Analysis on Operating Parameter Design to Steam Methane Reforming in Heat Application RDE

NASA Astrophysics Data System (ADS)

Dibyo, Sukmanto; Sunaryo, Geni Rina; Bakhri, Syaiful; Zuhair; Irianto, Ign. Djoko

2018-02-01

The high temperature reactor has been developed with various power capacities and can produce electricity and heat application. One of heat application is used for hydrogen production. Most hydrogen production occurs by steam reforming that operated at high temperature. This study aims to analyze the feasibility of heat application design of RDE reactor in the steam methane reforming for hydrogen production using the ChemCAD software. The outlet temperature of cogeneration heat exchanger is analyzed to be applied as a feed of steam reformer. Furthermore, the additional heater and calculating amount of fuel usage are described. Results show that at a low mass flow rate of feed, its can produce a temperature up to 480°C. To achieve the temperature of steam methane reforming of 850°C the additional fired heater was required. By the fired heater, an amount of fuel usage is required depending on the Reformer feed temperature produced from the heat exchanger of the cogeneration system.

Catalytic glycerol steam reforming for hydrogen production

NASA Astrophysics Data System (ADS)

Dan, Monica; Mihet, Maria; Lazar, Mihaela D.

2015-12-01

Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H2. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al2O3. The catalyst was prepared by wet impregnation method and characterized through different methods: N2 adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H2, CH4, CO, CO2. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H2O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

Steam Methane Reformation Testing for Air-Independent Solid Oxide Fuel Cell Systems

NASA Technical Reports Server (NTRS)

Mwara, Kamwana N.

2015-01-01

Recently, NASA has been looking into utilizing landers that can be propelled by LOX-CH (sub 4), to be used for long duration missions. Using landers that utilize such propellants, also provides the opportunity to use solid oxide fuel cells as a power option, especially since they are able to process methane into a reactant through fuel reformation. One type of reformation, called steam methane reformation, is a process to reform methane into a hydrogen-rich product by reacting methane and steam (fuel cell exhaust) over a catalyst. A steam methane reformation system could potentially use the fuel cell's own exhaust to create a reactant stream that is hydrogen-rich, and requires less internal reforming of the incoming methane. Also, steam reformation may hold some advantages over other types of reforming, such as partial oxidation (PROX) reformation. Steam reformation does not require oxygen, while up to 25 percent can be lost in PROX reformation due to unusable CO (sub 2) reformation. NASA's Johnson Space Center has conducted various phases of steam methane reformation testing, as a viable solution for in-space reformation. This has included using two different types of catalysts, developing a custom reformer, and optimizing the test system to find the optimal performance parameters and operating conditions.

Catalytic glycerol steam reforming for hydrogen production

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

Dan, Monica, E-mail: monica.dan@itim-cj.ro; Mihet, Maria, E-mail: maria.mihet@itim-cj.ro; Lazar, Mihaela D., E-mail: diana.lazar@itim-cj.ro

2015-12-23

Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H{sub 2}. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al{sub 2}O{sub 3}. The catalyst was prepared by wet impregnation method and characterizedmore » through different methods: N{sub 2} adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H{sub 2}, CH{sub 4}, CO, CO{sub 2}. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H{sub 2}O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.« less

DATA QUALITY OBJECTIVES FOR SELECTING WASTE SAMPLES FOR THE BENCH STEAM REFORMER TEST

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

BANNING DL

2010-08-03

This document describes the data quality objectives to select archived samples located at the 222-S Laboratory for Fluid Bed Steam Reformer testing. The type, quantity and quality of the data required to select the samples for Fluid Bed Steam Reformer testing are discussed. In order to maximize the efficiency and minimize the time to treat Hanford tank waste in the Waste Treatment and Immobilization Plant, additional treatment processes may be required. One of the potential treatment processes is the fluid bed steam reformer (FBSR). A determination of the adequacy of the FBSR process to treat Hanford tank waste is required.more » The initial step in determining the adequacy of the FBSR process is to select archived waste samples from the 222-S Laboratory that will be used to test the FBSR process. Analyses of the selected samples will be required to confirm the samples meet the testing criteria.« less

Hydrogen generation utilizing integrated CO2 removal with steam reforming

DOEpatents

Duraiswamy, Kandaswamy; Chellappa, Anand S

2013-07-23

A steam reformer may comprise fluid inlet and outlet connections and have a substantially cylindrical geometry divided into reforming segments and reforming compartments extending longitudinally within the reformer, each being in fluid communication. With the fluid inlets and outlets. Further, methods for generating hydrogen may comprise steam reformation and material adsorption in one operation followed by regeneration of adsorbers in another operation. Cathode off-gas from a fuel cell may be used to regenerate and sweep the adsorbers, and the operations may cycle among a plurality of adsorption enhanced reformers to provide a continuous flow of hydrogen.

Production of hydrogen from biomass by catalytic steam reforming of fast pyrolysis oil

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

Czernik, S.; Wang, D.; Chornet, E.

1998-08-01

Hydrogen is the prototype of the environmentally cleanest fuel of interest for power generation using fuel cells and for transportation. The thermochemical conversion of biomass to hydrogen can be carried out through two distinct strategies: (a) gasification followed by water-gas shift conversion, and (b) catalytic steam reforming of specific fractions derived from fast pyrolysis and aqueous/steam processes of biomass. This paper presents the latter route that begins with fast pyrolysis of biomass to produce bio-oil. This oil (as a whole or its selected fractions) can be converted to hydrogen via catalytic steam reforming followed by a water-gas shift conversion step.more » Such a process has been demonstrated at the bench scale using model compounds, poplar oil aqueous fraction, and the whole pyrolysis oil with commercial Ni-based steam reforming catalysts. Hydrogen yields as high as 85% have been obtained. Catalyst initial activity can be recovered through regeneration cycles by steam or CO{sub 2} gasification of carbonaceous deposits.« less

Integrated solar thermochemical reaction system for steam methane reforming

DOE PAGES

Zheng, Feng; Diver, Rich; Caldwell, Dustin D.; ...

2015-06-05

Solar-aided upgrade of the energy content of fossil fuels, such as natural gas, can provide a near-term transition path towards a future solar-fuel economy and reduce carbon dioxide emission from fossil fuel consumption. Both steam and dry reforming a methane-containing fuel stream have been studied with concentrated solar power as the energy input to drive the highly endothermic reactions but the concept has not been demonstrated at a commercial scale. Under a current project with the U.S. Department of Energy, PNNL is developing an integrated solar thermochemical reaction system that combines solar concentrators with micro- and meso-channel reactors and heatmore » exchangers to accomplish more than 20% solar augment of methane higher heating value. The objective of our three-year project is to develop and prepare for commercialization such solar reforming system with a high enough efficiency to serve as the frontend of a conventional natural gas (or biogas) combined cycle power plant, producing power with a levelized cost of electricity less than 6¢/kWh, without subsidies, by the year 2020. In this paper, we present results from the first year of our project that demonstrated a solar-to-chemical energy conversion efficiency as high as 69% with a prototype reaction system.« less

Fuel cell integrated with steam reformer

DOEpatents

Beshty, Bahjat S.; Whelan, James A.

1987-01-01

A H.sub.2 -air fuel cell integrated with a steam reformer is disclosed wherein a superheated water/methanol mixture is fed to a catalytic reformer to provide a continuous supply of hydrogen to the fuel cell, the gases exhausted from the anode of the fuel cell providing the thermal energy, via combustion, for superheating the water/methanol mixture.

Thermodynamics and Transport Phenomena in High Temperature Steam Electrolysis Cells

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

James E. O'Brien

2012-03-01

Hydrogen can be produced from water splitting with relatively high efficiency using high temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high temperature process heat. The overall thermal-to-hydrogen efficiency for high temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. An overview of high temperature electrolysis technologymore » will be presented, including basic thermodynamics, experimental methods, heat and mass transfer phenomena, and computational fluid dynamics modeling.« less

Efficient utilization of greenhouse gases in a gas-to-liquids process combined with CO2/steam-mixed reforming and Fe-based Fischer-Tropsch synthesis.

PubMed

Zhang, Chundong; Jun, Ki-Won; Ha, Kyoung-Su; Lee, Yun-Jo; Kang, Seok Chang

2014-07-15

Two process models for carbon dioxide utilized gas-to-liquids (GTL) process (CUGP) mainly producing light olefins and Fischer-Tropsch (F-T) synthetic oils were developed by Aspen Plus software. Both models are mainly composed of a reforming unit, an F-T synthesis unit and a recycle unit, while the main difference is the feeding point of fresh CO2. In the reforming unit, CO2 reforming and steam reforming of methane are combined together to produce syngas in flexible composition. Meanwhile, CO2 hydrogenation is conducted via reverse water gas shift on the Fe-based catalysts in the F-T synthesis unit to produce hydrocarbons. After F-T synthesis, the unreacted syngas is recycled to F-T synthesis and reforming units to enhance process efficiency. From the simulation results, it was found that the carbon efficiencies of both CUGP options were successfully improved, and total CO2 emissions were significantly reduced, compared with the conventional GTL processes. The process efficiency was sensitive to recycle ratio and more recycle seemed to be beneficial for improving process efficiency and reducing CO2 emission. However, the process efficiency was rather insensitive to split ratio (recycle to reforming unit/total recycle), and the optimum split ratio was determined to be zero.

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.

Steam Hydrocarbon Cracking and Reforming

ERIC Educational Resources Information Center

Golombok, Michael

2004-01-01

The interactive methods of steam hydrocarbon reforming and cracking of the oil and chemical industries are scrutinized, with special focus on their resemblance and variations. The two methods are illustrations of equilibrium-controlled and kinetically-controlled processes, the analysis of which involves theories, which overlap and balance each…

Alternative technologies to steam-methane reforming

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

Tindall, B.M.; Crews, M.A.

1995-11-01

Steam-methane reforming (SMR) has been the conventional route for hydrogen and carbon monoxide production from natural gas feedstocks. However, several alternative technologies are currently finding favor for an increasing number of applications. The competing technologies include: steam-methane reforming combined with oxygen secondary reforming (SMR/O2R); autothermal reforming (ATR); thermal partial oxidation (POX). Each of these alternative technologies uses oxygen as a feedstock. Accordingly, if low-cost oxygen is available, they can be an attractive alternate to SMR with natural gas feedstocks. These technologies are composed technically and economically. The following conclusions can be drawn: (1) the SMR/O2R, ATR and POX technologies canmore » be attractive if low-cost oxygen is available; (2) for competing technologies, the H{sub 2}/CO product ratio is typically the most important process parameter; (3) for low methane slip, the SMR/O2R, ATR and POX technologies are favored; (4) for full CO{sub 2} recycle, POX is usually better than ATR; (5) relative to POX, the ATR is a nonlicensed technology that avoids third-party involvement; (6) economics of each technology are dependent on the conditions and requirements for each project and must be evaluated on a case-by-case basis.« less

High yields of hydrogen production from methanol steam reforming with a cross-U type reactor

PubMed Central

Zhang, Shubin; Chen, Junyu; Zhang, Xuelin; Liu, Xiaowei

2017-01-01

This paper presents a numerical and experimental study on the performance of a methanol steam reformer integrated with a hydrogen/air combustion reactor for hydrogen production. A CFD-based 3D model with mass and momentum transport and temperature characteristics is established. The simulation results show that better performance is achieved in the cross-U type reactor compared to either a tubular reactor or a parallel-U type reactor because of more effective heat transfer characteristics. Furthermore, Cu-based micro reformers of both cross-U and parallel-U type reactors are designed, fabricated and tested for experimental validation. Under the same condition for reforming and combustion, the results demonstrate that higher methanol conversion is achievable in cross-U type reactor. However, it is also found in cross-U type reactor that methanol reforming selectivity is the lowest due to the decreased water gas shift reaction under high temperature, thereby carbon monoxide concentration is increased. Furthermore, the reformed gas generated from the reactors is fed into a high temperature proton exchange membrane fuel cell (PEMFC). In the test of discharging for 4 h, the fuel cell fed by cross-U type reactor exhibits the most stable performance. PMID:29121067

High yields of hydrogen production from methanol steam reforming with a cross-U type reactor.

PubMed

Zhang, Shubin; Zhang, Yufeng; Chen, Junyu; Zhang, Xuelin; Liu, Xiaowei

2017-01-01

This paper presents a numerical and experimental study on the performance of a methanol steam reformer integrated with a hydrogen/air combustion reactor for hydrogen production. A CFD-based 3D model with mass and momentum transport and temperature characteristics is established. The simulation results show that better performance is achieved in the cross-U type reactor compared to either a tubular reactor or a parallel-U type reactor because of more effective heat transfer characteristics. Furthermore, Cu-based micro reformers of both cross-U and parallel-U type reactors are designed, fabricated and tested for experimental validation. Under the same condition for reforming and combustion, the results demonstrate that higher methanol conversion is achievable in cross-U type reactor. However, it is also found in cross-U type reactor that methanol reforming selectivity is the lowest due to the decreased water gas shift reaction under high temperature, thereby carbon monoxide concentration is increased. Furthermore, the reformed gas generated from the reactors is fed into a high temperature proton exchange membrane fuel cell (PEMFC). In the test of discharging for 4 h, the fuel cell fed by cross-U type reactor exhibits the most stable performance.

Macroporous Double-Network Hydrogel for High-Efficiency Solar Steam Generation Under 1 sun Illumination.

PubMed

Yin, Xiangyu; Zhang, Yue; Guo, Qiuquan; Cai, Xiaobing; Xiao, Junfeng; Ding, Zhifeng; Yang, Jun

2018-04-04

Solar steam generation is one of the most promising solar-energy-harvesting technologies to address the issue of water shortage. Despite intensive efforts to develop high-efficiency solar steam generation devices, challenges remain in terms of the relatively low solar thermal efficiency, complicated fabrications, high cost, and difficulty in scaling up. Herein, a double-network hydrogel with a porous structure (p-PEGDA-PANi) is demonstrated for the first time as a flexible, recyclable, and efficient photothermal platform for low-cost and scalable solar steam generation. As a novel photothermal platform, the p-PEGDA-PANi involves all necessary properties of efficient broadband solar absorption, exceptional hydrophilicity, low heat conductivity, and porous structure for high-efficiency solar steam generation. As a result, the hydrogel-based solar steam generator exhibits a maximum solar thermal efficiency of 91.5% with an evaporation rate of 1.40 kg m -2 h -1 under 1 sun illumination, which is comparable to state-of-the-art solar steam generation devices. Furthermore, the good durability and environmental stability of the p-PEGDA-PANi hydrogel enables a convenient recycling and reusing process toward real-life applications. The present research not only provides a novel photothermal platform for solar energy harvest but also opens a new avenue for the application of the hydrogel materials in solar steam generation.

Remarkable support effect on the reactivity of Pt/In2O3/MOx catalysts for methanol steam reforming

NASA Astrophysics Data System (ADS)

Liu, Xin; Men, Yong; Wang, Jinguo; He, Rong; Wang, Yuanqiang

2017-10-01

Effects of supports over Pt/In2O3/MOx catalysts with extremely low loading of Pt (1 wt%) and In2O3 loadings (3 wt%) are investigated for the hydrogen production of methanol steam reforming (MSR) in the temperature range of 250-400 °C. Under practical conditions without the pre-reduction, the 1Pt/3In2O3/CeO2 catalyst shows the highly efficient catalytic performance, achieving almost complete methanol conversion (98.7%) and very low CO selectivity of 2.6% at 325 °C. The supported Pt/In2O3 catalysts are characterized by means of Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), high-resolution transmission microscopy (HRTEM), temperature programmed reduction with hydrogen (H2-TPR), CO pulse chemisorption, temperature programmed desorption of methanol and water (CH3OH-TPD and H2O-TPD). These demonstrate that the nature of catalyst support of Pt/In2O3/MOx plays crucial roles in the Pt dispersion associated by the strong interaction among Pt, In2O3 and supporting materials and the surface redox properties at low temperature, and thus affects their capability to activate the reactants and determines the catalytic activity of methanol steam reforming. The superior 1Pt/3In2O3/CeO2 catalyst, exhibiting a remarkable reactivity and stability for 32 h on stream, demonstrates its potential for efficient hydrogen production of methanol steam reforming in mobile and de-centralized H2-fueled PEMFC systems.

High temperature ceramic-tubed reformer

NASA Astrophysics Data System (ADS)

Williams, Joseph J.; Rosenberg, Robert A.; McDonough, Lane J.

1990-03-01

The overall objective of the HiPHES project is to develop an advanced high-pressure heat exchanger for a convective steam/methane reformer. The HiPHES steam/methane reformer is a convective, shell and tube type, catalytic reactor. The use of ceramic tubes will allow reaction temperature higher than the current state-of-the-art outlet temperatures of about 1600 F using metal tubes. Higher reaction temperatures increase feedstock conversion to synthesis gas and reduce energy requirements compared to currently available radiant-box type reformers using metal tubes. Reforming of natural gas is the principal method used to produce synthesis gas (primarily hydrogen and carbon monoxide, H2 and CO) which is used to produce hydrogen (for refinery upgrading), methanol, as well as several other important materials. The HiPHES reformer development is an extension of Stone and Webster's efforts to develop a metal-tubed convective reformer integrated with a gas turbine cycle.

In-Space Propulsion, Logistics Reduction, and Evaluation of Steam Reformer Kinetics: Problems and Prospects

NASA Technical Reports Server (NTRS)

Jaworske, D. A.; Palaszewski, B. A.; Kulis, M. J.; Gokoglu, S. A.

2015-01-01

Human space missions generate waste materials. A 70-kg crewmember creates a waste stream of 1 kg per day, and a four-person crew on a deep space habitat for a 400+ day mission would create over 1600 kg of waste. Converted into methane, the carbon could be used as a fuel for propulsion or power. The NASA Advanced Exploration Systems (AES) Logistics Reduction and Repurposing (LRR) project is investing in space resource utilization with an emphasis on repurposing logistics materials for useful purposes and has selected steam reforming among many different competitive processes as the preferred method for repurposing organic waste into methane. Already demonstrated at the relevant processing rate of 5.4 kg of waste per day, high temperature oxygenated steam consumes waste and produces carbon dioxide, carbon monoxide, and hydrogen which can then be converted into methane catalytically. However, the steam reforming process has not been studied in microgravity. Data are critically needed to understand the mechanisms that allow use of steam reforming in a reduced gravity environment. This paper reviews the relevant literature, identifies gravity-dependent mechanisms within the steam gasification process, and describes an innovative experiment to acquire the crucial kinetic information in a small-scale reactor specifically designed to operate within the requirements of a reduced gravity aircraft flight. The experiment will determine if the steam reformer process is mass-transport limited, and if so, what level of forced convection will be needed to obtain performance comparable to that in 1-g.

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

Catalyst evaluation for high-purity H2 production by sorption-enhanced steam-methane reforming coupled to a Ca/Cu process

NASA Astrophysics Data System (ADS)

Navarro, M. V.; López, J. M.; García, T.; Grasa, G.; Murillo, R.

2017-09-01

The operational limits of a commercial nickel-based catalyst under the conditions of a sorption-enhanced steam-methane reforming process coupled to a Ca/Cu chemical loop are investigated for high-purity H2 production in a cyclic operation. The performance of the reforming catalyst is tested by means of a high number of oxidation-reduction-reforming cycles. After 100 oxidation-reduction cycles, this catalyst retains its exceptional reforming activity. The methane conversion values are close to the thermodynamic equilibrium under very demanding conditions: temperature between 500 °C - 700 °C and mass hourly space velocity of 8.8 kgCH4 h-1 kgcat-1. After 200 cycles, the sample shows reduction in its reforming activity in line with a lower dispersion of the Ni species. Sintering of Ni nanocrystals is evidenced during the oxidation-reduction multi-cycles. The performance of the catalyst after 200 oxidation-reduction cycles mixed with a CaO-based CO2 sorbent is studied under optimal conditions calculated for the sorption-enhanced reforming process coupled to a Ca/Cu cycle (temperature of 650 °C, steam/methane ratio of 4, sorbent/catalyst ratio of 4 and space velocity of 0.75 kgCH4 h-1 kgcat-1). Remarkably, an equilibrium value over 92 vol.% H2 concentration is achieved, highlighting this catalyst as a promising candidate for the next steps of the process development.

New Insights into Reaction Mechanisms of Ethanol Steam Reforming on Co-ZrO2

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

Sun, Junming; Karim, Ayman M.; Mei, Donghai

2015-01-01

The reaction pathway of ethanol steam reforming on Co-ZrO2 has been identified and the active sites associated with each step are proposed. Ethanol is converted to acetaldehyde and then to acetone, followed by acetone steam reforming. More than 90% carbon was found to follow this reaction pathway. N2-Sorption, X-ray Diffraction (XRD), Temperature Programmed Reduction (TPR), in situ X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy, as well as theoretical Density Functional Theory (DFT) calculations have been employed to identify the structure and functionality of the catalysts, which was further used to correlate their performance in ESR. It was found that metallicmore » cobalt is mainly responsible for the acetone steam reforming reactions; while, CoO and basic sites on the support play a key role in converting ethanol to acetone via dehydrogenation and condensation/ketonization reaction pathways. The current work provides fundamental understanding of the ethanol steam reforming reaction mechanisms on Co-ZrO2 catalysts and sheds light on the rational design of selective and durable ethanol steam reforming catalysts.« less

Production of synthetic fuels using syngas from a steam hydrogasification and reforming process

NASA Astrophysics Data System (ADS)

Raju, Arun Satheesh Kumar

This thesis is aimed at the research, optimization and development of a thermo-chemical process aimed at the production of synthesis gas (mixture of H2 and CO) with a flexible H2 to CO ratio using coupled steam hydrogasification and steam reforming processes. The steam hydrogasification step generates a product gas containing significant amounts of methane by gasifying a carbonaceous feed material with steam and internally generated H2. This product gas is converted to synthesis gas with an excess H2 to CO using the steam reformer. Research involving experimental and simulation work has been conducted on steam hydrogasification, steam reforming and the Fischer-Tropsch reaction. The Aspen Plus simulation tool has been used to develop a process model that can perform heat and mass balance calculations of the whole process using built-in reactor modules and an empirical FT model available in the literature. This model has been used to estimate optimum feed ratios and process conditions for specific feedstocks and products. Steam hydrogasification of coal and wood mixtures of varying coal to wood ratios has been performed in a stirred batch reactor. The carbon conversion of the feedstocks to gaseous products is around 60% at 700°C and 80% at 800°C. The coal to wood ratio of the feedstock does not exert a significant influence on the carbon conversion. The rates of formation of CO, CO 2 and CH4 during gasification have been calculated based on the experimental results using a simple kinetic model. Experimental research on steam reforming has been performed. It has been shown that temperature and the feed CO2/CH4 ratio play a dominant role in determining the product gas H2/CO ratio. Reforming of typical steam hydrogasification product-gas stream has been investigated over a commercial steam reforming catalyst. The results demonstrate that the combined use of steam hydrogasification process with a reformer can generate a synthesis gas with a predetermined H2/CO ratio

Gas-Phase Hydrodesulfurization of JP-8 Light Fraction Using Steam Reformate

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

Huang, Xiwen; King, David L.

2006-10-11

Gas phase hydrodesulfurization of JP-8 light fraction was investigated over CoMo/Al2O3 and NiMo/Al2O3 catalysts. Use of a light fraction provides a fuel that is more easily desulfurized, and allows the process to operate in the vapor phase. This study investigated the utilization of reformate (syngas) from a steam reformer rather than pure H2 as gas feed to HDS unit. This is consistent with what might be available to the military during operation in the field. Dry syngas functions almost as well as pure H2 in the HDS reaction, and sulfur levels below 5ppmw are readily obtained from a feed initiallymore » containing 320ppmw sulfur. Addition of steam at 40 vol% to the gas feed has a significant negative impact on HDS performance with CoMo/Al2O3, but only a small effect with NiMo/Al2O3. The impacts of various process conditions on S removal efficiency were examined and will be described.« less

Influence of geometry on pressure and velocity distribution in packed-bed methanol steam reforming reactor

NASA Astrophysics Data System (ADS)

Ivanović, Ivana; Sedmak, Aleksandar; Milošević, Miloš; Cvetković, Ivana; Pohar, Andrej; Likozar, Blaž

2017-07-01

The main tasks of this research is to propose several changes in the packed bed micro methanol steam reformer geometry in order to ensure its performance. The reformer is an integral part of the existing indirect internal reforming high temperature PEMFC and most of its geometry is already defined. The space for remodeling is very limited.

3D-Printed, All-in-One Evaporator for High-Efficiency Solar Steam Generation under 1 Sun Illumination.

PubMed

Li, Yiju; Gao, Tingting; Yang, Zhi; Chen, Chaoji; Luo, Wei; Song, Jianwei; Hitz, Emily; Jia, Chao; Zhou, Yubing; Liu, Boyang; Yang, Bao; Hu, Liangbing

2017-07-01

Using solar energy to generate steam is a clean and sustainable approach to addressing the issue of water shortage. The current challenge for solar steam generation is to develop easy-to-manufacture and scalable methods which can convert solar irradiation into exploitable thermal energy with high efficiency. Although various material and structure designs have been reported, high efficiency in solar steam generation usually can be achieved only at concentrated solar illumination. For the first time, 3D printing to construct an all-in-one evaporator with a concave structure for high-efficiency solar steam generation under 1 sun illumination is used. The solar-steam-generation device has a high porosity (97.3%) and efficient broadband solar absorption (>97%). The 3D-printed porous evaporator with intrinsic low thermal conductivity enables heat localization and effectively alleviates thermal dissipation to the bulk water. As a result, the 3D-printed evaporator has a high solar steam efficiency of 85.6% under 1 sun illumination (1 kW m -2 ), which is among the best compared with other reported evaporators. The all-in-one structure design using the advanced 3D printing fabrication technique offers a new approach to solar energy harvesting for high-efficiency steam generation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lightweight, Mesoporous, and Highly Absorptive All-Nanofiber Aerogel for Efficient Solar Steam Generation.

PubMed

Jiang, Feng; Liu, He; Li, Yiju; Kuang, Yudi; Xu, Xu; Chen, Chaoji; Huang, Hao; Jia, Chao; Zhao, Xinpeng; Hitz, Emily; Zhou, Yubing; Yang, Ronggui; Cui, Lifeng; Hu, Liangbing

2018-01-10

The global fresh water shortage has driven enormous endeavors in seawater desalination and wastewater purification; among these, solar steam generation is effective in extracting fresh water by efficient utilization of naturally abundant solar energy. For solar steam generation, the primary focus is to design new materials that are biodegradable, sustainable, of low cost, and have high solar steam generation efficiency. Here, we designed a bilayer aerogel structure employing naturally abundant cellulose nanofibrils (CNFs) as basic building blocks to achieve sustainability and biodegradability as well as employing a carbon nanotube (CNT) layer for efficient solar utilization with over 97.5% of light absorbance from 300 to 1200 nm wavelength. The ultralow density (0.0096 g/cm 3 ) of the aerogel ensures that minimal material is required, reducing the production cost while at the same time satisfying the water transport and thermal-insulation requirements due to its highly porous structure (99.4% porosity). Owing to its rationally designed structure and thermal-regulation performance, the bilayer CNF-CNT aerogel exhibits a high solar-energy conversion efficiency of 76.3% and 1.11 kg m -2 h -1 at 1 kW m -2 (1 Sun) solar irradiation, comparable or even higher than most of the reported solar steam generation devices. Therefore, the all-nanofiber aerogel presents a new route for designing biodegradable, sustainable, and scalable solar steam generation devices with superb performance.

A novel nano-Ni/SiO2 catalyst for hydrogen production from steam reforming of ethanol.

PubMed

Wu, Chunfei; Williams, Paul T

2010-08-01

Catalytic steam reforming of ethanol has been regarded as a promising way to produce hydrogen. However, catalytic deactivation is a key problem in the process. In this paper, a novel nano-Ni/SiO2 catalyst was prepared by a simple sol-gel method and compared to catalysts prepared by an impregnation method in relation to the steam reforming ethanol process. Good Ni dispersion and high BET surface areas (>700 m2 g(-1)) were obtained for sol-gel catalysts, whereas only 1 m2 g(-1) surface area was obtained for the Ni/SiO2 impregnation catalyst. The results of catalytic steam reforming of ethanol showed that about twice of the hydrogen production was produced with the Ni/SiO2 catalyst prepared by sol-gel (around 0.2 g h(-1)) compared with that prepared by impregnation (around 0.1 g h(-1)). The analysis of the used catalysts showed that 10Ni/SiO2-B and 20Ni/SiO2-B presented the highest stability, while other catalysts were fragmented into small pieces after the reforming process, especially the catalysts prepared by impregnation. A novel catalyst has been produced that has been shown to be effective in the production of hydrogen from the steam reforming of ethanol.

Internal combustion engine with thermochemical recuperation fed by ethanol steam reforming products - feasibility study

NASA Astrophysics Data System (ADS)

Cesana, O.; Gutman, M.; Shapiro, M.; Tartakovsky, L.

2016-08-01

This research analyses the performance of a spark ignition engine fueled by ethanol steam reforming products. The basic concept involves the use of the internal combustion engine's (ICE) waste heat to promote onboard reforming of ethanol. The reformer and the engine performance were simulated and analyzed using GT-Suite, Chem CAD and Matlab software. The engine performance with different compositions of ethanol reforming products was analyzed, in order to find the optimal working conditions of the ICE - reformer system. The analysis performed demonstrated the capability to sustain the endothermic reactions in the reformer and to reform the liquid ethanol to hydrogen-rich gaseous fuel using the heat of the exhaust gases. However, the required reformer's size is quite large: 39 x 89 x 73 cm, which makes a feasibility of its mounting on board a vehicle questionable. A comparison with ICE fed by gasoline or liquid ethanol doesn't show a potential of efficiency improvement, but can be considered as a tool of additional emissions reduction.

Effect of ZnO facet on ethanol steam reforming over Co/ZnO

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

Yu, Ning; Zhang, He; Davidson, Stephen D.

2016-01-01

The effects of ZnO facets on ethanol steam reforming (ESR) were investigated over Co/ZnO catalysts synthesized using ZnO with different fractions of (10-10) non-polar facet. Co supported on ZnO with a higher fraction of (10-10) non-polar facet shows higher C-C cleavage activity and higher selectivity to CO2 (lower selectivity to CO) compared with Co supported on ZnO with less (10-10) non-polar facet exposed. The improved ethanol steam reforming performances are attributed to the high fraction of metallic Co stabilized by the ZnO (10-10) non-polar facet, which enhanced C-C cleavage and water-gas-shift (WGS) activities.

Thermodynamic evaluation of hydrogen production via bioethanol steam reforming

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

Tasnadi-Asztalos, Zsolt; Cormos, Ana-Maria; Imre-Lucaci, Árpád

2013-11-13

In this article, a thermodynamic analysis for bioethanol steam reforming for hydrogen production is presented. Bioethanol is a newly proposed renewable energy carrier mainly produced from biomass fermentation. Reforming of bioethanol provides a promising method for hydrogen production from renewable resources. Steam reforming of ethanol (SRE) takes place under the action of a metal catalyst capable of breaking C-C bonds into smaller molecules. A large domain for the water/bioethanol molar ratio as well as the temperature and average pressure has been used in the present work. The interval of investigated temperature was 100-800°C, the pressure was in the range ofmore » 1-10 bar and the molar ratio was between 3-25. The variations of gaseous species concentration e.g. H{sub 2}, CO, CO{sub 2}, CH{sub 4} were analyzed. The concentrations of the main products (H{sub 2} and CO) at lower temperature are smaller than the ones at higher temperature due to by-products formation (methane, carbon dioxide, acetylene etc.). The concentration of H2 obtained in the process using high molar ratio (>20) is higher than the one at small molar ratio (near stoichiometric). When the pressure is increased the hydrogen concentration decreases. The results were compared with literature data for validation purposes.« less

Template-Assisted Wet-Combustion Synthesis of Fibrous Nickel-Based Catalyst for Carbon Dioxide Methanation and Methane Steam Reforming.

PubMed

Aghayan, M; Potemkin, D I; Rubio-Marcos, F; Uskov, S I; Snytnikov, P V; Hussainova, I

2017-12-20

Efficient capture and recycling of CO 2 enable not only prevention of global warming but also the supply of useful low-carbon fuels. The catalytic conversion of CO 2 into an organic compound is a promising recycling approach which opens new concepts and opportunities for catalytic and industrial development. Here we report about template-assisted wet-combustion synthesis of a one-dimensional nickel-based catalyst for carbon dioxide methanation and methane steam reforming. Because of a high temperature achieved in a short time during reaction and a large amount of evolved gases, the wet-combustion synthesis yields homogeneously precipitated nanoparticles of NiO with average particle size of 4 nm on alumina nanofibers covered with a NiAl 2 O 4 nanolayer. The as-synthesized core-shell structured fibers exhibit outstanding activity in steam reforming of methane and sufficient activity in carbon dioxide methanation with 100% selectivity toward methane formation. The as-synthesized catalyst shows stable operation under the reaction conditions for at least 50 h.

Ethanol internal steam reforming in intermediate temperature solid oxide fuel cell

NASA Astrophysics Data System (ADS)

Diethelm, Stefan; Van herle, Jan

This study investigates the performance of a standard Ni-YSZ anode supported cell under ethanol steam reforming operating conditions. Therefore, the fuel cell was directly operated with a steam/ethanol mixture (3 to 1 molar). Other gas mixtures were also used for comparison to check the conversion of ethanol and of reformate gases (H 2, CO) in the fuel cell. The electrochemical properties of the fuel cell fed with four different fuel compositions were characterized between 710 and 860 °C by I- V and EIS measurements at OCV and under polarization. In order to elucidate the limiting processes, impedance spectra obtained with different gas compositions were compared using the derivative of the real part of the impedance with respect of the natural logarithm of the frequency. Results show that internal steam reforming of ethanol takes place significantly on Ni-YSZ anode only above 760 °C. Comparisons of results obtained with reformate gas showed that the electrochemical cell performance is dominated by the conversion of hydrogen. The conversion of CO also occurs either directly or indirectly through the water-gas shift reaction but has a significant impact on the electrochemical performance only above 760 °C.

Effect of Cobalt Particle Size on Acetone Steam Reforming

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

Sun, Junming; Zhang, He; Yu, Ning

2015-06-11

Carbon-supported cobalt nanoparticles with different particle sizes were synthesized and characterized by complementary characterization techniques such as X-ray diffraction, N-2 sorption, acetone temperature-programmed desorption, transmission electron microscopy, and CO chemisorption. Using acetone steam reforming reaction as a probe reaction, we revealed a volcano-shape curve of the intrinsic activity (turnover frequency of acetone) and the CO2 selectivity as a function of the cobalt particle size with the highest activity and selectivity observed at a particle size of approximately 12.8nm. Our results indicate that the overall performance of acetone steam reforming is related to a combination of particle-size-dependent acetone decomposition, water dissociation,more » and the oxidation state of the cobalt nanoparticles.« less

Thermodynamic equilibrium calculations of dimethyl ether steam reforming and dimethyl ether hydrolysis

NASA Astrophysics Data System (ADS)

Semelsberger, Troy A.; Borup, Rodney L.

The production of a hydrogen-rich fuel-cell feed by dimethyl ether (DME) steam reforming was investigated using calculations of thermodynamic equilibrium as a function of steam-to-carbon ratio (0.00-4.00), temperature (100-600 °C), pressure (1-5 atm), and product species. Species considered were acetone, acetylene, carbon dioxide, carbon monoxide, dimethyl ether, ethane, ethanol, ethylene, formaldehyde, formic acid, hydrogen, isopropanol, methane, methanol, methyl-ethyl ether, n-propanol and water. Thermodynamic equilibrium calculations of DME steam reforming indicate complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide at temperatures greater than 200 °C and steam-to-carbon ratios greater than 1.25 at atmospheric pressure ( P = 1 atm). Increasing the operating pressure shifts the equilibrium toward the reactants; increasing the pressure from 1 to 5 atm decreases the conversion of dimethyl ether from 99.5 to 76.2%. The trend of thermodynamically stable products in decreasing mole fraction is methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol, methyl-ethyl ether and methanol-formaldehyde, formic acid, and acetylene were not observed. Based on the equilibrium calculations, the optimal processing conditions for dimethyl ether steam reforming occur at a steam-to-carbon ratio of 1.50, a pressure of 1 atm, and a temperature of 200 °C. These thermodynamic equilibrium calculations show dimethyl ether processed with steam will produce hydrogen-rich fuel-cell feeds—with hydrogen concentrations exceeding 70%. The conversion of dimethyl ether via hydrolysis (considering methanol as the only product) is limited by thermodynamic equilibrium. Equilibrium conversion increases with temperature and steam-to-carbon ratio. A maximum dimethyl ether conversion of 62% is achieved at a steam-to-carbon ratio of 5.00 and a processing temperature of 600 °C.

Studies of potassium-promoted nickel catalysts for methane steam reforming: Effect of surface potassium location

NASA Astrophysics Data System (ADS)

Borowiecki, Tadeusz; Denis, Andrzej; Rawski, Michał; Gołębiowski, Andrzej; Stołecki, Kazimierz; Dmytrzyk, Jaromir; Kotarba, Andrzej

2014-05-01

The effect of potassium addition to the Ni/Al2O3 steam reforming catalyst has been investigated on several model systems, including K/Al2O3 with various amounts of alkali promoters (1-4 wt% of K2O), a model catalyst 90%NiO-10%Al2O3 promoted with potassium and a commercial catalyst. The potassium surface state and stability were investigated by means of the Species Resolved Thermal Alkali Desorption method (SR-TAD). The activity of the catalysts in the steam reforming of methane and their coking-resistance were also evaluated. The results reveal that the beneficial effect of potassium addition is strongly related to its location in the catalysts. The catalyst surface should be promoted with potassium in order to obtain high coking-resistant catalysts. Moreover, the catalyst preparation procedure should ensure a direct interaction of potassium with the Al2O3 support surface. Due to the low stability of potassium on θ-Al2O3 this phase is undesirable during the preparation of a stable steam reforming catalyst.

Wood-Graphene Oxide Composite for Highly Efficient Solar Steam Generation and Desalination.

PubMed

Liu, Keng-Ku; Jiang, Qisheng; Tadepalli, Sirimuvva; Raliya, Ramesh; Biswas, Pratim; Naik, Rajesh R; Singamaneni, Srikanth

2017-03-01

Solar steam generation is a highly promising technology for harvesting solar energy, desalination and water purification. We introduce a novel bilayered structure composed of wood and graphene oxide (GO) for highly efficient solar steam generation. The GO layer deposited on the microporous wood provides broad optical absorption and high photothermal conversion resulting in rapid increase in the temperature at the liquid surface. On the other hand, wood serves as a thermal insulator to confine the photothermal heat to the evaporative surface and to facilitate the efficient transport of water from the bulk to the photothermally active space. Owing to the tailored bilayer structure and the optimal thermo-optical properties of the individual components, the wood-GO composite structure exhibited a solar thermal efficiency of ∼83% under simulated solar excitation at a power density of 12 kW/m 2 . The novel composite structure demonstrated here is highly scalable and cost-efficient, making it an attractive material for various applications involving large light absorption, photothermal conversion and heat localization.

High Efficiency Solar-based Catalytic Structure for CO 2 Reforming

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

Menkara, Hisham

Throughout this project, we developed and optimized various photocatalyst structures for CO 2 reforming into hydrocarbon fuels and various commodity chemical products. We also built several closed-loop and continuous fixed-bed photocatalytic reactor system prototypes for a larger-scale demonstration of CO 2 reforming into hydrocarbons, mainly methane and formic acid. The results achieved have indicated that with each type of reactor and structure, high reforming yields can be obtained by refining the structural and operational conditions of the reactor, as well as by using various sacrificial agents (hole scavengers). We have also demonstrated, for the first time, that an aqueous solutionmore » containing acid whey (a common bio waste) is a highly effective hole scavenger for a solar-based photocatalytic reactor system and can help reform CO 2 into several products at once. The optimization tasks performed throughout the project have resulted in efficiency increase in our conventional reactors from an initial 0.02% to about 0.25%, which is 10X higher than our original project goal. When acid whey was used as a sacrificial agent, the achieved energy efficiency for formic acid alone was ~0.4%, which is 16X that of our original project goal and higher than anything ever reported for a solar-based photocatalytic reactor. Therefore, by carefully selecting sacrificial agents, it should be possible to reach energy efficiency in the range of the photosynthetic efficiency of typical crop and biofuel plants (1-3%).« less

Stable hydrogen production from ethanol through steam reforming reaction over nickel-containing smectite-derived catalyst.

PubMed

Yoshida, Hiroshi; Yamaoka, Ryohei; Arai, Masahiko

2014-12-25

Hydrogen production through steam reforming of ethanol was investigated with conventional supported nickel catalysts and a Ni-containing smectite-derived catalyst. The former is initially active, but significant catalyst deactivation occurs during the reaction due to carbon deposition. Side reactions of the decomposition of CO and CH4 are the main reason for the catalyst deactivation, and these reactions can relatively be suppressed by the use of the Ni-containing smectite. The Ni-containing smectite-derived catalyst contains, after H2 reduction, stable and active Ni nanocrystallites, and as a result, it shows a stable and high catalytic performance for the steam reforming of ethanol, producing H2.

Stable Hydrogen Production from Ethanol through Steam Reforming Reaction over Nickel-Containing Smectite-Derived Catalyst

PubMed Central

Yoshida, Hiroshi; Yamaoka, Ryohei; Arai, Masahiko

2014-01-01

Hydrogen production through steam reforming of ethanol was investigated with conventional supported nickel catalysts and a Ni-containing smectite-derived catalyst. The former is initially active, but significant catalyst deactivation occurs during the reaction due to carbon deposition. Side reactions of the decomposition of CO and CH4 are the main reason for the catalyst deactivation, and these reactions can relatively be suppressed by the use of the Ni-containing smectite. The Ni-containing smectite-derived catalyst contains, after H2 reduction, stable and active Ni nanocrystallites, and as a result, it shows a stable and high catalytic performance for the steam reforming of ethanol, producing H2. PMID:25547495

Conceptual Design of Low-Temperature Hydrogen Production and High-Efficiency Nuclear Reactor Technology

NASA Astrophysics Data System (ADS)

Fukushima, Kimichika; Ogawa, Takashi

Hydrogen, a potential alternative energy source, is produced commercially by methane (or LPG) steam reforming, a process that requires high temperatures, which are produced by burning fossil fuels. However, as this process generates large amounts of CO2, replacement of the combustion heat source with a nuclear heat source for 773-1173K processes has been proposed in order to eliminate these CO2 emissions. In this paper, a novel method of nuclear hydrogen production by reforming dimethyl ether (DME) with steam at about 573K is proposed. From a thermodynamic equilibrium analysis of DME steam reforming, the authors identified conditions that provide high hydrogen production fraction at low pressure and temperatures of about 523-573K. By setting this low-temperature hydrogen production process upstream from a turbine and nuclear reactor at about 573K, the total energy utilization efficiency according to equilibrium mass and heat balance analysis is about 50%, and it is 75%for a fast breeder reactor (FBR), where turbine is upstream of the reformer.

Internal reforming of methane in solid oxide fuel cell systems

NASA Astrophysics Data System (ADS)

Peters, R.; Dahl, R.; Klüttgen, U.; Palm, C.; Stolten, D.

Internal reforming is an attractive option offering a significant cost reduction, higher efficiencies and faster load response of a solid oxide fuel cell (SOFC) power plant. However, complete internal reforming may lead to several problems which can be avoided with partial pre-reforming of natural gas. In order to achieve high total plant efficiency associated with low energy consumption and low investment costs, a process concept has been developed based on all the components of the SOFC system. In the case of anode gas recycling an internal steam circuit exists. This has the advantage that there is no need for an external steam generator and the steam concentration in the anode gas is reduced. However, anode gas recycling has to be proven by experiments in a pre-reformer and for internal reforming. The addition of carbon dioxide clearly shows a decrease in catalyst activity, while for temperatures higher than 1000 K hydrogen leads to an increase of the measured methane conversion rates.

Catalytic EGR-Loop Reforming for High Efficiency in a Stoichiometric SI Engine through TCR and Dilution Limit Extension. 1. Catalyst Performance and Fuel Effects

DOE PAGES

Chang, Yan; Szybist, James P.; Pihl, Josh A.; ...

2017-12-19

The use of fuel reformate from catalytic processes is known to have beneficial effects on the spark-ignited (SI) combustion process through enhanced dilution tolerance and decreased combustion duration, but in many cases reformate generation can incur a significant fuel penalty. Here, in this two-part investigation, we demonstrate that efficient catalytic fuel reforming can result in improved brake engine efficiency while maintaining stoichiometric exhaust under the right conditions. In part one of this investigation, we used a combination of thermodynamic equilibrium calculations and experimental fuel catalytic reforming measurements on an engine to characterize the best possible reforming performance and energetics overmore » a range of equivalence ratios and O 2 concentrations. Ideally, one might expect the highest levels of thermochemical recuperation for the highest catalyst equivalence ratios. However, reforming under these conditions is highly endothermic, and the available enthalpy for reforming is constrained. Thus for relatively high equivalence ratios, more methane and less H 2 and CO are produced. Our experiments revealed that this suppression of H 2 and CO could be countered by adding small amounts of O 2, yielding as much as 15 vol % H 2 at the catalyst outlet for 4 < Φ catalyst < 7 under quasi-steady-state conditions. Under these conditions the H 2 and CO yields were highest and there was significant water consumption, confirming the presence of steam reforming reactions. Analyses of the experimental catalyst measurements indicated the possibility of both endothermic and exothermic reaction stages and global reaction rates sufficient to enable the utilization of higher space velocities than those employed in our experiments. Finally, in a companion paper detailing part two of this investigation, we present results for the engine dilution tolerance and brake engine efficiency impacts of the reforming levels achieved.« less

Catalytic EGR-Loop Reforming for High Efficiency in a Stoichiometric SI Engine through TCR and Dilution Limit Extension. 1. Catalyst Performance and Fuel Effects

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

Chang, Yan; Szybist, James P.; Pihl, Josh A.

The use of fuel reformate from catalytic processes is known to have beneficial effects on the spark-ignited (SI) combustion process through enhanced dilution tolerance and decreased combustion duration, but in many cases reformate generation can incur a significant fuel penalty. Here, in this two-part investigation, we demonstrate that efficient catalytic fuel reforming can result in improved brake engine efficiency while maintaining stoichiometric exhaust under the right conditions. In part one of this investigation, we used a combination of thermodynamic equilibrium calculations and experimental fuel catalytic reforming measurements on an engine to characterize the best possible reforming performance and energetics overmore » a range of equivalence ratios and O 2 concentrations. Ideally, one might expect the highest levels of thermochemical recuperation for the highest catalyst equivalence ratios. However, reforming under these conditions is highly endothermic, and the available enthalpy for reforming is constrained. Thus for relatively high equivalence ratios, more methane and less H 2 and CO are produced. Our experiments revealed that this suppression of H 2 and CO could be countered by adding small amounts of O 2, yielding as much as 15 vol % H 2 at the catalyst outlet for 4 < Φ catalyst < 7 under quasi-steady-state conditions. Under these conditions the H 2 and CO yields were highest and there was significant water consumption, confirming the presence of steam reforming reactions. Analyses of the experimental catalyst measurements indicated the possibility of both endothermic and exothermic reaction stages and global reaction rates sufficient to enable the utilization of higher space velocities than those employed in our experiments. Finally, in a companion paper detailing part two of this investigation, we present results for the engine dilution tolerance and brake engine efficiency impacts of the reforming levels achieved.« less

Differences in the Nature of Active Sites for Methane Dry Reforming and Methane Steam Reforming over Nickel Aluminate Catalysts

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

Rogers, Jessica L.; Mangarella, Michael C.; D’Amico, Andrew D.

In this paper, the Pechini synthesis was used to prepare nickel aluminate catalysts with the compositions NiAl 4O 7, NiAl 2O 4, and Ni 2Al 2O 5. The samples have been characterized by N 2 physisorption, temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and X-ray absorption spectroscopy (XAS). Characterization results indicate unique structural properties and excellent regeneration potential of nickel aluminates. Prepared samples were tested when unreduced and reduced prior to reaction for methane dry reforming and methane steam reforming reactivity. NiAl 2O 4 in the reduced and unreduced statemore » as well as NiAl 4O 7 in the reduced state are active and stable for methane dry reforming due to the presence of 4-fold coordinated oxidized nickel. The limited amount of metallic nickel in these samples minimizes carbon deposition. Finally, on the other hand, the presence of metallic nickel is required for methane steam reforming. Ni 2Al 2O 5 in the reduced and unreduced states and NiAl 2O 4 in the reduced state are found to be active for methane steam reforming due to the presence of sufficiently small nickel nanoparticles that catalyze the reaction without accumulating carbonaceous deposits.« less

Differences in the Nature of Active Sites for Methane Dry Reforming and Methane Steam Reforming over Nickel Aluminate Catalysts

DOE PAGES

Rogers, Jessica L.; Mangarella, Michael C.; D’Amico, Andrew D.; ...

2016-07-20

In this paper, the Pechini synthesis was used to prepare nickel aluminate catalysts with the compositions NiAl 4O 7, NiAl 2O 4, and Ni 2Al 2O 5. The samples have been characterized by N 2 physisorption, temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and X-ray absorption spectroscopy (XAS). Characterization results indicate unique structural properties and excellent regeneration potential of nickel aluminates. Prepared samples were tested when unreduced and reduced prior to reaction for methane dry reforming and methane steam reforming reactivity. NiAl 2O 4 in the reduced and unreduced statemore » as well as NiAl 4O 7 in the reduced state are active and stable for methane dry reforming due to the presence of 4-fold coordinated oxidized nickel. The limited amount of metallic nickel in these samples minimizes carbon deposition. Finally, on the other hand, the presence of metallic nickel is required for methane steam reforming. Ni 2Al 2O 5 in the reduced and unreduced states and NiAl 2O 4 in the reduced state are found to be active for methane steam reforming due to the presence of sufficiently small nickel nanoparticles that catalyze the reaction without accumulating carbonaceous deposits.« less

Advances in catalysts for internal reforming in high temperature fuel cells

NASA Astrophysics Data System (ADS)

Dicks, A. L.

Catalytic steam reforming of natural gas is an attractive method of producing the hydrogen required by the present generation of fuel cells. The molten carbonate (MCFC) and solid oxide (SOFC) fuel cells operate at high enough temperatures for the endothermic steam reforming reaction to be carried out within the stack. For the MCFC, the conventional anodes have insufficient activity to catalyse the steam reforming of natural gas. For these cells, internal reforming can be achieved only with the addition of a separate catalyst, preferably located in close proximity to the anode. However, in the so-called `Direct Internal Reforming' configuration, attack from alkali in the MCFC may severely limit catalyst lifetime. In the case of the state-of-the-art SOFC, natural gas can be reformed directly on the nickel cermet anode. However, in the SOFC, temperature variations in the cell caused by the reforming reaction may limit the amount of internal reforming that can be allowed in practice. In addition, some external pre-reforming may be desirable to remove high molecular weight hydrocarbons from the fuel gas, which would otherwise crack to produce elemental carbon. Degradation of the SOFC anode may also be a problem when internal reforming is carried out. This has prompted several research groups to investigate the use of alternative anode materials.

Application of Flexible Micro Temperature Sensor in Oxidative Steam Reforming by a Methanol Micro Reformer

PubMed Central

Lee, Chi-Yuan; Lee, Shuo-Jen; Shen, Chia-Chieh; Yeh, Chuin-Tih; Chang, Chi-Chung; Lo, Yi-Man

2011-01-01

Advances in fuel cell applications reflect the ability of reformers to produce hydrogen. This work presents a flexible micro temperature sensor that is fabricated based on micro-electro-mechanical systems (MEMS) technology and integrated into a flat micro methanol reformer to observe the conditions inside that reformer. The micro temperature sensor has higher accuracy and sensitivity than a conventionally adopted thermocouple. Despite various micro temperature sensor applications, integrated micro reformers are still relatively new. This work proposes a novel method for integrating micro methanol reformers and micro temperature sensors, subsequently increasing the methanol conversion rate and the hydrogen production rate by varying the fuel supply rate and the water/methanol ratio. Importantly, the proposed micro temperature sensor adequately controls the interior temperature during oxidative steam reforming of methanol (OSRM), with the relevant parameters optimized as well. PMID:22319407

Hydrogen production by ethanol steam reforming on Ni/oxide catalysts

NASA Astrophysics Data System (ADS)

Lazar, Mihaela D.; Dan, Monica; Mihet, Maria; Borodi, George; Almasan, Valer

2012-02-01

Hydrogen production from bio-fuels such as bio-ethanol provides significant environmental benefits since the resulted CO2 is consumed again for biomass growth, offering a carbon dioxide neutral energy source. In the actual conditions of increasing energy demand and atmosphere pollution, clean produced hydrogen can be an alternative option for a clean energy vector. In this paper we present the results obtained in hydrogen production by steam reforming of ethanol using oxide supported nickel catalysts. Although Ni is not the most active catalyst for this process, economically is the most attractive one, due to the high price and low availability of noble metals. Ni was dispersed on several oxides: ZrO2, Al2O3, Cr2O3, SiO2 with a target metal concentration of 8 wt%. using impregnation method. The catalysts were characterized using several techniques: N2 adsorption desorption isotherms to determine total surface area and porosity, XRD to determine oxide crystallinity and Ni crystallite size. Each catalyst was tested in steam reforming of ethanol at temperatures ranging from 150 to 350°C, at atmospheric pressure and a ethanol: steam ratio of 1:9. The best ethanol conversion and catalyst stability was obtained for Ni/Al2O3. The catalyst selectivity for H2 production depends on the support nature. The best H2 selectivity was obtained for Ni/ZrO2 catalyst.

HIGH EFFICIENCY SYNGAS GENERATION

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

Robert J. Copeland; Yevgenia Gershanovich; Brian Windecker

2005-02-01

This project investigated an efficient and low cost method of auto-thermally reforming natural gas to hydrogen and carbon monoxide. Reforming is the highest cost step in producing products such as methanol and Fisher Tropsch liquids (i.e., gas to liquids); and reducing the cost of reforming is the key to reducing the cost of these products. Steam reforming is expensive because of the high cost of the high nickel alloy reforming tubes (i.e., indirectly fired reforming tubes). Conventional auto-thermal or Partial Oxidation (POX) reforming minimizes the size and cost of the reformers and provides a near optimum mixture of CO andmore » hydrogen. However POX requires pure oxygen, which consumes power and significantly increases the cost to reforming. Our high efficiency process extracts oxygen from low-pressure air with novel oxygen sorbent and transfers the oxygen to a nickel-catalyzed reformer. The syngas is generated at process pressure (typically 20 to 40 bar) without nitrogen dilution and has a 1CO to 2H{sub 2} ratio that is near optimum for the subsequent production of Fisher-Tropsch liquid to liquids and other chemicals (i.e., Gas to Liquids, GTL). Our high process efficiency comes from the way we transfer the oxygen into the reformer. All of the components of the process, except for the oxygen sorbent, are commonly used in commercial practice. A process based on a longlived, regenerable, oxygen transfer sorbent could substantially reduce the cost of natural gas reforming to syngas. Lower cost syngas (CO + 2H{sub 2}) that is the feedstock for GTL would reduce the cost of GTL and for other commercial applications (e.g., methanol, other organic chemicals). The vast gas resources of Alaska's North Slope (ANS) offer more than 22 Tcf of gas and GTL production in this application alone, and could account for as much as 300,000 to 700,000 bpd for 20 to 30+ years. We developed a new sorbent, which is an essential part of the High Efficiency Oxygen Process (HOP). We

Alkali Metal CO2 Sorbents and the Resulting Metal Carbonates: Potential for Process Intensification of Sorption-Enhanced Steam Reforming.

PubMed

Memon, Muhammad Zaki; Zhao, Xiao; Sikarwar, Vineet Singh; Vuppaladadiyam, Arun K; Milne, Steven J; Brown, Andy P; Li, Jinhui; Zhao, Ming

2017-01-03

Sorption-enhanced steam reforming (SESR) is an energy and cost efficient approach to produce hydrogen with high purity. SESR makes it economically feasible to use a wide range of feedstocks for hydrogen production such as methane, ethanol, and biomass. Selection of catalysts and sorbents plays a vital role in SESR. This article reviews the recent research aimed at process intensification by the integration of catalysis and chemisorption functions into a single material. Alkali metal ceramic powders, including Li 2 ZrO 3 , Li 4 SiO 4 and Na 2 ZrO 3 display characteristics suitable for capturing CO 2 at low concentrations (<15% CO 2 ) and high temperatures (>500 °C), and thus are applicable to precombustion technologies such as SESR, as well as postcombustion capture of CO 2 from flue gases. This paper reviews the progress made in improving the operational performance of alkali metal ceramics under conditions that simulate power plant and SESR operation, by adopting new methods of sorbent synthesis and doping with additional elements. The paper also discusses the role of carbonates formed after in situ CO 2 chemisorption during a steam reforming process in respect of catalysts for tar cracking.

Mushrooms as Efficient Solar Steam-Generation Devices.

PubMed

Xu, Ning; Hu, Xiaozhen; Xu, Weichao; Li, Xiuqiang; Zhou, Lin; Zhu, Shining; Zhu, Jia

2017-07-01

Solar steam generation is emerging as a promising technology, for its potential in harvesting solar energy for various applications such as desalination and sterilization. Recent studies have reported a variety of artificial structures that are designed and fabricated to improve energy conversion efficiencies by enhancing solar absorption, heat localization, water supply, and vapor transportation. Mushrooms, as a kind of living organism, are surprisingly found to be efficient solar steam-generation devices for the first time. Natural and carbonized mushrooms can achieve ≈62% and ≈78% conversion efficiencies under 1 sun illumination, respectively. It is found that this capability of high solar steam generation is attributed to the unique natural structure of mushroom, umbrella-shaped black pileus, porous context, and fibrous stipe with a small cross section. These features not only provide efficient light absorption, water supply, and vapor escape, but also suppress three components of heat losses at the same time. These findings not only reveal the hidden talent of mushrooms as low-cost materials for solar steam generation, but also provide inspiration for the future development of high-performance solar thermal conversion devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enviro-Friendly Hydrogen Generation from Steel Mill-Scale via Metal-Steam Reforming

ERIC Educational Resources Information Center

Azad, Abdul-Majeed; Kesavan, Sathees

2006-01-01

An economically viable and environmental friendly method of generating hydrogen for fuel cells is by the reaction of certain metals with steam, called metal-steam reforming (MSR). This technique does not generate any toxic by-products nor contributes to the undesirable greenhouse effect. From the standpoint of favorable thermodynamics, total…

Single Step Bi-reforming and Oxidative Bi-reforming of Methane (Natural Gas) with Steam and Carbon Dioxide to Metgas (CO-2H2) for Methanol Synthesis: Self-Sufficient Effective and Exclusive Oxygenation of Methane to Methanol with Oxygen.

PubMed

Olah, George A; Goeppert, Alain; Czaun, Miklos; Mathew, Thomas; May, Robert B; Prakash, G K Surya

2015-07-15

Catalysts based on suitable metal oxide supports, such as NiO/MgO and CoO/MgO, were shown to be active for single step bi-reforming, the combined steam and dry reforming of methane or natural gas with H2O and CO2 exclusively to metgas (CO-2H2) for efficient methanol synthesis. Reactions were carried out in a tubular flow reactor under pressures up to 42 bar at 830-910 °C. Using a CH4 to steam to CO2 ratio of ∼3:2:1 in the gas feed, the H2/CO ratio of 2:1 was achieved, which is desired for subsequent methanol synthesis. The needed 2/1 steam/CO2 feed ratio together with the reaction heat for the endothermic bi-reforming can be conveniently obtained by the complete combustion of a quarter part of the overall used methane (natural gas) with oxygen of the air (oxidative bi-reforming). Complete combustion of a part of methane followed by bi-reforming leads to the production of metgas (H2/CO in 2:1 mol ratio) for self-sufficient exclusive methanol synthesis. The long sought after but elusive efficient and selective oxygenation of methane to methanol is thus achieved in an effective and economic way without any oxidation byproduct formation according to CH4 + 1/2O2 → CH3OH.

High-efficiency power production from natural gas with carbon capture

NASA Astrophysics Data System (ADS)

Adams, Thomas A.; Barton, Paul I.

A unique electricity generation process uses natural gas and solid oxide fuel cells at high electrical efficiency (74%HHV) and zero atmospheric emissions. The process contains a steam reformer heat-integrated with the fuel cells to provide the heat necessary for reforming. The fuel cells are powered with H 2 and avoid carbon deposition issues. 100% CO 2 capture is achieved downstream of the fuel cells with very little energy penalty using a multi-stage flash cascade process, where high-purity water is produced as a side product. Alternative reforming techniques such as CO 2 reforming, autothermal reforming, and partial oxidation are considered. The capital and energy costs of the proposed process are considered to determine the levelized cost of electricity, which is low when compared to other similar carbon capture-enabled processes.

Solid oxide fuel cell steam reforming power system

DOEpatents

Chick, Lawrence A.; Sprenkle, Vincent L.; Powell, Michael R.; Meinhardt, Kerry D.; Whyatt, Greg A.

2013-03-12

The present invention is a Solid Oxide Fuel Cell Reforming Power System that utilizes adiabatic reforming of reformate within this system. By utilizing adiabatic reforming of reformate within the system the system operates at a significantly higher efficiency than other Solid Oxide Reforming Power Systems that exist in the prior art. This is because energy is not lost while materials are cooled and reheated, instead the device operates at a higher temperature. This allows efficiencies higher than 65%.

Steam Reforming of Methyl Fuel - Phase I

DTIC Science & Technology

1977-06-30

best catalyst . 2.0 TEST DESCRIPTION 2.1 Technical Background The basic reactions occurring in steam reforming of methanol are CH3OH + H20 CO2 + 3H 2...chamber contains the test catalyst . The fuel feed tank was filled with premixed methanol /gasoline mixture. Fuel flow as well as water flow were measured...carbon-oxygen bond formation and therefore follows a different mechanism than the methanol reaction . Different catalysts promote these types of

Process and apparatus for the production of hydrogen by steam reforming of hydrocarbon

DOEpatents

Sircar, Shivaji; Hufton, Jeffrey Raymond; Nataraj, Shankar

2000-01-01

In the steam reforming of hydrocarbon, particularly methane, under elevated temperature and pressure to produce hydrogen, a feed of steam and hydrocarbon is fed into a first reaction volume containing essentially only reforming catalyst to partially reform the feed. The balance of the feed and the reaction products of carbon dioxide and hydrogen are then fed into a second reaction volume containing a mixture of catalyst and adsorbent which removes the carbon dioxide from the reaction zone as it is formed. The process is conducted in a cycle which includes these reactions followed by countercurrent depressurization and purge of the adsorbent to regenerate it and repressurization of the reaction volumes preparatory to repeating the reaction-sorption phase of the cycle.

Minimizing the formation of coke and methane on Co nanoparticles in steam reforming of biomass-derived oxygenates

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

Sun, Junming; Mei, Donghai; Karim, Ayman M.

2013-06-01

Fundamental understanding and control of chemical transformations are essential to the development of technically feasible and economically viable catalytic processes for efficient conversion of biomass to fuels and chemicals. Using an integrated experimental and theoretical approach, we report high hydrogen selectivity and catalyst durability of acetone steam reforming (ASR) on inert carbon supported Co nanoparticles. The observed catalytic performance is further elucidated on the basis of comprehensive first-principles calculations. Instead of being considered as an undesired intermediate prone for catalyst deactivation during bioethanol steam reforming (ESR), acetone is suggested as a key and desired intermediate in proposed two-stage ESR processmore » that leads to high hydrogen selectivity and low methane formation on Co-based catalysts. The significance of the present work also sheds a light on controlling the chemical transformations of key intermediates in biomass conversion such as ketones. We gratefully acknowledge the financial support from U. S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, and the Laboratory directed research and development (LDRD) project of Pacific Northwest National Laboratory (PNNL). Computing time was granted by the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL). The EMSL is a U.S. DOE national scientific user facility located at PNNL, and sponsored by the U.S. DOE’s Office of Biological and Environmental Research.« less

Structural and surface changes of cobalt modified manganese oxide during activation and ethanol steam reforming reaction

NASA Astrophysics Data System (ADS)

Gac, Wojciech; Greluk, Magdalena; Słowik, Grzegorz; Turczyniak-Surdacka, Sylwia

2018-05-01

Surface and structural changes of unmodified manganese and cobalt-manganese oxide during activation and ethanol steam reforming reaction conditions (ESR) were studied by means of X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction/oxidation (TPR/TPO) and transmission electron microscopy. It was shown that synthesis of cobalt manganese oxide by the redox precipitation method led to the formation of strongly dispersed cobalt ionic species within cryptomelane-based manganese oxide structure. Development of large cube-like MnO nanoparticles with spherical cobalt metallic crystallites decorated by manganese oxide on the high oxidation state and potassium species was observed during reduction. Cobalt manganese catalyst showed high initial activity and selectivity to H2 and CO2 in ethanol stem reforming reaction in the range of 390-480 °C. The drop of ethanol conversion and changes of selectivity with the time-on-stream were observed. An increase of reaction temperature led to intensification of deactivation phenomena. TEM studies evidenced coexistence of Co and CoOx nanoparticles formed under ethanol steam reforming conditions, partially covered by filamentous and encapsulating carbonaceous deposits.

CATALYTIC STEAM REFORMING OF CHLOROCARBONS: METHLYCHLORIDE. (R822721C633)

EPA Science Inventory

The effective destruction of trichloroethane, trichloroethylene and perchloroethylene by steam reforming with a commercial nickel catalyst has been demonstrated. Conversion levels of up to 0.99999 were attained in both laboratory and semi-pilot experiments, with the products c...

Hydrogen Production by Steam Reforming of Natural Gas Over Vanadium-Nickel-Alumina Catalysts.

PubMed

Yoo, Jaekyeong; Park, Seungwon; Song, Ji Hwan; Song, In Kyu

2018-09-01

A series of vanadium-nickel-alumina (xVNA) catalysts were prepared by a single-step sol-gel method with a variation of vanadium content (x, wt%) for use in the hydrogen production by steam reforming of natural gas. The effect of vanadium content on the physicochemical properties and catalytic activities of xVNA catalysts in the steam reforming of natural gas was investigated. It was found that natural gas conversion and hydrogen yield showed volcano-shaped trends with respect to vanadium content. It was also revealed that natural gas conversion and hydrogen yield increased with decreasing nickel crystallite size.

Study of Catalyst Variation Effect in Glycerol Conversion Process to Hydrogen Gas by Steam Reforming

NASA Astrophysics Data System (ADS)

Widayat; Hartono, R.; Elizabeth, E.; Annisa, A. N.

2018-04-01

Along with the economic development, needs of energy being increase too. Hydrogen as alternative energy has many usages. Besides that, hydrogen is one source of energy that is a clean fuel, but process production of hydrogen from natural gas as a raw material has been used for a long time. Therefore, there is need new invention to produce hydrogen from the others raw material. Glycerol, a byproduct of biodiesel production, is a compound which can be used as a raw material for hydrogen production. By using glycerol as a raw material of hydrogen production, we can get added value of glycerol as well as an energy source solution. The process production of hydrogen by steam reforming is a thermochemical process with efficiency 70%. This process needs contribution of catalyst to improve its efficiency and selectivity of the process. In this study will be examined the effect variation of catalyst for glycerol conversion process to hydrogen by steam reforming. The method for catalyst preparation was variation of catalyst impregnation composition, catalyst calcined with difference concentration of hydrochloric acid and calcined with difference hydrochloric acid ratio. After that, all of catalyst which have been prepared, used for steam reforming process for hydrogen production from glycerol as a raw material. From the study, the highest yield of hydrogen gas showed in the process production by natural zeolite catalyst with 1:15 Hydrochloric acid ratio was 42.28%. Hydrogen yield for 2M calcined natural zeolite catalyst was 38.37%, for ZSM-5 catalyst was 15.83%, for 0.5M calcined natural zeolite was 13.09% and for ultrasonic natural zeolite was 11.43%. The lowest yield of hydrogen gas showed in catalyst 2Zn/ZSM-5 with 11.22%. This result showed that hydrogen yield product was affected by catalyst variation because of the catalyst has difference characteristic and difference catalytic activity after the catalyst preparation process.

A methodology for thermodynamic simulation of high temperature, internal reforming fuel cell systems

NASA Astrophysics Data System (ADS)

Matelli, José Alexandre; Bazzo, Edson

This work presents a methodology for simulation of fuel cells to be used in power production in small on-site power/cogeneration plants that use natural gas as fuel. The methodology contemplates thermodynamics and electrochemical aspects related to molten carbonate and solid oxide fuel cells (MCFC and SOFC, respectively). Internal steam reforming of the natural gas hydrocarbons is considered for hydrogen production. From inputs as cell potential, cell power, number of cell in the stack, ancillary systems power consumption, reformed natural gas composition and hydrogen utilization factor, the simulation gives the natural gas consumption, anode and cathode stream gases temperature and composition, and thermodynamic, electrochemical and practical efficiencies. Both energetic and exergetic methods are considered for performance analysis. The results obtained from natural gas reforming thermodynamics simulation show that the hydrogen production is maximum around 700 °C, for a steam/carbon ratio equal to 3. As shown in the literature, the found results indicate that the SOFC is more efficient than MCFC.

Studying the characteristics of a 5 kW power installation on solid-oxide fuel cells with steam reforming of natural gas

NASA Astrophysics Data System (ADS)

Munts, V. A.; Volkova, Yu. V.; Plotnikov, N. S.; Dubinin, A. M.; Tuponogov, V. G.; Chernishev, V. A.

2015-11-01

The results from tests of a 5 kW power plant on solid-oxide fuel cells (SOFCs), in which natural gas is used as fuel, are presented. The installation's process circuit, the test procedure, and the analysis of the obtained results are described. The characteristics of the power plant developed by the Ural Industrial Company are investigated in four steady-state modes of its operation: with the SOFC nominal power capacity utilized by 40% (2 kW), 60% (3 kW), 90% (4.5 kW) and 110% (5.4 kW) (the peaking mode). The electrical and thermodynamic efficiencies are calculated for all operating modes, and the most efficient mode, in which the electrical efficiency reached almost 70%, is determined. The air excess coefficient and heat loss with flue gases q 2 are determined, and it is revealed that the heat loss q 5 decreases from 40 to 25% with increasing the load. Thermal balances are drawn up for the following components of the system the reformer, the SOFC battery, the catalytic burner for afterburning anode gases, the heat exchanger for heating the cathode air and the mixture of natural gas and steam, and the actual fuel utilization rates in the electrochemical generator are calculated. An equation for the resulting natural gas steam reforming reaction was obtained based on the results from calculating the equilibrium composition of reforming products for the achieved temperatures at the reformer outlet t 3.

One-Pot Synthesis of Mesoporous Ni-Ti-Al Ternary Oxides: Highly Active and Selective Catalysts for Steam Reforming of Ethanol.

PubMed

Gonçalves, Alexandre A S; Faustino, Patrícia B; Assaf, José M; Jaroniec, Mietek

2017-02-22

One-pot synthesis of nanostructured ternary oxides of Ni, Al, and Ti was designed and performed via evaporation induced self-assembly (EISA). For the purpose of comparison, analogous oxides were also prepared by the impregnation method. The resulting materials were applied in two catalytic reactions: steam reforming of ethanol (SRE) for H 2 production (subjected to prior activation with H 2 ) and ethanol dehydration (ED; used without prior activation), to in situ analyze carbon accumulation by ethylene depletion when ethanol interacts with acidic sites present on the support. Modification of Ni-Al mixed oxides with titania was shown to have several benefits. CO 2 , NH 3 , and propylamine sorption data indicate a decrease in the strength of acidic and basic sites after addition of titania, which in turn slowed down the carbon accumulation during the ED reaction. These changes in interactions between ethanol and byproducts with the support led to different reaction pathways in SRE, indicating that the catalysts obtained by EISA with titania addition showed higher ethylene selectivity and CO 2 /CO ratios. The opposite was observed for the impregnated catalysts, which were less coke-stable during ED reactions and showed no ethylene selectivity in SRE. Carbon formed during ED reactions was shown to be thermodynamically less favorable and easier to decompose in the presence of titania. All catalysts studied displayed similar and high selectivities (∼80%) and yields (∼5.3 mol H2 /mol ethanol ) toward H 2 , which place them among the most active and selective catalysts for SRE. These results indicate the importance of tailoring the support surface acidity to achieve high reforming performance and higher selectivity toward SRE, one of the key processes to produce cleaner and efficient fuels. For an efficient reforming process, the yield of byproducts is low but still they affect the catalyst stability in the long-run, thus this work may impact future studies toward

Modeling and 3D-simulation of hydrogen production via methanol steam reforming in copper-coated channels of a mini reformer

NASA Astrophysics Data System (ADS)

Sari, Ataallah; Sabziani, Javad

2017-06-01

Modeling and CFD simulation of a three-dimensional microreactor includes thirteen structured parallel channels is performed to study the hydrogen production via methanol steam reforming reaction over a Cu/ZnO/Al2O3 catalyst. The well-known Langmuir-Hinshelwood macro kinetic rate expressions reported by Peppley and coworkers [49] are considered to model the methanol steam reforming reactions. The effects of inlet steam to methanol ratio, pre-heat temperature, channels geometry and size, and the level of external heat flux on the hydrogen quality and quantity (i.e., hydrogen flow rate and CO concentration) are investigated. Moreover, the possibility of reducing the CO concentration by passing the reactor effluent through a water gas shift channel placed in series with the methanol reformer is studied. Afterwards, the simulation results are compared with the experimental data reported in the literature considering two different approaches of mixture-averaged and Maxwell-Stefan formulations to evaluate the diffusive flux of mass. The results indicate that the predictions of the Maxwell-Stefan model is in better agreement with experimental data than mixture-averaged one, especially at the lower feed flow rates.

A numerical analysis of heat and mass transfer during the steam reforming process of ethane

NASA Astrophysics Data System (ADS)

Tomiczek, Marcin; Kaczmarczyk, Robert; Mozdzierz, Marcin; Brus, Grzegorz

2017-11-01

This paper presents a numerical analysis of heat and mass transfer during the steam reforming of ethane. From a chemical point of view, the reforming process of heavy hydrocarbons, such as ethane, is complex. One of the main issue is a set of undesired chemical reactions that causes the deposition of solid carbon and consequently blocks the catalytic property of a reactor. In the literature a carbon deposition regime is selected by thermodynamical analysis to design safe operation conditions. In the case of Computational Fluid Dynamic (CFD, hereafter) models each control volume should be investigated to determinate if carbon deposition is thermodynamically favourable. In this paper the authors combine equilibrium and kinetics analysis to simulate the steam reforming of methane-ethane rich fuel. The results of the computations were juxtaposed with experimental data for methane steam reforming, and good agreement was found. An analysis based on the kinetics of reactions was conducted to predict the influence of temperature drop and non-equilibrium composition on solid carbon deposition. It was found that strong non-uniform temperature distribution in the reactor causes conditions favourable for carbon deposition at the inlet of the reformer. It was shown that equilibrium calculations, often used in the literature, are insufficient.

Efficiency of a hybrid-type plasma-assisted fuel reformation system

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

Matveev, I.B.; Serbin, S.I.; Lux, S.M.

2008-12-15

The major advantages of a new plasma-assisted fuel reformation system are its cost effectiveness and technical efficiency. Applied Plasma Technologies has proposed its new highly efficient hybrid-type plasma-assisted system for organic fuel combustion and gasification. The system operates as a multimode multipurpose reactor in a wide range of plasma feedstock gases and turndown ratios. This system also has convenient and simultaneous feeding of several reagents in the reaction zone such as liquid fuels, coal, steam, and air. A special methodology has been developed for such a system in terms of heat balance evaluation and optimization. This methodology considers all existingmore » and possible energy streams, which could influence the system's efficiency. The developed hybrid-type plasma system could be suitable for combustion applications, mobile and autonomous small- to mid-size liquid fuel and coal gasification modules, hydrogen-rich gas generators, waste-processing facilities, and plasma chemical reactors.« less

Modified Ni-Cu catalysts for ethanol steam reforming

NASA Astrophysics Data System (ADS)

Dan, M.; Mihet, M.; Almasan, V.; Borodi, G.; Katona, G.; Muresan, L.; Lazar, M. D.

2013-11-01

Three Ni-Cu catalysts, having different Cu content, supported on γ-alumina were synthesized by wet co-impregnation method, characterized and tested in the ethanol steam reforming (ESR) reaction. The catalysts were characterized for determination of: total surface area and porosity (N2 adsorption - desorption using BET and Dollimer Heal methods), Ni surface area (hydrogen chemisorption), crystallinity and Ni crystallites size (X-Ray Diffraction), type of catalytic active centers (Hydrogen Temperature Programmed Reduction). Total surface area and Ni crystallites size are not significantly influenced by the addition of Cu, while Ni surface area is drastically diminished by increasing of Cu concentration. Steam reforming experiments were performed at atmospheric pressure, temperature range 150-350°C, and ethanol - water molar ration of 1 at 30, using Ar as carrier gas. Ethanol conversion and hydrogen production increase by the addition of Cu. At 350°C there is a direct connection between hydrogen production and Cu concentration. Catalysts deactivation in 24h time on stream was studied by Transmission Electron Microscopy (TEM) and temperature-programmed reduction (TPR) on used catalysts. Coke deposition was observed at all studied temperatures; at 150°C amorphous carbon was evidenced, while at 350°C crystalline, filamentous carbon is formed.

Comparison of partial oxidation and steam-CO{sub 2} mixed reforming of CH{sub 4} to syngas on MgO-supported metals

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

Qin, D.; Lapszewicz, J.; Jiang, X.

1996-03-01

Partial oxidation (POX) and steam-CO{sub 2} mixed reforming of CH{sub 4} on MgO-supported noble metals were investigated at high space velocity (5.5 x 10{sup 5} h{sup -1}). Temperature-programmed reaction (TPR) and isotope transient techniques were used to study the mechanism of POX and mixed reforming. TPR profiles of POX and mixed reforming showed similar ignition reaction behaviors, which implied that there are similar characteristics in their mechanisms. Steam reforming and CO{sub 2} reforming were found to start at the same time in mixed reforming. TPR and CH{sub 4}-D{sub 2} exchange experiments indicated that CH{sub 4} was activated at low temperaturemore » on Rh/MgO. POX showed much higher activity than mixed reforming although their C, H, and O atomic concentrations were the same at the beginning of each reaction. Mechanisms for POX and mixed reforming are suggested and the effect of oxygen-metal bond strength on activity is discussed. 31 refs., 11 figs., 3 tabs.« less

Process Evaluation - Steam Reforming of Diesel Fuel Oil

DTIC Science & Technology

1980-02-15

Table 9. HIDROGEN CONVERSION RELATIVE TO TEMPERATURE, SPACE, VELOCITY, AND H20/C RATIO Oil Feed, Gas Product ,Run No. Temperature, *F H2,O/C Ratio igram...steam reforming diesel fuel, but with the production of naphthalene after 30 hours. Hydrogen production remained stable through the 86 hours of the test...79-C-0048. Hydrogen-rich gas was produced over a wide range of reaction conditions. This product gas contained small amounts of ethylene and !nzene

Self-assembly of highly efficient, broadband plasmonic absorbers for solar steam generation

PubMed Central

Zhou, Lin; Tan, Yingling; Ji, Dengxin; Zhu, Bin; Zhang, Pei; Xu, Jun; Gan, Qiaoqiang; Yu, Zongfu; Zhu, Jia

2016-01-01

The study of ideal absorbers, which can efficiently absorb light over a broad range of wavelengths, is of fundamental importance, as well as critical for many applications from solar steam generation and thermophotovoltaics to light/thermal detectors. As a result of recent advances in plasmonics, plasmonic absorbers have attracted a lot of attention. However, the performance and scalability of these absorbers, predominantly fabricated by the top-down approach, need to be further improved to enable widespread applications. We report a plasmonic absorber which can enable an average measured absorbance of ~99% across the wavelengths from 400 nm to 10 μm, the most efficient and broadband plasmonic absorber reported to date. The absorber is fabricated through self-assembly of metallic nanoparticles onto a nanoporous template by a one-step deposition process. Because of its efficient light absorption, strong field enhancement, and porous structures, which together enable not only efficient solar absorption but also significant local heating and continuous stream flow, plasmonic absorber–based solar steam generation has over 90% efficiency under solar irradiation of only 4-sun intensity (4 kW m−2). The pronounced light absorption effect coupled with the high-throughput self-assembly process could lead toward large-scale manufacturing of other nanophotonic structures and devices. PMID:27152335

Self-assembly of highly efficient, broadband plasmonic absorbers for solar steam generation.

PubMed

Zhou, Lin; Tan, Yingling; Ji, Dengxin; Zhu, Bin; Zhang, Pei; Xu, Jun; Gan, Qiaoqiang; Yu, Zongfu; Zhu, Jia

2016-04-01

The study of ideal absorbers, which can efficiently absorb light over a broad range of wavelengths, is of fundamental importance, as well as critical for many applications from solar steam generation and thermophotovoltaics to light/thermal detectors. As a result of recent advances in plasmonics, plasmonic absorbers have attracted a lot of attention. However, the performance and scalability of these absorbers, predominantly fabricated by the top-down approach, need to be further improved to enable widespread applications. We report a plasmonic absorber which can enable an average measured absorbance of ~99% across the wavelengths from 400 nm to 10 μm, the most efficient and broadband plasmonic absorber reported to date. The absorber is fabricated through self-assembly of metallic nanoparticles onto a nanoporous template by a one-step deposition process. Because of its efficient light absorption, strong field enhancement, and porous structures, which together enable not only efficient solar absorption but also significant local heating and continuous stream flow, plasmonic absorber-based solar steam generation has over 90% efficiency under solar irradiation of only 4-sun intensity (4 kW m(-2)). The pronounced light absorption effect coupled with the high-throughput self-assembly process could lead toward large-scale manufacturing of other nanophotonic structures and devices.

Activity Tests of Macro-Meso Porous Catalysts over Metal Foam Plate for Steam Reforming of Bio-Ethanol.

PubMed

Park, No-Kuk; Jeong, Yong Han; Kang, Misook; Lee, Tae Jin

2018-09-01

The catalytic activity of a macro-mesoporous catalyst coated on a metal foam plate in the reforming of bio-ethanol to synthesis gas was investigated. The catalysts were prepared by coating a support with a noble metal and transition metal. The catalytic activity for the production of synthetic gas by the reforming of bio-ethanol was compared according to the support material, reaction temperature, and steam/carbon ratio. The catalysts coated on the metal foams were prepared using a template method, in which macro-pores and meso-pores were formed by mixing polymer beads. In particular, the thermodynamic equilibrium composition of bio-ethanol reforming with the reaction temperature and steam/carbon ratio to produce synthetic gas was examined using the HSC (Enthalpy-Entropy-Heat capacity) chemistry program in this study. The composition of hydrogen and carbon monoxide in the reformate gas produced by steam reforming over the Rh/Ni-Ce-Zr/Al2O3-based pellet type catalysts and metal foam catalysts that had been coated with the Rh/Al-Ce-Zr-based catalysts was investigated by experimental activity tests. The activity of the metal foam catalyst was higher than that of the pellet type catalyst.

Thermodynamic evaluation of hydrogen production for fuel cells by using bio-ethanol steam reforming: Effect of carrier gas addition

NASA Astrophysics Data System (ADS)

Hernández, Liliana; Kafarov, Viatcheslav

Omitting the influence of the addition of carrier gas to the reaction system for hydrogen production by bio-ethanol steam reforming can lead to wrong conclusions, especially when it is going to be made to scale. The effect of carrier gas addition to produce hydrogen using bio-ethanol steam reforming to feed fuel cells was evaluated. Thermodynamic calculations in equilibrium conditions were made, however the analysis derived from them can also be applied to kinetic conditions. These calculations were made by using the Aspen-HYSYS software at atmospheric pressure and different values of temperature, water/ethanol molar ratios, and inert (argon)/(water/ethanol) molar ratios. The addition of inert carrier gas modifies the concentrations of the reaction products in comparison to those obtained without its presence. This behavior occurs because most of the reactions which take place in bio-ethanol steam reforming have a positive difference of moles. This fact enhances the system sensitivity to inert concentration at low and moderated temperatures (<700 °C). At high values of temperature, the inert addition does not influence the composition of the reaction products because of the predominant effect of inverse WGS reaction.

CATALYTIC STEAM REFORMING OF CHLOROCARBONS: POLYCHLORINATED BIPHENYLS (PCBS). (R826694C633)

EPA Science Inventory

Experiments with commercial askarals (Aroclors 1221, 1248 and 1254) have confirmed the feasibility of catalytic steam reforming as a method for destroying polychlorinated biphenyls (PCBs). Rhodium, platinum and nickel supported on CATALYTIC STEAM REFORMING OF CHLOROCARBONS: CATALYST DEACTIVATION. (R826694C633)

EPA Science Inventory

Deactivation of 0.5 wt.% Pt/-Al₂O₃ catalysts during trichloroethylene (TCE)–steam reforming was studied with experiments at 700°C, H

Heat and fuel coupled operation of a high temperature polymer electrolyte fuel cell with a heat exchanger methanol steam reformer

NASA Astrophysics Data System (ADS)

Schuller, G.; Vázquez, F. Vidal; Waiblinger, W.; Auvinen, S.; Ribeirinha, P.

2017-04-01

In this work a methanol steam reforming (MSR) reactor has been operated thermally coupled to a high temperature polymer electrolyte fuel cell stack (HT-PEMFC) utilizing its waste heat. The operating temperature of the coupled system was 180 °C which is significantly lower than the conventional operating temperature of the MSR process which is around 250 °C. A newly designed heat exchanger reformer has been developed by VTT (Technical Research Center of Finland LTD) and was equipped with commercially available CuO/ZnO/Al2O3 (BASF RP-60) catalyst. The liquid cooled, 165 cm2, 12-cell stack used for the measurements was supplied by Serenergy A/S. The off-heat from the electrochemical fuel cell reaction was transferred to the reforming reactor using triethylene glycol (TEG) as heat transfer fluid. The system was operated up to 0.4 A cm-2 generating an electrical power output of 427 Wel. A total stack waste heat utilization of 86.4% was achieved. It has been shown that it is possible to transfer sufficient heat from the fuel cell stack to the liquid circuit in order to provide the needed amount for vaporizing and reforming of the methanol-water-mixture. Furthermore a set of recommendations is given for future system design considerations.

STEAM REFORMING OF CHLOROCARBONS: CHLORINATED AROMATICS. (R826694C633)

EPA Science Inventory

Effective dechlorination of chloroaromatics, such as C₆H₅Cl, 1,2-C₆H₄Cl₂, 1,3-C₆H₄Cl₂ and 1,2,4-C₆H₃Cl₃, using catalytic steam reforming has been confirmed ...

Performance and economic assessments of a solid oxide fuel cell system with a two-step ethanol-steam-reforming process using CaO sorbent

NASA Astrophysics Data System (ADS)

Tippawan, Phanicha; Arpornwichanop, Amornchai

2016-02-01

The hydrogen production process is known to be important to a fuel cell system. In this study, a carbon-free hydrogen production process is proposed by using a two-step ethanol-steam-reforming procedure, which consists of ethanol dehydrogenation and steam reforming, as a fuel processor in the solid oxide fuel cell (SOFC) system. An addition of CaO in the reformer for CO2 capture is also considered to enhance the hydrogen production. The performance of the SOFC system is analyzed under thermally self-sufficient conditions in terms of the technical and economic aspects. The simulation results show that the two-step reforming process can be run in the operating window without carbon formation. The addition of CaO in the steam reformer, which runs at a steam-to-ethanol ratio of 5, temperature of 900 K and atmospheric pressure, minimizes the presence of CO2; 93% CO2 is removed from the steam-reforming environment. This factor causes an increase in the SOFC power density of 6.62%. Although the economic analysis shows that the proposed fuel processor provides a higher capital cost, it offers a reducing active area of the SOFC stack and the most favorable process economics in term of net cost saving.

CATALYTIC STEAM REFORMING OF CHLOROCARBONS: CATALYST COMPARISONS. (R826694C633)

EPA Science Inventory

Catalyst candidates for steam reforming chlorocarbons have been screened for activity using methyl chloride as a model reactant. At 500°C, a H₂O/C ratio of about 10 and a GHSV of 254 000 h^-1, catalysts comprising 0.5% loading of the metals ...

CATALYTIC STEAM REFORMING OF CHLOROCARBONS: CATALYST COMPARISONS. (R822721C633)

EPA Science Inventory

Catalyst candidates for steam reforming chlorocarbons have been screened for activity using methyl chloride as a model reactant. At 500°C, a H₂O/C ratio of about 10 and a GHSV of 254 000 h^-1, catalysts comprising 0.5% loading of the metals o...

Methods of increasing thermal efficiency of steam and gas turbine plants

NASA Astrophysics Data System (ADS)

Vasserman, A. A.; Shutenko, M. A.

2017-11-01

Three new methods of increasing efficiency of turbine power plants are described. Increasing average temperature of heat supply in steam turbine plant by mixing steam after overheaters with products of combustion of natural gas in the oxygen. Development of this idea consists in maintaining steam temperature on the major part of expansion in the turbine at level, close to initial temperature. Increasing efficiency of gas turbine plant by way of regenerative heating of the air by gas after its expansion in high pressure turbine and before expansion in the low pressure turbine. Due to this temperature of air, entering combustion chamber, is increased and average temperature of heat supply is consequently increased. At the same time average temperature of heat removal is decreased. Increasing efficiency of combined cycle power plant by avoiding of heat transfer from gas to wet steam and transferring heat from gas to water and superheated steam only. Steam will be generated by multi stage throttling of the water from supercritical pressure and temperature close to critical, to the pressure slightly higher than condensation pressure. Throttling of the water and separation of the wet steam on saturated water and steam does not require complicated technical devices.

CATALYTIC STEAM REFORMING OF CHLOROCARBONS: TRICHLOROETHANE, TRICHLOROETHYLENE AND PERCHLOROETHYLENE. (R826694C633)

EPA Science Inventory

The effective destruction of trichloroethane, trichloroethylene and perchloroethylene by steam reforming with a commercial nickel catalyst has been demonstrated. Conversion levels of up to 0.99999 were attained in both laboratory and semi-pilot experiments, with the products c...

Reforming options for hydrogen production from fossil fuels for PEM fuel cells

NASA Astrophysics Data System (ADS)

Ersoz, Atilla; Olgun, Hayati; Ozdogan, Sibel

PEM fuel cell systems are considered as a sustainable option for the future transport sector in the future. There is great interest in converting current hydrocarbon based transportation fuels into hydrogen rich gases acceptable by PEM fuel cells on-board of vehicles. In this paper, we compare the results of our simulation studies for 100 kW PEM fuel cell systems utilizing three different major reforming technologies, namely steam reforming (SREF), partial oxidation (POX) and autothermal reforming (ATR). Natural gas, gasoline and diesel are the selected hydrocarbon fuels. It is desired to investigate the effect of the selected fuel reforming options on the overall fuel cell system efficiency, which depends on the fuel processing, PEM fuel cell and auxiliary system efficiencies. The Aspen-HYSYS 3.1 code has been used for simulation purposes. Process parameters of fuel preparation steps have been determined considering the limitations set by the catalysts and hydrocarbons involved. Results indicate that fuel properties, fuel processing system and its operation parameters, and PEM fuel cell characteristics all affect the overall system efficiencies. Steam reforming appears as the most efficient fuel preparation option for all investigated fuels. Natural gas with steam reforming shows the highest fuel cell system efficiency. Good heat integration within the fuel cell system is absolutely necessary to achieve acceptable overall system efficiencies.

Coupling of a 2.5 kW steam reformer with a 1 kW el PEM fuel cell

NASA Astrophysics Data System (ADS)

Mathiak, J.; Heinzel, A.; Roes, J.; Kalk, Th.; Kraus, H.; Brandt, H.

The University of Duisburg-Essen has developed a compact multi-fuel steam reformer suitable for natural gas, propane and butane. This steam reformer was combined with a polymer electrolyte membrane fuel cell (PEM FC) and a system test of the process chain was performed. The fuel processor comprises a prereformer step, a primary reformer, water gas shift reactors, a steam generator, internal heat exchangers in order to achieve an optimised heat integration and an external burner for heat supply as well as a preferential oxidation step (PROX) as CO purification. The fuel processor is designed to deliver a thermal hydrogen power output from 500 W to 2.5 kW. The PEM fuel cell stack provides about 1 kW electrical power. In the following paper experimental results of measurements of the single components PEM fuel cell and fuel processor as well as results of the coupling of both to form a process chain are presented.

Multifunctional Porous Graphene for High-Efficiency Steam Generation by Heat Localization.

PubMed

Ito, Yoshikazu; Tanabe, Yoichi; Han, Jiuhui; Fujita, Takeshi; Tanigaki, Katsumi; Chen, Mingwei

2015-08-05

Multifunctional nanoporous graphene is realized as a heat generator to convert solar illumination into high-energy steam. The novel 3D nanoporous graphene demonstrates a highly energy-effective steam generation with an energy conversation of 80%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Processing real-world waste plastics by pyrolysis-reforming for hydrogen and high-value carbon nanotubes.

PubMed

Wu, Chunfei; Nahil, Mohamad A; Miskolczi, Norbert; Huang, Jun; Williams, Paul T

2014-01-01

Producing both hydrogen and high-value carbon nanotubes (CNTs) derived from waste plastics is reported here using a pyrolysis-reforming technology comprising a two-stage reaction system, in the presence of steam and a Ni-Mn-Al catalyst. The waste plastics consisted of plastics from a motor oil container (MOC), commercial waste high density polyethylene (HDPE) and regranulated HDPE waste containing polyvinyl chloride (PVC). The results show that hydrogen can be produced from the pyrolysis-reforming process, but also carbon nanotubes are formed on the catalyst. However, the content of 0.3 wt.% polyvinyl chloride in the waste HDPE (HDPE/PVC) has been shown to poison the catalyst and significantly reduce the quantity and purity of CNTs. The presence of sulfur has shown less influence on the production of CNTs in terms of quantity and CNT morphologies. Around 94.4 mmol H2 g(-1) plastic was obtained for the pyrolysis-reforming of HDPE waste in the presence of the Ni-Mn-Al catalyst and steam at a reforming temperature of 800 °C. The addition of steam in the process results in an increase of hydrogen production and reduction of carbon yield; in addition, the defects of CNTs, for example, edge dislocations were found to be increased with the introduction of steam (from Raman analysis).

Metallic phases of cobalt-based catalysts in ethanol steam reforming: The effect of cerium oxide

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

Lin, Sean S.-Y.; Kim, Do Heui; Ha, Su Y.

2009-02-28

The catalytic activity of cobalt in the production of hydrogen via ethanol steam reforming has been investigated in its relation to the crystalline structure of metallic cobalt. At a reaction temperature of 350 8C, the specific hydrogen production rates show that hexagonal close-packed (hcp) cobalt possesses higher activity than face-centered cubic (fcc) cobalt. However, at typical reaction temperatures (400– 500 8C) for ethanol steam reforming, hcp cobalt is transformed to less active fcc cobalt, as confirmed by in situ X-ray diffractometry (XRD). The addition of CeO2 promoter (10 wt.%) stabilizes the hcp cobalt structure at reforming temperatures up to 600more » 8C. Moreover, during the pre-reduction process, CeO2 promoter prevents sintering during the transformation of Co3O4 to hcp cobalt. Both reforming experiments and in situ diffuse-reflectance infrared Fourier transform spectroscopy (DRIFTS) showed that the surface reactions were modified by CeO2 promoter on 10% Ce–Co (hcp) to give a lower CO selectivity and a higher H2 yield as compared with the unpromoted hcp Co.« less

Fluidized bed steam reformed mineral waste form performance testing to support Hanford Supplemental Low Activity Waste Immobilization Technology Selection

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

Jantzen, C. M.; Pierce, E. M.; Bannochie, C. J.

This report describes the benchscale testing with simulant and radioactive Hanford Tank Blends, mineral product characterization and testing, and monolith testing and characterization. These projects were funded by DOE EM-31 Technology Development & Deployment (TDD) Program Technical Task Plan WP-5.2.1-2010-001 and are entitled “Fluidized Bed Steam Reformer Low-Level Waste Form Qualification”, Inter-Entity Work Order (IEWO) M0SRV00054 with Washington River Protection Solutions (WRPS) entitled “Fluidized Bed Steam Reforming Treatability Studies Using Savannah River Site (SRS) Low Activity Waste and Hanford Low Activity Waste Tank Samples”, and IEWO M0SRV00080, “Fluidized Bed Steam Reforming Waste Form Qualification Testing Using SRS Low Activity Wastemore » and Hanford Low Activity Waste Tank Samples”. This was a multi-organizational program that included Savannah River National Laboratory (SRNL), THOR® Treatment Technologies (TTT), Pacific Northwest National Laboratory (PNNL), Oak Ridge National Laboratory (ORNL), Office of River Protection (ORP), and Washington River Protection Solutions (WRPS). The SRNL testing of the non-radioactive pilot-scale Fluidized Bed Steam Reformer (FBSR) products made by TTT, subsequent SRNL monolith formulation and testing and studies of these products, and SRNL Waste Treatment Plant Secondary Waste (WTP-SW) radioactive campaign were funded by DOE Advanced Remediation Technologies (ART) Phase 2 Project in connection with a Work-For-Others (WFO) between SRNL and TTT.« less

Pyrolysis of de-oiled seed cake of Jatropha Curcas and catalytic steam reforming of pyrolytic bio-oil to hydrogen.

PubMed

Renny, Andrew; Santhosh, Viswanathan; Somkuwar, Nitin; Gokak, D T; Sharma, Pankaj; Bhargava, Sanjay

2016-11-01

The aim of this work was to study the pyrolysis of de-oiled seed cake of Jatropha Curcas and catalytic steam reforming of pyrolytic bio-oil to hydrogen. As per literature, presence of heavy nitrogenous and oxygenated compounds leads to catalyst deactivation. Here, an attempt has been made to tune pyrolytic reactions to optimize the N and O content of the pyrolytic bio-oil. Bio-oil conversion and hydrogen yield decreased as reaction progressed, which attributes to temporary loss of catalytic activity by blockage of catalyst pores by carbon deposition. Further, retention of steam reforming activity after repetitive steam activation suggests long-term catalyst usage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of Technologies on Innovative-Simplified Nuclear Power Plant using High-Efficiency Steam Injectors

NASA Astrophysics Data System (ADS)

Ohmori, Shuichi; Narabayashi, Tadashi; Mori, Michitsugu; Iwaki, Chikako; Asanuma, Yutaka; Goto, Shoji

A Steam Injector (SI) is a simple, compact and passive pump and also acts as a high-performance direct-contact heater. This provides SI with capability to serve also as a direct-contact feed-water heater that heats up feed-water by using extracted steam from turbine. Our technology development aims to significantly simplify equipment and reduce physical quantities by applying "High-Efficiency SI", which are applicable to a wide range of operation regimes beyond the performance and applicable range of existing SIs and enables unprecedented multistage and parallel operation, to the low-pressure feed-water heaters and Emergency Core Cooling System of nuclear power plants, as well as achieve high inherent safety to prevent severe accidents by keeping the core covered with water (a Severe Accident-Free Concept). This paper describes the results of the endurance and performance tests of low-pressure SIs for feed-water heaters with Jet-deaerator and core injection system.

Thermodynamic equilibrium calculations of hydrogen production from the combined processes of dimethyl ether steam reforming and partial oxidation

NASA Astrophysics Data System (ADS)

Semelsberger, Troy A.; Borup, Rodney L.

Thermodynamic analyses of producing a hydrogen-rich fuel-cell feed from the combined processes of dimethyl ether (DME) partial oxidation and steam reforming were investigated as a function of oxygen-to-carbon ratio (0.00-2.80), steam-to-carbon ratio (0.00-4.00), temperature (100 °C-600 °C), pressure (1-5 atm) and product species. Thermodynamically, dimethyl ether processed with air and steam generates hydrogen-rich fuel-cell feeds; however, the hydrogen concentration is less than that for pure DME steam reforming. Results of the thermodynamic processing of dimethyl ether indicate the complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide for temperatures greater than 200 °C, oxygen-to-carbon ratios greater than 0.00 and steam-to-carbon ratios greater than 1.25 at atmospheric pressure (P = 1 atm). Increasing the operating pressure has negligible effects on the hydrogen content. Thermodynamically, dimethyl ether can produce concentrations of hydrogen and carbon monoxide of 52% and 2.2%, respectively, at a temperature of 300 °C, and oxygen-to-carbon ratio of 0.40, a pressure of 1 atm and a steam-to-carbon ratio of 1.50. The order of thermodynamically stable products (excluding H 2, CO, CO 2, DME, NH 3 and H 2O) in decreasing mole fraction is methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol and methyl-ethyl ether; trace amounts of formaldehyde, formic acid and methanol are observed. Ammonia and hydrogen cyanide are also thermodynamically favored products. Ammonia is favored at low temperatures in the range of oxygen-to-carbon ratios of 0.40-2.50 regardless of the steam-to-carbon ratio employed. The maximum ammonia content (i.e., 40%) occurs at an oxygen-to-carbon ratio of 0.40, a steam-to-carbon ratio of 1.00 and a temperature of 100 °C. Hydrogen cyanide is favored at high temperatures and low oxygen-to-carbon ratios with a maximum of 3.18% occurring at an oxygen-to-carbon ratio of 0.40 and a steam

Thermodynamic analysis of the efficiency of high-temperature steam electrolysis system for hydrogen production

NASA Astrophysics Data System (ADS)

Mingyi, Liu; Bo, Yu; Jingming, Xu; Jing, Chen

High-temperature steam electrolysis (HTSE), a reversible process of solid oxide fuel cell (SOFC) in principle, is a promising method for highly efficient large-scale hydrogen production. In our study, the overall efficiency of the HTSE system was calculated through electrochemical and thermodynamic analysis. A thermodynamic model in regards to the efficiency of the HTSE system was established and the quantitative effects of three key parameters, electrical efficiency (η el), electrolysis efficiency (η es), and thermal efficiency (η th) on the overall efficiency (η overall) of the HTSE system were investigated. Results showed that the contribution of η el, η es, η th to the overall efficiency were about 70%, 22%, and 8%, respectively. As temperatures increased from 500 °C to 1000 °C, the effect of η el on η overall decreased gradually and the η es effect remained almost constant, while the η th effect increased gradually. The overall efficiency of the high-temperature gas-cooled reactor (HTGR) coupled with the HTSE system under different conditions was also calculated. With the increase of electrical, electrolysis, and thermal efficiency, the overall efficiencies were anticipated to increase from 33% to a maximum of 59% at 1000 °C, which is over two times higher than that of the conventional alkaline water electrolysis.

DATA QUALITY OBJECTIVES FOR SELECTING WASTE SAMPLES FOR BENCH-SCALE REFORMER TREATABILITY STUDIES

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

BANNING DL

2011-02-11

This document describes the data quality objectives to select archived samples located at the 222-S Laboratory for Bench-Scale Reforming testing. The type, quantity, and quality of the data required to select the samples for Fluid Bed Steam Reformer testing are discussed. In order to maximize the efficiency and minimize the time to treat Hanford tank waste in the Waste Treatment and Immobilization Plant, additional treatment processes may be required. One of the potential treatment processes is the fluidized bed steam reformer. A determination of the adequacy of the fluidized bed steam reformer process to treat Hanford tank waste is required.more » The initial step in determining the adequacy of the fluidized bed steam reformer process is to select archived waste samples from the 222-S Laboratory that will be used in a bench scale tests. Analyses of the selected samples will be required to confirm the samples meet the shipping requirements and for comparison to the bench scale reformer (BSR) test sample selection requirements.« less

Commercially Available Activated Carbon Fiber Felt Enables Efficient Solar Steam Generation.

PubMed

Li, Haoran; He, Yurong; Hu, Yanwei; Wang, Xinzhi

2018-03-21

Sun-driven steam generation is now possible and has the potential to help meet future energy needs. Current technologies often use solar condensers to increase solar irradiance. More recently, a technology for solar steam generation that uses heated surface water and low optical concentration is reported. In this work, a commercially available activated carbon fiber felt is used to generate steam efficiently under one sun illumination. The evaporation rate and solar conversion efficiency reach 1.22 kg m -2 h -1 and 79.4%, respectively. The local temperature of the evaporator with a floating activated carbon fiber felt reaches 48 °C. Apart from the high absorptivity (about 94%) of the material, the evaporation performance is enhanced thanks to the well-developed pores for improved water supply and steam escape and the low thermal conductivity, which enables reduced bulk water temperature increase. This study helps to find a promising material for solar steam generation using a water evaporator that can be produced economically (∼6 $/m 2 ) with long-term stability.

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.

CESIUM REMOVAL FROM TANKS 241-AN-103 & 241-SX-105 & 241-AZ-101/102 COMPOSITE FOR TESTING IN BENCH SCALE STEAM REFORMER

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

DUNCAN JB; HUBER HJ

2011-06-08

This report documents the preparation of three actual Hanford tank waste samples for shipment to the Savannah River National Laboratory (SRNL). Two of the samples were dissolved saltcakes from tank 241-AN-103 (hereafter AN-103) and tank 241-SX-105 (hereafter SX-105); one sample was a supernate composite from tanks 241-AZ-101 and 241-AZ-102 (hereafter AZ-101/102). The preparation of the samples was executed following the test plans LAB-PLAN-10-00006, Test Plan for the Preparation of Samples from Hanford Tanks 241-SX-105, 241-AN-103, 241-AN-107, and LAB-PLN-10-00014, Test Plan for the Preparation of a Composite Sample from Hanford Tanks 241-AZ-101 and 241-AZ-102 for Steam Reformer Testing at the Savannahmore » River National Laboratory. All procedural steps were recorded in laboratory notebook HNF-N-274 3. Sample breakdown diagrams for AN-103 and SX-105 are presented in Appendix A. The tank samples were prepared in support of a series of treatability studies of the Fluidized Bed Steam Reforming (FBSR) process using a Bench-Scale Reformer (BSR) at SRNL. Tests with simulants have shown that the FBSR mineralized waste form is comparable to low-activity waste glass with respect to environmental durability (WSRC-STI-2008-00268, Mineralization of Radioactive Wastes by Fluidized Bed Steam Reforming (FBSR): Comparisons to Vitreous Waste Forms and Pertinent Durability Testing). However, a rigorous assessment requires long-term performance data from FB SR product formed from actual Hanford tank waste. Washington River Protection Solutions, LLC (WRPS) has initiated a Waste Form Qualification Program (WP-S.2.1-20 1 0-00 1, Fluidized Bed Steam Reformer Low-level Waste Form Qualification) to gather the data required to demonstrate that an adequate FBSR mineralized waste form can be produced. The documentation of the selection process of the three tank samples has been separately reported in RPP-48824, 'Sample Selection Process for Bench-Scale Steam Reforming Treatability Studies

Superior performance of Ni–W–Ce mixed-metal oxide catalysts for ethanol steam reforming: Synergistic effects of W- and Ni-dopants

DOE PAGES

Liu, Zongyuan; Xu, Wenqian; Yao, Siyu; ...

2014-11-26

In this study, the ethanol steam reforming (ESR) reaction was examined over a series of Ni-W-Ce oxide catalysts. The structures of the catalysts were characterized using in-situ techniques including X-ray diffraction, Pair Distribution Function, X-ray absorption fine structure and transmission electron microscopy; while possible surface intermediates for the ESR reaction were investigated by Diffuse Reflectance Infrared Fourier Transform Spectroscopy. In these materials, all the W and part of the Ni were incorporated into the CeO₂ lattice, with the remaining Ni forming highly dispersed nano NiO (< 2 nm) outside the Ni-W-Ce oxide structure. The nano NiO was reduced to Nimore » under ESR conditions. The Ni-W-Ce systeme exhibited a much larger lattice strain than those seen for Ni-Ce and W-Ce. Synergistic effects between Ni and W inside ceria produced a substantial amount of defects and O vacancies that led to high catalytic activity, selectivity and stability (i.e. resistance to coke formation) during ethanol steam reforming.« less

Bi-reforming of methane from any source with steam and carbon dioxide exclusively to metgas (CO-2H2) for methanol and hydrocarbon synthesis.

PubMed

Olah, George A; Goeppert, Alain; Czaun, Miklos; Prakash, G K Surya

2013-01-16

A catalyst based on nickel oxide on magnesium oxide (NiO/MgO) thermally activated under hydrogen is effective for the bi-reforming with steam and CO(2) (combined steam and dry reforming) of methane as well as natural gas in a tubular flow reactor at elevated pressures (5-30 atm) and temperatures (800-950 °C). By adjusting the CO(2)-to-steam ratio in the gas feed, the H(2)/CO ratio in the produced syn-gas could be easily adjusted in a single step to the desired value of 2 for methanol and hydrocarbon synthesis.

Steam reforming of simulated bio-oil on K-Ni-Cu-Mg-Ce-O/Al 2O 3: The effect of K

DOE PAGES

Yu, Ning; Rahman, Muhammad Mahfuzur; Chen, Jixiang; ...

2018-04-10

Steam reforming of simulated bio-oil (ethanol, acetone, phenol, and acetic acid) and phenol has been studied on K-Ni-Cu-Mg-Ce-O/Al 2O 3 composite catalysts. Complementary characterization techniques, such as nitrogen sorption, XRD, H 2-TPR, H 2-TPD, CO-TPD, CO-DRIFTS, and in situ XPS, were used to correlate surface structure and functionality to catalytic performance of potassium (K) doped catalysts. K doping of the Ni-Cu-Mg-Ce-O/Al 2O 3 catalyst created a Ni°/Ni 2+ mixed active phase, which not only enhanced steam reforming activity, but also suppressed the methanation reaction. In addition, K doping changed the surface acid-basic properties of the catalyst, which instead favor themore » gasifcation and water-gas shift reactions. In conclusion, with the combination of these effects, K doping of Ni-Cu-Mg-Ce-O/Al 2O 3 catalysts led to higher C1 yield and much lower methane formation, favoring hydrogen production in steam reforming of both phenol and simulated bio-oil.« less

Steam reforming of simulated bio-oil on K-Ni-Cu-Mg-Ce-O/Al 2O 3: The effect of K

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

Yu, Ning; Rahman, Muhammad Mahfuzur; Chen, Jixiang

Steam reforming of simulated bio-oil (ethanol, acetone, phenol, and acetic acid) and phenol has been studied on K-Ni-Cu-Mg-Ce-O/Al 2O 3 composite catalysts. Complementary characterization techniques, such as nitrogen sorption, XRD, H 2-TPR, H 2-TPD, CO-TPD, CO-DRIFTS, and in situ XPS, were used to correlate surface structure and functionality to catalytic performance of potassium (K) doped catalysts. K doping of the Ni-Cu-Mg-Ce-O/Al 2O 3 catalyst created a Ni°/Ni 2+ mixed active phase, which not only enhanced steam reforming activity, but also suppressed the methanation reaction. In addition, K doping changed the surface acid-basic properties of the catalyst, which instead favor themore » gasifcation and water-gas shift reactions. In conclusion, with the combination of these effects, K doping of Ni-Cu-Mg-Ce-O/Al 2O 3 catalysts led to higher C1 yield and much lower methane formation, favoring hydrogen production in steam reforming of both phenol and simulated bio-oil.« less

Thermochemically recuperated and steam cooled gas turbine system

DOEpatents

Viscovich, Paul W.; Bannister, Ronald L.

1995-01-01

A gas turbine system in which the expanded gas from the turbine section is used to generate the steam in a heat recovery steam generator and to heat a mixture of gaseous hydrocarbon fuel and the steam in a reformer. The reformer converts the hydrocarbon gas to hydrogen and carbon monoxide for combustion in a combustor. A portion of the steam from the heat recovery steam generator is used to cool components, such as the stationary vanes, in the turbine section, thereby superheating the steam. The superheated steam is mixed into the hydrocarbon gas upstream of the reformer, thereby eliminating the need to raise the temperature of the expanded gas discharged from the turbine section in order to achieve effective conversion of the hydrocarbon gas.

Utilization of acetone-butanol-ethanol-water mixture obtained from biomass fermentation as renewable feedstock for hydrogen production via steam reforming: Thermodynamic and energy analyses.

PubMed

Kumar, Brajesh; Kumar, Shashi; Sinha, Shishir; Kumar, Surendra

2018-08-01

A thermodynamic equilibrium analysis on steam reforming process to utilize acetone-butanol-ethanol-water mixture obtained from biomass fermentation as biorenewable fuel has been performed to produce clean energy carrier H 2 via non-stoichiometric approach namely Gibbs free energy minimization method. The effect of process variables such as temperature (573-1473 K), pressure (1-10 atm), and steam/fuel molar feed ratio (F ABE  = 5.5-12) have been investigated on equilibrium compositions of products, H 2 , CO, CO 2 , CH 4 and solid carbon. The best suitable conditions for maximization of desired product H 2 , suppression of CH 4 , and inhibition of solid carbon are 973 K, 1 atm, steam/fuel molar feed ratio = 12. Under these conditions, the maximum molar production of hydrogen is 8.35 with negligible formation of carbon and methane. Furthermore, the energy requirement per mol of H 2 (48.96 kJ), thermal efficiency (69.13%), exergy efficiency (55.09%), exergy destruction (85.36 kJ/mol), and generated entropy (0.29 kJ/mol.K) have been achieved at same operating conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

CESIUM REMOVAL FROM TANKS 241-AN-103 & 241-SX-105 & 241-AZ-101 & 241AZ-102 COMPOSITE FOR TESTING IN BENCH SCALE STEAM REFORMER

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

DUNCAN JB; HUBER HJ

2011-04-21

This report documents the preparation of three actual Hanford tank waste samples for shipment to the Savannah River National Laboratory (SRNL). Two of the samples were dissolved saltcakes from tank 241-AN-103 (hereafter AN-103) and tank 241-SX-105 (hereafter SX-105); one sample was a supernate composite from tanks 241-AZ-101 and 241-AZ-102 (hereafter AZ-101/102). The preparation of the samples was executed following the test plans LAB-PLAN-10-00006, Test Plan for the Preparation of Samples from Hanford Tanks 241-SX-105, 241-AN-103, 241-AN-107, and LAB-PLN-l0-00014, Test Plan for the Preparation of a Composite Sample from Hanford Tanks 241-AZ-101 and 241-AZ-102 for Steam Reformer Testing at the Savannahmore » River National Laboratory. All procedural steps were recorded in laboratory notebook HNF-N-274 3. Sample breakdown diagrams for AN-103 and SX-105 are presented in Appendix A. The tank samples were prepared in support of a series of treatability studies of the Fluidized Bed Steam Reforming (FBSR) process using a Bench-Scale Reformer (BSR) at SRNL. Tests with simulants have shown that the FBSR mineralized waste form is comparable to low-activity waste glass with respect to environmental durability (WSRC-STI-2008-00268, Mineralization of Radioactive Wastes by Fluidized Bed Steam Reforming (FBSR): Comparisons to Vitreous Waste Forms and Pertinent Durability Testing). However, a rigorous assessment requires long-term performance data from FBSR product formed from actual Hanford tank waste. Washington River Protection Solutions, LLC (WRPS) has initiated a Waste Form Qualification Program (WP-5.2.1-2010-001, Fluidized Bed Steam Reformer Low-level Waste Form Qualification) to gather the data required to demonstrate that an adequate FBSR mineralized waste form can be produced. The documentation of the selection process of the three tank samples has been separately reported in RPP-48824, Sample Selection Process for Bench-Scale Steam Reforming Treatability Studies

Integrated hydrocarbon reforming system and controls

DOEpatents

Clawson, Lawrence G.; Dorson, Matthew H.; Mitchell, William L.; Nowicki, Brian J.; Thijssen, Johannes; Davis, Robert; Papile, Christopher; Rumsey, Jennifer W.; Longo, Nathan; Cross, III, James C.; Rizzo, Vincent; Kleeburg, Gunther; Rindone, Michael; Block, Stephen G.; Sun, Maria; Morriseau, Brian D.; Hagan, Mark R.; Bowers, Brian

2003-11-04

A hydrocarbon reformer system including a first reactor configured to generate hydrogen-rich reformate by carrying out at least one of a non-catalytic thermal partial oxidation, a catalytic partial oxidation, a steam reforming, and any combinations thereof, a second reactor in fluid communication with the first reactor to receive the hydrogen-rich reformate, and having a catalyst for promoting a water gas shift reaction in the hydrogen-rich reformate, and a heat exchanger having a first mass of two-phase water therein and configured to exchange heat between the two-phase water and the hydrogen-rich reformate in the second reactor, the heat exchanger being in fluid communication with the first reactor so as to supply steam to the first reactor as a reactant is disclosed. The disclosed reformer includes an auxiliary reactor configured to generate heated water/steam and being in fluid communication with the heat exchanger of the second reactor to supply the heated water/steam to the heat exchanger.

Thermochemically recuperated and steam cooled gas turbine system

DOEpatents

Viscovich, P.W.; Bannister, R.L.

1995-07-11

A gas turbine system is described in which the expanded gas from the turbine section is used to generate the steam in a heat recovery steam generator and to heat a mixture of gaseous hydrocarbon fuel and the steam in a reformer. The reformer converts the hydrocarbon gas to hydrogen and carbon monoxide for combustion in a combustor. A portion of the steam from the heat recovery steam generator is used to cool components, such as the stationary vanes, in the turbine section, thereby superheating the steam. The superheated steam is mixed into the hydrocarbon gas upstream of the reformer, thereby eliminating the need to raise the temperature of the expanded gas discharged from the turbine section in order to achieve effective conversion of the hydrocarbon gas. 4 figs.

Effect of process conditions on the steam reforming of ethanol with a nano-Ni/SiO2 catalyst.

PubMed

Wu, C; Williams, P T

2012-01-01

In this paper, a nano-Ni/SiO2 catalyst was prepared by a sol-gel method and tested for hydrogen production from ethanol steam reforming using a two-stage fixed-bed reaction system. The reaction conditions, such as reaction temperature, water/ethanol ratio and sample feeding rate, were investigated with the prepared nano-Ni/SiO2 catalyst. Brunauer-Emmett-Teller surface area and porosity, temperature-programmed oxidation, X-ray diffraction and focused ion beam (FIB)/scanning electron microscopy were used in this work to analysis the fresh and/or reacted catalysts. An extended catalyst stability test for ethanol steam reforming with the Ni/SiO2 catalyst was carried out at a reaction temperature of 600 degrees C, when the water/ethanol ratio was kept at 3.5 and sample feeding rate was 4.74 g h(-1). The results showed that a stabilized gas and hydrogen production was obtained with a potential H2 production of about 40 wt.%. Increasing the reaction temperature during ethanol steam reforming with the Ni/SiO2 catalyst resulted in an increase of gas and hydrogen production. The gas yield was slightly reduced when the water/ethanol ratio was increased from 2.0 to 3.5. However, the potential H2 production was increased. The investigation of the sample feeding rate showed that the gas production per hour was increased due to the higher sample feeding rate, but the potential H2 production was reduced.

Steam Reforming of Ethylene Glycol over MgAl₂O₄ Supported Rh, Ni, and Co Catalysts

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

Mei, Donghai; Lebarbier, Vanessa M.; Xing, Rong

Steam reforming of ethylene glycol (EG) over MgAl₂O₄ supported metal (15 wt.% Ni, 5 wt.% Rh, and 15 wt.% Co) catalysts were investigated using combined experimental and theoretical methods. Compared to highly active Rh and Ni catalysts with 100% conversion, the steam reforming activity of EG over the Co catalyst is comparatively lower with only 42% conversion under the same reaction conditions (500°C, 1 atm, 119,000 h⁻¹, S/C=3.3 mol). However, CH₄ selectivity over the Co catalyst is remarkably lower. For example, by varying the gas hour space velocity (GHSV) such that complete conversion is achieved for all the catalysts, CH₄more » selectivity for the Co catalyst is only 8%, which is much lower than the equilibrium CH₄ selectivity of ~ 24% obtained for both the Rh and Ni catalysts. Further studies show that varying H₂O concentration over the Co catalyst has a negligible effect on activity, thus indicating zero-order dependence on H₂O. These experimental results suggest that the supported Co catalyst is a promising EG steam reforming catalyst for high hydrogen production. To gain mechanistic insight for rationalizing the lower CH₃ selectivity observed for the Co catalyst, the initial decomposition reaction steps of ethylene glycol via C-O, O-H, C-H, and C-C bond scissions on the Rh(111), Ni(111) and Co(0001) surfaces were investigated using density functional theory (DFT) calculations. Despite the fact that the bond scission sequence in the EG decomposition on the three metal surfaces varies, which leads to different reaction intermediates, the lower CH₄ selectivity over the Co catalyst, as compared to the Rh and Ni catalysts, is primarily due to the higher barrier for CH₄ formation. The higher S/C ratio enhances the Co catalyst stability, which can be elucidated by the facile water dissociation and an alternative reaction path to remove the CH species as a coking precursor via the HCOH formation. This work was financially supported by the

Hydrogen production by steam reforming of liquefied natural gas over a nickel catalyst supported on mesoporous alumina xerogel

NASA Astrophysics Data System (ADS)

Seo, Jeong Gil; Youn, Min Hye; Cho, Kyung Min; Park, Sunyoung; Song, In Kyu

Mesoporous alumina xerogel (A-SG) is prepared by a sol-gel method for use as a support for a nickel catalyst. The Ni/A-SG catalyst is then prepared by an impregnation method, and is applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of the mesoporous alumina xerogel support on the catalytic performance of Ni/A-SG catalyst is investigated. For the purpose of comparison, a nickel catalyst supported on commercial alumina (A-C) is also prepared by an impregnation method (Ni/A-C). Both the hydroxyl-rich surface and the electron-deficient sites of the A-SG support enhance the dispersion of the nickel species on the support during the calcination step. The formation of the surface nickel aluminate phase in the Ni/A-SG catalyst remarkably increases the reducibility and stability of the catalyst. Furthermore, the high-surface area and the well-developed mesoporosity of the Ni/A-SG catalyst enhance the gasification of surface hydrocarbons that are adsorbed in the reaction. In the steam reforming of LNG, the Ni/A-SG catalyst exhibits a better catalytic performance than the Ni/A-C catalyst in terms of LNG conversion and hydrogen production. Moreover, the Ni/A-SG catalyst shows strong resistance toward catalyst deactivation.

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.

Hydrogen production by steam reforming of liquefied natural gas (LNG) over nickel catalysts supported on cationic surfactant-templated mesoporous aluminas

NASA Astrophysics Data System (ADS)

Seo, Jeong Gil; Youn, Min Hye; Park, Sunyoung; Jung, Ji Chul; Kim, Pil; Chung, Jin Suk; Song, In Kyu

Two types of mesoporous γ-aluminas (denoted as A-A and A-S) are prepared by a hydrothermal method under different basic conditions using cationic surfactant (cetyltrimethylammonium bromide, CTAB) as a templating agent. A-A and A-S are synthesized in a medium of ammonia solution and sodium hydroxide solution, respectively. Ni/γ-Al 2O 3 catalysts (Ni/A-A and Ni/A-S) are then prepared by an impregnation method, and are applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of a mesoporous γ-Al 2O 3 support on the catalytic performance of Ni/γ-Al 2O 3 is investigated. The identity of basic solution strongly affects the physical properties of the A-A and A-S supports. The high surface-area of the mesoporous γ-aluminas and the strong metal-support interaction of supported catalysts greatly enhance the dispersion of nickel species on the catalyst surface. The well-developed mesopores of the Ni/A-A and Ni/A-S catalysts prohibit the polymerization of carbon species on the catalyst surface during the reaction. In the steam reforming of LNG, both Ni/A-A and Ni/A-S catalysts give better catalytic performance than the nickel catalyst supported on commercial γ-Al 2O 3 (Ni/A-C). In addition, the Ni/A-A catalyst is superior to the Ni/A-S catalyst. The relatively strong metal-support interaction of Ni/A-A catalyst effectively suppresses the sintering of metallic nickel and the carbon deposition in the steam reforming of LNG. The large pores of the Ni/A-A catalyst also play an important role in enhancing internal mass transfer during the reaction.

Performance analysis of a SOFC under direct internal reforming conditions

NASA Astrophysics Data System (ADS)

Janardhanan, Vinod M.; Heuveline, Vincent; Deutschmann, Olaf

This paper presents the performance analysis of a planar solid-oxide fuel cell (SOFC) under direct internal reforming conditions. A detailed solid-oxide fuel cell model is used to study the influences of various operating parameters on cell performance. Significant differences in efficiency and power density are observed for isothermal and adiabatic operational regimes. The influence of air number, specific catalyst area, anode thickness, steam to carbon (s/c) ratio of the inlet fuel, and extend of pre-reforming on cell performance is analyzed. In all cases except for the case of pre-reformed fuel, adiabatic operation results in lower performance compared to isothermal operation. It is further discussed that, though direct internal reforming may lead to cost reduction and increased efficiency by effective utilization of waste heat, the efficiency of the fuel cell itself is higher for pre-reformed fuel compared to non-reformed fuel. Furthermore, criteria for the choice of optimal operating conditions for cell stacks operating under direct internal reforming conditions are discussed.

Thermodynamic analyses of hydrogen production from sub-quality natural gas. Part II: Steam reforming and autothermal steam reforming

NASA Astrophysics Data System (ADS)

Huang, Cunping; T-Raissi, Ali

Part I of this paper analyzed sub-quality natural gas (SQNG) pyrolysis and autothermal pyrolysis. Production of hydrogen via direct thermolysis of SQNGs produces only 2 mol of hydrogen and 1 mol of carbon per mole of methane (CH 4). Steam reforming of SQNG (SRSQNG) could become a more effective approach because the processes produce two more moles of hydrogen via water splitting. A Gibbs reactor unit operation in the AspenPlus™ chemical process simulator was employed to accomplish equilibrium calculations for the SQNG + H 2O and SQNG + H 2O + O 2 systems. The results indicate that water and oxygen inlet flow rates do not significantly affect the decomposition of hydrogen sulfide (H 2S) at temperatures lower than 1000 °C. The major co-product of the processes is carbonyl sulfide (COS) while sulfur dimer (S 2) and carbon disulfide (CS 2) are minor by-products within this temperature range. At higher temperatures (>1300 °C), CS 2 and S 2 become major co-products. No sulfur dioxide (SO 2) or sulfur trioxide (SO 3) is formed during either SRSQNG or autothermal SRSQNG processes, indicating that no environmentally harmful acidic gases are generated.

Effect of SiO 2-ZrO 2 supports prepared by a grafting method on hydrogen production by steam reforming of liquefied natural gas over Ni/SiO 2-ZrO 2 catalysts

NASA Astrophysics Data System (ADS)

Seo, Jeong Gil; Youn, Min Hye; Song, In Kyu

SiO 2-ZrO 2 supports with various zirconium contents are prepared by grafting a zirconium precursor onto the surface of commercial Carbosil silica. Ni(20 wt.%)/SiO 2-ZrO 2 catalysts are then prepared by an impregnation method, and are applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of SiO 2-ZrO 2 supports on the performance of the Ni(20 wt.%)/SiO 2-ZrO 2 catalysts is investigated. SiO 2-ZrO 2 prepared by a grafting method serves as an efficient support for the nickel catalyst in the steam reforming of LNG. Zirconia enhances the resistance of silica to steam significantly and increases the interaction between nickel and the support, and furthermore, prevents the growth of nickel oxide species during the calcination process through the formation of a ZrO 2-SiO 2 composite structure. The crystalline structures and catalytic activities of the Ni(20 wt.%)/SiO 2-ZrO 2 catalysts are strongly influenced by the amount of zirconium grafted. The conversion of LNG and the yield of hydrogen show volcano-shaped curves with respect to zirconium content. Among the catalysts tested, the Ni(20 wt.%)/SiO 2-ZrO 2 (Zr/Si = 0.54) sample shows the best catalytic performance in terms of both LNG conversion and hydrogen yield. The well-developed and pure tetragonal phase of ZrO 2-SiO 2 (Zr/Si = 0.54) appears to play an important role in the adsorption of steam and subsequent spillover of steam from the support to the active nickel. The small particle size of the metallic nickel in the Ni(20 wt.%)/SiO 2-ZrO 2 (Zr/Si = 0.54) catalyst is also responsible for its high performance.

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.

Steam reforming of ethanol for hydrogen production over Cu/Co-Mg-Al-based catalysts prepared by hydrotalcite route.

PubMed

Homsi, Doris; Rached, Jihane Abou; Aouad, Samer; Gennequin, Cédric; Dahdah, Eliane; Estephane, Jane; Tidahy, Haingomalala Lucette; Aboukaïs, Antoine; Abi-Aad, Edmond

2017-04-01

The performances of different 5Cu/Co x Mg 6-x Al 2 (x = 0; 2; 4; 6) catalysts prepared by the wet impregnation method were investigated in the ethanol steam-reforming reaction (ESR) at 450 °C during 4 h under a steam/ethanol ratio of 3 (S/E = 3). The best catalyst among the prepared solids was 5Cu/Co 6 Al 2 as it showed a complete ethanol conversion and the highest hydrogen and carbon dioxide productivities. However, following 50 h of aging, the catalyst deactivated due to the formation of a high amount of carbonaceous products detected by differential scanning calorimetry/thermogravimetry. On the other hand, the 5Cu/Co 2 Mg 4 Al 2 catalyst showed a much lower quantity of coke deposition with no deactivation due to the basic character conferred by the magnesium oxide phase.

Reforming of natural gas—hydrogen generation for small scale stationary fuel cell systems

NASA Astrophysics Data System (ADS)

Heinzel, A.; Vogel, B.; Hübner, P.

The reforming of natural gas to produce hydrogen for fuel cells is described, including the basic concepts (steam reforming or autothermal reforming) and the mechanisms of the chemical reactions. Experimental work has been done with a compact steam reformer, and a prototype of an experimental reactor for autothermal reforming was tested, both containing a Pt-catalyst on metallic substrate. Experimental results on the steam reforming system and a comparison of the steam reforming process with the autothermal process are given.

Statistical validation and an empirical model of hydrogen production enhancement found by utilizing passive flow disturbance in the steam-reformation process

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

Erickson, Paul A.; Liao, Chang-hsien

2007-11-15

A passive flow disturbance has been proven to enhance the conversion of fuel in a methanol-steam reformer. This study presents a statistical validation of the experiment based on a standard 2{sup k} factorial experiment design and the resulting empirical model of the enhanced hydrogen producing process. A factorial experiment design was used to statistically analyze the effects and interactions of various input factors in the experiment. Three input factors, including the number of flow disturbers, catalyst size, and reactant flow rate were investigated for their effects on the fuel conversion in the steam-reformation process. Based on the experimental results, anmore » empirical model was developed and further evaluated with an uncertainty analysis and interior point data. (author)« less

The Development of a Small High Speed Steam Microturbine Generator System

NASA Astrophysics Data System (ADS)

Alford, Adrian; Nichol, Philip; Frisby, Ben

2015-08-01

The efficient use of energy is paramount in every kind of business today. Steam is a widely used energy source. In many situations steam is generated at high pressures and then reduced in pressure through control valves before reaching point of use. An opportunity was identified to convert some of the energy at the point of pressure reduction into electricity. This can be accomplished using steam turbines driving alternators on large scale systems. To take advantage of a market identified for small scale systems, a microturbine generator was designed based on a small high speed turbo machine. This gave rise to a number of challenges which are described with the solutions adopted. The challenges included aerodynamic design of high efficiency impellers, sealing of a high speed shaft, thrust control and material selection to avoid steam erosion. The machine was packaged with a sophisticated control system to allow connection to the electricity grid. Some of the challenges in packaging the machine are also described. The Spirax Sarco TurboPower has now concluded performance and initial endurance tests which are described with a summary of the results.

Additive Manufacturing of Catalyst Substrates for Steam-Methane Reforming

NASA Astrophysics Data System (ADS)

Kramer, Michelle; McKelvie, Millie; Watson, Matthew

2018-01-01

Steam-methane reforming is a highly endothermic reaction, which is carried out at temperatures up to 1100 °C and pressures up to 3000 kPa, typically with a Ni-based catalyst distributed over a substrate of discrete alumina pellets or beads. Standard pellet geometries (spheres, hollow cylinders) limit the degree of mass transfer between gaseous reactants and catalyst. Further, heat is supplied to the exterior of the reactor wall, and heat transfer is limited due to the nature of point contacts between the reactor wall and the substrate pellets. This limits the degree to which the process can be intensified, as well as limiting the diameter of the reactor wall. Additive manufacturing now gives us the capability to design structures with tailored heat and mass transfer properties, not only within the packed bed of the reactor, but also at the interface between the reactor wall and the packed bed. In this work, the use of additive manufacturing to produce monolithic-structured catalyst substrate models, made from acrylonitrile-butadiene-styrene, with enhanced conductive heat transfer is described. By integrating the reactor wall into the catalyst substrate structure, the effective thermal conductivity increased by 34% from 0.122 to 0.164 W/(m K).

Energy and exergy analysis of an ethanol reforming process for solid oxide fuel cell applications.

PubMed

Tippawan, Phanicha; Arpornwichanop, Amornchai

2014-04-01

The fuel processor in which hydrogen is produced from fuels is an important unit in a fuel cell system. The aim of this study is to apply a thermodynamic concept to identify a suitable reforming process for an ethanol-fueled solid oxide fuel cell (SOFC). Three different reforming technologies, i.e., steam reforming, partial oxidation and autothermal reforming, are considered. The first and second laws of thermodynamics are employed to determine an energy demand and to describe how efficiently the energy is supplied to the reforming process. Effect of key operating parameters on the distribution of reforming products, such as H2, CO, CO2 and CH4, and the possibility of carbon formation in different ethanol reformings are examined as a function of steam-to-ethanol ratio, oxygen-to-ethanol ratio and temperatures at atmospheric pressure. Energy and exergy analysis are performed to identify the best ethanol reforming process for SOFC applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

Methanol steam reforming over Ni-CeO 2 model and powder catalysts: Pathways to high stability and selectivity for H 2/CO 2 production

DOE PAGES

Liu, Zongyuan; Yao, Siyu; Johnston-Peck, Aaron; ...

2017-08-25

Here, nickel-ceria has been reported as a very good catalysts for the reforming of methane. Here, the methanol steam reforming reaction on both powder (Ni-CeO 2) and model (Ni-CeO 2-x(111)) catalysts was investigated. The active phase evolution and surface species transformation on powder catalysts were studied via in situ X-ray diffraction (XRD) and diffuse reflectance infrared transform spectroscopy (DRIFTS). Phase transitions of NiO → NiC → Ni and CeO 2 → CeO 2-x were observed during the reaction. The simultaneous production of H 2/CO 2 demonstrates that the active phase of the catalysts contains metallic Ni supported over partially reducedmore » ceria. The DRIFTS experiments indicate that a methoxy to formate transition is associated with the reduction of ceria whereas the formation of carbonate species results from the presence of metallic Ni. A study of the reaction of methanol with Ni-CeO 2-x(111) by X-ray photoelectron spectroscopy (XPS) points to the essential role of metal-support interactions in an oxygen transfer from ceria to Ni that contributes to the high selectivity of the catalysts.« less

Methanol steam reforming over Ni-CeO 2 model and powder catalysts: Pathways to high stability and selectivity for H 2/CO 2 production

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

Liu, Zongyuan; Yao, Siyu; Johnston-Peck, Aaron

Here, nickel-ceria has been reported as a very good catalysts for the reforming of methane. Here, the methanol steam reforming reaction on both powder (Ni-CeO 2) and model (Ni-CeO 2-x(111)) catalysts was investigated. The active phase evolution and surface species transformation on powder catalysts were studied via in situ X-ray diffraction (XRD) and diffuse reflectance infrared transform spectroscopy (DRIFTS). Phase transitions of NiO → NiC → Ni and CeO 2 → CeO 2-x were observed during the reaction. The simultaneous production of H 2/CO 2 demonstrates that the active phase of the catalysts contains metallic Ni supported over partially reducedmore » ceria. The DRIFTS experiments indicate that a methoxy to formate transition is associated with the reduction of ceria whereas the formation of carbonate species results from the presence of metallic Ni. A study of the reaction of methanol with Ni-CeO 2-x(111) by X-ray photoelectron spectroscopy (XPS) points to the essential role of metal-support interactions in an oxygen transfer from ceria to Ni that contributes to the high selectivity of the catalysts.« less

A light hydrocarbon fuel processor producing high-purity hydrogen

NASA Astrophysics Data System (ADS)

Löffler, Daniel G.; Taylor, Kyle; Mason, Dylan

This paper discusses the design process and presents performance data for a dual fuel (natural gas and LPG) fuel processor for PEM fuel cells delivering between 2 and 8 kW electric power in stationary applications. The fuel processor resulted from a series of design compromises made to address different design constraints. First, the product quality was selected; then, the unit operations needed to achieve that product quality were chosen from the pool of available technologies. Next, the specific equipment needed for each unit operation was selected. Finally, the unit operations were thermally integrated to achieve high thermal efficiency. Early in the design process, it was decided that the fuel processor would deliver high-purity hydrogen. Hydrogen can be separated from other gases by pressure-driven processes based on either selective adsorption or permeation. The pressure requirement made steam reforming (SR) the preferred reforming technology because it does not require compression of combustion air; therefore, steam reforming is more efficient in a high-pressure fuel processor than alternative technologies like autothermal reforming (ATR) or partial oxidation (POX), where the combustion occurs at the pressure of the process stream. A low-temperature pre-reformer reactor is needed upstream of a steam reformer to suppress coke formation; yet, low temperatures facilitate the formation of metal sulfides that deactivate the catalyst. For this reason, a desulfurization unit is needed upstream of the pre-reformer. Hydrogen separation was implemented using a palladium alloy membrane. Packed beds were chosen for the pre-reformer and reformer reactors primarily because of their low cost, relatively simple operation and low maintenance. Commercial, off-the-shelf balance of plant (BOP) components (pumps, valves, and heat exchangers) were used to integrate the unit operations. The fuel processor delivers up to 100 slm hydrogen >99.9% pure with <1 ppm CO, <3 ppm CO 2. The

Influence of the Crystal Structure of Titanium Oxide on the Catalytic Activity of Rh/TiO2 in Steam Reforming of Propane at Low Temperature.

PubMed

Yu, Lin; Sato, Katsutoshi; Toriyama, Takaaki; Yamamoto, Tomokazu; Matsumura, Syo; Nagaoka, Katsutoshi

2018-06-21

Solid oxide fuel cells (SOFCs) with liquefied petroleum gas (LPG) reduce CO 2 emissions due to their high-energy-conversion efficiency. Although SOFCs can convert LPG directly, coking occurs easily by decomposition of hydrocarbons, including C-C bonds on the electrode of fuel cell stacks. It is therefore necessary to develop an active steam pre-reforming catalyst that eliminates the hydrocarbons at low temperature, in which waste heat of SOFCs is used. Herein, we show that the crystal structure of the TiO 2 that anchors Rh particles is crucial for catalytic activity of Rh/TiO 2 catalysts for propane pre-reforming. Our experimental results revealed that strong metal support interaction (SMSI) induced during H 2 pre-reduction were optimized over Rh/TiO 2 with a rutile structure; this catalyst catalyzed the reaction much more effectively than conventional Rh/γ-Al 2 O 3 . In contrast, the SMSI was too strong for Rh/TiO 2 with an anatase structure, and the surface of the Rh particles was therefore covered mostly with partially reduced TiO 2 . The result was very low activity. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Functioning efficiency of intermediate coolers of multistage steam-jet ejectors of steam turbines

NASA Astrophysics Data System (ADS)

Aronson, K. E.; Ryabchikov, A. Yu.; Brodov, Yu. M.; Zhelonkin, N. V.; Murmanskii, I. B.

2017-03-01

Designs of various types of intermediate coolers of multistage ejectors are analyzed and thermal effectiveness and gas-dynamic resistance of coolers are estimated. Data on quantity of steam condensed from steam-air mixture in stage I of an ejector cooler was obtained on the basis of experimental results. It is established that the amount of steam condensed in the cooler constitutes 0.6-0.7 and is almost independent of operating steam pressure (and, consequently, of steam flow) and air amount in steam-air mixture. It is suggested to estimate the amount of condensed steam in a cooler of stage I based on comparison of computed and experimental characteristics of stage II. Computation taking this hypothesis for main types of mass produced multistage ejectors into account shows that 0.60-0.85 of steam amount should be condensed in stage I of the cooler. For ejectors with "pipe-in-pipe" type coolers (EPO-3-200) and helical coolers (EO-30), amount of condensed steam may reach 0.93-0.98. Estimation of gas-dynamic resistance of coolers shows that resistance from steam side in coolers with built-in and remote pipe bundle constitutes 100-300 Pa. Gas-dynamic resistance of "pipein- pipe" and helical type coolers is significantly higher (3-6 times) compared with pipe bundle. However, performance by "dry" (atmospheric) air is higher for ejectors with relatively high gas-dynamic resistance of coolers than those with low resistance at approximately equal operating flow values of ejectors.

How did China's foreign exchange reform affect the efficiency of foreign exchange market?

NASA Astrophysics Data System (ADS)

Ning, Ye; Wang, Yiming; Su, Chi-wei

2017-10-01

This study compares the market efficiency of China's onshore and offshore foreign exchange markets before and after the foreign exchange reform on August 11, 2015. We use the multifractal detrended fluctuation analysis of the onshore and offshore RMB/USD spot exchange rate series as basis. We then find that the onshore foreign exchange market before the reform has the lowest market efficiency, which increased after the reform. The offshore foreign exchange market before the reform has the highest market efficiency, which dropped after the reform. This finding implies the increased efficiency of the onshore foreign exchange market and the loss of efficiency in the offshore foreign exchange market. We also find that the offshore foreign exchange market is more efficient than the onshore market and that the gap shrank after the reform. Changes in intervention of the People's Bank of China since the reform is a possible explanation for the changes in the efficiency of the foreign exchange market.

Radioactive Demonstrations Of Fluidized Bed Steam Reforming (FBSR) With Hanford Low Activity Wastes

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

Jantzen, C. M.; Crawford, C. L.; Burket, P. R.

Several supplemental technologies for treating and immobilizing Hanford low activity waste (LAW) are being evaluated. One immobilization technology being considered is Fluidized Bed Steam Reforming (FBSR) which offers a low temperature (700-750?C) continuous method by which wastes high in organics, nitrates, sulfates/sulfides, or other aqueous components may be processed into a crystalline ceramic (mineral) waste form. The granular waste form produced by co-processing the waste with kaolin clay has been shown to be as durable as LAW glass. The FBSR granular product will be monolithed into a final waste form. The granular component is composed of insoluble sodium aluminosilicate (NAS)more » feldspathoid minerals such as sodalite. Production of the FBSR mineral product has been demonstrated both at the industrial, engineering, pilot, and laboratory scales on simulants. Radioactive testing at SRNL commenced in late 2010 to demonstrate the technology on radioactive LAW streams which is the focus of this study.« less

Steam atmosphere drying exhaust steam recompression system

DOEpatents

Becker, F.E.; Smolensky, L.A.; Doyle, E.F.; DiBella, F.A.

1994-03-08

This invention relates to a heated steam atmosphere drying system comprising dryer in combination with an exhaust recompression system which is extremely energy efficient and eliminates dangers known to air dryers. The system uses superheated steam as the drying medium, which recirculates through the system where its heat of evaporation and heat of compression is recovered, thereby providing a constant source of heat to the drying chamber. The dryer has inlets whereby feedstock and superheated steam are fed therein. High heat transfer and drying rates are achieved by intimate contact of the superheated steam with the particles being dried. The dryer comprises a vessel which enables the feedstock and steam to enter and recirculate together. When the feedstock becomes dry it will exit the dryer with the steam and become separated from the steam through the use of a curvilinear louver separator (CLS). The CLS enables removal of fine and ultrafine particles from the dryer. Water vapor separated from the particles in the CLS as superheated steam, may then be recovered and recirculated as steam through the use of a compressor to either directly or indirectly heat the dryer, and a heat exchanger or a heater to directly provide heat to the dryer. This system not only provides a very efficient heat transfer system but results in a minimum carry-over of ultrafine particles thereby eliminating any explosive hazard. 17 figures.

Steam atmosphere drying exhaust steam recompression system

DOEpatents

Becker, Frederick E.; Smolensky, Leo A.; Doyle, Edward F.; DiBella, Francis A.

1994-01-01

This invention relates to a heated steam atmosphere drying system comprising dryer in combination with an exhaust recompression system which is extremely energy efficient and eliminates dangers known to air dryers. The system uses superheated steam as the drying medium, which recirculated through the system where its heat of evaporation and heat of compression is recovered, thereby providing a constant source of heat to the drying chamber. The dryer has inlets whereby feedstock and superheated steam are fed therein. High heat transfer and drying rates are achieved by intimate contact of the superheated steam with the particles being dried The dryer comprises a vessel which enables the feedstock and steam to enter recirculate together. When the feedstock becomes dry it will exit the dryer with the steam and become separated from the steam through the use of a curvilinear louver separator (CLS). The CLS enables removal of fine and ultrafine particles from the dryer. Water vapor separated from the particles in the CLS as superheated steam, may then be recovered and recirculated as steam through the use of a compressor to either directly or indirectly heat the dryer, and a heat exchanger or a heater to directly provide heat to the dryer. This system not only provides a very efficient heat transfer system but results in a minimum carry-over of ultrafine particles thereby eliminating any explosive hazard.

Formulation of steam-methane reforming rate in Ni-YSZ porous anode of solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Sugihara, Shinichi; Kawamura, Yusuke; Iwai, Hiroshi

2018-02-01

The steam-methane reforming reaction on a Ni-YSZ (yttria-stabilized zirconia) cermet was experimentally investigated under atmospheric pressure and in the temperature range from 650 to 750 °C. We examined the effects of the partial pressures of methane and steam in the supply gas on the reaction rate. The experiments were conducted with a low Ni contained Ni-YSZ cermet sheet of thickness 0.1 mm. Its porous microstructure and accompanied parameters were quantified using the FIB-SEM (focused ion beam scanning electron microscopy) technique. A power-law-type rate equation incorporating the reaction-rate-limiting conditions was obtained on the basis of the unit surface area of the Ni-pore contact surface in the cermet. The kinetics indicated a strong positive dependence on the methane partial pressure and a negative dependence on the steam partial pressure. The obtained rate equation successfully reproduced the experimental results for Ni-YSZ samples having different microstructures in the case of low methane consumption. The equation also reproduced the limiting-reaction behaviours at different temperatures.

Methanol steam reforming promoted by molten salt-modified platinum on alumina catalysts.

PubMed

Kusche, Matthias; Agel, Friederike; Ní Bhriain, Nollaig; Kaftan, Andre; Laurin, Mathias; Libuda, Jörg; Wasserscheid, Peter

2014-09-01

We herein describe a straight forward procedure to increase the performance of platinum-on-alumina catalysts in methanol steam reforming by applying an alkali hydroxide coating according to the "solid catalyst with ionic liquid layer" (SCILL) approach. We demonstrate by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature-programmed desorption (TPD) studies that potassium doping plays an important role in the catalyst activation. Moreover, the hygroscopic nature and the basicity of the salt modification contribute to the considerable enhancement in catalytic performance. During reaction, a partly liquid film of alkali hydroxides/carbonates forms on the catalyst/alumina surface, thus significantly enhancing the availability of water at the catalytically active sites. Too high catalyst pore fillings with salt introduce a considerable mass transfer barrier into the system as indicated by kinetic studies. Thus, the optimum interplay between beneficial catalyst modification and detrimental mass transfer effects had to be identified and was found on the applied platinum-on-alumina catalyst at KOH loadings around 7.5 mass%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methanol Steam Reforming Promoted by Molten Salt-Modified Platinum on Alumina Catalysts

PubMed Central

Kusche, Matthias; Agel, Friederike; Ní Bhriain, Nollaig; Kaftan, Andre; Laurin, Mathias; Libuda, Jörg; Wasserscheid, Peter

2014-01-01

We herein describe a straight forward procedure to increase the performance of platinum-on-alumina catalysts in methanol steam reforming by applying an alkali hydroxide coating according to the “solid catalyst with ionic liquid layer” (SCILL) approach. We demonstrate by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature-programmed desorption (TPD) studies that potassium doping plays an important role in the catalyst activation. Moreover, the hygroscopic nature and the basicity of the salt modification contribute to the considerable enhancement in catalytic performance. During reaction, a partly liquid film of alkali hydroxides/carbonates forms on the catalyst/alumina surface, thus significantly enhancing the availability of water at the catalytically active sites. Too high catalyst pore fillings with salt introduce a considerable mass transfer barrier into the system as indicated by kinetic studies. Thus, the optimum interplay between beneficial catalyst modification and detrimental mass transfer effects had to be identified and was found on the applied platinum-on-alumina catalyst at KOH loadings around 7.5 mass %. PMID:25124120

Highly Active and Stable MgAl2O4 Supported Rh and Ir Catalysts for Methane Steam Reforming: A Combined Experimental and Theoretical Study

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

Mei, Donghai; Glezakou, Vassiliki Alexandra; Lebarbier, Vanessa MC

2014-07-01

In this work we present a combined experimental and theoretical investigation of stable MgAl2O4 spinel-supported Rh and Ir catalysts for the steam methane reforming (SMR) reaction. Firstly, catalytic performance for a series of noble metal catalysts supported on MgAl2O4 spinel was evaluated for SMR at 600-850°C. Turnover rate at 850°C follows the order: Pd > Pt > Ir > Rh > Ru > Ni. However, Rh and Ir were found to have the best combination of activity and stability for methane steam reforming in the presence of simulated biomass-derived syngas. It was found that highly dispersed ~2 nm Rh andmore » ~1 nm Ir clusters were formed on the MgAl2O4 spinel support. Scanning Transition Electron Microscopy (STEM) images show that excellent dispersion was maintained even under challenging high temperature conditions (e.g. at 850°C in the presence of steam) while Ir and Rh catalysts supported on Al2O3 were observed to sinter at increased rates under the same conditions. These observations were further confirmed by ab initio molecular dynamics (AIMD) simulations which find that ~1 nm Rh and Ir particles (50-atom cluster) bind strongly to the MgAl2O4 surfaces via a redox process leading to a strong metal-support interaction, thus helping anchor the metal clusters and reduce the tendency to sinter. Density functional theory (DFT) calculations suggest that these supported smaller Rh and Ir particles have a lower work function than larger more bulk-like ones, which enables them to activate both water and methane more effectively than larger particles, yet have a minimal influence on the relative stability of coke precursors. In addition, theoretical mechanistic studies were used to probe the relationship between structure and reactivity. Consistent with the experimental observations, our theoretical modeling results also suggest that the small spinel-supported Ir particle catalyst is more active than the counterpart of Rh catalyst for SMR. This work was financially supported

Understanding of catalyst deactivation caused by sulfur poisoning and carbon deposition in steam reforming of liquid hydrocarbon fuels

NASA Astrophysics Data System (ADS)

Xie, Chao

2011-12-01

The present work was conducted to develop a better understanding on the catalyst deactivation in steam reforming of sulfur-containing liquid hydrocarbon fuels for hydrogen production. Steam reforming of Norpar13 (a liquid hydrocarbon fuel from Exxon Mobile) without and with sulfur was performed on various metal catalysts (Rh, Ru, Pt, Pd, and Ni) supported on different materials (Al2O3, CeO2, SiO2, MgO, and CeO2- Al2O3). A number of characterization techniques were applied to study the physicochemical properties of these catalysts before and after the reactions. Especially, X-ray absorption near edge structure (XANES) spectroscopy was intensively used to investigate the nature of sulfur and carbon species in the used catalysts to reveal the catalyst deactivation mechanism. Among the tested noble metal catalysts (Rh, Ru, Pt, and Pd), Rh catalyst is the most sulfur tolerant. Al2O3 and CeO2 are much better than SiO2 and MgO as the supports for the Rh catalyst to reform sulfur-containing hydrocarbons. The good sulfur tolerance of Rh/Al2O3 can be attributed to the acidic nature of the Al2O3 support and its small Rh crystallites (1-3 nm) as these characteristics facilitate the formation of electron-deficient Rh particles with high sulfur tolerance. The good catalytic performance of Rh/CeO2 in the presence of sulfur can be ascribed to the promotion effect of CeO2 on carbon gasification, which significantly reduced the carbon deposition on the Rh/CeO2catalyst. Steam reforming of Norpar13 in the absence and presence of sulfur was further carried out over CeO2-Al2O3 supported monometallic Ni and Rh and bimetallic Rh-Ni catalysts at 550 and 800 °C. Both monometallic catalysts rapidly deactivated at 550 °C, iv and showed poor sulfur tolerance. Although ineffective for the Ni catalyst, increasing the temperature to 800 °C dramatically improved the sulfur tolerance of the Rh catalyst. Sulfur K-edge XANES revealed that metal sulfide and organic sulfide are the dominant sulfur

Metal catalysts for steam reforming of tar derived from the gasification of lignocellulosic biomass.

PubMed

Li, Dalin; Tamura, Masazumi; Nakagawa, Yoshinao; Tomishige, Keiichi

2015-02-01

Biomass gasification is one of the most important technologies for the conversion of biomass to electricity, fuels, and chemicals. The main obstacle preventing the commercial application of this technology is the presence of tar in the product gas. Catalytic reforming of tar appears a promising approach to remove tar and supported metal catalysts are among the most effective catalysts. Nevertheless, improvement of catalytic performances including activity, stability, resistance to coke deposition and aggregation of metal particles, as well as catalyst regenerability is greatly needed. This review focuses on the design and catalysis of supported metal catalysts for the removal of tar in the gasification of biomass. The recent development of metal catalysts including Rh, Ni, Co, and their alloys for steam reforming of biomass tar and tar model compounds is introduced. The role of metal species, support materials, promoters, and their interfaces is described. Copyright © 2014 Elsevier Ltd. All rights reserved.

Efficiency gain of solid oxide fuel cell systems by using anode offgas recycle - Results for a small scale propane driven unit

NASA Astrophysics Data System (ADS)

Dietrich, Ralph-Uwe; Oelze, Jana; Lindermeir, Andreas; Spitta, Christian; Steffen, Michael; Küster, Torben; Chen, Shaofei; Schlitzberger, Christian; Leithner, Reinhard

The transfer of high electrical efficiencies of solid oxide fuel cells (SOFC) into praxis requires appropriate system concepts. One option is the anode-offgas recycling (AOGR) approach, which is based on the integration of waste heat using the principle of a chemical heat pump. The AOGR concept allows a combined steam- and dry-reforming of hydrocarbon fuel using the fuel cell products steam and carbon dioxide. SOFC fuel gas of higher quantity and quality results. In combination with internal reuse of waste heat the system efficiency increases compared to the usual path of partial oxidation (POX). The demonstration of the AOGR concept with a 300 Wel-SOFC stack running on propane required: a combined reformer/burner-reactor operating in POX (start-up) and AOGR modus; a hotgas-injector for anode-offgas recycling to the reformer; a dynamic process model; a multi-variable process controller; full system operation for experimental proof of the efficiency gain. Experimental results proof an efficiency gain of 18 percentage points (η·POX = 23%, η·AOGR = 41%) under idealized lab conditions. Nevertheless, further improvements of injector performance, stack fuel utilization and additional reduction of reformer reformer O/C ratio and system pressure drop are required to bring this approach into self-sustaining operation.

On direct internal methane steam reforming kinetics in operating solid oxide fuel cells with nickel-ceria anodes

NASA Astrophysics Data System (ADS)

Thallam Thattai, A.; van Biert, L.; Aravind, P. V.

2017-12-01

Major operating challenges remain to safely operate methane fuelled solid oxide fuel cells due to undesirable temperature gradients across the porous anode and carbon deposition. This article presents an experimental study on methane steam reforming (MSR) global kinetics for single operating SOFCs with Ni-GDC (gadolinium doped ceria) anodes for low steam to carbon (S/C) ratios and moderate current densities. The study points out the hitherto insufficient research on MSR global and intrinsic kinetics for operating SOFCs with complete Ni-ceria anodes. Further, it emphasizes the need to develop readily applicable global kinetic models as a subsequent step from previously reported state-of-art and complex intrinsic models. Two rate expressions of the Power law (PL) and Langmuir-Hinshelwood (LH) type have been compared and based on the analysis, limitations of using previously proposed rate expressions for Ni catalytic beds to study MSR kinetics for complete cermet anodes have been identified. Firstly, it has been shown that methane reforming on metallic (Ni) current collectors may not be always negligible, contrary to literature reports. Both PL and LH kinetic models predict significantly different local MSR reaction rate and species partial pressure distributions along the normalized reactor length, indicating a strong need for further experimental verifications.

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 5: Combined gas-steam turbine cycles. [energy conversion efficiency in electric power plants

NASA Technical Reports Server (NTRS)

Amos, D. J.; Foster-Pegg, R. W.; Lee, R. M.

1976-01-01

The energy conversion efficiency of gas-steam turbine cycles was investigated for selected combined cycle power plants. Results indicate that it is possible for combined cycle gas-steam turbine power plants to have efficiencies several point higher than conventional steam plants. Induction of low pressure steam into the steam turbine is shown to improve the plant efficiency. Post firing of the boiler of a high temperature combined cycle plant is found to increase net power but to worsen efficiency. A gas turbine pressure ratio of 12 to 1 was found to be close to optimum at all gas turbine inlet temperatures that were studied. The coal using combined cycle plant with an integrated low-Btu gasifier was calculated to have a plant efficiency of 43.6%, a capitalization of $497/kW, and a cost of electricity of 6.75 mills/MJ (24.3 mills/kwh). This combined cycle plant should be considered for base load power generation.

Liquid Fuel Production from Biomass via High Temperature Steam Electrolysis

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

Grant L. Hawkes; Michael G. McKellar

2009-11-01

A process model of syngas production using high temperature electrolysis and biomass gasification is presented. Process heat from the biomass gasifier is used to heat steam for the hydrogen production via the high temperature steam electrolysis process. Hydrogen from electrolysis allows a high utilization of the biomass carbon for syngas production. Oxygen produced form the electrolysis process is used to control the oxidation rate in the oxygen-fed biomass gasifier. Based on the gasifier temperature, 94% to 95% of the carbon in the biomass becomes carbon monoxide in the syngas (carbon monoxide and hydrogen). Assuming the thermal efficiency of the powermore » cycle for electricity generation is 50%, (as expected from GEN IV nuclear reactors), the syngas production efficiency ranges from 70% to 73% as the gasifier temperature decreases from 1900 K to 1500 K. Parametric studies of system pressure, biomass moisture content and low temperature alkaline electrolysis are also presented.« less

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.

Hydrogen Production by Steam Reforming of Liquefied Natural Gas (LNG) Over Nickel-Phosphorus-Alumina Xerogel Catalyst Prepared by a Carbon-Templating Epoxide-Driven Sol-Gel Method.

PubMed

Bang, Yongju; Park, Seungwon; Han, Seung Ju; Yoo, Jaekyeong; Choi, Jung Ho; Kang, Tae Hun; Lee, Jinwon; Song, In Kyu

2016-05-01

A nickel-phosphorus-alumina xerogel catalyst was prepared by a carbon-templating epoxide-driven sol-gel method (denoted as CNPA catalyst), and it was applied to the hydrogen production by steam reforming of liquefied natural gas (LNG). For comparison, a nickel-phosphorus-alumina xerogel catalyst was also prepared by a similar method in the absence of carbon template (denoted as NPA catalyst). The effect of carbon template addition on the physicochemical properties and catalytic activities of the catalysts in the steam reforming of LNG was investigated. Both CNPA and NPA catalysts showed excellent textural properties with well-developed mesoporous structure. However, CNPA catalyst retained a more reducible nickel aluminate phase than NPA catalyst. XRD analysis of the reduced CNPA and NPA catalysts revealed that nickel sintering on the CNPA catalyst was suppressed compared to that on the NPA catalyst. From H2-TPD and CH4-TPD measurements of the reduced CNPA and NPA catalysts, it was also revealed that CNPA catalyst with large amount of hydrogen uptake and strong hydrogen-binding sites showed larger amount of methane adsorption than NPA catalyst. In the hydrogen production by steam reforming of LNG, CNPA catalyst with large methane adsorption capacity showed a better catalytic activity than NPA catalyst.

A high-temperature gas-and-steam turbine plant operating on combined fuel

NASA Astrophysics Data System (ADS)

Klimenko, A. V.; Milman, O. O.; Shifrin, B. A.

2015-11-01

A high-temperature gas-steam turbine plant (GSTP) for ultrasupercritical steam conditions is proposed based on an analysis of prospects for the development of power engineering around the world and in Russia up to 2040. The performance indicators of a GSTP using steam from a coal-fired boiler with a temperature of 560-620°C with its superheating to 1000-1500°C by firing natural gas with oxygen in a mixingtype steam superheater are analyzed. The thermal process circuit and design of a GSTP for a capacity of 25 MW with the high- and intermediate-pressure high-temperature parts with the total efficiency equal to 51.7% and the natural gas utilization efficiency equal to 64-68% are developed. The principles of designing and the design arrangement of a 300 MW GSTP are developed. The effect of economic parameters (the level and ratio of prices for solid fuel and gas, and capital investments) on the net cost of electric energy is determined. The net cost of electric energy produced by the GSTP is lower than that produced by modern combined-cycle power plants in a wide variation range of these parameters. The components of a high-temperature GSTP the development of which determines the main features of such installations are pointed out: a chamber for combusting natural gas and oxygen in a mixture with steam, a vacuum device for condensing steam with a high content of nondensables, and a control system. The possibility of using domestically available gas turbine technologies for developing the GSTP's intermediate-pressure high-temperature part is pointed out. In regard of its environmental characteristics, the GSTP is more advantageous as compared with modern condensing power plants: it allows a flow of concentrated carbon dioxide to be obtained at its outlet, which can be reclaimed; in addition, this plant requires half as much consumption of fresh water.

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

Steam Reforming of CH4 Using Ni- Substituted Pyrochlore Catalysts

NASA Astrophysics Data System (ADS)

Haynes, Daniel J.

The steam reforming of methane (SMR) continues to remain an important industrial reaction for large-scale production of H2 as well as synthesis gas mixtures which can be used for the production of useful chemicals (e.g. methanol). Although SMR is a rather mature technology, traditional nickel based catalysts used industrially are subjected to severe temperatures and reaction conditions, which lead to irreversible activity loss through sintering, support collapse, and carbon formation. Pyrochlore-based mixed oxide have been identified as refractory materials that can be modified through the substitution of catalytic metals and other promoting species into the structure to mitigate these issues causing deactivation. For this study, a lanthanum zirconate pyrochlore catalyst was substituted with Ni to determine whether the oxide structure could effectively stabilize the activity of the catalytic metal during the SMR. The effect of different variables including calcination temperature, a comparison of a substituted versus supported Ni pyrochlore catalyst, Ni weight loading, and Sr promotion have been evaluated to determine the location of the Ni in the structure, and their effect on catalytic behavior. It was revealed that the effect of calcination temperature on a 6wt% Ni substituted pyrochlore produced by the Pechini method demonstrated very little Ni was soluble in the pyrochlore lattice. It was further revealed that by XRD, TEM, and atom probe tomography that, despite the metal loading, Ni exsolves from the structure upon crystallization of the pyrochlore at 700°C, and forms NiO at the surface and grain boundaries. An additional separate La2ZrNiO6 perovskite phase also began to form at higher temperatures (>800°C). Increasing calcination temperature was found to lead to slight sintering of the NiO at the surface, which made the NiO more reducible. Meanwhile decreasing the Ni weight loading was found to produce a lower reduction temperature due to the presence of

Conversion of mill-scale waste to nanoscale zero valent iron (nZVI) for 'green' hydrogen generation via metal-steam reforming

NASA Astrophysics Data System (ADS)

Kesavan, Sathees Kumar

The Proton Exchange Membrane Fuel Cells (PEMFCs) are the most preferred and efficient energy conversion devices for automotive applications but demand high purity hydrogen which comes at a premium price. The currently pursued hydrogen generation methods suffer from issues such as, low efficiency, high cost, environmental non-benignity, and, in some cases, commercial non-viability. Many of these drawbacks including the CO contamination and, storage and delivery can be overcome by resorting to metal-steam reforming (MSR) using iron from steel industry's mill-scale waste. A novel solution-based room temperature technique using sodium borohydride (NaBH4) as the reducing agent has been developed that produces highly active nanoscale (30-40 nm) iron particles. A slightly modified version of this technique using a surfactant and water oil microemulsion resulted in the formation of 5 nm Fe particles. By using hydrazine (N2H4) as an inexpensive and more stable (compared to NaBH4) reductant, body centered cubic iron particles with edge dimensions ˜5 nm were obtained under mild solvothermal conditions in ethanol. The nanoscale zero valent iron (nZVI) powder showed improved kinetics and greater propensity for hydrogen generation than the coarser microscale iron obtained through traditional reduction techniques. To initiate and sustain the somewhat endothermic MSR process, a solar concentrator consisting of a convex polyacrylic sheet with aluminum reflective coating was fabricated. This unique combination of mill-scale waste as iron source, hydrazine as the reductant, mild process conditions for nZVI generation and solar energy as the impetus for actuating MSR, obviates several drawbacks plaguing the grand scheme of producing, storing and delivering pure and humidified H2 to a PEMFC stack.

Heat exchanger for fuel cell power plant reformer

DOEpatents

Misage, Robert; Scheffler, Glenn W.; Setzer, Herbert J.; Margiott, Paul R.; Parenti, Jr., Edmund K.

1988-01-01

A heat exchanger uses the heat from processed fuel gas from a reformer for a fuel cell to superheat steam, to preheat raw fuel prior to entering the reformer and to heat a water-steam coolant mixture from the fuel cells. The processed fuel gas temperature is thus lowered to a level useful in the fuel cell reaction. The four temperature adjustments are accomplished in a single heat exchanger with only three heat transfer cores. The heat exchanger is preheated by circulating coolant and purge steam from the power section during startup of the latter.

Purifier-integrated methanol reformer for fuel cell vehicles

NASA Astrophysics Data System (ADS)

Han, Jaesung; Kim, Il-soo; Choi, Keun-Sup

We developed a compact, 3-kW, purifier-integrated modular reformer which becomes the building block of full-scale 30-kW or 50-kW methanol fuel processors for fuel cell vehicles. Our proprietary technologies regarding hydrogen purification by composite metal membrane and catalytic combustion by washcoated wire-mesh catalyst were combined with the conventional methanol steam-reforming technology, resulting in higher conversion, excellent quality of product hydrogen, and better thermal efficiency than any other systems using preferential oxidation. In this system, steam reforming, hydrogen purification, and catalytic combustion all take place in a single reactor so that the whole system is compact and easy to operate. Hydrogen from the module is ultrahigh pure (99.9999% or better), hence there is no power degradation of PEMFC stack due to contamination by CO. Also, since only pure hydrogen is supplied to the anode of the PEMFC stack, 100% hydrogen utilization is possible in the stack. The module produces 2.3 Nm 3/h of hydrogen, which is equivalent to 3 kW when PEMFC has 43% efficiency. Thermal efficiency (HHV of product H 2/HHV of MeOH in) of the module is 89% and the power density of the module is 0.77 kW/l. This work was conducted in cooperation with Hyundai Motor Company in the form of a Korean national project. Currently the module is under test with an actual fuel cell stack in order to verify its performance. Sooner or later a full-scale 30-kW system will be constructed by connecting these modules in series and parallel and will serve as the fuel processor for the Korean first fuel cell hybrid vehicle.

Enhanced methane steam reforming activity and electrochemical performance of Ni0.9Fe0.1-supported solid oxide fuel cells with infiltrated Ni-TiO2 particles

PubMed Central

Li, Kai; Jia, Lichao; Wang, Xin; Pu, Jian; Chi, Bo; Li, Jian

2016-01-01

Ni0.9Fe0.1 alloy-supported solid oxide fuel cells with NiTiO3 (NTO) infiltrated into the cell support from 0 to 4 wt.% are prepared and investigated for CH4 steam reforming activity and electrochemical performance. The infiltrated NiTiO3 is reduced to TiO2-supported Ni particles in H2 at 650 °C. The reforming activity of the Ni0.9Fe0.1-support is increased by the presence of the TiO2-supported Ni particles; 3 wt.% is the optimal value of the added NTO, corresponding to the highest reforming activity, resistance to carbon deposition and electrochemical performance of the cell. Fueled wet CH4 at 100 mL min−1, the cell with 3 wt.% of NTO demonstrates a peak power density of 1.20 W cm−2 and a high limiting current density of 2.83 A cm−2 at 650 °C. It performs steadily for 96 h at 0.4 A cm−2 without the presence of deposited carbon in the Ni0.9Fe0.1-support and functional anode. Five polarization processes are identified by deconvoluting and data-fitting the electrochemical impedance spectra of the cells under the testing conditions; and the addition of TiO2-supported Ni particles into the Ni0.9Fe0.1-support reduces the polarization resistance of the processes ascribed to CH4 steam reforming and gas diffusion in the Ni0.9Fe0.1-support and functional anode. PMID:27775092

Solar-Power System Produces High-Pressure Steam

NASA Technical Reports Server (NTRS)

Lansing, F. L.

1985-01-01

Combination of three multistaged solar collectors produces highpressure steam for large-scale continuously operating turbines for generating mechanical or electrical energy. Superheated water vapor drives turbines, attaining an overall system efficiency about 22 percent.

Hydrogen production by reforming of liquid hydrocarbons in a membrane reactor for portable power generation-Experimental studies

NASA Astrophysics Data System (ADS)

Damle, Ashok S.

One of the most promising technologies for lightweight, compact, portable power generation is proton exchange membrane (PEM) fuel cells. PEM fuel cells, however, require a source of pure hydrogen. Steam reforming of hydrocarbons in an integrated membrane reactor has potential to provide pure hydrogen in a compact system. Continuous separation of product hydrogen from the reforming gas mixture is expected to increase the yield of hydrogen significantly as predicted by model simulations. In the laboratory-scale experimental studies reported here steam reforming of liquid hydrocarbon fuels, butane, methanol and Clearlite ® was conducted to produce pure hydrogen in a single step membrane reformer using commercially available Pd-Ag foil membranes and reforming/WGS catalysts. All of the experimental results demonstrated increase in hydrocarbon conversion due to hydrogen separation when compared with the hydrocarbon conversion without any hydrogen separation. Increase in hydrogen recovery was also shown to result in corresponding increase in hydrocarbon conversion in these studies demonstrating the basic concept. The experiments also provided insight into the effect of individual variables such as pressure, temperature, gas space velocity, and steam to carbon ratio. Steam reforming of butane was found to be limited by reaction kinetics for the experimental conditions used: catalysts used, average gas space velocity, and the reactor characteristics of surface area to volume ratio. Steam reforming of methanol in the presence of only WGS catalyst on the other hand indicated that the membrane reactor performance was limited by membrane permeation, especially at lower temperatures and lower feed pressures due to slower reconstitution of CO and H 2 into methane thus maintaining high hydrogen partial pressures in the reacting gas mixture. The limited amount of data collected with steam reforming of Clearlite ® indicated very good match between theoretical predictions and

Super-hydrophilic copper sulfide films as light absorbers for efficient solar steam generation under one sun illumination

NASA Astrophysics Data System (ADS)

Guo, Zhenzhen; Ming, Xin; Wang, Gang; Hou, Baofei; Liu, Xinghang; Mei, Tao; Li, Jinhua; Wang, Jianying; Wang, Xianbao

2018-02-01

Solar steam technology is one of the simplest, most direct and effective ways to harness solar energy through water evaporation. Here, we report the development using super-hydrophilic copper sulfide (CuS) films with double-layer structures as light absorbers for solar steam generation. In the double-layer structure system, a porous mixed cellulose ester (MCE) membrane is used as a supporting layer, which enables water to get into the CuS light absorbers through a capillary action to provide continuous water during solar steam generation. The super-hydrophilic property of the double-layer system (CuS/MCE) leads to a thinner water film close to the air-water interface where the surface temperature is sufficiently high, leading to more efficient evaporation (˜80 ± 2.5%) under one sun illumination. Furthermore, the evaporation efficiencies still keep a steady value after 15 cycles of testing. The super-hydrophilic CuS film is promising for practical application in water purification and evaporation as a light absorption material.

The impact of healthcare reform on the efficiency of public county hospitals in China.

PubMed

Jiang, Shuai; Min, Rui; Fang, Peng-Qian

2017-12-20

The new round of Healthcare Reform in China has implemented over 3 years since 2009, and promoted greatly the development of public county hospitals. The purpose of this study is to evaluate county hospitals efficiency before and after the healthcare reform, and further assess the reform effectiveness through the comparative analysis of the efficiency. Data envelopment analysis (DEA) was employed to calculate the efficiency of 1105 sample hospitals which were selected from 31 provinces of China, also, Tobit regression was used to regress against those main external environmental factors. Our results show that the scales and amounts of service of hospitals had increased sharply, however, the efficiency was relatively low and decreased slightly from 2008 to 2012. Thirteen (1.18%) in 2008 and six (0.54%) hospitals in 2012 were defined as technically efficient, and the average scores were 0.2916 and 0.2503. The technical efficiency average score of the post-reform was significantly less than that of the pre-reform (p < 0.001), and the score of eastern region was highest and the western was lowest among three regions of China. It suggests the reform had not well improved county hospital efficiency although hospitals have reached a fair developing scale, and the corresponding policies and measures should be put into effect for improving efficiency, especially in the level and structure of health investment, operation and supervision mechanism of county hospitals.

Efficiency of a solid polymer fuel cell operating on ethanol

NASA Astrophysics Data System (ADS)

Ioannides, Theophilos; Neophytides, Stylianos

The efficiency of a solid polymer fuel cell (SPFC) system operating on ethanol fuel has been analyzed as a function of operating parameters focusing on vehicle and stationary applications. Two types of ethanol processors — employing either steam reforming or partial oxidation (POX) steps — have been considered and their performance has been investigated by thermodynamic analysis. SPFC operation has been analyzed by an available parametric model. It has been found that dilute ethanol-water mixtures (˜55% v/v EtOH) are the most suitable for stationary applications with a steam reformer (SR)-SPFC system. Regarding vehicle applications, pure ethanol (˜95% v/v EtOH) appears to be the best fuel with a POX-SPFC system. Efficiencies in the case of an ideal ethanol processor can be of the order of 60% under low load conditions and 30-35% at peak power, while efficiencies with an actual processor are 80-85% of the above values.

Steam reforming catalyst

DOEpatents

Kramarz, Kurt W.; Bloom, Ira D.; Kumar, Romesh; Ahmed, Shabbir; Wilkenhoener, Rolf; Krumpelt, Michael

2001-01-01

A method of forming a hydrogen rich gas from a source of hydrocarbon fuel. A vapor of the hydrocarbon fuel and steam is brought in contact with a two-part catalyst having a dehydrogenation powder portion and an oxide-ion conducting powder portion at a temperature not less than about 770.degree.C. for a time sufficient to generate the hydrogen rich. The H.sub.2 content of the hydrogen gas is greater than about 70 percent by volume. The dehydrogenation portion of the catalyst includes a group VIII metal, and the oxide-ion conducting portion is selected from a ceramic oxide from the group crystallizing in the fluorite or perovskite structure and mixtures thereof. The oxide-ion conducting portion of the catalyst is a ceramic powder of one or more of ZrO.sub.2, CeO.sub.2, Bi.sub.2 O.sub.3, (BiVO).sub.4, and LaGaO.sub.3.

Thermal analysis of heat and power plant with high temperature reactor and intermediate steam cycle

NASA Astrophysics Data System (ADS)

Fic, Adam; Składzień, Jan; Gabriel, Michał

2015-03-01

Thermal analysis of a heat and power plant with a high temperature gas cooled nuclear reactor is presented. The main aim of the considered system is to supply a technological process with the heat at suitably high temperature level. The considered unit is also used to produce electricity. The high temperature helium cooled nuclear reactor is the primary heat source in the system, which consists of: the reactor cooling cycle, the steam cycle and the gas heat pump cycle. Helium used as a carrier in the first cycle (classic Brayton cycle), which includes the reactor, delivers heat in a steam generator to produce superheated steam with required parameters of the intermediate cycle. The intermediate cycle is provided to transport energy from the reactor installation to the process installation requiring a high temperature heat. The distance between reactor and the process installation is assumed short and negligable, or alternatively equal to 1 km in the analysis. The system is also equipped with a high temperature argon heat pump to obtain the temperature level of a heat carrier required by a high temperature process. Thus, the steam of the intermediate cycle supplies a lower heat exchanger of the heat pump, a process heat exchanger at the medium temperature level and a classical steam turbine system (Rankine cycle). The main purpose of the research was to evaluate the effectiveness of the system considered and to assess whether such a three cycle cogeneration system is reasonable. Multivariant calculations have been carried out employing the developed mathematical model. The results have been presented in a form of the energy efficiency and exergy efficiency of the system as a function of the temperature drop in the high temperature process heat exchanger and the reactor pressure.

Comparison of Iron and Tungsten Based Oxygen Carriers for Hydrogen Production Using Chemical Looping Reforming

NASA Astrophysics Data System (ADS)

Khan, M. N.; Shamim, T.

2017-08-01

Hydrogen production by using a three reactor chemical looping reforming (TRCLR) technology is an innovative and attractive process. Fossil fuels such as methane are the feedstocks used. This process is similar to a conventional steam-methane reforming but occurs in three steps utilizing an oxygen carrier. As the oxygen carrier plays an important role, its selection should be done carefully. In this study, two oxygen carrier materials of base metal iron (Fe) and tungsten (W) are analysed using a thermodynamic model of a three reactor chemical looping reforming plant in Aspen plus. The results indicate that iron oxide has moderate oxygen carrying capacity and is cheaper since it is abundantly available. In terms of hydrogen production efficiency, tungsten oxide gives 4% better efficiency than iron oxide. While in terms of electrical power efficiency, iron oxide gives 4.6% better results than tungsten oxide. Overall, a TRCLR system with iron oxide is 2.6% more efficient and is cost effective than the TRCLR system with tungsten oxide.

A 400-kWe high-efficiency steam turbine for industrial cogeneration

NASA Technical Reports Server (NTRS)

Leibowitz, H. M.

1982-01-01

An advanced state-of-the-art steam turbine-generator developed to serve as the power conversion subsystem for the Department of Energy's Sandia National Laboratories' Solar Total-Energy Project (STEP) is described. The turbine-generator, which is designed to provide 400-kW of net electrical power, represents the largest turbine-generator built specifically for commercial solar-powered cogeneration. The controls for the turbine-generator incorporate a multiple, partial-arc entry to provide efficient off-design performance, as well as an extraction control scheme to permit extraction flow regulation while maintaining 110-spsig pressure. Normal turbine operation is achieved while synchronized to a local utility and in a stand-alone mode. In both cases, the turbine-generator features automatic load control as well as remote start-up and shutdown capability. Tests totaling 200 hours were conducted to confirm the integrity of the turbine's mechanical structure and control function. Performance tests resulted in a measured inlet throttle flow of 8,450 pounds per hour, which was near design conditions.

Increasing the electric efficiency of a fuel cell system by recirculating the anodic offgas

NASA Astrophysics Data System (ADS)

Heinzel, A.; Roes, J.; Brandt, H.

The University of Duisburg-Essen and the Center for Fuel Cell Technology (ZBT Duisburg GmbH) have developed a compact multi-fuel steam reformer suitable for natural gas, propane and butane. Fuel processor prototypes based on this concept were built up in the power range from 2.5 to 12.5 kW thermal hydrogen power for different applications and different industrial partners. The fuel processor concept contains all the necessary elements, a prereformer step, a primary reformer, water gas shift reactors, a steam generator, internal heat exchangers, in order to achieve an optimised heat integration and an external burner for heat supply as well as a preferential oxidation step (PrOx) as CO purification. One of the built fuel processors is designed to deliver a thermal hydrogen power output of 2.5 kW according to a PEM fuel cell stack providing about 1 kW electrical power and achieves a thermal efficiency of about 75% (LHV basis after PrOx), while the CO content of the product gas is below 20 ppm. This steam reformer has been combined with a 1 kW PEM fuel cell. Recirculating the anodic offgas results in a significant efficiency increase for the fuel processor. The gross efficiency of the combined system was already clearly above 30% during the first tests. Further improvements are currently investigated and developed at the ZBT.

Self-sustained operation of a kW e-class kerosene-reforming processor for solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Yoon, Sangho; Bae, Joongmyeon; Kim, Sunyoung; Yoo, Young-Sung

In this paper, fuel-processing technologies are developed for application in residential power generation (RPG) in solid oxide fuel cells (SOFCs). Kerosene is selected as the fuel because of its high hydrogen density and because of the established infrastructure that already exists in South Korea. A kerosene fuel processor with two different reaction stages, autothermal reforming (ATR) and adsorptive desulfurization reactions, is developed for SOFC operations. ATR is suited to the reforming of liquid hydrocarbon fuels because oxygen-aided reactions can break the aromatics in the fuel and steam can suppress carbon deposition during the reforming reaction. ATR can also be implemented as a self-sustaining reactor due to the exothermicity of the reaction. The kW e self-sustained kerosene fuel processor, including the desulfurizer, operates for about 250 h in this study. This fuel processor does not require a heat exchanger between the ATR reactor and the desulfurizer or electric equipment for heat supply and fuel or water vaporization because a suitable temperature of the ATR reformate is reached for H 2S adsorption on the ZnO catalyst beds in desulfurizer. Although the CH 4 concentration in the reformate gas of the fuel processor is higher due to the lower temperature of ATR tail gas, SOFCs can directly use CH 4 as a fuel with the addition of sufficient steam feeds (H 2O/CH 4 ≥ 1.5), in contrast to low-temperature fuel cells. The reforming efficiency of the fuel processor is about 60%, and the desulfurizer removed H 2S to a sufficient level to allow for the operation of SOFCs.

Reforms: a quest for efficiency or an opportunity for vested interests'? A case study of pharmaceutical policy reforms in Tanzania.

PubMed

Mori, Amani Thomas; Kaale, Eliangiringa Amos; Risha, Peter

2013-07-13

Regulation of the pharmaceutical sector is a challenging task for most governments in the developing countries. In Tanzania, this task falls under the Food and Drugs Authority and the Pharmacy Council. In 2010, the Pharmacy Council spearheaded policy reforms in the pharmaceutical sector aimed at taking over the control of the regulation of the business of pharmacy from the Tanzania Food and Drugs Authority. This study provides a critical analysis of these reforms. The study employed a qualitative case-study design. Data was collected through in-depth interviews, focus group discussions and document reviews. Data was analyzed thematically using a policy triangle framework. The analysis was done manually. The reforms adopted an incremental model of public policy-making and the process was characterized by lobbying for political support, negotiations and bargaining between the interest groups. These negotiations were largely centred on vested interests and not on the impact of the reforms on the efficiency of pharmaceutical regulations in the country. Stakeholders from the micro and meso levels were minimally involved in the policy reforms. Recent pharmaceutical regulation reforms in Tanzania were overshadowed by vested interests, displacing a critical analysis of optimal policy options that have the potential to increase efficiency in the regulation of the business of pharmacy. Politics influenced decision-making at different levels of the reform process.

Comparison of steam sterilization conditions efficiency in the treatment of Infectious Health Care Waste.

PubMed

Maamari, Olivia; Mouaffak, Lara; Kamel, Ramza; Brandam, Cedric; Lteif, Roger; Salameh, Dominique

2016-03-01

Many studies show that the treatment of Infectious Health Care Waste (IHCW) in steam sterilization devices at usual operating standards does not allow for proper treatment of Infectious Health Care Waste (IHCW). Including a grinding component before sterilization allows better waste sterilization, but any hard metal object in the waste can damage the shredder. The first objective of the study is to verify that efficient IHCW treatment can occur at standard operating parameters defined by the contact time-temperature couple in steam treatment systems without a pre-mixing/fragmenting or pre-shredding step. The second objective is to establish scientifically whether the standard operation conditions for a steam treatment system including a step of pre-mixing/fragmenting were sufficient to destroy the bacterial spores in IHCW known to be the most difficult to treat. Results show that for efficient sterilization of dialysis cartridges in a pilot 60L steam treatment system, the process would require more than 20 min at 144°C without a pre-mixing/fragmenting step. In a 720L steam treatment system including pre-mixing/fragmenting paddles, only 10 min at 144°C are required to sterilize IHCW proved to be sterilization challenges such as dialysis cartridges and diapers in normal conditions of rolling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Catalytic Exhaust Gas Recirculation-Loop Reforming for High Efficiency in a Stoichiometric Spark-Ignited Engine through Thermochemical Recuperation and Dilution Limit Extension, Part 2: Engine Performance

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

Chang, Yan; Szybist, James P.; Pihl, Josh A.

This is the second part of a two-part investigation of on-board catalytic fuel reforming to increase the brake efficiency of a multicylinder, stoichiometric spark-ignited (SI) engine. In Part 1 of the investigation, we analytically and experimentally characterized the energetics and kinetics of a candidate reforming catalyst over a range of reforming equivalence ratios and oxygen concentration conditions to identify the best conditions for efficient reforming. In the present part of our investigation, we studied an engine strategy that combined exhaust gas recirculation (EGR)–loop reforming with dilution limit extension of the combustion. In our experiments, we found that, under an enginemore » operating condition of 2000 rpm and brake mean effective pressure (4 bar), catalytic EGR reforming made it possible to sustain stable combustion with a volumetric equivalent of 45%–55% EGR. Under this same operating condition with stoichiometric engine exhaust (and no reforming), we were only able to sustain stable combustion with EGR under 25%. In conclusion, these results indicate that multicylinder gasoline engine efficiency can be increased substantially with catalytic reforming combined with and higher EGR operation, resulting in a decrease of more than 8% in fuel consumption, compared to baseline operation.« less

Catalytic Exhaust Gas Recirculation-Loop Reforming for High Efficiency in a Stoichiometric Spark-Ignited Engine through Thermochemical Recuperation and Dilution Limit Extension, Part 2: Engine Performance

DOE PAGES

Chang, Yan; Szybist, James P.; Pihl, Josh A.; ...

2018-01-17

This is the second part of a two-part investigation of on-board catalytic fuel reforming to increase the brake efficiency of a multicylinder, stoichiometric spark-ignited (SI) engine. In Part 1 of the investigation, we analytically and experimentally characterized the energetics and kinetics of a candidate reforming catalyst over a range of reforming equivalence ratios and oxygen concentration conditions to identify the best conditions for efficient reforming. In the present part of our investigation, we studied an engine strategy that combined exhaust gas recirculation (EGR)–loop reforming with dilution limit extension of the combustion. In our experiments, we found that, under an enginemore » operating condition of 2000 rpm and brake mean effective pressure (4 bar), catalytic EGR reforming made it possible to sustain stable combustion with a volumetric equivalent of 45%–55% EGR. Under this same operating condition with stoichiometric engine exhaust (and no reforming), we were only able to sustain stable combustion with EGR under 25%. In conclusion, these results indicate that multicylinder gasoline engine efficiency can be increased substantially with catalytic reforming combined with and higher EGR operation, resulting in a decrease of more than 8% in fuel consumption, compared to baseline operation.« less

Development of a Highly Loaded Rotor Blade for Steam Turbines

NASA Astrophysics Data System (ADS)

Segawa, Kiyoshi; Shikano, Yoshio; Tsubouchi, Kuniyoshi; Shibashita, Naoaki

Turbine manufacturers have been concerned about efficient utilization of limited energy resources and prevention of environmental pollution. For steam turbine power plants, a higher efficiency gain is necessary to reduce the fuel consumption rate. Blade configurations have been studied for reductions of profile loss and endwall loss that lead to decreased steam turbine internal efficiency, by applying recent aerodynamic technologies based on advanced numerical analysis methods. This paper discusses increase of pitch-chord ratio by 14% (reduction of rotor blade numbers by 14%) and increased blade aerodynamic loading without deterioration of performance. A new rotor cascade is found which improves blade performance, especially at the root section where the reduction in the energy loss coefficient is about 40%. This rotor blade also provides lower manufacturing cost.

Strategies for improving the performance and stability of Ni-based catalysts for reforming reactions.

PubMed

Li, Shuirong; Gong, Jinlong

2014-11-07

Owing to the considerable publicity that has been given to petroleum related economic, environmental, and political problems, renewed attention has been focused on the development of highly efficient and stable catalytic materials for the production of chemical/fuel from renewable resources. Supported nickel nanoclusters are widely used for catalytic reforming reactions, which are key processes for generating synthetic gas and/or hydrogen. New challenges were brought out by the extension of feedstock from hydrocarbons to oxygenates derivable from biomass, which could minimize the environmental impact of carbonaceous fuels and allow a smooth transition from fossil fuels to a sustainable energy economy. This tutorial review describes the recent efforts made toward the development of nickel-based catalysts for the production of hydrogen from oxygenated hydrocarbons via steam reforming reactions. In general, three challenges facing the design of Ni catalysts should be addressed. Nickel nanoclusters are apt to sinter under catalytic reforming conditions of high temperatures and in the presence of steam. Severe carbon deposition could also be observed on the catalyst if the surface carbon species adsorbed on metal surface are not removed in time. Additionally, the production of hydrogen rich gas with a low concentration of CO is a challenge using nickel catalysts, which are not so active in the water gas shift reaction. Accordingly, three strategies were presented to address these challenges. First, the methodologies for the preparation of highly dispersed nickel catalysts with strong metal-support interaction were discussed. A second approach-the promotion in the mobility of the surface oxygen-is favored for the yield of desired products while promoting the removal of surface carbon deposition. Finally, the process intensification via the in situ absorption of CO2 could produce a hydrogen rich gas with low CO concentration. These approaches could also guide the design

Performance of equipment used in high-pressure steam floods

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

Owens, M.E.; Bramley, B.G.

1966-01-01

Recovery of low-gravity, high-viscosity crude oil from relatively shallow reservoirs is becoming feasible through the application of steam flooding. Pan American Petroleum Corp. initiated a pilot steam flood with a 5.36 million btu/hr, 1,500-psi steam generator at the Winkleman Dome Field in West Central Wyoming in March, 1964. After 1 yr of operation, this steamer was replaced with a larger unit capable of 12 million-btu/hr, 2,500-psi steam generators, one at the Salt Creek Shannon Field and another at the Fourbear Field, both in Wyoming. This paper discusses the equipment used in high-pressure steam flooding and reviews some of the problemsmore » that have been encountered in the application of the equipment. Where determined, a suggested solution is presented.« less

Effects of Fuel Cell Anode Recycle on Catalytic Fuel Reforming

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

Shekhawat, Dushyant; Berry, D.A.; Gardner, T.H.

2007-06-01

The presence of steam in the reactant gas of a catalytic fuel reformer decreases the formation of carbon, minimizing catalyst deactivation. However, the operation of the reformer without supplemental water reduces the size, weight, cost, and overall complexity of the system. The work presented here examines experimentally two options for adding steam to the reformer inlet: (I) recycle of a simulated fuel cell anode exit gas (comprised of mainly CO2, H2O, and N2 and some H2 and CO) and (II) recycle of the reformate from the reformer exit back to the reformer inlet (mainly comprised of H2, CO, and N2more » and some H2O and CO2). As expected, anode gas recycle reduced the carbon formation and increased the hydrogen concentration in the reformate. However, reformer recycle was not as effective due principally to the lower water content in the reformate compared to the anode gas. In fact, reformate recycle showed slightly increased carbon formation compared to no recycle. In an attempt to understand the effects of individual gases in these recycle streams (H2, CO, CO2, N2, and H2O), individual gas species were independently introduced to the reformer feed.« less

Effects of fuel cell anode recycle on catalytic fuel reforming

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

shekhawat, D.; Berry, D.; Gardner, T.

2007-01-01

The presence of steam in the reactant gas of a catalytic fuel reformer decreases the formation of carbon, minimizing catalyst deactivation. However, the operation of the reformer without supplemental water reduces the size, weight, cost, and overall complexity of the system. The work presented here examines experimentally two options for adding steam to the reformer inlet: (I) recycle of a simulated fuel cell anode exit gas (comprised of mainly CO2, H2O, and N2 and some H2 and CO) and (II) recycle of the reformate from the reformer exit back to the reformer inlet (mainly comprised of H2, CO, and N2more » and some H2O and CO2). As expected, anode gas recycle reduced the carbon formation and increased the hydrogen concentration in the reformate. However, reformer recycle was not as effective due principally to the lower water content in the reformate compared to the anode gas. In fact, reformate recycle showed slightly increased carbon formation compared to no recycle. In an attempt to understand the effects of individual gases in these recycle streams (H2, CO, CO2, N2, and H2O), individual gas species were independently introduced to the reformer feed. Published by Elsevier B.V.« less

Spontaneous Synthesis of Highly Crystalline TiO2 Compact/Mesoporous Stacked Films by a Low-Temperature Steam-Annealing Method for Efficient Perovskite Solar Cells.

PubMed

Sanehira, Yoshitaka; Numata, Youhei; Ikegami, Masashi; Miyasaka, Tsutomu

2018-05-23

Highly crystalline TiO 2 nanostructured films were synthesized by a simple steam treatment of a TiCl 4 precursor film under a saturated water vapor atmosphere at 125 °C, here referred to as the steam-annealing method. In a single TiO 2 film preparation step, a bilayer structure comprising a compact bottom layer and a mesoporous surface layer was formed. The mesoporous layer was occupied by bipyramidal nanoparticles, with a composite phase of anatase and brookite crystals. Despite the low-temperature treatment process, the crystallinity of the TiO 2 film was high, comparable with that of the TiO 2 film sintered at 500 °C. The compact double-layered TiO 2 film was applied to perovskite solar cells (PSCs) as an electron-collecting layer. The PSC exhibited a maximum power conversion efficiency (PCE) of 18.9% with an open-circuit voltage ( V OC ) of 1.15 V. The PCE and V OC were higher than those of PSCs using a TiO 2 film formed by 500 °C sintering.

Comparative evaluation of surface and downhole steam-generation techniques

NASA Astrophysics Data System (ADS)

Hart, C.

The application of heat to reservoirs containing high API gravity oils can substantially improve recovery. Although steam injection is currently the principal thermal recovery method, heat transmission losses associated with delivery of the steam from the surface generators to the oil bearing formation has limited conventional steam injection to shallow reservoirs. The objective of the Department of Energy's Project DEEP STEAM is to develop the technology required to economically produce heavy oil from deep reservoirs. The tasks included in this effort are the development and evaluation of thermally efficient delivery systems and downhole steam generation systems. The technical and economic performance of conventional surface steam drives, which are strongly influenced by heat losses are compared. The selection of a preferred technology based upon either total efficiency or cost is found to be strongly influenced by reservoir depth, steam mass flow rate, and sandface steam quality.

Pilot scale high solids anaerobic digestion of steam autoclaved municipal solid waste (MSW) pulp

USDA-ARS?s Scientific Manuscript database

Steam autoclaving is an efficient method for the separation and recovery of nearly all organics from MSW, yet a reliable alternative outlet for the large volume of organics produced has not yet been successfully demonstrated. The material produced by the autoclave contains a high concentration of s...

Steam reforming of fast pyrolysis-derived aqueous phase oxygenates over Co, Ni, and Rh metals supported on MgAl 2O 4

DOE PAGES

Xing, Rong; Dagle, Vanessa Lebarbier; Flake, Matthew; ...

2016-02-03

In this paper we examine the feasibility of steam reforming the mixed oxygenate aqueous fraction derived from fast pyrolysis bio-oils. Catalysts selective towards hydrogen formation and resistant to carbon formation utilizing feeds with relatively low steam-to-carbon (S/C) ratios are desired. Rh (5 wt%), Pt (5 wt%), Ru (5 wt%), Ir (5 wt%), Ni (15 wt%), and Co (15 wt%) metals supported on MgAl2O4 were evaluated for catalytic performance at 500 °C and 1 atm using a complex feed mixture comprising acids, polyols, cycloalkanes, and phenolic compounds. The Rh catalyst was found to be the most active and resistant to carbonmore » formation. The Ni and Co catalysts were found to be more active than the other noble metal catalysts investigated (Pt, Ru, and Ir).« less

Studies of the use of high-temperature nuclear heat from an HTGR for hydrogen production

NASA Technical Reports Server (NTRS)

Peterman, D. D.; Fontaine, R. W.; Quade, R. N.; Halvers, L. J.; Jahromi, A. M.

1975-01-01

The results of a study which surveyed various methods of hydrogen production using nuclear and fossil energy are presented. A description of these methods is provided, and efficiencies are calculated for each case. The process designs of systems that utilize the heat from a general atomic high temperature gas cooled reactor with a steam methane reformer and feed the reformer with substitute natural gas manufactured from coal, using reforming temperatures, are presented. The capital costs for these systems and the resultant hydrogen production price for these cases are discussed along with a research and development program.

Challenges and Strength of Current Industrial Energy Efficiency Management Practices in Steam Industries

NASA Astrophysics Data System (ADS)

Nkosi, S. B.; Pretorius, J. H. C.

2017-07-01

The aim of this study is to achieve greater output by examining the existing way of coordinating the determined attempts of Steam Industries in South Africa to successfully reach a sustainable industrial development by using energy source adequately in a more competent way. Furthermore into the study we look at obstacles that prevent and those that leads to maximum utilization of energy management measures and also highlights the effects of implementing cheap available energy source in South Africa. The investigation and analysis have shown that energy is not well managed in Steam Industries and that the use of energy is minimized and not fully utilized due to poor management and lack of knowledge. Another detection was that lack of government structured and strategic measures of implementing and motivating the use of energy effectively. The effective and rational use of available power by Steam Industries in South Africa is a key player in developing a sustainable industrial development. The use of energy efficiency management strategies has contributed an increase in economic and improve environmentally friendly in the industrial sector. The slow pace adoption of energy saving and cost effective management programmes are negatively impacting on the benefits to Steam Industries in South Africa. In conclusion the study finds that the economy can be boosted by implementing energy efficiency management programmes and environmentally friendly. These will also stabilize the negative impact of energy raising prices.

Glycerol Production and Transformation: A Critical Review with Particular Emphasis on Glycerol Reforming Reaction for Producing Hydrogen in Conventional and Membrane Reactors.

PubMed

Bagnato, Giuseppe; Iulianelli, Adolfo; Sanna, Aimaro; Basile, Angelo

2017-03-23

Glycerol represents an emerging renewable bio-derived feedstock, which could be used as a source for producing hydrogen through steam reforming reaction. In this review, the state-of-the-art about glycerol production processes is reviewed, with particular focus on glycerol reforming reactions and on the main catalysts under development. Furthermore, the use of membrane catalytic reactors instead of conventional reactors for steam reforming is discussed. Finally, the review describes the utilization of the Pd-based membrane reactor technology, pointing out the ability of these alternative fuel processors to simultaneously extract high purity hydrogen and enhance the whole performances of the reaction system in terms of glycerol conversion and hydrogen yield.

ELECTROCHEMISTRY AND ON-CELL REFORMATION MODELING FOR SOLID OXIDE FUEL CELL STACKS

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

Recknagle, Kurtis P.; Jarboe, Daniel T.; Johnson, Kenneth I.

2007-01-16

ABSTRACT Providing adequate and efficient cooling schemes for solid-oxide-fuel-cell (SOFC) stacks continues to be a challenge coincident with the development of larger, more powerful stacks. The endothermic steam-methane reformation reaction can provide cooling and improved system efficiency when performed directly on the electrochemically active anode. Rapid kinetics of the endothermic reaction typically causes a localized temperature depression on the anode near the fuel inlet. It is desirable to extend the endothermic effect over more of the cell area and mitigate the associated differences in temperature on the cell to alleviate subsequent thermal stresses. In this study, modeling tools validated formore » the prediction of fuel use, on-cell methane reforming, and the distribution of temperature within SOFC stacks, are employed to provide direction for modifying the catalytic activity of anode materials to control the methane conversion rate. Improvements in thermal management that can be achieved through on-cell reforming is predicted and discussed. Two operating scenarios are considered: one in which the methane fuel is fully pre-reformed, and another in which a substantial percentage of the methane is reformed on-cell. For the latter, a range of catalytic activity is considered and the predicted thermal effects on the cell are presented. Simulations of the cell electrochemical and thermal performance with and without on-cell reforming, including structural analyses, show a substantial decrease in thermal stresses for an on-cell reforming case with slowed methane conversion.« less

Hydrogen Production by Steam Reforming of Ethanol over Nickel Catalysts Supported on Sol Gel Made Alumina: Influence of Calcination Temperature on Supports

PubMed Central

Yaakob, Zahira; Bshish, Ahmed; Ebshish, Ali; Tasirin, Siti Masrinda; Alhasan, Fatah H.

2013-01-01

Selecting a proper support in the catalyst system plays an important role in hydrogen production via ethanol steam reforming. In this study, sol gel made alumina supports prepared for nickel (Ni) catalysts were calcined at different temperatures. A series of (Ni/AlS.G.) catalysts were synthesized by an impregnation procedure. The influence of varying the calcination temperature of the sol gel made supports on catalyst activity was tested in ethanol reforming reaction. The characteristics of the sol gel alumina supports and Ni catalysts were affected by the calcination temperature of the supports. The structure of the sol gel made alumina supports was transformed in the order of γ → (γ + θ) → θ-alumina as the calcination temperature of the supports increased from 600 °C to 1000 °C. Both hydrogen yield and ethanol conversion presented a volcano-shaped behavior with maximum values of 4.3 mol/mol ethanol fed and 99.5%, respectively. The optimum values were exhibited over Ni/AlS.G800 (Ni catalyst supported on sol gel made alumina calcined at 800 °C). The high performance of the Ni/AlS.G800 catalyst may be attributed to the strong interaction of Ni species and sol gel made alumina which lead to high nickel dispersion and small particle size. PMID:28809270

Hydrogen Production by Steam Reforming of Ethanol over Nickel Catalysts Supported on Sol Gel Made Alumina: Influence of Calcination Temperature on Supports.

PubMed

Yaakob, Zahira; Bshish, Ahmed; Ebshish, Ali; Tasirin, Siti Masrinda; Alhasan, Fatah H

2013-05-30

Selecting a proper support in the catalyst system plays an important role in hydrogen production via ethanol steam reforming. In this study, sol gel made alumina supports prepared for nickel (Ni) catalysts were calcined at different temperatures. A series of (Ni/Al S.G. ) catalysts were synthesized by an impregnation procedure. The influence of varying the calcination temperature of the sol gel made supports on catalyst activity was tested in ethanol reforming reaction. The characteristics of the sol gel alumina supports and Ni catalysts were affected by the calcination temperature of the supports. The structure of the sol gel made alumina supports was transformed in the order of γ → (γ + θ) → θ-alumina as the calcination temperature of the supports increased from 600 °C to 1000 °C. Both hydrogen yield and ethanol conversion presented a volcano-shaped behavior with maximum values of 4.3 mol/mol ethanol fed and 99.5%, respectively. The optimum values were exhibited over Ni/Al S.G800 (Ni catalyst supported on sol gel made alumina calcined at 800 °C). The high performance of the Ni/Al S.G800 catalyst may be attributed to the strong interaction of Ni species and sol gel made alumina which lead to high nickel dispersion and small particle size.

High pressure hydriding of sponge-Zr in steam-hydrogen mixtures

NASA Astrophysics Data System (ADS)

Soo Kim, Yeon; Wang, Wei-E.; Olander, D. R.; Yagnik, S. K.

1997-07-01

Hydriding kinetics of thin sponge-Zr layers metallurgically bonded to a Zircaloy disk has been studied by thermogravimetry in the temperature range 350-400°C in 7 MPa hydrogen-steam mixtures. Some specimens were prefilmed with a thin oxide layer prior to exposure to the reactant gas; all were coated with a thin layer of gold to avoid premature reaction at edges. Two types of hydriding were observed in prefilmed specimens, viz., a slow hydrogen absorption process that precedes an accelerated (massive) hydriding. At 7 MPa total pressure, the critical ratio of H 2/H 2O above which massive hydriding occurs at 400°C is ˜ 200. The critical H 2/H 20 ratio is shifted to ˜2.5 × 103 at 350°C. The slow hydriding process occurs only when conditions for hydriding and oxidation are approximately equally favorable. Based on maximum weight gain, the specimen is completely converted to δ-ZrH 2 by massive hydriding in ˜5 h at a hydriding rate of ˜10 -6 mol H/cm 2 s. Incubation times of 10-20 h prior to the onset of massive hydriding increases with prefilm oxide thickness in the range of 0-10 μm. By changing to a steam-enriched gas, massive hydriding that initially started in a steam-starved condition was arrested by re-formation of a protective oxide scale.

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.

Analysis of the energy efficiency of an integrated ethanol processor for PEM fuel cell systems

NASA Astrophysics Data System (ADS)

Francesconi, Javier A.; Mussati, Miguel C.; Mato, Roberto O.; Aguirre, Pio A.

The aim of this work is to investigate the energy integration and to determine the maximum efficiency of an ethanol processor for hydrogen production and fuel cell operation. Ethanol, which can be produced from renewable feedstocks or agriculture residues, is an attractive option as feed to a fuel processor. The fuel processor investigated is based on steam reforming, followed by high- and low-temperature shift reactors and preferential oxidation, which are coupled to a polymeric fuel cell. Applying simulation techniques and using thermodynamic models the performance of the complete system has been evaluated for a variety of operating conditions and possible reforming reactions pathways. These models involve mass and energy balances, chemical equilibrium and feasible heat transfer conditions (Δ T min). The main operating variables were determined for those conditions. The endothermic nature of the reformer has a significant effect on the overall system efficiency. The highest energy consumption is demanded by the reforming reactor, the evaporator and re-heater operations. To obtain an efficient integration, the heat exchanged between the reformer outgoing streams of higher thermal level (reforming and combustion gases) and the feed stream should be maximized. Another process variable that affects the process efficiency is the water-to-fuel ratio fed to the reformer. Large amounts of water involve large heat exchangers and the associated heat losses. A net electric efficiency around 35% was calculated based on the ethanol HHV. The responsibilities for the remaining 65% are: dissipation as heat in the PEMFC cooling system (38%), energy in the flue gases (10%) and irreversibilities in compression and expansion of gases. In addition, it has been possible to determine the self-sufficient limit conditions, and to analyze the effect on the net efficiency of the input temperatures of the clean-up system reactors, combustion preheating, expander unit and crude ethanol as

How different are hospitals' responses to a financial reform? The impact on efficiency of activity-based financing.

PubMed

Biørn, Erik; Hagen, Terje P; Iversen, Tor; Magnussen, Jon

2010-03-01

For policy-makers the heterogeneity of hospital response to reforms is of crucial concern. Even though a reform may entail a positive effect on average efficiency, policy-makers will consider the reform as less attractive if the variation in hospital efficiency increases. The reason is that increased variance of efficiency across hospitals is likely to increase the impact of geography on access to hospital services. This paper examines the heterogeneity with respect to the impact of a financial reform-Activity Based Financing (ABF)-on hospital efficiency in Norway. From a theoretical model we find an ambiguous effect of hospital heterogeneity on the effect of ABF on efficiency. The data set is from a contiguous 10-year panel of 47 hospitals covering both pre-ABF years and years after its imposition. Substantial heterogeneity in the responses, as measured by both estimated and predicted coefficients, is found. We did not find any significant correlation between pre-ABF measures of efficiency and the effect of ABF on efficiency. We did however find a strongly significant correlation between the effect of ABF and post-ABF efficiency. Thus, the analysis confirms the impression that, whereas pre-ABF efficiency did not play any role in how hospitals responded to ABF, those responding generally ended up as better-performing hospitals. Hence, for the type of reform studied in this article we find that policy-makers do not need to worry about the impact of location on patients' access to hospital services.

Glycerol Production and Transformation: A Critical Review with Particular Emphasis on Glycerol Reforming Reaction for Producing Hydrogen in Conventional and Membrane Reactors

PubMed Central

Bagnato, Giuseppe; Iulianelli, Adolfo; Sanna, Aimaro; Basile, Angelo

2017-01-01

Glycerol represents an emerging renewable bio-derived feedstock, which could be used as a source for producing hydrogen through steam reforming reaction. In this review, the state-of-the-art about glycerol production processes is reviewed, with particular focus on glycerol reforming reactions and on the main catalysts under development. Furthermore, the use of membrane catalytic reactors instead of conventional reactors for steam reforming is discussed. Finally, the review describes the utilization of the Pd-based membrane reactor technology, pointing out the ability of these alternative fuel processors to simultaneously extract high purity hydrogen and enhance the whole performances of the reaction system in terms of glycerol conversion and hydrogen yield. PMID:28333121

Investigation of the promoting effect of Mn on a Pt/C catalyst for the steam and aqueous phase reforming of glycerol

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

Bossola, Filippo; Pereira-Hernández, Xavier Isidro; Evangelisti, Claudio

2017-05-01

The catalytic performances in steam reforming (SR) and aqueous phase reforming (APR) of glycerol of a bimetallic Pt-Mn catalyst supported on activated carbon are investigated and correlated with the surface properties of the catalyst. Under SR conditions, Mn showed a significant promoting effect over Pt/C, both in terms of hydrogen production rate and conversion, with a higher selectivity toward the glycerol dehydration products. Upon addition of Mn the amount of strong Lewis acid sites increased, promoting the dehydration of glycerol and favoring the CAO over CAC cleavage at expenses of hydrogen selectivity. Conversely, under APR conditions, a slightly higher hydrogenmore » selectivity and only minimal enhancement in hydrogen production were found, while the products selectivity was comparable to Pt/C. Most of Mn leached into the aqueous media, but the remaining (<5% of the fresh parent sample) might be alloyed with Pt and promote the CO desorption from neighbor Pt sites.« less

Influence of high-temperature steam on the reactivity of CaO sorbent for CO₂ capture.

PubMed

Donat, Felix; Florin, Nicholas H; Anthony, Edward J; Fennell, Paul S

2012-01-17

Calcium looping is a high-temperature CO(2) capture technology applicable to the postcombustion capture of CO(2) from power station flue gas, or integrated with fuel conversion in precombustion CO(2) capture schemes. The capture technology uses solid CaO sorbent derived from natural limestone and takes advantage of the reversible reaction between CaO and CO(2) to form CaCO(3); that is, to achieve the separation of CO(2) from flue or fuel gas, and produce a pure stream of CO(2) suitable for geological storage. An important characteristic of the sorbent, affecting the cost-efficiency of this technology, is the decay in reactivity of the sorbent over multiple CO(2) capture-and-release cycles. This work reports on the influence of high-temperature steam, which will be present in flue (about 5-10%) and fuel (∼20%) gases, on the reactivity of CaO sorbent derived from four natural limestones. A significant increase in the reactivity of these sorbents was found for 30 cycles in the presence of steam (from 1-20%). Steam influences the sorbent reactivity in two ways. Steam present during calcination promotes sintering that produces a sorbent morphology with most of the pore volume associated with larger pores of ∼50 nm in diameter, and which appears to be relatively more stable than the pore structure that evolves when no steam is present. The presence of steam during carbonation reduces the diffusion resistance during carbonation. We observed a synergistic effect, i.e., the highest reactivity was observed when steam was present for both calcination and carbonation.

Steam reforming of fuel to hydrogen in fuel cell

DOEpatents

Young, J.E.; Fraioli, A.V.

1983-07-13

A fuel cell is described capable of utilizing a hydrocarbon such as methane as fuel and having an internal dual catalyst system within the anode zone, the dual catalyst system including an anode catalyst supporting and in heat conducting relationship with a reforming catalyst with heat for the reforming reaction being supplied by the reaction at the anode catalyst.

Steam reforming of fuel to hydrogen in fuel cells

DOEpatents

Fraioli, Anthony V.; Young, John E.

1984-01-01

A fuel cell capable of utilizing a hydrocarbon such as methane as fuel and having an internal dual catalyst system within the anode zone, the dual catalyst system including an anode catalyst supporting and in heat conducting relationship with a reforming catalyst with heat for the reforming reaction being supplied by the reaction at the anode catalyst.

Radionuclide and contaminant immobilization in the fluidized bed steam reforming waste products

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

Neeway, James J.; Qafoku, Nikolla; Westsik, Joseph H.

2012-05-01

The goal of this chapter is to introduce the reader to the Fluidized Bed Steam Reforming (FBSR) process and resulting waste form. The first section of the chapter gives an overview of the potential need for FBSR processing in nuclear waste remediation followed by an overview of the engineering involved in the process itself. This is followed by a description of waste form production at a chemical level followed by a section describing different process streams that have undergone the FBSR process. The third section describes the resulting mineral product in terms of phases that are present and the abilitymore » of the waste form to encapsulate hazardous and radioactive wastes from several sources. Following this description is a presentation of the physical properties of the granular and monolith waste form product including and contaminant release mechanisms. The last section gives a brief summary of this chapter and includes a section on the strengths associated with this waste form and the needs for additional data and remaining questions yet to be answered. The reader is directed elsewhere for more information on other waste forms such as Cast Stone (Lockrem, 2005), Ceramicrete (Singh et al., 1997, Wagh et al., 1999) and geopolymers (Kyritsis et al., 2009; Russell et al., 2006).« less

Plasma catalytic reforming of methane

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

Bromberg, L.; Cohn, D.R.; Rabinovich, A.

1998-08-01

Thermal plasma technology can be efficiently used in the production of hydrogen and hydrogen-rich gases from methane and a variety of fuels. This paper describes progress in plasma reforming experiments and calculations of high temperature conversion of methane using heterogeneous processes. The thermal plasma is a highly energetic state of matter that is characterized by extremely high temperatures (several thousand degrees Celsius) and high degree of dissociation and substantial degree of ionization. The high temperatures accelerate the reactions involved in the reforming process. Hydrogen-rich gas (50% H{sub 2}, 17% CO and 33% N{sub 2}, for partial oxidation/water shifting) can bemore » efficiently made in compact plasma reformers. Experiments have been carried out in a small device (2--3 kW) and without the use of efficient heat regeneration. For partial oxidation/water shifting, it was determined that the specific energy consumption in the plasma reforming processes is 16 MJ/kg H{sub 2} with high conversion efficiencies. Larger plasmatrons, better reactor thermal insulation, efficient heat regeneration and improved plasma catalysis could also play a major role in specific energy consumption reduction and increasing the methane conversion. A system has been demonstrated for hydrogen production with low CO content ({approximately} 1.5%) with power densities of {approximately} 30 kW (H{sub 2} HHV)/liter of reactor, or {approximately} 10 m{sup 3}/hr H{sub 2} per liter of reactor. Power density should further increase with increased power and improved design.« less

Apparatus and methods of reheating gas turbine cooling steam and high pressure steam turbine exhaust in a combined cycle power generating system

DOEpatents

Tomlinson, Leroy Omar; Smith, Raub Warfield

2002-01-01

In a combined cycle system having a multi-pressure heat recovery steam generator, a gas turbine and steam turbine, steam for cooling gas turbine components is supplied from the intermediate pressure section of the heat recovery steam generator supplemented by a portion of the steam exhausting from the HP section of the steam turbine, steam from the gas turbine cooling cycle and the exhaust from the HP section of the steam turbine are combined for flow through a reheat section of the HRSG. The reheated steam is supplied to the IP section inlet of the steam turbine. Thus, where gas turbine cooling steam temperature is lower than optimum, a net improvement in performance is achieved by flowing the cooling steam exhausting from the gas turbine and the exhaust steam from the high pressure section of the steam turbine in series through the reheater of the HRSG for applying steam at optimum temperature to the IP section of the steam turbine.

SURVEY ON PREVACUUM HIGH-PRESSURE STEAM STERILIZERS.

PubMed

DARMADY, E M; DREWETT, S E; HUGHES, K E

1964-03-01

None of the 10 prevacuum high-pressure sterilizers of different makes tested was able to produce and maintain the conditions advocated by the Medical Research Council working party on high-pressure steam sterilizers (1959) or by Knox and Penikett (1958) with the result that steam did not penetrate adequately the single challenge load and it was not sterilized. The sterilization of ;group drums' of various sizes and contents was erratic and tended to give operators a false sense of security. An alarming number of minor engineering faults were present in seven out of 10 machines tested and they require very much more skilled maintenance than is being given at the moment. The possibility of centralizing sterilizers to central sterile supply departments and placing them under the care of a regional engineer cannot be too highly recommended. The presence of undetected ;leaks' and a failure to draw a prevacuum of 20 mm. even with a steam burst interferes with sterilization of a challenge load. A leak test should be performed twice daily and should not exceed more than 1 mm. in one minute at 20 mm. absolute. The centre of the load should be monitored by crossed tapes or Brownes tubes in each sterilizing cycle. Although the challenge load was sterilized when the chamber was filled to capacity, a more reliable cycle consisting of a double prevacuum of 20 mm. or more with intermediate steam burst to 10 lb. ensured the sterilizing of a single challenge load, which could be adequately controlled by the chamber drain temperature.

Survey on prevacuum high-pressure steam sterilizers

PubMed Central

Darmady, E. M.; Drewett, S. E.; Hughes, K. E. A.

1964-01-01

None of the 10 prevacuum high-pressure sterilizers of different makes tested was able to produce and maintain the conditions advocated by the Medical Research Council working party on high-pressure steam sterilizers (1959) or by Knox and Penikett (1958) with the result that steam did not penetrate adequately the single challenge load and it was not sterilized. The sterilization of `group drums' of various sizes and contents was erratic and tended to give operators a false sense of security. An alarming number of minor engineering faults were present in seven out of 10 machines tested and they require very much more skilled maintenance than is being given at the moment. The possibility of centralizing sterilizers to central sterile supply departments and placing them under the care of a regional engineer cannot be too highly recommended. The presence of undetected `leaks' and a failure to draw a prevacuum of 20 mm. even with a steam burst interferes with sterilization of a challenge load. A leak test should be performed twice daily and should not exceed more than 1 mm. in one minute at 20 mm. absolute. The centre of the load should be monitored by crossed tapes or Brownes tubes in each sterilizing cycle. Although the challenge load was sterilized when the chamber was filled to capacity, a more reliable cycle consisting of a double prevacuum of 20 mm. or more with intermediate steam burst to 10 lb. ensured the sterilizing of a single challenge load, which could be adequately controlled by the chamber drain temperature. PMID:14149935

Chemical Looping Autothermal Reforming at a 120 kW Pilot Rig

NASA Astrophysics Data System (ADS)

Bofhàr-Nordenkampf, Johannes; Pröll, Tobias; Kolbitsch, Philipp; Hofbauer, Hermann

Chemical looping with selective oxygen transport allows two step combustion or autothermal reforming without mixing of fuel and air. The reactor system consists of two reactors, an air reactor and a fuel reactor with a suitable oxygen carrier that transports the necessary oxygen for operation. In the present study, a highly active nickel based oxygen carrier is tested in a novel dual circulating fluidized bed (DCFB) system at a scale of 120 kW fuel power. The mean particle size of the oxygen carrier is 120 μm and the pilot rig is fueled with natural gas. For the investigated oxygen carrier high CH4 conversion is achieved. Air/fuel ratio is varied at three different fuel reactor temperatures. For chemical looping reforming one can observe synthesis gas composition close to thermodynamic equilibrium. In spite of the fact that no additional steam has been added to the fuel besides the one present through steam fluidization of the loop seals, coke formation does not occur at global stoichiometric air/fuel ratios above 0.46.

Reformer Fuel Injector

NASA Technical Reports Server (NTRS)

Suder, Jennifer L.

2004-01-01

Today's form of jet engine power comes from what is called a gas turbine engine. This engine is on average 14% efficient and emits great quantities of green house gas carbon dioxide and air pollutants, Le. nitrogen oxides and sulfur oxides. The alternate method being researched involves a reformer and a solid oxide fuel cell (SOFC). Reformers are becoming a popular area of research within the industry scale. NASA Glenn Research Center's approach is based on modifying the large aspects of industry reforming processes into a smaller jet fuel reformer. This process must not only be scaled down in size, but also decrease in weight and increase in efficiency. In comparison to today's method, the Jet A fuel reformer will be more efficient as well as reduce the amount of air pollutants discharged. The intent is to develop a 10kW process that can be used to satisfy the needs of commercial jet engines. Presently, commercial jets use Jet-A fuel, which is a kerosene based hydrocarbon fuel. Hydrocarbon fuels cannot be directly fed into a SOFC for the reason that the high temperature causes it to decompose into solid carbon and Hz. A reforming process converts fuel into hydrogen and supplies it to a fuel cell for power, as well as eliminating sulfur compounds. The SOFC produces electricity by converting H2 and CO2. The reformer contains a catalyst which is used to speed up the reaction rate and overall conversion. An outside company will perform a catalyst screening with our baseline Jet-A fuel to determine the most durable catalyst for this application. Our project team is focusing on the overall research of the reforming process. Eventually we will do a component evaluation on the different reformer designs and catalysts. The current status of the project is the completion of buildup in the test rig and check outs on all equipment and electronic signals to our data system. The objective is to test various reformer designs and catalysts in our test rig to determine the most

Bench-Scale Monolith Autothermal Reformer Catalyst Screening Evaluations in a Micro-Reactor With Jet-A Fuel

NASA Technical Reports Server (NTRS)

Tomsik, Thomas M.; Yen, Judy C.H.; Budge, John R.

2006-01-01

Solid oxide fuel cell systems used in the aerospace or commercial aviation environment require a compact, light-weight and highly durable catalytic fuel processor. The fuel processing method considered here is an autothermal reforming (ATR) step. The ATR converts Jet-A fuel by a reaction with steam and air forming hydrogen (H2) and carbon monoxide (CO) to be used for production of electrical power in the fuel cell. This paper addresses the first phase of an experimental catalyst screening study, looking at the relative effectiveness of several monolith catalyst types when operating with untreated Jet-A fuel. Six monolith catalyst materials were selected for preliminary evaluation and experimental bench-scale screening in a small 0.05 kWe micro-reactor test apparatus. These tests were conducted to assess relative catalyst performance under atmospheric pressure ATR conditions and processing Jet-A fuel at a steam-to-carbon ratio of 3.5, a value higher than anticipated to be run in an optimized system. The average reformer efficiencies for the six catalysts tested ranged from 75 to 83 percent at a constant gas-hourly space velocity of 12,000 hr 1. The corresponding hydrocarbon conversion efficiency varied from 86 to 95 percent during experiments run at reaction temperatures between 750 to 830 C. Based on the results of the short-duration 100 hr tests reported herein, two of the highest performing catalysts were selected for further evaluation in a follow-on 1000 hr life durability study in Phase II.

Robust and Low-Cost Flame-Treated Wood for High-Performance Solar Steam Generation.

PubMed

Xue, Guobin; Liu, Kang; Chen, Qian; Yang, Peihua; Li, Jia; Ding, Tianpeng; Duan, Jiangjiang; Qi, Bei; Zhou, Jun

2017-05-03

Solar-enabled steam generation has attracted increasing interest in recent years because of its potential applications in power generation, desalination, and wastewater treatment, among others. Recent studies have reported many strategies for promoting the efficiency of steam generation by employing absorbers based on carbon materials or plasmonic metal nanoparticles with well-defined pores. In this work, we report that natural wood can be utilized as an ideal solar absorber after a simple flame treatment. With ultrahigh solar absorbance (∼99%), low thermal conductivity (0.33 W m -1 K -1 ), and good hydrophilicity, the flame-treated wood can localize the solar heating at the evaporation surface and enable a solar-thermal efficiency of ∼72% under a solar intensity of 1 kW m -2 , and it thus represents a renewable, scalable, low-cost, and robust material for solar steam applications.

Downhole steam injector

DOEpatents

Donaldson, A. Burl; Hoke, Donald E.

1983-01-01

An improved downhole steam injector has an angled water orifice to swirl the water through the device for improved heat transfer before it is converted to steam. The injector also has a sloped diameter reduction in the steam chamber to throw water that collects along the side of the chamber during slant drilling into the flame for conversion to steam. In addition, the output of the flame chamber is beveled to reduce hot spots and increase efficiency, and the fuel-oxidant inputs are arranged to minimize coking.

Downhole steam quality measurement

DOEpatents

Lee, D.O.; Montoya, P.C.; Muir, J.F.; Wayland, J.R. Jr.

1985-06-19

The present invention relates to an empirical electrical method for remote sensing of steam quality utilizing flow-through grids which allow measurement of the electrical properties of a flowing two-phase mixture. The measurement of steam quality in the oil field is important to the efficient application of steam assisted recovery of oil. Because of the increased energy content in higher quality steam it is important to maintain the highest possible steam quality at the injection sandface. The effectiveness of a steaming operation without a measure of steam quality downhole close to the point of injection would be difficult to determine. Therefore, a need exists for the remote sensing of steam quality.

Practical achievements on biomass steam gasification in a rotary tubular coiled-downdraft reactor.

PubMed

Andrew, Renny; Gokak, D T; Sharma, Pankaj; Gupta, Shalini

2016-12-01

Today, the impending stringent environmental norms and concerns about the depletion of fossil fuel reserves have added impetus on development of cutting edge technologies for production of alternative fuels from renewable sources, like biomass. The concept of biomass pyro-gasification offers a platform for production of (a) hydrogen, (b) hydrocarbons and (c) value added chemicals, etc. In this context, there exists potential for hydrogen production from biomass by superheated steam gasification. Apart from H 2 , gaseous products of biomass steam gasification contain CO, CH 4 and other hydrocarbons that can be converted to hydrogen through cracking, steam reforming and water gas shift reactions. In the present work, the characteristics of biomass steam gasification in an indigenously designed rotary tubular coiled-downdraft reactor for high value gaseous fuel production from rice husk was studied through a series of experiments. The robust reactor system enhances biomass conversion to gaseous products by improved mass and heat transfer within the system induced by a coiled flow pattern with increased heat transfer area. Also, the system has improved upon the reliability of operation and offered greater continuity of the process and easier control in comparison with a conventional process by making use of an innovative gas cooler assembly and efficient venturi-mixing system for biomass and steam. Subsequently, the effects of reactor temperature, steam-to-biomass ratio and residence time on overall product gas yield and hydrogen yield were investigated. From the experimental results, it can be deduced that an optimum reactor temperature of 750 °C, steam-to-biomass ratio of 2.0 and a residence time of 3.0 min contributed highest gas yield (1.252 Nm 3  kg -1 moisture-free biomass). Based on the obtained experimental results, a projected potential hydrogen yield of 8.6 wt% of the moisture-free biomass could be achieved, and is also practical for production of

Accelerated Weathering of Fluidized Bed Steam Reformation Material Under Hydraulically Unsaturated Conditions

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

Pierce, Eric M.

2007-09-16

To predict the long-term fate of low- and high-level waste forms in the subsurface over geologic time scales, it is important to understand the behavior of the corroding waste forms under conditions the mimic to the open flow and transport properties of a subsurface repository. Fluidized bed steam reformation (FBSR), a supplemental treatment technology option, is being considered as a waste form for the immobilization of low-activity tank waste. To obtain the fundamental information needed to evaluate the behavior of the FBSR waste form under repository relevant conditions and to monitor the long-term behavior of this material, an accelerated weatheringmore » experiment is being conducted with the pressurized unsaturated flow (PUF) apparatus. Unlike other accelerated weathering test methods (product consistency test, vapor hydration test, and drip test), PUF experiments are conducted under hydraulically unsaturated conditions. These experiments are unique because they mimic the vadose zone environment and allow the corroding waste form to achieve its final reaction state. Results from this on-going experiment suggest the volumetric water content varied as a function of time and reached steady state after 160 days of testing. Unlike the volumetric water content, periodic excursions in the solution pH and electrical conductivity have been occurring consistently during the test. Release of elements from the column illustrates a general trend of decreasing concentration with increasing reaction time. Normalized concentrations of K, Na, P, Re (a chemical analogue for 99Tc), and S are as much as 1 × 104 times greater than Al, Cr, Si, and Ti. After more than 600 days of testing, the solution chemistry data collected to-date illustrate the importance of understanding the long-term behavior of the FBSR product under conditions that mimic the open flow and transport properties of a subsurface repository.« less

A novel approach to the experimental study on methane/steam reforming kinetics using the Orthogonal Least Squares method

NASA Astrophysics Data System (ADS)

Sciazko, Anna; Komatsu, Yosuke; Brus, Grzegorz; Kimijima, Shinji; Szmyd, Janusz S.

2014-09-01

For a mathematical model based on the result of physical measurements, it becomes possible to determine their influence on the final solution and its accuracy. However, in classical approaches, the influence of different model simplifications on the reliability of the obtained results are usually not comprehensively discussed. This paper presents a novel approach to the study of methane/steam reforming kinetics based on an advanced methodology called the Orthogonal Least Squares method. The kinetics of the reforming process published earlier are divergent among themselves. To obtain the most probable values of kinetic parameters and enable direct and objective model verification, an appropriate calculation procedure needs to be proposed. The applied Generalized Least Squares (GLS) method includes all the experimental results into the mathematical model which becomes internally contradicted, as the number of equations is greater than number of unknown variables. The GLS method is adopted to select the most probable values of results and simultaneously determine the uncertainty coupled with all the variables in the system. In this paper, the evaluation of the reaction rate after the pre-determination of the reaction rate, which was made by preliminary calculation based on the obtained experimental results over a Nickel/Yttria-stabilized Zirconia catalyst, was performed.

Enhancement of Glycerol Steam Reforming Activity and Thermal Stability by Incorporating CeO2 and TiO2 in Ni- and Co-MCM-41 Catalysts

NASA Astrophysics Data System (ADS)

Dade, William N.

Hydrogen (H2) has many applications in industry with current focus shifted to production of hydrocarbon fuels and valuable oxygenates using the Fischer-Tropsch technology and direct use in proton exchange membrane fuel cell (PEMFC). Hydrogen is generally produced via steam reforming of natural gas or alcohols like methanol and ethanol. Glycerol, a by-product of biodiesel production process, is currently considered to be one of the most attractive sources of sustainable H2 due to its high H/C ratio and bio-based origin. Ni and Co based catalysts have been reported to be active in glycerol steam reforming (GSR); however, deactivation of the catalysts by carbon deposition and sintering under GSR operating conditions is a major challenge. In this study, a series of catalysts containing Ni and Co nanoparticles incorporated in CeO2 and TiO2 modified high surface area MCM-41 have been synthesized using one-pot method. The catalysts are tested for GSR (at H2O/Glycerol mole ratio of 12 and GHSV of 2200 h-1) to study the effect of support modification and reaction temperature (450 - 700 °C) on the product selectivity and long term stability. GSR results revealed that all the catalysts performed significantly well exhibiting over 85% glycerol conversion at 650 °C except Ni catalysts that showed better low temperature activities. Deactivation studies of the catalysts conducted at 650 °C indicated that the Ni-TiO2-MCM-41 and Ni-CeO 2-MCM-41 were resistant to deactivation with ˜100% glycerol conversion for 40 h. In contrast, Co-TiO2-MCM-41 perform poorly as the catalyst rapidly deactivated after 12 h to yield ˜20% glycerol conversion after 40 h. The WAXRD and TGA-DSC analyses of spent catalysts showed a significant amount of coke deposition that might explain catalysts deactivation. The flattening shape of the original BET type IV isotherm with drastic reduction of catalyst surface area can also be responsible for observed drop in catalysts activities.

Steam engine research for solar parabolic dish

NASA Technical Reports Server (NTRS)

Demler, R. L.

1981-01-01

The parabolic dish solar concentrator provides an opportunity to generate high grade energy in a modular system. Most of the capital is projected to be in the dish and its installation. Assurance of a high production demand of a standard dish could lead to dramatic cost reductions. High production volume in turn depends upon maximum application flexibility by providing energy output options, e.g., heat, electricity, chemicals and combinations thereof. Subsets of these options include energy storage and combustion assist. A steam engine design and experimental program is described which investigate the efficiency potential of a small 25 kW compound reheat cycle piston engine. An engine efficiency of 35 percent is estimated for a 700 C steam temperature from the solar receiver.

Chemical characteristics and enzymatic saccharification of lignocellulosic biomass treated using high-temperature saturated steam: comparison of softwood and hardwood.

PubMed

Asada, Chikako; Sasaki, Chizuru; Hirano, Takeshi; Nakamura, Yoshitoshi

2015-04-01

This study investigated the effect of high-temperature saturated steam treatments on the chemical characteristics and enzymatic saccharification of softwood and hardwood. The weight loss and chemical modification of cedar and beech wood pieces treated at 25, 35, and 45 atm for 5 min were determined. Fourier transform infrared and X-ray diffraction analyses indicated that solubilization and removal of hemicellulose and lignin occurred by the steam treatment. The milling treatment of steam-treated wood enhanced its enzymatic saccharification. Maximum enzymatic saccharification (i.e., 94% saccharification rate of cellulose) was obtained using steam-treated beech at 35 atm for 5 min followed by milling treatment for 1 min. However, the necessity of the milling treatment for efficient enzymatic saccharification is dependent on the wood species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Performance of the Fluidized Bed Steam Reforming Product Under Hydraulically Unsaturated Conditions

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

Neeway, James J.; Qafoku, Nikolla; Williams, Benjamin D.

2014-05-01

Currently, several candidates for secondary waste immobilization at the Hanford site in the State of Washington, USA are being considered. To demonstrate the durability of the product in the unsaturated Integrated Disposal Facility (IDF) at the site, a series of tests have been performed one of the candidate materials using the Pressurized Unsaturated Flow (PUF) system. The material that was tested was the Fluidized Bed Steam Reformer (FBSR) granular product and the granular product encapsulated in a geopolymer matrix. The FBSR product is composed primarily of an insoluble sodium aluminosilicate matrix with the dominant phases being feldspathoid minerals mostly nepheline,more » sodalite, and nosean. The PUF test method allows for the accelerated weathering of materials, including radioactive waste forms, under hydraulically unsaturated conditions, thus mimicking the open-flow and transport properties that most likely will be present at the IDF. The experiments show a trend of decreasing tracer release as a function of time for several of the elements released from the material including Na, Si, Al, and Cs. However, some of the elements, notably I and Re, show a steady release throughout the yearlong test. This result suggests that the release of these minerals from the sodalite cage occurs at a different rate compared with the dissolution of the predominant nepheline phase.« less

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.

Hydrogen generation having CO₂ removal with steam reforming

DOEpatents

Kandaswamy, Duraiswamy; Chellappa, Anand S.; Knobbe, Mack

2015-07-28

A method for producing hydrogen using fuel cell off gases, the method feeding hydrocarbon fuel to a sulfur adsorbent to produce a desulfurized fuel and a spent sulfur adsorbent; feeding said desulfurized fuel and water to an adsorption enhanced reformer that comprises of a plurality of reforming chambers or compartments; reforming said desulfurized fuel in the presence of a one or more of a reforming catalyst and one or more of a CO₂ adsorbent to produce hydrogen and a spent CO₂ adsorbent; feeding said hydrogen to the anode side of the fuel cell; regenerating said spent CO₂ adsorbents using the fuel cell cathode off-gases, producing a flow of hydrogen by cycling between said plurality of reforming chambers or compartments in a predetermined timing sequence; and, replacing the spent sulfur adsorbent with a fresh sulfur adsorbent at a predetermined time.

Steam gasification of acid-hydrolysis biomass CAHR for clean syngas production.

PubMed

Chen, Guanyi; Yao, Jingang; Yang, Huijun; Yan, Beibei; Chen, Hong

2015-03-01

Main characteristics of gaseous product from steam gasification of acid-hydrolysis biomass CAHR have been investigated experimentally. The comparison in terms of evolution of syngas flow rate, syngas quality and apparent thermal efficiency was made between steam gasification and pyrolysis in the lab-scale apparatus. The aim of this study was to determine the effects of temperature and steam to CAHR ratio on gas quality, syngas yield and energy conversion. The results showed that syngas and energy yield were better with gasification compared to pyrolysis under identical thermal conditions. Both high gasification temperature and introduction of proper steam led to higher gas quality, higher syngas yield and higher energy conversion efficiency. However, excessive steam reduced hydrogen yield and energy conversion efficiency. The optimal value of S/B was found to be 3.3. The maximum value of energy ratio was 0.855 at 800°C with the optimal S/B value. Copyright © 2014 Elsevier Ltd. All rights reserved.

Hydrogen production from steam reforming of ethylene glycol over iron loaded on MgO

NASA Astrophysics Data System (ADS)

Chen, Mingqiang; Wang, Yishuang; Liang, Tian; Yang, Jie; Yang, Zhonglian

2017-01-01

In this study, a series of Fe-based catalysts loaded on MgO were prepared by a precipitation technique. And they were tested in hydrogen production from steam reforming of ethylene glycol (SRE), which was a representative model compound of fast bio-oil. The catalysts were characterized by XRD, SEM and H2-TPR analysis. The results showed that the crystalline phases of catalysts contained Fe2O3 (Hematite), Fe3O4 (Magnetite), Fe2MgO4 (iron magnesium oxide) and MgO, and morphology of MgO was changed from the rugby-ball like particles to spherical particles with the addition of Fe. In addition, the catalytic test results indicated that the 18%Fe/MgO catalyst exhibited the highest ethylene glycol conversion (˜99.8%) and H2 molar percent (˜77%) during at the following conditions: H2O/C molar ratio is 5˜7, the feeding rate is 14 mL/h and the reaction temperature at 600˜650°C. Furthermore, the 18%Fe/MgO catalyst can keep outstanding stability during SRE for 12 h.

Ammonia synthesis. Ammonia synthesis by N₂ and steam electrolysis in molten hydroxide suspensions of nanoscale Fe₂O₃.

PubMed

Licht, Stuart; Cui, Baochen; Wang, Baohui; Li, Fang-Fang; Lau, Jason; Liu, Shuzhi

2014-08-08

The Haber-Bosch process to produce ammonia for fertilizer currently relies on carbon-intensive steam reforming of methane as a hydrogen source. We present an electrochemical pathway in which ammonia is produced by electrolysis of air and steam in a molten hydroxide suspension of nano-Fe2O3. At 200°C in an electrolyte with a molar ratio of 0.5 NaOH/0.5 KOH, ammonia is produced at 1.2 volts (V) under 2 milliamperes per centimeter squared (mA cm(-2)) of applied current at coulombic efficiency of 35% (35% of the applied current results in the six-electron conversion of N2 and water to ammonia, and excess H2 is cogenerated with the ammonia). At 250°C and 25 bar of steam pressure, the electrolysis voltage necessary for 2 mA cm(-2) current density decreased to 1.0 V. Copyright © 2014, American Association for the Advancement of Science.

Solar central receiver reformer system for ammonia plants

NASA Astrophysics Data System (ADS)

1980-07-01

Details of the conceptual design, economic analysis, and development plan for a solar central receiver system for retrofitting the Valley Nitrogen Producers, Inc., El Centro, California 600 ST/SD Ammonia Plant are presented. The retrofit system consists of a solar central receiver reformer (SCRR) operating in parallel with the existing fossil fired reformer. Steam and hydrocarbon react in the catalyst filled tubes of the inner cavity receiver to form a hydrogen rich mixture which is the syngas feed for the ammonia production. The SCRR system displaces natural gas presently used in the fossil reformer combustion chamber. The solar reformer retrofit system characteristics and its interface with the existing plant are simple, incorporating state of the art components with proven technology. A northfield composed of one thousand forty second generation heliostats provides solar energy to the receiver which is positioned on top of a 90 meter high steel tower. The overall economics of this system can provide over 20% discount cash flow rate of return with proper investment and market conditions.

The health sector reforms and the efficiency of public hospitals in Turkey: provincial markets.

PubMed

Sulku, Seher Nur

2012-10-01

Turkey initiated the 'Health Transformation Programme' (HTP) in 2003 to align its health care system with the European Union and OECD countries. This study investigates the impact of these reforms on the efficiency of public hospitals. Our study would contribute to the existing literature with a comprehensive analysis of the health system in a developing country. We employ the data envelopment approach and the Malmquist index to comparatively examine before and after the reform years. Our analyses compare the performances of public hospitals served in provincial markets. Inputs of number of beds, number of primary care physician, and number of specialists, and how they are used to produce outputs of inpatient discharges, outpatient visits and surgical operations are investigated. Indeed, as the performance indicators dead rate, hospital bed occupation rate and average length of stay are considered. The HTP was generally successful in boosting productivity due to advancements in technology and technical efficiency but in the socio-economically disadvantaged provinces productivity gains have not been achieved. The average technical efficiency gains took place because of the significantly improved scale efficiencies, as the average pure technical efficiency slightly improved. Lastly, the hospital performance indicators have not improved in the short run. It appears that the expected benefits from the health reforms in Turkey have been partially achieved in the short run.

Solar central receiver reformer system for ammonia plants

NASA Astrophysics Data System (ADS)

1980-07-01

An overview of a study to retrofit the Valley Nitrogen Producers, Inc., El Centro, California 600 ST/SD Ammonia Plant with Solar Central Receiver Technology is presented. The retrofit system consists of a solar central receiver reformer (SCRR) operating in parallel with the existing fossil fired reformer. Steam and hydrocarbon react in the catalyst filled tubes of the inner cavity receiver to form a hydrogen rich mixture which is the syngas feed for the ammonia production. The SCRR system will displace natural gas presently used in the fossil reformer combustion chamber.

More steam for Kern River

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

Rintoul, B.

1973-02-01

While production generally is declining elsewhere in California, the Kern River field continues to post gains. The field last year produced at an all-time high for the second year in a row, putting out at least 1.5 million bbl more than in its previous peak year. There is every reason to believe that gains will continue through this year. Steam is in the factor that underlies Kern River's resurgence, and Getty Oil Co., the field's premier steamer, recently added to its already imposing array of steam-generating equipment a pair of large boilers, each capable of generating 240 million btus permore » hr. Along with expansion of the steaming effort the company also expanded its water-treating facilities, making sure there will be plenty of feed water to fuel the steam generators at work in the field. The new boilers are being used to furnish steam to 136 wells in a steam displacement project. The purpose of going to a larger generator has been to gain higher efficiency. The components that have made Getty Oil the leading steamer at Kern River and the field, in turn, the world capital for oil-field steam operations include shallow wells, steam generators and--since 1969--a computer. The entire project is described in detail.« less

Between Efficiency, Capability and Recognition: Competing Epistemes in Global Governance Reforms

ERIC Educational Resources Information Center

Chan, Jennifer

2007-01-01

This article examines global governance reforms as a site of contestation between three different "truths"/epistemes (the market, human rights principles, and cultural identity) in terms of the competing principles of efficiency, capability, and recognition. Nancy Fraser's conceptions of participation parity and a dialogical approach of…

The development of a control system for a small high speed steam microturbine generator system

NASA Astrophysics Data System (ADS)

Alford, A.; Nichol, P.; Saunders, M.; Frisby, B.

2015-08-01

Steam is a widely used energy source. In many situations steam is generated at high pressures and then reduced in pressure through control valves before reaching point of use. An opportunity was identified to convert some of the energy at the point of pressure reduction into electricity. To take advantage of a market identified for small scale systems, a microturbine generator was designed based on a small high speed turbo machine. This machine was packaged with the necessary control valves and systems to allow connection of the machine to the grid. Traditional machines vary the speed of the generator to match the grid frequency. This was not possible due to the high speed of this machine. The characteristics of the rotating unit had to be understood to allow a control that allowed export of energy at the right frequency to the grid under the widest possible range of steam conditions. A further goal of the control system was to maximise the efficiency of generation under all conditions. A further complication was to provide adequate protection for the rotating unit in the event of the loss of connection to the grid. The system to meet these challenges is outlined with the solutions employed and tested for this application.

Experimental research of heterogeneous nuclei in superheated steam

NASA Astrophysics Data System (ADS)

Bartoš, Ondřej; Kolovratník, Michal; Šmíd, Bohuslav; Hrubý, Jan

2016-03-01

A mobile steam expansion chamber has been developed to investigate experimentally homogeneous and heterogeneous nucleation processes in steam, both in the laboratory and at power plants using the steam withdrawn from the steam turbine. The purpose of the device is to provide new insight into the physics of nonequilibrium wet steam formation, which is one of the factors limiting the efficiency and reliability of steam turbines. The expanded steam or a mixture of steam with a non-condensable gas rapidly expands in the expansion chamber. Due to adiabatic cooling, the temperature drops below the dew point of the steam at a given pressure. When reaching a sufficiently high supersaturation, droplets are nucleated. By tuning the supersaturation in the so-called nucleation pulse, particles of various size ranges can be activated. This fact is used in the present study to measure the aerosol particles present in the air. Homogeneous nucleation was negligible in this case. The experiment demonstrates the functionality of the device, data acquisition system and data evaluation methods.

Method for improving catalyst function in auto-thermal and partial oxidation reformer-based processors

DOEpatents

Ahmed, Shabbir; Papadias, Dionissios D.; Lee, Sheldon H.D.; Ahluwalia, Rajesh K.

2014-08-26

The invention provides a method for reforming fuel, the method comprising contacting the fuel to an oxidation catalyst so as to partially oxidize the fuel and generate heat; warming incoming fuel with the heat while simultaneously warming a reforming catalyst with the heat; and reacting the partially oxidized fuel with steam using the reforming catalyst.

Slab reformer

DOEpatents

Spurrier, Francis R.; DeZubay, Egon A.; Murray, Alexander P.; Vidt, Edward J.

1984-02-07

Slab-shaped high efficiency catalytic reformer configurations particularly useful for generation of fuels to be used in fuel cell based generation systems. A plurality of structures forming a generally rectangular peripheral envelope are spaced about one another to form annular regions, an interior annular region containing a catalytic bed and being regeneratively heated on one side by a hot comubstion gas and on the other side by the gaseous products of the reformation. An integrally mounted combustor is cooled by impingement of incoming oxidant.

Slab reformer

DOEpatents

Spurrier, Francis R.; DeZubay, Egon A.; Murray, Alexander P.; Vidt, Edward J.

1985-03-12

Slab-shaped high efficiency catalytic reformer configurations particularly useful for generation of fuels to be used in fuel cell based generation systems. A plurality of structures forming a generally rectangular peripheral envelope are spaced about one another to form annular regions, an interior annular region containing a catalytic bed and being regeneratively heated on one side by a hot combustion gas and on the other side by the gaseous products of the reformation. An integrally mounted combustor is cooled by impingement of incoming oxidant.

Slab reformer

NASA Technical Reports Server (NTRS)

Spurrier, Francis R. (Inventor); DeZubay, Egon A. (Inventor); Murray, Alexander P. (Inventor); Vidt, Edward J. (Inventor)

1984-01-01

Slab-shaped high efficiency catalytic reformer configurations particularly useful for generation of fuels to be used in fuel cell based generation systems. A plurality of structures forming a generally rectangular peripheral envelope are spaced about one another to form annular regions, an interior annular region containing a catalytic bed and being regeneratively heated on one side by a hot comubstion gas and on the other side by the gaseous products of the reformation. An integrally mounted combustor is cooled by impingement of incoming oxidant.

Slab reformer

NASA Technical Reports Server (NTRS)

Spurrier, Francis R. (Inventor); DeZubay, Egon A. (Inventor); Murray, Alexander P. (Inventor); Vidt, Edward J. (Inventor)

1985-01-01

Slab-shaped high efficiency catalytic reformer configurations particularly useful for generation of fuels to be used in fuel cell based generation systems. A plurality of structures forming a generally rectangular peripheral envelope are spaced about one another to form annular regions, an interior annular region containing a catalytic bed and being regeneratively heated on one side by a hot combustion gas and on the other side by the gaseous products of the reformation. An integrally mounted combustor is cooled by impingement of incoming oxidant.

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.

Project DEEP STEAM

NASA Astrophysics Data System (ADS)

Aeschliman, D. P.; Clay, R. G.; Donaldson, A. B.; Eisenhawer, S. W.; Fox, R. L.; Johnson, D. R.; Mulac, A. J.

1982-01-01

The objective of Project DEEP STEAM is to develop the technology to economically produce heavy oils from deep reservoirs. The tasks included in this project are the development of thermally efficient delivery systems and downhole steam generation systems. During the period January 1-March 31, 1981, effort has continued on a low pressure combustion downhole generator (Rocketdyne), and on two high pressure designs (Foster-Miller Associates, Sandia National Laboratories). The Sandia design was prepared for deployment in the Wilmington Field at Long Beach, California. Progress continued on the Min-Stress II packer concept at L'Garde, Inc., and on the extruded metal packer at Foster-Miller. Initial bare string field data are reported on the insulated tubular test at Lloydminster, Saskatchewan, Canada.

RADIOACTIVE DEMONSTRATION OF FINAL MINERALIZED WASTE FORMS FOR HANFORD WASTE TREATMENT PLANT SECONDARY WASTE BY FLUIDIZED BED STEAM REFORMING USING THE BENCH SCALE REFORMER PLATFORM

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

Crawford, C.; Burket, P.; Cozzi, A.

2012-02-02

The U.S. Department of Energy's Office of River Protection (ORP) is responsible for the retrieval, treatment, immobilization, and disposal of Hanford's tank waste. Currently there are approximately 56 million gallons of highly radioactive mixed wastes awaiting treatment. A key aspect of the River Protection Project (RPP) cleanup mission is to construct and operate the Waste Treatment and Immobilization Plant (WTP). The WTP will separate the tank waste into high-level and low-activity waste (LAW) fractions, both of which will subsequently be vitrified. The projected throughput capacity of the WTP LAW Vitrification Facility is insufficient to complete the RPP mission in themore » time frame required by the Hanford Federal Facility Agreement and Consent Order, also known as the Tri-Party Agreement (TPA), i.e. December 31, 2047. Therefore, Supplemental Treatment is required both to meet the TPA treatment requirements as well as to more cost effectively complete the tank waste treatment mission. In addition, the WTP LAW vitrification facility off-gas condensate known as WTP Secondary Waste (WTP-SW) will be generated and enriched in volatile components such as {sup 137}Cs, {sup 129}I, {sup 99}Tc, Cl, F, and SO{sub 4} that volatilize at the vitrification temperature of 1150 C in the absence of a continuous cold cap (that could minimize volatilization). The current waste disposal path for the WTP-SW is to process it through the Effluent Treatment Facility (ETF). Fluidized Bed Steam Reforming (FBSR) is being considered for immobilization of the ETF concentrate that would be generated by processing the WTP-SW. The focus of this current report is the WTP-SW. FBSR offers a moderate temperature (700-750 C) continuous method by which WTP-SW wastes can be processed irrespective of whether they contain organics, nitrates, sulfates/sulfides, chlorides, fluorides, volatile radionuclides or other aqueous components. The FBSR technology can process these wastes into a crystalline

Slab reformer

DOEpatents

Spurrier, F.R.; DeZubay, E.A.; Murray, A.P.; Vidt, E.J.

1984-02-07

Slab-shaped high efficiency catalytic reformer configurations are disclosed particularly useful for generation of fuels to be used in fuel cell based generation systems. A plurality of structures forming a generally rectangular peripheral envelope are spaced about one another to form annular regions, an interior annular region containing a catalytic bed and being regeneratively heated on one side by a hot combustion gas and on the other side by the gaseous products of the reformation. An integrally mounted combustor is cooled by impingement of incoming oxidant. 14 figs.

Autothermal and partial oxidation reformer-based fuel processor, method for improving catalyst function in autothermal and partial oxidation reformer-based processors

DOEpatents

Ahmed, Shabbir; Papadias, Dionissios D.; Lee, Sheldon H. D.; Ahluwalia, Rajesh K.

2013-01-08

The invention provides a fuel processor comprising a linear flow structure having an upstream portion and a downstream portion; a first catalyst supported at the upstream portion; and a second catalyst supported at the downstream portion, wherein the first catalyst is in fluid communication with the second catalyst. Also provided is a method for reforming fuel, the method comprising contacting the fuel to an oxidation catalyst so as to partially oxidize the fuel and generate heat; warming incoming fuel with the heat while simultaneously warming a reforming catalyst with the heat; and reacting the partially oxidized fuel with steam using the reforming catalyst.

Characterization and Leaching Tests of the Fluidized Bed Steam Reforming (FBSR) Waste Form for LAW Immobilization

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

Neeway, James J.; Qafoku, Nikolla; Brown, Christopher F.

2013-10-01

Several supplemental technologies for treating and immobilizing Hanford low activity waste (LAW) have been evaluated. One such immobilization technology is the Fluidized Bed Steam Reforming (FBSR) granular product. The FBSR granular product is composed of insoluble sodium aluminosilicate (NAS) feldspathoid minerals. Production of the FBSR mineral product has been demonstrated both at the industrial and laboratory scale. Pacific Northwest National Laboratory (PNNL) was involved in an extensive characterization campaign. This goal of this campaign was study the durability of the FBSR mineral product and the mineral product encapsulated in a monolith to meet compressive strength requirements. This paper gives anmore » overview of results obtained using the ASTM C 1285 Product Consistency Test (PCT), the EPA Test Method 1311 Toxicity Characteristic Leaching Procedure (TCLP), and the ASTMC 1662 Single-Pass Flow-Through (SPFT) test. Along with these durability tests an overview of the characteristics of the waste form has been collected using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), microwave digestions for chemical composition, and surface area from Brunauer, Emmett, and Teller (BET) theory.« less

Thermal chemical recuperation method and system for use with gas turbine systems

DOEpatents

Yang, W.C.; Newby, R.A.; Bannister, R.L.

1999-04-27

A system and method are disclosed for efficiently generating power using a gas turbine, a steam generating system and a reformer. The gas turbine receives a reformed fuel stream and an air stream and produces shaft power and exhaust. Some of the thermal energy from the turbine exhaust is received by the reformer. The turbine exhaust is then directed to the steam generator system that recovers thermal energy from it and also produces a steam flow from a water stream. The steam flow and a fuel stream are directed to the reformer that reforms the fuel stream and produces the reformed fuel stream used in the gas turbine. 2 figs.

Thermal chemical recuperation method and system for use with gas turbine systems

DOEpatents

Yang, Wen-Ching; Newby, Richard A.; Bannister, Ronald L.

1999-01-01

A system and method for efficiently generating power using a gas turbine, a steam generating system (20, 22, 78) and a reformer. The gas turbine receives a reformed fuel stream (74) and an air stream and produces shaft power and exhaust. Some of the thermal energy from the turbine exhaust is received by the reformer (18). The turbine exhaust is then directed to the steam generator system that recovers thermal energy from it and also produces a steam flow from a water stream. The steam flow and a fuel stream are directed to the reformer that reforms the fuel stream and produces the reformed fuel stream used in the gas turbine.

Liquid hydrogen production via hydrogen sulfide methane reformation

NASA Astrophysics Data System (ADS)

Huang, Cunping; T-Raissi, Ali

Hydrogen sulfide (H 2S) methane (CH 4) reformation (H 2SMR) (2H 2S + CH 4 = CS 2 + 4H 2) is a potentially viable process for the removal of H 2S from sour natural gas resources or other methane containing gases. Unlike steam methane reformation that generates carbon dioxide as a by-product, H 2SMR produces carbon disulfide (CS 2), a liquid under ambient temperature and pressure-a commodity chemical that is also a feedstock for the synthesis of sulfuric acid. Pinch point analyses for H 2SMR were conducted to determine the reaction conditions necessary for no carbon lay down to occur. Calculations showed that to prevent solid carbon formation, low inlet CH 4 to H 2S ratios are needed. In this paper, we analyze H 2SMR with either a cryogenic process or a membrane separation operation for production of either liquid or gaseous hydrogen. Of the three H 2SMR hydrogen production flowsheets analyzed, direct liquid hydrogen generation has higher first and second law efficiencies of exceeding 80% and 50%, respectively.

Method and apparatus for improving the performance of a steam driven power system by steam mixing

DOEpatents

Tsiklauri, Georgi V.; Durst, Bruce M.; Prichard, Andrew W.; Reid, Bruce D.; Burritt, James

1998-01-01

A method and apparatus for improving the efficiency and performance of a steam driven power plant wherein addition of steam handling equipment to an existing plant results in a surprising increase in plant performance. For Example, a gas turbine electrical generation system with heat recovery boiler may be installed along with a micro-jet high pressure and a low pressure mixer superheater. Depending upon plant characteristics, the existing moisture separator reheater (MSR) can be either augmented or done away with. The instant invention enables a reduction in T.sub.hot without a derating of the reactor unit, and improves efficiency of the plant's electrical conversion cycle. Coupled with this advantage is a possible extension of the plant's fuel cycle length due to an increased electrical conversion efficiency. The reduction in T.sub.hot further allows for a surprising extension of steam generator life. An additional advantage is the reduction in erosion/corrosion of secondary system components including turbine blades and diaphragms. The gas turbine generator used in the instant invention can also replace or augment existing peak or emergency power needs. Another benefit of the instant invention is the extension of plant life and the reduction of downtime due to refueling.

Influence of the Operational Wear of the Stator Parts of Shroud Seals on the Economic Efficiency of the Steam Turbines

NASA Astrophysics Data System (ADS)

Kostyuk, A. G.; Dmitriev, S. S.; Petrunin, B. N.; Gusev, A. A.

2018-01-01

increase approximately 1.7 times slower than under the similar wear of the ridges of conventional straight-through seals with smooth stator parts. However, this gain in efficiency achieved by replacing the standard smooth-wall seals with the honeycomb seals must be necessarily correlated with the measurement data on the nonconservative shroud forces in conventional axial-radial seals with smooth stator surfaces with a radial clearance of 4 mm, which is almost seven times lower than that in the honeycomb seals with a radial clearance of 0.5 mm. From the results obtained in the work, it follows that the installation of honeycomb shroud seals instead of traditional ridge seals in the high-pressure cylinders (HPCs) of the steam turbines for subcritical steam parameters with high-vibration-resistance rotors that have a sufficient margin of resistance to self-oscillations is undoubtedly advisable from the point of view of increasing the economic efficiency of the turbines. However, the use of honeycomb shroud seals with reduced radial clearances in the HPC parts of the steam turbines for supercritical steam parameters requires special cautiousness, since it is in the area of small clearances that the maximum nonconservative shroud forces capable of causing auto-oscillations of the shafting are observed and these forces are maximal precisely at high pressures.

Factors concerned in the efficient steam sterilization of surgical dressings

PubMed Central

Fallon, R. J.

1961-01-01

Some of the factors affecting the efficient steam sterilization of dressings have been examined. A jacketed sterilizer will process a load more quickly than a sterilizer without a jacket. The level of fore-vacuum is critical and must reach an absolute pressure of 20 mm. Hg (29·2 in.Hg vacuum) or less. This will overcome all conditions of overpacking studied. The level of after-vacuum should be 100 mm. Hg absolute or less, preferably near 50 mm. Hg absolute. Overpacking cannot be defined in terms of weight of a fabric per unit volume of container but occurs when a load is compressed in its container. PMID:13891475

Solar Reforming of Carbon Dioxide to Produce Diesel Fuel

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

Dennis Schuetzle; Robert Schuetzle

2010-12-31

This project focused on the demonstration of an innovative technology, referred to as the Sunexus CO2 Solar Reformer, which utilizes waste CO2 as a feedstock for the efficient and economical production of synthetic diesel fuel using solar thermal energy as the primary energy input. The Sunexus technology employs a two stage process for the conversion of CO2 to diesel fuel. A solar reforming system, including a specially designed reactor and proprietary CO2 reforming catalyst, was developed and used to convert captured CO2 rich gas streams into syngas (primarily hydrogen and carbon monoxide) using concentrated solar energy at high conversion efficiencies.more » The second stage of the system (which has been demonstrated under other funding) involves the direct conversion of the syngas into synthetic diesel fuel using a proprietary catalyst (Terra) previously developed and validated by Pacific Renewable Fuels and Chemicals (PRFC). The overall system energy efficiency for conversion of CO2 to diesel fuel is 74%, due to the use of solar energy. The results herein describe modeling, design, construction, and testing of the Sunexus CO2 Solar Reformer. Extensive parametric testing of the solar reformer and candidate catalysts was conducted and chemical kinetic models were developed. Laboratory testing of the Solar Reformer was successfully completed using various gas mixtures, temperatures, and gas flow rates/space velocities to establish performance metrics which can be employed for the design of commercial plants. A variety of laboratory tests were conducted including dry reforming (CO2 and CH{sub 4}), combination dry/steam reforming (CO2, CH{sub 4} & H{sub 2}O), and tri-reforming (CO2, CH{sub 4}, H{sub 2}O & O{sub 2}). CH{sub 4} and CO2 conversions averaged 95-100% and 50-90% per reformer cycle, respectively, depending upon the temperatures and gas space velocities. No formation of carbon deposits (coking) on the catalyst was observed in any of these tests. A 16 ft

Development of High-Powered Steam Turbines by OAO NPO Central Research and Design Institute for Boilers and Turbines

NASA Astrophysics Data System (ADS)

Mikhailov, V. E.; Khomenok, L. A.; Kovalev, I. A.

2018-01-01

The article provides an overview of the developments by OAO NPO TsKTI aimed at improvement of components and assemblies of new-generation turbine plants for ultra-supercritical steam parameters to be installed at the power-generating facilities in service. The list of the assemblies under development includes cylinder shells, the cylinder's flow paths and rotors, seals, bearings, and rotor cooling systems. The authors consider variants of the shafting-cylinder configurations for which advanced high-pressure and intermediate-pressure cylinders with reactive blading and low-pressure cylinders of conventional design and with counter-current steam flows are proposed and high-pressure rotors, which can increase the economic efficiency and reduce the overall turbine plant dimensions. Materials intended for the equipment components that operate at high temperatures and a steam cooling technique that allows the use of cheaper steel grades owing to the reduction in the metal's working temperature are proposed. A new promising material for the bearing surfaces is described that enables the operation at higher unit pressures. The material was tested on a full-scale test bench at OAO NPO TsKTI and a turbine in operation. Ways of controlling the erosion of the blades in the moisture-steam turbine compartments by the steam heating of the hollow guide blades are considered. To ensure the dynamic stability of the shafting, shroud and diaphragm seals that prevent the development of the destabilizing circulatory forces of the steam flow were devised and trialed. Advanced instrumentation and software are proposed to monitor the condition of the blading and thermal stresses under transient conditions, to diagnose the vibration processes, and to archive the obtained data. Attention is paid to the normalization of the electromagnetic state of the plant in order to prevent the electrolytic erosion of the plant components. The instrumentation intended for monitoring the relevant electric

A SURVEY OF CONVENTIONAL STEAM BOILER EXPERIENCE APPLICABLE TO THE HTGR STEAM GENERATORS

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

Paget, J.A.

1959-10-01

BS>The steam generator of a high temperature gas-cooled reactor consists of tubular heating surface inside a shell which forms part of the primary He circuit of the reactor. When a tube fails in such a steam generator, moisture in the form of steam is released into the He steam and is carried through the reactor where it will cause corrosion and mass transfer of C in the core. A paramount consideration in the design of a steam generator for a high temperature gas-cooled reactor is the prevention of tube failures. Preference, therefore, should be given to a forced circulation design.more » The Loeffler Boiler would be the best from this standpoint alone since only steam enters the tubes, and its circulation rate can be maintained at an adequate value to insure cool tubes regardless of load fluctuations. The next type in the order of preference would be the forced recirculation boiler, since at least the boiier tubes always have an adequate cooling flow regardless of output. The third type in order of preference would be a Sulzer Type boiler since it has a separator to remove dissolved material from the water which is comparible in efficiency to a standard boiler drum and although the flow through evaporator and superheater fluctuates with load, the Sulzer Boiler can be operated as a forced recirculation boiler at low loads. The least desirable type would be a Benson or supercritical boiler which is completely dependent on input water purity for its survival. It is not claimed that Benson or supercritical boilers should not or will not be used in the future for gas-cooled reactors, but only that their use would be the least conservative choice from a tube failure standpoint at the present time. (auth)« less

Educational Management Organizations as High Reliability Organizations: A Study of Victory's Philadelphia High School Reform Work

ERIC Educational Resources Information Center

Thomas, David E.

2013-01-01

This executive position paper proposes recommendations for designing reform models between public and private sectors dedicated to improving school reform work in low performing urban high schools. It reviews scholarly research about for-profit educational management organizations, high reliability organizations, American high school reform, and…

Application of high temperature phase change materials for improved efficiency in waste-to-energy plants.

PubMed

Dal Magro, Fabio; Xu, Haoxin; Nardin, Gioacchino; Romagnoli, Alessandro

2018-03-01

This study reports the thermal analysis of a novel thermal energy storage based on high temperature phase change material (PCM) used to improve efficiency in waste-to-energy plants. Current waste-to-energy plants efficiency is limited by the steam generation cycle which is carried out with boilers composed by water-walls (i.e. radiant evaporators), evaporators, economizers and superheaters. Although being well established, this technology is subjected to limitations related with high temperature corrosion and fluctuation in steam production due to the non-homogenous composition of solid waste; this leads to increased maintenance costs and limited plants availability and electrical efficiency. The proposed solution in this paper consists of replacing the typical refractory brick installed in the combustion chamber with a PCM-based refractory brick capable of storing a variable heat flux and to release it on demand as a steady heat flux. By means of this technology it is possible to mitigate steam production fluctuation, to increase temperature of superheated steam over current corrosion limits (450°C) without using coated superheaters and to increase the electrical efficiency beyond 34%. In the current paper a detailed thermo-mechanical analysis has been carried out in order to compare the performance of the PCM-based refractory brick against the traditional alumina refractory bricks. The PCM considered in this paper is aluminium (and its alloys) whereas its container consists of high density ceramics (such as Al 2 O 3 , AlN and Si 3 N 4 ); the different coefficient of linear thermal expansion for the different materials requires a detailed thermo-mechanical analysis to be carried out to ascertain the feasibility of the proposed technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analysis of experimental characteristics of multistage steam-jet electors of steam turbines

NASA Astrophysics Data System (ADS)

Aronson, K. E.; Ryabchikov, A. Yu.; Brodov, Yu. M.; Brezgin, D. V.; Zhelonkin, N. V.; Murmanskii, I. B.

2017-02-01

A series of questions for specification of physical gas dynamics model in flow range of steam-jet unit and ejector computation methodology, as well as functioning peculiarities of intercoolers, was formulated based on analysis of experimental characteristics of multistage team-jet steam turbines. It was established that coefficient defining position of critical cross-section of injected flow depends on characteristics of the "sound tube" zone. Speed of injected flow within this tube may exceed that of sound, and pressure jumps in work-steam decrease at the same time. Characteristics of the "sound tube" define optimal axial sizes of the ejector. According to measurement results, the part of steam condensing in the first-stage coolant constitutes 70-80% of steam amount supplied into coolant and is almost independent of air content in steam. Coolant efficiency depends on steam pressure defined by operation of steam-jet unit of ejector of the next stage after coolant of steam-jet stage, temperature, and condensing water flow. As a rule, steam entering content of steam-air mixture supplied to coolant is overheated with respect to saturation temperature of steam in the mixture. This should be taken into account during coolant computation. Long-term operation causes changes in roughness of walls of the ejector's mixing chamber. The influence of change of wall roughness on ejector characteristic is similar to the influence of reverse pressure of the steam-jet stage. Until some roughness value, injection coefficient of the ejector stage operating in superlimiting regime hardly changed. After reaching critical roughness, the ejector switches to prelimiting operating regime.

Multi-fuel reformers for fuel cells used in transportation. Phase 1: Multi-fuel reformers

NASA Astrophysics Data System (ADS)

1994-05-01

DOE has established the goal, through the Fuel Cells in Transportation Program, of fostering the rapid development and commercialization of fuel cells as economic competitors for the internal combustion engine. Central to this goal is a safe feasible means of supplying hydrogen of the required purity to the vehicular fuel cell system. Two basic strategies are being considered: (1) on-board fuel processing whereby alternative fuels such as methanol, ethanol or natural gas stored on the vehicle undergo reformation and subsequent processing to produce hydrogen, and (2) on-board storage of pure hydrogen provided by stationary fuel processing plants. This report analyzes fuel processor technologies, types of fuel and fuel cell options for on-board reformation. As the Phase 1 of a multi-phased program to develop a prototype multi-fuel reformer system for a fuel cell powered vehicle, the objective of this program was to evaluate the feasibility of a multi-fuel reformer concept and to select a reforming technology for further development in the Phase 2 program, with the ultimate goal of integration with a DOE-designated fuel cell and vehicle configuration. The basic reformer processes examined in this study included catalytic steam reforming (SR), non-catalytic partial oxidation (POX) and catalytic partial oxidation (also known as Autothermal Reforming, or ATR). Fuels under consideration in this study included methanol, ethanol, and natural gas. A systematic evaluation of reforming technologies, fuels, and transportation fuel cell applications was conducted for the purpose of selecting a suitable multi-fuel processor for further development and demonstration in a transportation application.

Characterization and Leaching Tests of the Fluidized Bed Steam Reforming (FBSR) Waste Form for LAW Immobilization - 13400

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

Neeway, James J.; Qafoku, Nikolla P.; Peterson, Reid A.

2013-07-01

Several supplemental technologies for treating and immobilizing Hanford low activity waste (LAW) have been evaluated. One such immobilization technology is the Fluidized Bed Steam Reforming (FBSR) granular product. The FBSR granular product is composed of insoluble sodium aluminosilicate (NAS) feldspathoid minerals. Production of the FBSR mineral product has been demonstrated both at the industrial and laboratory scale. Pacific Northwest National Laboratory (PNNL) was involved in an extensive characterization campaign. The goal of this campaign was to study the durability of the FBSR mineral product and the encapsulated FBSR product in a geo-polymer monolith. This paper gives an overview of resultsmore » obtained using the ASTM C 1285 Product Consistency Test (PCT), the EPA Test Method 1311 Toxicity Characteristic Leaching Procedure (TCLP), and the ASTMC 1662 Single-Pass Flow-Through (SPFT) test. Along with these durability tests an overview of the characteristics of the waste form has been collected using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), microwave digestions for chemical composition, and surface area from Brunauer, Emmett, and Teller (BET) theory. (authors)« less

Enhanced the enzymatic hydrolysis efficiency of wheat straw after combined steam explosion and laccase pretreatment.

PubMed

Qiu, Weihua; Chen, Hongzhang

2012-08-01

Laccase, capable of selectively degrading lignin while keeping cellulose intact, has been widely applied for the modification and bio-bleaching of pulp. In this study Sclerotium sp. laccase (MSLac) was employed in combination with steam explosion to evaluate the effect of this treatment on cellulose hydrolysis. Combined steam explosion with laccase pretreatment enhanced the cellulose conversion rate of wheat straw no matter in the case of successive (MSLac-Cel) and simultaneous (MSLac+Cel) MSLac and cellulase hydrolysis. The highest cellulose conversion rate of 84.23% was obtained when steam-exploded wheat straw (SEWS) (1.3 MPa, 5 min) was treated by MSLac+Cel at a laccase loading of 0.55 U g(-1) substrate. FT-IR and SEM analyses indicated that MSLac oxidized the phenol and changed electron configuration of the ring, which contributed to loosening the compact wrap of lignin-carbohydrate complex and consequently enhancing the enzymatic hydrolysis efficiency of cellulose. This article provided a promising method for lignocellulose bio-pretreatment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Synthesis gas and olefins from the catalytic autothermal reforming of volatile and non-volatile liquids

NASA Astrophysics Data System (ADS)

Dreyer, Bradon Justin

2007-12-01

The research presented in this thesis develops an understanding of a clean energy process technology, catalytic partial oxidation (CPO). CPO is a process in which a carbon containing fuel, such as a hydrocarbon, is passed over a noble metal catalyst (e.g. rhodium and platinum) to efficiently generate synthesis gas (H2 and CO) and olefins (e.g. ethylene and propylene) in millisecond contact times. Chapter 1 introduces CPO and compares this technology with conventional methods for synthesis gas and olefin production. CPO has several advantages over the traditional synthesis gas and olefin production methods. One advantage includes autothermal operation, requiring no external heat input from furnaces or heat exchangers. Autothermal operation allows these reactors to be built compactly. The short contact-times associated with CPO further enable for high throughput in relatively small reactor systems, and more compact reactors typically translate to faster response times if transient operation is required. Nobel metal based CPO catalysts are also resistant to deactivation, resulting in less catalyst replacement, regeneration, and maintenance, and an increase in operating efficiency. An overview of the many applications of the chemicals produced from CPO is also presented in Chapter 1. The chemicals produced are crucial in generating valuable chemical intermediates that are eventually incorporated in consumer products, medical devices, building structures, and fertilizers. Additionally, H2 can be used as a source of energy in mobile fuel applications. Fuel cells convert H2 and O2 into electricity and water at higher efficiencies than thermal engine generators. Due to the difficulties in H2 storage, these more efficient energy generators are dependent on hydrogen obtained from synthesis gas production in compact, portable fuel reformers, such as CPO reactors. Furthermore, H2 and CO can be used in reducing environmentally harmful emissions. Particularly, the implementation

Perspectives on High School Reform. NCREL Viewpoints, Volume 13

ERIC Educational Resources Information Center

Learning Point Associates / North Central Regional Educational Laboratory (NCREL), 2005

2005-01-01

Viewpoints is a multimedia package containing two audio CDs and a brief, informative booklet. This volume of Viewpoints focuses on issues related to high school reform. This booklet offers background information explaining the issues surrounding high school reform with perspectives from research, policy, and practice. It also provides a list of…

LIQUID BIO-FUEL PRODUCTION FROM NON-FOOD BIOMASS VIA HIGH TEMPERATURE STEAM ELECTROLYSIS

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

G. L. Hawkes; J. E. O'Brien; M. G. McKellar

2011-11-01

Bio-Syntrolysis is a hybrid energy process that enables production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), bio-syntrolysis has the potential to provide a significant alternative petroleum source that could reduce US dependence on imported oil. Combining hydrogen from HTSE with CO from an oxygen-blown biomass gasifier yields syngas to be used as a feedstock for synthesis of liquid transportation fuels via a Fischer-Tropsch process. Conversion of syngas to liquid hydrocarbon fuels, using a biomass-based carbon source, expandsmore » the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A process model of syngas production using high temperature electrolysis and biomass gasification is presented. Process heat from the biomass gasifier is used to heat steam for the hydrogen production via the high temperature steam electrolysis process. Oxygen produced form the electrolysis process is used to control the oxidation rate in the oxygen-blown biomass gasifier. Based on the gasifier temperature, 94% to 95% of the carbon in the biomass becomes carbon monoxide in the syngas (carbon monoxide and hydrogen). Assuming the thermal efficiency of

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.

Thermodynamic analysis of steam-injected advanced gas turbine cycles

NASA Astrophysics Data System (ADS)

Pandey, Devendra; Bade, Mukund H.

2017-12-01

This paper deals with thermodynamic analysis of steam-injected gas turbine (STIGT) cycle. To analyse the thermodynamic performance of steam-injected gas turbine (STIGT) cycles, a methodology based on pinch analysis is proposed. This graphical methodology is a systematic approach proposed for a selection of gas turbine with steam injection. The developed graphs are useful for selection of steam-injected gas turbine (STIGT) for optimal operation of it and helps designer to take appropriate decision. The selection of steam-injected gas turbine (STIGT) cycle can be done either at minimum steam ratio (ratio of mass flow rate of steam to air) with maximum efficiency or at maximum steam ratio with maximum net work conditions based on the objective of plants designer. Operating the steam injection based advanced gas turbine plant at minimum steam ratio improves efficiency, resulting in reduction of pollution caused by the emission of flue gases. On the other hand, operating plant at maximum steam ratio can result in maximum work output and hence higher available power.

Lower pressure heating steam is practical for the distributed dry dilute sulfuric acid pretreatment.

PubMed

Shao, Shuai; Zhang, Jian; Hou, Weiliang; Qureshi, Abdul Sattar; Bao, Jie

2017-08-01

Most studies paid more attention to the pretreatment temperature and the resulted pretreatment efficiency, while ignored the heating media and their scalability to an industry scale. This study aimed to use a relative low pressure heating steam easily provided by steam boiler to meet the requirement of distributed dry dilute acid pretreatment. The results showed that the physical properties of the pretreated corn stover were maintained stable using the steam pressure varying from 1.5, 1.7, 1.9 to 2.1MPa. Enzymatic hydrolysis and high solids loading simultaneous saccharification and fermentation (SSF) results were also satisfying. CFD simulation indicated that the high injection velocity of the low pressure steam resulted in a high steam holdup and made the mixing time of steam and solid corn stover during pretreatment much shorter in comparison with the higher pressure steam. This study provides a design basis for the boiler requirement in distributed pretreatment concept. Copyright © 2017 Elsevier Ltd. All rights reserved.

High performance internal reforming unit for high temperature fuel cells

DOEpatents

Ma, Zhiwen [Sandy Hook, CT; Venkataraman, Ramakrishnan [New Milford, CT; Novacco, Lawrence J [Brookfield, CT

2008-10-07

A fuel reformer having an enclosure with first and second opposing surfaces, a sidewall connecting the first and second opposing surfaces and an inlet port and an outlet port in the sidewall. A plate assembly supporting a catalyst and baffles are also disposed in the enclosure. A main baffle extends into the enclosure from a point of the sidewall between the inlet and outlet ports. The main baffle cooperates with the enclosure and the plate assembly to establish a path for the flow of fuel gas through the reformer from the inlet port to the outlet port. At least a first directing baffle extends in the enclosure from one of the sidewall and the main baffle and cooperates with the plate assembly and the enclosure to alter the gas flow path. Desired graded catalyst loading pattern has been defined for optimized thermal management for the internal reforming high temperature fuel cells so as to achieve high cell performance.

Tri-reforming and combined reforming of methane for producing syngas with desired hydrogen/carbon monoxide ratios

NASA Astrophysics Data System (ADS)

Pan, Wei

This dissertation is an exploratory study of a new process concept for direct production of synthesis gas (CO + H2) with desired H 2/CO ratios (1.5--2.0) for methanol synthesis and F-T synthesis, using CO2 together with steam and unconverted O2 in flue gas from fossil fuel-fired electric power plants to react with methane or natural gas. This new process is called tri-reforming, referring to simultaneous CO2-steam-O2 reforming of methane or natural gas. This study included (1) The investigation of carbon formation in the tri-reforming process. For comparison, carbon formation in the combined reforming and CO2 reforming reaction was studied as well. (2) The effect of reaction conditions and feed compositions on equilibrium composition (e.g. H2/CO ratio) and equilibrium conversions in the tri-reforming process. (3) The role of catalysts in the tri-reforming process, especially the effect of catalysts on CO2 conversion in the presence of H 2O and O2. It was clearly evidenced from this study that CO in the product stream is probably the major source of carbon over Ni/Al2O3 in the equimolar CO2-CH4 reforming at 650°C and 1 atm. Addition of either O2 or H2O into the CO 2 reforming reaction system can suppress carbon formation. It was demonstrated that carbon-free operation can be achieved in the tri-reforming process. A thermodynamic comparison of tri-reforming with feed compositions of (H2O+CO2+0.5O2)/CH4 (mol ratio) = 1 showed that O2 improves equilibrium CH4 conversion, yet greatly decreases equilibrium CO2 conversion. H2O in tri-reforming has a significant effect on the H2/CO ratio in the products, while O2 has a minor effect. A kinetic study and catalytic performance tests indicated that the support in a supported catalyst has a significant role in enhancing CO2 conversion to CO in the presence of H2O and O2 in tri-reforming. The Ni/MgO catalyst showed superior performance with close to equilibrium CH4 and CO2 conversions at 850°C, 1 atm, and 32,000 ml

Natural gas-assisted steam electrolyzer

DOEpatents

Pham, Ai-Quoc; Wallman, P. Henrik; Glass, Robert S.

2000-01-01

An efficient method of producing hydrogen by high temperature steam electrolysis that will lower the electricity consumption to an estimated 65 percent lower than has been achievable with previous steam electrolyzer systems. This is accomplished with a natural gas-assisted steam electrolyzer, which significantly reduces the electricity consumption. Since this natural gas-assisted steam electrolyzer replaces one unit of electrical energy by one unit of energy content in natural gas at one-quarter the cost, the hydrogen production cost will be significantly reduced. Also, it is possible to vary the ratio between the electricity and the natural gas supplied to the system in response to fluctuations in relative prices for these two energy sources. In one approach an appropriate catalyst on the anode side of the electrolyzer will promote the partial oxidation of natural gas to CO and hydrogen, called Syn-Gas, and the CO can also be shifted to CO.sub.2 to give additional hydrogen. In another approach the natural gas is used in the anode side of the electrolyzer to burn out the oxygen resulting from electrolysis, thus reducing or eliminating the potential difference across the electrolyzer membrane.

Design, fabrication and performance evaluation of an integrated reformed methanol fuel cell for portable use

NASA Astrophysics Data System (ADS)

Zhang, Shubin; Zhang, Yufeng; Chen, Junyu; Yin, Congwen; Liu, Xiaowei

2018-06-01

In this paper, an integrated reformed methanol fuel cell (RMFC) as a portable power source is designed, fabricated and tested. The RMFC consists of a methanol steam reformer (MSR), a high temperature proton exchange membrane fuel cell (HT-PEMFC) stack, a microcontroller unit (MCU) and other auxiliaries. First, a system model based on Matlab/Simulink is established to investigate the mass and energy transport characteristics within the whole system. The simulation results suggest a hydrogen flow rate of at least 670 sccm is needed for the system to output 30 W and simultaneously maintain thermal equilibrium. Second, a metallic MSR and an HT-PEMFC stack with 12 cells are fabricated and tested. The tests show that the RMFC system is able to function normally when the performances of all the components meet the minimum requirements. At last, in the experiment of successfully powering a laptop, the RMFC system exhibits a stable performance during the complete work flow of all the phases, namely start-up, output and shutdown. Moreover, with a conservative design of 20 W power rating, maximum energy conversion efficiency of the RMFC system can be achieved (36%), and good stability in long-term operation is shown.

Effects of temperature and pressure on the performance of a solid oxide fuel cell running on steam reformate of kerosene

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

Chick, Lawrence A.; Marina, Olga A.; Coyle, Christopher A.

2013-08-15

A button solid oxide fuel cell with a La0.6Sr0.4Co0.2Fe0.8O3 cathode and a nickel-YSZ anode was tested over a range of temperatures from 650 to 800°C and a range of pressures from 101 to 724 kPa. The fuel was simulated steam-reformed kerosene and the oxidant was air. The observed increases in open circuit voltages (OCV) were accurately predicted by the Nernst equation. Kinetics also increased, although the power boost due to kinetics was about two thirds as large as the boost due to OCV. The total power boost in going from 101 to 724 kPa at 750°C and 0.8 volts wasmore » 66%. Impedance spectroscopy demonstrated a significant decrease in electrodic losses at elevated pressures. Complex impedance spectra were dominated by a combination of low frequency processes that decreased markedly with increasing pressure. A composite of high-frequency processes also decreased with pressure, but to a lesser extent. An empirical algorithm that accurately predicts the increased fuel cell performance at elevated pressures was developed for our results and was also suitable for some, but not all, data reported in the literature.« less

Workshop proceedings: U-bend tube cracking in steam generators

NASA Astrophysics Data System (ADS)

Shoemaker, C. E.

1981-06-01

A design to reduce the rate of tube failure in high pressure feedwater heaters, a number of failed drawn and stress relieved Monel 400 U-bend tubes removed from three high pressure feedwater heaters was examined. Steam extracted from the turbine is used to preheat the boiler feedwater in fossil fuel fired steam plants to improve thermal efficiency. This is accomplished in a series of heaters between the condenser hot well and the boiler. The heaters closest to the boiler handle water at high pressure and temperature. Because of the severe service conditions, high pressure feedwater heaters are frequently tubed with drawn and stress relieved Monel 400.

Simulation of high temperature thermal energy storage system based on coupled metal hydrides for solar driven steam power plants

DOE PAGES

d'Entremont, Anna; Corgnale, Claudio; Hardy, Bruce; ...

2018-01-11

Concentrating solar power plants can achieve low cost and efficient renewable electricity production if equipped with adequate thermal energy storage systems. Metal hydride based thermal energy storage systems are appealing candidates due to their demonstrated potential for very high volumetric energy densities, high exergetic efficiencies, and low costs. The feasibility and performance of a thermal energy storage system based on NaMgH 2F hydride paired with TiCr 1.6Mn 0.2 is examined, discussing its integration with a solar-driven ultra-supercritical steam power plant. The simulated storage system is based on a laboratory-scale experimental apparatus. It is analyzed using a detailed transport model accountingmore » for the thermochemical hydrogen absorption and desorption reactions, including kinetics expressions adequate for the current metal hydride system. The results show that the proposed metal hydride pair can suitably be integrated with a high temperature steam power plant. The thermal energy storage system achieves output energy densities of 226 kWh/m 3, 9 times the DOE SunShot target, with moderate temperature and pressure swings. Also, simulations indicate that there is significant scope for performance improvement via heat-transfer enhancement strategies.« less

Simulation of high temperature thermal energy storage system based on coupled metal hydrides for solar driven steam power plants

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

d'Entremont, Anna; Corgnale, Claudio; Hardy, Bruce

Concentrating solar power plants can achieve low cost and efficient renewable electricity production if equipped with adequate thermal energy storage systems. Metal hydride based thermal energy storage systems are appealing candidates due to their demonstrated potential for very high volumetric energy densities, high exergetic efficiencies, and low costs. The feasibility and performance of a thermal energy storage system based on NaMgH 2F hydride paired with TiCr 1.6Mn 0.2 is examined, discussing its integration with a solar-driven ultra-supercritical steam power plant. The simulated storage system is based on a laboratory-scale experimental apparatus. It is analyzed using a detailed transport model accountingmore » for the thermochemical hydrogen absorption and desorption reactions, including kinetics expressions adequate for the current metal hydride system. The results show that the proposed metal hydride pair can suitably be integrated with a high temperature steam power plant. The thermal energy storage system achieves output energy densities of 226 kWh/m 3, 9 times the DOE SunShot target, with moderate temperature and pressure swings. Also, simulations indicate that there is significant scope for performance improvement via heat-transfer enhancement strategies.« less

In situ XPS study of methanol reforming on PdGa near-surface intermetallic phases

PubMed Central

Rameshan, Christoph; Stadlmayr, Werner; Penner, Simon; Lorenz, Harald; Mayr, Lukas; Hävecker, Michael; Blume, Raoul; Rocha, Tulio; Teschner, Detre; Knop-Gericke, Axel; Schlögl, Robert; Zemlyanov, Dmitry; Memmel, Norbert; Klötzer, Bernhard

2012-01-01

In situ X-ray photoelectron spectroscopy and low-energy ion scattering were used to study the preparation, (thermo)chemical and catalytic properties of 1:1 PdGa intermetallic near-surface phases. Deposition of several multilayers of Ga metal and subsequent annealing to 503–523 K led to the formation of a multi-layered 1:1 PdGa near-surface state without desorption of excess Ga to the gas phase. In general, the composition of the PdGa model system is much more variable than that of its PdZn counterpart, which results in gradual changes of the near-surface composition with increasing annealing or reaction temperature. In contrast to near-surface PdZn, in methanol steam reforming, no temperature region with pronounced CO2 selectivity was observed, which is due to the inability of purely intermetallic PdGa to efficiently activate water. This allows to pinpoint the water-activating role of the intermetallic/support interface and/or of the oxide support in the related supported PdxGa/Ga2O3 systems, which exhibit high CO2 selectivity in a broad temperature range. In contrast, corresponding experiments starting on the purely bimetallic model surface in oxidative methanol reforming yielded high CO2 selectivity already at low temperatures (∼460 K), which is due to efficient O2 activation on PdGa. In situ detected partial and reversible oxidative Ga segregation on intermetallic PdGa is associated with total oxidation of intermediate C1 oxygenates to CO2. PMID:22875996

Oxidation Kinetics of Ferritic Alloys in High-Temperature Steam Environments

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

Parker, Stephen S.; White, Josh; Hosemann, Peter

High-temperature isothermal steam oxidation kinetic parameters of several ferritic alloys were determined by thermogravimetric analysis. We measured the oxidation kinetic constant (k) as a function of temperature from 900°C to 1200°C. The results show a marked increase in oxidation resistance compared to reference Zircaloy-2, with kinetic constants 3–5 orders of magnitude lower across the experimental temperature range. Our results of this investigation supplement previous findings on the properties of ferritic alloys for use as candidate cladding materials and extend kinetic parameter measurements to high-temperature steam environments suitable for assessing accident tolerance for light water reactor applications.

Oxidation Kinetics of Ferritic Alloys in High-Temperature Steam Environments

DOE PAGES

Parker, Stephen S.; White, Josh; Hosemann, Peter; ...

2017-11-03

High-temperature isothermal steam oxidation kinetic parameters of several ferritic alloys were determined by thermogravimetric analysis. We measured the oxidation kinetic constant (k) as a function of temperature from 900°C to 1200°C. The results show a marked increase in oxidation resistance compared to reference Zircaloy-2, with kinetic constants 3–5 orders of magnitude lower across the experimental temperature range. Our results of this investigation supplement previous findings on the properties of ferritic alloys for use as candidate cladding materials and extend kinetic parameter measurements to high-temperature steam environments suitable for assessing accident tolerance for light water reactor applications.

Oxidation Kinetics of Ferritic Alloys in High-Temperature Steam Environments

NASA Astrophysics Data System (ADS)

Parker, Stephen S.; White, Josh; Hosemann, Peter; Nelson, Andrew

2018-02-01

High-temperature isothermal steam oxidation kinetic parameters of several ferritic alloys were determined by thermogravimetric analysis. The oxidation kinetic constant ( k) was measured as a function of temperature from 900°C to 1200°C. The results show a marked increase in oxidation resistance compared to reference Zircaloy-2, with kinetic constants 3-5 orders of magnitude lower across the experimental temperature range. The results of this investigation supplement previous findings on the properties of ferritic alloys for use as candidate cladding materials and extend kinetic parameter measurements to high-temperature steam environments suitable for assessing accident tolerance for light water reactor applications.

The Effect of Condensing Steam Turbine Exhaust Hood Body Geometry on Exhaust Performance Efficiency

NASA Astrophysics Data System (ADS)

Gribin, V. G.; Paramonov, A. N.; Mitrokhova, O. M.

2018-06-01

The article presents data from combined numerical and experimental investigations of the effect that the overall dimensions of the exhaust hood of a steam turbine with an underslung condenser has on the aerodynamic losses in the hood. Owing to the properly selected minimum permissible overall dimensions of the exhaust hood, more efficient operation of this turbine component is achieved, better vibration stability of the turbine set shaft line is obtained, and lower costs are required for arranging the steam turbine plant in the turbine building. Experiments have shown that the main overall dimensions of the hood body have a determining effect on the exhaust hood flow path profile and on its aerodynamic performance. Owing to properly selected ratios between the exhaust hood body main sizes without a diffuser, a total loss coefficient equal to approximately unity has been obtained. By using an axial-radial diffuser, the energy loss can be decreased by 30-40% depending on the geometrical parameters and level of velocities in the inlet section of a hood having the optimal overall dimensions. By using the obtained results, it becomes possible to evaluate the overall dimensions necessary for achieving the maximal aerodynamic hood efficiency and, as a consequence, to obtain better technical and economic indicators of the turbine plant as a whole already at the initial stage of its designing. If a need arises to select overall dimensions smaller than their optimal values, the increase of energy loss can be estimated using the presented dependences. The cycle of investigations was carried out on the experimental setups available in the fundamental research laboratory of the Moscow Power Engineering Institute National University's Department of Steam and Gas Turbines with due regard to the operating parameters and similarity criteria.

9. HIGH POWER SPRAY IN MEN'S STEAM ROOM. Hot ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. HIGH POWER SPRAY IN MEN'S STEAM ROOM. - Hot Springs National Park, Bathhouse Row, Fordyce Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

Hydrogen from catalytic reforming of biomass-derived hydrocarbons in liquid water

NASA Astrophysics Data System (ADS)

Cortright, R. D.; Davda, R. R.; Dumesic, J. A.

2002-08-01

Concerns about the depletion of fossil fuel reserves and the pollution caused by continuously increasing energy demands make hydrogen an attractive alternative energy source. Hydrogen is currently derived from nonrenewable natural gas and petroleum, but could in principle be generated from renewable resources such as biomass or water. However, efficient hydrogen production from water remains difficult and technologies for generating hydrogen from biomass, such as enzymatic decomposition of sugars, steam-reforming of bio-oils and gasification, suffer from low hydrogen production rates and/or complex processing requirements. Here we demonstrate that hydrogen can be produced from sugars and alcohols at temperatures near 500K in a single-reactor aqueous-phase reforming process using a platinum-based catalyst. We are able to convert glucose-which makes up the major energy reserves in plants and animals-to hydrogen and gaseous alkanes, with hydrogen constituting 50% of the products. We find that the selectivity for hydrogen production increases when we use molecules that are more reduced than sugars, with ethylene glycol and methanol being almost completely converted into hydrogen and carbon dioxide. These findings suggest that catalytic aqueous-phase reforming might prove useful for the generation of hydrogen-rich fuel gas from carbohydrates extracted from renewable biomass and biomass waste streams.

Hydrogen from catalytic reforming of biomass-derived hydrocarbons in liquid water.

PubMed

Cortright, R D; Davda, R R; Dumesic, J A

2002-08-29

Concerns about the depletion of fossil fuel reserves and the pollution caused by continuously increasing energy demands make hydrogen an attractive alternative energy source. Hydrogen is currently derived from nonrenewable natural gas and petroleum, but could in principle be generated from renewable resources such as biomass or water. However, efficient hydrogen production from water remains difficult and technologies for generating hydrogen from biomass, such as enzymatic decomposition of sugars, steam-reforming of bio-oils and gasification, suffer from low hydrogen production rates and/or complex processing requirements. Here we demonstrate that hydrogen can be produced from sugars and alcohols at temperatures near 500 K in a single-reactor aqueous-phase reforming process using a platinum-based catalyst. We are able to convert glucose -- which makes up the major energy reserves in plants and animals -- to hydrogen and gaseous alkanes, with hydrogen constituting 50% of the products. We find that the selectivity for hydrogen production increases when we use molecules that are more reduced than sugars, with ethylene glycol and methanol being almost completely converted into hydrogen and carbon dioxide. These findings suggest that catalytic aqueous-phase reforming might prove useful for the generation of hydrogen-rich fuel gas from carbohydrates extracted from renewable biomass and biomass waste streams.

Parametric performance analysis of steam-injected gas turbine with a thermionic-energy-converter-lined combustor

NASA Technical Reports Server (NTRS)

Choo, Y. K.; Burns, R. K.

1982-01-01

The performance of steam-injected gas turbines having combustors lined with thermionic energy converters (STIG/TEC systems) was analyzed and compared with that of two baseline systems; a steam-injected gas turbine (without a TEC-lined combustor) and a conventional combined gas turbine/steam turbine cycle. Common gas turbine parameters were assumed for all of the systems. Two configurations of the STIG/TEC system were investigated. In both cases, steam produced in an exhaust-heat-recovery boiler cools the TEC collectors. It is then injected into the gas combustion stream and expanded through the gas turbine. The STIG/TEC system combines the advantage of gas turbine steam injection with the conversion of high-temperature combustion heat by TEC's. The addition of TEC's to the baseline steam-injected gas turbine improves both its efficiency and specific power. Depending on system configuration and design parameters, the STIG/TEC system can also achieve higher efficiency and specific power than the baseline combined cycle.

Effect of thermal barrier coatings on the performance of steam and water-cooled gas turbine/steam turbine combined cycle system

NASA Technical Reports Server (NTRS)

Nainiger, J. J.

1978-01-01

An analytical study was made of the performance of air, steam, and water-cooled gas-turbine/steam turbine combined-cycle systems with and without thermal-barrier coatings. For steam cooling, thermal barrier coatings permit an increase in the turbine inlet temperature from 1205 C (2200 F), resulting in an efficiency improvement of 1.9 percentage points. The maximum specific power improvement with thermal barriers is 32.4 percent, when the turbine inlet temperature is increased from 1425 C (2600 F) to 1675 C (3050 F) and the airfoil temperature is kept the same. For water cooling, the maximum efficiency improvement is 2.2 percentage points at a turbine inlet temperature of 1683 C (3062 F) and the maximum specific power improvement is 36.6 percent by increasing the turbine inlet temperature from 1425 C (2600 F) to 1730 C (3150 F) and keeping the airfoil temperatures the same. These improvements are greater than that obtained with combined cycles using air cooling at a turbine inlet temperature of 1205 C (2200 F). The large temperature differences across the thermal barriers at these high temperatures, however, indicate that thermal stresses may present obstacles to the use of coatings at high turbine inlet temperatures.

In-Service Monitoring of Steam Pipe Systems at High Temperatures

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Lih, Shyh-Shiuh; Badescu, Mircea; Bao, Xiaoqi; Sherrit, Stewart; Scott, James S.; Blosiu, Julian O.; Widholm, Scott E.

2011-01-01

An effective, in-service health monitoring system is needed to track water condensation in real time through the walls of steam pipes. The system is required to measure the height of the condensed water from outside the pipe, while operating at temperatures that are as high as 250 C. The system needs to account for the effects of water flow and cavitation. In addition, it is desired that the system does not require perforating the pipes and thereby reducing the structural integrity. Generally, steam pipes are used as part of the district heating system carrying steam from central power stations under the streets to heat, cool, or supply power to high-rise buildings and businesses. This system uses ultrasonic waves in pulse-echo and acquires reflected signal data. Via autocorrelation, it determines the water height while eliminating the effect of noise and multiple reflections from the wall of the pipe. The system performs nondestructive monitoring through the walls of steam pipes, and automatically measures the height of condensed water while operating at the high-temperature conditions of 250 C. For this purpose, the ultrasonic pulse-echo method is used where the time-of-flight of the wave reflections inside the water are measured, and it is multiplied by the wave velocity to determine the height. The pulse-echo test consists of emitting ultrasonic wave pulses from a piezoelectric transducer and receiving the reflections from the top and bottom of the condensed water. A single transducer is used as a transmitter as well as the receiver of the ultrasonic waves. To obtain high resolution, a broadband transducer is used and the frequency can be in the range of 2.25 to 10 MHz, providing sharp pulses in the time domain allowing for higher resolution in identifying the individual reflections.

Estimation of transient heat flux density during the heat supply of a catalytic wall steam methane reformer

NASA Astrophysics Data System (ADS)

Settar, Abdelhakim; Abboudi, Saïd; Madani, Brahim; Nebbali, Rachid

2018-02-01

Due to the endothermic nature of the steam methane reforming reaction, the process is often limited by the heat transfer behavior in the reactors. Poor thermal behavior sometimes leads to slow reaction kinetics, which is characterized by the presence of cold spots in the catalytic zones. Within this framework, the present work consists on a numerical investigation, in conjunction with an experimental one, on the one-dimensional heat transfer phenomenon during the heat supply of a catalytic-wall reactor, which is designed for hydrogen production. The studied reactor is inserted in an electric furnace where the heat requirement of the endothermic reaction is supplied by electric heating system. During the heat supply, an unknown heat flux density, received by the reactive flow, is estimated using inverse methods. In the basis of the catalytic-wall reactor model, an experimental setup is engineered in situ to measure the temperature distribution. Then after, the measurements are injected in the numerical heat flux estimation procedure, which is based on the Function Specification Method (FSM). The measured and estimated temperatures are confronted and the heat flux density which crosses the reactor wall is determined.

Evaluation of thermodynamically favourable operating conditions for production of hydrogen in three different reforming technologies

NASA Astrophysics Data System (ADS)

Seo, Y.-S.; Shirley, A.; Kolaczkowski, S. T.

With the aid of thermodynamic analysis using AspenPlus™, the characteristics of three different types of reforming process are investigated. These include: steam-methane reforming (SMR), partial oxidation (POX) and autothermal reforming (ATR). Thereby, favourable operating conditions are identified for each process. The optimum steam-to-carbon (S:C) ratio of the SMR reactor is found to be 1.9. The optimum air ratio of the POX reactor is 0.3 at a preheat temperature of 312 °C. The optimum air ratio and S:C ratio of the ATR reactor are 0.29 and 0.35, respectively at a preheat temperature of 400 °C. Simulated material and energy balances show that the CH 4 flow rates required to generate 1 mol s -1 of hydrogen are 0.364 mol s -1 for POX, 0.367 mol s -1 for ATR and 0.385 mol s -1 for the SMR. These results demonstrate that the POX reforming system has the lowest energy cost to produce the same amount of hydrogen from CH 4.

Concept of turbines for ultrasupercritical, supercritical, and subcritical steam conditions

NASA Astrophysics Data System (ADS)

Mikhailov, V. E.; Khomenok, L. A.; Pichugin, I. I.; Kovalev, I. A.; Bozhko, V. V.; Vladimirskii, O. A.; Zaitsev, I. V.; Kachuriner, Yu. Ya.; Nosovitskii, I. A.; Orlik, V. G.

2017-11-01

The article describes the design features of condensing turbines for ultrasupercritical initial steam conditions (USSC) and large-capacity cogeneration turbines for super- and subcritical steam conditions having increased steam extractions for district heating purposes. For improving the efficiency and reliability indicators of USSC turbines, it is proposed to use forced cooling of the head high-temperature thermally stressed parts of the high- and intermediate-pressure rotors, reaction-type blades of the high-pressure cylinder (HPC) and at least the first stages of the intermediate-pressure cylinder (IPC), the double-wall HPC casing with narrow flanges of its horizontal joints, a rigid HPC rotor, an extended system of regenerative steam extractions without using extractions from the HPC flow path, and the low-pressure cylinder's inner casing moving in accordance with the IPC thermal expansions. For cogeneration turbines, it is proposed to shift the upper district heating extraction (or its significant part) to the feedwater pump turbine, which will make it possible to improve the turbine plant efficiency and arrange both district heating extractions in the IPC. In addition, in the case of using a disengaging coupling or precision conical bolts in the coupling, this solution will make it possible to disconnect the LPC in shifting the turbine to operate in the cogeneration mode. The article points out the need to intensify turbine development efforts with the use of modern methods for improving their efficiency and reliability involving, in particular, the use of relatively short 3D blades, last stages fitted with longer rotor blades, evaporation techniques for removing moisture in the last-stage diaphragm, and LPC rotor blades with radial grooves on their leading edges.

RADIOACTIVE DEMONSTRATIONS OF FLUIDIZED BED STEAM REFORMING AS A SUPPLEMENTARY TREATMENT FOR HANFORD'S LOW ACTIVITY WASTE AND SECONDARY WASTES

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

Jantzen, C.; Crawford, C.; Cozzi, A.

The U.S. Department of Energy's Office of River Protection (ORP) is responsible for the retrieval, treatment, immobilization, and disposal of Hanford's tank waste. Currently there are approximately 56 million gallons of highly radioactive mixed wastes awaiting treatment. A key aspect of the River Protection Project (RPP) cleanup mission is to construct and operate the Waste Treatment and Immobilization Plant (WTP). The WTP will separate the tank waste into high-level and low-activity waste (LAW) fractions, both of which will subsequently be vitrified. The projected throughput capacity of the WTP LAW Vitrification Facility is insufficient to complete the RPP mission in themore » time frame required by the Hanford Federal Facility Agreement and Consent Order, also known as the Tri-Party Agreement (TPA), i.e. December 31, 2047. Therefore, Supplemental Treatment is required both to meet the TPA treatment requirements as well as to more cost effectively complete the tank waste treatment mission. The Supplemental Treatment chosen will immobilize that portion of the retrieved LAW that is not sent to the WTP's LAW Vitrification facility into a solidified waste form. The solidified waste will then be disposed on the Hanford site in the Integrated Disposal Facility (IDF). In addition, the WTP LAW vitrification facility off-gas condensate known as WTP Secondary Waste (WTP-SW) will be generated and enriched in volatile components such as Cs-137, I-129, Tc-99, Cl, F, and SO4 that volatilize at the vitrification temperature of 1150 C in the absence of a continuous cold cap. The current waste disposal path for the WTP-SW is to recycle it to the supplemental LAW treatment to avoid a large steady state accumulation in the pretreatment-vitrification loop. Fluidized Bed Steam Reforming (FBSR) offers a moderate temperature (700-750 C) continuous method by which LAW and/or WTP-SW wastes can be processed irrespective of whether they contain organics, nitrates, sulfates

Hydrogen production from algal biomass via steam gasification.

PubMed

Duman, Gozde; Uddin, Md Azhar; Yanik, Jale

2014-08-01

Algal biomasses were tested as feedstock for steam gasification in a dual-bed microreactor in a two-stage process. Gasification experiments were carried out in absence and presence of catalyst. The catalysts used were 10% Fe₂O₃-90% CeO₂ and red mud (activated and natural forms). Effects of catalysts on tar formation and gasification efficiencies were comparatively investigated. It was observed that the characteristic of algae gasification was dependent on its components and the catalysts used. The main role of the catalyst was reforming of the tar derived from algae pyrolysis, besides enhancing water gas shift reaction. The tar reduction levels were in the range of 80-100% for seaweeds and of 53-70% for microalgae. Fe₂O₃-CeO₂ was found to be the most effective catalyst. The maximum hydrogen yields obtained were 1036 cc/g algae for Fucus serratus, 937 cc/g algae for Laminaria digitata and 413 cc/g algae for Nannochloropsis oculata. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sulfur poisoning of CeO[subscript 2]-Al[subscript 2]O[subscript 3]-supported mono- and bi-metallic Ni and Rh catalysts in steam reforming of liquid hydrocarbons at low and high temperatures

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

Xie, Chao; Chen, Yongsheng; Li, Yan

2010-12-01

In order to develop a better understanding on sulfur poisoning of reforming catalysts in fuel processing for hydrogen production, steam reforming of liquid hydrocarbons was performed over CeO{sub 2}-Al{sub 2}O{sub 3} supported monometallic Ni and Rh and bimetallic Rh-Ni catalysts at 550 and 800 C. XANES was used to identify the sulfur species in the used catalysts and to study their impacts on the metal surface properties probed by XPS. It was found that both monometallic catalysts rapidly deactivated at 550 C, and showed poor sulfur tolerance. Although ineffective for the Ni catalyst, increasing the temperature to 800 C dramaticallymore » improved the sulfur tolerance of the Rh catalyst. XANES revealed that metal sulfide and organic sulfide are the dominant sulfur species on the used Ni catalyst, while sulfonate and sulfate predominate on the used Rh catalyst. The presence of sulfur induced severe carbon deposition on the Ni catalyst at 800 C. The superior sulfur tolerance of the Rh catalyst at 800 C may be associated with its capability in sulfur oxidation. It is likely that the formation of the oxygen-shielded sulfur structure of sulfonate and sulfate can suppress the poisoning impact of sulfur on Rh by inhibiting direct rhodium-sulfur interaction. Moreover, XPS indicated that the metal surface properties of the Rh catalysts after the reaction without and with sulfur at 800 C are similar, suggesting that sulfur poisoning on Rh was mitigated under the high-temperature condition. Although the Rh-Ni catalyst exhibited better sulfur tolerance than the monometallic catalysts at 550 C, its catalytic performance was inferior compared with the Rh catalyst in the sulfur-containing reaction at 800 C probably due to the severe carbon deposition on the bimetallic catalyst.« less

Disinfection of heat-sensitive material by low-temperature steam and formaldehyde

PubMed Central

Alder, V. G.; Brown, Anne M.; Gillespie, W. A.

1966-01-01

Steam under subatmospheric pressure at temperatures below 90°C. rapidly killed nonsporing organisms after air had been removed by a high-vacuum pump. Most bacterial spores were killed but small proportions of the populations were very resistant. The destruction of spores was not logarithmic. The addition of formaldehyde vapour to the steam greatly increased its sterilizing power, with deep penetration into fabrics and destruction of spores. Penetration into wide tubes was good, but was poor in narrow tubes. Most fabrics, plastics, and instruments were unharmed. Low-temperature steam with formaldehyde is probably as efficient a sterilizing agent as ethylene oxide. PMID:5904988

Indirect-cycle FBR cooled by supercritical steam-concept and design

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

Yoshiaki, Oka; Tatjana, Jevremovic; Sei-ichi, Koshizuka

1993-01-01

Neutronic and thermal-hydraulic design of an in direct-cycle supercritical steam-cooled fast breeder reactor (SCFBR-I) is carried out to find a way to make low-cost FBRs (Ref. 1). The advantages of supercritical steam cooling are high thermal efficiency, low pumping power, simplified system (no primary steam generators and no Loeffler boilers), and the use of experienced technology in fossil-fired power plants. The design goals are fissile fuel breeding (compound system doubling time below 30 yr), 1000-M(electric) class out-put, high fuel discharge burnup, and a long refueling period. The coolant void reactivity should be negative throughout fuel lifetime because the loss-of-coolant accidentmore » is the design-basis accident. These goals have never been satisfied simultaneously in previous SCFBRs.« less

ABB's advanced steam turbine program

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

Chellini, R.

Demand for industrial steam turbines for combined-cycle applications and cogeneration plants has influenced turbine manufacturers to standardize their machines to reduce delivery time and cost. ABB, also a supplier of turnkey plants, manufactures steam turbines in Finspong, Sweden, at the former ASEA Stal facilities and in Nuernberg, Germany, at the former AEG facilities. The companies have joined forces, setting up the advanced Steam Turbine Program (ATP) that, once completed, will cover a power range from two to 100 MW. The company decided to use two criteria as a starting point, the high efficiency design of the Swedish turbines and themore » high reliability of the German machines. Thus, the main task was combining the two designs in standard machines that could be assembled quickly into predefined packages to meet specific needs of combined-cycle and cogeneration plants specified by customers. In carrying out this project, emphasis was put on cost reduction as one of the main goals. The first results of the ATP program, presented by ABB Turbinen Nuernberg, is the range of 2-30 MW turbines covered by two frame sizes comprising standard components supporting the thermodynamic module. An important feature is the standardization of the speed reduction gearbox.« less

Radioactive demonstration of final mineralized waste forms for Hanford waste treatment plant secondary waste (WTP-SW) by fluidized bed steam reforming (FBSR) using the bench scale reformer platform

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

Crawford, C.; Burket, P.; Cozzi, A.

2014-08-01

The U.S. Department of Energy’s Office of River Protection (ORP) is responsible for the retrieval, treatment, immobilization, and disposal of Hanford’s tank waste. Currently there are approximately 56 million gallons of highly radioactive mixed wastes awaiting treatment. A key aspect of the River Protection Project (RPP) cleanup mission is to construct and operate the Waste Treatment and Immobilization Plant (WTP). The WTP will separate the tank waste into high-level and low-activity waste (LAW) fractions, both of which will subsequently be vitrified. The projected throughput capacity of the WTP LAW Vitrification Facility is insufficient to complete the RPP mission in themore » time frame required by the Hanford Federal Facility Agreement and Consent Order, also known as the Tri-Party Agreement (TPA), i.e. December 31, 2047. Therefore, Supplemental Treatment is required both to meet the TPA treatment requirements as well as to more cost effectively complete the tank waste treatment mission. In addition, the WTP LAW vitrification facility off-gas condensate known as WTP Secondary Waste (WTP-SW) will be generated and enriched in volatile components such as 137Cs, 129I, 99Tc, Cl, F, and SO4 that volatilize at the vitrification temperature of 1150°C in the absence of a continuous cold cap (that could minimize volatilization). The current waste disposal path for the WTP-SW is to process it through the Effluent Treatment Facility (ETF). Fluidized Bed Steam Reforming (FBSR) is being considered for immobilization of the ETF concentrate that would be generated by processing the WTP-SW. The focus of this current report is the WTP-SW.« less

Gamma irradiation and steam pretreatment of jute stick powder for the enhancement of dye adsorption efficiency

NASA Astrophysics Data System (ADS)

Parvin, Fahmida; Sultana, Nargis; Habib, S. M. Ahsan; Bhoumik, Nikhil Chandra

2017-11-01

The aim of this study is to find out the facile and effective pretreatment technique to enhance the capacity of jute stick powder (JSP) in adsorbing dye from raw textile effluent. Hence, different pretreatment techniques, i.e., radiation treatment, alkali treatment, ammonia treatment, steam treatment and CaCl2 treatment were applied to JSP and the adsorbing performance were examined for synthetic dye solutions (Blue FCL and Red RL dye). Different gamma radiation doses were applied on JSP and optimum dye removal efficiency was found at 500 krad in removing these two dyes (50 ppm) from solutions. Among the different pretreatment techniques, gamma irradiated JSP (500 Krad) exhibits highest dye uptake capacity for RED RL dye, whereas steam-treated JSP shows highest performance in adsorbing blue FCL dye. Subsequently, we applied the gamma irradiated and steam-treated JSP on real textile effluent (RTE) and these two techniques shows potentiality in adsorbing dye from raw textile effluent and in reducing BOD5, COD load and TOC to some extent as well. Fourier transform infrared spectroscopy (FTIR) analysis also proved that dye has been adsorbed on pretreated JSP.

The vacuum system reform and test of the super-critical 600mw unit

NASA Astrophysics Data System (ADS)

Yan, Tao; Wan, Zhonghai; Lu, Jin; Chen, Wen; Cai, Wen

2017-11-01

The deficiencies of the designed vacuum system of the super-critical unit is pointed out in this paper, and then it is reformed by the steam ejector. The experimental results show that the vacuum of the condenser can be improved, the coal consumption can be reduced and the plant electricity consumption can be lowered dramatically at a small cost of the steam energy consumption. Meanwhile, the water-ring vacuum pumps cavitation problems can be solved.

Impact of High-School Reform Initiatives Using the Pygmalion Effect

ERIC Educational Resources Information Center

Buryanek, Kimberly K.

2010-01-01

In 2006, a 9th-period program and an A, B, C, Incomplete grading policy were implemented as high school reform initiatives in a rural high school in the Midwest. The purpose of this qualitative research study was to determine how teachers interpreted the effect of the A, B, C, Incomplete grading policy and the 9th period reform initiatives at the…

Solar steam generation by heat localization.

PubMed

Ghasemi, Hadi; Ni, George; Marconnet, Amy Marie; Loomis, James; Yerci, Selcuk; Miljkovic, Nenad; Chen, Gang

2014-07-21

Currently, steam generation using solar energy is based on heating bulk liquid to high temperatures. This approach requires either costly high optical concentrations leading to heat loss by the hot bulk liquid and heated surfaces or vacuum. New solar receiver concepts such as porous volumetric receivers or nanofluids have been proposed to decrease these losses. Here we report development of an approach and corresponding material structure for solar steam generation while maintaining low optical concentration and keeping the bulk liquid at low temperature with no vacuum. We achieve solar thermal efficiency up to 85% at only 10 kW m(-2). This high performance results from four structure characteristics: absorbing in the solar spectrum, thermally insulating, hydrophilic and interconnected pores. The structure concentrates thermal energy and fluid flow where needed for phase change and minimizes dissipated energy. This new structure provides a novel approach to harvesting solar energy for a broad range of phase-change applications.

Cogeneration steam turbines from Siemens: New solutions

NASA Astrophysics Data System (ADS)

Kasilov, V. F.; Kholodkov, S. V.

2017-03-01

The Enhanced Platform system intended for the design and manufacture of Siemens AG turbines is presented. It combines organizational and production measures allowing the production of various types of steam-turbine units with a power of up to 250 MWel from standard components. The Enhanced Platform designs feature higher efficiency, improved reliability, better flexibility, longer overhaul intervals, and lower production costs. The design features of SST-700 and SST-900 steam turbines are outlined. The SST-700 turbine is used in backpressure steam-turbine units (STU) or as a high-pressure cylinder in a two-cylinder condensing turbine with steam reheat. The design of an SST-700 single-cylinder turbine with a casing without horizontal split featuring better flexibility of the turbine unit is presented. An SST-900 turbine can be used as a combined IP and LP cylinder (IPLPC) in steam-turbine or combined-cycle power units with steam reheat. The arrangements of a turbine unit based on a combination of SST-700 and SST-900 turbines or SST-500 and SST-800 turbines are presented. Examples of this combination include, respectively, PGU-410 combinedcycle units (CCU) with a condensing turbine and PGU-420 CCUs with a cogeneration turbine. The main equipment items of a PGU-410 CCU comprise an SGT5-4000F gas-turbine unit (GTU) and STU consisting of SST-700 and SST-900RH steam turbines. The steam-turbine section of a PGU-420 cogeneration power unit has a single-shaft turbine unit with two SST-800 turbines and one SST-500 turbine giving a power output of N el. STU = 150 MW under condensing conditions.

Efficiency and equity implications of the health care reforms.

PubMed

Carr-Hill, R A

1994-11-01

The purpose of the paper is to reflect on the recent health care reforms in both developed and developing countries, in the light of the evidence that has accumulated over the last few years about the efficiency and equity of different fiscal and organisational arrangements. The scene is set by a brief review of the definitions of efficiency and equity and of the confusions that often arise; and of the problems of making assessments in practice with real data. The evidence about effectiveness, efficiency and equity at the macro level are reviewed: among OECD countries, there is little evidence that variations in the levels and composition of health service expenditure actually affect levels of health; equity in financing and delivery appears to mirror equity in other sectors in the same countries; about the only solid--although rather limp--conclusion which is transferable is that costs can be contained best via global budgeting. The range of reforms in the North is sketched: despite calls to give people 'freedom' to opt out, public finances continues to be preferred among OECD countries; and the evidence that health care markets can actually function is 'weak'. Whilst geographical redistribution of finance has proved to be possible, inequalities in health remain in most countries. But the overwhelming impression is that the quality of the data base for many of these studies is appalling, and the analytice techniques used are simplistic. The move to introduce user charges in the South is discussed. It seems unlikely that they will raise a significant fraction of overall revenue; exemptions intended for the poor do not always work; and other trends are likely to exacerbate the patchy coverage of health care systems in the South. The final section reflects on the pressures for increased accountability. The emphasis on consumerism in the North has led to an increasing number of poorly designed 'patient satisfaction' surveys; in the South, there has been an increasing

Two decades of reforms. Appraisal of the financial reforms in the Russian public healthcare sector.

PubMed

Gordeev, Vladimir S; Pavlova, Milena; Groot, Wim

2011-10-01

This paper reviews the empirical evidence on the outcomes of the financial reforms in the Russian public healthcare sector. A systematic literature review identified 37 relevant publications that presented empirical evidence on changes in quality, equity, efficiency and sustainability in public healthcare provision due to the Russian public healthcare financial reforms. Evidence suggests that there are substantial inter-regional inequalities across income groups both in terms of financing and access to public healthcare services. There are large efficiency differences between regions, along with inter-regional variations in payment and reimbursement mechanisms. Informal and quasi-formal payments deteriorate access to public healthcare services and undermine the overall financing sustainability. The public healthcare sector is still underfinanced, although the implementation of health insurance gave some premises for future increases of efficiency. Overall, the available empirical data are not sufficient for an evidence-based evaluation of the reforms. More studies on the quality, equity, efficiency and sustainability impact of the reforms are needed. Future reforms should focus on the implementation of cost-efficiency and cost-control mechanisms; provide incentives for better allocation and distribution of resources; tackle problems in equity in access and financing; implement a system of quality controls; and stimulate healthy competition between insurance companies. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Steam conversion of liquefied petroleum gas and methane in microchannel reactor

NASA Astrophysics Data System (ADS)

Dimov, S. V.; Gasenko, O. A.; Fokin, M. I.; Kuznetsov, V. V.

2018-03-01

This study presents experimental results of steam conversion of liquefied petroleum gas and methane in annular catalytic reactor - heat exchanger. The steam reforming was done on the Rh/Al2O3 nanocatalyst with the heat applied through the microchannel gap from the outer wall. Concentrations of the products of chemical reactions in the outlet gas mixture are measured at different temperatures of reactor. The range of channel wall temperatures at which the ratio of hydrogen and carbon oxide in the outlet mixture grows substantially is determined. Data on the composition of liquefied petroleum gas conversion products for the ratio S/C = 5 was received for different GHVS.

Electrochemical separation of hydrogen from reformate using PEM fuel cell technology

NASA Astrophysics Data System (ADS)

Gardner, C. L.; Ternan, M.

This article is an examination of the feasibility of electrochemically separating hydrogen obtained by steam reforming a hydrocarbon or alcohol source. A potential advantage of this process is that the carbon dioxide rich exhaust stream should be able to be captured and stored thereby reducing greenhouse gas emissions. Results are presented for the performance of the anode of proton exchange membrane (PEM) electrochemical cell for the separation of hydrogen from a H 2-CO 2 gas mixture and from a H 2-CO 2-CO gas mixture. Experiments were carried out using a single cell state-of-the-art PEM fuel cell. The anode was fed with either a H 2-CO 2 gas mixture or a H 2-CO 2-CO gas mixture and hydrogen was evolved at the cathode. All experiments were performed at room temperature and atmospheric pressure. With the H 2-CO 2 gas mixture the hydrogen extraction efficiency is quite high. When the gas mixture included CO, however, the hydrogen extraction efficiency is relatively poor. To improve the efficiency for the separation of the gas mixture containing CO, the effect of periodic pulsing on the anode potential was examined. Results show that pulsing can substantially reduce the anode potential thereby improving the overall efficiency of the separation process although the anode potential of the CO poisoned and pulsed cell still lies above that of an unpoisoned cell.

Secondary Waste Form Screening Test Results—THOR® Fluidized Bed Steam Reforming Product in a Geopolymer Matrix

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

Pires, Richard P.; Westsik, Joseph H.; Serne, R. Jeffrey

2011-07-14

Screening tests are being conducted to evaluate waste forms for immobilizing secondary liquid wastes from the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Plans are underway to add a stabilization treatment unit to the Effluent Treatment Facility to provide the needed capacity for treating these wastes from WTP. The current baseline is to use a Cast Stone cementitious waste form to solidify the wastes. Through a literature survey, DuraLith alkali-aluminosilicate geopolymer, fluidized-bed steam reformation (FBSR) granular product encapsulated in a geopolymer matrix, and a Ceramicrete phosphate-bonded ceramic were identified both as candidate waste forms and alternatives to the baseline.more » These waste forms have been shown to meet waste disposal acceptance criteria, including compressive strength and universal treatment standards for Resource Conservation and Recovery Act (RCRA) metals (as measured by the toxicity characteristic leaching procedure [TCLP]). Thus, these non-cementitious waste forms should also be acceptable for land disposal. Information is needed on all four waste forms with respect to their capability to minimize the release of technetium. Technetium is a radionuclide predicted to be in the secondary liquid wastes in small quantities, but the Integrated Disposal Facility (IDF) risk assessment analyses show that technetium, even at low mass, produces the largest contribution to the estimated IDF disposal impacts to groundwater.« less

High Temperature Ultrasonic Probe and Pulse-Echo Probe Mounting Fixture for Testing and Blind Alignment on Steam Pipes

NASA Technical Reports Server (NTRS)

Lih, Shyh-Shiuh (Inventor); Takano, Nobuyuki (Inventor); Lee, Hyeong Jae (Inventor); Bao, Xiaoqi (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Sherrit, Stewart (Inventor); Ostlund, Patrick N. (Inventor)

2017-01-01

A high temperature ultrasonic probe and a mounting fixture for attaching and aligning the probe to a steam pipe using blind alignment. The high temperature ultrasonic probe includes a piezoelectric transducer having a high temperature. The probe provides both transmitting and receiving functionality. The mounting fixture allows the high temperature ultrasonic probe to be accurately aligned to the bottom external surface of the steam pipe so that the presence of liquid water in the steam pipe can be monitored. The mounting fixture with a mounted high temperature ultrasonic probe are used to conduct health monitoring of steam pipes and to track the height of condensed water through the wall in real-time.

Reforming the Exhaust Passage of Low-pressure Cylinder for 330MW Steam Turbine

NASA Astrophysics Data System (ADS)

Yan, Tao; Cai, Wen; Chen, Wen; Lu, Jin; Hong-yan, Yang

2018-06-01

In concern of the velocity distribution of the exhaust passage of 330MW turbine is not uniform, which results in higher the upper temperature difference of the condenser and higher exhaust pressure. It is introduced in this article that based on mathematical simulation, steam-equalizing equipment is augmented at the exhaust area of the condenser which makes the decrease in the steam resistance, much more uniform velocity distribution, and the increase of the heat transfer coefficient. By comparison of the condenser performance test before the amending and after, the result shows that after the amending, the upper temperature difference of the condenser and the exhaust pressure decreases dramatically.

Steam Pyrolysis of Polyimides: Effects of Steam on Raw Material Recovery.

PubMed

Kumagai, Shogo; Hosaka, Tomoyuki; Kameda, Tomohito; Yoshioka, Toshiaki

2015-11-17

Aromatic polyimides (PIs) have excellent thermal stability, which makes them difficult to recycle, and an effective way to recycle PIs has not yet been established. In this work, steam pyrolysis of the aromatic PI Kapton was performed to investigate the recovery of useful raw materials. Steam pyrolysis significantly enhanced the gasification of Kapton at 900 °C, resulting in 1963.1 mL g(-1) of a H2 and CO rich gas. Simultaneously, highly porous activated carbon with a high BET surface area was recovered. Steam pyrolysis increased the presence of polar functional groups on the carbon surface. Thus, it was concluded that steam pyrolysis shows great promise as a recycling technique for the recovery of useful synthetic gases and activated carbon from PIs without the need for catalysts and organic solvents.

Syngas production by high temperature steam/CO2 coelectrolysis using solid oxide electrolysis cells.

PubMed

Chen, Xinbing; Guan, Chengzhi; Xiao, Guoping; Du, Xianlong; Wang, Jian-Qiang

2015-01-01

High temperature (HT) steam/CO2 coelectrolysis with solid oxide electrolysis cells (SOECs) using the electricity and heat generated from clean energies is an important alternative for syngas production without fossil fuel consumption and greenhouse gas emissions. Herein, reaction characteristics and the outlet syngas composition of HT steam/CO2 coelectrolysis under different operating conditions, including distinct inlet gas compositions and electrolysis current densities, are systematically studied at 800 °C using commercially available SOECs. The HT coelectrolysis process, which has comparable performance to HT steam electrolysis, is more active than the HT CO2 electrolysis process, indicating the important contribution of the reverse water-gas shift reaction in the formation of CO. The outlet syngas composition from HT steam/CO2 coelectrolysis is very sensitive to the operating conditions, indicating the feasibility of controlling the syngas composition by varying these conditions. Maximum steam and CO2 utilizations of 77% and 76% are achieved at 1.0 A cm(-2) with an inlet gas composition of 20% H2/40% steam/40% CO2.

Synthesis of highly efficient CaO-based, self-stabilizing CO2 sorbents via structure-reforming of steel slag.

PubMed

Tian, Sicong; Jiang, Jianguo; Yan, Feng; Li, Kaimin; Chen, Xuejing

2015-06-16

Capturing anthropogenic CO2 in a cost-effective and highly efficient manner is one of the most challenging issues faced by scientists today. Herein, we report a novel structure-reforming approach to convert steel slag, a cheap, abundant, and nontoxic calcium-rich industrial waste, as the only feedstock into superior CaO-based, self-stabilizing CO2 sorbents. The CO2 capture capacity of all the steel slag-derived sorbents was improved more than 10-fold compared to the raw slag, with the maximum uptake of CO2 achieving at 0.50 gCO2 gsorbent(-1). Additionally, the initial steel slag-derived sorbent could retain 0.25 gCO2 gsorbent(-1), that is, a decay rate of only 12% over 30 carbonation-calcination cycles, the excellent self-stabilizing property allowed it to significantly outperform conventional CaO, and match with most of the existing synthetic CaO-based sorbents. A synergistic effect that facilitated CO2 capture by CaO-based sorbents was clearly recognized when Mg and Al, the most common elements in steel slag, coexisted with CaO in the forms of MgO and Al2O3, respectively. During the calcium looping process, MgO served as a well spacer to increase the porosity of sorbents together with Al2O3 serving as a durable stabilizer to coresist the sintering of CaCO3 grains at high temperatures.

Thermally efficient melting and fuel reforming for glass making

DOEpatents

Chen, Michael S.; Painter, Corning F.; Pastore, Steven P.; Roth, Gary S.; Winchester, David C.

1991-01-01

An integrated process for utilizing waste heat from a glass making furnace. The hot off-gas from the furnace is initially partially cooled, then fed to a reformer. In the reformer, the partially cooled off-gas is further cooled against a hydrocarbon which is thus reformed into a synthesis gas, which is then fed into the glass making furnace as a fuel. The further cooled off-gas is then recycled back to absorb the heat from the hot off-gas to perform the initial cooling.

Prospects for the development of coal-steam plants in Russia

NASA Astrophysics Data System (ADS)

Tumanovskii, A. G.

2017-06-01

Evaluation of the technical state of the modern coal-fired power plants and quality of coal consumed by Russian thermal power plants (TPP) is provided. Measures aimed at improving the economic and environmental performance of operating 150-800 MW coal power units are considered. Ways of efficient use of technical methods of NO x control and electrostatic precipitators' upgrade for improving the efficiency of ash trapping are summarized. Examples of turbine and boiler equipment efficiency upgrading through its deep modernization are presented. The necessity of the development and introduction of new technologies in the coal-fired power industry is shown. Basic technical requirements for a 660-800 MW power unit with the steam conditions of 28 MPa, 600/600°C are listed. Design solutions taking into account features of Russian coal combustion are considered. A field of application of circulating fluidized bed (CFB) boilers and their effectiveness are indicated. The results of development of a new generation coal-fired TPP, including a steam turbine with an increased efficiency of the compartments and disengaging clutch, an elevated steam conditions boiler, and a highly efficient NO x /SO2 and ash particles emission control system are provided. In this case, the resulting ash and slag are not to be sent to the ash dumps and are to be used to a maximum advantage. Technical solutions to improve the efficiency of coal gasification combined cycle plants (CCP) are considered. A trial plant based on a 16 MW gas turbine plant (GTP) and an air-blown gasifier is designed as a prototype of a high-power CCP. The necessity of a state-supported technical reequipment and development program of operating coal-fired power units, as well as putting into production of new generation coal-fired power plants, is noted.

Ambient pressure XPS and IRRAS investigation of ethanol steam reforming on Ni–CeO 2(111) catalysts: An in situ study of C–C and O–H bond scission

DOE PAGES

Liu, Zongyuan; Duchon, Tomas; Wang, Huanru; ...

2016-03-31

Ambient-Pressure X-ray Photoelectron Spectroscopy (AP-XPS) and Infrared Reflection Absorption Spectroscopy (AP-IRRAS) have been used to elucidate the active sites and mechanistic steps associated with the ethanol steam reforming reaction (ESR) over Ni–CeO 2(111) model catalysts. Our results reveal that surface layers of the ceria substrate are both highly reduced and hydroxylated under reaction conditions while the small supported Ni nanoparticles are present as Ni 0/NixC. A multifunctional, synergistic role is highlighted in which Ni, CeO x and the interface provide an ensemble effect in the active chemistry that leads to H 2. Ni 0 is the active phase leading tomore » both C–C and C–H bond cleavage in ethanol and it is also responsible for carbon accumulation. On the other hand, CeO x is important for the deprotonation of ethanol/water to ethoxy and OH intermediates. The active state of CeO x is a Ce 3+(OH) x compound that results from extensive reduction by ethanol and the efficient dissociation of water. Additionally, we gain an important insight into the stability and selectivity of the catalyst by its effective water dissociation, where the accumulation of surface carbon can be mitigated by the increased presence of surface OH groups. As a result, the co-existence and cooperative interplay of Ni 0 and Ce 3+(OH) x through a metal–support interaction facilitate oxygen transfer, activation of ethanol/water as well as the removal of coke.« less

Thermally efficient melting and fuel reforming for glass making

DOEpatents

Chen, M.S.; Painter, C.F.; Pastore, S.P.; Roth, G.S.; Winchester, D.C.

1991-10-15

An integrated process is described for utilizing waste heat from a glass making furnace. The hot off-gas from the furnace is initially partially cooled, then fed to a reformer. In the reformer, the partially cooled off-gas is further cooled against a hydrocarbon which is thus reformed into a synthesis gas, which is then fed into the glass making furnace as a fuel. The further cooled off-gas is then recycled back to absorb the heat from the hot off-gas to perform the initial cooling. 2 figures.

Hydrogen production from coal using a nuclear heat source

NASA Technical Reports Server (NTRS)

Quade, R. N.

1976-01-01

A strong candidate for hydrogen production in the intermediate time frame of 1985 to 1995 is a coal-based process using a high-temperature gas-cooled reactor (HTGR) as a heat source. Expected process efficiencies in the range of 60 to 70% are considerably higher than all other hydrogen production processes except steam reforming of a natural gas. The process involves the preparation of a coal liquid, hydrogasification of that liquid, and steam reforming of the resulting gaseous or light liquid product. A study showing process efficiency and cost of hydrogen vs nuclear reactor core outlet temperature has been completed, and shows diminishing returns at process temperatures above about 1500 F. A possible scenario combining the relatively abundant and low-cost Western coal deposits with the Gulf Coast hydrogen users is presented which provides high-energy density transportation utilizing coal liquids and uranium.

Distillate fuel-oil processing for phosphoric acid fuel cell power plants

NASA Astrophysics Data System (ADS)

1980-02-01

Efforts to develop distillate oil steam reforming processes are reviewed, and the applicability of these processes for integration with the fuel cell are discussed. The development efforts can be grouped into the following processing approaches: high temperature steam reforming; autothermal reforming; autothermal gasification; and ultra desulfurization followed by steam reforming. Sulfur in the feed is a problem in the process development.

The Mediating Role of Textbooks in High-Stakes Assessment Reform

ERIC Educational Resources Information Center

Leung, Ching Yin; Andrews, Stephen

2012-01-01

Whenever high-stakes assessment/curriculum reforms take place, new textbooks appear on the market. These textbooks inevitably play a significant mediating role in the implementation of any reform and on teaching and learning. This paper reports on a small-scale study which attempts to investigate the role of textbooks in the mediation of a…

Combustion synthesized copper-ion substituted FeAl2O4 (Cu0.1Fe0.9Al2O4): A superior catalyst for methanol steam reforming compared to its impregnated analogue

NASA Astrophysics Data System (ADS)

Maiti, Sayantani; Llorca, Jordi; Dominguez, Montserrat; Colussi, Sara; Trovarelli, Alessandro; Priolkar, Kaustubh R.; Aquilanti, Giuliana; Gayen, Arup

2016-02-01

A series of copper ion substituted MAl2O4 (M = Mg, Mn, Fe and Zn) spinels is prepared by a single step solution combustion synthesis (SCS) and tested for methanol steam reforming (MSR). The copper ion substituted Cu0.1Fe0.9Al2O4 appears to be the most active, showing ∼98% methanol conversion at 300 °C with ∼5% CO selectivity at GHSV = 30,000 h-1 and H2O:CH3OH = 1.1. The analogous impregnated catalyst, CuO (10 at%)/FeAl2O4, is found to be much less active. These materials are characterized by XRD, H2-TPR, BET, HRTEM, XPS and XANES analyses. Spinel phase formation is highly facilitated upon Cu-ion substitution and Cu loading beyond 10 at% leads to the formation of CuO as an additional phase. The ionic substitution of copper in FeAl2O4 leads to the highly crystalline SCS catalyst containing Cu2+ ion sites that are shown to be more active than the dispersed CuO nano-crystallites on the FeAl2O4 impregnated catalyst, despite its lower surface area. The as prepared SCS catalyst contains also a portion of copper as Cu1+ that increases when subjected to reforming atmosphere. The MSR activity of the SCS catalyst decreases with time-on-stream due to the sintering of catalyst crystallites as established from XPS and HRTEM analyses.

DFT Studies of Adsorption of Cu7-atom Nanoclusters on TiO2 Surfaces and Application to Methanol Steam Reforming Reactions

NASA Astrophysics Data System (ADS)

Taft, Michael J., Sr.

Alcohol conversion to hydrogen, via steam reforming, is an alternative energy process that is promising for the future of clean energy economies. With advancements in fuel cell technologies, on-board hydrogen reforming could leverage already existing automotive designs and fuel infrastructure. The design of catalytic materials with tunable properties requires a level of insight that has yet to be achieved experimentally. The central objective of this project is to develop a working model of metal-oxide surface mediated copper clusters, since such catalytic beds have a wide-range of applications. More specifically, we investigate the catalytic framework of this process with theoretical models of the active metal (Cu) and metal­oxide support (TiO2). We employ a Density Functional Theory (DFT)-Generalized Gradient Approximation (GGA) approach for the quantum level electronic structure calculations of Cu, TiO2 and CH3OH. Additionally, we have generated anatase (A(001), A(101)) and rutile (R(100), R(110)) surface morphologies and 7­atom copper cluster complexes with those planes. To examine the possible influence of TiO2 on the adsorption properties of our active metal, Cu7, we have carried out adsorption studies with CH3OH. Our final data and observations predict that the Cu7 cluster adopts a symmetric pentagonal bipyramidal geometry with D5h symmetry. We find that the anatase morphology has a greater overall stability than rutile. The adsorption strength of the Cu7 cluster has been predicted in this study to be according to the following order: A(001) > A(101)> R(110). Indeed, the R(100) surface appears to be an unfavorable surface for metal cluster binding. Our data indicates that copper cluster stabilization on the metal-oxide surface depends on the nature of the crystal face. Again, we studied the adsorption properties of methanol on nascent Cu7 cluster, Cu7-TiO 2 complex and on pure TiO2-surface in A(001) polymorphic form. The calculations revealed that methanol

Methane steam reforming rates over Pt, Rh and Ni(111) accounting for H tunneling and for metal lattice vibrations

NASA Astrophysics Data System (ADS)

German, Ernst D.; Sheintuch, Moshe

2017-02-01

Microkinetic models of methane steam reforming (MSR) over bare platinum and rhodium (111) surfaces are analyzed in present work using calculated rate constants. The individual rate constants are classified into three different sets: (i) rate constants of adsorption and desorption steps of CH4, H2O, CO and of H2; (ii) rate constants of dissociation and formation of A-H bonds (A = C, O, and H), and (iii) rate constants of dissociation and formation of C-O bond. The rate constants of sets (i) and (iii) are calculated using transition state theory and published thermochemical data. The rate constants of H-dissociation reactions (set (ii)) are calculated in terms of a previously-developed approach that accounts for thermal metal lattice vibrations and for H tunneling through a potential barrier of height which depends on distance of AH from a surface. Pre-exponential factors of several group (ii) steps were calculated to be usually lower than the traditional kBT/h due to tunneling effect. Surface composition and overall MSR rates over platinum and rhodium surfaces are compared with those over nickel surface showing that operating conditions strongly affect on the activity order of the catalysts.

LARGE-SCALE HYDROGEN PRODUCTION FROM NUCLEAR ENERGY USING HIGH TEMPERATURE ELECTROLYSIS

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

James E. O'Brien

2010-08-01

Hydrogen can be produced from water splitting with relatively high efficiency using high-temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high-temperature process heat. When coupled to an advanced high temperature nuclear reactor, the overall thermal-to-hydrogen efficiency for high-temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. Demandmore » for hydrogen is increasing rapidly for refining of increasingly low-grade petroleum resources, such as the Athabasca oil sands and for ammonia-based fertilizer production. Large quantities of hydrogen are also required for carbon-efficient conversion of biomass to liquid fuels. With supplemental nuclear hydrogen, almost all of the carbon in the biomass can be converted to liquid fuels in a nearly carbon-neutral fashion. Ultimately, hydrogen may be employed as a direct transportation fuel in a “hydrogen economy.” The large quantity of hydrogen that would be required for this concept should be produced without consuming fossil fuels or emitting greenhouse gases. An overview of the high-temperature electrolysis technology will be presented, including basic theory, modeling, and experimental activities. Modeling activities include both computational fluid dynamics and large-scale systems analysis. We have also demonstrated high-temperature electrolysis in our laboratory at the 15 kW scale, achieving a hydrogen production rate in excess of 5500 L/hr.« less

Can Community Colleges Afford to Improve Completion? Measuring the Cost and Efficiency Consequences of Reform

ERIC Educational Resources Information Center

Belfield, Clive; Crosta, Peter; Jenkins, Davis

2014-01-01

Community colleges are under pressure to improve completion rates and efficiency despite limited economic evidence on how to do so and the consequences of different reform strategies. Here, we set out an economic model of student course pathways linked to college expenditures and revenues. Using detailed data from a single college, we calculate…

An easy “SteamDrop” method for high quality plant chromosome preparation

PubMed Central

2014-01-01

Background The chromosome preparation is a crucial step for obtaining satisfactory results in molecular cytogenetic researches. The preparation of plant chromosomes for molecular cytogenetic purposes remains a challenge for some species. In contrast to human chromosome preparation, the processes occurring during plant chromosome preparation and causing chromosome spreading are still poorly understood. Results We studied the dynamics of plant chromosome spreading after dropping cell suspension on slides. We showed that steam stimulates cytoplasm hydrolysis and rapid chromosome spreading and that chromosomes stretch during this chromosome spreading. Based on these observations, we developed a novel method, named “SteamDrop”, for the preparation of well-spread mitotic and pachytene chromosomes and successfully used it for 28 plant species with large and small chromosomes. We applied cell suspensions in ethanol instead of the commonly used ethanol/acetic acid fixative. Mitotic and meiotic chromosomes prepared via “SteamDrop” were used in fluorescent in situ hybridization (FISH) experiments with repetitive and unique DNA probes. Long storage of cell suspensions in ethanol did not impair the quality of chromosome preparations. Conclusion The SteamDrop procedure provides a robust and routine method for high quality plant chromosome preparations. The method can be applied for metaphase as well as pachytene chromosome preparation in wide range of species. The chromosomes prepared by SteamDrop are well suitable for repetitive and unique DNA visualization. PMID:24602284

Sourcing of Steam and Electricity for Carbon Capture Retrofits.

PubMed

Supekar, Sarang D; Skerlos, Steven J

2017-11-07

This paper compares different steam and electricity sources for carbon capture and sequestration (CCS) retrofits of pulverized coal (PC) and natural gas combined cycle (NGCC) power plants. Analytical expressions for the thermal efficiency of these power plants are derived under 16 different CCS retrofit scenarios for the purpose of illustrating their environmental and economic characteristics. The scenarios emerge from combinations of steam and electricity sources, fuel used in each source, steam generation equipment and process details, and the extent of CO 2 capture. Comparing these scenarios reveals distinct trade-offs between thermal efficiency, net power output, levelized cost, profit, and net CO 2 reduction. Despite causing the highest loss in useful power output, bleeding steam and extracting electric power from the main power plant to meet the CCS plant's electricity and steam demand maximizes plant efficiency and profit while minimizing emissions and levelized cost when wholesale electricity prices are below 4.5 and 5.2 US¢/kWh for PC-CCS and NGCC-CCS plants, respectively. At prices higher than these higher profits for operating CCS retrofits can be obtained by meeting 100% of the CCS plant's electric power demand using an auxiliary natural gas turbine-based combined heat and power plant.

Downhole steam generator having a downhole oxidant compressor

DOEpatents

Fox, Ronald L.

1983-01-01

Apparatus and method for generation of steam in a borehole for penetration into an earth formation wherein a downhole oxidant compressor is used to compress relatively low pressure (atmospheric) oxidant, such as air, to a relatively high pressure prior to mixing with fuel for combustion. The multi-stage compressor receives motive power through a shaft driven by a gas turbine powered by the hot expanding combustion gases. The main flow of compressed oxidant passes through a velocity increasing nozzle formed by a reduced central section of the compressor housing. An oxidant bypass feedpipe leading to peripheral oxidant injection nozzles of the combustion chamber are also provided. The downhole compressor allows effective steam generation in deep wells without need for high pressure surface compressors. Feedback preheater means are provided for preheating fuel in a preheat chamber. Preheating of the water occurs in both a water feed line running from aboveground and in a countercurrent water flow channel surrounding the combustor assembly. The countercurrent water flow channels advantageously serve to cool the combustion chamber wall. The water is injected through slotted inlets along the combustion chamber wall to provide an unstable boundary layer and stripping of the water from the wall for efficient steam generation. Pressure responsive doors are provided at the steam outlet for closing and sealing the combustion chamber from entry of reservoir fluids in the event of a flameout.

Review of the coal-fired, over-supercritical and ultra-supercritical steam power plants

NASA Astrophysics Data System (ADS)

Tumanovskii, A. G.; Shvarts, A. L.; Somova, E. V.; Verbovetskii, E. Kh.; Avrutskii, G. D.; Ermakova, S. V.; Kalugin, R. N.; Lazarev, M. V.

2017-02-01

The article presents a review of developments of modern high-capacity coal-fired over-supercritical (OSC) and ultra-supercritical (USC) steam power plants and their implementation. The basic engineering solutions are reported that ensure the reliability, economic performance, and low atmospheric pollution levels. The net efficiency of the power plants is increased by optimizing the heat balance, improving the primary and auxiliary equipment, and, which is the main thing, by increasing the throttle conditions. As a result of the enhanced efficiency, emissions of hazardous substances into the atmosphere, including carbon dioxide, the "greenhouse" gas, are reduced. To date, the exhaust steam conditions in the world power industry are p 0 ≈ 30 MPa and t 0 = 610/620°C. The efficiency of such power plants reaches 47%. The OSC plants are being operated in Germany, Denmark, Japan, China, and Korea; pilot plants are being developed in Russia. Currently, a project of a power plant for the ultra-supercritical steam conditions p 0 ≈ 35 MPa and t 0 = 700/720°C with efficiency of approximately 50% is being studied in the EU within the framework of the Thermie AD700 program, project AD 700PF. Investigations in this field have also been launched in the United States, Japan, and China. Engineering solutions are also being sought in Russia by the All-Russia Thermal Engineering Research Institute (VTI) and the Moscow Power Engineering Institute. The stated steam parameter level necessitates application of new materials, namely, nickel-base alloys. Taking into consideration high costs of nickel-base alloys and the absence in Russia of technologies for their production and manufacture of products from these materials for steam-turbine power plants, the development of power plants for steam parameters of 32 MPa and 650/650°C should be considered to be the first stage in creating the USC plants as, to achieve the above parameters, no expensive alloys are require. To develop and

Second law analysis of a conventional steam power plant

NASA Technical Reports Server (NTRS)

Liu, Geng; Turner, Robert H.; Cengel, Yunus A.

1993-01-01

A numerical investigation of exergy destroyed by operation of a conventional steam power plant is computed via an exergy cascade. An order of magnitude analysis shows that exergy destruction is dominated by combustion and heat transfer across temperature differences inside the boiler, and conversion of energy entering the turbine/generator sets from thermal to electrical. Combustion and heat transfer inside the boiler accounts for 53.83 percent of the total exergy destruction. Converting thermal energy into electrical energy is responsible for 41.34 percent of the total exergy destruction. Heat transfer across the condenser accounts for 2.89 percent of the total exergy destruction. Fluid flow with friction is responsible for 0.50 percent of the total exergy destruction. The boiler feed pump turbine accounts for 0.25 percent of the total exergy destruction. Fluid flow mixing is responsible for 0.23 percent of the total exergy destruction. Other equipment including gland steam condenser, drain cooler, deaerator and heat exchangers are, in the aggregate, responsible for less than one percent of the total exergy destruction. An energy analysis is also given for comparison of exergy cascade to energy cascade. Efficiencies based on both the first law and second law of thermodynamics are calculated for a number of components and for the plant. The results show that high first law efficiency does not mean high second law efficiency. Therefore, the second law analysis has been proven to be a more powerful tool in pinpointing real losses. The procedure used to determine total exergy destruction and second law efficiency can be used in a conceptual design and parametric study to evaluate the performance of other steam power plants and other thermal systems.

Steam sterilisation's energy and water footprint.

PubMed

McGain, Forbes; Moore, Graham; Black, Jim

2017-03-01

Objective The aim of the present study was to quantify hospital steam steriliser resource consumption to provide baseline environmental data and identify possible efficiency gains. We sought to find the amount of steriliser electricity and water used for active cycles and for idling (standby), and the relationship between the electricity and water consumption and the mass and type of items sterilised. Methods We logged a hospital steam steriliser's electricity and water meters every 5min for up to 1 year. We obtained details of all active cycles (standard 134°C and accessory or 'test' cycles), recording item masses and types. Relationships were investigated for both the weight and type of items sterilised with electricity and water consumption. Results Over 304 days there were 2173 active cycles, including 1343 standard 134°C cycles that had an average load mass of 21.2kg, with 32% of cycles <15kg. Electricity used for active cycles was 32652kWh (60% of total), whereas the water used was 1243495L (79%). Standby used 21457kWh (40%) electricity and 329200L (21%) water. Total electricity and water consumption per mass sterilised was 1.9kWhkg -1 and 58Lkg -1 , respectively. The linear regression model predicting electricity use was: kWh=15.7+ 0.14×mass (in kg; R 2 =0.58, P<0.01). Models for water and item type were poor. Electricity and water use fell from 3kWhkg -1 and 200Lkg -1 , respectively, for 5-kg loads to 0.5kWhkg -1 and 20Lkg -1 , respectively, for 40-kg loads. Conclusions Considerable electricity and water use occurred during standby, load mass was only moderately predictive of electricity consumption and light loads were common yet inefficient. The findings of the present study are a baseline for steam sterilisation's environmental footprint and identify areas to improve efficiencies. What is known about the topic? There is increasing interest in the environmental effects of healthcare. Life cycle assessment ('cradle to grave') provides a scientific

An evaluation of different steam disinfection protocols for cystic fibrosis nebulizers.

PubMed

Hohenwarter, K; Prammer, W; Aichinger, W; Reychler, G

2016-01-01

Contamination is a key element in cystic fibrosis. For this reason, nebulizer hygiene is an important, but complex and time-consuming task for cystic fibrosis patients. The aim of this study was to compare different steam disinfection and drying protocols. One hundred nebulizer parts were inoculated with cystic fibrosis-related bacteria in high concentrations (Burkholderia multivorans 3.9 × 10(10)/ml, Staphylococcus aureus 8.9 × 10(8/)ml and Pseudomonas aeruginosa 2.1 × 10(9)/ml). Tubes with Mycobacterium abscessus complex were additionally tested. Six steam disinfectors were compared. Different methods of drying were examined. All tested bacteria were efficiently killed by the different steam disinfectors tested. The risk of contamination depended on the method of drying. Steam disinfection is a safe disinfection method. It is better to leave the nebulizers wet after steam disinfection than to manipulate them by active drying, which seems to be a source of recontamination. Copyright © 2015 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Advanced steam power plant concepts with optimized life-cycle costs: A new approach for maximum customer benefit

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

Seiter, C.

1998-07-01

The use of coal power generation applications is currently enjoying a renaissance. New highly efficient and cost-effective plant concepts together with environmental protection technologies are the main factors in this development. In addition, coal is available on the world market at attractive prices and in many places it is more readily available than gas. At the economical leading edge, standard power plant concepts have been developed to meet the requirements of emerging power markets. These concepts incorporate the high technological state-of-the-art and are designed to achieve lowest life-cycle costs. Low capital cost, fuel costs and operating costs in combination withmore » shortest lead times are the main assets that make these plants attractive especially for IPPs and Developers. Other aspects of these comprehensive concepts include turnkey construction and the willingness to participate in BOO/BOT projects. One of the various examples of such a concept, the 2 x 610-MW Paiton Private Power Project Phase II in Indonesia, is described in this paper. At the technological leading edge, Siemens has always made a major contribution and was pacemaker for new developments in steam power plant technology. Modern coal-fired steam power plants use computer-optimized process and plant design as well as advanced materials, and achieve efficiencies exceeding 45%. One excellent example of this high technology is the world's largest lignite-fired steam power plant Schwarze Pumpe in Germany, which is equipped with two 800 MW Siemens steam turbine generators with supercritical steam parameters. The world's largest 50-Hz single-shaft turbine generator with supercritical steam parameters rated at 1025 MW for the Niederaussem lignite-fired steam power plant in Germany is a further example of the sophisticated Siemens steam turbine technology and sets a new benchmark in this field.« less

Dry reforming of methane to syngas: a potential alternative process for value added chemicals-a techno-economic perspective.

PubMed

Mondal, Kartick; Sasmal, Sankar; Badgandi, Srikant; Chowdhury, Dipabali Roy; Nair, Vinod

2016-11-01

During the past decade, there has been increasing global concern over the rise of anthropogenic CO 2 emission into the Earth's atmosphere (J Air Waste Manage Assoc 53:645-715, 2003). The utilization of CO 2 to produce any valuable product is need of the hour. The production of syngas from CO 2 and CH 4 seems to be one of the promising alternatives in terms of industrial utilization, as it offers several advantages: (a) mitigation of CO 2 , (b) transformation of natural gas and CO 2 into valuable syngas, and (c) producing syngas with H 2 /CO ratio 1 which may further be used for the production of valuable petrochemicals (J Air Waste Manage Assoc 53:645-715, 2003). A conceptual design for the production of synthesis gas by dry reforming of methane is presented here. An economic assessment of this process with an integrated methanol production section as a case was conceptualized and compared with the conventional steam methane reforming route to produce methanol. The economic study indicated that dry reforming of natural gas/methane is a competitive process with lower operating and capital costs in comparison with steam reforming assuming negligible cost of CO 2 import.

Steam drum design for direct steam generation

NASA Astrophysics Data System (ADS)

Willwerth, Lisa; Müller, Svenja; Krüger, Joachim; Succo, Manuel; Feldhoff, Jan Fabian; Tiedemann, Jörg; Pandian, Yuvaraj; Krüger, Dirk; Hennecke, Klaus

2017-06-01

For the direct steam generation in solar fields, the recirculation concept has been demonstrated in several installations. Water masses in the solar field vary during transient phases, such as passing clouds. The volume of the steam drum can serve as a buffer during such transients by taking in excess water and providing water storage. The saturated steam mass flow to the superheating section or the consumer can be maintained almost constant during short transients; therefore the steam drum plays a key role for constant steam supply. Its buffer effect depends on the right sizing of the steam drum for the prevailing situations. Due to missing experiences, steam drums have been sized under conservative assumptions and are thereby usually oversized. With this paper, experiences on the steam drum of the 5 MWel TSE1 power plant are discussed for optimized future plant design. The results are also of relevance for process heat installations, in which saturated steam is produced by the solar field.

Roadmap of retail electricity market reform in China: assisting in mitigating wind energy curtailment

NASA Astrophysics Data System (ADS)

Yu, Dezhao; Qiu, Huadong; Yuan, Xiang; Li, Yuan; Shao, Changzheng; Lin, You; Ding, Yi

2017-01-01

Among the renewable energies, wind energy has gained the rapidest development in China. Moreover wind power generation has been penetrated into power system in a large scale. However, the high level wind curtailment also indicates a low efficiency of wind energy utilization over the last decade in China. One of the primary constraints on the utilization of wind energy is the lack of an electricity market, in which renewable energies can compete equally with traditional fossil fuel generation. Thus the new round electric power industry reform is essential in China. The reform involves implementing new pricing mechanism, introducing retail-side competition, promoting the consumption of renewable energy. The new round reform can be a promising solution for promoting the development and consumption of wind energy generation in China. Based on proposed reform policies of electric power industry, this paper suggests a roadmap for retail electricity market reform of China, which consists of three stages. Barriers to the efficient utilization of wind energy are also analysed. Finally, this paper introduces several efficient measures for mitigating wind curtailment in each stage of reform.

A novel hybrid organosolv: steam explosion method for the efficient fractionation and pretreatment of birch biomass.

PubMed

Matsakas, Leonidas; Nitsos, Christos; Raghavendran, Vijayendran; Yakimenko, Olga; Persson, Gustav; Olsson, Eva; Rova, Ulrika; Olsson, Lisbeth; Christakopoulos, Paul

2018-01-01

The main role of pretreatment is to reduce the natural biomass recalcitrance and thus enhance saccharification yield. A further prerequisite for efficient utilization of all biomass components is their efficient fractionation into well-defined process streams. Currently available pretreatment methods only partially fulfill these criteria. Steam explosion, for example, excels as a pretreatment method but has limited potential for fractionation, whereas organosolv is excellent for delignification but offers poor biomass deconstruction. In this article, a hybrid method combining the cooking and fractionation of conventional organosolv pretreatment with the implementation of an explosive discharge of the cooking mixture at the end of pretreatment was developed. The effects of various pretreatment parameters (ethanol content, duration, and addition of sulfuric acid) were evaluated. Pretreatment of birch at 200 °C with 60% v/v ethanol and 1% w/w biomass H 2 SO 4 was proven to be the most efficient pretreatment condition yielding pretreated solids with 77.9% w/w cellulose, 8.9% w/w hemicellulose, and 7.0 w/w lignin content. Under these conditions, high delignification of 86.2% was demonstrated. The recovered lignin was of high purity, with cellulose and hemicellulose contents not exceeding 0.31 and 3.25% w/w, respectively, and ash to be < 0.17% w/w in all cases, making it suitable for various applications. The pretreated solids presented high saccharification yields, reaching 68% at low enzyme load (6 FPU/g) and complete saccharification at high enzyme load (22.5 FPU/g). Finally, simultaneous saccharification and fermentation (SSF) at 20% w/w solids yielded an ethanol titer of 80 g/L after 192 h, corresponding to 90% of the theoretical maximum. The novel hybrid method developed in this study allowed for the efficient fractionation of birch biomass and production of pretreated solids with high cellulose and low lignin contents. Moreover, the explosive

Does Small High School Reform Lift Urban Districts? Evidence from New York City

ERIC Educational Resources Information Center

Stiefel, Leanna; Schwartz, Amy Ellen; Wiswall, Matthew

2015-01-01

Research finds that small high schools deliver better outcomes than large high schools for urban students. An important outstanding question is whether this better performance is gained at the expense of losses elsewhere: Does small school reform lift the whole district? We explore New York City's small high school reform in which hundreds of new…

Radial Microchannel Reactor (RMR) used in Steam Reforming CH4

DTIC Science & Technology

2013-05-13

process on land and at sea will reduce CO2 emission and enable cost reductions in the generation of energy in many small market economies. Peter R...size of GTL process on land and at sea will reduce CO2 emission and enable cost reductions in the generation of energy in many small market ...distribution of a 3.3:1 steam-methane mixture at 750 °C and 11 bar is: H2 45.8%, H2O 36.99%, CO 6.365%, CO2 6.681% and CH4 4.14% Barring any coking , this

Evaluation Findings from High School Reform Efforts in Baltimore

ERIC Educational Resources Information Center

Smerdon, Becky; Cohen, Jennifer

2009-01-01

The Baltimore City Public School System (BCPSS) is one of the first urban districts in the country to undertake large-scale high school reform, phasing in small learning communities by opening new high schools and transforming large, comprehensive high schools into small high schools. With support from the Bill & Melinda Gates Foundation, a…

Application of CaO-Based Bed Material for Dual Fluidized Bed Steam Biomass Gasification

NASA Astrophysics Data System (ADS)

Koppatz, S.; Pfeifer, C.; Kreuzeder, A.; Soukup, G.; Hofbauer, H.

Gasification of biomass is a suitable option for decentralized energy supply based on renewable sources in the range of up to 50 MW fuel input. The paper presents the dual fluidized bed (DFB) steam gasification process, which is applied to generate high quality and nitrogen-free product gas. Essential part of the DFB process is the bed material used in the fluidized reactors, which has significant impact on the product gas quality. By the use of catalytically active bed materials the performance of the overall process is increased, since the bed material favors reactions of the steam gasification. In particular, tar reforming reactions are favored. Within the paper, the pilot plant based on the DFB process with 100kW fuel input at Vienna University of Technology, Austria is presented. Actual investigations with focus on CaO-based bed materials (limestone) as well as with natural olivine as bed material were carried out at the pilot plant. The application of CaO-based bed material shows mainly decreased tar content in the product gas in contrast to experiments with olivine as bed material. The paper presents the results of steam gasification experiments with limestone and olivine, whereby the product gas composition as well as the tar content and the tar composition are outlined.

Teacher Union Contracts and High School Reform

ERIC Educational Resources Information Center

Price, Mitch

2009-01-01

Are teachers unions and collective bargaining agreements barriers to high school reform and redesign efforts in Washington, California, and Ohio? The short answer: sometimes, but not as often as many educators seem to think. Rather than wade into the pro- versus anti-union debate, this report instead aims to offer guidance for educators, unions,…

Features of steam turbine cooling by the example of an SKR-100 turbine for supercritical steam parameters

NASA Astrophysics Data System (ADS)

Arkadyev, B. A.

2015-10-01

Basic principles of cooling of high-temperature steam turbines and constructive solutions used for development of the world's first cooled steam turbine SKR-100 (R-100-300) are described. Principal differences between the thermodynamic properties of cooling medium in the steam and gas turbines and the preference of making flow passes of cooled cylinders of steam turbines as reactive are shown. Some of its operation results and their conclusions are given. This turbine with a power of 100 MW, initial steam parameters approximately 30 MPa and 650°C, and back pressure 3 MPa was made by a Kharkov turbine plant in 1961 and ran successfully at a Kashira GRES (state district power plant) up to 1979, when it was taken out of use in a still fully operating condition. For comparison, some data on construction features and operation results of the super-high pressure cylinder of steam turbines of American Philo 6 (made by General Electric Co.) and Eddystone 1 (made by Westinghouse Co.) power generating units, which are close to the SKR-100 turbine by design initial steam parameters and the implementation time, are given. The high operational reliability and effectiveness of the cooling system that was used in the super-high pressure cylinder of the SKR-100 turbine of the power-generating unit, which were demonstrated in operation, confirms rightfulness and expediency of principles and constructive solutions laid at its development. As process steam temperatures are increased, the realization of the proposed approach to cooling of multistage turbines makes it possible to limit for large turbine parts the application of new, more expensive high-temperature materials, which are required for making steam boilers, and, in some cases, to do completely away with their utilization.

Study of connected system of automatic control of load and operation efficiency of a steam boiler with extremal controller on a simulation model

NASA Astrophysics Data System (ADS)

Sabanin, V. R.; Starostin, A. A.; Repin, A. I.; Popov, A. I.

2017-02-01

The problems of operation effectiveness increase of steam boilers are considered. To maintain the optimum fuel combustion modes, it is proposed to use an extremal controller (EC) determining the value of airflow rate, at which the boiler generating the desired amount of heat will consume a minimum amount of fuel. EC sets the determined value of airflow rate to airflow rate controller (ARC). The test results of numerical simulation dynamic nonlinear model of steam boiler with the connected system of automatic control of load and combustion efficiency using EC are presented. The model is created in the Simulink modeling package of MATLAB software and can be used to optimize the combustion modes. Based on the modeling results, the conclusion was drawn about the possibility in principle of simultaneously boiler load control and optimizing by EC the combustion modes when changing the fuel combustion heat and the boiler characteristics and its operating mode. It is shown that it is possible to automatically control the operation efficiency of steam boilers when using EC without applying the standard flue gas analyzers. The article considers the numerical simulation dynamic model of steam boiler with the schemes of control of fuel consumption and airflow rate, the steam pressure and EC; the purpose of using EC in the scheme with linear controllers and the requirements to the quality of its operation; the results of operation of boiler control schemes without EC with estimation of influence of roughness of thermal mode maps on the nature of static and dynamic connection of the control units of fuel consumption and airflow rate; the phase trajectories and the diagrams of transient processes occurring in the control scheme with EC with stepped changing the fuel quality and boiler characteristics; analysis of modeling results and prospects for using EC in the control schemes of boilers.

Steam jet mill-a prospective solution to industrial exhaust steam and solid waste.

PubMed

Zhang, Mingxing; Chen, Haiyan

2018-04-20

Bulk industrial solid wastes occupy a lot of our resources and release large amounts of toxic and hazardous substances to the surrounding environment, demanding innovative strategies for grinding, classification, collection, and recycling for economically ultrafine powder. A new technology for grinding, classification, collection, and recycling solid waste is proposed, using the superheated steam produced from the industrial exhaust steam to disperse, grind, classify, and collect the industrial solid waste. A large-scale steam jet mill was designed to operate at an inlet steam temperature 230-300 °C and an inlet pressure of 0.2-0.6 MPa. A kind of industrial solid waste fluidized-bed combustion ashes was used to grinding tests at different steam temperatures and inlet pressures. The total process for grinding, classification, and collection is drying. Two kinds of particle sizes are obtained. One particle size is d 50  = 4.785 μm, and another particle size is d 50  = 8.999 μm. For particle size d 50  = 8.999 μm, the inlet temperature is 296 °C and an inlet pressure is 0.54 MPa for the grinding chamber. The steam flow is 21.7 t/h. The yield of superfine powder is 73 t/h. The power consumption is 3.76 kW h/t. The obtained superfine powder meets the national standard S95 slag. On the basis of these results, a reproducible and sustainable industrial ecological protocol using steam produced by industrial exhaust heat coupled to solid waste recycling is proposed, providing an efficient, large-scale, low-cost, promising, and green method for both solid waste recovery and industrial exhaust heat reutilization.

Four Rs for Urban High School Reform: Re-Envisioning, Reculturation, Restructuring, and Remoralization

ERIC Educational Resources Information Center

Hemmings, Annette

2012-01-01

A framework for urban public high school reform is presented for managing site-based change through re-envisioning, reculturation, restructuring, and remoralization. The four Rs for reform framework is elucidated through a qualitative study of a low-performing urban public high school that was transformed into a new more successful school. The…

High efficiency Brayton cycles using LNG

DOEpatents

Morrow, Charles W [Albuquerque, NM

2006-04-18

A modified, closed-loop Brayton cycle power conversion system that uses liquefied natural gas as the cold heat sink media. When combined with a helium gas cooled nuclear reactor, achievable efficiency can approach 68 76% (as compared to 35% for conventional steam cycle power cooled by air or water). A superheater heat exchanger can be used to exchange heat from a side-stream of hot helium gas split-off from the primary helium coolant loop to post-heat vaporized natural gas exiting from low and high-pressure coolers. The superheater raises the exit temperature of the natural gas to close to room temperature, which makes the gas more attractive to sell on the open market. An additional benefit is significantly reduced costs of a LNG revaporization plant, since the nuclear reactor provides the heat for vaporization instead of burning a portion of the LNG to provide the heat.

[On the importance of the steam trap to the efficient sterilization of solutions in stored blood bottles by saturated steam under pressure (author's transl)].

PubMed

Schreiber, M; Göbel, M

1979-01-01

Biological tests with soil samples were performed to fix the sterilization time for a new steam sterilizer. These tests yielded repeatedly positive spore findings despite modifications of the conditions of sterilization. Having excluded a series of possible sources of trouble, the authors stated that the quality of the steam was the assignable cause. After restoration of the functionality of the steam traps, the biological tests yielded negative results also under normal conditions of sterilization.

CFD analysis of a solid oxide fuel cell with internal reforming: Coupled interactions of transport, heterogeneous catalysis and electrochemical processes

NASA Astrophysics Data System (ADS)

Janardhanan, Vinod M.; Deutschmann, Olaf

Direct internal reforming in solid oxide fuel cell (SOFC) results in increased overall efficiency of the system. Present study focus on the chemical and electrochemical process in an internally reforming anode supported SOFC button cell running on humidified CH 4 (3% H 2 O). The computational approach employs a detailed multi-step model for heterogeneous chemistry in the anode, modified Butler-Volmer formalism for the electrochemistry and Dusty Gas Model (DGM) for the porous media transport. Two-dimensional elliptic model equations are solved for a button cell configuration. The electrochemical model assumes hydrogen as the only electrochemically active species. The predicted cell performances are compared with experimental reports. The results show that model predictions are in good agreement with experimental observation except the open circuit potentials. Furthermore, the steam content in the anode feed stream is found to have remarkable effect on the resulting overpotential losses and surface coverages of various species at the three-phase boundary.

Review of surface steam sterilization for validation purposes.

PubMed

van Doornmalen, Joost; Kopinga, Klaas

2008-03-01

Sterilization is an essential step in the process of producing sterile medical devices. To guarantee sterility, the process of sterilization must be validated. Because there is no direct way to measure sterility, the techniques applied to validate the sterilization process are based on statistical principles. Steam sterilization is the most frequently applied sterilization method worldwide and can be validated either by indicators (chemical or biological) or physical measurements. The steam sterilization conditions are described in the literature. Starting from these conditions, criteria for the validation of steam sterilization are derived and can be described in terms of physical parameters. Physical validation of steam sterilization appears to be an adequate and efficient validation method that could be considered as an alternative for indicator validation. Moreover, physical validation can be used for effective troubleshooting in steam sterilizing processes.

Hydrogen generation from biogenic and fossil fuels by autothermal reforming

NASA Astrophysics Data System (ADS)

Rampe, Thomas; Heinzel, Angelika; Vogel, Bernhard

Hydrogen generation for fuel cell systems by reforming technologies from various fuels is one of the main fields of investigation of the Fraunhofer ISE. Suitable fuels are, on the one hand, gaseous hydrocarbons like methane, propane but also, on the other hand, liquid hydrocarbons like gasoline and alcohols, e.g., ethanol as biogenic fuel. The goal is to develop compact systems for generation of hydrogen from fuel being suitable for small-scale membrane fuel cells. The most recent work is related to reforming according to the autothermal principle — fuel, air and steam is supplied to the reactor. Possible applications of such small-scale autothermal reformers are mobile systems and also miniature fuel cell as co-generation plant for decentralised electricity and heat generation. For small stand-alone systems without a connection to the natural gas grid liquid gas, a mixture of propane and butane is an appropriate fuel.

Use of bauxite as packing material in steam injection wells

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

Scoglio, J.; Joubert, G.; Gallardo, B.

1995-12-31

Cyclic steam injection, also known as steam soak, has proven to be the most efficient method for producing heavy crude oil and bitumen from unconsolidated sands. The application of steam injection may, however, generate sand production, causing, among other things, a decrease in production. The gravel pack technique is the most efficient way to prevent fines production from cold producing wells. But, once they are steam stimulated, a dissolution of quartz containing gravel material takes place reducing greatly the packing permeability and eventually sand production. Different types of packing material have been used to avoid sand production after cyclic steammore » injection, such as gravel, ceramics, bauxite, coated resin, and American sand. This paper presents the results of field test, using sinterized bauxite as a packing material, carried out in Venezuela`s heavy oil operations as a part of a comprehensive program aimed at increasing the packing durability and reducing sand production. This paper also verify the results of laboratory tests in which Bauxite was found to be less soluble than other packing material when steam injected.« less

PARTIAL ECONOMIC STUDY OF STEAM COOLED HEAVY WATER MODERATED REACTORS

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

None

1960-04-01

Steam-cooled reactors are compared with CAHDU for costs of Calandria tubes, pressure tubes. heavy water moderator, heavy water reflector, fuel supply, heat exchanger, and turbine generator. A direct-cycle lightsteam-cooled heavy- water-moderated pressure-tube reactor formed the basic reactor design for the study. Two methods of steam circulation through the reactor were examined. In both cases the steam was generated outside the reactor and superheated in the reactor core. One method consisted of a series of reactor and steam generator passes. The second method consisted of the Loeffler cycle and its modifications. The fuel was assumed to be natural cylindrical UO/sub 2/more » pellets sheathed in a hypothetical material with the nuclear properties of Zircaloy, but able to function at temperatures to 900 deg F. For the conditions assumed, the longer the rod, the higher the outlet temperature and therefore the higher the efficiency. The turbine cycle efficiency was calculated on the assumption that suitable steam generators are available. As the neutron losses to the pressure tubes were significant, an economic analysis of insulated pressure tubes is included. A description of the physics program for steam-cooled reactors is included. Results indicated that power from the steam-cooled reactor would cost 1.4 mills/ kwh compared with 1.25 mills/kwh for CANDU. (M.C.G.)« less

Teaching and Learning Conditions Improve High School Reform Efforts

ERIC Educational Resources Information Center

Center for Teaching Quality, 2007

2007-01-01

The North Carolina high school reform movement is focused on creating small, personalized and academically rigorous schools that increase graduation rates, reduce suspension and expulsion rates, increase college going rates and reduce college remediation rates. This report indicates that redesigned and early college high schools in North Carolina…

University Governance Reforms: Potential Problems of More Autonomy?

ERIC Educational Resources Information Center

Christensen, Tom

2011-01-01

University governance reforms are very much a reflection of the broader New Public Management reforms that are focusing on increasing efficiency in public organizations. The article deals with how university reform ideas of a generic nature, emphasizing that universities should be treated and reformed like any other public organizations, are…

Improve Your Boiler's Combustion Efficiency: Office of Industrial Technologies (OIT) Steam Energy Tips No.4

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

Not Available

2002-03-01

Operating your boiler with an optimum amount of excess air will minimize heat loss up the stack and improve combustion efficiency. Combustion efficiency is a measure of how effectively the heat content of a fuel is transferred into usable heat. The stack temperature and flue gas oxygen (or carbon dioxide) concentrations are primary indicators of combustion efficiency. Given complete mixing, a precise or stoichiometric amount of air is required to completely react with a given quantity of fuel. In practice, combustion conditions are never ideal, and additional or ''excess'' air must be supplied to completely burn the fuel. The correctmore » amount of excess air is determined from analyzing flue gas oxygen or carbon dioxide concentrations. Inadequate excess air results in unburned combustibles (fuel, soot, smoke, and carbon monoxide) while too much results in heat lost due to the increased flue gas flow--thus lowering the overall boiler fuel-to-steam efficiency. The table relates stack readings to boiler performance. On well-designed natural gas-fired systems, an excess air level of 10% is attainable. An often stated rule of thumb is that boiler efficiency can be increased by 1% for each 15% reduction in excess air or 40 F reduction in stack gas temperature.« less

Analysis of Korean Elementary Pre-Service Teachers' Changing Attitudes about Integrated STEAM Pedagogy through Developing Lesson Plans

ERIC Educational Resources Information Center

Kim, Dongryeul; Bolger, Molly

2017-01-01

Integrated curricula have become a major educational focus in Korea. Policy changes began in 2009 when the Korea Ministry of Education, Science, and Technology announced a new curriculum incorporating Science, Technology, Engineering, Arts, and Mathematics (STEAM). Various stages of educational reform have occurred since that time. This study…

Impact of the Local Public Hospital Reform on the Efficiency of Medium-Sized Hospitals in Japan: An Improved Slacks-Based Measure Data Envelopment Analysis Approach.

PubMed

Zhang, Xing; Tone, Kaoru; Lu, Yingzhe

2018-04-01

To assess the change in efficiency and total factor productivity (TFP) of the local public hospitals in Japan after the local public hospital reform launched in late 2007, which was aimed at improving the financial capability and operational efficiency of hospitals. Secondary data were collected from the Ministry of Internal Affairs and Communications on 213 eligible medium-sized hospitals, each operating 100-400 beds from FY2006 to FY2011. The improved slacks-based measure nonoriented data envelopment analysis models (Quasi-Max SBM nonoriented DEA models) were used to estimate dynamic efficiency score and Malmquist Index. The dynamic efficiency measure indicated an efficiency gain in the first several years of the reform and then was followed by a decrease. Malmquist Index analysis showed a significant decline in the TFP between 2006 and 2011. The financial improvement of medium-sized hospitals was not associated with enhancement of efficiency. Hospital efficiency was not significantly different among ownership structure and law-application system groups, but it was significantly affected by hospital location. The results indicate a need for region-tailored health care policies and for a more comprehensive reform to overcome the systemic constraints that might contribute to the decline of the TFP. © Health Research and Educational Trust.

Health care reform and changes: the Malaysian experience.

PubMed

Merican, Mohd Ismail; bin Yon, Rohaizat

2002-01-01

Health care reform is an intentional, sustained and systematic process of structural change to one or more health subsystems to improve efficiency, effectiveness, patient choices and equity. Health care all over the world is continuously reforming with time. Health care reform has become an increasingly important agenda for policy change in both developed and developing countries including Malaysia. This paper provides an overview of the Malaysian health care system, its achievements, and issues and challenges leading to ongoing reform towards a more efficient and equitable health care system that possess a better quality of life for the population.

Elucidating the interaction between Ni and CeO x in ethanol steam reforming catalysts: A perspective of recent studies over model and powder systems

DOE PAGES

Liu, Zongyuan; Senanayake, Sanjaya D.; Rodriguez, Jose A.

2016-11-15

Bulk metallic nickel is a poor catalyst for the reforming of oxygenates being deactivated by the deposition of coke. In contrast, Ni-ceria is an active system for the catalytic extraction of H 2 from the ethanol steam reforming reaction (ESR, C 2H 5OH + 3H 2O ↔ 2CO 2 + 6H 2). Numerous studies, with model (well-defined crystal surfaces) and technical (high surface area powders) catalysts, have been devoted to understand the fundamental role of each catalyst component, the performance of adjacent sites in the metal-oxide interface, and the complex mechanistic steps that convert two oxygenated reactants (ethanol and Hmore » 2O) into H 2. The size and low loading of Ni on ceria facilitate metal-oxide support interactions that probably enhance the reactivity of the system. To establish the precise role of both Ni and Ce is challenging. However it is clear that both Ni and Ce are associated with the dissociation of H 2O (OH + H), while ceria readily adsorbs and partially dissociates ethanol (i.e. ethoxy formation). The most difficult step of Csingle bondC bond dissociation likely occurs only on Ni or at the Ni-Ce interface. H 2O and OH remain as important agents for the prevention of excess C build up during the Csingle bondH/Csingle bondC dissociation process. Often, deactivation upon C build up, is a direct result of Ni sintering and decoupling of the Ni-Ce interactions. One strategy to maintain good activity and stability is to protect the Ni-Ce interaction, and this can be achieved through the use of solid solutions (Ce 1–xNi xO 2–y) or by employing stabilizing agents such as W (Ni xW yCe zO 2). In this paper, we present and discuss the most recent work for the ESR reaction and show the important role of ceria which participates directly in the reaction and also enhances catalytic activity through metal-support interactions.« less

Extremely Black Vertically Aligned Carbon Nanotube Arrays for Solar Steam Generation.

PubMed

Yin, Zhe; Wang, Huimin; Jian, Muqiang; Li, Yanshen; Xia, Kailun; Zhang, Mingchao; Wang, Chunya; Wang, Qi; Ma, Ming; Zheng, Quan-Shui; Zhang, Yingying

2017-08-30

The unique structure of a vertically aligned carbon nanotube (VACNT) array makes it behave most similarly to a blackbody. It is reported that the optical absorptivity of an extremely black VACNT array is about 0.98-0.99 over a large spectral range of 200 nm-200 μm, inspiring us to explore the performance of VACNT arrays in solar energy harvesting. In this work, we report the highly efficient steam generation simply by laminating a layer of VACNT array on the surface of water to harvest solar energy. It is found that under solar illumination the temperature of upper water can significantly increase with obvious water steam generated, indicating the efficient solar energy harvesting and local temperature rise by the thin layer of VACNTs. We found that the evaporation rate of water assisted by VACNT arrays is 10 times that of bare water, which is the highest ratio for solar-thermal-steam generation ever reported. Remarkably, the solar thermal conversion efficiency reached 90%. The excellent performance could be ascribed to the strong optical absorption and local temperature rise induced by the VACNT layer, as well as the ultrafast water transport through the VACNT layer due to the frictionless wall of CNTs. Based on the above, we further demonstrated the application of VACNT arrays in solar-driven desalination.

Advanced waste management technology evaluation

NASA Technical Reports Server (NTRS)

Couch, H.; Birbara, P.

1996-01-01

The purpose of this program is to evaluate the feasibility of steam reforming spacecraft wastes into simple recyclable inorganic salts, carbon dioxide and water. Model waste compounds included cellulose, urea, methionine, Igapon TC-42, and high density polyethylenes. These are compounds found in urine, feces, hygiene water, etc. The gasification and steam reforming process used the addition of heat and low quantities of oxygen to oxidize and reduce the model compounds.The studied reactions were aimed at recovery of inorganic residues that can be recycled into a closed biologic system. Results indicate that even at very low concentrations of oxygen (less than 3%) the formation of a carbonaceous residue was suppressed. The use of a nickel/cobalt reforming catalyst at reaction temperature of 1600 degrees yielded an efficient destruction of the organic effluents, including methane and ammonia. Additionally, the reforming process with nickel/cobalt catalyst diminished the noxious odors associated with butyric acid, methionine and plastics.

Thermo-electrochemical production of compressed hydrogen from methane with near-zero energy loss

NASA Astrophysics Data System (ADS)

Malerød-Fjeld, Harald; Clark, Daniel; Yuste-Tirados, Irene; Zanón, Raquel; Catalán-Martinez, David; Beeaff, Dustin; Morejudo, Selene H.; Vestre, Per K.; Norby, Truls; Haugsrud, Reidar; Serra, José M.; Kjølseth, Christian

2017-11-01

Conventional production of hydrogen requires large industrial plants to minimize energy losses and capital costs associated with steam reforming, water-gas shift, product separation and compression. Here we present a protonic membrane reformer (PMR) that produces high-purity hydrogen from steam methane reforming in a single-stage process with near-zero energy loss. We use a BaZrO3-based proton-conducting electrolyte deposited as a dense film on a porous Ni composite electrode with dual function as a reforming catalyst. At 800 °C, we achieve full methane conversion by removing 99% of the formed hydrogen, which is simultaneously compressed electrochemically up to 50 bar. A thermally balanced operation regime is achieved by coupling several thermo-chemical processes. Modelling of a small-scale (10 kg H2 day-1) hydrogen plant reveals an overall energy efficiency of >87%. The results suggest that future declining electricity prices could make PMRs a competitive alternative for industrial-scale hydrogen plants integrating CO2 capture.

Let's make a deal: trading malpractice reform for health reform.

PubMed

Sage, William M; Hyman, David A

2014-01-01

Physician leadership is required to improve the efficiency and reliability of the US health care system, but many physicians remain lukewarm about the changes needed to attain these goals. Malpractice liability-a sore spot for decades-may exacerbate physician resistance. The politics of malpractice have become so lawyer-centric that recognizing the availability of broader gains from trade in tort reform is an important insight for health policy makers. To obtain relief from malpractice liability, physicians may be willing to accept other policy changes that more directly improve access to care and reduce costs. For example, the American Medical Association might broker an agreement between health reform proponents and physicians to enact federal legislation that limits malpractice liability and simultaneously restructures fee-for-service payment, heightens transparency regarding the quality and cost of health care services, and expands practice privileges for other health professionals. There are also reasons to believe that tort reform can make ongoing health care delivery reforms work better, in addition to buttressing health reform efforts that might otherwise fail politically.

Radioactive Demonstration Of Mineralized Waste Forms Made From Hanford Low Activity Waste (Tank SX-105, Tank AN-103, And AZ-101/102) By Fluidized Bed Steam Reformation (FBSR)

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

Jantzen, C. M.; Crawford, C. L.; Bannochie, C. J.

Fluidized Bed Steam Reforming (FBSR) is a robust technology for the immobilization of a wide variety of radioactive wastes. Applications have been tested at the pilot scale for the high sodium, sulfate, halide, organic and nitrate wastes at the Hanford site, the Idaho National Laboratory (INL), and the Savannah River Site (SRS). Due to the moderate processing temperatures, halides, sulfates, and technetium are retained in mineral phases of the feldspathoid family (nepheline, sodalite, nosean, carnegieite, etc). The feldspathoid minerals bind the contaminants such as Tc-99 in cage (sodalite, nosean) or ring (nepheline) structures to surrounding aluminosilicate tetrahedra in the feldspathoidmore » structures. The granular FBSR mineral waste form that is produced has a comparable durability to LAW glass based on the short term PCT testing in this study, the INL studies, SPFT and PUF testing from previous studies as given in the columns in Table 1-3 that represent the various durability tests. Monolithing of the granular product was shown to be feasible in a separate study. Macro-encapsulating the granular product provides a decrease in leaching compared to the FBSR granular product when the geopolymer is correctly formulated.« less

Dry reforming of methane on a highly-active Ni-CeO 2 catalyst: Effects of metal-support interactions on C–H bond breaking

DOE PAGES

Liu, Zongyuan; Grinter, David C.; Lustemberg, Pablo G.; ...

2016-05-04

Ni-CeO 2 is a highly efficient, stable and non-expensive catalyst for methane dry reforming at relative low temperatures (700 K). The active phase of the catalyst consists of small nanoparticles of nickel dispersed on partially reduced ceria. Experiments of ambient pressure XPS indicate that methane dissociates on Ni/CeO 2 at temperatures as low as 300 K, generating CH x and CO x species on the surface of the catalyst. Strong metal–support interactions activate Ni for the dissociation of methane. The results of density-functional calculations show a drop in the effective barrier for methane activation from 0.9 eV on Ni(111) tomore » only 0.15 eV on Ni/CeO 2–x(111). At 700 K, under methane dry reforming conditions, no signals for adsorbed CH x or C species are detected in the C1s XPS region. As a result, the reforming of methane proceeds in a clean and efficient way.« less

Bio-Fuel Production Assisted with High Temperature Steam Electrolysis

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

Grant Hawkes; James O'Brien; Michael McKellar

2012-06-01

Two hybrid energy processes that enable production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure are presented. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), these two hybrid energy processes have the potential to provide a significant alternative petroleum source that could reduce dependence on imported oil. The first process discusses a hydropyrolysis unit with hydrogen addition from HTSE. Non-food biomass is pyrolyzed and converted to pyrolysis oil. The pyrolysis oil is upgraded with hydrogen addition from HTSE. This addition of hydrogen deoxygenates the pyrolysis oilmore » and increases the pH to a tolerable level for transportation. The final product is synthetic crude that could then be transported to a refinery and input into the already used transportation fuel infrastructure. The second process discusses a process named Bio-Syntrolysis. The Bio-Syntrolysis process combines hydrogen from HTSE with CO from an oxygen-blown biomass gasifier that yields syngas to be used as a feedstock for synthesis of liquid synthetic crude. Conversion of syngas to liquid synthetic crude, using a biomass-based carbon source, expands the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A

Hydrogen-oxygen steam generator applications for increasing the efficiency, maneuverability and reliability of power production

NASA Astrophysics Data System (ADS)

Schastlivtsev, A. I.; Borzenko, V. I.

2017-11-01

The comparative feasibility study of the energy storage technologies showed good applicability of hydrogen-oxygen steam generators (HOSG) based energy storage systems with large-scale hydrogen production. The developed scheme solutions for the use of HOSGs for thermal power (TPP) and nuclear power plants (NPP), and the feasibility analysis that have been carried out have shown that their use makes it possible to increase the maneuverability of steam turbines and provide backup power supply in the event of failure of the main steam generating equipment. The main design solutions for the integration of hydrogen-oxygen steam generators into the main power equipment of TPPs and NPPs, as well as their optimal operation modes, are considered.

Bridging the Gap: From Model Surfaces to Nanoparticle Analogs for Selective Oxidation and Steam Reforming of Methanol and Selective Hydrogenation Catalysis

NASA Astrophysics Data System (ADS)

Boucher, Matthew B.

Most industrial catalysts are very complex, comprising of non-uniform materials with varying structures, impurities, and interaction between the active metal and supporting substrate. A large portion of the ongoing research in heterogeneous catalysis focuses on understanding structure-function relationships in catalytic materials. In parallel, there is a large area of surface science research focused on studying model catalytic systems for which structural parameters can be tuned and measured with high precision. It is commonly argued, however, that these systems are oversimplified, and that observations made in model systems do not translate to robust catalysts operating in practical environments; this discontinuity is often referred to as a "gap." The focus of this thesis is to explore the mutual benefits of surface science and catalysis, or "bridge the gap," by studying two catalytic systems in both ultra-high vacuum (UHV) and near ambient-environments. The first reaction is the catalytic steam reforming of methanol (SRM) to hydrogen and carbon dioxide. The SRM reaction is a promising route for on-demand hydrogen production. For this catalytic system, the central hypothesis in this thesis is that a balance between redox capability and weak binding of reaction intermediates is necessary for high SRM activity and selectivity to carbon dioxide. As such, a new catalyst for the SRM reaction is developed which incorporates very small amounts of gold (<1 atomic %) supported on zinc oxide nanoparticles with controlled crystal structures. The performance of these catalysts was studied in a fixed-bed micro-reactor system at ambient pressures, and their structure was characterized by high-resolution microscopic and spectroscopic techniques. Pre-existing oxygen defects in zinc oxide {0001} surfaces, and those created by a perturbation of the defect equilibrium by addition of gold, provide an anchoring site for highly dispersed gold species. By utilizing shape control of

Articulation between High School and CEGEP Science Post-Reform: Understanding the Gap

ERIC Educational Resources Information Center

McPherson, Heather; McDonnell, Maggie

2017-01-01

Reforms in K-12 science education are global. New national science curricula were introduced in the United States (NRC, 1996), in Canada (CEMC, 1997), and in Europe (European Commission 2007). In this article, the impact of these reforms on college students in Quebec is studied. Articulation between high school and college sectors is viewed…

High pressure autothermal reforming in low oxygen environments

NASA Astrophysics Data System (ADS)

Reese, Mark A.; Turn, Scott Q.; Cui, Hong

Recent interest in fuel cells has led to the conceptual design of an ocean floor, fuel cell-based, power generating station fueled by methane from natural gas seeps or from the controlled decomposition of methane hydrates. Because the dissolved oxygen concentration in deep ocean water is too low to provide adequate supplies to a fuel processor and fuel cell, oxygen must be stored onboard the generating station. A lab scale catalytic autothermal reformer capable of operating at pressures of 6-50 bar was constructed and tested. The objective of the experimental program was to maximize H 2 production per mole of O 2 supplied (H 2(out)/O 2(in)). Optimization, using oxygen-to-carbon (O 2/C) and water-to-carbon (S/C) ratios as independent variables, was conducted at three pressures using bottled O 2. Surface response methodology was employed using a 2 2 factorial design. Optimal points were validated using H 2O 2 as both a stored oxidizer and steam source. The optimal experimental conditions for maximizing the moles of H 2(out)/O 2(in) occurred at a S/C ratio of 3.00-3.35 and an O 2/C ratio of 0.44-0.48. When using H 2O 2 as the oxidizer, the moles of H 2(out)/O 2(in) increased ≤14%. An equilibrium model was also used to compare experimental and theoretical results.

The influence of nano-architectured CeOx supports in RhPd/CeO₂ for the catalytic ethanol steam reforming reaction

DOE PAGES

Divins, N. J.; Senanayake, S. D.; Casanovas, A.; ...

2015-01-19

The ethanol steam reforming (ESR) reaction has been tested over RhPd supported on polycrystalline ceria in comparison to structured supports composed of nanoshaped CeO₂ cubes and CeO₂ rods tailored towards the production of hydrogen. At 650-700 K the hydrogen yield follows the trend RhPd/CeO₂-cubes > RhPd/CeO₂ -rods > RhPd/CeO₂- polycrystalline, whereas at temperatures higher than 800 K the catalytic performance of all samples is similar and close to the thermodynamic equilibrium. The improved performance of RhPd/CeO₂-cubes and RhPd/CeO₂ -rods for ESR at low temperature is mainly ascribed to higher water-gas shift activity and a strong interaction between the bimetallic -more » oxide support interaction. STEM analysis shows the existence of RhPd alloyed nanoparticles in all samples, with no apparent relationship between ESR performance and RhPd particle size. X-ray diffraction under operating conditions shows metal reorganization on {100} and {110} ceria crystallographic planes during catalyst activation and ESR, but not on {111} ceria crystallographic planes. The RhPd reconstructing and tuned activation over ceria nanocubes and nanorods is considered the main reason for better catalytic activity with respect to conventional catalysts based on polycrystalline ceria« less

Beyond Changing Culture in Small High Schools: Reform Models and Changing Instruction with Project-Based Learning

ERIC Educational Resources Information Center

Ravitz, Jason

2010-01-01

This study describes the status of small school reforms in U.S. high schools and contemplates their future. It asks how cultural and instructional reforms differ across school reform types. Analyses focus on indicators of teacher and student culture as well as instructional reforms including project-based learning (PBL) and other inquiry-related…

Radioactive Demonstration Of Mineralized Waste Forms Made From Hanford Low Activity Waste (Tank SX-105 And AN-103) By Fluidized Bed Steam Reformation

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

Jantzen, Carol; Herman, Connie; Crawford, Charles

One of the immobilization technologies under consideration as a Supplemental Treatment for Hanford’s Low Activity Waste (LAW) is Fluidized Bed Steam Reforming (FBSR). The FBSR technology forms a mineral waste form at moderate processing temperatures thus retaining and atomically bonding the halides, sulfates, and technetium in the mineral phases (nepheline, sodalite, nosean, carnegieite). Additions of kaolin clay are used instead of glass formers and the minerals formed by the FBSR technology offers (1) atomic bonding of the radionuclides and constituents of concern (COC) comparable to glass, (2) short and long term durability comparable to glass, (3) disposal volumes comparable tomore » glass, and (4) higher Na2O and SO{sub 4} waste loadings than glass. The higher FBSR Na{sub 2}O and SO{sub 4} waste loadings contribute to the low disposal volumes but also provide for more rapid processing of the LAW. Recent FBSR processing and testing of Hanford radioactive LAW (Tank SX-105 and AN-103) waste is reported and compared to previous radioactive and non-radioactive LAW processing and testing.« less

"Twin copper source" growth of metal-organic framework membrane: Cu(3)(BTC)(2) with high permeability and selectivity for recycling H(2).

PubMed

Guo, Hailing; Zhu, Guangshan; Hewitt, Ian J; Qiu, Shilun

2009-02-11

In this communication, the copper net supported Cu(3)(BTC)(2) membranes have been successfully synthesized by means of a "twin copper source" technique. Separation studies on gaseous mixtures (H(2)/CO(2), H(2)/CH(4), and H(2)/N(2)) using the membrane revealed that the membrane possesses high permeability and selectivity for H(2) over CO(2), N(2), and CH(4). Compared with the conventional zeolite membranes, the copper net supported Cu(3)(BTC)(2) membrane exhibited high permeation flux in gas separation. Such highly efficient copper net supported Cu(3)(BTC)(2) membranes could be used to separate, recycle, and reuse H(2) exhausted from steam reforming natural gas.

Root cause analysis of oxide scale forming and shedding in high temperature reheater of a 200MW super high pressure boiler

NASA Astrophysics Data System (ADS)

Bo, Jiang; Hao, Weidong; Hu, Zhihong; Liu, Fuguo

2015-12-01

In order to solve the problem of over temperature tube-burst caused by oxide scale shedding and blocking tubes of high temperature reheater of a 200MW super high pressure power plant boiler, this paper expounds the mechanism of scale forming and shedding, and analyzes the probable causes of the tube-burst failure. The results show that the root cause of scale forming is that greater steam extraction flow after reforming of the second extraction leads to less steam flow into reheater, which causes over temperature to some of the heated tubes; and the root cause of scale shedding is that long term operation in AGC-R mode brings about great fluctuations of unit load, steam temperature and pressure, accelerating scale shedding. In conclusion, preventive measures are drawn up considering the operation mode of the unit.

Steam explosion and its combinatorial pretreatment refining technology of plant biomass to bio-based products.

PubMed

Chen, Hong-Zhang; Liu, Zhi-Hua

2015-06-01

Pretreatment is a key unit operation affecting the refinery efficiency of plant biomass. However, the poor efficiency of pretreatment and the lack of basic theory are the main challenges to the industrial implementation of the plant biomass refinery. The purpose of this work is to review steam explosion and its combinatorial pretreatment as a means of overcoming the intrinsic characteristics of plant biomass, including recalcitrance, heterogeneity, multi-composition, and diversity. The main advantages of the selective use of steam explosion and other combinatorial pretreatments across the diversity of raw materials are introduced. Combinatorial pretreatment integrated with other unit operations is proposed as a means to exploit the high-efficiency production of bio-based products from plant biomass. Finally, several pilot- and demonstration-scale operations of the plant biomass refinery are described. Based on the principle of selective function and structure fractionation, and multi-level and directional composition conversion, an integrated process with the combinatorial pretreatments of steam explosion and other pretreatments as the core should be feasible and conform to the plant biomass refinery concept. Combinatorial pretreatments of steam explosion and other pretreatments should be further exploited based on the type and intrinsic characteristics of the plant biomass used, the bio-based products to be made, and the complementarity of the processes. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Formation of inclusion complexes between high amylose starch and octadecyl ferulate via steam jet cooking.

PubMed

Kenar, James A; Compton, David L; Little, Jeanette A; Peterson, Steve C

2016-04-20

Amylose-ligand inclusion complexes represent an interesting approach to deliver bioactive molecules. However, ferulic acid has been shown not to form single helical inclusion complexes with amylose from high amylose maize starch. To overcome this problem a lipophilic ferulic acid ester, octadecyl ferulate, was prepared and complexed with amylose via excess steam jet cooking. Jet-cooking octadecyl ferulate and high amylose starch gave an amylose-octadecyl ferulate inclusion complex in 51.0% isolated yield. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) confirmed that a 61 V-type inclusion complex was formed. Amylose and extraction assays showed the complex to be enriched in amylose (91.9±4.3%) and contain 70.6±5.6mgg(-1) octadecyl ferulate, although, minor hydrolysis (∼4%) of the octadecyl ferulate was observed under the excess steam jet-cooking conditions utilized. This study demonstrates that steam jet cooking is a rapid and scalable process in which to prepare amylose-octadecyl ferulate inclusion complexes. Published by Elsevier Ltd.

Antioxidants from steamed used tea leaves and their reaction behavior.

PubMed

Nomizu, Kayoko; Hashida, Koh; Makino, Rei; Ohara, Seiji

2008-07-01

The most efficient steaming conditions below 200 degrees C for extracting antioxidants from used tea leaves and their reaction behavior during the steaming treatment were investigated. The antioxidative activity of the steamed extracts increased with increasing steaming temperature, and the yield of the ethyl acetate extract fraction from each steamed extract showing the greatest antioxidative activity also increased. Caffeine, (-)-catechin, (-)-epicatechin, (-)-gallocatechin, (-)-epigallocatechin, (-)-catechin gallate, (-)-epicatechin gallate, (-)-gallocatechin gallate, (-)-epigallocatechin gallate and gallic acid were identified from the ethyl acetate extract fraction. Quantitative analyses demonstrated that the catechins with a 2,3-cis configuration decreased with increasing steaming temperature, whereas the corresponding epimers at the C-2 position increased. Each pair of epimers showed similar antioxidative activity to each other, indicating that the epimerization reaction did not contribute to the improved antioxidative activity. It is concluded from these results that the improvement in antioxidative activity at higher steaming temperatures was due to the increased yield of catechins and other antioxidants.

Apparatus and methods for supplying auxiliary steam in a combined cycle system

DOEpatents

Gorman, William G.; Carberg, William George; Jones, Charles Michael

2002-01-01

To provide auxiliary steam, a low pressure valve is opened in a combined cycle system to divert low pressure steam from the heat recovery steam generator to a header for supplying steam to a second combined cycle's steam turbine seals, sparging devices and cooling steam for the steam turbine if the steam turbine and gas turbine lie on a common shaft with the generator. Cooling steam is supplied the gas turbine in the combined cycle system from the high pressure steam turbine. Spent gas turbine cooling steam may augment the low pressure steam supplied to the header by opening a high pressure valve whereby high and low pressure steam flows are combined. An attemperator is used to reduce the temperature of the combined steam in response to auxiliary steam flows above a predetermined flow and a steam header temperature above a predetermined temperature. The auxiliary steam may be used to start additional combined cycle units or to provide a host unit with steam turbine cooling and sealing steam during full-speed no-load operation after a load rejection.

Fuel Cell/Reformers Technology Development

NASA Technical Reports Server (NTRS)

2004-01-01

NASA Glenn Research Center is interested in developing Solid Oxide Fuel Cell for use in aerospace applications. Solid oxide fuel cell requires hydrogen rich feed stream by converting commercial aviation jet fuel in a fuel processing process. The grantee's primary research activities center on designing and constructing a test facility for evaluating injector concepts to provide optimum feeds to fuel processor; collecting and analyzing literature information on fuel processing and desulfurization technologies; establishing industry and academic contacts in related areas; providing technical support to in-house SOFC-based system studies. Fuel processing is a chemical reaction process that requires efficient delivery of reactants to reactor beds for optimum performance, i.e., high conversion efficiency and maximum hydrogen production, and reliable continuous operation. Feed delivery and vaporization quality can be improved by applying NASA's expertise in combustor injector design. A 10 KWe injector rig has been designed, procured, and constructed to provide a tool to employ laser diagnostic capability to evaluate various injector concepts for fuel processing reactor feed delivery application. This injector rig facility is now undergoing mechanical and system check-out with an anticipated actual operation in July 2004. Multiple injector concepts including impinging jet, venturi mixing, discrete jet, will be tested and evaluated with actual fuel mixture compatible with reforming catalyst requirement. Research activities from September 2002 to the closing of this collaborative agreement have been in the following areas: compiling literature information on jet fuel reforming; conducting autothermal reforming catalyst screening; establishing contacts with other government agencies for collaborative research in jet fuel reforming and desulfurization; providing process design basis for the build-up of injector rig facility and individual injector design.

Career and Technical Education Reforms and Comprehensive School Reforms in High Schools: Their Impact on Education Outcomes for At-Risk Youth. The Highlight Zone: Research @ Work.

ERIC Educational Resources Information Center

Castellano, Marisa; Stringfield, Samuel; Stone, James R., III

The impact of career and technical education (CTE) reforms and comprehensive school reforms in high schools on education outcomes for at-risk youth was examined in a review of research on current reforms. The review identified a series of individual, family and home, school, and community factors that can place students at risk of failing to…

Optimization of NaOH-catalyzed steam pretreatment of empty fruit bunch.

PubMed

Choi, Won-Il; Park, Ji-Yeon; Lee, Joon-Pyo; Oh, You-Kwan; Park, Yong Chul; Kim, Jun Seok; Park, Jang Min; Kim, Chul Ho; Lee, Jin-Suk

2013-11-29

Empty fruit bunch (EFB) has many advantages, including its abundance, the fact that it does not require collection, and its year-round availability as a feedstock for bioethanol production. But before the significant costs incurred in ethanol production from lignocellulosic biomass can be reduced, an efficient sugar fractionation technology has to be developed. To that end, in the present study, an NaOH-catalyzed steam pretreatment process was applied in order to produce ethanol from EFB more efficiently. The EFB pretreatment conditions were optimized by application of certain pretreatment variables such as, the NaOH concentrations in the soaking step and, in the steam step, the temperature and time. The optimal conditions were determined by response surface methodology (RSM) to be 3% NaOH for soaking and 160°C, 11 min 20 sec for steam pretreatment. Under these conditions, the overall glucan recovery and enzymatic digestibility were both high: the glucan and xylan yields were 93% and 78%, respectively, and the enzymatic digestibility was 88.8% for 72 h using 40 FPU/g glucan. After simultaneous saccharification and fermentation (SSF), the maximum ethanol yield and concentration were 0.88 and 29.4 g/l respectively. Delignification (>85%) of EFB was an important factor in enzymatic hydrolysis using CTec2. NaOH-catalyzed steam pretreatment, which can remove lignin efficiently and requires only a short reaction time, was proven to be an effective pretreatment technology for EFB. The ethanol yield obtained by SSF, the key parameter determining the economics of ethanol, was 18% (w/w), equivalent to 88% of the theoretical maximum yield, which is a better result than have been reported in the relevant previous studies.

Optimization of NaOH-catalyzed steam pretreatment of empty fruit bunch

PubMed Central

2013-01-01

Background Empty fruit bunch (EFB) has many advantages, including its abundance, the fact that it does not require collection, and its year-round availability as a feedstock for bioethanol production. But before the significant costs incurred in ethanol production from lignocellulosic biomass can be reduced, an efficient sugar fractionation technology has to be developed. To that end, in the present study, an NaOH-catalyzed steam pretreatment process was applied in order to produce ethanol from EFB more efficiently. Results The EFB pretreatment conditions were optimized by application of certain pretreatment variables such as, the NaOH concentrations in the soaking step and, in the steam step, the temperature and time. The optimal conditions were determined by response surface methodology (RSM) to be 3% NaOH for soaking and 160°C, 11 min 20 sec for steam pretreatment. Under these conditions, the overall glucan recovery and enzymatic digestibility were both high: the glucan and xylan yields were 93% and 78%, respectively, and the enzymatic digestibility was 88.8% for 72 h using 40 FPU/g glucan. After simultaneous saccharification and fermentation (SSF), the maximum ethanol yield and concentration were 0.88 and 29.4 g/l respectively. Conclusions Delignification (>85%) of EFB was an important factor in enzymatic hydrolysis using CTec2. NaOH-catalyzed steam pretreatment, which can remove lignin efficiently and requires only a short reaction time, was proven to be an effective pretreatment technology for EFB. The ethanol yield obtained by SSF, the key parameter determining the economics of ethanol, was 18% (w/w), equivalent to 88% of the theoretical maximum yield, which is a better result than have been reported in the relevant previous studies. PMID:24286374

Save Energy Now (SEN) Assessment Helps Expand Energy Management Program at Shaw Industries: Flooring Company Saves $872,000 Annually by Improving Steam System Efficiency

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

Not Available

This case study describes how the Shaw Industries plant #20 in Dalton, Georgia, achieved annual savings of $872,000 and 93,000 MMBtu after receiving a DOE Save Energy Now energy assessment and implementing recommendations to improve the efficiency of its steam system.

Thermal Modeling and Management of Solid Oxide Fuel Cells Operating with Internally Reformed Methane

NASA Astrophysics Data System (ADS)

Wu, Yiyang; Shi, Yixiang; Cai, Ningsheng; Ni, Meng

2018-06-01

A detailed three-dimensional mechanistic model of a large-scale solid oxide fuel cell (SOFC) unit running on partially pre-reformed methane is developed. The model considers the coupling effects of chemical and electrochemical reactions, mass transport, momentum and heat transfer in the SOFC unit. After model validation, parametric simulations are conducted to investigate how the methane pre-reforming ratio affects the transport and electrochemistry of the SOFC unit. It is found that the methane steam reforming reaction has a "smoothing effect", which can achieve more uniform distributions of gas compositions, current density and temperature among the cell plane. In the case of 1500 W/m2 power density output, adding 20% methane absorbs 50% of internal heat production inside the cell, reduces the maximum temperature difference inside the cell from 70 K to 22 K and reduces the cathode air supply by 75%, compared to the condition of completely pre-reforming of methane. Under specific operating conditions, the pre-reforming ratio of methane has an optimal range for obtaining a good temperature distribution and good cell performance.

Arbiters of Effectiveness and Efficiency: The Frames and Strategies of Management Consulting Firms in US Higher Education Reform

ERIC Educational Resources Information Center

McClure, Kevin R.

2017-01-01

A growing number of public colleges and universities in the United States have hired management consulting firms to help develop strategies aimed at increasing institutional effectiveness and efficiency. The purpose of this paper is to explore the frames and strategies of consultants in US public higher education reform efforts. Drawing upon a…

Technical Feasible Study for Future Solar Thermal Steam Power Station in Malaysia

NASA Astrophysics Data System (ADS)

Bohari, Z. H.; Atira, N. N.; Jali, M. H.; Sulaima, M. F.; Izzuddin, T. A.; Baharom, M. F.

2017-10-01

This paper proposed renewable energy which is potential to be used in Malaysia in generating electricity to innovate and improve current operating systems. Thermal and water act as the resources to replace limited fossil fuels such as coal which is still widely used in energy production nowadays. Thermal is also known as the heat energy while the water absorbs energy from the thermal to produce steam energy. By combining both of the sources, it is known as thermal steam renewable energy. The targeted area to build this power station has constant high temperature and low humidity which can maximize the efficiency of generating power.

Big bang health care reform--does it work?: the case of Britain's 1991 National Health Service reforms.

PubMed

Klein, R

1995-01-01

The costs and benefits are examined of one of the very few examples of a government driving through health care reform in the face of near unanimous opposition: Britain's 1991 reforms of the National Health Service (NHS), which sought to inject the dynamics of a market into the framework of a universal, tax-financed service. The political costs to the government have been high. The public continues to see the NHS through the eyes of disgruntled doctors and nurses. The benefits, measured in efficiency gains or service improvements, are as yet difficult to establish. However, the NHS has changed in key respects. The balance has shifted from hospital specialists to general practitioners and from providers to purchasers, with increasing emphasis on professional accountability and consumerism. But the NHS continues to evolve as it strives to resolve the tensions implicit in the reforms, and the only certainty is that no future government can return to the pre-1991 situation.

Effect of steam addition on cycle performance of simple and recuperated gas turbines

NASA Technical Reports Server (NTRS)

Boyle, R. J.

1979-01-01

Results are presented for the cycle efficiency and specific power of simple and recuperated gas turbine cycles in which steam is generated and used to increase turbine flow. Calculations showed significant improvements in cycle efficiency and specific power by adding steam. The calculations were made using component efficiencies and loss assumptions typical of stationary powerplants. These results are presented for a range of operating temperatures and pressures. Relative heat exchanger size and the water use rate are also examined.

Downhole steam generator having a downhole oxidant compressor

DOEpatents

Fox, R.L.

1981-01-07

Am improved apparatus is described for the downhole injection of steam into boreholes, for tertiary oil recovery. It includes an oxidant supply, a fuel supply, an igniter, a water supply, an oxidant compressor, and a combustor assembly. The apparatus is designed for efficiency, preheating of the water, and cooling of the combustion chamber walls. The steam outlet to the borehole is provided with pressure-responsive doors for closing the outlet in response to flameout. (DLC)

Perspectives: parity--prelude to a fifth cycle of reform.

PubMed

Goldman, Howard H

2002-09-01

Based on 2000 Carl Taube Lecture at the NIMH Mental Health Economics Meeting. This perspective article examines the relationship between a policy of parity in financing mental health services and the future of reform in service delivery. Applying theories of static and dynamic efficiency to an understanding of parity and the evolution of mental health services, drawing upon Burton Weisbrod s concept of the health care quadrilemma . Each of four cycles of reform in mental health services have contended with issues of static and dynamic efficiency. Each cycle was associated with static efficiency in the management and financing of services, and each was associated with a set of new treatment technologies intended to improve dynamic efficiency. Each reform proved ultimately unsuccessful primarily because of the failure of the treatment technologies to prevent future patient chronicity or to achieve sustained recovery. Recent advances in treatment technology and management of care can permit an unprecedented level of efficiency consistent with a policy of improved access to mainstream health and social welfare resources, including insurance coverage. This policy of so-called financing parity can improve current mental health service delivery, but it may also portend a future fifth cycle of reform. If new technologies continue to advance as full technologies - simple to deliver and producing true recovery - and mainstream resources are made available, then the specialty mental health services may contract dramatically in favor of effective care and treatment of mental illness in primary care and other mainstream settings. Predicting the future of health care is speculative, but it may be easier using the Weisbrod formulation to understand the process of mental health reform. Over-reliance on administrative techniques for building static efficiency and false optimism about dynamic efficiency from new technology have stymied previous reforms. All the same, a fifth cycle

Mechanistic Insights of Ethanol Steam Reforming over Ni–CeO x (111): The Importance of Hydroxyl Groups for Suppressing Coke Formation

DOE PAGES

Liu, Zongyuan; Duchoň, Tomáš; Wang, Huanru; ...

2015-07-30

We have studied the reaction of ethanol and water over Ni–CeO 2-x(111) model surfaces to elucidate the mechanistic steps associated with the ethanol steam reforming (ESR) reaction. Our results provide insights about the importance of hydroxyl groups to the ESR reaction over Ni-based catalysts. Systematically, we have investigated the reaction of ethanol on Ni–CeO 2-x(111) at varying Ce³⁺ concentrations (CeO 1.8–2.0) with absence/presence of water using a combination of soft X-ray photoelectron spectroscopy (sXPS) and temperature-programmed desorption (TPD). Consistent with previous reports, upon annealing, metallic Ni formed on reduced ceria while NiO was the main component on fully oxidized ceria.more » Ni⁰ is the active phase leading to both the C–C and C–H cleavage of ethanol but is also responsible for carbon accumulation or coking. We have identified a Ni₃C phase that formed prior to the formation of coke. At temperatures above 600K, the lattice oxygen from ceria and the hydroxyl groups from water interact cooperatively in the removal of coke, likely through a strong metal–support interaction between nickel and ceria that facilitates oxygen transfer.« less

On high suppression of NO x and CO emissions in gas-turbine plants with combined gas-and-steam cycles

NASA Astrophysics Data System (ADS)

Ivanov, A. A.; Ermakov, A. N.; Shlyakhov, R. A.

2010-12-01

In this work are given results of analyzing processes of production of nitrogen oxides (NO x ) and afterburning of CO when firing natural gas at combined-cycle gas-turbine plants. It is shown that for suppressing emissions of the said microcomponents it is necessary to lower temperature in hot local zones of the flame in which NOx is formed, and, in so doing, to avoid chilling of cold flame zones that prevents afterburning of CO. The required lowering of the combustion temperature can be provided by combustion of mixtures of methane with steam, with high mixing uniformity that ensures the same and optimum fraction of the steam "ballast" in each microvolume of the flame. In addition to chilling, the steam ballast makes it possible to maintain a fairly high concentration of hydroxil radicals in the flame zone as well, and this provides high burning out of fuel and reduction in carbon monoxide emissions (active steam ballast). Due to this fact the fraction of steam when firing its mixtures with methane in a gas-turbine plant can be increased up to the weight ratio 4: 1. In this case, the concentrations of NO x and CO in emissions can be reduced to ultra-low values (less than 3 ppm).

Bio-ethanol, a suitable fuel to produce hydrogen for a molten carbonate fuel cell

NASA Astrophysics Data System (ADS)

Frusteri, Francesco; Freni, Salvatore

Catalytic and technological aspects in the use of bio-ethanol as fuel to produce hydrogen in both internal (IR-MCFC) and indirect internal reforming (IIR-MCFC) configurations have been considered. In MCFC conditions, even operating at total ethanol conversion, hydrogen productivity depends on the catalyst efficiency to convert methane formed through a mechanism, which foresees as first step the dehydrogenation of ethanol to acetaldehyde and as a second step the decomposition of acetaldehyde to CO and CH 4. Potassium doped Ni/MgO, Ni/La 2O 3 and Rh/MgO resulted to be the most promising catalysts to be used for the hydrogen production by steam reforming of bio-ethanol. Coke formation represents a serious problem, however, it can be drastically depressed by adding to the reaction stream a low amount of oxygen. On the basis of catalytic and technological evaluations, indirect internal reforming configuration should be the more suitable to operate with bio-ethanol. MCFC electric performance using a hydrogen rich gas coming from steam reforming of bio-ethanol is very similar to that of MCFC fed with pure hydrogen. However, the high content of steam in the flow reaction stream must be careful computed for a good thermal balance of the overall plant.

4. STEAM PLANT MARINE BOILERS WEST OF STEAM PLANT AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. STEAM PLANT MARINE BOILERS WEST OF STEAM PLANT AND SOUTH OF ORIGINAL STEAM PLANT BOILERS, FROM SOUTH. November 13, 1990 - Crosscut Steam Plant, North side Salt River near Mill Avenue & Washington Street, Tempe, Maricopa County, AZ