long-duration surface missions to the Moon or Mars will require life support systems that maximize resource recovery to minimize resupply from Earth. To address this need, NASA previously proposed a Series-Bosch (S-Bosch) oxygen recovery system, based on the Bosch process, which can theoretically recover 100% of the oxygen from metabolic carbon dioxide. Bosch processes have the added benefits of the potential to recover oxygen from atmospheric carbon dioxide and the use of regolith materials as catalysts, thereby eliminating the need for catalyst resupply from Earth. In 2012, NASA completed an initial design for an S-Bosch development test stand that incorporates two catalytic reactors in series including a Reverse Water-Gas Shift (RWGS) Reactor and a Carbon Formation Reactor (CFR). In 2013, fabrication of system components, with the exception of a CFR, and assembly of the test stand was initiated. Stand-alone testing of the RWGS reactor was completed to compare performance with design models. Continued testing of Lunar and Martian regolith simulants provided sufficient data to design a CFR intended to utilize these materials as catalysts. Finally, a study was conducted to explore the possibility of producing bricks from spent regolith catalysts. The results of initial demonstration testing of the RWGS reactor, results of continued catalyst performance testing of regolith simulants, and results of brick material properties testing are reported. Additionally, design considerations for a regolith-based CFR are discussed.

Series-Bosch Technology for Oxygen Recovery During Lunar or Martian Surface Missions

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Mansell, James M.; Stanley, Christine; Edmunson, Jennifer; Dumez, Samuel; Chen, Kevin; Alleman, James E.

2014-01-01

Long-duration surface missions to the Moon or Mars will require life support systems that maximize resource recovery to minimize resupply from Earth. To address this need, NASA previously proposed a Series-Bosch (S-Bosch) oxygen recovery system, based on the Bosch process, which can theoretically recover 100% of the oxygen from metabolic carbon dioxide. Bosch processes have the added benefits of the potential to recover oxygen from atmospheric carbon dioxide and the use of regolith materials as catalysts, thereby eliminating the need for catalyst resupply from Earth. In 2012, NASA completed an initial design for an S-Bosch development test stand that incorporates two catalytic reactors in series including a Reverse Water-Gas Shift (RWGS) Reactor and a Carbon Formation Reactor (CFR). In 2013, fabrication of system components, with the exception of a CFR, and assembly of the test stand was initiated. Stand-alone testing of the RWGS reactor was completed to compare performance with design models. Continued testing of Lunar and Martian regolith simulants provided sufficient data to design a CFR intended to utilize these materials as catalysts. Finally, a study was conducted to explore the possibility of producing bricks from spend regolith catalysts. The results of initial demonstration testing of the RWGS reactor, results of continued catalyst performance testing of regolith simulants, and results of brick material properties testing are reported. Additionally, design considerations for a regolith-based CFR are discussed.

Flow instability in particle-bed nuclear reactors

NASA Astrophysics Data System (ADS)

Kerrebrock, Jack L.

The particle-bed core offers mitigation of some of the problems of solid-core nuclear rocket reactors. Dividing the fuel elements into small spherical particles contained in a cylindrical bed through which the propellant flows radially, may reduce the thermal stress in the fuel elements, allowing higher propellant temperatures to be reached. The high temperature regions of the reactor are confined to the interior of cylindrical fuel assemblies, so most of the reactor can be relatively cool. This enables the use of structural and moderating materials which reduce the minimum critical size and mass of the reactor. One of the unresolved questions about this concept is whether the flow through the particle-bed will be well behaved, or will be subject to destructive flow instabilities. Most of the recent analyses of the stability of the particle-bed reactor have been extensions of the approach of Bussard and Delauer, where the bed is essentially treated as an array of parallel passages, so that the mass flow is continuous from inlet to outlet through any one passage. A more general three dimensional model of the bed is adopted, in which the fluid has mobility in three dimensions. Comparison of results of the earlier approach to the present one shows that the former does not accurately represent the stability at low Re. The more complete model presented should be capable of meeting this deficiency while accurately representing the effects of the cold and hot frits, and of heat conduction and radiation in the particle-bed. It can be extended to apply to the cylindrical geometry of particle-bed reactors without difficulty. From the exemplary calculations which were carried out, it can be concluded that a particle-bed without a cold frit would be subject to instability if operated at the high temperatures desired for nuclear rockets, and at power densities below about 4 megawatts per liter. Since the desired power density is about 40 megawatts per liter, it can be concluded that operation at design exit temperature but at reduced power could be hazardous for such a reactor. But the calculations also show that an appropriate cold frit could very likely cure the instability. More definite conclusions must await calculations for specific designs.

Flow instability in particle-bed nuclear reactors

NASA Technical Reports Server (NTRS)

Kerrebrock, Jack L.

1993-01-01

The particle-bed core offers mitigation of some of the problems of solid-core nuclear rocket reactors. Dividing the fuel elements into small spherical particles contained in a cylindrical bed through which the propellant flows radially, may reduce the thermal stress in the fuel elements, allowing higher propellant temperatures to be reached. The high temperature regions of the reactor are confined to the interior of cylindrical fuel assemblies, so most of the reactor can be relatively cool. This enables the use of structural and moderating materials which reduce the minimum critical size and mass of the reactor. One of the unresolved questions about this concept is whether the flow through the particle-bed will be well behaved, or will be subject to destructive flow instabilities. Most of the recent analyses of the stability of the particle-bed reactor have been extensions of the approach of Bussard and Delauer, where the bed is essentially treated as an array of parallel passages, so that the mass flow is continuous from inlet to outlet through any one passage. A more general three dimensional model of the bed is adopted, in which the fluid has mobility in three dimensions. Comparison of results of the earlier approach to the present one shows that the former does not accurately represent the stability at low Re. The more complete model presented should be capable of meeting this deficiency while accurately representing the effects of the cold and hot frits, and of heat conduction and radiation in the particle-bed. It can be extended to apply to the cylindrical geometry of particle-bed reactors without difficulty. From the exemplary calculations which were carried out, it can be concluded that a particle-bed without a cold frit would be subject to instability if operated at the high temperatures desired for nuclear rockets, and at power densities below about 4 megawatts per liter. Since the desired power density is about 40 megawatts per liter, it can be concluded that operation at design exit temperature but at reduced power could be hazardous for such a reactor. But the calculations also show that an appropriate cold frit could very likely cure the instability. More definite conclusions must await calculations for specific designs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

During this reporting period, there were three major thrusts in the WVU portion. First, we started a preliminary investigation on the use of a membrane reactor for HAS. Accordingly, the plug-flow reactor which had been isolated from sulfides was substituted by a membrane reactor. The tubular membrane was first characterized in terms of its permeation properties, i.e., the fluxes, permeances and selectivities of the components. After that, a BASF methanol-synthesis catalyst was tested under different conditions on the membrane reactor. The results will be compared with those from a non-permeable stainless steel tubular reactor under the same conditions. Second, wemore » started a detailed study of one of the catalysts tested during the screening runs. Accordingly, a carbon-supported potassium-doped molybdenum-cobalt catalyst was selected to be run in the Rotoberty reactor. Finally, we have started detailed analyses of reaction products from some earlier screening runs in which non-sulfide molybdenum-based catalysts were employed and much more complicated product distributions were generally observed. These products could not hitherto be analyzed using the gas chromatograph which was then available. A Varian gas chromatograph/mass spectrometer (GC/MS) is being used to characterize these liquid products. At UCC, we completed a screening of an Engelhard support impregnated with copper and cesium. We have met or exceeded three of four catalyst development targets. Oxygenate selectivity is our main hurdle. Further, we tested the effect of replacing stainless-steel reactor preheater tubing and fittings with titanium ones. We had hoped to reduce the yield of hydrocarbons which may have been produced at high temperatures due to Fischer-Tropsch catalysis with the iron and nickel in the preheater tube walls. Results showed that total hydrocarbon space time yield was actually increased with the titanium preheater, while total alcohol space time yield was not significantly affected.« less

Why does the Conductivity of a Nickel Catalyst Increase during Sulfidation? An Exemplary Study Using an In Operando Sensor Device

PubMed Central

Fremerey, Peter; Jess, Andreas; Moos, Ralf

2015-01-01

In order to study the sulfidation of a catalyst fixed bed, an in operando single pellet sensor was designed. A catalyst pellet from the fixed bed was electrically contacted and its electrical response was correlated with the catalyst behavior. For the sulfidation tests, a nickel catalyst was used and was sulfidized with H2S. This catalyst had a very low conductivity in the reduced state. During sulfidation, the conductivity of the catalyst increased by decades. A reaction from nickel to nickel sulfide occurred. This conductivity increase by decades during sulfidation had not been expected since both nickel and nickel sulfides behave metallic. Only by assuming a percolation phenomenon that originates from a volume increase of the nickel contacts when reacting to nickel sulfides, this effect can be explained. This assumption was supported by sulfidation tests with differently nickel loaded catalysts and it was quantitatively estimated by a general effective media theory. The single pellet sensor device for in operando investigation of sulfidation can be considered as a valuable tool to get further insights into catalysts under reaction conditions. PMID:26512669

Thermal reactor for afterburning automotive internal combustion engine exhaust gases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masaki, K.; Nagaishi, H.

1974-08-08

A thermal reactor for burning unburned components in exhaust gases of an internal combustion engine before emission to the atmosphere is described. An outer casing has an exhaust gas inlet connected to the exhaust ports, and an inner casing divides the reactor into an outer chamber and an inner chamber. The inner casing has an inlet from the outer chamber, an outlet to the atmosphere, and perforations opening to the outer chamber. An oxidation catalyst in the inner chamber promotes oxidation of the unburned components in the exhaust gases to generate oxidation reaction heat. A first secondary air injection nozzlemore » in the inner chamber between the oxidation catalyst and the outlet and a second secondary air injection nozzle in a portion upstream of the oxidation catalyst inject secondary air into oxidation catalyst.« less

Media arrangement impacts cell growth in anaerobic fixed-bed reactors treating sugarcane vinasse: Structured vs. randomic biomass immobilization.

PubMed

de Aquino, Samuel; Fuess, Lucas Tadeu; Pires, Eduardo Cleto

2017-07-01

This study reports on the application of an innovative structured-bed reactor (FVR) as an alternative to conventional packed-bed reactors (PBRs) to treat high-strength solid-rich wastewaters. Using the FVR prevents solids from accumulating within the fixed-bed, while maintaining the advantages of the biomass immobilization. The long-term operation (330days) of a FVR and a PBR applied to sugarcane vinasse under increasing organic loads (2.4-18.0kgCODm -3 day -1 ) was assessed, focusing on the impacts of the different media arrangements over the production and retention of biomass. Much higher organic matter degradation rates, as well as long-term operational stability and high conversion efficiencies (>80%) confirmed that the FVR performed better than the PBR. Despite the equivalent operating conditions, the biomass growth yield was different in both reactors, i.e., 0.095gVSSg -1 COD (FVR) and 0.066gVSSg -1 COD (PBR), indicating a clear control of the media arrangement over the biomass production in fixed-bed reactors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fuel Processing System for a 5kW Methanol Fuel Cell Power Unit.

DTIC Science & Technology

1985-11-27

report documents the development and design of a 5kW neat methanol reformer for phosphoric acid fuel cell power plants . The reformer design was based...VAPORIZATION OF METHANOL ........... 4.3 REFORMING/SHIFT CATALYST BED ......... 2 5.0 COMPONENT TESTING............... 5.1 COMBUSTION TUBE...69 36 Catalyst Bed Temperature Profile Before and After Transient ................. 70 37 Assembly -5kw Neat Methanol Reformer. ......... 72 Page No

Effect of catalyst additives on the production of biofuels from palm oil cracking in a transport riser reactor.

PubMed

Chew, Thiam Leng; Bhatia, Subhash

2009-05-01

Catalytic cracking of crude palm oil (CPO) and used palm oil (UPO) were studied in a transport riser reactor for the production of biofuels at a reaction temperature of 450 degrees C, with residence time of 20s and catalyst-to-oil ratio (CTO) of 5 gg(-1). The effect of HZSM-5 (different Si/Al ratios), beta zeolite, SBA-15 and AlSBA-15 were studied as physically mixed additives with cracking catalyst Rare earth-Y (REY). REY catalyst alone gave 75.8 wt% conversion with 34.5 wt% of gasoline fraction yield using CPO, whereas with UPO, the conversion was 70.9 wt% with gasoline fraction yield of 33.0 wt%. HZSM-5, beta zeolite, SBA-15 and AlSBA-15 as additives with REY increased the conversion and the yield of organic liquid product. The transport riser reactor can be used for the continuous production of biofuels from cracking of CPO and UPO over REY catalyst.

Atmosphere Processing Module Automation and Catalyst Durability Analysis for Mars ISRU Pathfinder

NASA Technical Reports Server (NTRS)

Petersen, Elspeth M.

2016-01-01

The Mars In-Situ Resource Utilization Pathfinder was designed to create fuel using components found in the planet’s atmosphere and regolith for an ascension vehicle to return a potential sample return or crew return vehicle from Mars. The Atmosphere Processing Module (APM), a subunit of the pathfinder, uses cryocoolers to isolate and collect carbon dioxide from Mars simulant gas. The carbon dioxide is fed with hydrogen into a Sabatier reactor where methane is produced. The APM is currently undergoing the final stages of testing at Kennedy Space Center prior to process integration testing with the other subunits of the pathfinder. The automation software for the APM cryocoolers was tested and found to perform nominally. The catalyst used for the Sabatier reactor was investigated to determine the factors contributing to catalyst failure. The results from the catalyst testing require further analysis, but it appears that the rapid change in temperature during reactor start up or the elevated operating temperature is responsible for the changes observed in the catalyst.

MERCURY OXIDATION PROMOTED BY A SELECTIVE CATALYTIC REDUCTION CATALYST UNDER SIMULATED POWDER RIVER BASIN COAL COMBUSTION CONDITIONS

EPA Science Inventory

A bench-scale reactor consisting of a natural gas burner and an electrically heated reactor housing a selective catalytic reduction (SCR) catalyst was constructed for studying elemental mercury oxidation under SCR conditions. A low sulfur Power River Basin (PRB) coal combustion ...

Commercial-Scale Demonstration of the Liquid Phase Methanol (LPMEOH) Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

he Liquid Phase Methanol (LPMEOW) Demonstration Project at Kingsport Tennessee, is a $213.7 million cooperative agreement between the U.S. Department of Energy (DOE) and Air Products Liquid Phase Conversion Company, L.P. (the Partnership) to produce methanol from coal-derived synthesis gas (syngas). Air Products and Chemicals, Inc. (Air Products) and Eastman Chemical Company (Eastman) formed the Partnership to execute the Demonstration Project. The LPMEOEP Process Demonstration Unit was built at a site located at the Eastman coal-to-chemicals complex in Kingsport. The LPMEOHW Demonstration Facility completed its first year of operation on 02 April 1998. The LPMEOW Demonstration Facility also completed themore » longest continuous operating run (65 days) on 21 April 1998. Catalyst activity, as defined by the ratio of the rate constant at any point in time to the rate constant for freshly reduced catalyst (as determined in the laboratory autoclave), was monitored throughout the reporting period. During a six-week test at a reactor temperature of 225oC and Balanced Gas flowrate of 700 KSCFH, the rate of decline in catalyst activity was steady at 0.29-0.36% per day. During a second one-month test at a reactor temperature of 220oC and a Balanced Gas flowrate of 550-600 KSCFH, the rate of decline in catalyst activity was 0.4% per day, which matched the pefiorrnance at 225"C, as well as the 4-month proof-of-concept run at the LaPorte AFDU in 1988/89. Beginning on 08 May 1998, the LPMEOW Reactor temperature was increased to 235oC, which was the operating temperature tier the December 1997 restart with the fresh charge of catalyst (50'Yo of design loading). The flowrate of the primary syngas feed stream (Balanced Gas) was also increased to 700-750 KSCFH. During two stable operating periods between 08 May and 09 June 1998, the average catalyst deactivation rate was 0.8% per day. Due to the scatter of the statistical analysis of the results, this test was extended to better quanti& the catalyst aging behavior. During the reporting perio~ two batches of fresh catalyst were activated and transferred to the reactor (on 02 April and 20 June 1998). The weight of catalyst in the LPMEOW Reactor has reached 80% of the design value. At the end of the reporting period, a step-change in the pressure-drop profile within the LPMEOW Reactor and an increase in the pressure of the steam system which provides cooling to the LPMEOW Reactor were observed. No change in the calculated activity of the catalyst was detected during either of these transients. These parameters will be monitored closely for any additional changes.« less

Rotating Fluidized Bed Reactor for Space Nuclear Propulsion. Annual Report; Design Studies and Experimental Results

NASA Technical Reports Server (NTRS)

1971-01-01

The rotating fluidized bed reactor concept is being investigated for possible application in nuclear propulsion systems. Physics calculations show U-233 to be superior to U-235 as a fuel for a cavity reactor of this type. Preliminary estimates of the effect of hydrogen in the reactor, reflector material, and power peaking are given. A preliminary engineering analysis was made for U-235 and U-233 fueled systems. An evaluation of the parameters affecting the design of the system is given, along with the thrust-to-weight ratios. The experimental equipment is described, as are the special photographic techniques and procedures. Characteristics of the fluidized bed and experimental results are given, including photographic evidence of bed fluidization at high rotational velocities.

Evaluation of Bosch-Based Systems Using Non-Traditional Catalysts at Reduced Temperatures

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Mansell, J. Matthew

2011-01-01

Oxygen and water resupply make open loop atmosphere revitalization (AR) systems unfavorable for long-term missions beyond low Earth orbit. Crucial to closing the AR loop are carbon dioxide reduction systems with low mass and volume, minimal power requirements, and minimal consumables. For this purpose, NASA is exploring using Bosch-based systems. The Bosch process is favorable over state-of-the-art Sabatier-based processes due to complete loop closure. However, traditional operation of the Bosch required high reaction temperatures, high recycle rates, and significant consumables in the form of catalyst resupply due to carbon fouling. A number of configurations have been proposed for next-generation Bosch systems. First, alternative catalysts (catalysts other than steel wool) can be used in a traditional single-stage Bosch reactor to improve reaction kinetics and increase carbon packing density. Second, the Bosch reactor may be split into separate stages wherein the first reactor stage is dedicated to carbon monoxide and water formation via the reverse water-gas shift reaction and the second reactor stage is dedicated to carbon formation. A series system will enable maximum efficiency of both steps of the Bosch reaction, resulting in optimized operation and maximum carbon formation rate. This paper details the results of testing of both single-stage and two-stage Bosch systems with alternative catalysts at reduced temperatures. These results are compared to a traditional Bosch system operated with a steel wool catalyst.

Modeling phosphorus removal and recovery from anaerobic digester supernatant through struvite crystallization in a fluidized bed reactor.

PubMed

Rahaman, Md Saifur; Mavinic, Donald S; Meikleham, Alexandra; Ellis, Naoko

2014-03-15

The cost associated with the disposal of phosphate-rich sludge, the stringent regulations to limit phosphate discharge into aquatic environments, and resource shortages resulting from limited phosphorus rock reserves, have diverted attention to phosphorus recovery in the form of struvite (MAP: MgNH4PO4·6H2O) crystals, which can essentially be used as a slow release fertilizer. Fluidized-bed crystallization is one of the most efficient unit processes used in struvite crystallization from wastewater. In this study, a comprehensive mathematical model, incorporating solution thermodynamics, struvite precipitation kinetics and reactor hydrodynamics, was developed to illustrate phosphorus depletion through struvite crystal growth in a continuous, fluidized-bed crystallizer. A thermodynamic equilibrium model for struvite precipitation was linked to the fluidized-bed reactor model. While the equilibrium model provided information on supersaturation generation, the reactor model captured the dynamic behavior of the crystal growth processes, as well as the effect of the reactor hydrodynamics on the overall process performance. The model was then used for performance evaluation of the reactor, in terms of removal efficiencies of struvite constituent species (Mg, NH4 and PO4), and the average product crystal sizes. The model also determined the variation of species concentration of struvite within the crystal bed height. The species concentrations at two extreme ends (inlet and outlet) were used to evaluate the reactor performance. The model predictions provided a reasonably good fit with the experimental results for PO4-P, NH4-N and Mg removals. Predicated average crystal sizes also matched fairly well with the experimental observations. Therefore, this model can be used as a tool for performance evaluation and process optimization of struvite crystallization in a fluidized-bed reactor. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Alcohol synthesis in a high-temperature slurry reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, G.W.; Marquez, M.A.; McCutchen, M.S.

1995-12-31

The overall objective of this contract is to develop improved process and catalyst technology for producing higher alcohols from synthesis gas or its derivatives. Recent research has been focused on developing a slurry reactor that can operate at temperatures up to about 400{degrees}C and on evaluating the so-called {open_quotes}high pressure{close_quotes} methanol synthesis catalyst using this reactor. A laboratory stirred autoclave reactor has been developed that is capable of operating at temperatures up to 400{degrees}C and pressures of at least 170 atm. The overhead system on the reactor is designed so that the temperature of the gas leaving the system canmore » be closely controlled. An external liquid-level detector is installed on the gas/liquid separator and a pump is used to return condensed slurry liquid from the separator to the reactor. In order to ensure that gas/liquid mass transfer does not influence the observed reaction rate, it was necessary to feed the synthesis gas below the level of the agitator. The performance of a commercial {open_quotes}high pressure {close_quotes} methanol synthesis catalyst, the so-called {open_quotes}zinc chromite{close_quotes} catalyst, has been characterized over a range of temperature from 275 to 400{degrees}C, a range of pressure from 70 to 170 atm., a range of H{sub 2}/CO ratios from 0.5 to 2.0 and a range of space velocities from 2500 to 10,000 sL/kg.(catalyst),hr. Towards the lower end of the temperature range, methanol was the only significant product.« less

Poisoning of a silica supported cobalt catalyst due to the presence of sulfur impurities in syngas during Fischer-Tropsch synthesis: Effect of chelating agent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bambal, A.S.; Gardner, T.H.; Kugler, E.L.

2012-01-01

Sulfur compounds that are generally found in syngas derived from coal and biomass are a poison to Fischer-Tropsch (FT) catalysts. The presence of sulfur impurities in the ppm range can limit the life of a FT catalyst to a few hours or a few days. In this study, FT synthesis was carried out in a fixed-bed reactor at 230 °C, 20 bar, and 13,500 Ncm3/h/gcat for 72 h using syngas with H2/CO = 2.0. Cobalt-based catalysts were subjected to poisoning by 10 and 50 ppm sulfur in the syngas. The performance of FT catalyst was compared in context of syngasmore » conversion, product selectivities and yields, during the poisoning as well as post-poisoning stages. At both the impurity concentrations, the sulfur was noted to cause permanent loss in the activity, possibly by adsorbing irreversibly on the surface. The sulfur poison affects the hydrogenation and the chain-propagation ability of the catalysts, and shifts the product selectivity towards short-chain hydrocarbons with higher percentages of olefins. Additional diffusion limitations caused due to sulfur poisoning are thought to alter the product selectivity. The shifts in product selectivities suggest that the sulfur decreases the ability of the catalyst to form C-C bonds to produce longer-chain hydrocarbons. The selective blocking of sulfur is thought to affect the hydrogenation ability on the catalyst, resulting in more olefins in the product after sulfur poisoning. The sulfur poisoning on the cobalt catalyst is expected to cause an increase in the number of sites responsible for WGS or to influence the Boudouard reaction, resulting in a higher CO2 selectivity. Both the sites responsible for CO adsorptions as well as the sites for chain growth are poisoned during the poisoning. Additionally, the performance of a base-case cobalt catalyst is compared with that of catalysts modified by chelating agents (CAs). The superior performance of CA-modified catalysts during sulfur poisoning is attributed to the presence of smaller crystallite sizes and higher dispersions of cobalt on the support. Finally, the sulfur deactivation data is modeled by a simple kinetic expression to determine the deactivation constant, deactivation rates and half-life of the FT catalyst.« less

Hollow mesoporous silica nanotubes modified with palladium nanoparticles for environmental catalytic applications.

PubMed

Tian, Meng; Long, Yu; Xu, Dan; Wei, Shuoyun; Dong, Zhengping

2018-07-01

Nowadays, chemical catalytic methods for the treatment of organic wastes are attracting more and more research attention. In the current research, novel catalysts with palladium nanoparticles (Pd NPs) supported on the hollow mesoporous silica nanotubes (h-mSiO 2 ) were synthesized for the catalytic reduction of 4-nitrophenol (4-NP) and hydrodechlorination (HDC) of 4-chlorophenol (4-CP). The key point for the fabrication of the catalysts is that a certain thickness of the silica shell was wrapped on the multiwalled carbon nanotubes (MWNTs) or Pd/MWNTs through biphase stratification approach, and then the samples were calcined to remove the MWNTs. Thereby, h-mSiO 2 and Pd@h-mSiO 2 samples were obtained. The prepared materials have excellent pore structure and exhibit high specific surface areas. The reduction of 4-NP by the Pd/h-mSiO 2 and Pd@h-mSiO 2 catalysts showed higher TOF values than many other catalysts, and the yield of HDC of 4-CP to phenol reached 100% with a low loading of Pd in water solvent. The excellent catalytic activities of the Pd/h-mSiO 2 and Pd@h-mSiO 2 catalysts should attribute to the excellent connectivity of the h-mSiO 2 which not only can increase the accessibility of the Pd active sites but also enhance the mass transfer of the reactants. It is worth mention that, there is almost no Pd NPs aggregation or losing during the reaction process, and the prepared catalysts still showed good catalytic activity and physical stability after recycling. Moreover, the catalyst shows potential for catalytic reduction of nitroarenes in a fixed bed reactor, thus could be used for continuously treat nitroarenes polluted water. Copyright © 2018 Elsevier Inc. All rights reserved.

Trickle-bed root culture bioreactor design and scale-up: growth, fluid-dynamics, and oxygen mass transfer.

PubMed

Ramakrishnan, Divakar; Curtis, Wayne R

2004-10-20

Trickle-bed root culture reactors are shown to achieve tissue concentrations as high as 36 g DW/L (752 g FW/L) at a scale of 14 L. Root growth rate in a 1.6-L reactor configuration with improved operational conditions is shown to be indistinguishable from the laboratory-scale benchmark, the shaker flask (mu=0.33 day(-1)). These results demonstrate that trickle-bed reactor systems can sustain tissue concentrations, growth rates and volumetric biomass productivities substantially higher than other reported bioreactor configurations. Mass transfer and fluid dynamics are characterized in trickle-bed root reactors to identify appropriate operating conditions and scale-up criteria. Root tissue respiration goes through a minimum with increasing liquid flow, which is qualitatively consistent with traditional trickle-bed performance. However, liquid hold-up is much higher than traditional trickle-beds and alternative correlations based on liquid hold-up per unit tissue mass are required to account for large changes in biomass volume fraction. Bioreactor characterization is sufficient to carry out preliminary design calculations that indicate scale-up feasibility to at least 10,000 liters.

A Novel Slurry-Based Biomass Reforming Process Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Emerson, Sean C.; Davis, Timothy D.; Peles, A.

2011-09-30

This project was focused on developing a catalytic means of producing H2 from raw, ground biomass, such as fast growing poplar trees, willow trees, or switch grass. The use of a renewable, biomass feedstock with minimal processing can enable a carbon neutral means of producing H2 in that the carbon dioxide produced from the process can be used in the environment to produce additional biomass. For economically viable production of H2, the biomass is hydrolyzed and then reformed without any additional purification steps. Any unreacted biomass and other byproduct streams are burned to provide process energy. Thus, the development ofmore » a catalyst that can operate in the demanding corrosive environment and presence of potential poisons is vital to this approach. The concept for this project is shown in Figure 1. The initial feed is assumed to be a >5 wt% slurry of ground wood in dilute base, such as potassium carbonate (K2CO3). Base hydrolysis and reforming of the wood is carried out at high but sub-critical pressures and temperatures in the presence of a solid catalyst. A Pd alloy membrane allows the continuous removal of pure , while the retentate, including methane is used as fuel in the plant. The project showed that it is possible to economically produce H2 from woody biomass in a carbon neutral manner. Technoeconomic analyses using HYSYS and the DOE's H2A tool [1] were used to design a 2000 ton day-1 (dry basis) biomass to hydrogen plant with an efficiency of 46% to 56%, depending on the mode of operation and economic assumptions, exceeding the DOE 2012 target of 43%. The cost of producing the hydrogen from such a plant would be in the range of $1/kg H2 to $2/kg H2. By using raw biomass as a feedstock, the cost of producing hydrogen at large biomass consumption rates is more cost effective than steam reforming of hydrocarbons or biomass gasification and can achieve the overall cost goals of the DOE Fuel Cell Technologies Program. The complete conversion of wood to hydrogen, methane, and carbon dioxide was repeatedly demonstrated in batch reactors varying in size from 50 mL to 7.6 L. The different wood sources (e.g., swamp maple, poplar, and commercial wood flour) were converted in the presence of a heterogeneous catalyst and base at relatively low temperatures (e.g., 310°C) at sub-critical pressures sufficient to maintain the liquid phase. Both precious metal and base metal catalysts were found to be active for the liquid phase hydrolysis and reforming of wood. Pt-based catalysts, particularly Pt-Re, were shown to be more selective toward breaking C-C bonds, resulting in a higher selectivity to hydrogen versus methane. Ni-based catalysts were found to prefer breaking C-O bonds, favoring the production of methane. The project showed that increasing the concentration of base (base to wood ratio) in the presence of Raney Ni catalysts resulted in greater selectivity toward hydrogen but at the expense of increasing the production of undesirable organic acids from the wood, lowering the amount of wood converted to gas. It was shown that by modifying Ni-based catalysts with dopants, it was possible to reduce the base concentration while maintaining the selectivity toward hydrogen and increasing wood conversion to gas versus organic acids. The final stage of the project was the construction and testing of a demonstration unit for H2 production. This continuous flow demonstration unit consisted of wood slurry and potassium carbonate feed pump systems, two reactors for hydrolysis and reforming, and a gas-liquid separation system. The technical challenges associated with unreacted wood fines and Raney Ni catalyst retention limited the demonstration unit to using a fixed bed Raney Ni catalyst form. The lower activity of the larger particle Raney Ni in turn limited the residence time and thus the wood mass flow feed rate to 50 g min-1 for a 1 wt% wood slurry. The project demonstrated continuous H2 yields with unmodified, fixed bed Raney Ni, from 63% to 100% with corresponding H2 selectivities of 6% to 21%, for periods of several hours. The fixed bed form of the Raney Ni exhibited signs of deactivation which requires further study.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Underwood, R.P.

As part of the DOE-sponsored contract Synthesis of Dimethyl Ether and Alternative Fuels in the Liquid Phase from Coal-Derived Syngas'' experimental evaluations of the one-step synthesis of alternative fuels were carried out. The objective of this work was to develop novel processes for converting coal-derived syngas to fuels or fuel additives. Building on a technology base acquired during the development of the Liquid Phase Methanol (LPMEOH) process, this work focused on the development of slurry reactor based processes. The experimental investigations, which involved bench-scale reactor studies, focused primarily on three areas: (1) One-step, slurry-phase syngas conversion to hydrocarbons or methanol/hydrocarbonmore » mixtures using a mixture of methanol synthesis catalyst and methanol conversion catalyst in the same slurry reactor. (2) Slurry-phase conversion of syngas to mixed alcohols using various catalysts. (3) One-step, slurry-phase syngas conversion to mixed ethers using a mixture of mixed alcohols synthesis catalyst and dehydration catalyst in the same slurry reactor. The experimental results indicate that, of the three types of processes investigated, slurry phase conversion of syngas to mixed alcohols shows the most promise for further process development. Evaluations of various mixed alcohols catalysts show that a cesium-promoted Cu/ZnO/Al[sub 2]O[sub 3] methanol synthesis catalyst, developed in Air Products' laboratories, has the highest performance in terms of rate and selectivity for C[sub 2+]-alcohols. In fact, once-through conversion at industrially practical reaction conditions yielded a mixed alcohols product potentially suitable for direct gasoline blending. Moreover, an additional attractive aspect of this catalyst is its high selectivity for branched alcohols, potential precursors to iso-olefins for use in etherification.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Underwood, R.P.

As part of the DOE-sponsored contract ``Synthesis of Dimethyl Ether and Alternative Fuels in the Liquid Phase from Coal-Derived Syngas`` experimental evaluations of the one-step synthesis of alternative fuels were carried out. The objective of this work was to develop novel processes for converting coal-derived syngas to fuels or fuel additives. Building on a technology base acquired during the development of the Liquid Phase Methanol (LPMEOH) process, this work focused on the development of slurry reactor based processes. The experimental investigations, which involved bench-scale reactor studies, focused primarily on three areas: (1) One-step, slurry-phase syngas conversion to hydrocarbons or methanol/hydrocarbonmore » mixtures using a mixture of methanol synthesis catalyst and methanol conversion catalyst in the same slurry reactor. (2) Slurry-phase conversion of syngas to mixed alcohols using various catalysts. (3) One-step, slurry-phase syngas conversion to mixed ethers using a mixture of mixed alcohols synthesis catalyst and dehydration catalyst in the same slurry reactor. The experimental results indicate that, of the three types of processes investigated, slurry phase conversion of syngas to mixed alcohols shows the most promise for further process development. Evaluations of various mixed alcohols catalysts show that a cesium-promoted Cu/ZnO/Al{sub 2}O{sub 3} methanol synthesis catalyst, developed in Air Products` laboratories, has the highest performance in terms of rate and selectivity for C{sub 2+}-alcohols. In fact, once-through conversion at industrially practical reaction conditions yielded a mixed alcohols product potentially suitable for direct gasoline blending. Moreover, an additional attractive aspect of this catalyst is its high selectivity for branched alcohols, potential precursors to iso-olefins for use in etherification.« less

Methods and apparatuses for deoxygenating pyrolysis oil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baird, Lance Awender; Brandvold, Timothy A.; Frey, Stanley Joseph

Methods and apparatuses are provided for deoxygenating pyrolysis oil. A method includes contacting a pyrolysis oil with a deoxygenation catalyst in a first reactor at deoxygenation conditions to produce a first reactor effluent. The first reactor effluent has a first oxygen concentration and a first hydrogen concentration, based on hydrocarbons in the first reactor effluent, and the first reactor effluent includes an aromatic compound. The first reactor effluent is contacted with a dehydrogenation catalyst in a second reactor at conditions that deoxygenate the first reactor effluent while preserving the aromatic compound to produce a second reactor effluent. The second reactormore » effluent has a second oxygen concentration lower than the first oxygen concentration and a second hydrogen concentration that is equal to or lower than the first hydrogen concentration, where the second oxygen concentration and the second hydrogen concentration are based on the hydrocarbons in the second reactor effluent.« less

Heat pump apparatus

DOEpatents

Nelson, Paul A.; Horowitz, Jeffrey S.

1983-01-01

A heat pump apparatus including a compact arrangement of individual tubular reactors containing hydride-dehydride beds in opposite end sections, each pair of beds in each reactor being operable by sequential and coordinated treatment with a plurality of heat transfer fluids in a plurality of processing stages, and first and second valves located adjacent the reactor end sections with rotatable members having multiple ports and associated portions for separating the hydride beds at each of the end sections into groups and for simultaneously directing a plurality of heat transfer fluids to the different groups. As heat is being generated by a group of beds, others are being regenerated so that heat is continuously available for space heating. As each of the processing stages is completed for a hydride bed or group of beds, each valve member is rotated causing the heat transfer fluid for the heat processing stage to be directed to that bed or group of beds. Each of the end sections are arranged to form a closed perimeter and the valve member may be rotated repeatedly about the perimeter to provide a continuous operation. Both valves are driven by a common motor to provide a coordinated treatment of beds in the same reactors. The heat pump apparatus is particularly suitable for the utilization of thermal energy supplied by solar collectors and concentrators but may be used with any source of heat, including a source of low-grade heat.

Improving hydrocarbon yield from catalytic fast co-pyrolysis of hemicellulose and plastic in the dual-catalyst bed of CaO and HZSM-5.

PubMed

Ding, Kuan; Zhong, Zhaoping; Wang, Jia; Zhang, Bo; Fan, Liangliang; Liu, Shiyu; Wang, Yunpu; Liu, Yuhuan; Zhong, Daoxu; Chen, Paul; Ruan, Roger

2018-08-01

The high concentration of oxygenated compounds in pyrolytic products prohibits the conversion of hemicellulose to important biofuels and chemicals via fast pyrolysis. Herein a dual-catalyst bed of CaO and HZSM-5 was developed to convert acids in the pyrolytic products of xylan to valuable hydrocarbons. Meanwhile, LLDPE was co-pyrolyzed with xylan to supplement hydrogen during the catalysis of HZSM-5. The results showed that CaO could effectively transform acids into ketones. A minimum yield of acids (2.74%) and a maximum yield of ketones (42.93%) were obtained at a catalyst to feedstock ratio of 2:1. The dual-catalyst bed dramatically increased the yield of aromatics. Moreover, hydrogen-rich fragments derived from LLDPE promoted the Diels-Alder reactions of furans and participated in the hydrocarbon pool reactions of non-furanic compounds. As a result, a higher yield of hydrocarbons was achieved. This study provides a fundamental for recovering energy and chemicals from pyrolysis of hemicellulose. Copyright © 2018 Elsevier Ltd. All rights reserved.

Separation of catalyst from Fischer-Tropsch slurry

DOEpatents

White, Curt M.; Quiring, Michael S.; Jensen, Karen L.; Hickey, Richard F.; Gillham, Larry D.

1998-10-27

In a catalytic process for converting synthesis gas including hydrogen and carbon monoxide to hydrocarbons and oxygenates by a slurry Fischer-Tropsch synthesis, the wax product along with dispersed catalyst is removed from the slurry and purified by removing substantially all of the catalyst prior to upgrading the wax and returning a portion to the Fischer-Tropsch reaction. Separation of the catalyst particles from the wax product is accomplished by dense gas and/or liquid extraction in which the organic compounds in the wax are dissolved and carried away from the insoluble inorganic catalyst particles that are primarily inorganic in nature. The purified catalyst free wax product can be subsequently upgraded by various methods such as hydrogenation, isomerization, hydrocracking, conversion to gasoline and other products over ZSM-5 aluminosilicate zeolite, etc. The catalyst particles are returned to the Fischer-Tropsch Reactor by slurring them with a wax fraction of appropriate molecular weight, boiling point and viscosity to avoid reactor gelation.

A Theoretical Investigation of Oxidation Efficiency of a Volatile Removal Assembly Reactor Under Microgravity Conditions

NASA Technical Reports Server (NTRS)

Guo, Boyun

2005-01-01

Volatile Removal Assembly (VRA) is a subsystem of the Closed Environment Life Support System (CELSS) installed in the International Space Station. It is used for removing contaminants (volatile organics) in the wastewater produced by the space station crews. The major contaminants are formic acid, ethanol, and propylene glycol. The VRA contains a slim packbed reactor (3.5 cm diameter and four 28 cm long tubes in series) to perform catalyst oxidation of wastewater at elevated pressure and temperature under microgravity conditions. In the reactor, the contaminants are burned with oxygen gas (O2) to form water and carbon dioxide (CO2) that dissolves in the water stream. Optimal design of the reactor requires a thorough understanding about how the reactor performs under microgravity conditions. The objective of this study was to develop a mathematical model to interpret experimental data obtained from normal and microgravity conditions, and to predict the performance of VRA reactor under microgravity conditions. Catalyst oxidation kinetics and the total oxygen-water contact area control the efficiency of catalyst oxidation for mass transfer, which depends on oxygen gas holdup and distribution in the reactor. The process involves bubbly flow in porous media with chemical reactions in microgravity environment. This presents a unique problem in fluid dynamics that has not been studied. Guo et al. (2004) developed a mathematical model that predicts oxygen holdup in the VRA reactor. No mathematical model has been found in the literature that can be used to predict the efficiency of catalyst oxidation under microgravity conditions.

The e-beam sustained CO2 laser amplifier

NASA Technical Reports Server (NTRS)

Brown, M. J.; Shaw, S. R.; Evans, M. H.; Smith, I. M.; Holman, W.

1990-01-01

The design features of an e-beam sustained CO2 amplifier are described. The amplifier is designed specifically as a catalyst test-bed to study the performance of room temperature precious metal CO-oxidation catalysts under e-beam sustained operation. The amplifier has been designed to provide pulse durations of 30 microseconds in a discharge volume of 2 litres. With a gas flow velocity of 2 metres per second, operation at repetition rates of 10 Hz is accommodated. The system is designed for sealed-off operation and a catalyst bed is housed in the gas circulation system downstream from the discharge region. CO and oxygen monitors are used for diagnosis of gas composition in the amplifier so that catalyst performance can be monitored in situ during sealed lifetests.

Alkylation of organic aromatic compounds

DOEpatents

Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

1993-09-07

Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a molecular sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene to about the mid point of the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 figures.

Alkylation of organic aromatic compounds

DOEpatents

Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

1993-01-01

Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene to about the mid point of the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

A BGO detector for Positron Emission Profiling in catalysts

NASA Astrophysics Data System (ADS)

Mangnus, A. V. G.; van Ijzendoorn, L. J.; de Goeij, J. J. M.; Cunningham, R. H.; van Santen, R. A.; de Voigt, M. J. A.

1995-05-01

As part of a project to study the reaction kinetics in catalysts, a detector system has been designed and built. The detector will measure in one dimension the activity distribution of positron emitters in catalyst reactors under operational conditions as a function of time. The detector consists of two arrays of ten BGO crystals each and has the flexibility to measure with high sensitivity the activity profile in various reactor sizes; the position resolution that can be reached is 3 mm.

Packed bed reactor for photochemical .sup.196 Hg isotope separation

DOEpatents

Grossman, Mark W.; Speer, Richard

1992-01-01

Straight tubes and randomly oriented pieces of tubing having been employed in a photochemical mercury enrichment reactor and have been found to improve the enrichment factor (E) and utilization (U) compared to a non-packed reactor. One preferred embodiment of this system uses a moving bed (via gravity) for random packing.

Nuclear Thermal Propulsion: A Joint NASA/DOE/DOD Workshop

NASA Technical Reports Server (NTRS)

Clark, John S. (Editor)

1991-01-01

Papers presented at the joint NASA/DOE/DOD workshop on nuclear thermal propulsion are compiled. The following subject areas are covered: nuclear thermal propulsion programs; Rover/NERVA and NERVA systems; Low Pressure Nuclear Thermal Rocket (LPNTR); particle bed reactor nuclear rocket; hybrid propulsion systems; wire core reactor; pellet bed reactor; foil reactor; Droplet Core Nuclear Rocket (DCNR); open cycle gas core nuclear rockets; vapor core propulsion reactors; nuclear light bulb; Nuclear rocket using Indigenous Martian Fuel (NIMF); mission analysis; propulsion and reactor technology; development plans; and safety issues.

Pressurized fluidized bed reactor

DOEpatents

Isaksson, J.

1996-03-19

A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine. 1 fig.

Pressurized fluidized bed reactor

DOEpatents

Isaksson, Juhani

1996-01-01

A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine.

40 CFR 63.1579 - What definitions apply to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... regeneration of catalyst in situ in any one of several reactors (e.g., 4 or 5 separate reactors) that can be..., wet injection, or caustic injection control device that treats (in-situ) the catalytic reforming unit...) at specified intervals or at the owner's or operator's convenience for in situ catalyst regeneration...

40 CFR 63.1579 - What definitions apply to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... regeneration of catalyst in situ in any one of several reactors (e.g., 4 or 5 separate reactors) that can be..., wet injection, or caustic injection control device that treats (in-situ) the catalytic reforming unit...) at specified intervals or at the owner's or operator's convenience for in situ catalyst regeneration...

40 CFR 63.1579 - What definitions apply to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... regeneration of catalyst in situ in any one of several reactors (e.g., 4 or 5 separate reactors) that can be..., wet injection, or caustic injection control device that treats (in-situ) the catalytic reforming unit...) at specified intervals or at the owner's or operator's convenience for in situ catalyst regeneration...

Novel windows for "solar commodities": a device for CO2 reduction using plasmonic catalyst activation.

PubMed

Navarrete, Alexander; Muñoz, Sergio; Sanz-Moral, Luis M; Brandner, Juergen J; Pfeifer, Peter; Martín, Ángel; Dittmeyer, Roland; Cocero, María J

2015-01-01

A novel plasmonic reactor concept is proposed and tested to work as a visible energy harvesting device while allowing reactions to transform CO2 to be carried out. Particularly the reverse water gas shift (RWGS) reaction has been tested as a means to introduce renewable energy into the economy. The development of the new reactor concept involved the synthesis of a new composite capable of plasmonic activation with light, the development of an impregnation method to create a single catalyst reactor entity, and finally the assembly of a reaction system to test the reaction. The composite developed was based on a Cu/ZnO catalyst dispersed into transparent aerogels. This allows efficient light transmission and a high surface area for the catalyst. An effective yet simple impregnation method was developed that allowed introduction of the composites into glass microchannels. The activation of the reaction was made using LEDs that covered all the sides of the reactor allowing a high power delivery. The results of the reaction show a stable process capable of low temperature transformations.

Catalyst Residence Time Distributions in Riser Reactors for Catalytic Fast Pyrolysis. Part 2: Pilot-Scale Simulations and Operational Parameter Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foust, Thomas D.; Ziegler, Jack L.; Pannala, Sreekanth

2017-02-21

Here, wsing the validated simulation model developed in part one of this study for biomass catalytic fast pyrolysis (CFP), we assess the functional utility of using this validated model to assist in the development of CFP processes in fluidized catalytic cracking (FCC) reactors to a commercially viable state. Specifically, we examine the effects of mass flow rates, boundary conditions (BCs), pyrolysis vapor molecular weight variation, and the impact of the chemical cracking kinetics on the catalyst residence times. The factors that had the largest impact on the catalyst residence time included the feed stock molecular weight and the degree ofmore » chemical cracking as controlled by the catalyst activity. Lastly, because FCC reactors have primarily been developed and utilized for petroleum cracking, we perform a comparison analysis of CFP with petroleum and show the operating regimes are fundamentally different.« less

Attrition Resistant Iron-Based Fischer-Tropsch Catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jothimurugesan, K.; Goodwin, J.G.; Spivey, J.J.

1997-03-26

The Fischer-Tropsch (F-T) reaction provides a way of converting coal-derived synthesis gas (CO+H{sub 2}) to liquid fuels. Since the reaction is highly exothermic, one of the major problems in control of the reaction is heat removal. Recent work has shown that the use of slurry bubble column reactors (SBCRS) can largely solve this problem. Iron-based (Fe) catalysts are preferred catalysts for F-T when using low CO/H{sub 2} ratio synthesis gases derived from modem coal gasifiers. This is because in addition to reasonable F-T activity, the FT catalysts also possess high water gas shift (WGS) activity. However, a serious problem withmore » the use of Fe catalysts in a SBCR is their tendency to undergo attrition. This can cause fouling/plugging of downstream filters and equipment, making the separation of catalyst from the oil/wax product very difficult if not impossible, and results in a steady loss of catalyst from the reactor. The objectives of this research are to develop a better understanding of the parameters affecting attrition resistance of Fe F-T catalysts suitable for use in SBCRs and to incorporate this understanding into the design of novel Fe catalysts having superior attrition resistance. Catalyst preparations will be based on the use of spray drying and will be scalable using commercially available equipment. The research will employ among other measurements, attrition testing and F-T synthesis, including long duration slurry reactor runs in order to ascertain the degree of success of the various preparations. The goal is to develop an Fe catalyst which can be used in a SBCR having only an internal filter for separation of the catalyst from the liquid product, without sacrificing F-T activity and selectivity.« less

Attrition Resistant Iron-Based Fischer-Tropsch Catalysts.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jothimurugesan, K.; Goodwin, J.S.; Spivey, J.J.

1997-09-22

The Fischer-Tropsch (F-T) reaction provides a way of converting coal-derived synthesis gas (CO and H{sub 2}) to liquid fuels. Since the reaction is highly exothermic, one of the major problems in control of the reaction is heat removal. Recent work has shown that the use of slurry bubble column reactors (SBCRs) can largely solve this problem. Iron-based (Fe) catalysts are preferred catalysts for F-T when using low CO/H{sub 2} ratio synthesis gases derived from modern coal gasifiers. This is because in addition to reasonable F-T activity, the F-T catalysts also possess high water gas shift (WGS) activity. However, a seriousmore » problem with the use of Fe catalysts in a SBCR is their tendency to undergo attrition. This can cause fouling/plugging of downstream filters and equipment, making the separation of catalyst from the oil/wax product very difficult if not impossible, and results in a steady loss of catalyst from the reactor. The objectives of this research are to develop a better understanding of the parameters affecting attrition resistance of Fe F-T catalysts suitable for use in SBCRs and to incorporate this understanding into the design of novel Fe catalysts having superior attrition resistance. Catalyst preparations will be based on the use of spray drying and will be scalable using commercially available equipment. The research will employ among other measurements, attrition testing and F-T synthesis, including long duration slurry reactor runs in order to ascertain the degree of success of the various preparations. The goal is to develop an Fe catalyst which can be used in a SBCR having only an internal filter for separation of the catalyst from the liquid product, without sacrificing F-T activity and selectivity.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Setyopratomo, P., E-mail: puguh-sptm@yahoo.com; Wulan, Praswasti P. D. K., E-mail: wulanmakmur@gmail.com; Sudibandriyo, M., E-mail: msudib@che.ui.ac.id

Carbon nanotubes were produced by chemical vapor deposition method to meet the specifications for hydrogen storage. So far, the various catalyst had been studied outlining their activities, performances, and efficiencies. In this work, tri-metallic catalyst consist of Fe-Co-Mo supported on MgO was used. The catalyst was prepared by wet-impregnation method. Liquefied Petroleum Gas (LPG) was used as carbon source. The synthesis was conducted in atmospheric fixed bed reactor at reaction temperature range 750 – 850 °C for 30 minutes. The impregnation method applied in this study successfully deposed metal component on the MgO support surface. It found that the depositedmore » metal components might partially replace Mg(OH){sub 2} or MgO molecules in their crystal lattice. Compare to the original MgO powder; it was significant increases in pore volume and surface area has occurred during catalyst preparation stages. The size of obtained carbon nanotubes is ranging from about 10.83 nm OD/4.09 nm ID up to 21.84 nm OD/6.51 nm ID, which means that multiwall carbon nanotubes were formed during the synthesis. Yield as much as 2.35 g.CNT/g.catalyst was obtained during 30 minutes synthesis and correspond to carbon nanotubes growth rate of 0.2 μm/min. The BET surface area of the obtained carbon nanotubes is 181.13 m{sup 2}/g and around 50 % of which is contributed by mesopores. Micropore with half pore width less than 1 nm contribute about 10% volume of total micro and mesopores volume of the carbon nanotubes. The existence of these micropores is very important to increase the hydrogen storage capacity of the carbon nanotubes.« less

Role of the Support and Reaction Conditions on the Vapor-Phase Deoxygenation of m-Cresol over Pt/C and Pt/TiO 2 Catalysts

DOE PAGES

Griffin, Michael B.; Ferguson, Glen A.; Ruddy, Daniel A.; ...

2016-03-23

The catalytic deoxygenation of biomass fast pyrolysis vapors offers a promising route for the sustainable production of liquid transportation fuels. However, a clear understanding of the mechanistic details involved in this process has yet to be achieved, and questions remain regarding the role of the catalyst support and the influence of reaction conditions. In order to gain insight into these questions, the deoxygenation of m-cresol was investigated over Pt/C and Pt/TiO 2 catalysts using experimental and computational techniques. The performance of each catalyst was evaluated in a packed-bed reactor under two conditions (523 K, 2.0 MPa and 623 K, 0.5more » MPa), and the energetics of the ring hydrogenation, direct deoxygenation, and tautomerization mechanisms were calculated over hydrogen-covered Pt(111) and oxygen vacancies on the surface of TiO 2(101). Over Pt(111), ring hydrogenation to 3-methylcyclohexanone and 3-methylcyclohexanol was found to be the most energetically favorable pathway. Over TiO 2(101), tautomerization and direct deoxygenation to toluene were identified as additional energetically favorable routes. These calculations are consistent with the experimental data, in which Pt/TiO 2 was more active on a metal site basis and exhibited higher selectivity to toluene at 623 K relative to Pt/C. On the basis of these results, it is likely that the reactivity of Pt/TiO 2 and Pt/C is driven by the metallic phase at 523 K, while contributions from the TiO 2 support enhance deoxygenation at 623 K. These results highlight the synergistic effects between hydrogenation catalysts and reducible metal oxide supports and provide insight into the reaction pathways responsible for their enhanced deoxygenation performance.« less

JPL in-house fluidized-bed reactor research

NASA Technical Reports Server (NTRS)

Rohatgi, N. K.

1984-01-01

Fluidized bed reactor research techniques for fabrication of quartz linears was reviewed. Silane pyrolysis was employed in this fabrication study. Metallic contaminant levels in the silicon particles were below levels detectable by emission spectroscopy.

Styrene recovery from polystyrene by flash pyrolysis in a conical spouted bed reactor.

PubMed

Artetxe, Maite; Lopez, Gartzen; Amutio, Maider; Barbarias, Itsaso; Arregi, Aitor; Aguado, Roberto; Bilbao, Javier; Olazar, Martin

2015-11-01

Continuous pyrolysis of polystyrene has been studied in a conical spouted bed reactor with the main aim of enhancing styrene monomer recovery. Thermal degradation in a thermogravimetric analyser was conducted as a preliminary study in order to apply this information in the pyrolysis in the conical spouted bed reactor. The effects of temperature and gas flow rate in the conical spouted bed reactor on product yield and composition have been determined in the 450-600°C range by using a spouting velocity from 1.25 to 3.5 times the minimum one. Styrene yield is strongly influenced by both temperature and gas flow rate, with the maximum yield being 70.6 wt% at 500°C and a gas velocity twice the minimum one. Copyright © 2015 Elsevier Ltd. All rights reserved.

Upgrades to the ISS Water Recovery System

NASA Technical Reports Server (NTRS)

Kayatin, Matthew J.; Carter, Donald L.; Schunk, Richard G.; Pruitt, Jennifer M.

2016-01-01

The International Space Station Water Recovery System (WRS) is comprised of the Water Processor Assembly (WPA) and the Urine Processor Assembly (UPA). The WRS produces potable water from a combination of crew urine (first processed through the UPA), crew latent, and Sabatier product water. Though the WRS has performed well since operations began in November 2008, several modifications have been identified to improve the overall system performance. These modifications can reduce resupply and improve overall system reliability, which is beneficial for the ongoing ISS mission as well as for future NASA manned missions. The following paper details efforts to reduce the resupply mass of the WPA Multifiltration Bed, develop improved catalyst for the WPA Catalytic Reactor, evaluate optimum operation of UPA through parametric testing, and improve reliability of the UPA fluids pump and Distillation Assembly.

Pyrolysis of polyolefins for increasing the yield of monomers' recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donaj, Pawel J., E-mail: pawel@mse.kth.se; Kaminsky, W.; Buzeto, F.

2012-05-15

Highlights: Black-Right-Pointing-Pointer Thermal and catalytic pyrolysis of mixed polyolefins in fluidized bed has been studied. Black-Right-Pointing-Pointer We tested applicability of a commercial Ziegler-Natta catalyst (Z-N: TiCl{sub 4}/MgCl{sub 2}). Black-Right-Pointing-Pointer The catalyst has a strong influence on product distribution, increasing gas fraction. Black-Right-Pointing-Pointer At 650 Degree-Sign C the monomer generation increased by 55% when the catalyst was used. Black-Right-Pointing-Pointer We showed the concept of treatment of mixed polyolefins without a need of separation. - Abstract: Pyrolysis of plastic waste is an alternative way of plastic recovery and could be a potential solution for the increasing stream of solid waste. The objectivemore » of this work was to increase the yield the gaseous olefins (monomers) as feedstock for polymerization process and to test the applicability of a commercial Ziegler-Natta (Z-N): TiCl{sub 4}/MgCl{sub 2} for cracking a mixture of polyolefins consisted of 46% wt. of low density polyethylene (LDPE), 30% wt. of high density polyethylene (HDPE) and 24% wt. of polypropylene (PP). Two sets of experiments have been carried out at 500 and 650 Degree-Sign C via catalytic pyrolysis (1% of Z-N catalyst) and at 650 and 730 Degree-Sign C via only-thermal pyrolysis. These experiments have been conducted in a lab-scale, fluidized quartz-bed reactor of a capacity of 1-3 kg/h at Hamburg University. The results revealed a strong influence of temperature and presence of catalyst on the product distribution. The ratios of gas/liquid/solid mass fractions via thermal pyrolysis were: 36.9/48.4/15.7% wt. and 42.4/44.7/13.9% wt. at 650 and 730 Degree-Sign C while via catalytic pyrolysis were: 6.5/89.0/4.5% wt. and 54.3/41.9/3.8% wt. at 500 and 650 Degree-Sign C, respectively. At 650 Degree-Sign C the monomer generation increased by 55% up to 23.6% wt. of total pyrolysis products distribution while the catalyst was added. Obtained yields of olefins were compared with the naphtha steam cracking process and other potentially attractive processes for feedstock generation. The concept of closed cycle material flow for polyolefins has been discussed, showing the potential benefits of feedstock recycling in a plastic waste management.« less

Development of a high-temperature durable catalyst for use in catalytic combustors for advanced automotive gas turbine engines

NASA Astrophysics Data System (ADS)

Tong, H.; Snow, G. C.; Chu, E. K.; Chang, R. L. S.; Angwin, M. J.; Pessagno, S. L.

1981-09-01

Durable catalytic reactors for advanced gas turbine engines were developed. Objectives were: to evaluate furnace aging as a cost effective catalytic reactor screening test, measure reactor degradation as a function of furnace aging, demonstrate 1,000 hours of combustion durability, and define a catalytic reactor system with a high probability of successful integration into an automotive gas turbine engine. Fourteen different catalytic reactor concepts were evaluated, leading to the selection of one for a durability combustion test with diesel fuel for combustion conditions. Eight additional catalytic reactors were evaluated and one of these was successfully combustion tested on propane fuel. This durability reactor used graded cell honeycombs and a combination of noble metal and metal oxide catalysts. The reactor was catalytically active and structurally sound at the end of the durability test.

Development of a high-temperature durable catalyst for use in catalytic combustors for advanced automotive gas turbine engines

NASA Technical Reports Server (NTRS)

Tong, H.; Snow, G. C.; Chu, E. K.; Chang, R. L. S.; Angwin, M. J.; Pessagno, S. L.

1981-01-01

Durable catalytic reactors for advanced gas turbine engines were developed. Objectives were: to evaluate furnace aging as a cost effective catalytic reactor screening test, measure reactor degradation as a function of furnace aging, demonstrate 1,000 hours of combustion durability, and define a catalytic reactor system with a high probability of successful integration into an automotive gas turbine engine. Fourteen different catalytic reactor concepts were evaluated, leading to the selection of one for a durability combustion test with diesel fuel for combustion conditions. Eight additional catalytic reactors were evaluated and one of these was successfully combustion tested on propane fuel. This durability reactor used graded cell honeycombs and a combination of noble metal and metal oxide catalysts. The reactor was catalytically active and structurally sound at the end of the durability test.

Catalytic decomposition of gaseous 1,2-dichlorobenzene over CuOx/TiO₂ and CuOx/TiO₂-CNTs catalysts: Mechanism and PCDD/Fs formation.

PubMed

Wang, Qiu-lin; Huang, Qun-xing; Wu, Hui-fan; Lu, Sheng-yong; Wu, Hai-long; Li, Xiao-dong; Yan, Jian-hua

2016-02-01

Gaseous 1,2-dichlorobenzene (1,2-DCBz) was catalytically decomposed in a fixed-bed catalytic reactor using composite copper-based titanium oxide (CuOx/TiO2) catalysts with different copper ratios. Carbon nanotubes (CNTs) were introduced to produce novel CuOx/TiO2-CNTs catalysts by the sol-gel method. The catalytic performances of CuOx/TiO2 and CuOx/TiO2-CNTs on 1,2-DCBz oxidative destruction under different temperatures (150-350 °C) were experimentally examined and the correlation between catalyst structure and catalytic activity was characterized and the role of oxygen in catalytic reaction was discussed. Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) generation during 1,2-DCBz catalytic oxidation by CuOx/TiO2-CNTs composite catalyst was also examined. Results indicate that the 1,2-DCBz destruction/removal efficiencies of CuOx (4 wt%)/TiO2 catalyst at 150 °C and 350 °C with a GHSV of 3400 h(-1) are 59% and 94% respectively and low-temperature (150 °C) catalytic activity of CuOx/TiO2 on 1,2-DCBz oxidation can be improved from 59 to 77% when CNTs are introduced. Furthermore, oxygen either in catalyst or from reaction atmosphere is indispensible in reaction. The former is offered to activate and oxidize the 1,2-DCBz adsorbed on catalyst, thus can be generally consumed during reaction and the oxygen content in catalyst is observed lost from 39.9 to 35.0 wt% after reacting under inert atmosphere; the latter may replenish the vacancy in catalyst created by the consumed oxygen thus extends the catalyst life and raises the destruction/removal efficiency. The introduction of CNTs also increases the Cu(2+)/Cu(+) ratio, chemisorbed oxygen concentration and surface lattice oxygen binding energy which are closely related with catalytic activity. PCDD/Fs is confirmed to be formed when 1,2-DCBz catalytically oxidized by CuOx/TiO2-CNTs composite catalyst with sufficient oxygen (21%), proper temperature (350 °C) and high concentration of 1,2-DCBz feed (120 ppm). Copyright © 2015 Elsevier Ltd. All rights reserved.

Particulate fuel bed tests

NASA Astrophysics Data System (ADS)

Horn, F. L.; Powell, J. R.; Savino, J. M.

Gas-cooled reactors using packed beds of small-diameter, coated fuel particles have been proposed for compact, high-power systems. To test the thermal-hydraulic performance of the particulate reactor fuel under simulated reactor conditions, a bed of 800-micrometer diameter particles was heated by its electrical resistance current and cooled by flowing helium gas. The specific resistance of the bed composed of pyrocarbon-coated particles was measured at several temperatures, and found to be 0.09 ohm-cm at 1273 K and 0.06 ohm-cm at 1600 K. The maximum bed power density reached was 1500 W/cu cm at 1500 K. The pressure drop followed the packed-bed correlation, typically 100,000 Pa/cm. The various frit materials used to contain the bed were also tested to 2000 K in helium and hydrogen to determine their properties and reactions with the fuel. Rhenium metal, zirconium carbide, and zirconium oxide appeared to be the best candidate materials, while tungsten and tungsten-rhenium lost mass and strength.

An experimental study of catalytic and non-catalytic reaction in heat recirculating reactors and applications to power generation

NASA Astrophysics Data System (ADS)

Ahn, Jeongmin

An experimental study of the performance of a Swiss roll heat exchanger and reactor was conducted, with emphasis on the extinction limits and comparison of results with and without Pt catalyst. At Re<40, the catalyst was required to sustain reaction; with the catalyst self-sustaining reaction could be obtained at Re less than 1. Both lean and rich extinction limits were extended with the catalyst, though rich limits were extended much further. At low Re, the lean extinction limit was rich of stoichiometric and rich limit had equivalence ratios 80 in some cases. Non-catalytic reaction generally occurred in a flameless mode near the center of the reactor. With or without catalyst, for sufficiently robust conditions, a visible flame would propagate out of the center, but this flame could only be re-centered with catalyst. Gas chromatography indicated that at low Re, CO and non-C3 H8 hydrocarbons did not form. For higher Re, catalytic limits were slightly broader but had much lower limit temperatures. At sufficiently high Re, catalytic and gas-phase limits merged. Experiments with titanium Swiss rolls have demonstrated reducing wall thermal conductivity and thickness leads to lower heat losses and therefore increases operating temperatures and extends flammability limits. By use of Pt catalysts, reaction of propane-air mixtures at temperatures 54°C was sustained. Such low temperatures suggest that polymers may be employed as a reactor material. A polyimide reactor was built and survived prolonged testing at temperatures up to 500°C. Polymer reactors may prove more practical for microscale devices due to their lower thermal conductivity and ease of manufacturing. Since the ultimate goal of current efforts is to develop combustion driven power generation devices at MEMS like scales, a thermally self-sustaining miniature power generation device was developed utilizing a single-chamber solid-oxide-fuel-cell (SOFC) placed in a Swiss roll. With the single-chamber design, fuel/oxygen crossover due to cracking of seals via thermal cycling is irrelevant and coking on the anode is practically eliminated. SOFC power densities up to 420mW/cm2 were observed at low Re. These results suggest that single-chamber SOFC's integrated with heat-recirculating reactors may be a viable approach for small-scale power generation devices.

System Modeling for Ammonia Synthesis Energy Recovery System

NASA Astrophysics Data System (ADS)

Bran Anleu, Gabriela; Kavehpour, Pirouz; Lavine, Adrienne; Ammonia thermochemical Energy Storage Team

2015-11-01

An ammonia thermochemical energy storage system is an alternative solution to the state-of-the-art molten salt TES system for concentrating solar power. Some of the advantages of this emerging technology include its high energy density, no heat losses during the storage duration, and the possibility of long storage periods. Solar energy powers an endothermic reaction to disassociate ammonia into hydrogen and nitrogen, which can be stored for future use. The reverse reaction is carried out in the energy recovery process; a hydrogen-nitrogen mixture flowing through a catalyst bed undergoes the exothermic ammonia synthesis reaction. The goal is to use the ammonia synthesis reaction to heat supercritical steam to temperatures on the order of 650°C as required for a supercritical steam Rankine cycle. The steam will flow through channels in a combined reactor-heat exchanger. A numerical model has been developed to determine the optimal design to heat supercritical steam while maintaining a stable exothermic reaction. The model consists of a transient one dimensional concentric tube counter-flow reactor-heat exchanger. The numerical model determines the inlet mixture conditions needed to achieve various steam outlet conditions.

Optimization of operating parameters for gas-phase photocatalytic splitting of H2S by novel vermiculate packed tubular reactor.

PubMed

Preethi, V; Kanmani, S

2016-10-01

Hydrogen production by gas-phase photocatalytic splitting of Hydrogen Sulphide (H2S) was investigated on four semiconductor photocatalysts including CuGa1.6Fe0.4O2, ZnFe2O3, (CdS + ZnS)/Fe2O3 and Ce/TiO2. The CdS and ZnS coated core shell particles (CdS + ZnS)/Fe2O3 shows the highest rate of hydrogen (H2) production under optimized conditions. Packed bed tubular reactor was used to study the performance of prepared photocatalysts. Selection of the best packing material is a key for maximum removal efficiency. Cheap, lightweight and easily adsorbing vermiculate materials were used as a novel packing material and were found to be effective in splitting H2S. Effect of various operating parameters like flow rate, sulphide concentration, catalyst dosage, light irradiation were tested and optimized for maximum H2 conversion of 92% from industrial waste H2S. Copyright © 2016 Elsevier Ltd. All rights reserved.

A new photocatalytic reactor for trace contaminant control: a water polishing system.

PubMed

Gonzalez-Martin, A; Kim, J; Van Hyfte, J; Rutherford, L A; Andrews, C

2001-01-01

In spacecraft water recovery systems there is a need to develop a postprocessor water polishing system to remove organic impurities to levels below 250 micrograms/L (ppb) with a minimum use of expendables. This article addresses the development of a photocatalytic process as a postprocessor water polishing system that is microgravity compatible, operates at room temperature, and requires only a minimal use of both oxygen gas (or air) and electrical power for low energy UV-A (315-400 nm) lamps. In the photocatalytic process, organic contaminants are degraded to benign end products on semiconductor surfaces, usually TiO2. Some challenging issues related to the use of TiO2 for the degradation of organic contaminants have been addressed. These include: i) efficient and stable catalytic material; ii) immobilization of the catalyst to produce a high surface area material that can be used in packed-bed reactors, iii) effective light penetration, iv) effective, microgravity-compatible, oxidant delivery; v) reduced pressure drop, and vi) minimum retention time. The research and development performed on this photocatalytic process is presented in detail. Grant numbers: NAS9-97182.

On-line regeneration of hydrodesulfurization catalyst

DOEpatents

Preston, Jr., John L.

1980-01-01

A hydrotreating catalyst is regenerated as it concurrently hydrotreats a hydrocarbon fuel by introducing a low concentration of oxygen into the catalyst bed either continuously or periodically. At low oxygen concentrations the carbon deposits on the catalyst are burned off without harming the catalyst and without significantly affecting the hydrotreating process. In a preferred embodiment the hydrotreating process is hydrodesulfurization, and regenerating is done periodically with oxygen concentrations between 0.1 and 0.5 volume percent.

Safety considerations in testing a fuel-rich aeropropulsion gas generator

NASA Technical Reports Server (NTRS)

Rollbuhler, R. James; Hulligan, David D.

1991-01-01

A catalyst containing reactor is being tested using a fuel-rich mixture of Jet A fuel and hot input air. The reactor product is a gaseous fuel that can be utilized in aeropropulsion gas turbine engines. Because the catalyst material is susceptible to damage from high temperature conditions, fuel-rich operating conditions are attained by introducing the fuel first into an inert gas stream in the reactor and then displacing the inert gas with reaction air. Once a desired fuel-to-air ratio is attained, only limited time is allowed for a catalyst induced reaction to occur; otherwise the inert gas is substituted for the air and the fuel flow is terminated. Because there presently is not a gas turbine combustor in which to burn the reactor product gas, the gas is combusted at the outlet of the test facility flare stack. This technique in operations has worked successfully in over 200 tests.

Production of edible carbohydrates from formaldehyde in a spacecraft. pH variations in the calcium hydroxide catalyzed formose reaction. Final Report, 1 Jul. 1973 - 30 Jun. 1974. M.S. Thesis

NASA Technical Reports Server (NTRS)

Weiss, A. H.; Kohler, J. T.; John, T.

1974-01-01

The study of the calcium hydroxide catalyzed condensation of formaldehyde was extended to a batch reactor system. Decreases in pH were observed, often in the acid regime, when using this basic catalyst. This observation was shown to be similar to results obtained by others using less basic catalysts in the batch mode. The relative rates of these reactions are different in a batch reactor than in a continuous stirred tank reactor. This difference in relative rates is due to the fact that at any degree of advancement in the batch system, the products have a history of previous products, pH, and dissolved catalyst. The relative rate differences can be expected to yield a different nature of product sugars for the two types of reactors.

Evaluation of the effectiveness factor along immobilized enzyme fixed-bed reactors: design of a reactor with naringinase covalently immobilized into glycophase-coated porous glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manjon, A.; Iborra, J.L.; Gomez, J.L.

A design equation is presented for packed-bed reactors containing immobilized enzymes in spherical porous particles with internal diffusion effects and obeying reversible one-intermediate Michaelis-Menten kinetics. The equation is also able to explain irreversible and competitive product inhibition kinetics. It allows the axial substrate profiles to be calculated and the dependence of the effectiveness factor along the reactor length to be continuously evaluated. The design equation was applied to explain the behavior of naringinase immobilized in Glycophase-coated porous glass operating in a packed-bed reactor and hydrolyzing both p-nitrophenyl-alpha-L-rhamnoside and naringin. The theoretically predicted results were found to fit well with experimentallymore » measured values. (Refs. 28).« less

Generation and Reduction of NOx on Air-Fed Ozonizers

NASA Astrophysics Data System (ADS)

Ehara, Yoshiyasu; Amemiya, Yusuke; Yamamoto, Toshiaki

A generation and reduction of NOx on air-fed ozonizers using a ferroelectric packed bed reactor have been experimentally investigated. The reactors packed with CaTiO3, SrTiO3 and BaTiO3 pellets are examined for ozone generation. An ac voltage is applied to the reactor to generate partial discharge. Ozone concentration and the different nitrogen oxides at downstream of the packed bed reactor were measured with UV absorption ozone monitor and a Fourier transform infrared spectroscope respectively. The dielectric constant of packed ferroelectric pellets influences the discharge characteristic, ozone and NOx generations are varied by the dielectric constant value. Focusing on a discharge pulse current and maximum discharge magnitude, the ferroelectric packed bed plasma reactors have been evaluated on nitrogen oxide and ozone generated concentrations.

Batch Tests To Determine Activity Distribution and Kinetic Parameters for Acetate Utilization in Expanded-Bed Anaerobic Reactors

PubMed Central

Fox, Peter; Suidan, Makram T.

1990-01-01

Batch tests to measure maximum acetate utilization rates were used to determine the distribution of acetate utilizers in expanded-bed sand and expanded-bed granular activated carbon (GAC) reactors. The reactors were fed a mixture of acetate and 3-ethylphenol, and they contained the same predominant aceticlastic methanogen, Methanothrix sp. Batch tests were performed both on the entire reactor contents and with media removed from the reactors. Results indicated that activity was evenly distributed within the GAC reactors, whereas in the sand reactor a sludge blanket on top of the sand bed contained approximately 50% of the activity. The Monod half-velocity constant (Ks) for the acetate-utilizing methanogens in two expanded-bed GAC reactors was searched for by combining steady-state results with batch test data. All parameters necessary to develop a model with Monod kinetics were experimentally determined except for Ks. However, Ks was a function of the effluent 3-ethylphenol concentration, and batch test results demonstrated that maximum acetate utilization rates were not a function of the effluent 3-ethylphenol concentration. Addition of a competitive inhibition term into the Monod expression predicted the dependence of Ks on the effluent 3-ethylphenol concentration. A two-parameter search determined a Ks of 8.99 mg of acetate per liter and a Ki of 2.41 mg of 3-ethylphenol per liter. Model predictions were in agreement with experimental observations for all effluent 3-ethylphenol concentrations. Batch tests measured the activity for a specific substrate and determined the distribution of activity in the reactor. The use of steady-state data in conjunction with batch test results reduced the number of unknown kinetic parameters and thereby reduced the uncertainty in the results and the assumptions made. PMID:16348175

Batch tests to determine activity distribution and kinetic parameters for acetate utilization in expanded-bed anaerobic reactors.

PubMed

Fox, P; Suidan, M T

1990-04-01

Batch tests to measure maximum acetate utilization rates were used to determine the distribution of acetate utilizers in expanded-bed sand and expanded-bed granular activated carbon (GAC) reactors. The reactors were fed a mixture of acetate and 3-ethylphenol, and they contained the same predominant aceticlastic methanogen, Methanothrix sp. Batch tests were performed both on the entire reactor contents and with media removed from the reactors. Results indicated that activity was evenly distributed within the GAC reactors, whereas in the sand reactor a sludge blanket on top of the sand bed contained approximately 50% of the activity. The Monod half-velocity constant (K(s)) for the acetate-utilizing methanogens in two expanded-bed GAC reactors was searched for by combining steady-state results with batch test data. All parameters necessary to develop a model with Monod kinetics were experimentally determined except for K(s). However, K(s) was a function of the effluent 3-ethylphenol concentration, and batch test results demonstrated that maximum acetate utilization rates were not a function of the effluent 3-ethylphenol concentration. Addition of a competitive inhibition term into the Monod expression predicted the dependence of K(s) on the effluent 3-ethylphenol concentration. A two-parameter search determined a K(s) of 8.99 mg of acetate per liter and a K(i) of 2.41 mg of 3-ethylphenol per liter. Model predictions were in agreement with experimental observations for all effluent 3-ethylphenol concentrations. Batch tests measured the activity for a specific substrate and determined the distribution of activity in the reactor. The use of steady-state data in conjunction with batch test results reduced the number of unknown kinetic parameters and thereby reduced the uncertainty in the results and the assumptions made.

Flash hydrogenation of coal

DOEpatents

Manowitz, Bernard; Steinberg, Meyer; Sheehan, Thomas V.; Winsche, Warren E.; Raseman, Chad J.

1976-01-01

A process for the hydrogenation of coal comprising the contacting of powdered coal with hydrogen in a rotating fluidized bed reactor. A rotating fluidized bed reactor suitable for use in this process is also disclosed. The coal residence time in the reactor is limited to less than 5 seconds while the hydrogen contact time is not in excess of 0.2 seconds.

Indirect Liquefaction of Coal-Biomass Mixture for Production of Jet Fuel with High Productivity and Selectivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gangwal, Santosh K; McCabe, Kevin

Coal to liquids (CTL) and coal-biomass to liquids (CBTL) processes were advanced by testing and demonstrating Southern Research’s sulfur tolerant nickel-based reforming catalyst and Chevron’s highly selective and active cobalt-zeolite hybrid Fischer-Tropsch (FT) catalyst to clean, upgrade and convert syngas predominantly to jet fuel range hydrocarbon liquids, thereby minimizing expensive cleanup and wax upgrading operations. The National Carbon Capture Center (NCCC) operated by Southern Company (SC) at Wilsonville, Alabama served as the host site for the gasifier slip-stream and simulated syngas testing/demonstration. Reformer testing was performed to (1) reform tar and light hydrocarbons, (2) decompose ammonia in the presence H2S,more » and (3) deliver the required H2 to CO ratio for FT synthesis. FT Testing was performed to produce a product primarily containing C5-C20 liquid hydrocarbons and no C21+ waxy hydrocarbons with productivity greater than 0.7 gC5+/g catalyst/h, and at least 70% diesel and jet fuel range (C8-C20) hydrocarbon selectivity in the liquid product. A novel heat-exchange reactor system was employed to enable the use of the highly active FT catalyst and larger diameter reactors that results in cost reduction for commercial systems. Following laboratory development and testing, SR’s laboratory reformer was modified to operate in a Class 1 Div. 2 environment, installed at NCCC, and successfully tested for 125 hours using raw syngas. The catalyst demonstrated near equilibrium reforming (~90%) of methane and complete reforming/decomposition of tar and ammonia in the presence of up to 380 ppm H2S. For FT synthesis, SR modified and utilized a bench scale skid mounted FT reactor system (SR-CBTL test rig) that was fully integrated with a slip stream from SC/NCCC’s transport gasifier (TRIG). The test-rig developed in a previous project (DE-FE0010231) was modified to receive up to 7.5 lb/h raw syngas augmented with bottled syngas to adjust the H2/CO molar ratio to 2, clean it to cobalt FT catalyst specifications, and produce liquid FT products at the design capacity of up to 6 L/day. Promising Chevron catalyst candidates in the size range from 70-200 μm were loaded onto SR’s 2-inch ID and 4-inch ID bench-scale reactors utilizing IntraMicron’s micro-fiber entrapped catalyst (MFEC) heat exchange reactor technology. During 2 test campaigns, the FT reactors were successfully demonstrated at NCCC using syngas for ~420 hours. The catalyst did not experience deactivation during the tests. SR’s thermo-syphon heat removal system maintained reactor operating temperature along the axis to within ±4 °C. The experiments gave a steady catalyst productivity of 0.7-0.8 g/g catalyst/h, liquid hydrocarbon selectivity of ~75%, and diesel and jet fuel range hydrocarbon selectivity in the liquid product as high as 85% depending on process conditions. A preliminary techno-economic evaluation showed that the SR technology-based 50,000 bpd plant had a 10 % lower total plant cost compared to a conventional slurry reactor based plant. Furthermore, because of the modular nature of the SR technology, it was shown that the total plant cost advantage increases to >35 % as the plant is scaled down to 1000 bpd.« less

Application of a fluidized bed reactor charged with aragonite for control of alkalinity, pH and carbon dioxide in marine recirculating aquaculture systems

USGS Publications Warehouse

Paul S Wills, PhD; Pfeiffer, Timothy; Baptiste, Richard; Watten, Barnaby J.

2016-01-01

Control of alkalinity, dissolved carbon dioxide (dCO2), and pH are critical in marine recirculating aquaculture systems (RAS) in order to maintain health and maximize growth. A small-scale prototype aragonite sand filled fluidized bed reactor was tested under varying conditions of alkalinity and dCO2 to develop and model the response of dCO2 across the reactor. A large-scale reactor was then incorporated into an operating marine recirculating aquaculture system to observe the reactor as the system moved toward equilibrium. The relationship between alkalinity dCO2, and pH across the reactor are described by multiple regression equations. The change in dCO2 across the small-scale reactor indicated a strong likelihood that an equilibrium alkalinity would be maintained by using a fluidized bed aragonite reactor. The large-scale reactor verified this observation and established equilibrium at an alkalinity of approximately 135 mg/L as CaCO3, dCO2 of 9 mg/L, and a pH of 7.0 within 4 days that was stable during a 14 day test period. The fluidized bed aragonite reactor has the potential to simplify alkalinity and pH control, and aid in dCO2 control in RAS design and operation. Aragonite sand, purchased in bulk, is less expensive than sodium bicarbonate and could reduce overall operating production costs.

Treatment of synthetic refinery wastewater in anoxic-aerobic sequential moving bed reactors and sulphur recovery.

PubMed

Mallick, Subrat Kumar; Chakraborty, Saswati

2017-11-10

Objective of the present study was to simultaneously biodegrade synthetic petroleum refinery wastewater containing phenol (750 mg/L), sulphide (750 mg/L), hydrocarbon (as emulsified diesel of 300 mg/L), ammonia-nitrogen (350 mg/L) at pH >9 in anoxic-aerobic sequential moving bed reactors. The optimum mixing speed of anoxic reactor was observed at 20 rpm and beyond that, removal rate remained constant. In anoxic reactor the minimum hydraulic retention time was observed to be 2 days for complete removal of sulphide, 40-50% removal of phenol and total hydrocarbons and 52% of sulphur recovery. The optimum HRT of aerobic moving bed reactor was observed as 16 h (total HRT of 64 h for anoxic and aerobic reactors) for complete removals of phenol, total hydrocarbons, COD (chemical oxygen demand) and ammonia-nitrogen with nitrification.

Fluidized bed silicon deposition from silane

NASA Technical Reports Server (NTRS)

Hsu, George C. (Inventor); Levin, Harry (Inventor); Hogle, Richard A. (Inventor); Praturi, Ananda (Inventor); Lutwack, Ralph (Inventor)

1982-01-01

A process and apparatus for thermally decomposing silicon containing gas for deposition on fluidized nucleating silicon seed particles is disclosed. Silicon seed particles are produced in a secondary fluidized reactor by thermal decomposition of a silicon containing gas. The thermally produced silicon seed particles are then introduced into a primary fluidized bed reactor to form a fluidized bed. Silicon containing gas is introduced into the primary reactor where it is thermally decomposed and deposited on the fluidized silicon seed particles. Silicon seed particles having the desired amount of thermally decomposed silicon product thereon are removed from the primary fluidized reactor as ultra pure silicon product. An apparatus for carrying out this process is also disclosed.

Fluidized bed silicon deposition from silane

NASA Technical Reports Server (NTRS)

Hsu, George (Inventor); Levin, Harry (Inventor); Hogle, Richard A. (Inventor); Praturi, Ananda (Inventor); Lutwack, Ralph (Inventor)

1984-01-01

A process and apparatus for thermally decomposing silicon containing gas for deposition on fluidized nucleating silicon seed particles is disclosed. Silicon seed particles are produced in a secondary fluidized reactor by thermal decomposition of a silicon containing gas. The thermally produced silicon seed particles are then introduced into a primary fluidized bed reactor to form a fludized bed. Silicon containing gas is introduced into the primary reactor where it is thermally decomposed and deposited on the fluidized silicon seed particles. Silicon seed particles having the desired amount of thermally decomposed silicon product thereon are removed from the primary fluidized reactor as ultra pure silicon product. An apparatus for carrying out this process is also disclosed.

Effect of bed characters on the direct synthesis of dimethyldichlorosilane in fluidized bed reactor.

PubMed

Zhang, Pan; Duan, Ji H; Chen, Guang H; Wang, Wei W

2015-03-06

This paper presents the numerical investigation of the effects of the general bed characteristics such as superficial gas velocities, bed temperature, bed heights and particle size, on the direct synthesis in a 3D fluidized bed reactor. A 3D model for the gas flow, heat transfer, and mass transfer was coupled to the direct synthesis reaction mechanism verified in the literature. The model was verified by comparing the simulated reaction rate and dimethyldichlorosilane (M2) selectivity with the experimental data in the open literature and real production data. Computed results indicate that superficial gas velocities, bed temperature, bed heights, and particle size have vital effect on the reaction rates and/or M2 selectivity.

Effect of Bed Characters on the Direct Synthesis of Dimethyldichlorosilane in Fluidized Bed Reactor

PubMed Central

Zhang, Pan; Duan, Ji H.; Chen, Guang H.; Wang, Wei W.

2015-01-01

This paper presents the numerical investigation of the effects of the general bed characteristics such as superficial gas velocities, bed temperature, bed heights and particle size, on the direct synthesis in a 3D fluidized bed reactor. A 3D model for the gas flow, heat transfer, and mass transfer was coupled to the direct synthesis reaction mechanism verified in the literature. The model was verified by comparing the simulated reaction rate and dimethyldichlorosilane (M2) selectivity with the experimental data in the open literature and real production data. Computed results indicate that superficial gas velocities, bed temperature, bed heights, and particle size have vital effect on the reaction rates and/or M2 selectivity. PMID:25742729

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

During this time period, at WVU, we tried several methods to eliminate problems related to condensation of heavier products when reduced Mo-Ni-K/C materials were used as catalysts. We then resumed our kinetic study on the reduced Mo-Ni-K/C catalysts. We have also obtained same preliminary results in our attempts to analyze quantitatively the temperature-programmed reduction (TPR) spectra for C-supported Mo-based catalysts. We have completed the kinetic study for the sulfided Co-K-MoS /C catalyst. We have compared the results of methanol synthesis 2 using the membrane reactor with those using a simple plug-flow reactor. At UCC, the complete characterization of selected catalystsmore » has been completed. The results suggest that catalyst pretreatment under different reducing conditions yield different surface compositions and thus different catalytic reactivities.« less

Epoxidation catalyst and process

DOEpatents

Linic, Suljo; Christopher, Phillip

2010-10-26

Disclosed herein is a catalytic method of converting alkenes to epoxides. This method generally includes reacting alkenes with oxygen in the presence of a specific silver catalyst under conditions suitable to produce a yield of the epoxides. The specific silver catalyst is a silver nanocrystal having a plurality of surface planes, a substantial portion of which is defined by Miller indices of (100). The reaction is performed by charging a suitable reactor with this silver catalyst and then feeding the reactants to the reactor under conditions to carry out the reaction. The reaction may be performed in batch, or as a continuous process that employs a recycle of any unreacted alkenes. The specific silver catalyst has unexpectedly high selectivity for epoxide products. Consequently, this general method (and its various embodiments) will result in extraordinarily high epoxide yields heretofore unattainable.

Simultaneous production of oil enriched in ω-3 polyunsaturated fatty acids and biodiesel from fish wastes.

PubMed

Enascuta, Cristina Emanuela; Stepan, Emil; Bolocan, Ion; Bombos, Dorin; Calin, Catalina; Oprescu, Elena-Emilia; Lavric, Vasile

2018-05-01

The waste resulted from fish processing industries are discarded into the environment around the world, causing environmental pollution. The main problem of fish oil extracted from waste is the high content in free fatty acids (FFA) which decrease the yield in fatty acids esters during transesterification reactions. Therefore, to correct the fish-oil properties, a new environmentally friendly heterogeneous superacid catalyst (SO 4 2- /SnO 2 -ZrO 2 ) was tested in the esterification reaction of FFA with ethanol. The catalyst was characterized by different techniques (XRD, FT-IR, FT-IR of adsorbed pyridine, BET, SEM-EDX, TGA and acidity measurements). The reaction was found to follow a Langmuir-Hinshelwood (L-H) dual-site mechanism with the novelty that both Brönsted and Lewis acid centers participate equally in the esterification reaction. The pre-treated oil was subjected to transesterification reaction with ethanol over a heterogeneous base catalyst and then, the saturated and unsaturated fractions of fatty acid ethyl esters (FAEE) were separated using a vacuum rectification unit with falling film. The saturated content can be used as biofuel, while the unsaturated FAEE are further transesterified with glycerol in order to obtain oil with high content in polyunsaturated fatty acids (PUFA). A detailed study of the intrinsic kinetic process at the surface of the superacid catalyst and a thorough mathematical model of the fixed bed reactor were written and validated by an experimental program, designed according to the D-optimal methodology. Copyright © 2018 Elsevier Ltd. All rights reserved.

Design of a laboratory scale fluidized bed reactor

NASA Astrophysics Data System (ADS)

Wikström, E.; Andersson, P.; Marklund, S.

1998-04-01

The aim of this project was to construct a laboratory scale fluidized bed reactor that simulates the behavior of full scale municipal solid waste combustors. The design of this reactor is thoroughly described. The size of the laboratory scale fluidized bed reactor is 5 kW, which corresponds to a fuel-feeding rate of approximately 1 kg/h. The reactor system consists of four parts: a bed section, a freeboard section, a convector (postcombustion zone), and an air pollution control (APC) device system. The inside diameter of the reactor is 100 mm at the bed section and it widens to 200 mm in diameter in the freeboard section; the total height of the reactor is 1760 mm. The convector part consists of five identical sections; each section is 2700 mm long and has an inside diameter of 44.3 mm. The reactor is flexible regarding the placement and number of sampling ports. At the beginning of the first convector unit and at the end of each unit there are sampling ports for organic micropollutants (OMP). This makes it possible to study the composition of the flue gases at various residence times. Sampling ports for inorganic compounds and particulate matter are also placed in the convector section. All operating parameters, reactor temperatures, concentrations of CO, CO2, O2, SO2, NO, and NO2 are continuously measured and stored at selected intervals for further evaluation. These unique features enable full control over the fuel feed, air flows, and air distribution as well as over the temperature profile. Elaborate details are provided regarding the configuration of the fuel-feeding systems, the fluidized bed, the convector section, and the APC device. This laboratory reactor enables detailed studies of the formation mechanisms of OMP, such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), poly-chlorinated biphenyls (PCBs), and polychlorinated benzenes (PCBzs). With this system formation mechanisms of OMP occurring in both the combustion and postcombustion zones can be studied. Other advantages are memory effect minimization and the reduction of experimental costs compared to full scale combustors. Comparison of the combustion parameters and emission data from this 5 kW laboratory scale reactor with full scale combustors shows good agreement regarding emission levels and PCDD/PCDF congener patterns. This indicates that the important formation and degradation reactions of OMP in the reactor are the same formation mechanisms as in full scale combustors.

Silica-Supported Catalyst for Enantioselective Arylation of Aldehydes under Batch and Continuous-Flow Conditions.

PubMed

Watanabe, Satoshi; Nakaya, Naoyuki; Akai, Junichiro; Kanaori, Kenji; Harada, Toshiro

2018-05-04

A silica-supported 3-aryl H 8 -BINOL-derived titanium catalyst exhibited high performance in the enantioselective arylation of aromatic aldehydes using Grignard and organolithium reagents not only under batch conditions but also under continuous-flow conditions. Even with a simple pipet reactor packed with the heterogeneous catalyst, the enantioselective production of chiral diarylmethanols could be achieved through a continuous introduction of aldehydes and mixed titanium reagents generated from the organometallic precursors. The pipet reactor could be used repeatedly in different reactions without appreciable deterioration of the activity.

Anaerobic treatment of winery wastewater in fixed bed reactors.

PubMed

Ganesh, Rangaraj; Rajinikanth, Rajagopal; Thanikal, Joseph V; Ramanujam, Ramamoorty Alwar; Torrijos, Michel

2010-06-01

The treatment of winery wastewater in three upflow anaerobic fixed-bed reactors (S9, S30 and S40) with low density floating supports of varying size and specific surface area was investigated. A maximum OLR of 42 g/l day with 80 +/- 0.5% removal efficiency was attained in S9, which had supports with the highest specific surface area. It was found that the efficiency of the reactors increased with decrease in size and increase in specific surface area of the support media. Total biomass accumulation in the reactors was also found to vary as a function of specific surface area and size of the support medium. The Stover-Kincannon kinetic model predicted satisfactorily the performance of the reactors. The maximum removal rate constant (U(max)) was 161.3, 99.0 and 77.5 g/l day and the saturation value constant (K(B)) was 162.0, 99.5 and 78.0 g/l day for S9, S30 and S40, respectively. Due to their higher biomass retention potential, the supports used in this study offer great promise as media in anaerobic fixed bed reactors. Anaerobic fixed-bed reactors with these supports can be applied as high-rate systems for the treatment of large volumes of wastewaters typically containing readily biodegradable organics, such as the winery wastewater.

Pressurized fluidized bed reactor and a method of operating the same

DOEpatents

Isaksson, J.

1996-02-20

A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine. 1 fig.

Pressurized fluidized bed reactor and a method of operating the same

DOEpatents

Isaksson, Juhani

1996-01-01

A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine.

Partial nitritation of raw anaerobic sludge digester liquor by swim-bed and swim-bed activated sludge processes and comparison of their sludge characteristics.

PubMed

Qiao, Sen; Kawakubo, Yuki; Koyama, Toichiro; Furukawa, Kenji

2008-11-01

This study evaluated performance of swim-bed (SB) reactors packed with a novel acrylic fiber carrier (BF) and swim-bed activated sludge (SBAS) reactor for partial nitritation of anaerobic sludge digester liquor from a municipal wastewater treatment plant. Comparison of characteristics of sludge obtained from both the reactors was also made. The average conversion rates of ammonium to nitrite were 52.3% and 40.0% under relatively high nitrogen loading rates over 3.0 kg-N/m(3)/d, respectively in two reactors. The average BOD(5) removal efficiencies were 74.3% and 64.4%, respectively in the two reactors. The size of the sludge pellets taken from SB and SBAS reactors was found to be approximately three times (229 mum versus 88 mum) of that of the seed sludge. This sludge also had relatively high extracellular proteins levels indicating better sludge settling capability as compared to the sludge taken from SBAS reactor. Although the effluent nitrite/ammonium ratios had fluctuated in both reactor in some extent, the low dissolved oxygen concentration (average of 2.5 versus 0.35 mg/l), low suspended solids (average of 33.3 versus 33.5 mg/l), and about 50% ammonium conversion to nitrite demonstrated the application potential of anammox process for nitrogen removal.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amitava Sarkar; James K. Neathery; Burtron H. Davis

A fundamental filtration study was started to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. Slurry-phase FTS in slurry bubble column reactor systems is the preferred mode of operation since the reaction is highly exothermic. Consequently, heavy wax products in one approach may be separated from catalyst particles before being removed from the reactor system. Achieving an efficient wax product separation from iron-based catalysts is one of the most challenging technical problems associated with slurry-phase iron-based FTS and is a key factor for optimizing operating costs. The separation problem is further compounded by attrition of ironmore » catalyst particles and the formation of ultra-fine particles.« less

Catalytic Reactor For Oxidizing Mercury Vapor

DOEpatents

Helfritch, Dennis J.

1998-07-28

A catalytic reactor (10) for oxidizing elemental mercury contained in flue gas is provided. The catalyst reactor (10) comprises within a flue gas conduit a perforated corona discharge plate (30a, b) having a plurality of through openings (33) and a plurality of projecting corona discharge electrodes (31); a perforated electrode plate (40a, b, c) having a plurality of through openings (43) axially aligned with the through openings (33) of the perforated corona discharge plate (30a, b) displaced from and opposing the tips of the corona discharge electrodes (31); and a catalyst member (60a, b, c, d) overlaying that face of the perforated electrode plate (40a, b, c) opposing the tips of the corona discharge electrodes (31). A uniformly distributed corona discharge plasma (1000) is intermittently generated between the plurality of corona discharge electrode tips (31) and the catalyst member (60a, b, c, d) when a stream of flue gas is passed through the conduit. During those periods when corona discharge (1000) is not being generated, the catalyst molecules of the catalyst member (60a, b, c, d) adsorb mercury vapor contained in the passing flue gas. During those periods when corona discharge (1000) is being generated, ions and active radicals contained in the generated corona discharge plasma (1000) desorb the mercury from the catalyst molecules of the catalyst member (60a, b, c, d), oxidizing the mercury in virtually simultaneous manner. The desorption process regenerates and activates the catalyst member molecules.

40 CFR 65.162 - Nonflare control and recovery device monitoring records.

Code of Federal Regulations, 2010 CFR

2010-07-01

...). For catalytic incinerators, record the daily average of the temperature upstream of the catalyst bed and the daily average of the temperature differential across the bed. For halogen scrubbers, record... regeneration stream flow and carbon bed regeneration temperature are monitored, the following records shall be...

Run 263 with Black Thunder Mine subbituminous coal and dispersed molybdenum catalysts. Technical progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This report presents the results of Run 263 performed at the Advanced Coal Liquefaction R&D Facility in Wilsonville, Alabama. The run started on October 31, 1991 and continued until February 23, 1992. Tests were conducted by operating the reactors in the Close-Coupled Integrated Two-Stage Liquefaction mode and by processing Black Thunder Mine subbituminous coal from Wyodak-Anderson seam in Wyoming Powder River Basin. Half volume reactors were used for the entire run. In the first part of Run 263, a dispersed molybdenum catalyst was evaluated for its performance without a supported catalyst in the second stage. Molyvan L and Molyvan 822more » (commercially available as friction reducing lubricants) were used as precursors for the dispersed molybdenum catalyst. The effect of the dispersed catalyst on eliminating the solids buildup was also evaluated. For the second part of the run, the hybrid catalyst system was tested with supported Criterion 324 1/1611 catalyst in the second stage at catalyst replacement rates of 2 and 3 lb/ton of MF coal. The molybdenum concentration was 100--200 ppm based on MF coal. Iron oxide was used as a slurry catalyst precursor at a rate of 1--2 wt % MF coal throughout the run with dimethyl disulfide (DMDS) as the sulfiding agent. The close-coupled reactor unit was on-stream for 2482 hours for an on-stream factor of 91.2% and the ROSE-SR{sup sm} unit was on-feed for 2126 hours for an on-stream factor of 96.4% for the entire run.« less

Run 263 with Black Thunder Mine subbituminous coal and dispersed molybdenum catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This report presents the results of Run 263 performed at the Advanced Coal Liquefaction R D Facility in Wilsonville, Alabama. The run started on October 31, 1991 and continued until February 23, 1992. Tests were conducted by operating the reactors in the Close-Coupled Integrated Two-Stage Liquefaction mode and by processing Black Thunder Mine subbituminous coal from Wyodak-Anderson seam in Wyoming Powder River Basin. Half volume reactors were used for the entire run. In the first part of Run 263, a dispersed molybdenum catalyst was evaluated for its performance without a supported catalyst in the second stage. Molyvan L and Molyvanmore » 822 (commercially available as friction reducing lubricants) were used as precursors for the dispersed molybdenum catalyst. The effect of the dispersed catalyst on eliminating the solids buildup was also evaluated. For the second part of the run, the hybrid catalyst system was tested with supported Criterion 324 1/1611 catalyst in the second stage at catalyst replacement rates of 2 and 3 lb/ton of MF coal. The molybdenum concentration was 100--200 ppm based on MF coal. Iron oxide was used as a slurry catalyst precursor at a rate of 1--2 wt % MF coal throughout the run with dimethyl disulfide (DMDS) as the sulfiding agent. The close-coupled reactor unit was on-stream for 2482 hours for an on-stream factor of 91.2% and the ROSE-SR[sup sm] unit was on-feed for 2126 hours for an on-stream factor of 96.4% for the entire run.« less

Separation of catalyst from Fischer-Tropsch slurry

DOEpatents

White, C.M.; Quiring, M.S.; Jensen, K.L.; Hickey, R.F.; Gillham, L.D.

1998-10-27

In a catalytic process for converting synthesis gas including hydrogen and carbon monoxide to hydrocarbons and oxygenates by a slurry Fischer-Tropsch synthesis, the wax product along with dispersed catalyst is removed from the slurry and purified by removing substantially all of the catalyst prior to upgrading the wax and returning a portion to the Fischer-Tropsch reaction. Separation of the catalyst particles from the wax product is accomplished by dense gas and/or liquid extraction in which the organic compounds in the wax are dissolved and carried away from the insoluble inorganic catalyst particles that are primarily inorganic in nature. The purified catalyst-free wax product can be subsequently upgraded by various methods such as hydrogenation, isomerization, hydrocracking, conversion to gasoline and other products over ZSM-5 aluminosilicate zeolite, etc. The catalyst particles are returned to the Fischer-Tropsch Reactor by mixing them with a wax fraction of appropriate molecular weight, boiling point and viscosity to avoid reactor gelation. 2 figs.

Two stages catalytic pyrolysis of refuse derived fuel: production of biofuel via syncrude.

PubMed

Miskolczi, N; Buyong, F; Angyal, A; Williams, P T; Bartha, L

2010-11-01

Thermo-catalytic pyrolysis of refuse derived fuels with different catalysts had been conducted in a two stages process due to its important potential value as fuel. The first stage was a pure thermal pyrolysis in a horizontal tubular reactor with feed rate of 0.5kg hourly. The second stage was a semi-batch process in the presence of catalysts. Results showed that the tested catalysts significantly have affected the quantity of products. E.g. gas yield could be increased with 350% related to the catalyst free case using ZSM-5, while that of pyrolytic oil was 115% over Y-zeolite. Gases consisted of mainly CO and CO(2) obtained from the tubular reactor, while dominantly hydrocarbons from the second stage. Ni-Mo-catalyst and Co-Mo-catalyst had shown activity in pyrolytic oil upgrading via in-situ hydrogenation-dehydrogenation reactions. Sulphur, nitrogen and chlorine level in pyrolytic oils could be significantly declined by using of catalysts.

Comparison of the decomposition characteristics of aromatic VOCs using an electron beam hybrid system

NASA Astrophysics Data System (ADS)

Son, Youn-Suk; Kim, Ki-Joon; Kim, Ji-Yong; Kim, Jo-Chun

2010-12-01

We applied a hybrid technique to assess the decomposition characteristics of ethylbenzene and toluene that annexed the catalyst technique with existing electron beam (EB) technology. The removal efficiency of ethylbenzene in the EB-catalyst hybrid turned out to be 30% greater than that of EB-only treatment. We concluded that ethylbenzene was decomposed more easily than toluene by EB irradiation. We compared the independent effects of the EB-catalyst hybrid and catalyst-only methods, and observed that the efficiency of the EB-catalyst hybrid demonstrated approximately 6% improvement for decomposing toluene and 20% improvement for decomposing ethylbenzene. The G-values for ethylbenzene increased with initial concentration and reactor type: for example, the G-values by reactor type at 2800 ppmC were 7.5-10.9 (EB-only) and 12.9-25.7 (EB-catalyst hybrid). We also observed a significant decrease in by-products as well as in the removal efficiencies associated with the EB-catalyst hybrid technique.

Method For Reactivating Solid Catalysts Used For Alklation Reactions

DOEpatents

Ginosar, Daniel M.; Thompson, David N.; Coates, Kyle; Zalewski, David J.; Fox, Robert V.

2005-05-03

A method for reactivating a solid alkylation catalyst is provided which can be performed within a reactor that contains the alkylation catalyst or outside the reactor. Effective catalyst reactivation is achieved whether the catalyst is completely deactivated or partially deactivated. A fluid reactivating agent is employed to dissolve catalyst fouling agents and also to react with such agents and carry away the reaction products. The deactivated catalyst is contacted with the fluid reactivating agent under pressure and temperature conditions such that the fluid reactivating agent is dense enough to effectively dissolve the fouling agents and any reaction products of the fouling agents and the reactivating agent. Useful pressures and temperatures for reactivation include near-critical, critical, and supercritical pressures and temperatures for the reactivating agent. The fluid reactivating agent can include, for example, a branched paraffin containing at least one tertiary carbon atom, or a compound that can be isomerized to a molecule containing at least one tertiary carbon atom.

Method for reactivating solid catalysts used in alkylation reactions

DOEpatents

Ginosar, Daniel M.; Thompson, David N.; Coates, Kyle; Zalewski, David J.; Fox, Robert V.

2003-06-17

A method for reactivating a solid alkylation catalyst is provided which can be performed within a reactor that contains the alkylation catalyst or outside the reactor. Effective catalyst reactivation is achieved whether the catalyst is completely deactivated or partially deactivated. A fluid reactivating agent is employed to dissolve catalyst fouling agents and also to react with such agents and carry away the reaction products. The deactivated catalyst is contacted with the fluid reactivating agent under pressure and temperature conditions such that the fluid reactivating agent is dense enough to effectively dissolve the fouling agents and any reaction products of the fouling agents and the reactivating agent. Useful pressures and temperatures for reactivation include near-critical, critical, and supercritical pressures and temperatures for the reactivating agent. The fluid reactivating agent can include, for example, a branched paraffin containing at least one tertiary carbon atom, or a compound that can be isomerized to a molecule containing at least one tertiary carbon atom.

Advanced Coal Liquefaction Research and Development Facility, Wilsonville, Alabama. Run 262 with Black Thunder subbituminous coal: Technical progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This report presents the results of Run 262 performed at the Advanced Coal Liquefaction R&D Facility in Wilsonville, Alabama. The run started on July 10, 1991 and continued until September 30, 1991, operating in the Close-Coupled Integrated Two-Stage Liquefaction mode processing Black Thunder Mine subbituminous coal (Wyodak-Anderson seam from Wyoming Powder River Basin). A dispersed molybdenum catalyst was evaluated for its performance. The effect of the dispersed catalyst on eliminating solids buildup was also evaluated. Half volume reactors were used with supported Criterion 324 1/16`` catalyst in the second stage at a catalyst replacement rate of 3 lb/ton of MFmore » coal. The hybrid dispersed plus supported catalyst system was tested for the effect of space velocity, second stage temperature, and molybdenum concentration. The supported catalyst was removed from the second stage for one test period to see the performance of slurry reactors. Iron oxide was used as slurry catalyst at a rate of 2 wt % MF coal throughout the run (dimethyl disulfide (DMDS) was used as the sulfiding agent). The close-coupled reactor unit was on-stream for 1271.2 hours for an on-stream factor of 89.8% and the ROSE-SR unit was on-feed for 1101.6 hours for an on-stream factor of 90.3% for the entire run.« less

Anaerobic/aerobic treatment of a petrochemical wastewater from two aromatic transformation processes by fluidized bed reactors.

PubMed

Estrada-Arriaga, Edson B; Ramirez-Camperos, Esperanza; Moeller-Chavez, Gabriela E; García-Sanchez, Liliana

2012-01-01

An integrated fluidized bed reactor (FBR) has been employed as the treatment for petrochemical industry wastewaters with high organic matter and aromatic compounds, under anaerobic and aerobic conditions. The system was operated at hydraulic residence time (HRT) of 2.7 and 2.2 h in the anaerobic and aerobic reactor, respectively. The degree of fluidization in the beds was 30%. This system showed a high performance on the removal of organic matter and aromatic compounds. At different organic loading rates (OLR), the chemical oxygen demand (COD) removal in the anaerobic reactor was close to 85% and removals of the COD up to 94% were obtained in the aerobic reactor. High removals of benzene, toluene, ethylbenzene, xylenes, styrene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene and naphthalene were achieved in this study.

Advanced development of immobilized enzyme reactors

NASA Technical Reports Server (NTRS)

Jolly, Clifford D.; Schussel, Leonard J.; Carter, Layne

1991-01-01

Fixed-bed reactors have been used at NASA-Marshall to purify wastewater generated by an end-use equipment facility, on the basis of a combination of multifiltration unibeds and enzyme unibeds. The enzyme beds were found to effectively remove such targeted organics as urea, alcohols, and aldehydes, down to levels lying below detection limits. The enzyme beds were also found to remove organic contaminants not specifically targeted.

Catalytic decomposition of methanol for onboard hydrogen generation

NASA Technical Reports Server (NTRS)

Brabbs, T.

1978-01-01

The steam reformation of an equimolar mixture of methanol and water on a copper chromite catalyst was studied at three furnace temperatures and at feed space velocities from 800 to 2600 per hour. The hydrogen space velocity could be related to the reactor temperature by the equation Sv = A exp (-omega T), where A and omega are constants determined for each value of alpha and T is temperature. At a methanol conversion of 0.87 and a reactor temperature of 589 K, the extrapolated value of the hydrogen space velocity was 9400 per hour. This velocity was used to estimate the size of an onboard hydrogen reactor for automotive applications. Such a reactor would need only about 0.8 liter of catalyst to produce 7630 STP liters (1.5 lb) of hydrogen per hour. This quantity of catalyst would fit into nine tubes 17.8 centimeters along and 2.54 centimeters in inside diameter, which is smaller than most mufflers. The reactor products would contain 12 to 13 percent more chemical energy than the incoming methanol and water.

Effect of biogenic fermentation impurities on lactic acid hydrogenation to propylene glycol.

PubMed

Zhang, Zhigang; Jackson, James E; Miller, Dennis J

2008-09-01

The effect of residual impurities from glucose fermentation to lactic acid (LA) on subsequent ruthenium-catalyzed hydrogenation of LA to propylene glycol (PG) is examined. Whereas refined LA feed exhibits stable conversion to PG over carbon-supported ruthenium catalyst in a trickle bed reactor, partially refined LA from fermentation shows a steep decline in PG production over short (<40 h) reaction times followed by a further slow decay in performance. Addition of model impurities to refined LA has varying effects: organic acids, sugars, or inorganic salts have little effect on conversion; alanine, a model amino acid, results in a strong but reversible decline in conversion via competitive adsorption between alanine and LA on the Ru surface. The sulfur-containing amino acids cysteine and methionine irreversibly poison the catalyst for LA conversion. Addition of 0.1 wt% albumin as a model protein leads to slow decline in rate, consistent with pore plugging or combined pore plugging and poisoning of the Ru surface. This study points to the need for integrated design and operation of biological processes and chemical processes in the biorefinery in order to make efficient conversion schemes viable.

Isomerization of C.sub.4 alkenes

DOEpatents

Smith, Jr., Lawrence A.

1984-01-01

A method for isomerizing isobutene or n-butene to produce a mixture of isobutene and normal butene, and polymerizing at least a portion thereof to produce isobutene/n-butene codimer, which comprieses feeding at least 80 weight % of either the isobutene or n-butene to a catalytic distillation reactor containing a fixed bed acidic cation exchange resin catalyst packing which provides both the catalyst sites and distillation sites for the reaction products, isomerizing a portion of the isobutene or n-butene to produce a mixture of isobutene and n-butene and reacting at least a portion of the isobutene and n-butene to form codimer of isobutene and n-butene, whereby an overhead fraction containing any unreacted isobutene and n-butene and a bottoms fraction containing codimer is produced. The result of the reaction is substantially the same regardless whether the feed is isobutene or n-butene. Other aspects of the invention, include combinations of procedures to produce high purity isobutene and n-butene. Either isobutene or n-butene product (depending on the desired product) can be recycled as feed, thus substantially carrying out the isomerization to extinction and total conversion to the desired product.

Hydrogen production through aqueous-phase reforming of ethylene glycol in a washcoated microchannel.

PubMed

D'Angelo, M Fernanda Neira; Ordomsky, Vitaly; Paunovic, Violeta; van der Schaaf, John; Schouten, Jaap C; Nijhuis, T Alexander

2013-09-01

Aqueous-phase reforming (APR) of biocarbohydrates is conducted in a catalytically stable washcoated microreactor where multiphase hydrogen removal enhances hydrogen efficiency. Single microchannel experiments are conducted following a simplified model based on the microreactor concept. A coating method to deposit a Pt-based catalyst on the microchannel walls is selected and optimized. APR reactivity tests are performed by using ethylene glycol as the model compound. Optimum results are achieved with a static washcoating technique; a highly uniform and well adhered 5 μm layer is deposited on the walls of a 320 μm internal diameter (ID) microchannel in one single step. During APR of ethylene glycol, the catalyst layer exhibits high stability over 10 days after limited initial deactivation. The microchannel presents higher conversion and selectivity to hydrogen than a fixed-bed reactor. The benefits of using a microreactor for APR can be further enhanced by utilizing increased Pt loadings, higher reaction temperatures, and larger carbohydrates (e.g., glucose). The use of microtechnology for aqueous-phase reforming will allow for a great reduction in the reformer size, thus rendering it promising for distributed hydrogen production. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Production of bio-hydrogenated diesel by catalytic hydrotreating of palm oil over NiMoS2/γ-Al2O3 catalyst.

PubMed

Srifa, Atthapon; Faungnawakij, Kajornsak; Itthibenchapong, Vorranutch; Viriya-Empikul, Nawin; Charinpanitkul, Tawatchai; Assabumrungrat, Suttichai

2014-04-01

Catalytic hydrotreating of palm oil (refined palm olein type) to produce bio-hydrogenated diesel (BHD) was carried out in a continuous-flow fixed-bed reactor over NiMoS2/γ-Al2O3 catalyst. Effects of dominant hydrotreating parameters: temperature: 270-420°C; H2 pressure: 15-80 bar; LHSV: 0.25-5.0 h(-1); and H2/oil ratio: 250-2000 N(cm(3)/cm(3)) on the conversion, product yield, and a contribution of hydrodeoxygenation (HDO) and decarbonylation/decarboxylation (DCO/DCO2) were investigated to find the optimal hydrotreating conditions. All calculations including product yield and the contribution of HDO and DCO/DCO2 were extremely estimated based on mole balance corresponding to the fatty acid composition in feed to fully understand deoxygenation behaviors at different conditions. These analyses demonstrated that HDO, DCO, and DCO2 reactions competitively occurred at each condition, and had different optimal and limiting conditions. The differences in the hydrotreating reactions, liquid product compositions, and gas product composition were also discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Catalytic cracking of non-edible sunflower oil over ZSM-5 for hydrocarbon bio-jet fuel.

PubMed

Zhao, Xianhui; Wei, Lin; Julson, James; Qiao, Qiquan; Dubey, Ashish; Anderson, Gary

2015-03-25

Non-edible sunflower oils that were extracted from sunflower residual wastes were catalytically cracked over a ZSM-5 catalyst in a fixed-bed reactor at three different reaction temperatures: 450°C, 500°C and 550°C. The catalyst was characterized using XRD, FT-IR, BET and SEM. Characterizations of the upgraded sunflower oils, hydrocarbon fuels, distillation residues and non-condensable gases were carried out. The effect of the reaction temperature on the yield and quality of liquid products was discussed. The results showed that the reaction temperature affected the hydrocarbon fuel yield but had a minor influence on its properties. The highest conversion efficiency from sunflower oils to hydrocarbon fuels was 30.1%, which was obtained at 550°C. The reaction temperature affected the component content of the non-condensable gases. The non-condensable gases generated at 550°C contained the highest content of light hydrocarbons (C1-C5), CO, CO2 and H2. Compared to raw sunflower oils, the properties of hydrocarbon fuels including the dynamic viscosity, pH, moisture content, density, oxygen content and heating value were improved. Copyright © 2015 Elsevier B.V. All rights reserved.

Isomerization of C[sub 4] alkenes

DOEpatents

Smith, L.A. Jr.

1984-11-13

A method is described for isomerizing isobutene or n-butene to produce a mixture of isobutene and normal butene, and polymerizing at least a portion thereof to produce isobutene/n-butene co-dimer, which comprises feeding at least 80 weight % of either the isobutene or n-butene to a catalytic distillation reactor containing a fixed bed acidic cation exchange resin catalyst packing which provides both the catalyst sites and distillation sites for the reaction products, isomerizing a portion of the isobutene or n-butene to produce a mixture of isobutene and n-butene and reacting at least a portion of the isobutene and n-butene to form co-dimer of isobutene and n-butene, whereby an overhead fraction containing any unreacted isobutene and n-butene and a bottoms fraction containing co-dimer is produced. The result of the reaction is substantially the same regardless whether the feed is isobutene or n-butene. Other aspects of the invention, include combinations of procedures to produce high purity isobutene and n-butene. Either isobutene or n-butene product (depending on the desired product) can be recycled as feed, thus substantially carrying out the isomerization to extinction and total conversion to the desired product. 1 fig.

Technology development for iron Fischer-Tropsch catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

O`Brien, R.J.; Raje, A.; Keogh, R.A.

1995-12-31

The objective of this research project is to develop the technology for the production of physically robust iron-based Fischer-Tropsch catalysts that have suitable activity, selectivity and stability to be used in the slurry phase synthesis reactor development. The catalysts that are developed shall be suitable for testing in the Advanced Fuels Development Facility at LaPorte, Texas, to produce either low-or high-alpha product distributions. Previous work by the offeror has produced a catalyst formulation that is 1.5 times as active as the {open_quotes}standard-catalyst{close_quotes} developed by German workers for slurry phase synthesis. In parallel, work will be conducted to design a high-alphamore » iron catalyst this is suitable for slurry phase synthesis. Studies will be conducted to define the chemical phases present at various stages of the pretreatment and synthesis stages and to define the course of these changes. The oxidation/reduction cycles that are anticipated to occur in large, commercial reactors will be studied at the laboratory scale. Catalyst performance will be determined for catalysts synthesized in this program for activity, selectivity and aging characteristics.« less

Novel methods of stabilization of Raney-Nickel catalyst for fuel-cell electrodes

NASA Astrophysics Data System (ADS)

Al-Saleh, M. A.; Sleem-Ur-Rahman; Kareemuddin, S. M. M. J.; Al-Zakri, A. S.

Two new methods of stabilizing Raney-Nickel (Raney-Ni) catalyst for making fuel-cell anodes were studied. In the first method, the catalyst was oxidized with aqueous H 2O 2 solution, while in the second, oxygen/air (O 2/air) was used in a slurry reactor. Effects of different concentrations of H 2O 2 (5-25 wt.%) and different pressures (10-20 psig) of gas were investigated. The stabilized catalyst was characterized using BET surface area, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The catalyst was used in fuel-cell anodes and the electrochemical performance was determined in an alkaline half-cell. The results were compared with electrodes prepared using conventionally stabilized catalysts. The hydrogen peroxide-treated catalyst has higher BET surface area and produces electrodes with lower polarization. In addition to this, H 2O 2 treatment is convenient, fast and needs simple equipment which involves no instrumentation. Use of oxygen in a slurry reactor to stabilize the catalyst is also convenient but electrode performance is relatively poor.

Catalyst Bed Instability Within the USFE H2O2/JP-8 Rocket Engine

NASA Technical Reports Server (NTRS)

Johnson, Curtis W.; Anderson, William; Ross, Robert; Lyles, G. (Technical Monitor)

2000-01-01

Orbital Sciences Corporation has been awarded a contract by NASA's Marshall Space Flight Center, in cooperation with the U.S. Air Force Research Laboratory's Military Space Plane Technology Program Office, for the Upper Stage Flight Experiment (USFE) program. Orbital is designing, developing, and will flight test a new low-cost, 10,000 lbf hydrogen peroxide/ JP-8 pressure fed liquid rocket. During combustion chamber tests at NASA Stennis Space Center (SSC) of the USFE engine, the catalyst bed showed a low frequency instability occurring as the H202 flow reached about 1/3 its design rate. This paper reviews the USFE catalyst bed and combustion chamber and its operation, then discusses the dynamics of the instability. Next the paper describes the dynamic computer model used to recreate the instability. The model was correlated to the SSC test data, and used to investigate possible solutions to the problem. The combustion chamber configuration which solved the instability is shown, and the subsequent stable operation presented.

The effects of aniline impurities on monopropellant hydrazine thruster performance

NASA Technical Reports Server (NTRS)

Holcomb, L.; Mattson, L.; Oshiro, R.

1976-01-01

Both a 0.45-N and a 0.9-N thruster representative of the designs being flown on 3-axis stabilized spacecraft were used in testing various grades of hydrazine for the phenomenon of monopropellant hydrazine thruster catalyst bed poisoning. Both designs employed Shell 405 ABSG spontaneous catalyst. It is found that pulse shape distortion can be minimized, if not eliminated, by using aniline-free hydrazine. The mechanisms for both steady-state and pulse-mode performance loss are associated with the formation of a catalyst coke similar to the polycyclic aromatic poisons encountered in the petroleum industry. These poisoning mechanisms are reversible, with high-temperature operation being required to drive off the aniline coke deposits. It is recommended that a purified-grade hydrazine be considered for any mission that imposes operational conditions on a thruster which can result in aniline-induced poisoning of the catalyst bed.

Application of an adsorptive-thermocatalytic process for BTX removal from polluted air flow

PubMed Central

2014-01-01

Background Zero valent iron and copper oxide nanoparticles (30-60 nm) were coated on a bed of natural zeolite (Clinoptilolite) with 1-2 mm grains and arranged as a dual filter in a stainless steel cylindrical reactor (I.D 4.5 cm and L = 30 cm) to investigating the coated bed removal efficiency for BTX. The experiments were conducted in three steps. First, with an air flow of 1.5 L/min and temperature range of 38 (ambient temperature) to 600°C the BTX removal and mineralization was surveyed. Then, in an optimized temperature the effect of flow rate and pollution loading rate were surveyed on BTX removal. Results The BTX removal at 300 and 400°C were respectively up to 87.47% and 94.03%. Also in these temperatures respectively 37.21% and 90.42% of BTX mineralization were achieved. In the retention times of 14.1 s and 7.05 s, respectively 96.18% and 78.42% of BTX was removed. Conclusions According to the results, this adsorptive-thermocatalytic process with using Clinoptilolite as an adsorbent bed and combined Fe0 and Cu2O nanoparticles as catalysts can be an efficient and competitive process in the condition of high flow rate and high pollution loading rate with an adequate process temperature of 350°C. PMID:24955244

Treatment of semivolatile compounds in high strength wastes using an anaerobic expanded-bed GAC reactor

EPA Science Inventory

The potential of the anaerobic, expanded bed granular activated carbon (GAC) reactor in treating a high strength waste containing RCRA semivolatile organic compounds (VOCs) was studied. Six semivolatiles, orthochlorophenol, nitrobenzene, naphthalene, para-nitrophenol, lindane, a...

Microwave-assisted direct synthesis of butene from high-selectivity methane

NASA Astrophysics Data System (ADS)

Lu, Yi-heng; Li, Kang; Lu, Yu-wei

2017-12-01

Methane was directly converted to butene liquid fuel by microwave-induced non-oxidative catalytic dehydrogenation under 0.1-0.2 MPa. The results show that, under microwave heating in a two-stage fixed-bed reactor, in which nickel powder and NiOx-MoOy/SiO2 are used as the catalyst, the methane-hydrogen mixture is used as the raw material, with no acetylene detected. The methane conversion is more than 73.2%, and the selectivity of methane to butene is 99.0%. Increasing the hydrogen/methane feed volume ratio increases methane conversion and selectivity. Gas chromatography/electron impact ionization/mass spectrometry chromatographic analysis showed that the liquid fuel produced by methane dehydrogenation oligomerization contained 89.44% of butene, and the rest was acetic acid, ethanol, butenol and butyric acid, and the content was 1.0-3.0 wt%.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rotman, D.

After nearly a decade of work and $150 million in development costs. Exxon Research and Engineering (ER&E; Florham Park, NJ) says its natural gas conversion process based on Fischer-Tropsch technology is ready for full-scale commercialization. ER&E is looking to entice one of Exxon`s other business units into building a plant based on the process. The Exxon technology makes refinery or petrochemical feedstocks from natural gas in an integrated three-step process, including fluid-bed reactor to make synthesis gas and a hydrocarbon synthesis step using a proprietary Fischer-Tropsch catalyst. Exxon has successfully demonstrated the process at a pilot plant in Baton Rouge,more » LA but says no commercialization decision has been made. ER&E estimates that to commercialize the technology economically will require a large gas conversion plant-with a price tag of about $2 billion.« less

Two-stage dehydration of sugars

DOEpatents

Holladay, Johnathan E [Kennewick, WA; Hu, Jianli [Kennewick, WA; Wang, Yong [Richland, WA; Werpy, Todd A [West Richland, WA

2009-11-10

The invention includes methods for producing dianhydrosugar alcohol by providing an acid catalyst within a reactor and passing a starting material through the reactor at a first temperature. At least a portion of the staring material is converted to a monoanhydrosugar isomer during the passing through the column. The monoanhydrosugar is subjected to a second temperature which is greater than the first to produce a dianhydrosugar. The invention includes a method of producing isosorbide. An initial feed stream containing sorbitol is fed into a continuous reactor containing an acid catalyst at a temperature of less than 120.degree. C. The residence time for the reactor is less than or equal to about 30 minutes. Sorbitol converted to 1,4-sorbitan in the continuous reactor is subsequently provided to a second reactor and is dehydrated at a temperature of at least 120.degree. C. to produce isosorbide.

Investigation of Anaerobic Fluidized Bed Reactor/ Aerobic Moving Bed Bio Reactor (AFBR/MMBR) System for Treatment of Currant Wastewater

PubMed Central

JAFARI, Jalil; MESDAGHINIA, Alireza; NABIZADEH, Ramin; FARROKHI, Mehrdad; MAHVI, Amir Hossein

2013-01-01

Background: Anaerobic treatment methods are more suitable for the treatment of concentrated wastewater streams, offer lower operating costs, the production of usable biogas product. The aim of this study was to investigate the performance of an Anaerobic Fluidized Bed Reactor (AFBR)-Aerobic Moving Bed Bio Reactor (MBBR) in series arrangement to treat Currant wastewater. Methods: The bed materials of AFBR were cylindrical particles made of PVC with a diameter of 2–2.3 mm, particle density of 1250 kg/m3. The volume of all bed materials was 1.7 liter which expanded to 2.46 liters in fluidized situation. In MBBR, support media was composed of 1.5 liters Bee-Cell 2000 having porosity of 87% and specific surface area of 650m2/m3. Results: When system operated at 35 ºC, chemical oxygen demand (COD) removal efficiencies were achieved to 98% and 81.6% for organic loading rates (OLR) of 9.4 and 24.2 g COD/l.d, and hydraulic retention times (HRT) of 48 and 18 h, in average COD concentration feeding of 18.4 g/l, respectively. Conclusion: The contribution of AFBR in total COD removal efficiency at an organic loading rate (OLR) of 9.4 g COD/l.d was 95%, and gradually decreased to 76.5% in OLR of 24.2 g COD/l.d. Also with increasing in organic loading rate the contribution of aerobic reactor in removing COD gradually decreased. In this system, the anaerobic reactor played the most important role in the removal of COD, and the aerobic MBBR was actually needed to polish the anaerobic treated wastewater. PMID:26056640

Circulating moving bed system for CO.sub.2 separation, and method of same

DOEpatents

Elliott, Jeannine Elizabeth; Copeland, Robert James

2016-12-27

A circulating moving bed and process for separating a carbon dioxide from a gas stream is disclosed. The circulating moving bed can include an adsorption reactor and a desorption reactor, and a sorbent that moves through the two reactors. The sorbent can enter the adsorptive reactor and one end and move to an exit point distal to its entry point, while a CO.sub.2 feed stream can enter near the distal point and move countercurrently through the sorbent to exit at a position near the entry point of the sorbent. The sorbent can adsorb the CO.sub.2 by concentration swing adsorption and adsorptive displacement. The sorbent can then transfer to a regeneration reactor and can move countercurrently against a flow of steam through the regeneration reactor. The sorbent can be regenerated and the carbon dioxide recaptured by desorbing the carbon dioxide from the sorbent using concentration swing desorption and desorptive displacement with steam.

Development of Mesoporous Nanocatalysts for Production of Hydrogen and Fisher Tropsch Studies

NASA Astrophysics Data System (ADS)

Abrokwah, Richard Yeboah

The primary aim of this study was to develop mesoporous nanocatalysts for (i) hydrogen production via steam reforming of methanol (SRM) in a tubular reactor, and (ii) syngas conversion to hydrocarbons via Fisher-Tropsch synthesis using silicon microchannel microreactors. The mesoporous catalysts for SRM were prepared by an optimized one-pot hydrothermal synthesis procedure. The catalysts were investigated for SRM activity in a packed bed tubular reactor using metals, namely, Cu, Co, Ni, Pd, Zn, and Sn. The metals were incorporated in different supports -MCM-41, SBA-15, CeO2, TiO2, and ZrO2 to investigate the influence of support on catalyst properties. A sharp contrast in catalyst performance was noticed depending on the type of support employed. For example, in SRM at 250 °C, Cu supported on amorphous silica SBA-15 and MCM-41 produced significantly less CO (< 7%) compared to other crystalline supports Cu-TiO2 and Cu/ZrO2 that showed high CO selectivity of ˜56% and ˜37%, respectively. Amongst all the metals studied for SRM activity using 1:3 methanol:water mole ratio at 250 °C, 10%Cu-MCM-41 showed the best performance with 68% methanol conversion, 100% H2 , ˜6 % CO, 94% CO2 selectivities, and no methane formation. Furthermore, 10%Cu-CeO2 yielded the lowest CO selectivity of 1.84% and the highest CO2 selectivity of ˜98% at 250 °C. Stability studies of the catalysts conducted for time-on-stream of 40 h at 300 °C revealed that Cu-MCM41 was the most stable and displayed consistent steady state conversion of ˜74%. Our results indicate that, although coking played an influential role in deactivation of most catalysts, thermal sintering and changes in MCM-41 structure can be responsible for the catalyst deactivation. For monomtetallic systems, the MCM-41 supported catalysts especially Pd and Sn showed appreciable hydrothermal stability under the synthesis and reaction conditions. While bimetallic Pd-Co-MCM-41 and Cu-Ni-MCM-41 catalysts produced more CO, Cu-Zn-MCM-41 and Cu-Sn-MCM-41exhibited better SRM activity, and produced much less CO and CH4. In spite of the improved the stability and dispersion of the monometallic active sites in the support, no noticeable synergistic activity was observed in terms of H2 and CO selectivities in the multimetallic catalysts. For the Fisher-Tropsch (F-T) studies, Co-TiO 2, Fe-TiO2 and Ru-TiO2 catalysts were prepared by the sol-gel method and coated on 116 microchannels (50mum wide x 100mum deep) of a Si-microreactor. The F-T process parameters such as temperature, pressure and flow rates were controlled by an in-house setup programmed by LabVIEWRTM. The effect of temperature on F-T activity in the range of 150 to 300°C was investigated at 1 atm, a flow rate of 6 ml/min and a constant H2:CO molar ratio of 2:1. In our initial studies at 220 °C, 12%Ru-TiO2 showed higher CO conversion of 74% and produced the highest C2-C4 hydrocarbon selectivity-of ˜11% ethane, 22% propane and ˜17% butane. The overall catalyst stability and performance was in the order of 12%Ru-TiO2>> 12%Fe-TiO2 > 12%Co-TiO2.

Fuel processor for fuel cell power system

DOEpatents

Vanderborgh, Nicholas E.; Springer, Thomas E.; Huff, James R.

1987-01-01

A catalytic organic fuel processing apparatus, which can be used in a fuel cell power system, contains within a housing a catalyst chamber, a variable speed fan, and a combustion chamber. Vaporized organic fuel is circulated by the fan past the combustion chamber with which it is in indirect heat exchange relationship. The heated vaporized organic fuel enters a catalyst bed where it is converted into a desired product such as hydrogen needed to power the fuel cell. During periods of high demand, air is injected upstream of the combustion chamber and organic fuel injection means to burn with some of the organic fuel on the outside of the combustion chamber, and thus be in direct heat exchange relation with the organic fuel going into the catalyst bed.

The catalytic activity of CoMo/USY on deoxygenation reaction of anisole in a batch reactor

NASA Astrophysics Data System (ADS)

Nugrahaningtyas, K. D.; Putri, I. F.; Heraldy, E.; Hidayat, Y.

2018-04-01

The catalytic hydrodeoxigenation of the bio oil model compounds (biomass pyrolysis results) typically uses sulphide catalysts. In this study, we studied the activity of non-sulphide catalyst, the effect of temperature and reaction time on anisole deoxygenation. The catalytic activity was performed in a batch reactor, using N2 gas at 1 bar of pressure. The product was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The result showed that the Co-Mo/USY catalyst perform a highest activity and produce pentamethylbenzene, an oxygen free products, when reaction time is 2 hours. The Co-Mo/USY catalysts has the value of the total yield of the product increased with time increase drastically.

Full scale fluidized bed anaerobic reactor for domestic wastewater treatment: performance, sludge production and biofilm.

PubMed

Mendonça, N M; Niciura, C L; Gianotti, E P; Campos, J R

2004-01-01

This paper describes the performance, sludge production and biofilm characteristics of a full scale fluidized bed anaerobic reactor (32 m3) for domestic wastewater treatment. The reactor was operated with 10.5 m x h(-1) upflow velocity, 3.2 h hydraulic retention time, and recirculation ratio of 0.85 and it presented removal efficiencies of 71+/-8% of COD and 77+/-14% of TSS. During the apparent steady-state period, specific sludge production and sludge age in the reactor were (0.116+/-0.033) kgVSS. kgCOD(-1) and (12+/-5)d, respectively. Biofilm formed in the reactor presented two different patterns: one of them at the beginning of the colonization and the other of mature biofilm. These different colonization patterns are due to bed stratification in the reactor, caused by the difference in local-energy dissipation rates along the reactor's height, and density, shape, etc. of the bioparticles. The biofilm population is formed mainly of syntrophic consortia among sulfate reducing bacteria, methanogenic archaea such as Methanobacterium and Methanosaeta-like cells.

TREATMENT OF VOCS IN HIGH STRENGTH WASTES USING AN ANAEROBIC EXPANDED-BED GAS REACTOR

EPA Science Inventory

The potential of the expanded-bed granular activated carbon (GAC) anaerobic reactor in treating a high strength waste containing RCRA volatile organic compounds (VOCs) was studied. A total of six VOCs, methylene chloride, chlorobenzene, carbon tetrachloride, chloroform, toluene ...

ANAEROBIC/AEROBIC BIODEGRADATION OF PENTACHLOROPHENOL USING GAC FLUIDIXED BED REACTORS: OPTIMIZATION OF THE EMPTY BED CONTACT TIME

EPA Science Inventory

An integrated reactor system has been developed to remediate pentachlorophenol (PCP) containing wastes using sequential anaerobic and aerobic biodegradation. Anaerobically, PCP was degraded to approximately equimolar concentrations (>99%) of chlorophenol (CP) in a granular activa...

Anh To | NREL

Science.gov Websites

pyrolysis vapors Catalytic depolymerization of biomass Process scale-up for catalyst synthesis and testing continuous flow reactors (gas & liquid phases) Catalyst synthesis: zeolites, supported metals, and

Design and fabrication of a fixed-bed batch type pyrolysis reactor for pilot scale pyrolytic oil production in Bangladesh

NASA Astrophysics Data System (ADS)

Aziz, Mohammad Abdul; Al-khulaidi, Rami Ali; Rashid, MM; Islam, M. R.; Rashid, MAN

2017-03-01

In this research, a development and performance test of a fixed-bed batch type pyrolysis reactor for pilot scale pyrolysis oil production was successfully completed. The characteristics of the pyrolysis oil were compared to other experimental results. A solid horizontal condenser, a burner for furnace heating and a reactor shield were designed. Due to the pilot scale pyrolytic oil production encountered numerous problems during the plant’s operation. This fixed-bed batch type pyrolysis reactor method will demonstrate the energy saving concept of solid waste tire by creating energy stability. From this experiment, product yields (wt. %) for liquid or pyrolytic oil were 49%, char 38.3 % and pyrolytic gas 12.7% with an operation running time of 185 minutes.

Development of a reactor with carbon catalysts for modular-scale, low-cost electrochemical generation of H 2O 2

DOE PAGES

Chen, Zhihua; Chen, Shucheng; Siahrostami, Samira; ...

2017-03-01

The development of small-scale, decentralized reactors for H 2O 2 production that can couple to renewable energy sources would be of great benefit, particularly for water purification in the developing world. Herein, we describe our efforts to develop electrochemical reactors for H 2O 2 generation with high Faradaic efficiencies of >90%, requiring cell voltages of only ~1.6 V. The reactor employs a carbon-based catalyst that demonstrates excellent performance for H 2O 2 production under alkaline conditions, as demonstrated by fundamental studies involving rotating-ring disk electrode methods. Finally, the low-cost, membrane-free reactor design represents a step towards a continuous, modular-scale, de-centralizedmore » production of H 2O 2.« less

Evaluation of Selected Chemical Processes for Production of Low-cost Silicon, Phase 3. [using a fluidized bed reactor

NASA Technical Reports Server (NTRS)

Blocher, J. M., Jr.; Browning, M. F.

1979-01-01

The construction and operation of an experimental process system development unit (EPSDU) for the production of granular semiconductor grade silicon by the zinc vapor reduction of silicon tetrachloride in a fluidized bed of seed particles is presented. The construction of the process development unit (PDU) is reported. The PDU consists of four critical units of the EPSDU: the fluidized bed reactor, the reactor by product condenser, the zinc vaporizer, and the electrolytic cell. An experimental wetted wall condenser and its operation are described. Procedures are established for safe handling of SiCl4 leaks and spills from the EPSDU and PDU.

Synthesis biolubricant from rubber seed oil

NASA Astrophysics Data System (ADS)

Hung, Nguyen Tran Dong; Tuyen, Dang Thi Hong; Viet, Tran Tan

2017-09-01

The objective was biolubricant preparation from rubber seed oil (RSO) using polymerization reactor with/without catalyst in batch reactor. Before become reactant in polymerization reaction, a non-edible rubber seed oil was converted into methyl ester by esterification/tranesterification reaction with methanol and acid/base catalyst. The polymerization reaction parameters investigated were reaction time, temperature and weight ratio (catalyst with feed), and their effect on the bio lubricant formation. The result show significant conversion of methyl ester to bio lubricant in the temperature reaction of 160°C, reaction time of 2h min and ratio of super acid catalyst (tetrafluoroboric acid-sHBF4) of 3 %w/w. The resulting products were confirmed by GC-MS, FTIR spectroscopy and also analyzed for the viscosity. The best viscosity value of RSOFAME polymer was 110.6 cSt when the condition polymerization reaction were 160 °C, reaction time 3h, 6 wt% mass ratio of oil:catalyst.

Spatially and temporally resolved gas distributions around heterogeneous catalysts using infrared planar laser-induced fluorescence

PubMed Central

Zetterberg, Johan; Blomberg, Sara; Gustafson, Johan; Evertsson, Jonas; Zhou, Jianfeng; Adams, Emma C.; Carlsson, Per-Anders; Aldén, Marcus; Lundgren, Edvin

2015-01-01

Visualizing and measuring the gas distribution in close proximity to a working catalyst is crucial for understanding how the catalytic activity depends on the structure of the catalyst. However, existing methods are not able to fully determine the gas distribution during a catalytic process. Here we report on how the distribution of a gas during a catalytic reaction can be imaged in situ with high spatial (400 μm) and temporal (15 μs) resolution using infrared planar laser-induced fluorescence. The technique is demonstrated by monitoring, in real-time, the distribution of carbon dioxide during catalytic oxidation of carbon monoxide above powder catalysts. Furthermore, we demonstrate the versatility and potential of the technique in catalysis research by providing a proof-of-principle demonstration of how the activity of several catalysts can be measured simultaneously, either in the same reactor chamber, or in parallel, in different reactor tubes. PMID:25953006

Preliminary results from screening tests of commercial catalysts with potential use in gas turbine combustors. Part 1: Furnace studies of catalyst activity

NASA Technical Reports Server (NTRS)

Anderson, D. N.

1976-01-01

Thirty commercially produced monolith and pellet catalysts were tested as part of a screening process to select catalysts suitable for use in a gas turbine combustor. The catalysts were contained in a 1.8 centimeter diameter quartz tube and heated to temperatures varying between 300 and 1,200 K while a mixture of propane and air passed through the bed at space velocities of 44,000 to 70,000/hour. The amount of propane oxidized was measured as a function of catalyst temperature. Of the samples tested, the most effective catalysts proved to be noble metal catalysts on monolith substrates.

The effect of catalyst length and downstream reactor distance on catalytic combustor performance

NASA Technical Reports Server (NTRS)

Anderson, D.

1980-01-01

A study was made to determine the effects on catalytic combustor performance which resulted from independently varying the length of a catalytic reactor and the length available for gas-phase reactions downstream of the catalyst. Monolithic combustion catalysts from three manufacturers were tested in a combustion test rig with no. 2 diesel fuel. Catalytic reactor lengths of 2.5 and 5.4 cm, and downstream gas-phase reaction distances of 7.3, 12.4, 17.5, and 22.5 cm were evaluated. Measurements of carbon monoxide, unburned hydrocarbons, nitrogen oxides, and pressure drop were made. The catalytic-reactor pressure drop was less than 1 percent of the upstream total pressure for all test configurations and test conditions. Nitrogen oxides and unburned hydrocarbons emissions were less than 0.25 g NO2/kg fuel and 0.6 g HC/kg fuel, respectively. The minimum operating temperature (defined as the adiabatic combustion temperature required to obtain carbon monoxide emissions below a reference level of 13.6 g CO/kg fuel) ranged from 1230 K to 1500 K for the various conditions and configurations tested. The minimum operating temperature decreased with increasing total (catalytic-reactor-plus-downstream-gas-phase-reactor-zone) residence time but was independent of the relative times spent in each region when the catalytic-reactor residence time was greater than or equal to 1.4 ms.

Method and apparatus for chemically altering fluids in continuous flow

DOEpatents

Heath, W.O.; Virden, J.W. Jr.; Richardson, R.L.; Bergsman, T.M.

1993-10-19

The present invention relates to a continuous flow fluid reactor for chemically altering fluids. The reactor operates on standard frequency (50 to 60 Hz) electricity. The fluid reactor contains particles that are energized by the electricity to form a corona throughout the volume of the reactor and subsequently a non-equilibrium plasma that interacts with the fluid. Particles may form a fixed bed or a fluid bed. Electricity may be provided through electrodes or through an inductive coil. Fluids include gases containing exhaust products and organic fuels requiring oxidation. 4 figures.

Method and apparatus for chemically altering fluids in continuous flow

DOEpatents

Heath, William O.; Virden, Jr., Judson W.; Richardson, R. L.; Bergsman, Theresa M.

1993-01-01

The present invention relates to a continuous flow fluid reactor for chemically altering fluids. The reactor operates on standard frequency (50 to 60 Hz) electricity. The fluid reactor contains particles that are energized by the electricity to form a corona throughout the volume of the reactor and subsequently a non-equilibrium plasma that interacts with the fluid. Particles may form a fixed bed or a fluid bed. Electricity may be provided through electrodes or through an inductive coil. Fluids include gases containing exhaust products and organic fuels requiring oxidation.

Methane production by attached film

DOEpatents

Jewell, William J.

1981-01-01

A method for purifying wastewater of biodegradable organics by converting the organics to methane and carbon dioxide gases is disclosed, characterized by the use of an anaerobic attached film expanded bed reactor for the reaction process. Dilute organic waste material is initially seeded with a heterogeneous anaerobic bacteria population including a methane-producing bacteria. The seeded organic waste material is introduced into the bottom of the expanded bed reactor which includes a particulate support media coated with a polysaccharide film. A low-velocity upward flow of the organic waste material is established through the bed during which the attached bacterial film reacts with the organic material to produce methane and carbon dioxide gases, purified water, and a small amount of residual effluent material. The residual effluent material is filtered by the film as it flows upwardly through the reactor bed. In a preferred embodiment, partially treated effluent material is recycled from the top of the bed to the bottom of the bed for further treatment. The methane and carbon dioxide gases are then separated from the residual effluent material and purified water.

Reactor for fluidized bed silane decomposition

NASA Technical Reports Server (NTRS)

Iya, Sridhar K. (Inventor)

1989-01-01

An improved heated fluidized bed reactor and method for the production of high purity polycrystalline silicon by silane pyrolysis wherein silicon seed particles are heated in an upper heating zone of the reactor and admixed with particles in a lower zone, in which zone a silane-containing gas stream, having passed through a lower cooled gas distribution zone not conducive to silane pyrolysis, contacts the heated seed particles whereon the silane is heterogeneously reduced to silicon.

Preliminary Safeguards Assessment for the Pebble-Bed Fluoride High-Temperature Reactor (PB-FHR) Concept

DOE Office of Scientific and Technical Information (OSTI.GOV)

Disser, Jay; Arthur, Edward; Lambert, Janine

2016-09-01

This report examines a preliminary design for a pebble bed fluoride salt-cooled high temperature reactor (PB-FHR) concept, assessing it from an international safeguards perspective. Safeguards features are defined, in a preliminary fashion, and suggestions are made for addressing further nuclear materials accountancy needs.

APPARATUS FOR SHORT TIME MEASUREMENTS IN A FIXED-BED, GAS/SOLID REACTOR

EPA Science Inventory

An apparatus for exposure of a solid to reactive process gas is described which makes possible short time (≥ 0.3 to 15 s) exposures in a fixed-bed reactor. Operating conditions for differential reaction with respect to the gas concentration and rapid quench for arresting hi...

ANALYSIS OF AN AEROBIC FLUIDIZED BED REACTOR DEGRADING MTBE AND BTEX AT REDUCED EBCTS

EPA Science Inventory

The purpose of this study was to investigate the biodegradation of MTBE and BTEX using a fluidized bed reactor (FBR) with granular activated carbon (GAC) as a biological attachment medium. Batch experiments were run to analyze the MTBE and TBA degradation kinetics of the culture ...

Fuel processing in integrated micro-structured heat-exchanger reactors

NASA Astrophysics Data System (ADS)

Kolb, G.; Schürer, J.; Tiemann, D.; Wichert, M.; Zapf, R.; Hessel, V.; Löwe, H.

Micro-structured fuel processors are under development at IMM for different fuels such as methanol, ethanol, propane/butane (LPG), gasoline and diesel. The target application are mobile, portable and small scale stationary auxiliary power units (APU) based upon fuel cell technology. The key feature of the systems is an integrated plate heat-exchanger technology which allows for the thermal integration of several functions in a single device. Steam reforming may be coupled with catalytic combustion in separate flow paths of a heat-exchanger. Reactors and complete fuel processors are tested up to the size range of 5 kW power output of a corresponding fuel cell. On top of reactor and system prototyping and testing, catalyst coatings are under development at IMM for numerous reactions such as steam reforming of LPG, ethanol and methanol, catalytic combustion of LPG and methanol, and for CO clean-up reactions, namely water-gas shift, methanation and the preferential oxidation of carbon monoxide. These catalysts are investigated in specially developed testing reactors. In selected cases 1000 h stability testing is performed on catalyst coatings at weight hourly space velocities, which are sufficiently high to meet the demands of future fuel processing reactors.

Hydroconversion of methyl laurate on bifunctional Ni2P/AlMCM-41 catalyst prepared via in situ phosphorization using triphenylphosphine

NASA Astrophysics Data System (ADS)

Zhao, Sha; Zhang, Zhena; Zhu, Kongying; Chen, Jixiang

2017-05-01

A series of Ni2P/AlMCM-41-x bifunctional catalysts with different Si/Al ratios (x) were synthesized by in situ phosphorization of Ni/AlMCM-41-x with triphenylphosphine (nominal Ni/P ratio of 0.75) at 300 °C on a fixed-bed reactor. For comparison, NiP/AlMCM-41-5-TPR was also prepared by the TPR method from the supported nickel phosphate with the Ni/P ratio of 1.0, during which metallic Ni rather than Ni2P formed. TEM images show that Ni and Ni2P particles uniformly distributed in Ni2P/AlMCM-41-x and NiP/AlMCM-41-5-TPR. The Ni2P/AlMCM-41-x acidity increased with decreasing the Si/Al ratio. In the hydroconversion of methyl laurate, the conversions were close to 100% on all catalysts at 360 °C, 3.0 MPa, methyl laurate WHSV of 2 h-1 and H2/methyl laurate ratio of 25. As to Ni2P/AlMCM-41-x, with decreasing the Si/Al ratio, the total selectivity to C11 and C12 hydrocarbons decreased, while the total selectivity to isoundecane and isododecane (Si-C11+i-C12) firstly increased and then decreased. Ni2P/AlMCM-41-5 gave the largest Si-C11+i-C12 of 43.2%. While NiP/AlMCM-41-5-TPR gave higher Si-C11+i-C12 than Ni2P/AlMCM-41-5, it was more active for the undesired Csbnd C bond cleavage and methanation. We propose that the in-situ phosphorization adopted here is a promising approach to preparing Ni2P-based bifunctional catalysts.