Science.gov

Sample records for fluid catalytic cracking

  1. Recycling of polymer waste with fluid catalytic cracking catalysts.

    PubMed

    Ali, Salmiaton; Garforth, Arthur; Fakhru'l-Razi, A

    2006-01-01

    Feedstock recycling of high-density polyethylene (HDPE) over fluid catalytic cracking (FCC) catalysts (1:6 ratio) was carried out using a laboratory fluidized bed reactor operating at 450 degrees C. Fresh and steam deactivated commercial FCC catalysts with different levels of rare earth oxide (REO) were compared as well as used FCC catalysts (E-Cats) with different levels of metal poisoning. Fresh FCC catalysts gave the highest results of HDPE degradation in terms of yield of volatile hydrocarbon product. Meanwhile, steamed FCC catalysts and used FCC catalysts showed similar but lower yields. Overall, the product yields from HDPE cracking showed that the level of metal contamination (nickel and vanadium) did not affect the product stream generated from polymer cracking. This study gives promising results as an alternative technique for the cracking and recycling of polymer waste. PMID:16760091

  2. Extending the use of fluid catalytic cracking

    SciTech Connect

    Schlossman, M.; Yen, L.C. ); Parker, W.A.

    1994-02-01

    Recently, a test program was performed in the FCC pilot plant at the M.W. Kellogg Technology Development Center that explored the effects of process variables on the yields and molecular compositions of naphthas at conditions of interest for reformulated gasoline production. The primary objective of the study was to generate yield data and detailed product characterization of cat-cracked naphthas for use in enhancing and extending existing databases. These databases will be used to develop new models and test existing ones for predicting the properties of gasolines made with different catalyst types, feed characteristics, operating temperatures, and process severities. A second objective was to validate the ability to predict octanes from analyses made on very small samples. Additionally, for Shell's samples, added emphasis was placed on the effect of gasoline endpoint. The FCC pilot plant is reclaiming a leading role in process design and development as the need for additional detailed yield and product quality data, encompassing higher conversions and operating temperatures, is driven by the requirements of reformulated fuels. The new pilot-plant data described here extends the existing databases. They provide quantitative information on detailed gasoline properties and iso-olefins yields. Because of the systematic planning of the experiments, the results can be analyzed to show the individual effects of many important independent variables. These data are being utilized to further enhance the existing kinetic correlations on FCC yields and product properties.

  3. Fluid catalytic cracking hits 50 year mark on the run

    SciTech Connect

    Reichle, A.D.

    1992-05-18

    As we approach the fiftieth anniversary of the start-up of the first commercial fluid catalytic cracker, it seems appropriate that we examine some of the background and details of that auspicious event and how it came about. Not only was this the birth of what rapidly became the world's major refining process, but also the beginning of fluidization technology that reached outside the oil industry. This paper reports on the advantages of a fluidized bed, with or without circulation, over fixed-bed, gas/solid contacting that were quickly recognized within the chemical industry. And practical applications, particularly as a chemical reactor, were soon developed in diverse areas other than catalytic cracking. By 1956, over 500 U.S. patent applications for fluidized bed processes had been granted. By 1967, fluidized reactors were in commercial use for naphtha hydroforming, fluid coking, coal carbonization, coal coking, chemicals production iron ore reduction, roasting of sulfide ores, limestone calcination, uranium processing, and other processes. Fluidization continues today as a major component of chemical engineering technology, with a steady stream of improved understanding of this complex operation, new developments, and commercial operations.

  4. Refiners discuss fluid catalytic cracking at technology meeting

    SciTech Connect

    1995-04-24

    At the National Petroleum Refiners Association`s question and answer session on refining and petrochemical technology, engineers and technical specialists from around the world gather each year to exchange experience and information on refining and petrochemical issues. Fluid catalytic cracking (FCC) catalysts were a topic of great interest at the most recent NPRA Q and A session, held Oct. 11--13, 1994, in Washington, DC. The discussions of FCC catalysts included questions about: reduction of olefins in FCC naphtha; tolerance of FCC catalysts to oxygen enrichment; use of mild hydrocracking catalyst in an FCC feed hydrotreater. At this renowned meeting, a panel of industry representatives answers presubmitted questions. Moderator and NPRA technical director Terrence S. Higgins then invites audience members to respond or ask additional questions on the subjects under discussion. This paper presents the discussions of the above three topics.

  5. Development Of Simulation Model For Fluid Catalytic Cracking

    NASA Astrophysics Data System (ADS)

    Ghosh, Sobhan

    2010-10-01

    Fluid Catalytic Cracking (FCC) is the most widely used secondary conversion process in the refining industry, for producing gasoline, olefins, and middle distillate from heavier petroleum fractions. There are more than 500 units in the world with a total processing capacity of about 17 to 20% of the crude capacity. FCC catalyst is the highest consumed catalyst in the process industry. On one hand, FCC is quite flexible with respect to it's ability to process wide variety of crudes with a flexible product yield pattern, and on the other hand, the interdependence of the major operating parameters makes the process extremely complex. An operating unit is self balancing and some fluctuations in the independent parameters are automatically adjusted by changing the temperatures and flow rates at different sections. However, a good simulation model is very useful to the refiner to get the best out of the process, in terms of selection of the best catalyst, to cope up with the day to day changing of the feed quality and the demands of different products from FCC unit. In addition, a good model is of great help in designing the process units and peripherals. A simple empirical model is often adequate to monitor the day to day operations, but they are not of any use in handling the other problems such as, catalyst selection or, design / modification of the plant. For this, a kinetic based rigorous model is required. Considering the complexity of the process, large number of chemical species undergoing "n" number of parallel and consecutive reactions, it is virtually impossible to develop a simulation model based on the kinetic parameters. The most common approach is to settle for a semi empirical model. We shall take up the key issues for developing a FCC model and the contribution of such models in the optimum operation of the plant.

  6. Fluid catalytic cracking catalyst for reformulated gasolines: Kinetic modeling

    SciTech Connect

    Gianetto, A. ); Farag, H.I. . Dept. of Chemical Engineering); Blasetti, A.P. . Dept. de Procesos); Lasa, H.I. de . Faculty of Engineering Science)

    1994-12-01

    Changes of the relative importance of intradiffusion on USY zeolite crystals were studied as a way of affecting selectivity of catalytic cracking reactions. Zeolite crystals were synthesized (Si/Al = 2.4), activated and stabilized using ion exchange and steam calcination to obtain USSY (Ultra Stable Submicron Y) zeolites. After the activation the zeolites were pelletized (45--60 [mu]m particles). USSYs were tested in a novel Riser Simulator. Results obtained show that total aromatics (BTX), benzene, C[sub 4] olefins, and coke were significantly affected with the change of zeolite crystal sizes. Gasolines produced with USSY zeolites contain less aromatics and particularly lower benzene levels. Experimental results were analyzed with a model including several lumps: unconverted gas oil, gasoline, light gases, and coke. This model also accounts for catalyst deactivation as a function of coke on catalyst. Various kinetic parameters were determined with their corresponding spans for the 95% level of confidence.

  7. Fischer-Tropsch indirect coal liquefaction design/economics-mild hydrocracking vs. fluid catalytic cracking

    SciTech Connect

    Choi, G.N.; Kramer, S.J.; Tam, S.S.; Reagan, W.J.

    1996-12-31

    In order to evaluate the economics of Fischer-Tropsch (F-T) indirect coal liquefaction, conceptual plant designs and detailed cost estimates were developed for plants producing environmentally acceptable, high-quality, liquid transportation fuels meeting the Clean Air Act requirements. The designs incorporate the latest developments in coal gasification technology and advanced (F-T) slurry reactor design. In addition, an ASPEN Plus process simulation model was developed to predict plant material and energy balances, utility requirements, operating and capital costs at varying design conditions. This paper compares mild hydrocracking and fluid catalytic cracking as alternative methods for upgrading the F-T wax.

  8. Upgrading naphtha in a multiple riser fluid catalytic cracking operation employing a catalyst mixture

    SciTech Connect

    Herbst, J.A.; Owen, H.; Schipper, P.H.

    1989-05-16

    A process is described for producing gasoline comprising contacting a hydrocarbon feed having an initial boiling-point of at least 400/sup 0/F., a 50% boiling of at least 500/sup 0/F. and an end boiling point of at least 600/sup 0/F., in a first riser, with a two component catalyst under fluid catalytic cracking conditions. At least one component of the catalyst is stripped in a stripping unit to remove entrained hydrocarbons, and regenerated wherein the two component catalyst comprises a first catalyst component selected from the group consisting of an amorphous cracking catalyst and a large pore cracking catalyst, whereby a product comprising olefins and naphtha is produced. Ethylene introduced together with the two component catalyst to a second riser, for contacting ethylene with a second catalyst component which is a shape selective medium pore crystalline silicate zeolite to produce products heavier than ethylene and to increase the temperature of the catalyst to an optimum temperature for upgrading naphtha; and naphtha is introduced to the second riser, down stream of the point of ethylene introduction, for contact with the catalyst at the optimum temperature and the naphtha is upgraded to gasoline product.

  9. Pseudocomponent test of the relative utilization of feed components in fluid catalytic cracking

    SciTech Connect

    Harding, R.H.; Gatte, R.R.; Pereira, C.J. )

    1993-03-01

    A pseudocomponent mixture is used to test the relative reactivity of hydrocarbon classes over a range of zeolite catalysts (USY, CREY, Beta, Omega, and ZSM-5) under industrial fluid catalytic cracking (FCC) conditions. The hydrocarbon mixture (32.7% n-hexadecane, 45.3% phenyloctane, 17.3% cyclohexyloctane, and 2.3% 2-methylhexadecane) was chosen to reflect the molecular distribution of n-paraffins, i-paraffins, naphthenes, and aromatics in a standard FCC gas oil feed. Analysis of the cracking results of the hydrocarbon mixture determines relative kinetic reaction rates which are decoupled from deactivation, volume expansion, and some adsorption terms. Each zeolite type cracks the hydrocarbons in the mixture at different relative rates, which reflects differences in competitive adsorption, relative diffusion rates, and acid site strength. The relative reaction rates of the hydrocarbon classes over a given zeolite are a strong determinant of the molecular distribution of the gasoline produced by that zeolite catalyst for both the pseudocomponent mixture and the full gas oil. 24 refs., 2 figs., 6 tabs.

  10. Stabilization of heavy metals on spent fluid catalytic cracking catalyst using marine clay.

    PubMed

    Sun, D D; Tay, J H; Qian, C E; Lai, D

    2001-01-01

    Spent fluid catalytic cracking catalyst is a hazardous solid waste generated by petroleum refineries containing vanadium and nickel. The marine clay was used as a matrix to stabilize vanadium and nickel and produce bricks which were then fired at various temperatures. TCLP leaching tests indicated that stabilizing brick had low metal leaching, with a maximum of 6.4 mg/l for vanadium and 19.8 microg/l for nickel. Compressive strength of stabilizing brick was found to range between 20 N/mm2 and 47 N/mm2. It is believed that stabilization and encapsulation mechanisms are responsible for the stabilization of vanadium and nickel. Encapsulation is a process whereby the marine clay matrix forms a physical barrier around the heavy metals which are thus prevented from leaching out into the environment. Incorporation involves the formation of bonds between the marine clay matrix and the heavy metals which thus become incorporated in the clay microstructure. PMID:11794668

  11. Economics for iso-olefin production using the fluid catalytic cracking unit

    SciTech Connect

    McClung, R.G.; Witoshkin, A.; Bogert, D.C.; Winkler, W.S.

    1993-12-31

    The Clean Air Act of 1990 requires use of oxygenates in some gasolines to improve both CO and hydrocarbon auto tailpipe emissions. Various oxygenates are currently being used by the refining industry. For the fully integrated refinery having a fluid catalytic cracking unit, the most commonly used oxygenates are methyl tertiary butyl ether (MTBE) and tertiary amyl ether (TAME). The FCC unit produces the isobutylene and iso-amylases need for manufacture of both MTBE and TAME. The economics for an assumed refinery processing scheme for several FCC cases are examined giving estimates of income and investments for each case. Up to one-third of the total gasoline pool can be made in reformulated gasoline using TAME and MTBE with the FCC unit as the sole source of feedstock. This processing route is much more economical than the alternative scheme using butane isomerization/iosbutane dehydrogenation.

  12. Acidity studies of fluid catalytic cracking catalysts by microcalorimetry and infrared spectroscopy

    SciTech Connect

    Chen, D.; Sharma, S.; Dumesic, J.A. ); Martinez, N. Cardona; Bell, V.A.; Hodge, G.D.; Madon, R.J. )

    1992-08-01

    The acidic properties of a USY-based fluid catalytic cracking catalyst steamed at various severities and amorphous silica-alumina were investigated by microcalorimetry and infrared spectroscopy using pyridine adsorption at 473 K. Microcalorimetric measurements of the differential heat of pyridine adsorption versus adsorbate coverage revealed a heterogeneous acid site distribution for the catalysts. Besides showing the expected progressive decrease in the number of acid sites for pyridine adsorption, measurements showed that the strength of Broensted acid sites decreased with increasing severity of steam treatment. Infrared spectra of adsorbed pyridine revealed a significant decrease in the ratio of Broensted to Lewis acid sites upon steaming. Amorphous silica-alumina had a relatively large number of acid sites of which a large proportion were Broensted acid sites. However, the strength of these Broensted sites was lower than that of the mildly steamed USY catalysts. This lower Broensted acid strength, the authors believe, is related to lower activity for gas-oil cracking over silica-alumina.

  13. Catalytic cracking process

    DOEpatents

    Lokhandwala, Kaaeid A.; Baker, Richard W.

    2001-01-01

    Processes and apparatus for providing improved catalytic cracking, specifically improved recovery of olefins, LPG or hydrogen from catalytic crackers. The improvement is achieved by passing part of the wet gas stream across membranes selective in favor of light hydrocarbons over hydrogen.

  14. High-resolution single-molecule fluorescence imaging of zeolite aggregates within real-life fluid catalytic cracking particles.

    PubMed

    Ristanović, Zoran; Kerssens, Marleen M; Kubarev, Alexey V; Hendriks, Frank C; Dedecker, Peter; Hofkens, Johan; Roeffaers, Maarten B J; Weckhuysen, Bert M

    2015-02-01

    Fluid catalytic cracking (FCC) is a major process in oil refineries to produce gasoline and base chemicals from crude oil fractions. The spatial distribution and acidity of zeolite aggregates embedded within the 50-150 μm-sized FCC spheres heavily influence their catalytic performance. Single-molecule fluorescence-based imaging methods, namely nanometer accuracy by stochastic chemical reactions (NASCA) and super-resolution optical fluctuation imaging (SOFI) were used to study the catalytic activity of sub-micrometer zeolite ZSM-5 domains within real-life FCC catalyst particles. The formation of fluorescent product molecules taking place at Brønsted acid sites was monitored with single turnover sensitivity and high spatiotemporal resolution, providing detailed insight in dispersion and catalytic activity of zeolite ZSM-5 aggregates. The results point towards substantial differences in turnover frequencies between the zeolite aggregates, revealing significant intraparticle heterogeneities in Brønsted reactivity. PMID:25504139

  15. Catalytic cracking process

    SciTech Connect

    Gladrow, E.M.; Winter, W.E.

    1980-04-29

    The octane number of a cracked naphtha can be significantly improved in a catalytic cracking unit, without significant decrease in naphtha yield, by maintaining certain critical concentrations of metals on the catalyst, suitably by blending or adding a heavy metals-containing component to the gas oil feed. Suitably, in a catalytic cracking process unit wherein a gas oil feed is cracked in a cracking reactor (Zone) at an elevated temperature in the presence of a cracking catalyst, the cracking catalyst is regenerated in a regenerator (Regeneration zone) by burning coke off the catalyst, and catalyst is circulated between the reactor and regenerator, sufficient of a metals-containing heavy feedstock is admixed, intermittantly or continuously, with the gas oil feed to deposit metals on said catalyst and raise the metals-content of said catalyst to a level of from about 1500 to about 6000 parts per million, preferably from about 2500 to about 4000 parts per million expressed as equivalent nickel, base the weight of the catalyst, and said metals level is maintained on the catalyst throughout the operation by withdrawing high metals-containing catalyst and adding low metals-containing catalyst to the regenerator.

  16. Fluid catalytic cracking: recent developments on the grand old lady of zeolite catalysis.

    PubMed

    Vogt, E T C; Weckhuysen, B M

    2015-10-21

    Fluid catalytic cracking (FCC) is one of the major conversion technologies in the oil refinery industry. FCC currently produces the majority of the world's gasoline, as well as an important fraction of propylene for the polymer industry. In this critical review, we give an overview of the latest trends in this field of research. These trends include ways to make it possible to process either very heavy or very light crude oil fractions as well as to co-process biomass-based oxygenates with regular crude oil fractions, and convert these more complex feedstocks in an increasing amount of propylene and diesel-range fuels. After providing some general background of the FCC process, including a short history as well as details on the process, reactor design, chemical reactions involved and catalyst material, we will discuss several trends in FCC catalysis research by focusing on ways to improve the zeolite structure stability, propylene selectivity and the overall catalyst accessibility by (a) the addition of rare earth elements and phosphorus, (b) constructing hierarchical pores systems and (c) the introduction of new zeolite structures. In addition, we present an overview of the state-of-the-art micro-spectroscopy methods for characterizing FCC catalysts at the single particle level. These new characterization tools are able to explain the influence of the harsh FCC processing conditions (e.g. steam) and the presence of various metal poisons (e.g. V, Fe and Ni) in the crude oil feedstocks on the 3-D structure and accessibility of FCC catalyst materials. PMID:26382875

  17. Fluid catalytic cracking: recent developments on the grand old lady of zeolite catalysis

    PubMed Central

    2015-01-01

    Fluid catalytic cracking (FCC) is one of the major conversion technologies in the oil refinery industry. FCC currently produces the majority of the world's gasoline, as well as an important fraction of propylene for the polymer industry. In this critical review, we give an overview of the latest trends in this field of research. These trends include ways to make it possible to process either very heavy or very light crude oil fractions as well as to co-process biomass-based oxygenates with regular crude oil fractions, and convert these more complex feedstocks in an increasing amount of propylene and diesel-range fuels. After providing some general background of the FCC process, including a short history as well as details on the process, reactor design, chemical reactions involved and catalyst material, we will discuss several trends in FCC catalysis research by focusing on ways to improve the zeolite structure stability, propylene selectivity and the overall catalyst accessibility by (a) the addition of rare earth elements and phosphorus, (b) constructing hierarchical pores systems and (c) the introduction of new zeolite structures. In addition, we present an overview of the state-of-the-art micro-spectroscopy methods for characterizing FCC catalysts at the single particle level. These new characterization tools are able to explain the influence of the harsh FCC processing conditions (e.g. steam) and the presence of various metal poisons (e.g. V, Fe and Ni) in the crude oil feedstocks on the 3-D structure and accessibility of FCC catalyst materials. PMID:26382875

  18. Gasoline range ether synthesis from light naphtha products of fluid catalytic cracking of Fischer-Tropsch wax

    SciTech Connect

    Reagan, W.J.

    1994-12-31

    The Fluid Catalytic Cracking of Fischer-Tropsch wax (C{sub 20}{sup +} paraffins) produces two to four time the concentration of reactive iso-olefins (isobutylene, isoamylenes, isohexenes) than observed from conventional gas oil feedstocks. Methanol reacts with these olefins to form the corresponding tertiary alkyl ethyl ethers: MTBE, TAME and MTHE`s. These etherification reactions are mildly exothermic and equilibrium limited. The reaction temperature and the olefin molecular structure are important variables for maximum ether yields. The base naphtha research octane number increases by 2-4 numbers after the etherification reaction. The presence of hydrogen has a detrimental affect on ether yields because of hydrogenation of reactive olefins to paraffins. The catalytic cracking of Fischer-Tropsch wax provides a non-conventional source of olefins for ether synthesis that can supplement existing and dwindling petroleum supplies.

  19. Spent fluid catalytic cracking catalyst (FCC) applications in the preparation of hydraulic binders: Pozzolanic properties study

    NASA Astrophysics Data System (ADS)

    Velazquez Rodriguez, Sergio

    At the present work the replacement of Portland cement in pastes and mortars by spent fluid catalytic cracking catalyst (FCC) is studied. The study has been focused in four physicochemical characterization, hydrated lime/catalyst and cement/catalyst pastes and mortars studies, and environmental impact aspects. The FCC characterization establishes that it is a silicoaluminate, having a mainly amorphous structure, with a great specific surface, and that is necessary its mechanical activation (grinding) to obtain a pozzolanic behaviour material. The reactivity was studied by: thermogravimetry, X ray diffractometry, aqueous media electrical conductivity measurements, Fourier transform infrared spectroscopy, scanning electron microscopy, mechanical strength development evaluation and cementing effectiveness k-factor evaluation. The very high pozzolanic activity of the material has been demonstrated, besides that this reactivity has been superior to others similar products such as the metakaolin. The products formed in the hydration, pozzolanic and hydration catalysis of cement reactions have been studied, comparing the reactivity characteristics with others better known pozzolans. The nature of the reaction products between FCC and hydrated lime is similar to the ones formed by the metakaolin, being fundamentally calcium silicate hydrates and hydrated gehlenite, and their formation allow to obtain microstructures with higher mechanical strength. The possibility of preparation materials containing cement/FCC with improved mechanical strength and drying shrinkage has been demonstrated, compared to homologous materials without ground FCC. The optimal FCC dosage for the lime fixation maximization has been determined, showing a pozzolanic behaviour similar to metakaolin, nevertheless very superior to others studied pozzolans, behaviour that is improved with the aid of certain chemical activators, and with the increasing of the curing temperature. Measurements of electrical

  20. X-ray Fluorescence Tomography of Aged Fluid-Catalytic-Cracking Catalyst Particles Reveals Insight into Metal Deposition Processes

    PubMed Central

    Kalirai, Sam; Boesenberg, Ulrike; Falkenberg, Gerald; Meirer, Florian; Weckhuysen, Bert M

    2015-01-01

    Microprobe X-ray fluorescence tomography was used to investigate metal poison deposition in individual, intact and industrially deactivated fluid catalytic cracking (FCC) particles at two differing catalytic life-stages. 3 D multi-element imaging, at submicron resolution was achieved by using a large-array Maia fluorescence detector. Our results show that Fe, Ni and Ca have significant concentration at the exterior of the FCC catalyst particle and are highly co-localized. As concentrations increase as a function of catalytic life-stage, the deposition profiles of Fe, Ni, and Ca do not change significantly. V has been shown to penetrate deeper into the particle with increasing catalytic age. Although it has been previously suggested that V is responsible for damaging the zeolite components of FCC particles, no spatial correlation was found for V and La, which was used as a marker for the embedded zeolite domains. This suggests that although V is known to be detrimental to zeolites in FCC particles, a preferential interaction does not exist between the two. PMID:26613011

  1. Improved high efficiency third stage separator cyclones for separation of fines from fluid catalytic cracking flue gas

    SciTech Connect

    Chitnis, G.K.; Schatz, K.W.; Bussey, B.K.

    1996-12-31

    Stairmand type small diameter (0.254 m) multicyclones were cold flow tested for fluid catalytic cracking third stage separator application. The gas discharge from the cyclone dust outlet into the common collection hopper was found to far exceed the hopper bleed rate (underflow). The excess gas reentrained dust from the hopper back into cyclones, which lowered collection efficiencies. Vortex {open_quotes}stabilization{close_quotes} using apex cones was unsuccessful whereas a Mobil proprietary cyclone modification was successful in minimizing excess gas discharge and dust reentrainment at the cyclone-hopper boundary. In tests at 700 {degrees}C, the modified cyclones captured all particles above 4 {mu}m. Mobil-Kellogg incorporated the modified cyclones in a new third stage separator design which is targeted for achieving lowest opacity and <50 mg/Nm{sup 3} emissions at the stack. The first such unit will be commercialized in Mobil`s newest catalytic cracker (M.W. Kellogg design) under construction in Altona, Australia in late 1996. 5 refs., 4 figs., 2 tabs.

  2. Determination of the pozzolanic activity of fluid catalytic cracking residue. Thermogravimetric analysis studies on FC3R-lime pastes

    SciTech Connect

    Paya, J.; Monzo, J.; Borrachero, M.V.; Velazquez, S.; Bonilla, M

    2003-07-01

    Spent fluid catalytic cracking catalyst (FC3R) from a petrol refinery played a pozzolanic role in portland cement system as revealed by previous experimental data. In the present study, the pozzolanic activity of FC3R was investigated by means thermogravimetry (TG) of cured lime-FC3R pastes. The influence of pozzolan/lime ratio on the pozzolanic activity was investigated. Due to the chemical composition of FC3R is similar to metakaolin (MK), and knowing that MK has a high pozzolanic activity, the latter was used as a material of comparison in this study. The scope of the study is the determination of the pozzolanic activity of FC3R and the evaluation of amount and nature of pozzolanic products. The products obtained from the reaction between FC3R components (SiO{sub 2}/Al{sub 2}O{sub 3}) and calcium hydroxide (CH) have been characterized, finding that the main pozzolanic reaction product was similar to hydrated gehlenite (calcium aluminosilicate hydrate) CSH and CAH were also formed in the reaction. FC3R showed higher pozzolanic reactivity than metakaolin, for low-lime content pastes and early curing age. Thermogravimetry, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) became very useful techniques for evaluation of reactivity.

  3. [Determination of sulfur compounds in fluid catalytic cracking gasoline by gas chromatography with a sulfur chemiluminescence detector].

    PubMed

    Yang, Yongtan; Wang, Zheng; Zong, Baoning; Yang, Haiying

    2004-05-01

    A method for the separation and determination of sulfur compounds in fluid catalytic cracking gasoline (FCC gasoline) by gas chromatography with a sulfur chemiluminescence detector (GC-SCD) was established. Fifty eight sulfur compounds including mercaptan, sulfide, disulfide, thiophene, alkyl thiophenes, benzothiophene and alkyl benzothiophenes were identified based on their retention indexes and the data obtained from gas chromatography with an atomic emission detector (GC-AED). The effects of flow rate of carrier gas and oven temperature were discussed. Detection reproducibilities of main sulfur compounds (thiophene, n-butyl mercaptan, 2-methylthiophene, 3-methylthiophene, 2,4-dimethylthiophene) in FCC gasoline were satisfactory (RSDs were no more than 5.0%) and detection limit for sulfur was 0.1 mg/L. Using thiophene and benzothiophene as testing samples, it was determined that response factor was independent of the molecular structure of sulfur compounds. The linear range was 0.5-800.0 mg/L sulfur with a correlation coefficient of 0.999. PMID:15712900

  4. Multiphase flow modelling using non orthogonal collocated finite volumes : application to fluid catalytical cracking and large scale geophysical flows.

    NASA Astrophysics Data System (ADS)

    Martin, R. M.; Nicolas, A. N.

    2003-04-01

    A modeling approach of gas solid flow, taking into account different physical phenomena such as gas turbulence and inter-particle interactions is presented. Moment transport equations are derived for the second order fluctuating velocity tensor which allow to involve practical closures based on single phase turbulence modeling on one hand and kinetic theory of granular media on the other hand. The model is applied to fluid catalytic cracking processes and explosive volcanism. In the industry as well as in the geophysical community, multiphase flows are modeled using a finite volume approach and a multicorrector algorithm in time in order to determine implicitly the pressures, velocities and volume fractions for each phase. Pressures, and velocities are generally determined at mid-half mesh step from each other following the staggered grid approach. This ensures stability and prevents oscillations in pressure. It allows to treat almost all the Reynolds number ranges for all speeds and viscosities. The disadvantages appear when we want to treat more complex geometries or if a generalized curvilinear formulation of the conservation equations is considered. Too many interpolations have to be done and accuracy is then lost. In order to overcome these problems, we use here a similar algorithm in time and a Rhie and Chow interpolation (1983) of the collocated variables and essentially the velocities at the interface. The Rhie and Chow interpolation of the velocities at the finite volume interfaces allows to have no oscillations of the pressure without checkerboard effects and to stabilize all the algorithm. In a first predictor step, fluxes at the interfaces of the finite volumes are then computed using 2nd and 3rd order shock capturing schemes of MUSCL/TVD or Van Leer type, and the orthogonal stress components are treated implicitly while cross viscous/diffusion terms are treated explicitly. Pentadiagonal linear systems are solved in each geometrical direction (the so

  5. A novel "wastes-treat-wastes" technology: role and potential of spent fluid catalytic cracking catalyst assisted ozonation of petrochemical wastewater.

    PubMed

    Chen, Chunmao; Yu, Ji; Yoza, Brandon A; Li, Qing X; Wang, Gang

    2015-04-01

    Catalytic ozonation is a promising wastewater treatment technology. However, the high cost of the catalyst hinders its application. A novel "wastes-treat-wastes" technology was developed to reuse spent fluid catalytic cracking catalysts (sFCCc) for the ozonation of petrochemical wastewater in this study. Multivalent vanadium (V(4+) and V(5+)), iron (Fe(2+) and Fe(3+)) and nickel (Ni(2+)) oxides that are distributed on the surface of sFCCc and poisoned FCC catalysts are the catalytic components for ozonation. The sFCCc assisted catalytic ozonation (sFCCc-O) of nitrobenzene indicated that the sFCCc significantly promoted hydroxyl radical mediated oxidation. The degradation rate constant of nitrobenzene in sFCCc-O (0.0794 min(-1) at 298 K) was approximately doubled in comparison with that in single ozonation (0.0362 min(-1) at 298 K). The sFCCc-O of petrochemical wastewater increased chemical oxygen demand removal efficiency by three-fold relative to single ozonation. The number of oxygen-containing (Ox) polar contaminants in the effluent (253) from sFCCc-O treatment decreased to about 70% of the initial wastewater (353). The increased oxygen/carbon atomic ratio and decreased number of Ox polar contaminants indicated a high degree of degradation. The present study showed the role and potential of sFCCc for catalytic ozonation of petrochemical wastewater, particularly in an advantage of the cost-effectiveness through "wastes-treat-wastes". PMID:25617869

  6. Deep catalytic cracking, maximize olefin production

    SciTech Connect

    Chapin, L.; Letzsch, W. )

    1994-01-01

    Recent environmental regulations coupled with lead phase out have shifted the focus of the FCC from that of an octane barrel machine to that of a light olefins generator. The light olefins are the necessary feedstock for premium reformulated gasoline (RFG) blending components such as MTBE, TAME and alkylate. The demand for these light olefins will impact the operation of the FCC and Steam Cracker (SC). There will be a need for economical olefin generating processing alternatives to supplement SC's for C[sub 3]= and FCC's for C[sub 3]= through C[sub 5]= RFG component feedstocks. To this end, Stone Webster has recently entered into an agreement with the Research Institute of Petroleum Processing (RIPP) and Sinopec International, both located in the People's Republic of China, to exclusively license RIPP's Deep Catalytic Cracking (DCC) technology outside of China. DCC is a newly developed catalytic cracking process for producing light olefins (C[sub 3]--C[sub 5]) from heavy feedstocks. DCC is a fluidized bed process for selectively cracking a variety of hydrocarbon feedstocks to light olefins. Unlike s steam cracker, the predominate products are propylenes and butylenes, the direct result of catalytic cracking rather than free radical thermal reactions. There are two distinct modes of DCC operation: maximum propylene (Type 1) and maximum iso-olefin production (Type 2). Each mode of operation employs a unique catalyst as well as reaction conditions.

  7. Process for catalytic cracking of hydrocarbons

    SciTech Connect

    Goelzer, A.R.

    1991-04-23

    This patent describes improvement in a fluidized catalytic cracking-regeneration process for cracking hydrocarbon feedstocks or the vapors. The improvement consists of: cracking a first hydrocarbon feed comprising gas oil, residual oil boiling range material or mixtures thereof in a first elongated riser reactor in the presence of regenerated cracking catalyst supplied from the second catalyst regeneration zone at a temperature of at least 1300{degrees}F., cracking a second hydrocarbon feed comprising virgin naphtha, intermediate and heavy cracked naphtha boiling range material or mixtures thereof, having a boiling point to about 450{degrees}F., in a second elongated riser reactor in the presence of regenerated cracking catalyst supplied from the second catalyst regeneration zone at a temperature of at least 1300{degrees}F., combining the vaporous conversion products from the first and second elongated riser reactors in a common disengaging zone therein separating entrained catalyst particles from vaporous product material and passing the combined conversion products to a fractional distillation zone to recover at least a gasoline boiling range material fraction and lighter gaseous hydrocarbon material fraction, a light cycle oil boiling range material fraction and a heavy naphtha boiling range material fraction including slurry oil and higher boiling material fractions.

  8. Life and death of a single catalytic cracking particle.

    PubMed

    Meirer, Florian; Kalirai, Sam; Morris, Darius; Soparawalla, Santosh; Liu, Yijin; Mesu, Gerbrand; Andrews, Joy C; Weckhuysen, Bert M

    2015-04-01

    Fluid catalytic cracking (FCC) particles account for 40 to 45% of worldwide gasoline production. The hierarchical complex particle pore structure allows access of long-chain feedstock molecules into active catalyst domains where they are cracked into smaller, more valuable hydrocarbon products (for example, gasoline). In this process, metal deposition and intrusion is a major cause for irreversible catalyst deactivation and shifts in product distribution. We used x-ray nanotomography of industrial FCC particles at differing degrees of deactivation to quantify changes in single-particle macroporosity and pore connectivity, correlated to iron and nickel deposition. Our study reveals that these metals are incorporated almost exclusively in near-surface regions, severely limiting macropore accessibility as metal concentrations increase. Because macropore channels are "highways" of the pore network, blocking them prevents feedstock molecules from reaching the catalytically active domains. Consequently, metal deposition reduces conversion with time on stream because the internal pore volume, although itself unobstructed, becomes largely inaccessible. PMID:26601160

  9. Catalytic cracking of heavy coker gas oil

    SciTech Connect

    Rustamov, M.I.; Farkhadova, G.T.; Farzullaev, T.S.; Guseinova, S.B.

    1985-07-01

    The authors present results obtained in experiments on the catalytic cracking of heavy coker gas oil on a zeolitic catalyst, using as the catcracker feed either the original coker gas oil or this gas oil after dearomatization by furfural extraction. They conclude from an examination of their data that with the dearomatized feed the yield of butanebutylene cut is 20% higher, the yield of dry gas is lower by a factor of 1.6, and the yield of coke by a factor of 1.2. The characteristics of the naptha obtained by cracking original and dearomatized feeds indicate that the naptha obtained from cracking original gasoil contains 36% aromatics by weight, 10% more than that derived from the dearomatized feed.

  10. Catalytic cracking process with vanadium passivation

    SciTech Connect

    Kennedy, J.V.; Jossens, L.W.

    1991-03-26

    This paper discusses a process for the catalytic cracking of metal-containing hydrocarbonaceous feedstock. It comprises contacting the feedstock under cracking conditions with a dual component catalyst composition. The catalyst composition comprises a first component comprising an active cracking catalyst; and a second component, as a separate and distinct entity, the second component comprising the following materials: a calcium and magnesium containing material selected from the group consisting of dolomite, substantially amorphous calcium magnesium silicate, calcium magnesium oxide, calcium magnesium acetate, calcium magnesium carbonate, and calcium magnesium subcarbonate; a magnesium containing material comprising a hydrous magnesium silicate; and a binder selected from the group consisting of kaolin, bentonite, montmorillonite, saponite, hectorite, alumina, silica, titania, zirconia, silica-alumina, and combinations thereof.

  11. Aluminosilicate nanoparticles for catalytic hydrocarbon cracking.

    PubMed

    Liu, Yu; Pinnavaia, Thomas J

    2003-03-01

    Aluminosilicate nanoparticles containing 9.0-20 nm mesopores were prepared through the use of protozeolitic nanoclusters as the inorganic precursor and starch as a porogen. The calcined, porogen-free composition containing 2 mol % aluminum exhibited the porosity, hydrothermal stability, and acidity needed for the cracking of very large hydrocarbons. In fact, the hydrothermal stability of the nanoparticles to pure steam at 800 degrees C, along with the cumene cracking activity, surpassed the analogous performance properties of ultrastable Y zeolite, the main catalyst component of commercial cracking catalysts. The remarkable hydrothermal stability and catalytic reactivity of the new nanoparticles are attributable to a unique combination of two factors, the presence of protozeolitic nanoclusters in the pore walls and the unprecedented pore wall thickness (7-15 nm). In addition, the excellent catalytic longevity of the nanoparticles is most likely facilitated by the small domain size of the nanoparticles that greatly improves access to the acid sites on the pore walls and minimizes the diffusion length of coke precursors out of the pores. PMID:12603109

  12. Life and death of a single catalytic cracking particle

    PubMed Central

    Meirer, Florian; Kalirai, Sam; Morris, Darius; Soparawalla, Santosh; Liu, Yijin; Mesu, Gerbrand; Andrews, Joy C.; Weckhuysen, Bert M.

    2015-01-01

    Fluid catalytic cracking (FCC) particles account for 40 to 45% of worldwide gasoline production. The hierarchical complex particle pore structure allows access of long-chain feedstock molecules into active catalyst domains where they are cracked into smaller, more valuable hydrocarbon products (for example, gasoline). In this process, metal deposition and intrusion is a major cause for irreversible catalyst deactivation and shifts in product distribution. We used x-ray nanotomography of industrial FCC particles at differing degrees of deactivation to quantify changes in single-particle macroporosity and pore connectivity, correlated to iron and nickel deposition. Our study reveals that these metals are incorporated almost exclusively in near-surface regions, severely limiting macropore accessibility as metal concentrations increase. Because macropore channels are “highways” of the pore network, blocking them prevents feedstock molecules from reaching the catalytically active domains. Consequently, metal deposition reduces conversion with time on stream because the internal pore volume, although itself unobstructed, becomes largely inaccessible. PMID:26601160

  13. New Advances In Multiphase Flow Numerical Modelling Using A General Domain Decomposition and Non-orthogonal Collocated Finite Volume Algorithm: Application To Industrial Fluid Catalytical Cracking Process and Large Scale Geophysical Fluids.

    NASA Astrophysics Data System (ADS)

    Martin, R.; Gonzalez Ortiz, A.

    momentum exchange forces and the interphase heat exchanges are 1 treated implicitly to ensure stability. In order to reduce one more time the computa- tional cost, a decomposition of the global domain in N subdomains is introduced and all the previous algorithms applied to one block is performed in each block. At the in- terface between subdomains, an overlapping procedure is used. Another advantage is that different sets of equations can be solved in each block like fluid/structure interac- tions for instance. We show here the hydrodynamics of a two-phase flow in a vertical conduct as in industrial plants of fluid catalytical cracking processes with a complex geometry. With an initial Richardson number of 0.16 slightly higher than the critical Richardson number of 0.1, particles and water vapor are injected at the bottom of the riser. Countercurrents appear near the walls and gravity effects begin to dominate in- ducing an increase of particulate volumic fractions near the walls. We show here the hydrodynamics for 13s. 2

  14. Biofuel production from catalytic cracking of woody oils.

    PubMed

    Xu, Junming; Jiang, Jianchun; Chen, Jie; Sun, Yunjuan

    2010-07-01

    The catalytic cracking reactions of several kinds of woody oils have been studied. The products were analyzed by GC-MS and FTIR and show the formation of olefins, paraffins and carboxylic acids. Several kinds of catalysts were compared. It was found that the fraction distribution of product was modified by using base catalysts such as CaO. The products from woody oils showed good cold flow properties compared with diesel used in China. The results presented in this work have shown that the catalytic cracking of woody oils generates fuels that have physical and chemical properties comparable to those specified for petroleum based fuels. PMID:20206508

  15. Catalytic cracking catalysts using silicoaluminophosphate molecular sieves

    SciTech Connect

    Pellet, R.J.; Coughlin, P.K.; Staniulis, M.T.; Long, G.N.; Rabo, J.A.

    1987-05-19

    A cracking catalyst is described comprising: a silicoaluminophosphate molecular sieve of U.S. Pat. No. 4,440,871 characterized in its calcined form by an adsorption of isobutane of at least 2 percent by weight at a pressure of 500 torr and a temperature of 20/sup 0/C and having an effective amount of the cations associated with the silicoaluminophosphate molecular sieve selected from the group consisting of H+, ammonium, Group IIA, groups IIIB to VIIB, cerium, lanthanum, praseodymium, neodymium, and promethium.

  16. Hydrogen utilization in fluid catalytic cracking

    SciTech Connect

    Tu, H.

    1982-09-07

    An fcc process in which hydrogen produced by water thermolysis adheres to the catalyst and is used in the reaction zone to achieve improved product selectivity and reduced coke production. The catalyst used is a crystalline aluminosilicate cation exchanged with transitional metal cations. The water thermolysis is carried out in the circulating catalyst upstream of the reaction zone at water thermolysis conditions.

  17. Intensification of catalytic cracking process by addition of heavy catalytic gasoil

    SciTech Connect

    Serikov, P.Yu.; Zaitseva, N.P.; Smidovich, E.V.

    1987-11-01

    The addition of heavy catalytic gasoil to cat cracker feed as a means of reducing the formation of coke was investigated. A vacuum gasoil was used as the feedstock, and a lube oil solvent extract and heavy catalytic gasoil were used as the activating additives. Data showed that feedstocks with the highest kinetic stability had the lowest coke formation in cracking. Kinetic stability was determined by the viscometric method. Test results show that heavy catalytic gasoil has a greater effect on reducing coke yield than the extract used.

  18. Multiple feed point catalytic cracking process using elutriable catalyst mixture

    SciTech Connect

    Herbst, J.A.; Owen, H.; Schipper, P.H.

    1990-05-22

    This patent describes a fluidized catalytic cracking (FCC) process. It comprises: a source of hot, regenerated cracking catalyst having a settling velocity contacts a heavy hydrocarbon feed in a vertical riser reactor adapted to maintain the catalyst and the heavy feed as a dilute phase, the reactor having a cross-sectional area and a base, to produce a mixture of cracked products and spent catalyst, wherein spent catalyst is stripped and charged to a catalyst regeneration zone to produce the hot, regenerated catalyst characterized by use of an elutriable mixture of conventionally sized FCC catalyst and a separate additive catalyst having a higher settling velocity than the conventionally sized FCC catalyst and comprising a shape selective zeolite having a Constraint Index of about 1--12 in a riser having a lower and an upper elutriating section of increased cross-sectional area relative to the riser.

  19. Catalytic process for hydrocarbon cracking using synthetic mesoporous crystalline material

    SciTech Connect

    Le, Q.N.; Thomson, R.T.

    1993-08-03

    A process is described for catalytic cracking of naphtha feedstock which comprises contacting feedstock containing at least 20 wt % C7-C12 alkanes under catalytic reaction conditions with inorganic, porous, non-layered crystalline phase catalyst material exhibiting, after calcination, an X-ray diffraction pattern with at least one peak at a d-spacing greater than 18 Angstrom units and having a benzene adsorption capacity greater than 15 grams of benzene per 100 grams of said material at 50 torr and 25 C, said catalyst material having active Bronsted acid sites; and wherein said cracking conditions include total pressure up to 500 kPa and reaction temperature of 425 to 650 C for less than 50 wt % partial feedstock cracking; thereby producing cracking effluent containing at least 20 wt % isomeric C4-C5 aliphatics including at least 10 wt % C4-C5 tertiary alkene, and at least 10 wt % C4-C5 isoalkane, based on C[sub 5[minus

  20. 40 CFR 63.1565 - What are my requirements for organic HAP emissions from catalytic cracking units?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Pollutants for Petroleum Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Catalytic Cracking Units, Catalytic Reforming Units, Sulfur Recovery Units, and Bypass Lines § 63... limits for organic HAP emissions from catalytic cracking units required in paragraphs (a)(1) and (2)...

  1. 40 CFR 63.1565 - What are my requirements for organic HAP emissions from catalytic cracking units?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Pollutants for Petroleum Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Catalytic Cracking Units, Catalytic Reforming Units, Sulfur Recovery Units, and Bypass Lines § 63... limits for organic HAP emissions from catalytic cracking units required in paragraphs (a)(1) and (2)...

  2. 40 CFR 63.1565 - What are my requirements for organic HAP emissions from catalytic cracking units?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Petroleum Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Catalytic Cracking Units, Catalytic Reforming Units, Sulfur Recovery Units, and Bypass Lines § 63.1565 What... emissions from catalytic cracking units required in paragraphs (a)(1) and (2) of this section do not...

  3. 40 CFR 63.1565 - What are my requirements for organic HAP emissions from catalytic cracking units?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Pollutants for Petroleum Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Catalytic Cracking Units, Catalytic Reforming Units, Sulfur Recovery Units, and Bypass Lines § 63... limits for organic HAP emissions from catalytic cracking units required in paragraphs (a)(1) and (2)...

  4. 40 CFR 63.1565 - What are my requirements for organic HAP emissions from catalytic cracking units?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Petroleum Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Catalytic Cracking Units, Catalytic Reforming Units, Sulfur Recovery Units, and Bypass Lines § 63.1565 What... emissions from catalytic cracking units required in paragraphs (a)(1) and (2) of this section do not...

  5. Severity estimation of cracked shaft vibrations within fluid film bearings

    NASA Astrophysics Data System (ADS)

    Prabhu, B. S.; Sekhar, A. S.

    1995-07-01

    The equations of motion, with four degrees of freedom, taking into consideration the flexibility, damping and cross coupling of the fluid film bearings are derived for a cracked Jeffcott rotor supported on fluid film bearings. Dimensionless equations are developed for dynamic radial load, dynamic pressure developed in the fluid film bearings and coefficient of dissipation considering the journal vibrations in two harmonics; bearing fluid film stiffness and damping coefficients. These are applied to a cracked Jeffcott rotor supported on different types of bearings, i.e., cylindrical journal bearings, offset cylindrical bearings, tilting pad journal bearings and three-lobe bearings. Based on the allowable dynamic pressure developed in the fluid bearings, the severity of cracked shaft and allowable crack depths are estimated in this study. Measurement of dynamic pressure and dissipation for monitoring the crack growth is suggested. However, 2x vibration is the best indicator of cracks in the shafts.

  6. 40 CFR 63.1564 - What are my requirements for metal HAP emissions from catalytic cracking units?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... applies to you. If your catalytic cracking unit is subject to the NSPS for PM in § 60.102 of this chapter, you must meet the emission limitations for NSPS units. If your catalytic cracking unit isn't subject... Table 3 of this subpart. (2) Conduct a performance test for each catalytic cracking unit not subject...

  7. The Investigation of Reducing PAHs Emission from Coal Pyrolysis by Gaseous Catalytic Cracking

    PubMed Central

    Wang, Yulong; Zhao, Ruifang; Zhang, Chun; Li, Guanlong; Zhang, Jing; Li, Fan

    2014-01-01

    The catalytic cracking method of PAHs for the pyrolysis gaseous products is proposed to control their pollution to the environment. In this study, the Py-GC-MS is used to investigate in situ the catalytic effect of CaO and Fe2O3 on the 16 PAHs from Pingshuo coal pyrolysis under different catalytic temperatures and catalyst particle sizes. The results demonstrate that Fe2O3 is effective than that of CaO for catalytic cracking of 16 PAHs and that their catalytic temperature corresponding to the maximum PAHs cracking rates is different. The PAHs cracking rate is up to 60.59% for Fe2O3 at 600°C and is 52.88% at 700°C for CaO. The catalytic temperature and particle size of the catalysts have a significant effect on PAHs cracking rate and CaO will lose the capability of decreasing 16 PAHs when the temperature is higher than 900°C. The possible cracking process of 16 PAHs is deduced by elaborately analyzing the cracking effect of the two catalysts on 16 different species of PAHs. PMID:24963507

  8. Effect of fluid salinity on subcritical crack propagation in calcite

    NASA Astrophysics Data System (ADS)

    Rostom, Fatma; Røyne, Anja; Dysthe, Dag Kristian; Renard, François

    2013-01-01

    The slow propagation of cracks, also called subcritical crack growth, is a mechanism of fracturing responsible for a ductile deformation of rocks under crustal conditions. In the present study, the double-torsion technique was used to measure the effect of fluid chemistry on the slow propagation of cracks in calcite single crystals at room temperature. Time-lapse images and measurements of force and load-point displacement allowed accurate characterization of crack velocities in a range of 10- 8 to 10- 4 m/s. Velocity curves as a function of energy-release rates were obtained for different fluid compositions, varying NH4Cl and NaCl concentrations. Our results show the presence of a threshold in fluid composition, separating two regimes: weakening conditions where the crack propagation is favored, and strengthening conditions where crack propagation slows down. We suggest that electrostatic surface forces that modify the repulsion forces between the two surfaces of the crack may be responsible for this behavior.

  9. Acoustic properties of a crack containing magmatic or hydrothermal fluids

    USGS Publications Warehouse

    Kumagai, H.; Chouet, B.A.

    2000-01-01

    We estimate the acoustic properties of a crack containing maginatic or hydrothermal fluids to quantify the source properties of long-period (LP) events observed in volcanic areas assuming that a crack-like structure is the source of LP events. The tails of synthetic waveforms obtained from a model of a fluid-driven crack are analyzed by the Sompi method to determine the complex frequencies of one of the modes of crack resonance over a wide range of the model parameters ??/a and ??f/??s, where ?? is the P wave velocity of the rock matrix, a is the sound speed of the fluid, and ??f and ??s are the densities of the fluid and rock matrix, respectively. The quality factor due to radiation loss (Qr) for the selected mode almost monotonically increases with increasing ??/a, while the dimensionless frequency (??) of the mode decreases with increasing ??/a and ??f/??s. These results are used to estimate Q and ?? for a crack containing various types of fluids (gas-gas mixtures, liquid-gas mixtures, and dusty and misty gases) for values of a, ??f, and quality factor due to intrinsic losses (Qi) appropriate for these types of fluids, in which Q is given by Q-1 = Qr-1 + Qi-1. For a crack containing such fluids, we obtain Q ranging from almost unity to several hundred, which consistently explains the wide variety of quality factors measured in LP events observed at various volcanoes. We underscore the importance of dusty and misty gases containing small-size particles with radii around 1 ??m to explain long-lasting oscillations with Q significantly larger than 100. Our results may provide a basis for the interpretation of spatial and temporal variations in the observed complex frequencies of LP events in terms of fluid compositions beneath volcanoes. Copyright 2000 by the American Geophysical Union.

  10. Formalization of hydrocarbon conversion scheme of catalytic cracking for mathematical model development

    NASA Astrophysics Data System (ADS)

    Nazarova, G.; Ivashkina, E.; Ivanchina, E.; Kiseleva, S.; Stebeneva, V.

    2015-11-01

    The issue of improving the energy and resource efficiency of advanced petroleum processing can be solved by the development of adequate mathematical model based on physical and chemical regularities of process reactions with a high predictive potential in the advanced petroleum refining. In this work, the development of formalized hydrocarbon conversion scheme of catalytic cracking was performed using thermodynamic parameters of reaction defined by the Density Functional Theory. The list of reaction was compiled according to the results of feedstock structural-group composition definition, which was done by the n-d-m-method, the Hazelvuda method, qualitative composition of feedstock defined by gas chromatography-mass spectrometry and individual composition of catalytic cracking gasoline fraction. Formalized hydrocarbon conversion scheme of catalytic cracking will become the basis for the development of the catalytic cracking kinetic model.

  11. Catalytic cracking of vacuum distillate with additives in fluidized catalyst bed

    SciTech Connect

    Omaraliev, T.O.; Tanashev, S.T.; Kapustin, V.M.

    1987-03-01

    The authors report on a study of the catalytic cracking of straight-run 350-500/sup 0/C vacuum distillates differing substantially in contents of aromatic hydrocarbons and resins, as influenced by the addition of an extract from the No. III lube cut from West Siberian crude. The experiments were performed in a standard catalytic cracking unit in the fluidization mode, using KMTsR zeolitic microbead catalyst.

  12. Role of the pore fluid in crack propagation in glass

    NASA Astrophysics Data System (ADS)

    Mallet, Céline; Fortin, Jérôme; Guéguen, Yves; Bouyer, Fréric

    2015-05-01

    We investigate pore fluid effects due to surface energy variation or due to chemical corrosion in cracked glass. Both effects have been documented through experimental tests on cracked borosilicate glass samples. Creep tests have been performed to investigate the slow crack propagation behavior. We compared the dry case (saturated with argon gas), the nonreactive water saturated case (commercial mineralized water), and the distilled and deionized water saturated case (pure water). Chemical corrosion effects have been observed and evidenced from pH and water composition evolution of the pure water. Then, the comparison of the dry case, the mineral water saturated case, and the corrosion case allow to (i) evidence the mechanical effect of the presence of a pore fluid and (ii) show also the chemical effect of a glass dissolution. Both effects enhance subcritical crack propagation.

  13. FIB-SEM Tomography Probes the Mesoscale Pore Space of an Individual Catalytic Cracking Particle

    PubMed Central

    2016-01-01

    The overall performance of a catalyst particle strongly depends on the ability of mass transport through its pore space. Characterizing the three-dimensional structure of the macro- and mesopore space of a catalyst particle and establishing a correlation with transport efficiency is an essential step toward designing highly effective catalyst particles. In this work, a generally applicable workflow is presented to characterize the transport efficiency of individual catalyst particles. The developed workflow involves a multiscale characterization approach making use of a focused ion beam-scanning electron microscope (FIB-SEM). SEM imaging is performed on cross sections of 10.000 μm2, visualizing a set of catalyst particles, while FIB-SEM tomography visualized the pore space of a large number of 8 μm3 cubes (subvolumes) of individual catalyst particles. Geometrical parameters (porosity, pore connectivity, and heterogeneity) of the material were used to generate large numbers of virtual 3D volumes resembling the sample’s pore space characteristics, while being suitable for computationally demanding transport simulations. The transport ability, defined as the ratio of unhindered flow over hindered flow, is then determined via transport simulations through the virtual volumes. The simulation results are used as input for an upscaling routine based on an analogy with electrical networks, taking into account the spatial heterogeneity of the pore space over greater length scales. This novel approach is demonstrated for two distinct types of industrially manufactured fluid catalytic cracking (FCC) particles with zeolite Y as the active cracking component. Differences in physicochemical and catalytic properties were found to relate to differences in heterogeneities in the spatial porosity distribution. In addition to the characterization of existing FCC particles, our method of correlating pore space with transport efficiency does also allow for an up-front evaluation of

  14. Packed-bed catalytic cracking of oak derived pyrolytic vapors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Catalytic upgrading of pyrolysis vapors derived from oak was carried out using a fixed-bed catalytic column at 425 deg C. The vapors were drawn by splitting a fraction from the full stream of vapors produced at 500 deg C in a 5 kg/hr bench-scale fast pyrolysis reactor system downstream the cyclone s...

  15. Catalytic cracking of bio-oil to organic liquid product (OLP).

    PubMed

    Hew, K L; Tamidi, A M; Yusup, S; Lee, K T; Ahmad, M M

    2010-11-01

    The main objective of this paper is to find the optimum operating condition to upgrade the EFB-derived pyrolysis oil (bio-oil) to liquid fuel, mainly gasoline using Taguchi Method. From the analysis that has been done, it is found that the optimum operating condition for heterogeneous catalytic cracking process is at 400 degrees C, 15min of reaction time using 30g of catalyst weight where operating at this condition produced the highest yield of gasoline fraction which is 91.67 wt.%. This observation proves that EFB-derived pyrolysis oil could be upgraded via heterogeneous catalytic cracking to produce gasoline. PMID:20621470

  16. Asphaltene cracking in catalytic hydrotreating of heavy oil

    SciTech Connect

    Asaoka, S.; Nakata, S.; Shiroto, Y.; Takeuchi, C.

    1981-03-01

    A Boscan crude, an Athabasca bitumen and a Khafji vacuum residue were chosen as typical asphaltenic feedstocks for this study, since they contain a lot of asphaltenes as well as sulfur and their metal contents are considerably different from one another. Any changes on these asphaltenes caused by metals and sulfur removal should, therefore, be observed easier than on other asphaltenes similar to one another. Various measurements reported here vapor pressure osmometry, gel permeation chromatography, nuclear magnetic resonance, x-ray diffraction, small angle x-ray scattering and electron spin resonance are mainly for the asphaltenes isolated from these feedstocks and from their product oils. Further, the model of the asphaltene cracking mechanism is proposed from these results and is discussed in the correspondence with the activities and selectivities among demetallation, desulfurization and asphaltene cracking. The features of asphaltene cracking are summarized as follows: (1) the removal of vanadium and sulfur from asphaltenes; (2) the decrease of molecular weight of remaining asphaltene; (3) the decrease of unit number and no change of unit sheet weight; (4) no change of asphaltene macrostructure in the stacking portion (cracking occurring at the non-stacked portion); (5) no major change of asphaltene particle size; and (6) the change of vanadyl association type in remaining asphaltenes from free to bound state and the decrease of the dissociation energy of the vanadyl. According to these features, the model of asphaltene cracking previously proposed, was confirmed, where the main reactions are the destruction of asphaltene micelles caused by vanadium removal and the depolymerization of asphaltene molecules by removal of heteroatoms such as sulfur. By comparing the model with the reactivities and selectivities, it is shown that the contribution of the two reactions in the model for asphaltene cracking depends on the kinds of feedstocks.

  17. Thermodynamic analysis of a process for producing high-octane gasoline components from catalytic cracking gas

    NASA Astrophysics Data System (ADS)

    Ismailova, Z. R.; Pirieva, Kh. B.; Kasimov, A. A.; Dzhamalova, S. A.; Gadzhizade, S. M.; Nuriev, Sh. A.; Zeinalova, S. Kh.; Dzhafarov, R. P.

    2016-03-01

    The results from a thermodynamic analysis of high-octane gasoline component production from catalytic cracking gases using zeolite catalyst OMNIKAT-210P modified with Ni, Co, Cr are presented. The equilibrium constants of the reactions assumed to occur in this process are calculated, along with the equilibrium yield of the reactions.

  18. 40 CFR Table 1 to Subpart Uuu of... - Metal HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Metal HAP Emission Limits for Catalytic Cracking Units 1 Table 1 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National...

  19. 40 CFR Table 1 to Subpart Uuu of... - Metal HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false Metal HAP Emission Limits for Catalytic Cracking Units 1 Table 1 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED)...

  20. 40 CFR Table 1 to Subpart Uuu of... - Metal HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true Metal HAP Emission Limits for Catalytic Cracking Units 1 Table 1 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED)...

  1. 40 CFR Table 8 to Subpart Uuu of... - Organic HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Organic HAP Emission Limits for Catalytic Cracking Units 8 Table 8 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED)...

  2. 40 CFR Table 8 to Subpart Uuu of... - Organic HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Organic HAP Emission Limits for Catalytic Cracking Units 8 Table 8 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National...

  3. Catalytic cracking. (Latest citations from the NTIS data base). Published Search

    SciTech Connect

    Not Available

    1992-05-01

    The bibliography contains citations concerning applications of catalytic cracking in fluidized beds, moving beds, refineries, vacuum distillation, and reformers. Design criteria, models, controls, and operating procedures are also discussed. (Contains 250 citations and includes a subject term index and title list.)

  4. 40 CFR Table 8 to Subpart Uuu of... - Organic HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... limit for each catalyst regenerator vent . . . 1. Subject to the NSPS for carbon monoxide (CO) in 40 CFR 60.103 CO emissions from the catalyst regenerator vent or CO boiler serving the catalytic cracking... in 40 CFR 60.103 a. CO emissions from the catalyst regenerator vent or CO boiler serving...

  5. Catalytic cracking of a Gippsland reduced crude on zeolite catalysts

    SciTech Connect

    Guerzoni, F.N.; Abbot, J. )

    1994-06-01

    Cracking reactions of a Gippsland reduced crude have been investigated at 520[degrees]C over HY and HZSM-5. Gasolines with similar characteristics can be obtained on both zeolites, although the mechanistic routes to these products are quite distinct. Changes in aromatic product selectivities are consistent with the zeolite pore geometries. Minor quantities of aromatics are formed via hydrogen transfer processes involving product olefins and naphthenes over the faujasite and the cyclization (and to a lesser extent oligomerization) of olefinic species on the pentasil. Dehydrogenation of naphthenic species in the feedstock is also important for aromatic formation. While paraffins are formed via hydrogen transfer processes together with cracking and isomerization of feed paraffins on HY, only the latter route can explain formation of saturated species on HZSM-5. The removal of linear paraffins from the GRC was traced as a function of conversion on HY. It was found that the relative reactivity of the linear paraffins increased monotonically with paraffin chain length. 43 refs., 11 figs., 8 tabs.

  6. Separation of reacted hydrocarbons and catalyst in fluidized catalytic cracking

    SciTech Connect

    Krug, R. R.; Schmidt, P. C.

    1985-02-19

    The present invention relates to a baffle arrangement that improves separation of gaseous hydrocarbon reaction products from catalyst within the reactor vessel of a fluidized catalytic cracker unit. The catalytic reactor vessel includes an outer generally cylindrical shell having a stripping zone arranged at the lower end of the vessel. An inlet riser conduit forming a primary reaction zone extends generally within the shell from the lower end of the vessel to a location near the top of the vessel. A shroud surrounds the upper end of the riser conduit and forms an annular outlet for downwardly discharging a mixture of hydrocarbon and catalyst. According to the present invention, an annular catalyst disengaging riser baffle for deflecting the mixture from the outlet toward the wall of the vessel is arranged on the outside of the riser conduit below the annular outlet and above the stripping zone. Still further, in the preferred embodiment an annular catalyst disengaging wall baffle is arranged on the inside of the shell for again deflecting the mixture, now mostly catalyst, generally downwardly and toward the stripping zone of the vessel. Preferably, the riser baffle and the wall baffle are arranged within the shell such that the baffles in concert with the annular discharge outlet form a partial cyclone separating zone. This cyclone action promotes early disengagement of hydrocarbon vapor from the catalyst and reduces undesirable catalyst carryover in the vapor to conventional cyclones through which the hydrocarbon products are recovered.

  7. Catalytic cracking catalysts for high octane gasoline products

    SciTech Connect

    Chiang, R.L.; Staniulis, M.T.

    1987-07-07

    This patent describes a cracking catalyst comprising a zeolite aluminosilicate having a mole ratio of oxides in the dehydrated state of (0.85-1.1)M/sub 2/n/O:Al/sub 2/O/sub 3:x/SiO/sub 2/ ''M'' is a cation having a valence of ''n;'' ''x'' has a value greater than 6.0 to about 7.0, has an x-ray powder diffraction pattern having at least the d-spacing of Table A; has extraneous silicon atoms in the crystal lattice in the form of framework SiO/sub 4/ tetrahedra; an inorganic oxide matrix; has an effective amount between greater than zero to less than 5 weight percent, based on weight percent, based on the weight of the aluminoscilate employed in the catalyst, expressed as the oxide, of at least one rare earth cation selected from the group consisting of cerium, lanthanum, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium; and less than 1.2 weight percent Na/sub 2/O based on the wright of the aluminosilicate employed in the catalyst.

  8. Selective conversion of bio-oil to light olefins: controlling catalytic cracking for maximum olefins.

    PubMed

    Gong, Feiyan; Yang, Zhi; Hong, Chenggui; Huang, Weiwei; Ning, Shen; Zhang, Zhaoxia; Xu, Yong; Li, Quanxin

    2011-10-01

    Light olefins are the basic building blocks for the petrochemical industry. In this work, selective production of light olefins from catalytic cracking of bio-oil was performed by using the La/HZSM-5 catalyst. With a nearly complete conversion of bio-oil, the maximum yield reached 0.28±0.02 kg olefins/(kg bio-oil), which was close to that from methanol. Addition of La into zeolite efficiently changed the total acid amount of HZSM-5, especially the acid distribution among the strong, medium and weak acid sites. A moderate increase of the number of the medium acid sites effectively enhanced the olefins selectivity and improved the catalyst stability. The comparison between the catalytic cracking and pyrolysis of bio-oil was studied. The mechanism of the conversion of bio-oil to light olefins was also discussed. PMID:21807503

  9. Recent operating experience with Flexicracking commercial developments in short contact time catalytic cracking

    SciTech Connect

    Ladwig, P.K.; Bienstock, M.G.; Citarella, V.A.; Draemel, D.C. )

    1994-01-01

    Short contact time (SCT) catalytic cracking applications have been receiving high attention in recent years, with a large number of revamps of existing FCCU's as well as construction of new facilities. This paper will recap some of these developments and discuss the benefits demonstrated by the application of state-of-the-art riser termination, stripping, and feed injection technologies. Commercial projects demonstrating fast-track project execution, and confirming the outstanding improvements in yields and yield selectivities possible, will also be discussed.

  10. Task 3.9 -- Catalytic tar cracking. Semi-annual report, January 1--June 30, 1995

    SciTech Connect

    Young, B.C.; Timpe, R.C.

    1995-12-31

    Tar produced in the gasification of coal is deleterious to the operation of downstream equipment including fuel cells, gas turbines, hot-gas stream cleanup filters, and pressure swing adsorption systems. Catalytic cracking of tars to smaller hydrocarbons can be an effective means to remove these tars from gas streams and, in the process, generate useful products, e.g., methane gas, which is crucial to the operation of molten carbonate fuel cells. The objectives of this project are to investigate whether gasification tars can be cracked by synthetic nickel-substituted micamontmorillonite, zeolite, or dolomite material; and whether the tars can be cracked selectively by these catalysts to produce a desired liquid and/or gas stream. Results to date are presented in the cited papers.

  11. Analysis of particle-particle interactions in fluidized catalytic cracking units: Effects of collisions, agglomeration, and vaporization

    SciTech Connect

    Kruis, F.E.; Terguer, V.; Lede, J.

    1996-12-31

    A theoretical background is developed for the understanding of the role of particulate interactions in three-phase reactors resulting from turbulent motion, with special application to the Fluid Catalytic Cracking unit. The characteristic times between two collisions in a mixture of catalyst particles and liquid droplets in a gas, the strength of aggregates and efficiency of particle collisions are discussed. A new model has been developed to describe the interaction process between a hot particle, e.g. a catalyst: particle, and a liquid droplet. The vaporization from the droplet surface results in a overpressure in the film around the droplet, thus preventing the droplets and catalysts particles touching each other (similar to the so-called Leidenfrost: phenomenon). A balance of the relevant forces in combination with the heat balance permits the calculation of both the time-dependent distance between the particle and the droplet and the diameter of the evaporating droplet. 10 refs.

  12. Hierarchical Macro-meso-microporous ZSM-5 Zeolite Hollow Fibers With Highly Efficient Catalytic Cracking Capability

    PubMed Central

    Liu, Jia; Jiang, Guiyuan; Liu, Ying; Di, Jiancheng; Wang, Yajun; Zhao, Zhen; Sun, Qianyao; Xu, Chunming; Gao, Jinsen; Duan, Aijun; Liu, Jian; Wei, Yuechang; Zhao, Yong; Jiang, Lei

    2014-01-01

    Zeolite fibers have attracted growing interest for a range of new applications because of their structural particularity while maintaining the intrinsic performances of the building blocks of zeolites. The fabrication of uniform zeolite fibers with tunable hierarchical porosity and further exploration of their catalytic potential are of great importance. Here, we present a versatile and facile method for the fabrication of hierarchical ZSM-5 zeolite fibers with macro-meso-microporosity by coaxial electrospinning. Due to the synergistic integration of the suitable acidity and the hierarchical porosity, high yield of propylene and excellent anti-coking stability were demonstrated on the as-prepared ZSM-5 hollow fibers in the catalytic cracking reaction of iso-butane. This work may also provide good model catalysts with uniform wall thickness and tunable porosity for studying a series of important catalytic reactions. PMID:25450726

  13. Hierarchical macro-meso-microporous ZSM-5 zeolite hollow fibers with highly efficient catalytic cracking capability.

    PubMed

    Liu, Jia; Jiang, Guiyuan; Liu, Ying; Di, Jiancheng; Wang, Yajun; Zhao, Zhen; Sun, Qianyao; Xu, Chunming; Gao, Jinsen; Duan, Aijun; Liu, Jian; Wei, Yuechang; Zhao, Yong; Jiang, Lei

    2014-01-01

    Zeolite fibers have attracted growing interest for a range of new applications because of their structural particularity while maintaining the intrinsic performances of the building blocks of zeolites. The fabrication of uniform zeolite fibers with tunable hierarchical porosity and further exploration of their catalytic potential are of great importance. Here, we present a versatile and facile method for the fabrication of hierarchical ZSM-5 zeolite fibers with macro-meso-microporosity by coaxial electrospinning. Due to the synergistic integration of the suitable acidity and the hierarchical porosity, high yield of propylene and excellent anti-coking stability were demonstrated on the as-prepared ZSM-5 hollow fibers in the catalytic cracking reaction of iso-butane. This work may also provide good model catalysts with uniform wall thickness and tunable porosity for studying a series of important catalytic reactions. PMID:25450726

  14. Catalytic reactor for promoting a chemical reaction on a fluid passing therethrough

    NASA Technical Reports Server (NTRS)

    Roychoudhury, Subir (Inventor); Pfefferle, William C. (Inventor)

    2001-01-01

    A catalytic reactor with an auxiliary heating structure for raising the temperature of a fluid passing therethrough whereby the catalytic reaction is promoted. The invention is a apparatus employing multiple electrical heating elements electrically isolated from one another by insulators that are an integral part of the flow path. The invention provides step heating of a fluid as the fluid passes through the reactor.

  15. Catalytic cracking of the top phase fraction of bio-oil into upgraded liquid oil

    NASA Astrophysics Data System (ADS)

    Sunarno, Rochmadi, Mulyono, Panut; Budiman, Arief

    2016-06-01

    The energy consumption is increasing, while oil reserves as a primary energy resource are decreasing, so that is the reason seeking alternative energy source is inevitable. Biomass especially oil palm empty fruit bunches (EFB) which is abundant in Indonesia can be processed into bio-oil by pyrolysis process. The potential for direct substitution of bio-oil for petroleum may be limited due to the high viscosity, high oxygen content, low heating value, and corrosiveness. Consequently, upgrading of the bio-oil before use is inevitable to give a wider variety of applications of its liquid product. Furthermore, upgrading process to improve the quality of bio-oil by reduction of oxygenates involves process such as catalytic cracking. The objective of this research is to study the effect of operation temperature on yield and composition of upgraded liquid oil and to determine physical properties. Bio-oil derived from EFB was upgraded through catalytic cracking using series tubular reactor under atmospheric pressure on a silica-alumina catalyst. Results show that increasing temperature from 450 to 600 °C, resulting in decreasing of upgraded liquid oil (ULO) yield, decreasing viscosity and density of ULO, but increasing in calorimetric value of ULO. The increasing temperature of cracking also will increase the concentration of gasoline and kerosene in ULO.

  16. Asphaltene cracking in catalytic hydrotreating of heavy oils. 2. study of changes in asphaltene structure during catalytic hydroprocessing

    SciTech Connect

    Sachio, A.; Chisato, T.; Shinichi, N.; Yoshimi, S.

    1983-04-01

    Characteristics in catalytic conversion of asphaltenes in petroleum heavy residues were studied in the hydrotreating process. A Boscan crude, an Athabasca bitumen, and a Khafji vacuum residue were tested as typical feedstocks. Various analyses were made to obtain the properties of asphaltenes before and after the reaction, e.g., changes of heteroatoms such as sulfur and metals, and decreases of molecular weight. The characteristic changes of asphaltene molecules were also investigated by electron spin resonance (ESR) and X-ray analyses. The association and coordination of vanadyl in asphaltenes were studied by the temperature dependence on the ESR spectra, and the sizes of the stacked crystallites and the aggregated asphaltene micelles were measured with X-ray diffraction and small-angle scattering. In the asphaltene cracking mechanism, it was clarified that the main reactions were the destruction of asphaltene micelles caused by vanadium removal and the depolymerization of asphaltene molecules by removal of heteroatoms such as sulfur.

  17. Catalytic and thermal cracking of coal-derived liquid in a fixed-bed reactor

    SciTech Connect

    Shamsi, A.

    1996-04-01

    A coal-derived liquid, obtained from the Coal Technology Corp.`s mild gasification process, was cracked over char produced from Pittsburgh No. 8 coal mixed with Plum Run dolomite in the Foster Wheeler carbonizer. For the purpose of comparison, calcined Plum Run dolomite (PRD), char produced from Pittsburgh No. 8 coal, and silicon carbide (an inert material) were also studied. Coal liquid feed was analyzed by sulfur-selective gas chromatography (GC), liquid chromatography (LC), and proton nuclear magnetic resonance (NMR) and for elemental composition. The gaseous products of cracking were analyzed for hydrocarbons using GC. Most sulfur in the feed was present in molecules heavier than dibenzothiophene and was distributed in a variety of structures. The surviving coal liquid was analyzed by LC. The results indicated that deoxygenation of phenols, dealkylation of aromatic compounds (AR), and condensation of aromatic structures are some of the reactions occurring on the surface of bed materials. Energies of activation for homogeneous and for heterogeneous pyrolysis of the coal liquid were calculated after separating the rate of thermal cracking from the sum of rates of thermal and catalytic cracking.

  18. Energy and environmental research emphasizing low-rank coal: Task 3.9 catalytic tar cracking

    SciTech Connect

    Timpe, R.C.

    1995-09-01

    Tar produced in the gasification of coal is deleterious to the operation of downstream equipment, including fuel cells, gas turbines, hot-gas stream cleanup filters, and pressure-swing absorption systems. Catalytic cracking of tars to smaller hydrocarbons can be an effective means of removing these tars from gas streams and, in the process, generating useful products, such as methane gas, which is crucial to operation of molten carbonate fuel cells. Aerosol tars are not readily removed from gas streams by conventional means and, as a consequence, often end up plugging filters or fouling fuel cells, turbines, or sorbents. Catalytic cracking of these tars to molecular moieties of C{sub 10} or smaller would prevent the problems commonly attributed to the tars. As an example, the moving Bourdon fixed-bed gasifier, by virtue of its efficient countercurrent heat exchange and widespread commercial use, may offer the lowest-cost integrated gasification combined-cycle (IGCC) system if tar generation and wastewater contamination can be minimized. We evaluate the potential of selected catalysts to minimize tar accumulation and maximize char conversion to useful liquid and/or gaseous products. Owing to the potential for production of extremely toxic nickel carbonyl gas, care must be exercised in the use of a NISMM catalyst for cracking tars at high temperatures in reducing atmospheres such as those produced by coal gasification. We observed a fifty percent or more of tar produced during steam gasification of Beulah lignite at temperatures of 400{degrees}-800+{degrees}C when cracked by either dolomite or zeolite maintained at a temperature of 50{degrees}C-100{degrees}C below that of the reactor.

  19. The selective catalytic cracking of Fischer-Tropsch liquids to high value transportation fuels. Final report

    SciTech Connect

    Schwartz, M.M.; Reagon, W.J.; Nicholas, J.J.; Hughes, R.D.

    1994-11-01

    Amoco Oil Company, investigated a selective catalytic cracking process (FCC) to convert the Fischer-Tropsch (F-T) gasoline and wax fractions to high value transportation fuels. The primary tasks of this contract were to (1) optimize the catalyst and process conditions of the FCC process for maximum conversion of F-T wax into reactive olefins for later production of C{sub 4}{minus}C{sub 8} ethers, and (2) use the olefin-containing light naphtha obtained from FCC processing of the F-T wax as feedstock for the synthesis of ethers. The catalytic cracking of F-T wax feedstocks gave high conversions with low activity catalysts and low process severities. HZSM-5 and beta zeolite catalysts gave higher yields of propylene, isobutylene, and isoamylenes but a lower gasoline yield than Y zeolite catalysts. Catalyst selection and process optimization will depend on product valuation. For a given catalyst and process condition, Sasol and LaPorte waxes gave similar conversions and product selectivities. The contaminant iron F-T catalyst fines in the LaPorte wax caused higher coke and hydrogen yields.

  20. Simultaneous realization of high catalytic activity and stability for catalytic cracking of n-heptane on highly exposed (010) crystal planes of nanosheet ZSM-5 zeolite.

    PubMed

    Xiao, Xia; Zhang, Yaoyuan; Jiang, Guiyuan; Liu, Jia; Han, Shanlei; Zhao, Zhen; Wang, Ruipu; Li, Cong; Xu, Chunming; Duan, Aijun; Wang, Yajun; Liu, Jian; Wei, Yuechang

    2016-08-01

    Nanosheet ZSM-5 zeolite with highly exposed (010) crystal planes demonstrates high reactivity and good anti-coking stability for the catalytic cracking of n-heptane, which is attributed to the synergy of high external surface area and acid sites, fully accessible channel intersection acid sites, and hierarchical porosity caused by the unique morphology. PMID:27458616

  1. Catalytic cracking of C5 raffinate to light olefins over phosphorous-modified microporous and mesoporous ZSM-5.

    PubMed

    Lee, Joongwon; Hong, Ung Gi; Hwang, Sunhwan; Youn, Min Hye; Song, In Kyu

    2013-11-01

    Phosphorous-modified microporous and mesoporous ZSM-5 catalysts (XP/C-ZSM5) were prepared with a variation of phosphorous content (X = 0.17, 0.3, 0.7, 1.4, and 2.7 wt%), and they were applied to the production of light olefins (ethylene and propylene) through catalytic cracking of C5 raffinate. The effect of phosphorous content on the physicochemical properties and catalytic activities of XP/C-ZSM5 catalysts was investigated. It was revealed that physicochemical properties of XP/C-ZSM5 catalysts were strongly influenced by phosphorous content. Strong acidity of XP/C-ZSM5 catalysts decreased with increasing phosphorous content. In the catalytic cracking of C5 raffinate, both conversion of C5 raffinate and yield for light olefins (ethylene and propylene) showed volcano-shaped curves with respect to strong acidity. This result indicates that strong acidity of XP/C-ZSM5 catalysts played an important role in determining the catalytic performance in the catalytic cracking of C5 raffinate. Among the catalysts tested, 0.3P/C-ZSM5 catalyst with moderate strong acidity showed the best catalytic performance. PMID:24245282

  2. An Experimental Study of Penny-shaped Fluid-driven Cracks in an Elastic Matrix

    NASA Astrophysics Data System (ADS)

    Stone, Howard

    2015-11-01

    When a pressurized fluid is injected into an elastic matrix, the fluid generates a fracture that grows along a plane and forms a fluid-filled disc-like shape. For example, such problems occur in various natural and industrial applications involving the subsurface of Earth, such as hydraulic fracturing operations. We report a laboratory study of such a fluid-driven crack in a gelatin matrix, study the crack shape as a function of time, and investigate the influence of different experimental parameters such as the injection flow rate, Young's modulus of the matrix, and fluid viscosity. We find that the crack radius increases with time as a power law, which has been predicted both for the limit where viscous effects in the flow along the crack opening control the rate of crack propagation, as well as the limit where fracture toughness controls crack propagation. We vary experimental parameters to probe the physical limits and highlight that for our typical parameters both effects can be significant. Also, we measure the time evolution of crack shape, which has not been studied before. The rescaled crack shapes collapse at longer times, based on an appropriate scaling argument, and again we compare the scaling arguments in different physical limits. The gelatin system provides a useful laboratory model for further studies of fluid-driven cracks, some of which we will mention as they are inspired by the physics of hydraulic fracturing. This work is part of the PhD thesis of Ching-Yao Lai and is a collaboration with Drs. Zhong Zheng and Jason Wexler (Princeton University) and Professor Emilie Dressaire (NYU). Department of Mechanical and Aerospace Engineering.

  3. Observation of crack propagation in saline ice and freshwater ice with fluid inclusion

    NASA Astrophysics Data System (ADS)

    Arakawa, M.; Petrenko, V. F.

    2003-01-01

    A key process of crack propagation in saline ice is the interaction between the crack and fluid inclusions. We observed their interaction in freshwater ice using very high-speed photography (VHSP) and found that the low-density fluids (air and inert liquid, Fluorinert, 1.78 g/cm(3)) could not impede the crack effectively, interrupting the propagation for less than 10 mus. The high-density liquid mercury, (13.8 g/cm(3)) impeded the crack more effectively, stalling the development of the crack for more than 20 mus. The crack velocity in saline ice was measured using two different methods: electrical resistance method (ERM) and VHSP. These two methods returned very different mean velocities, 15 m/s for the ERM and 250 m/s for the VHSP. We found that in ice with conductive liquid inclusions, the ERM measured the time it took to break liquid bridges stretched across a crack rather than the crack velocity. Results from the VHSP show that the maximum crack velocity in saline ice was 500 m/s, which is one-half of that found in freshwater ice. From our results using freshwater ice with inclusions, we conclude that liquid inclusions in saline ice may play a role in this retardation.

  4. Catalytic cracking of palm oil for the production of biofuels: optimization studies.

    PubMed

    Tamunaidu, Pramila; Bhatia, Subhash

    2007-12-01

    Oil palm is widely grown in Malaysia. Palm oil has attracted the attention of researchers to develop an 'environmentally friendly' and high quality fuel, free of nitrogen and sulfur. In the present study, the catalytic cracking of palm oil to biofuel was studied over REY catalyst in a transport riser reactor at atmospheric pressure. The effect of reaction temperature (400-500 degrees C), catalyst/palm oil ratio (5-10) and residence time (10-30s) was studied over the yield of bio-gasoline and gas as fuel. Design of experiments was used to study the effect of operating variables over conversion of palm oil and yield of hydrocarbon fuel. The response surface methodology was used to determine the optimum value of the operating variables for maximum yield of bio-gasoline fraction in the liquid product obtained. PMID:17208441

  5. 40 CFR Table 6 to Subpart Uuu of... - Continuous Compliance With Metal HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true Continuous Compliance With Metal HAP Emission Limits for Catalytic Cracking Units 6 Table 6 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR...

  6. 40 CFR Table 6 to Subpart Uuu of... - Continuous Compliance With Metal HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Continuous Compliance With Metal HAP Emission Limits for Catalytic Cracking Units 6 Table 6 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR...

  7. 40 CFR Table 6 to Subpart Uuu of... - Continuous Compliance With Metal HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false Continuous Compliance With Metal HAP Emission Limits for Catalytic Cracking Units 6 Table 6 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR...

  8. 40 CFR Table 5 to Subpart Uuu of... - Initial Compliance With Metal HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true Initial Compliance With Metal HAP Emission Limits for Catalytic Cracking Units 5 Table 5 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE...

  9. 40 CFR Table 5 to Subpart Uuu of... - Initial Compliance With Metal HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false Initial Compliance With Metal HAP Emission Limits for Catalytic Cracking Units 5 Table 5 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE...

  10. 40 CFR Table 5 to Subpart Uuu of... - Initial Compliance With Metal HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Initial Compliance With Metal HAP Emission Limits for Catalytic Cracking Units 5 Table 5 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE...

  11. 40 CFR Table 13 to Subpart Uuu of... - Continuous Compliance With Organic HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Continuous Compliance With Organic HAP Emission Limits for Catalytic Cracking Units 13 Table 13 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR...

  12. 40 CFR Table 12 to Subpart Uuu of... - Initial Compliance With Organic HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Initial Compliance With Organic HAP Emission Limits for Catalytic Cracking Units 12 Table 12 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR...

  13. 40 CFR Table 9 to Subpart Uuu of... - Operating Limits for Organic HAP Emissions From Catalytic Cracking Units

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Operating Limits for Organic HAP Emissions From Catalytic Cracking Units 9 Table 9 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE...

  14. 40 CFR Table 13 to Subpart Uuu of... - Continuous Compliance With Organic HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... demonstrate continuous compliance by . . . 1. Subject to the NSPS for carbon monoxide (CO) in 40 CFR 60.103 CO emissions from your catalyst regenerator vent or CO boiler serving the catalytic cracking unit must not... ppmv (dry basis). 2. Not subject to the NSPS for CO in 40 CFR 60.103 i. CO emissions from your...

  15. 40 CFR Table 12 to Subpart Uuu of... - Initial Compliance With Organic HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the NSPS for carbon monoxide (CO) in 40 CFR 60.103 CO emissions from your catalyst regenerator vent or CO boiler serving the catalytic cracking unit must not exceed 500 ppmv (dry basis). You have already... initial compliance. 2. Not subject to the NSPS for CO in 40 CFR 60.103 a. CO emissions from your...

  16. 40 CFR Table 10 to Subpart Uuu of... - Continuous Monitoring Systems for Organic HAP Emissions From Catalytic Cracking Units

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Continuous Monitoring Systems for Organic HAP Emissions From Catalytic Cracking Units 10 Table 10 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR...

  17. 40 CFR Table 12 to Subpart Uuu of... - Initial Compliance With Organic HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... . . . 1. Subject to the NSPS for carbon monoxide (CO) in 40 CFR 60.103 CO emissions from your catalyst... demonstrate initial compliance. 2. Not subject to the NSPS for CO in 40 CFR 60.103 a. CO emissions from your catalyst regenerator vent or CO boiler serving the catalytic cracking unit must not exceed 500 ppmv...

  18. 40 CFR Table 13 to Subpart Uuu of... - Continuous Compliance With Organic HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... monoxide (CO) in 40 CFR 60.103 CO emissions from your catalyst regenerator vent or CO boiler serving the... CO concentration at or below 500 ppmv (dry basis). 2. Not subject to the NSPS for CO in 40 CFR 60.103... catalytic cracking unit . . . Subject to this emission limit for your catalyst regenerator vent . . . If...

  19. 40 CFR Table 13 to Subpart Uuu of... - Continuous Compliance With Organic HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... monoxide (CO) in 40 CFR 60.103 CO emissions from your catalyst regenerator vent or CO boiler serving the... CO concentration at or below 500 ppmv (dry basis). 2. Not subject to the NSPS for CO in 40 CFR 60.103... catalytic cracking unit . . . Subject to this emission limit for your catalyst regenerator vent . . . If...

  20. Hydrocarbon Liquid Production via the bioCRACK Process and Catalytic Hydroprocessing of the Product Oil

    DOE PAGESBeta

    Schwaiger, Nikolaus; Elliott, Douglas C.; Ritzberger, Jurgen; Wang, Huamin; Pucher, Peter; Siebenhofer, Matthaus

    2015-02-13

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

  1. Hydrocarbon Liquid Production via the bioCRACK Process and Catalytic Hydroprocessing of the Product Oil

    SciTech Connect

    Schwaiger, Nikolaus; Elliott, Douglas C.; Ritzberger, Jurgen; Wang, Huamin; Pucher, Peter; Siebenhofer, Matthaus

    2015-02-13

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

  2. failure of a fluid catalytic cracker riser line bimetallic weld

    SciTech Connect

    Schult, J.T.

    1983-05-01

    A weld of Inconel 182 to 1 1/4Cr-1/2Mo failed after less than 5000 hours of service in a fluid catalytic cracker riser line. The weld was found to have a unique fracture mode with both fusion line and weld metal separation, but no evidence of base metal rupturing. Poorly documented weld procedures obscured the thermal history, but laboratory simulation and comparision of heat-affected-zone depths inferred that a 600 F preheat was used. It is theorized that high preheat led to amperage reduction, greater first pass base-to-filler metal ratio, poor mixing, and high residual stress in the weld. Stress analysis of the field repair indicated that residual shear stresses would eventually cause creep rupture of the base metal and also demonstrated sensitivity to post-weld heat treatment (PWHT) variables. Of the options of using a second, higher temperature PWHT or a lowered operating temperature, the latter was chosen, and was implemented by removing insulation and adding shielding. This paper reviews the metallurgical aspects of this experience.

  3. Effects of Tip Mass on Stability of Rotating Cantilever Pipe Conveying Fluid with Crack

    NASA Astrophysics Data System (ADS)

    Son, In Soo; Yoon, Han Ik; Lee, Sang Pil; Kim, Dong Jin

    In this paper, the dynamic stability of a rotating cantilever pipe conveying fluid with a crack and tip mass is investigated by numerical method. That is, the effects of the rotating the rotating angular velocity, the mass ratio, the crack and tip mass on the critical flow velocity for flutter instability of system are studied. The equations of motion of rotating pipe are derived by using the extended Hamilton's principle. The crack section of pipe is represented by a local flexibility matrix connecting two undamaged pipe segments. The crack is assumed to be in the first mode of fracture and always opened during the vibrations. Finally, the stability maps of the cracked rotating pipe system as a rotating angular velocity and mass ratio β are presented.

  4. Fluid catalytic cracker catalyst design for nitrogen tolerance

    SciTech Connect

    Young, G.W.

    1986-09-25

    Pulse reaction experiments in which mixtures of 1-4 wt % quinoline or pyridine in hexadecane were reacted over a commercial cracking catalyst (Davison's Super DX) demonstrated the reversible equilibrium process of poison adsorption. The use of a low-activity (for cracking hexadecane) silica-alumina amorphous matrix component, mixed with the Super DX, resulted in a higher conversion of a hexadecane-quinoline mixture compared to Super DX alone. Gas oil cracking studies with various levels of preblended quinoline were performed using catalysts in which both zeolite and active matrix content were varied. The activity and selectivity results can be used to develop design criteria for cracking catalysts that are to be used in the processing of feedstocks containing unusually high organic nitrogen levels. The general applicability of the quinoline studies was verified by similar studies using a naturally occurring high nitrogen content gas oil and blends of it with a shale oil.

  5. Fluid-driven cracks in an elastic matrix in the toughness-dominated limit.

    PubMed

    Lai, Ching-Yao; Zheng, Zhong; Dressaire, Emilie; Stone, Howard A

    2016-10-13

    The dynamics of fluid-driven cracks in an elastic matrix is studied experimentally. We report the crack radius R(t) as a function of time, as well as the crack shapes w(r,t) as a function of space and time. A dimensionless parameter, the pressure ratio Δpf/Δpv, is identified to gauge the relative importance between the toughness (Δpf) and viscous (Δpv) effects. In our previous paper (Lai et al. 2015 Proc. R. Soc. A 471, 20150255. (doi:10.1098/rspa.2015.0255)), we investigated the viscous limit experimentally when the toughness-related stresses are negligible for the crack propagation. In this paper, the experimental parameters, i.e. Young's modulus E of the gelatin, viscosity μ of the fracturing liquid and the injection flow rate Q, were chosen so that the viscous effects in the flow are negligible compared with the toughness effects, i.e. Δpf/Δpv≫1. In this limit, the crack dynamics can be described by the toughness-dominated scaling laws, which give the crack radius R(t)∝t(2/5) and the half maximum crack thickness W(t)∝t(1/5) The experimental results are in good agreement with the predictions of the toughness scaling laws: the experimental data for crack radius R(t) for a wide range of parameters (E,μ,Q) collapse after being rescaled by the toughness scaling laws, and the rescaled crack shapes w(r,t) also collapse to a dimensionless shape, which demonstrates the self-similarity of the crack shape. The appropriate choice of the viscous or toughness scaling laws is important to accurately describe the crack dynamics.This article is part of the themed issue 'Energy and the subsurface'. PMID:27597782

  6. The selective catalytic cracking of Fischer-Tropsch liquids to high value transportation fuels. Report number 13: Quarterly technical progress report for second quarter fiscal year 1992 (January 1--March 31, 1992)

    SciTech Connect

    Reagan, W.J.

    1992-12-31

    Amoco Oil Company is investigating a selective catalytic cracking process to convert the Fischer-Tropsch gasoline and wax fractions to high value transportation fuels. The wax feedstock for this program is a commercial sample of Fischer-Tropsch product from Sasol. The wax feedstock readily converts over conventional fluid catalytic cracking (FCC) catalysts (85%+ conversion) to high yields of C{sub 4}-gas and gasoline. The work in this area focuses on the effects of process variables and catalyst types. Some initial wax cracking tests on the pilot plant unit continue. These test results also show high conversion (85%+) of the wax feedstock to light gases and gasoline. The ranking of the three zeolite catalyst types for C{sub 4}-C{sub 5} iso-olefin production is similar to the findings of the small scale screening test program. The catalytic cracking test results from both the small scale test unit and the pilot plant suggest that very mild process conditions and low activity catalysts are needed to lower the overall wax conversion. The target light olefin yields vary with catalyst type and the process conditions.

  7. Conversion of isoprenoid oil by catalytic cracking and hydrocracking over nanoporous hybrid catalysts.

    PubMed

    Kimura, Toshiyuki; Liu, Chen; Li, Xiaohong; Maekawa, Takaaki; Asaoka, Sachio

    2012-01-01

    In order to produce petroleum alternatives from biomass, a significant amount of research has been focused on oils from microalgae due to their origin, which would not affect food availability. Nanoporous hybrid catalysts composed of ns Al₂O₃ and zeolites have been proven to be very useful compared to traditional catalysts in hydrotreating (HT), hydrocracking (HC), and catalytic cracking (CC) of large molecules. To evaluate the reaction scheme and products from model isoprenoid compounds of microalgae oil, nanoporous hybrid catalyst technologies (CC: ns Al₂O₃/H-USY and ns Al₂O₃/H-GaAlMFI; HC: [Ni-Mo/γ-Al₂O₃]/ns Al₂O₃/H-beta) were studied. The major product from CC on ns Al₂O₃/H-USY was highly aromatic gasoline, while the product from HC was half-isoparaffinic/olefinic kerosene. Although more than 50 wt% of the products from HT/CC on the USY catalyst was liquefied petroleum gas due to overcracking, the product from HT/CC on the MFI catalyst was high-octane-number gasoline. Delightfully, the product from HT/HC was kerosene and its average number was 11, with more than 80 wt% being isoparaffinic. As a result, it was demonstrated that hydrotreating may convert isoprenoid oil from microalgae over nanoporous hybrid catalysts into a variety of products. PMID:22791962

  8. Conversion of Isoprenoid Oil by Catalytic Cracking and Hydrocracking over Nanoporous Hybrid Catalysts

    PubMed Central

    Kimura, Toshiyuki; Liu, Chen; Li, Xiaohong; Maekawa, Takaaki; Asaoka, Sachio

    2012-01-01

    In order to produce petroleum alternatives from biomass, a significant amount of research has been focused on oils from microalgae due to their origin, which would not affect food availability. Nanoporous hybrid catalysts composed of ns Al2O3 and zeolites have been proven to be very useful compared to traditional catalysts in hydrotreating (HT), hydrocracking (HC), and catalytic cracking (CC) of large molecules. To evaluate the reaction scheme and products from model isoprenoid compounds of microalgae oil, nanoporous hybrid catalyst technologies (CC: ns Al2O3/H-USY and ns Al2O3/H-GaAlMFI; HC: [Ni-Mo/γ-Al2O3]/ns Al2O3/H-beta) were studied. The major product from CC on ns Al2O3/H-USY was highly aromatic gasoline, while the product from HC was half-isoparaffinic/olefinic kerosene. Although more than 50 wt% of the products from HT/CC on the USY catalyst was liquefied petroleum gas due to overcracking, the product from HT/CC on the MFI catalyst was high-octane-number gasoline. Delightfully, the product from HT/HC was kerosene and its average number was 11, with more than 80 wt% being isoparaffinic. As a result, it was demonstrated that hydrotreating may convert isoprenoid oil from microalgae over nanoporous hybrid catalysts into a variety of products. PMID:22791962

  9. The effect of fluid composition, salinity, and acidity on subcritical crack growth in calcite crystals

    NASA Astrophysics Data System (ADS)

    Bergsaker, Anne Schad; Røyne, Anja; Ougier-Simonin, Audrey; Aubry, Jérôme; Renard, François

    2016-03-01

    Chemically activated processes of subcritical cracking in calcite control the time-dependent strength of this mineral, which is a major constituent of the Earth's brittle upper crust. Here experimental data on subcritical crack growth are acquired with a double torsion apparatus to characterize the influence of fluid pH (range 5-7.5) and ionic strength and species (Na2SO4, NaCl, MgSO4, and MgCl2) on the propagation of microcracks in calcite single crystals. The effect of different ions on crack healing has also been investigated by decreasing the load on the crack for durations up to 30 min and allowing it to relax and close. All solutions were saturated with CaCO3. The crack velocities reached during the experiments are in the range 10-9-10-2 m/s and cover the range of subcritical to close to dynamic rupture propagation velocities. Results show that for calcite saturated solutions, the energy necessary to fracture calcite is independent of pH. As a consequence, the effects of fluid salinity, measured through its ionic strength, or the variation of water activity have stronger effects on subcritical crack propagation in calcite than pH. Consequently, when considering the geological sequestration of CO2 into carbonate reservoirs, the decrease of pH within the range of 5-7.5 due to CO2 dissolution into water should not significantly alter the rate of fracturing of calcite. Increase in salinity caused by drying may lead to further reduction in cracking and consequently a decrease in brittle creep. The healing of cracks is found to vary with the specific ions present.

  10. The seismic properties of sintered glass-bead media: effects of thermal cracking and fluid saturation

    NASA Astrophysics Data System (ADS)

    Li, Y.; Jackson, I.; David, E.; Schmitt, D. R.

    2013-12-01

    The stiffness of rocks is significantly affected by the presence of cracks as well as pore fluids, the latter potentially increasing the effective stiffness of cracks. Reversible pore-fluid flow within the crack network, occurring during seismic wave propagation, may result in strongly frequency dependent seismic properties. Theoretical models for fluid flow induced seismic wave dispersion have been proposed but have so far not been subject to thorough experimental testing. Soda-lime-silica glass beads, of ~300 μm diameter were sintered near the glass transition temperature to produce a synthetic analogue for sedimentary rock with low porosity (~2%) and a simpler microstructure. Widely distributed cracks with uniformly low aspect ratio (~0.0007) and crack porosity ~0.2% were introduced by quenching heated cylindrical samples into liquid water at room temperature. Combined use of low-frequency (mHz-Hz) forced oscillation techniques at the Australian National University with ultrasonic pulse transmission methods (MHz) at the University of Alberta, is allowing a broadband measurement of seismic velocities and attenuation on a thermally cracked glass-bead sample. A recent upgrade of the data acquisition system on the apparatus for forced oscillation measurements is providing improved precision in determining shear and Young's moduli, measured at seismic frequencies, reveal a strong systematic variation with effective pressure (Peff=Pc-Pf) and some relaxation at longer oscillation periods tentatively attributed to fluid flow. Under water-saturated conditions, at low frequencies, both shear and Young's moduli are noticeably higher than under dry or argon-saturated conditions, possibly attributed to spatial restricted flow of water during forced-oscillation tests. Ongoing measurement of ultrasonic velocities should thus provide the 'intermediate' to 'high' frequency bounds on elastic moduli.

  11. Production of Light Olefins Through Catalytic Cracking of C5 Raffinate Over Surface-Modified ZSM-5 Catalyst.

    PubMed

    Lee, Joongwon; Park, Seungwon; Hong, Ung Gi; Jun, Jin Oh; Song, In Kyu

    2015-10-01

    Surface modification of phosphorous-containing porous ZSM-5 catalyst (P/C-ZSM5-Sil.(X)) was carried out by a chemical liquid deposition (CLD) method using tetraethyl orthosilicate (TEOS) as a silylation agent. Different amount of TEOS (X = 5, 10, 20, and 30 wt%) was introduced into P/C-ZSM5il.(X) catalysts for surface modification. The catalysts were used for the production of light olefins (ethylene and propylene) through catalytic cracking of C5 raffinate. It was found that external surface acidity of P/C-ZSM5-Sil.(X) catalysts significantly decreased with increasing TEOS content. In the catalytic reaction, both conversion of C5 raffinate and yield for light olefins showed volcano-shaped curves with respect to TEOS content. Among the catalysts tested, P/C-ZSM5-Sil.(20) catalyst exhibited the best catalytic performance in terms of conversion of C5 raffinate and yield for light olefins. Thus, an optimal TEOS content was required for CLD treatment to maximize light olefin production in the catalytic cracking of C5 raffinate over P/C-ZSM5-Sil.(X) catalysts. PMID:26726509

  12. Instability in Immiscible Fluids Displacement from Cracks and Porous Samples

    NASA Astrophysics Data System (ADS)

    Smirnov, N. N.; Nikitin, V. F.; Ivashnyov, O. E.

    2002-01-01

    problems of terrestrial engineering and technology. Surface tension affected flows in porous media could be much better understood in microgravity studies eliminating the masking effects of gravity. Saffman-Taylor instability of the interface could bring to formation and growth of "fingers" of gas penetrating the bulk fluid. The growth of fingers and their further coalescence could not be described by the linear analysis. Growth of fingers causes irregularity of the mixing zone. The tangential velocity difference on the interface separating fluids of different densities and viscousities could bring to a Kelvin-Helmholtz instability resulting in "diffusion of fingers" partial regularization of the displacement mixing zone. Thus combination of the two effects would govern the flow in the displacement process. fracture under a pressure differential displacing the high viscosity residual fracturing fluid. There are inherent instability and scalability problems associated with viscous fingering that play a key role in the cleanup procedure. Entrapment of residual fracturing fluid by the gas flow lowers down the quality of a fracture treatment leaving most of fluid in the hydraulic fracture thus decreasing the production rate. The gravity effects could play essential role in vertical hydraulic fractures as the problem is scale dependent. displacement of viscous fluid by a less viscous one in a two-dimensional channel with vertical breaks, and to determine characteristic size of entrapment zones. Extensive direct numerical simulations allow to investigate the sensitivity of the displacement process to variation of values of the main governing parameters. were found for the two limiting cases: infinitely wide cell, and narrow cell with an infinitely small gap between the finger and the side walls. governing parameters. The obtained solutions allowed to explain the physical meaning of the exiting empirical criteria for the beginning of viscous fingering and the growth of a

  13. Crack

    MedlinePlus

    ... sound the drug makes as it heats up. Short-Term Effects Crack is a stimulant that is absorbed through ... quickly, after about 5 or 10 minutes. Other short-term effects include: higher heart rate, breathing rate, blood pressure , ...

  14. Insights into Volcanic Tremor: A Linear Stability Analysis of Waves Propagating Along Fluid-Filled Cracks

    NASA Astrophysics Data System (ADS)

    Lipovsky, B.; Dunham, E. M.

    2012-12-01

    Crack waves are guided waves along fluid-filled cracks that propagate with phase velocity less than the sound wave speed. Chouet (JGR, 1986) and Ferrazzini and Aki (JGR, 1977) have shown that such waves could explain volcanic tremor in terms of the resonant modes of a finite length magma-filled crack. Based on an idealized lumped-parameter model, Julian (JGR, 1994) further proposed that the steady flow of a viscous magma in a volcanic conduit is unstable to perturbations, leading to self-excited oscillations of the conduit walls and radiation of seismic waves. Our objective is to evaluate the possibility of self-excited oscillations within a rigorous, continuum framework. Our specific focus has been on basaltic fissure eruptions. In a typical basaltic fissure system, the magnitudes of the wave restoring forces, fluid compressibility and wall elasticity, are highly depth dependent. Because of the elevated fluid compressibility from gas exsolution at shallow depths, fluid pressure perturbations in this regime propagate as acoustic waves with effectively rigid conduit walls. Below the exsolution depth, the conduit walls are more compliant relative to the magma compressibility and perturbations propagate as dispersive crack waves. Viscous magma flow through such a fissure will evolve to a fully developed state characterized by a parabolic velocity profile in several to tens of seconds. This time scale is greater than harmonic tremor periods, typically 0.1 to 1 second. A rigorous treatment of the wave response to pressure perturbations therefore requires a general analysis of conduit flow that is not in a fully developed state. We present a linearized analysis of the coupled fluid and elastic response to general flow perturbations. We assume that deformation of the wall is linear elastic. As our focus is on wavelengths greatly exceeding the crack width, fluid flow is described by a quasi-one dimensional, or width-averaged, model. We account for conservation of magma

  15. Multidimensional gas chromatography for the characterization of permanent gases and light hydrocarbons in catalytic cracking process.

    PubMed

    Luong, J; Gras, R; Cortes, H J; Shellie, R A

    2013-01-01

    An integrated gas chromatographic system has been successfully developed and implemented for the measurement of oxygen, nitrogen, carbon monoxide, carbon dioxide and light hydrocarbons in one single analysis. These analytes are frequently encountered in critical industrial petrochemical and chemical processes like catalytic cracking of naphtha or diesel fuel to lighter components used in gasoline. The system employs a practical, effective configuration consisting of two three-port planar microfluidic devices in series with each other, having built-in fluidic gates, and a mid-point pressure source. The use of planar microfluidic devices offers intangible advantages like in-oven switching with no mechanical moving parts, an inert sample flow path, and a leak-free operation even with multiple thermal cycles. In this way, necessary features such as selectivity enhancement, column isolation, column back-flushing, and improved system cleanliness were realized. Porous layer open tubular capillary columns were employed for the separation of hydrocarbons followed by flame ionization detection. After separation has occurred, carbon monoxide and carbon dioxide were converted to methane with the use of a nickel-based methanizer for detection with flame ionization. Flow modulated thermal conductivity detection was employed to measure oxygen and nitrogen. Separation of all the target analytes was achieved in one single analysis of less than 12 min. Reproducibility of retention times for all compounds were found to be less than 0.1% (n=20). Reproducibility of area counts at two levels, namely 100 ppm(v) and 1000 ppm(v) over a period of two days were found to be less than 5.5% (n=20). Oxygen and nitrogen were found to be linear over a range from 20 ppm(v) to 10,000 ppm(v) with correlation coefficients of at least 0.998 and detection limits of less than 10 ppm(v). Hydrocarbons of interest were found to be linear over a range from 200 ppb(v) to 1000 ppm(v) with correlation

  16. Catalytic gasification studies in a pressurized fluid-bed unit

    SciTech Connect

    Mudge, L.K.; Baker, E.G.; Mitchell, D.H.; Robertus, R.J.; Brown, M.D.

    1983-07-01

    The purpose of the project is to evaluate the technical and economic feasibility of producing specific gas products via the catalytic gasification of biomass. This report presents the results of research conducted from October 1980 to November 1982. In the laboratory scale studis, active catalysts were developed for generation of synthesis gases from wood by steam gasification. A trimetallic catalyst, Ni-Co-Mo on silica-alumina doped with 2 wt % Na, was found to retain activity indefinitely for generation of a methanol synthesis gas from wood at 1380/sup 0/F (750/sup 0/C) and 1 atm (100 kPa) absolute pressure. Catalysts for generation of a methane-rich gas were deactivated rapidly and could not be regenerated as required for economic application. Sodium carbonate and potassium carbonate were effective as catalysts for conversion of wood to synthesis gases and methane-rich gas and should be economically viable. Catalytic gasification conditions were found to be suitable for processing of alternative feedstocks: bagasse, alfalfa, rice hulls, and almond hulls. The PDU was operated successfully at absolute pressures of up to 10 atm (1000 kPa) and temperatures of up to 1380/sup 0/F (750/sup 0/C). Yields of synthesis gases at elevated pressure were greater than those used for previous economic evaluations. A trimetallic catalyst, Ni-Cu-Mo on silica-alumina, did not display a long life as did the doped trimetallic catalyst used in laboratory studies. A computer program for a Radio Shack TRS-80 Model I microcomputer was developed to evaluate rapidly the economics of producing either methane or methanol from wood. The program is based on economic evaluations reported in previous studies. Improved yields from the PDU studies were found to result in a reduction of about 9 cents/gal in methanol cost.

  17. A new model of reaction-driven cracking: fluid volume consumption and tensile failure during serpentinization

    NASA Astrophysics Data System (ADS)

    Eichenbaum-Pikser, J. M.; Spiegelman, M. W.; Kelemen, P. B.; Wilson, C. R.

    2013-12-01

    Reactive fluid flow plays an important role in a wide range of geodynamic processes, such as melt migration, formation of hydrous minerals on fault surfaces, and chemical weathering. These processes are governed by the complex coupling between fluid transport, reaction, and solid deformation. Reaction-driven cracking is a potentially critical feedback mechanism, by which volume change associated with chemical reaction drives fracture in the surrounding rock. It has been proposed to play a role in both serpentinization and carbonation of peridotite, motivating consideration of its application to mineral carbon sequestration. Previous studies of reactive cracking have focused on the increase in solid volume, and as such, have considered failure in compression. However, if the consumption of fluid is considered in the overall volume budget, the reaction can be net volume reducing, potentially leading to failure in tension. To explore these problems, we have formulated and solved a 2-D model of coupled porous flow, reaction kinetics, and elastic deformation using the finite element model assembler TerraFERMA (Wilson et al, G3 2013 submitted). The model is applied to the serpentinization of peridotite, which can be reasonably approximated as the transfer of a single reactive component (H2O) between fluid and solid phases, making it a simple test case to explore the process. The behavior of the system is controlled by the competition between the rate of volume consumption by the reaction, and the rate of volume replacement by fluid transport, as characterized by a nondimensional parameter χ, which depends on permeability, reaction rate, and the bulk modulus of the solid. Large values of χ correspond to fast fluid transport relative to reaction rate, resulting in a low stress, volume replacing regime. At smaller values of χ, fluid transport cannot keep up with the reaction, resulting in pore fluid under-pressure and tensile solid stresses. For the range of χ relevant

  18. Influence of feedstock quality on operation of 1A/1M commercial catalytic cracking unit

    SciTech Connect

    Pryanikov, E.I.; Abdullaev, M.A.; Aleksanyan, A.P.; Guseinov, A.M.; Mkrtychev, A.A.; Rustamov, I.I.

    1983-03-01

    This article summarizes and correlates the results from the operation of the unit in 2-stage cracking, in which the fresh feed is cracked in the reactor with rising cocurrent flow of catalyst, and the bottom product from the distillation tower (cut distilling above 195/sup 0/C) is cracked in the reactor with rising semicocurrent flow of catalyst. The presence of heavy aromatic hydrocarbons in the feed has a significant effect on the yields of naphtha and stabilizer heat cut. With increasing amounts of the light cuts in the feed, the yield of desired products and the conversion level decreased.

  19. Analysis of the organic liquid produced from catalytic cracking of crude palm oil in the presence of alumina supported catalysts

    NASA Astrophysics Data System (ADS)

    Ramli, Anita; Razak, Rozlina Abdul

    2012-09-01

    Catalytic cracking of crude palm oil (CPO) was studied in the presence of alumina, 1% Pt/Al2O3 and 1% Pd/Al2O3 as catalyst. The CPO to catalyst weight ratio used was 1:0.05. The experiment was carried out in a simple liquid-phase batch reactor at atmospheric pressure where the sample was heated to 300-350 δC. Products formed were organic liquid products (OLP) and gaseous product with the solid residue remains in the reactor. The total conversion of CPO was only between 25 - 31% where the residue is suggested to be mainly of polimerised CPO. The OLP was analysed using a gas chromatography with FID detector. Analyses show that the selectivity to liquid fuel is influence by the catalyst used whereby Al2O3 gives the highest selectivity to gasoline while 1% Pt/Al2O3 has the highest selectivity to diesel. However, 1% Pd/Al2O3 is not a suitable catalyst for catalytic cracking of CPO to liquid fuel where less than 17.5% of OLP produced could be classified as liquid fuel.

  20. The selective catalytic cracking of Fischer-Tropsch liquids to high value transportation fuels. Report number 24: Quarterly technical progress report for fourth quarter fiscal year 1992 (July 1--September 30, 1992)

    SciTech Connect

    Reagan, W.J.

    1992-12-31

    Amoco Oil Company is investigating a selective catalytic cracking process to convert the Fischer-Tropsch gasoline and wax fractions to high value transportation fuels. The wax feedstock for this program, a commercial sample of fischer-Tropsch product from Sasol, is a high melting point, (>220 F), high boiling range (50% boiling above 1,000 F), largely paraffinic material. The wax feedstock readily converts over conventional fluid catalytic cracking (FCC) catalysts (85%+ conversion) to high yields of C{sub 4}-gas and naphtha. Three different types of zeolite catalysts and one amorphous cracking catalyst show wide variations of product yields as a function of wax feedstock conversion. The Beta and HZSM-5 zeolite catalysts have higher target light olefin (isobutylene and isoamylenes) yields than the Y zeolite sample. The HSZM-5 sample also produces the highest yields of propylene. Further work continues on various commercial and experimental HZSM-5 samples. There are some clear wax conversion variations among the samples. However, product selectivity differences are small and difficult to measure accurately. A series of rare earth exchanged Y zeolite catalysts show the expected rare earth effect: increased rare earth exchange gives higher naphtha and lower olefin yields. Several new FCC catalysts with low (10%) zeolite content have been prepared and analyzed. The zeolite Beta sample appears to have a lower hydrothermal stability than zeolite Y catalyst. The catalytic cracking test results from both the small scale test unit and the pilot plant suggest that very mild process conditions and low activity catalysts are needed to lower the overall wax conversion. The target light olefin yields vary with catalyst type and the process conditions.

  1. Inverted fractionation apparatus and use in a heavy oil catalytic cracking process

    SciTech Connect

    Owen, H.

    1991-05-28

    This patent describes a process for fractionating a superheated, cracked vapor stream having a temperature above about 750{degrees} F. and comprising a full boiling range cracked product stream including normally gaseous hydrocarbons, at least normally liquid product streams selected from the group of naphtha boiling range hydrocarbons, light cycle oil boiling range hydrocarbons, heavy cycle oil boiling range hydrocarbons and mixtures thereof into liquid product fractions, the process comprising charging the superheated vapor to a vertical distillation apparatus having a height of at least 20 meters, and comprising an upper desuperheating zone and a lower fraction zone.

  2. Catalytic thermal cracking of post-consumer waste plastics to fuels: Part 1 - Kinetics and optimization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermogravimetric analysis (TGA) was used to investigate thermal and catalytic pyrolysis of waste plastics such as prescription bottles (polypropylene/PP), high density polyethylene, landfill liners (polyethylene/PE), packing materials (polystyrene/PS), and foams (polyurethane/PU) into crude plastic...

  3. 40 CFR Table 8 to Subpart Uuu of... - Organic HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... emission limit for each catalyst regenerator vent . . . 1. Subject to the NSPS for carbon monoxide (CO) in 40 CFR 60.103 CO emissions from the catalyst regenerator vent or CO boiler serving the catalytic... for CO in 40 CFR 60.103 a. CO emissions from the catalyst regenerator vent or CO boiler serving...

  4. 40 CFR Table 8 to Subpart Uuu of... - Organic HAP Emission Limits for Catalytic Cracking Units

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... emission limit for each catalyst regenerator vent . . . 1. Subject to the NSPS for carbon monoxide (CO) in 40 CFR 60.103 CO emissions from the catalyst regenerator vent or CO boiler serving the catalytic... for CO in 40 CFR 60.103 a. CO emissions from the catalyst regenerator vent or CO boiler serving...

  5. 40 CFR Table 11 to Subpart Uuu of... - Requirements for Performance Tests for Organic HAP Emissions From Catalytic Cracking Units Not...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Requirements for Performance Tests for Organic HAP Emissions From Catalytic Cracking Units Not Subject to New Source Performance Standard (NSPS) for Carbon Monoxide (CO) 11 Table 11 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)...

  6. 40 CFR Table 7 to Subpart Uuu of... - Continuous Compliance With Operating Limits for Metal HAP Emissions From Catalytic Cracking Units

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Continuous Compliance With Operating Limits for Metal HAP Emissions From Catalytic Cracking Units 7 Table 7 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS...

  7. 40 CFR Table 4 to Subpart Uuu of... - Requirements for Performance Tests for Metal HAP Emissions From Catalytic Cracking Units Not...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Requirements for Performance Tests for Metal HAP Emissions From Catalytic Cracking Units Not Subject to the New Source Performance Standard (NSPS) for Particulate Matter (PM) 4 Table 4 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)...

  8. Transportation fuel production by combination of LDPE thermal cracking and catalytic hydroreforming.

    PubMed

    Escola, J M; Aguado, J; Serrano, D P; Briones, L

    2014-11-01

    Fuel production from plastics is a promising way to reduce landfilling rates while obtaining valuable products. The usage of Ni-supported hierarchical Beta zeolite (h-Beta) for the hydroreforming of the oils coming from LDPE thermal cracking has proved to produce high selectivities to gasoline and diesel fuels (>80%). In the present work, the effect of the Ni loading on Ni/h-Beta is investigated in the hydroreforming of the oils form LDPE thermal cracking. h-Beta samples were impregnated with Ni nitrate, calcined and reduced in H2 up to 550°C to achieve different Ni contents: 1.5%, 4%, 7% and 10%. Larger and more easily reducible metal particles were obtained on Ni 7%/h-Beta and Ni 10%/h-Beta. Hydroreforming tests were carried out in autoclave reactor at 310°C, under 20 bar H2, for 45 min. Ni content progressively increased the amount of gases at the expenses of diesel fractions, while gasoline remained approximately constant about 52-54%. Maximum selectivity to automotive fuels (∼81%) was obtained with Ni 7%/h-Beta. Ni loading also enhanced olefins saturation up to Ni 7%/h-Beta. High cetane indices (71-86) and octane numbers (89-91) were obtained over all the catalysts. Regarding the different studied Ni contents, Ni 7%/h-Beta constitutes a rather promising catalyst for obtaining high quality fuels from LDPE thermal cracking oils. PMID:25027227

  9. Transportation fuel production by combination of LDPE thermal cracking and catalytic hydroreforming

    SciTech Connect

    Escola, J.M.; Briones, L.

    2014-11-15

    Highlights: • h-Beta samples were impregnated with Ni nitrate to achieve Ni contents of 1.5%, 4%, 7% and 10%. • Larger and more easily reducible metal particles were obtained on Ni 7%/h-Beta and Ni 10%/h-Beta. • Higher Ni contents increased the amount of gases at the expenses of diesel fractions. • Maximum selectivity to automotive fuels (∼81%) was obtained with Ni 7%/h-Beta. • Ni loading also enhanced olefins saturation up to Ni 7%/h-Beta. - Abstract: Fuel production from plastics is a promising way to reduce landfilling rates while obtaining valuable products. The usage of Ni-supported hierarchical Beta zeolite (h-Beta) for the hydroreforming of the oils coming from LDPE thermal cracking has proved to produce high selectivities to gasoline and diesel fuels (>80%). In the present work, the effect of the Ni loading on Ni/h-Beta is investigated in the hydroreforming of the oils form LDPE thermal cracking. h-Beta samples were impregnated with Ni nitrate, calcined and reduced in H{sub 2} up to 550 °C to achieve different Ni contents: 1.5%, 4%, 7% and 10%. Larger and more easily reducible metal particles were obtained on Ni 7%/h-Beta and Ni 10%/h-Beta. Hydroreforming tests were carried out in autoclave reactor at 310 °C, under 20 bar H{sub 2}, for 45 min. Ni content progressively increased the amount of gases at the expenses of diesel fractions, while gasoline remained approximately constant about 52–54%. Maximum selectivity to automotive fuels (∼81%) was obtained with Ni 7%/h-Beta. Ni loading also enhanced olefins saturation up to Ni 7%/h-Beta. High cetane indices (71–86) and octane numbers (89–91) were obtained over all the catalysts. Regarding the different studied Ni contents, Ni 7%/h-Beta constitutes a rather promising catalyst for obtaining high quality fuels from LDPE thermal cracking oils.

  10. The Catalytic Cracking of Hydrocarbons: Paraffins in the HZSM-5 Zeolite

    SciTech Connect

    Martinez-Magadan, Jose M.; Mercado, Sergio M.; Santamaria, Ruben

    2001-11-19

    An elementary reaction during cracking of a hydrocarbon in a nanoporous silicalite catalyst includes ejection of a hydrid ion as shown in the picture. The reaction was simulated by means of quantum molecular dynamics. The central goal of petroleum refineries consists in the transformation of crude oil into a variety of useful products, among which fuels play a crucial role.[1] Presently, important companies are using state-of-the-art technology to investigate new and more efficient refining processes, that may additionally lead to a cleaner environment. Unfortunately, this type of investigation demands costly investment and is highly empirical[2, 3] due to the number of variables, properties, and pathways that characterize the refining processes. On the other hand, the intense competition among catalyst manufacturers has challenged basic research.

  11. The Use of Fry (Embalming Fluid and PCP-Laced Cigarettes or Marijuana Sticks) among Crack Cocaine Smokers

    ERIC Educational Resources Information Center

    Peters, Ronald J.; Williams, Mark; Ross, Michael W.; Atkinson, John; McCurdy, Sherly A.

    2009-01-01

    Statistics show that the prevalence of crack cocaine use and embalming fluid and phencyclidine (PCP)-laced cigarettes or marijuana sticks, commonly referred to on the street as "fry" or "wet" is a problem; however, the relationship between these substances of abuse and concurrent polydrug use is unknown. In the present study, a cross-sectional…

  12. Catalytic cracking of HDPE wastes to liquid fuel in the presence of siliceous mesoporous molecular sieves

    NASA Astrophysics Data System (ADS)

    Ramli, Anita; Majid, Noor Diana Abdul; Yusup, Suzana

    2014-10-01

    A siliceous gel was synthesized at 80°C and aged for 5 days at 120°C before it was dried at 120°C for 16 hours and calcined at 500 and 700°C. The calcined Na-Si-MMS samples were then undergone ion exchange with ammonia solution to form NH4- Si - MMS . All samples were characterized for their physicochemical properties using nitrogen (N2) adsorption-desorption isotherm for surface area and porosity; and temperature programme desorption of ammonia (TPD-NH3) for determination of acidity. The catalytic activity of all samples was tested in pyrolysis of high density polyethylene (HDPE) waste at catalyst to HDPE ratio of 0.2. The organic liquid product (OLP) collected was analysed using gas chromatography (GC). Results show that presence of Na-Si-MMS calcined at 500°C promotes the formation of gasoline-like product while presence of Na-Si-MMS calcined at 700°C promotes the formation of both diesel-like and kerosene-like products. On the other hand, presence of all NH4-Si-MMS catalysts promotes the formation of gasoline-like product. These show that the activation process of Si-MMS has a significant effect on the production of fuel-like product from pyrolysis of HDPE.

  13. Catalytic cracking of non-edible sunflower oil over ZSM-5 for hydrocarbon bio-jet fuel.

    PubMed

    Zhao, Xianhui; Wei, Lin; Julson, James; Qiao, Qiquan; Dubey, Ashish; Anderson, Gary

    2015-03-25

    Non-edible sunflower oils that were extracted from sunflower residual wastes were catalytically cracked over a ZSM-5 catalyst in a fixed-bed reactor at three different reaction temperatures: 450°C, 500°C and 550°C. The catalyst was characterized using XRD, FT-IR, BET and SEM. Characterizations of the upgraded sunflower oils, hydrocarbon fuels, distillation residues and non-condensable gases were carried out. The effect of the reaction temperature on the yield and quality of liquid products was discussed. The results showed that the reaction temperature affected the hydrocarbon fuel yield but had a minor influence on its properties. The highest conversion efficiency from sunflower oils to hydrocarbon fuels was 30.1%, which was obtained at 550°C. The reaction temperature affected the component content of the non-condensable gases. The non-condensable gases generated at 550°C contained the highest content of light hydrocarbons (C1-C5), CO, CO2 and H2. Compared to raw sunflower oils, the properties of hydrocarbon fuels including the dynamic viscosity, pH, moisture content, density, oxygen content and heating value were improved. PMID:25639196

  14. Life cycle assessment of hydrogenated biodiesel production from waste cooking oil using the catalytic cracking and hydrogenation method.

    PubMed

    Yano, Junya; Aoki, Tatsuki; Nakamura, Kazuo; Yamada, Kazuo; Sakai, Shin-ichi

    2015-04-01

    There is a worldwide trend towards stricter control of diesel exhaust emissions, however presently, there are technical impediments to the use of FAME (fatty acid methyl esters)-type biodiesel fuel (BDF). Although hydrogenated biodiesel (HBD) is anticipated as a new diesel fuel, the environmental performance of HBD and its utilization system have not been adequately clarified. Especially when waste cooking oil is used as feedstock, not only biofuel production but also the treatment of waste cooking oil is an important function for society. A life cycle assessment (LCA), including uncertainty analysis, was conducted to determine the environmental benefits (global warming, fossil fuel consumption, urban air pollution, and acidification) of HBD produced from waste cooking oil via catalytic cracking and hydrogenation, compared with fossil-derived diesel fuel or FAME-type BDF. Combined functional unit including "treatment of waste cooking oil" and "running diesel vehicle for household waste collection" was established in the context of Kyoto city, Japan. The calculation utilized characterization, damage, and integration factors identified by LIME2, which was based on an endpoint modeling method. The results show that if diesel vehicles that comply with the new Japanese long-term emissions gas standard are commonly used in the future, the benefit of FAME-type BDF will be relatively limited. Furthermore, the scenario that introduced HBD was most effective in reducing total environmental impact, meaning that a shift from FAME-type BDF to HBD would be more beneficial. PMID:25670164

  15. Robust regulation of temperature in reactor-regenerator fluid catalytic cracking units

    SciTech Connect

    Alvarez-Ramirez, J.; Aguilar, R.; Lopez-Isunza, F.

    1996-05-01

    FCC processes involve complex interactive dynamics which are difficult to operate and control as well as poorly known reaction kinetics. This work concerns the synthesis of temperature controllers for FCC units. The problem is addressed first for the case where perfect knowledge of the reaction kinetics is assumed, leading to an input-output linearizing state feedback. However, in most industrial FCC units, perfect knowledge of reaction kinetics and composition measurements is not available. To address the problem of robustness against uncertainties in the reaction kinetics, an adaptive model-based nonlinear controller with simplified reaction models is presented. The adaptive strategy makes use of estimates of uncertainties derived from calorimetric (energy) balances. The resulting controller is similar in form to standard input-output linearizing controllers and can be tuned analogously. Alternatively, the controller can be tuned using a single gain parameter and is computationally efficient. The performance of the closed-loop system and the controller design procedure are shown with simulations.

  16. Dynamic bulk and shear moduli due to grain-scale local fluid flow in fluid-saturated cracked poroelastic rocks: Theoretical model

    NASA Astrophysics Data System (ADS)

    Song, Yongjia; Hu, Hengshan; Rudnicki, John W.

    2016-07-01

    Grain-scale local fluid flow is an important loss mechanism for attenuating waves in cracked fluid-saturated poroelastic rocks. In this study, a dynamic elastic modulus model is developed to quantify local flow effect on wave attenuation and velocity dispersion in porous isotropic rocks. The Eshelby transform technique, inclusion-based effective medium model (the Mori-Tanaka scheme), fluid dynamics and mass conservation principle are combined to analyze pore-fluid pressure relaxation and its influences on overall elastic properties. The derivation gives fully analytic, frequency-dependent effective bulk and shear moduli of a fluid-saturated porous rock. It is shown that the derived bulk and shear moduli rigorously satisfy the Biot-Gassmann relationship of poroelasticity in the low-frequency limit, while they are consistent with isolated-pore effective medium theory in the high-frequency limit. In particular, a simplified model is proposed to quantify the squirt-flow dispersion for frequencies lower than stiff-pore relaxation frequency. The main advantage of the proposed model over previous models is its ability to predict the dispersion due to squirt flow between pores and cracks with distributed aspect ratio instead of flow in a simply conceptual double-porosity structure. Independent input parameters include pore aspect ratio distribution, fluid bulk modulus and viscosity, and bulk and shear moduli of the solid grain. Physical assumptions made in this model include (1) pores are inter-connected and (2) crack thickness is smaller than the viscous skin depth. This study is restricted to linear elastic, well-consolidated granular rocks.

  17. 40 CFR 60.105a - Monitoring of emissions and operations for fluid catalytic cracking units (FCCU) and fluid coking...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... with the approved alternative for monitoring exhaust gas flow rate in 40 CFR 63.1573(a) of the National... each CO2, O2, and CO monitor according to the requirements in § 60.13(c) and Performance Specification... atmosphere from each FCCU and FCU subject to the CO emissions limit in § 60.102a(b)(4). (1) The owner...

  18. 40 CFR 60.105a - Monitoring of emissions and operations for fluid catalytic cracking units (FCCU) and fluid coking...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... monitoring exhaust gas flow rate in 40 CFR 63.1573(a) of the National Emission Standards for Hazardous Air... to part 60. (ii) The owner or operator shall conduct performance evaluations of each CO2, O2 and CO... part 60, including quarterly accuracy determinations for CO2 and CO monitors, annual...

  19. 40 CFR 60.105a - Monitoring of emissions and operations for fluid catalytic cracking units (FCCU) and fluid coking...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... monitoring exhaust gas flow rate in 40 CFR 63.1573(a) of the National Emission Standards for Hazardous Air... to part 60. (ii) The owner or operator shall conduct performance evaluations of each CO2, O2 and CO... part 60, including quarterly accuracy determinations for CO2 and CO monitors, annual...

  20. 40 CFR 60.105a - Monitoring of emissions and operations for fluid catalytic cracking units (FCCU) and fluid coking...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... with the approved alternative for monitoring exhaust gas flow rate in 40 CFR 63.1573(a) of the National... each CO2, O2, and CO monitor according to the requirements in § 60.13(c) and Performance Specification... atmosphere from each FCCU and FCU subject to the CO emissions limit in § 60.102a(b)(4). (1) The owner...

  1. 40 CFR 60.105a - Monitoring of emissions and operations for fluid catalytic cracking units (FCCU) and fluid coking...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... with the approved alternative for monitoring exhaust gas flow rate in 40 CFR 63.1573(a) of the National... each CO2, O2, and CO monitor according to the requirements in § 60.13(c) and Performance Specification... atmosphere from each FCCU and FCU subject to the CO emissions limit in § 60.102a(b)(4). (1) The owner...

  2. Primary migration of hydrocarbon fluids through invasion-percolation cracking in a source rock

    NASA Astrophysics Data System (ADS)

    Kobchenko, M.; Panahi, H.; Renard, F.; Malthe-Sorenssen, A.; Scheibert, J.; Dysthe, D.; Meakin, P.

    2010-12-01

    A petroleum source rock is a tightly bound mixture of highly viscous, high molecular weight, organics (kerogen) and inorganic sedimentary material. During burial, as the temperature and pressure increase, kerogen decomposes, and low viscosity, low molecular weight, hydrocarbons are generated. Primary migration has been studied for decades, but it still remains an enigma how the generated gas and oil escape from very low permeable shales into secondary migration pathways. There is strong evidence that microfractures play an important role in this process. In order to observe crack nucleation and development we performed high resolution x-ray microtomography experiments on samples of Mahogany Zone Green River Shale (Peance Basin, Colorado, USA). One sample was exposed to a gradual rising temperature under atmospheric pressure and time-lapse 3D images of void formation and cracking were acquired. We show that crack formation occurs via nucleation of small cracks/voids located on kerogen patches initially present in the samples. Then these cracks propagate through an invasion percolation-like process in which the fracture front incrementally moves by local stress relaxation. Finally, the small cracks merge progressively until they span the whole sample.

  3. THE USE OF FRY (EMBALMING FLUID AND PCP-LACED CIGARETTES OR MARIJUANA STICKS) AMONG CRACK COCAINE SMOKERS

    PubMed Central

    PETERS, RONALD J.; WILLIAMS, MARK; ROSS, MICHAEL W.; ATKINSON, JOHN; McCURDY, SHERLY A.

    2010-01-01

    Statistics show that the prevalence of crack cocaine use and embalming fluid and phencyclidine (PCP)-laced cigarettes or marijuana sticks, commonly referred to on the street as “fry” or “wet” is a problem; however, the relationship between these substances of abuse and concurrent polydrug use is unknown. In the present study, a cross-sectional survey was conducted among 426 African-American crack users in Houston, Texas, to investigate the difference between those who concurrently reported lifetime (defined as at least one usage of fry in life) fry use and those who stated they never used fry. The data were analyzed using chi-square and logistic regression analyses. Fry users were significantly more likely than non-users to not have a casual sex partner (92% users vs. 84% non-users, p ≤ 0.05) and were more likely to have been diagnosed with gonorrhea in the past 12 months (9% users vs. 2% non-users, p ≤ 0.05). In addition fry users had significantly higher odds of currently trading sex for drugs (OR = 2.30, p ≤ 0.05), marijuana use (OR = 12.11, p ≤ 0.05), and codeine (syrup) use (OR = 8.10, p ≤ 0.05). These findings are important in determining the “cultural novelties” relative to crack and fry use among younger African Americans. PMID:19157045

  4. Resonance of a fluid-driven crack: radiation properties and implications for the source of long-period events and harmonic tremor.

    USGS Publications Warehouse

    Chouet, B.

    1988-01-01

    A dynamic source model is presented, in which a 3-D crack containing a viscous compressible fluid is excited into resonance by an impulsive pressure transient applied over a small area DELTA S of the crack surface. The crack excitation depends critically on two dimensionless parameters called the crack stiffness and viscous damping loss. According to the model, the long-period event and harmonic tremor share the same source but differ in the boundary conditions for fluid flow and in the triggering mechanism setting up the resonance of the source, the former being viewed as the impulse response of the tremor generating system and the later representing the excitation due to more complex forcing functions.-from Author

  5. A fully coupled porous flow and geomechanics model for fluid driven cracks: a peridynamics approach

    NASA Astrophysics Data System (ADS)

    Ouchi, Hisanao; Katiyar, Amit; York, Jason; Foster, John T.; Sharma, Mukul M.

    2015-03-01

    A state-based non-local peridynamic formulation is presented for simulating fluid driven fractures in an arbitrary heterogeneous poroelastic medium. A recently developed peridynamic formulation of porous flow has been coupled with the existing peridynamic formulation of solid and fracture mechanics resulting in a peridynamic model that for the first time simulates poroelasticity and fluid-driven fracture propagation. This coupling is achieved by modeling the role of pore pressure on the deformation of porous media and vice versa through porosity variation with medium deformation, pore pressure and total mean stress. The poroelastic model is verified by simulating the one-dimensional consolidation of fluid saturated rock. An additional porous flow equation with material permeability dependent on fracture width is solved to simulate fluid flow in the fractured region. Finally, single fluid-driven fracture propagation with a two-dimensional plane strain assumption is simulated and verified against the corresponding classical analytical solution.

  6. Flow of Compressible Fluids Through Cracks in Elastic Bodies and Excitation of Volcanic Tremor

    NASA Astrophysics Data System (ADS)

    Dunham, E. M.; Ogden, D. E.

    2010-12-01

    We investigate the eruption of fluids through conduits in elastic bodies, with particular focus on the excitation of seismic waves by conduit wall oscillations induced by fluid flow. The models are presently two-dimensional with plane strain elastic response, such that the conduits most closely represent magma-filled dikes. The fluid response is idealized using quasi-one-dimensional mass and momentum balance equations for isothermal compressible flows, including both gravity and frictional drag. The mixture of exsolved gas and liquid melt is treated as a single phase fluid with an equation of state that captures the extreme changes in compressibility that occur as gas exsolves. Both the elastic wave equation and the fluid equations are solved with high order finite differences. The fluid and solid response is fully coupled: elastic deformation changes the cross-sectional area of the conduit through which fluid flows, and changes in fluid pressure push the conduit walls in and out. Because elastic wave speeds are nearly an order of magnitude faster than the fluid sound speed, elastic equilibrium is approached very rapidly over the time scale of fluid flow. We have conducted a preliminary study of a dike filled with overpressurized magma breaking Earth's surface. Contact with the much lower atmospheric pressure at the surface drives a rarefaction down into fluid at the fluid sound speed; in the rarefaction, fluid pressure drops and gas exsolves. This induces a suction on the conduit walls that pulls them together. The reduction in conduit width occurs not only within the rarefaction, but also ahead of it due to the nearly instantaneous elastic response. This compresses the fluid ahead of the rarefaction, increasing its pressure. The resulting pressure gradient decelerates the rarefaction and appears to limit the depth extent to which the gas exsolution processes occurs (at least over short time scales). We also see that as the rarefaction continues to propagate, the

  7. Shuttle Fuel Feedliner Cracking Investigation

    NASA Technical Reports Server (NTRS)

    Nesman, Tomas E.; Turner, Jim (Technical Monitor)

    2002-01-01

    This presentation provides an overview of material covered during 'Space Shuttle Fuel Feedliner Cracking Investigation MSFC Fluids Workshop' held November 19-21, 2002. Topics covered include: cracks on fuel feed lines of Orbiter space shuttles, fluid driven cracking analysis, liner structural modes, structural motion in a fluid, fluid borne drivers, three dimensional computational fluid dynamics models, fluid borne drivers from pumps, amplification mechanisms, flow parameter mapping, and flight engine flow map.

  8. Heterogeneous kinetic modeling of the catalytic conversion of cycloparaffins

    NASA Astrophysics Data System (ADS)

    Al-Sabawi, Mustafa N.

    The limited availability of high value light hydrocarbon feedstocks along with the rise in crude prices has resulted in the international recognition of the vast potential of Canada's oil sands. With the recent expansion of Canadian bitumen production come, however, many technical challenges, one of which is the significant presence of aromatics and cycloparaffins in bitumen-derived feedstocks. In addition to their negative environmental impact, aromatics limit fluid catalytic cracking (FCC) feedstock conversion, decrease the yield and quality of valuable products such as gasoline and middle distillates, increase levels of polyaromatic hydrocarbons prone to form coke on the catalyst, and ultimately compromise the FCC unit performance. Although cycloparaffins do not have such negative impacts, they are precursors of aromatics as they frequently undergo hydrogen transfer reactions. However, cycloparaffin cracking chemistry involves other competing reactions that are complex and need much investigation. This dissertation provides insights and understanding of the fundamentals of the catalytic cracking of cycloparaffins using carefully selected model compounds such as methylcyclohexane (MCH) and decalin. Thermal and catalytic cracking of these cycloparaffins on FCC-type catalysts are carried out using the CREC Riser Simulator under operating conditions similar to those of the industrial FCC units in terms of temperature, reaction time, reactant partial pressure and catalyst-to-hydrocarbon ratio. The crystallite size of the supported zeolites is varied between 0.4 and 0.9 microns, with both activity and selectivity being monitored. Catalytic conversions ranged between 4 to 16 wt% for MCH and between 8 to 27 wt% for decalin. Reaction pathways of cycloparaffins are determined, and these include ring-opening, protolytic cracking, isomerization, hydrogen transfer and transalkylation. The yields and selectivities of over 60 and 140 products, formed during MCH and decalin

  9. Dual function cracking catalyst (DFCC) composition

    SciTech Connect

    Occelli, M.L.

    1986-10-07

    The patent describes a novel catalytic cracking composition comprising a cracking catalyst having high activity and, as a separate and distinct entity, a diluent comprising a substantially catalytically inactive crystalline aluminosilicte having a fresh MAT Activity below about 1. The diluent is clinoptilolite and the cracking catalyst contains a rare earth-exchanged crystalline aluminium silicate. The cracking catalyst comprises from about ten to about 60 weight percent of a zeolite having cracking characteristics dispersed in a refractory metal oxide matrix.

  10. Influence of circumferential notch and fatigue crack on the mechanical integrity of biodegradable magnesium-based alloy in simulated body fluid.

    PubMed

    Bobby Kannan, M; Singh Raman, R K; Witte, F; Blawert, C; Dietzel, W

    2011-02-01

    Applications of magnesium alloys as biodegradable orthopaedic implants are critically dependent on the mechanical integrity of the implant during service. In this study, the mechanical integrity of an AZ91 magnesium alloy was studied using a constant extension rate tensile (CERT) method. The samples in two different geometries that is, circumferentially notched (CN), and circumferentially notched and fatigue cracked (CNFC), were tested in air and in simulated body fluid (SBF). The test results show that the mechanical integrity of the AZ91 magnesium alloy decreased substantially (∼50%) in both the CN and CNFC samples exposed to SBF. Fracture surface analysis revealed secondary cracks suggesting stress corrosion cracking susceptibility of the alloy in SBF. PMID:21210510

  11. Low-temperature, selective catalytic deoxygenation of vegetable oil in supercritical fluid media.

    PubMed

    Kim, Seok Ki; Lee, Hong-Shik; Hong, Moon Hyun; Lim, Jong Sung; Kim, Jaehoon

    2014-02-01

    The effects of supercritical fluids on the production of renewable diesel-range hydrocarbons from natural triglycerides were investigated. Various supercritical fluids, which included CO2 (scCO2 ), propane (scC3 H8 ) and n-hexane (scC6 H14 ), were introduced with H2 and soybean oil into a fixed-bed reactor that contained pre-activated CoMo/γ-Al2 O3 . Among these supercritical fluids, scC3 H8 and scC6 H14 efficiently allowed the reduction of the reaction temperature by as much as 50 °C as a result of facilitated heat and mass transfer and afforded similar yields to reactions in the absence of supercritical fluids. The compositional analyses of the gas and liquid products indicated that the addition of scC3 H8 during the hydrotreatment of soybean oil promoted specific deoxygenation pathways, decarbonylation and decarboxylation, which consumed less H2 than the hydrodeoxygenation pathway. As a result, the quantity of H2 required to obtain a high yield of diesel-range hydrocarbons could be reduced to 57 % if scC3 H8 was used. As decarboxylation and decarbonylation are mildly endothermic reactions, the reduced heat transfer resistance in scC3 H8 may drive the deoxygenation reaction to thermodynamically favourable pathways. PMID:24339322

  12. Prediction of cracks in continuously cast steel beam blank through fully coupled analysis of fluid flow, heat transfer, and deformation behavior of a solidifying shell

    SciTech Connect

    Lee, J.E.; Yeo, T.J.; Oh, K.H.; Yoon, J.K.; Yoon, U.S.

    2000-01-01

    A mathematical model has been developed for the prediction of cracks in the continuously cast steel beam blank through the fully coupled analysis of fluid flow, heat transfer, and deformation behavior of a solidifying shell. Fluid flow and heat transfer in the strand mold were analyzed with a three-dimensional (3-D) finite-volume method (FVM). For the complex geometry of the beam blank, a body-fitted coordinate (BFC) system was employed, Thermo-elastic-plastic deformation behavior in the strand was analyzed using the finite-element method (FEM) based on the two-dimensional (2-D) slice model. The thermal fields of the strand calculated with the FVM were used in the analysis of the deformation behavior of the strand. Through the iterative analysis of the fluid flow, heat-transfer, and deformation behavior, the coupling parameter of the heat-transfer coefficient between the strand and the mold was obtained. In order to describe the thermophysical properties and thermomechanical behavior of steel in the mushy zone, the microsegregation of solute elements was assessed. Consequently, some characteristic temperatures of steel as well as variations of phase fractions with temperature were determined. The probability of cracking in the strand, originating form an interdendritic liquid film, was quantified as a crack susceptibility coefficient. Recirculating flows were developed in the web and flange-tip regions. The development of a solidifying shell in the flange-center region was retarded by the inlet flow from a submerged entry nozzle (SEN). An air gap was formed mainly near the flange-tip corner. Surface cracks in the web and fillet regions and internal cracks in the flange-tip region were predicted.

  13. Computer simulations of fluid flow over catalytic surfaces for water splitting

    NASA Astrophysics Data System (ADS)

    Chong, Leebyn; Dutt, Meenakshi

    2014-12-01

    Interfacial phenomena arising at solid/fluid interfaces depend upon the nanoscale structural and dynamical properties of the system. The presence of active sites on the solid surface that can bind with reactants in the fluid enables the investigation of reaction kinetics and its effect on multi-scale transport processes. We develop a coarse-grained particle-based model of the flow of reactants over a solid surface composed of close packed particles with embedded active sites. We investigate the role of the adsorption of the reactants onto these sites on the transport phenomena via the coarse-grained molecular dynamics technique. Our objective is to understand the role of nanoscale interfacial phenomena on the structural and dynamical properties of the system through the measurement of diffusion coefficients, velocity profiles, radial distribution functions, and mean residence times. We have investigated these properties as a function of the active site density, coarse graining effects and interaction strengths. Our results can potentially be used for future studies on multi-scale phenomena driven by reaction kinetics at solid/fluid interfaces, such as artificial photosynthesis cells.

  14. Catalytic ozonation of phenolic wastewater with activated carbon fiber in a fluid bed reactor.

    PubMed

    Qu, Xianfeng; Zheng, Jingtang; Zhang, Yanzong

    2007-05-15

    The effect of activated carbon fiber (ACF) on the ozonation of phenol in water in a fluid bed reactor was investigated. It was observed that this combined process could increase the yield of the oxidation process significantly for phenol and COD (chemical oxygen demand) removal, especially for the phenol removal. The efficiency of ozonation increased with an increase in the dose of ACF. Higher initial phenol concentration only caused a slight decrease of phenol and COD removal. The results of repeated use found that ozonation could efficiently regenerate ACF in situ in the reactor, which was considered easy to handle without the costly ex situ regeneration of the industrial treatment process. The Boehm titrations and FTIR studies indicate that the ozonation process in water can significantly change the composition of acidic surface oxygen-containing groups of ACF, leading to the increase of carboxylic, hydroxylic, and carbonylic groups and the slight decrease of the lactonic groups. Furthermore, this process can also increase the surface area and total pore volume of ACF. Due to the new micropore formation and some pore enlargement, the micropores became smaller, and the mesopores and macropores got bigger. PMID:17336995

  15. Giant strain-sensitivity of local acoustic dissipation near inner wavy contacts in dry and fluid-saturated cracks

    NASA Astrophysics Data System (ADS)

    Zaitsev, V. Yu.; Matveev, L. A.

    2012-05-01

    Presently, experimental evidence for extremely high strain-sensitivity of dissipation in rocks and similar microstructured materials is obtained both in laboratory and field conditions, in particular observations of pronounced amplitude modulation of the radiation of high-stability seismo-acoustic sources by tidal deformations of rocks with typical strains ~ 10-8. Such data indicate the presence of some thresholdless in amplitude and very efficient mechanism of strain-dependent dissipation. Conventionally, its origin is discussed in the context of frictional or adhesion-hysteretic loss at cracks in rocks. However, such dissipation mechanisms are not relevant to weak perturbations with displacements smaller than atomic size. Here, we revise thresholdless thermoelastic loss in dry cracks and viscous loss in saturated cracks taking into account wavy asperities typical of real cracks, which can create elongated (strip-like) contacts or almost closed "waists" in cracks. Thermoelastic loss at these contacts can be very efficient. Besides, the state of such contacts can already be strongly perturbed by the average strain which yet practically does not change the mean opening of the entire crack. Thus the dissipation localized at such contacts can be significantly affected by quite small average strain (e.g., 10-8), which is usually believed to be unable to produce any appreciable effect on the dissipation. Next, for liquid-saturated cracks, the presence of inner elongated asperities also drastically changes the character of squirt-type viscous dissipation. Velocity gradients and consequently the dissipation are localized in the vicinity of the nearly-closed waists which almost harness the liquid flow in the crack. This dissipation can be comparable in magnitude with viscous dissipation at the entire crack with smooth interface, but the decrement maximum is strongly shifted downwards on the frequency axis. Since near the waist the gap is much smaller than the average crack

  16. Carbonate-type cracking in an FCC Wet gas compressor station

    SciTech Connect

    Mirabel, E. ); Bhattacharjee, S. , P.O. Box 3843, Curacao ); Pazos, N. )

    1991-07-01

    The petroleum refinery industry is becoming increasingly aware of hydrogen-related damage that can be induced by wet hydrogen sulfide (H{sub 2}S) and amine on equipment and piping fabricated from carbon and low-alloy steel. This paper reports that cracking of second-stage knock-out drum of a fluid catalytic cracking wet gas compressor station has been studied. Carbonate-type cracking mechanism in carbon steel has been identified as responsible for the intergranular and branched cracks that produced the leakage of the vessel. The gas containing CO{sub 2}, H{sub 2}S, ammonia, and cyanides, plus water and sludge trapped in the gas inlet support, assisted by stress concentration due to welding configuration, have been identified as responsible for such a type of cracking.

  17. Strategies for catalytic octane enhancement in an FCC unit

    SciTech Connect

    Creighton, J.E.; Edwards, G.C.; Rajagopalan, K.; Peters, A.W.; Young, G.W. )

    1987-08-01

    Gasoline quality is largely determined by motor and research octane numbers. There is good correlation between octane number and the structure of the C{sub 5} to C{sub 12} hydrocarbons typically present in gasoline. For paraffins, octane number decreases as molecular weight increases with degree of branching. The same is true of olefins. Catalytic strategies for making high octane gasolines include decreasing the amount of higher molecular weight, less branched paraffins, isomerizing paraffins to a more highly branched product, and producing more olefins or aromatics. A number of catalytic processes in current use make use of these strategies, including reforming, isomerization, dimerization, alkylation and fluid catalytic cracking (FCC). The subject of this paper is to discuss the catalytic strategies available to produce octane number in the FCC unit.

  18. Slow Crack Growth and Fracture Toughness of Sapphire for the International Space Station Fluids and Combustion Facility

    NASA Technical Reports Server (NTRS)

    Salem, Jonathan A.

    2006-01-01

    The fracture toughness, inert flexural strength, and slow crack growth parameters of the r- and a-planes of sapphire grown by the Heat Exchange Method were measured to qualify sapphire for structural use in the International Space Station. The fracture toughness in dry nitrogen, K(sub Ipb), was 2.31 +/- 0.12 MPa(square root of)m and 2.47 +/- 0.15 MPa(squre root of)m for the a- and r-planes, respectively. Fracture toughness measured in water via the operational procedure in ASTM C1421 was significantly lower, K(sub Ivb) = 1.95+/- 0.03 MPa(square root of)m, 1.94 +/- 0.07 and 1.77 +/- 0.13 MPa(square root of)m for the a- , m- and r-planes, respectively. The mean inert flexural strength in dry nitrogen was 1085 +/- 127 MPa for the r-plane and 1255 +/- 547 MPa for the a-plane. The power law slow crack growth exponent for testing in water was n = 21 +/- 4 for the r-plane and n (greater than or equal to) 31 for the a-plane. The power law slow crack growth coefficient was A = 2.81 x 10(exp -14) m/s x (MPa(squre root of)m)/n for the r-plane and A (approx. equals)2.06 x 10(exp -15) m/s x (MPa(square root of)m)/n for the a-plane. The r- and a-planes of sapphire are relatively susceptible to stress corrosion induced slow crack growth in water. However, failure occurs by competing modes of slow crack growth at long failure times and twinning for short failure time and inert environments. Slow crack growth testing needs to be performed at low failure stress levels and long failure times so that twinning does not affect the results. Some difficulty was encountered in measuring the slow crack growth parameters for the a-plane due to a short finish (i.e., insufficient material removal for elimination of the damage generated in the early grinding stages). A consistent preparation method that increases the Weibull modulus of sapphire test specimens and components is needed. This would impart higher component reliability, even if higher Weibull modulus is gained at the sacrifice of

  19. The selective catalytic cracking of Fischer-Tropsch liquids to high value transportation fuels. Report number 30: Quarterly technical status report for second quarter fiscal year 1993 (January 1--March 31, 1993)

    SciTech Connect

    Schwartz, M.M.

    1993-12-31

    Amoco Oil Company is investigating a selective catalytic cracking process to convert the Fischer-Tropsch gasoline and wax fractions to high value transportation fuels. Experiments with the LaPorte wax as feedstock demonstrated the feasibility of the concept of selective attrition of the FCC catalyst. Experiments comparing the Sasol and LaPorte wax feedstocks with USY, Beta and HZSM-5 catalysts showed that the type of FCC catalyst has a major impact upon product yields and quality. For a given catalyst, both feedstocks have similar conversion values. The yields of the major catalytic cracking products, light olefins, naphtha and distillate, do not vary significantly with the two wax feedstocks. The methanol etherification of the light naphtha product from the pilot plant F-T wax cracking runs yields a mixed ether product. Etherification runs were completed on two additional pilot plant light naphthas using two commercial etherification catalysts, one of which contains a noble metal, in addition to the strong acid functionality. Isoolefin conversion values were similar for the two catalysts and three feedstocks in the absence of H{sub 2}. With H{sub 2} present, product color is improved; but overall the presence of H{sub 2} is not desirable because olefins are saturated, which results in decreased production of ethers and decreased product octane number. Economic analysis of the eight pilot plant runs that were performed under Task 4 showed that the net production values for a complex refinery were always higher than for a simple refinery (no ether unit).

  20. Cracking process with catalyst of combined zeolites

    SciTech Connect

    Gladrow, E. M.; Winter, W. E.

    1981-09-01

    A hydrocarbon cracking catalyst comprises an ultrastable y-type crystalline zeolite, a small pore crystalline zeolite such as mordenite, an inorganic oxide matrix and, optionally, a porous inert component. The cracking catalyst has a high activity and selectivity for the production of high octane naphtha fractions from higher boiling point hydrocarbonaceous oils. Catalytic cracking processes utilizing the catalyst are also provided.

  1. The selective catalytic cracking of Fischer-Tropsch liquids to high value transportation fuels. Report number 23: Quarterly technical progress report for third quarter fiscal year 1992 (April 1--June 30, 1992)

    SciTech Connect

    Reagan, W.J.

    1992-12-31

    Amoco Oil Company is investigating a selective catalytic cracking process to convert the Fischer-Tropsch naphtha and wax fractions to high value transportation fuels. The wax feedstock for this program, a commercial sample of Fischer-Tropsch product from Sasol, is a high melting point, (>220 F), high boiling range (50% boiling above 1,000 F), largely paraffinic material. Work this Quarter centers on the study of various types of HZSM-5 and Y zeolite catalysts. The wax cracking tests on the pilot plant unit were completed last Quarter. The initial product yields have now been corrected for gas and liquid component distribution. Several additional product quality measurements have been completed. The distillate product fraction, boiling between 430--650 F, obtained from the Y zeolite catalyst run, has a high quality Cetane Index of 59. These test results also show high conversion (85%+) of the wax feedstock to light gases and gasoline. The ranking of the three zeolite catalyst types for C{sub 4}-C{sub 5} iso-olefin production is similar to the findings of the small scale screening test program. It is not possible to obtain test results at a wide variety of conversion levels on the pilot plant due to operating constraints.

  2. Corrosion cracking

    SciTech Connect

    Goel, V.S.

    1986-01-01

    Various papers on corrosion cracking are presented. The topics addressed include: unique case studies on hydrogen embrittlement failures in components used in aeronautical industry; analysis of subcritical cracking in a Ti-5Al-2.5Sn liquid hydrogen control valve; corrosion fatigue and stress corrosion cracking of 7475-T7351 aluminum alloy; effects of salt water environment and loading frequency on crack initiation in 7075-T7651 aluminum alloy and Ti-6Al-4V; stress corrosion cracking of 4340 steel in aircraft ignition starter residues. Also discussed are: stress corrosion cracking of a titanium alloy in a hydrogen-free environment; automation in corrosion fatigue crack growth rate measurements; the breaking load method, a new approach for assessing resistance to growth of early stage stress corrosion cracks; stress corrosion cracking properties of 2090 Al-Li alloy; repair welding of cracked free machining Invar 36; radial bore cracks in rotating disks.

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

    PubMed

    Wang, Yimeng; Wang, Jie

    2016-08-01

    The pinewood was pyrolyzed in the first reactor at a heating rate of 10°Cmin(-1) from room temperature to 700°C, and the vapor was allowed to be cracked through the second reactor in a temperature range of 450-750°C without and with HZSM-5. Attempts were made to determine a wide spectrum of gaseous and liquid products, as well as the mass and element partitions to gas, water, bio-oil, coke and char. HZSM-5 showed a preferential deoxygenation effect via the facilitated decarbonylation and decarboxylation with the inhibited dehydration at 550-600°C. This catalyst also displayed a high selectivity for the formations of aromatic hydrocarbons and olefins by the promoted hydrogen transfer to these products at 550-600°C. The bio-oil produced with HZSM-5 at 500-600°C had the yields of 14.5-16.8%, the high heat values of 39.1-42.4MJkg(-1), and the energy recoveries of 33-35% (all dry biomass basis). PMID:27209452

  4. The selective catalytic cracking of Fischer-Tropsch liquids to high value transportation fuels. Report number 38: Quarterly technical status report for fourth quarter fiscal year 1993 (July 1--September 30, 1993)

    SciTech Connect

    Schwartz, M.M.

    1993-12-31

    Amoco Oil Company is investigating a selective catalytic cracking process to convert the Fischer-Tropsch gasoline and wax fractions to high value transportation fuels. This report contains the most current and accurate information and projections of the scope of work, schedules, milestones, staffing/manpower plan and costs. Naphtha that was produced by the Liquid Phase F-T demonstration plant at LaPorte, Texas was received and characterized. Three pilot plant runs were completed using Sasol wax as feedstock. The catalysts used were 10% steamed USY, 10% steamed Beta, and standard equilibrium USY. The 10% Beta catalyst gave much higher yields of propylene and butylenes than the USY-based catalysts, in agreement with previous results. Characterization of the IBP-430, 430--650 and 650+ F fractions of these runs is incomplete. The 10% Beta catalyst made 430--650 F product with the highest cetane index (60.9), but the 430--650 F product from all three runs would be excellent stock for blending into diesel fuel.

  5. Hydrocarbon cracking and reforming process

    SciTech Connect

    Le, Q.N.; Schipper, P.H.; Owen, H.

    1992-03-31

    This patent describes a process for upgrading paraffinic naphtha to high octane fuel. It comprises: contacting a fresh naphtha feedstock stream containing a major amount of C{sub 7+} alkanes and naphthenes with medium pore acid cracking catalyst under low pressure selective cracking conditions effective to produce 4-C5 isoalkene and C4-C5 isoalkane, the cracking catalyst being substantially free of hydrogenation-dehydrogenation metal components and having an acid cracking activity less than 15; separating cracking effluent to obtain an olefinic fraction rich in C4-C5 isoalkene and a C6+ fraction; etherifying the C4-C5 isoalkene fraction by catalytic reaction with lower alkanol to produce tertiary-alkyl ether product; and reforming the C6+ fraction to provide high octane gasoline components.

  6. Hydrocarbon cracking with mixture of zeolites y and zsm-5

    SciTech Connect

    Gladrow, E.M.; Winter, W.E.

    1981-09-15

    A hydrocarbon cracking catalyst comprises an ultrastable y-type crystalline zeolite, a small pore crystalline zsm-type zeolite, an inorganic oxide matrix and, optionally, a porous inert component. The cracking catalyst has a high activity and selectivity for the production of high octane naphtha fractions from higher boiling point hydrocarbonaceous oils. Catalytic cracking processes utilizing the catalyst are also provided.

  7. Hydrocarbon cracking catalyst and process utilizing the same

    SciTech Connect

    Gladrow, E.M.; Winter, W.E.

    1980-12-16

    A hydrocarbon cracking catalyst comprises an ultrastable y-type crystalline zeolite, a small pore crystalline zsm-type zeolite, an inorganic oxide matrix and, optionally, a porous inert component. The cracking catalyst has a high activity and selectivity for the production of high octane naphtha fractions from higher boiling point hydrocarbonaceous oils. Catalytic cracking processes utilizing the catalyst are also provided.

  8. Hydrocarbon cracking catalyst and process utilizing the same

    SciTech Connect

    Gladrow, E.M.; Winter, W.E.

    1980-12-30

    A hydrocarbon cracking catalyst comprises an ultrastable y-type crystalline zeolite, a small pore crystalline zeolite such as mordenite, an inorganic oxide matrix and, optionally, a porous inert component. The cracking catalyst has a high activity and selectivity for the production of high octane naphtha fractions from higher boiling point hydrocarbonaceous oils. Catalytic cracking processes utilizing the catalyst are also provided.

  9. Crack Healing in Quartz: Influence of Crack Morphology and pOH-

    NASA Astrophysics Data System (ADS)

    Fallon, J. A.; Kronenberg, A. K.; Popp, R. K.; Lamb, W. M.

    2004-12-01

    Crack healing in quartz has been investigated by optical microscopy and interferometry of rhombohedral r-cleavage cracks in polished Brazilian quartz prisms that were hydrothermally annealed. Quartz prisms were pre-cracked at room temperature and then annealed at temperatures T of 250° and 400° C for 2.4 to 240 hours, fluid pressure Pf = 41 MPa (equal to confining pressure Pc), and varying pOH- (from 5.4 to 1.2 at 250° C for fluids consisting of distilled water and NaOH solutions). Crack morphologies before and after annealing were recorded for each sample in plane light digital images and apertures were determined from interference fringes recorded using transmitted monochromatic light (λ = 598 nm). As documented in previous studies (Smith and Evans, 1984; Brantley et al., 1990; Beeler and Hickman, 1996), crack healing of quartz is driven by reductions in surface energy and healing rates appear to be limited by diffusional solute transport; sharply defined crack tips become blunted and break up into fluid-filled tubes and inclusions. However, fluid inclusion geometries are also observed with nonequilibrium shapes that depend on initial surface roughness. Crack healing is significant at 400° C after short run durations (24 hr) with healing rates reaching 10-5 mm/s. Crack healing is also observed at T=250° C, but only for smooth cracks with apertures < 0.6 μ m or for cracks subject to low pOH-. The extent of crack healing is sensitive to crack aperture and to hackles formed by fine-scale crack branching during crack growth. Initial crack apertures appear to be governed by the presence of fine particles, often found in the vicinity of hackles, which maintain the separation of crack surfaces. Where rough cracks exhibit healing, hackles are sites of either enhanced or reduced loss of fluid-solid interface depending on slight mismatches and sense of twist of opposing crack surfaces. Hackles of open r-cleavage cracks are replaced either by (1) healed curvilinear

  10. Catalytic reactor

    DOEpatents

    Aaron, Timothy Mark; Shah, Minish Mahendra; Jibb, Richard John

    2009-03-10

    A catalytic reactor is provided with one or more reaction zones each formed of set(s) of reaction tubes containing a catalyst to promote chemical reaction within a feed stream. The reaction tubes are of helical configuration and are arranged in a substantially coaxial relationship to form a coil-like structure. Heat exchangers and steam generators can be formed by similar tube arrangements. In such manner, the reaction zone(s) and hence, the reactor is compact and the pressure drop through components is minimized. The resultant compact form has improved heat transfer characteristics and is far easier to thermally insulate than prior art compact reactor designs. Various chemical reactions are contemplated within such coil-like structures such that as steam methane reforming followed by water-gas shift. The coil-like structures can be housed within annular chambers of a cylindrical housing that also provide flow paths for various heat exchange fluids to heat and cool components.

  11. 40 CFR 63.1566 - What are my requirements for organic HAP emissions from catalytic reforming units?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Pollutants for Petroleum Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Catalytic Cracking Units, Catalytic Reforming Units, Sulfur Recovery Units, and Bypass Lines § 63... emission limitations and work practice standards must I meet? You must: (1) Meet each emission...

  12. 40 CFR 63.1566 - What are my requirements for organic HAP emissions from catalytic reforming units?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Pollutants for Petroleum Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Catalytic Cracking Units, Catalytic Reforming Units, Sulfur Recovery Units, and Bypass Lines § 63... emission limitations and work practice standards must I meet? You must: (1) Meet each emission...

  13. 40 CFR 63.1566 - What are my requirements for organic HAP emissions from catalytic reforming units?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Petroleum Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Catalytic Cracking Units, Catalytic Reforming Units, Sulfur Recovery Units, and Bypass Lines § 63.1566 What... limitations and work practice standards must I meet? You must: (1) Meet each emission limitation in Table...

  14. 40 CFR 63.1567 - What are my requirements for inorganic HAP emissions from catalytic reforming units?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Pollutants for Petroleum Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Catalytic Cracking Units, Catalytic Reforming Units, Sulfur Recovery Units, and Bypass Lines § 63... emission limitations and work practice standards must I meet? You must: (1) Meet each emission...

  15. 40 CFR 63.1566 - What are my requirements for organic HAP emissions from catalytic reforming units?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Pollutants for Petroleum Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Catalytic Cracking Units, Catalytic Reforming Units, Sulfur Recovery Units, and Bypass Lines § 63... emission limitations and work practice standards must I meet? You must: (1) Meet each emission...

  16. Crack propagation driven by crystal growth

    SciTech Connect

    A. Royne; Paul Meaking; A. Malthe-Sorenssen; B. Jamtveit; D. K. Dysthe

    2011-10-01

    Crystals that grow in confinement may exert a force on their surroundings and thereby drive crack propagation in rocks and other materials. We describe a model of crystal growth in an idealized crack geometry in which the crystal growth and crack propagation are coupled through the stress in the surrounding bulk solid. Subcritical crack propagation takes place during a transient period, which may be very long, during which the crack velocity is limited by the kinetics of crack propagation. When the crack is sufficiently large, the crack velocity becomes limited by the kinetics of crystal growth. The duration of the subcritical regime is determined by two non-dimensional parameters, which relate the kinetics of crack propagation and crystal growth to the supersaturation of the fluid and the elastic properties of the surrounding material.

  17. Catalytic pyrolysis of oilsand bitumen over nanoporous catalysts.

    PubMed

    Lee, See-Hoon; Heo, Hyeon Su; Jeong, Kwang-Eun; Yim, Jin-Heong; Jeon, Jong-Ki; Jung, Kyeong Youl; Ko, Young Soo; Kim, Seung-Soo; Park, Young-Kwon

    2011-01-01

    The catalytic cracking of oilsand bitumen was performed over nanoporous materials at atmospheric conditions. The yield of gas increased with application of nanoporous catalysts, with the catalytic conversion to gas highest for Meso-MFI. The cracking activity seemed to correlate with pore size rather than weak acidity or surface area. PMID:21446540

  18. Knuckle Cracking

    MedlinePlus

    ... older obese people. Question: Can cracking knuckles / joints lead to arthritis? Answer: There is no evidence of ... or damaged joints due to arthritis could potentially lead more easily to ligament injury or acute trauma ...

  19. Method and apparatus for a catalytic firebox reactor

    DOEpatents

    Smith, Lance L.; Etemad, Shahrokh; Ulkarim, Hasan; Castaldi, Marco J.; Pfefferle, William C.

    2001-01-01

    A catalytic firebox reactor employing an exothermic catalytic reaction channel and multiple cooling conduits for creating a partially reacted fuel/oxidant mixture. An oxidation catalyst is deposited on the walls forming the boundary between the multiple cooling conduits and the exothermic catalytic reaction channel, on the side of the walls facing the exothermic catalytic reaction channel. This configuration allows the oxidation catalyst to be backside cooled by any fluid passing through the cooling conduits. The heat of reaction is added to both the fluid in the exothermic catalytic reaction channel and the fluid passing through the cooling conduits. After discharge of the fluids from the exothermic catalytic reaction channel, the fluids mix to create a single combined flow. A further innovation in the reactor incorporates geometric changes in the exothermic catalytic reaction channel to provide streamwise variation of the velocity of the fluids in the reactor.

  20. Methodology for extracting local constants from petroleum cracking flows

    DOEpatents

    Chang, Shen-Lin; Lottes, Steven A.; Zhou, Chenn Q.

    2000-01-01

    A methodology provides for the extraction of local chemical kinetic model constants for use in a reacting flow computational fluid dynamics (CFD) computer code with chemical kinetic computations to optimize the operating conditions or design of the system, including retrofit design improvements to existing systems. The coupled CFD and kinetic computer code are used in combination with data obtained from a matrix of experimental tests to extract the kinetic constants. Local fluid dynamic effects are implicitly included in the extracted local kinetic constants for each particular application system to which the methodology is applied. The extracted local kinetic model constants work well over a fairly broad range of operating conditions for specific and complex reaction sets in specific and complex reactor systems. While disclosed in terms of use in a Fluid Catalytic Cracking (FCC) riser, the inventive methodology has application in virtually any reaction set to extract constants for any particular application and reaction set formulation. The methodology includes the step of: (1) selecting the test data sets for various conditions; (2) establishing the general trend of the parametric effect on the measured product yields; (3) calculating product yields for the selected test conditions using coupled computational fluid dynamics and chemical kinetics; (4) adjusting the local kinetic constants to match calculated product yields with experimental data; and (5) validating the determined set of local kinetic constants by comparing the calculated results with experimental data from additional test runs at different operating conditions.

  1. ''KN'' series cracking catalysts

    SciTech Connect

    Klapstov, V.F.; Khlebrikova, M.A.; Maslova, A.A.; Nefedov, B.K.

    1986-09-01

    The basic directions in improving high-activity zeolitic cracking catalysts at the present stage are improvements in the resistance to attrition and increases in the bulk density of the catalysts, along with a changeover to relatively waste-free catalyst manufacturing technology. Catalysts of the ''KN'' series have been synthesized recently with improved quality characteristics. Low-waste technology is used in manufacturing them. Data are presented which show that the KN catalysts are better than the other Soviet catalysts. The starting materials and reagents in preparing the KN catalysts are technical alumina, rare-earth element nitrates, a natural component (such as clay conforming to specification TU-21-25-146-75), sodium hydroxide, and granulated sodium silicate. The preparation of the KN catalysts is described and no silica gel is used in manufacturing the KN series catalyst, in contrast to the RSG-6Ts catalyst. The use of KN series catalysts in place of KMTsR in catalytic cracking units will result in an increase in the naphtha yield by at least 20% by weight, as well as a reduction of the catalyst consumption by a factor of 2-3. A changeover to the commerical production of this catalyst will make it possible to reduce saline waste by a factor of 8-10 and reduce the catalyst cost by a factor of 1.5-2.

  2. Crack tip deformation and fatigue crack growth

    NASA Technical Reports Server (NTRS)

    Liu, H.-W.

    1981-01-01

    Recent research on fatigue crack growth is summarized. Topics discussed include the use of the differential stress intensity factor to characterize crack tip deformation, the use of the unzipping model to study the growth of microcracks and the fatigue crack growth in a ferritic-martensitic steel, and the development of a model of fatige crack growth threshold. It is shown that in the case of small yielding, the differential stress intensity factor provides an adequate description of cyclic plastic deformation at the crack tip and correlates well with the crack growth rate. The unzipping model based on crack tip shear decohesion process is found to be in good agreement with the measured crack growth and striation spacing measurements. The proposed model of crack growth threshold gives correct predictions of the crack growth behavior in the near-threshold region.

  3. [Current research situation of H2S selective catalytic oxidation technologies and catalysts].

    PubMed

    Hao, Zheng-ping; Dou, Guang-yu; Zhang, Xin; Qu, Si-qiu

    2012-08-01

    This review summarizes and discusses different selective catalytic oxidation technologies and various catalysts for removing H2S, the undesirable byproduct of the fluid catalytic cracking (FCC) processing. Currently the selective oxidation technologies used include Superclaus, Euroclaus, Clinsulf-Do, BSR/Hi-Activity, Selectox and Modop techniques, which have various characteristics and application areas. Catalysts for H2S selective oxidation mainly contain the following systems: carbon, supported SiC, zeolite, oxide, and pillared clay. Former studies focused on carbon and oxide systems. The research interest on zeolite system decreased in recent years, while SiC is regarded as a typical support with great potential for this reaction and continues to be attractive. Pillared clay system is at the preliminary research stage, and is still far from practical application. PMID:23213923

  4. Methods of cracking a crude product to produce additional crude products

    SciTech Connect

    Mo, Weijian; Roes, Augustinus Wilhelmus Maria; Nair, Vijay

    2009-09-08

    A method for producing a crude product is disclosed. Formation fluid is produced from a subsurface in situ heat treatment process. The formation fluid is separated to produce a liquid stream and a first gas stream. The first gas stream includes olefins. The liquid stream is fractionated to produce one or more crude products. At least one of the crude products has a boiling range distribution from 38.degree. C. and 343.degree. C. as determined by ASTM Method D5307. The crude product having the boiling range distribution from 38.degree. C. and 343.degree. C. is catalytically cracked to produce one or more additional crude products. At least one of the additional crude products is a second gas stream. The second gas stream has a boiling point of at most 38.degree. C. at 0.101 MPa.

  5. Catalytic, hollow, refractory spheres

    NASA Technical Reports Server (NTRS)

    Wang, Taylor G. (Inventor); Elleman, Daniel D. (Inventor); Lee, Mark C. (Inventor); Kendall, Jr., James M. (Inventor)

    1987-01-01

    Improved, heterogeneous, refractory catalysts are in the form of gas-impervious, hollow, thin-walled spheres (10) suitable formed of a shell (12) of refractory such as alumina having a cavity (14) containing a gas at a pressure greater than atmospheric pressure. The wall material may be itself catalytic or a catalytically active material coated onto the sphere as a layer (16), suitably platinum or iron, which may be further coated with a layer (18) of activator or promoter. The density of the spheres (30) can be uniformly controlled to a preselected value within .+-.10 percent of the density of the fluid reactant such that the spheres either remain suspended or slowly fall or rise through the liquid reactant.

  6. Dynamics of cracking in drying colloidal sheets.

    PubMed

    Sengupta, Rajarshi; Tirumkudulu, Mahesh S

    2016-04-01

    Colloidal dispersions are known to display a fascinating network of cracks on drying. We probe the fracture mechanics of free-standing films of aqueous polymer-particle dispersions. Thin films of the dispersion are cast between a pair of plain steel wires and allowed to dry under ambient conditions. The strain induced on the particle network during drying is relieved by cracking. The stress which causes the films to crack has been calculated by measuring the deflection of the wires. The critical cracking stress varied inversely to the two-thirds' power of the film thickness. We also measure the velocity of the tip of a moving crack. The motion of a crack has been modeled as a competition between the release of the elastic energy stored in the particle network, the increase in surface energy as a result of the growth of a crack, the rate of viscous dissipation of the interstitial fluid and the kinetic energy associated with a moving crack. There is fair agreement between the measured crack velocities and predictions. PMID:26924546

  7. Stability of Tseokar type cracking catalyst

    SciTech Connect

    Zinov'ev, V.R.; Bryzgalina, L.V.

    1984-07-01

    This article reports on an investigation of the catalytic stability of the bead catalysts Tseokar-2 and Tseokar-4 in a catalytic cracking unit at the V.I. Lenin Groznyi Petroleum Refinery operating on a heavy distillate feed from medium-wax, low-sulfur crudes. The physical structure and the catalytic properties of the Tseokar-4 and the Tseokar-2 were determined according to the standard OST 38 01176-79. The results indicate that the yields of cracking products, the composition of the wet gas, and the properties of the liquid products (naphtha and light and heavy gasoils) were constant during over two years of testing the catalysts. It is concluded that the investigation of the Tseokar-2 and Tseokar-4 catalysts under commercial conditions without renewal over a period of 9-18 months in cracking a heavy low-sulfur feed demonstrates the high stability of the physical and catalytic properties and also the high oxidative stability of the Tseokar-4 in comparison with the Tseokar-2.

  8. Effect of support materials on supported platinum catalyst prepared using a supercritical fluid deposition technique and their catalytic performance for hydrogen-rich gas production from lignocellulosic biomass.

    PubMed

    Kaya, Burçak; Irmak, Sibel; Hesenov, Arif; Erbatur, Oktay; Erkey, Can

    2012-11-01

    A number of supported Pt catalysts have been prepared by supercritical carbon dioxide deposition technique using various supports. The reduction of Pt precursor to metal performed by heat treatment under nitrogen flow. The prepared catalysts were evaluated for gasification of wheat straw biomass hydrolysates and glucose solution for hydrogen-rich gas production. The activities of the catalysts were highly affected by distribution, amount and particle sizes of platinum on the support. In general carbon-based supported Pt catalysts exhibited better catalytic activity compared to other supports to be used. Compared to biomass hydrolysate feed, gasification of glucose always resulted in higher volume of gas mixture, however, hydrogen selectivity was decreased in all catalyst except multi-walled carbon nanotube. The deposition of Pt particles inner side of that support makes the large organic substrates inaccessible to reach and react with those metal particles. PMID:22939187

  9. Mechanics of fatigue crack closure

    NASA Technical Reports Server (NTRS)

    Newman, J. C., Jr. (Editor); Elber, Wolf (Editor)

    1988-01-01

    Papers are presented on plasticity induced crack closure, crack closure in fatigue crack growth, the dependence of crack closure on fatigue loading variables, and a procedure for standardizing crack closure levels. Also considered are a statistical approach to crack closure determination, the crack closure behavior of surface cracks under pure bending, closure measurements on short fatigue cracks, and crack closure under plane strain conditions. Other topics include fatigue crack closure behavior at high stress ratios, the use of acoustic waves for the characterization of closed fatigue cracks, and the influence of fatigue crack wake length and state of stress on crack closure.

  10. Crack, crack house sex, and HIV risk.

    PubMed

    Inciardi, J A

    1995-06-01

    Limited attention has been focused on HIV risk behaviors of crack smokers and their sex partners, yet there is evidence that the crack house and the crack-using life-style may be playing significant roles in the transmission of HIV and other sexually transmitted diseases. The purposes of this research were to study the attributes and patterns of "sex for crack" exchanges, particularly those that occurred in crack houses, and to assess their potential impact on the spread of HIV. Structured interviews were conducted with 17 men and 35 women in Miami, Florida, who were regular users of crack and who had exchanged sex for crack (or for money to buy crack) during the past 30 days. In addition, participant observation was conducted in 8 Miami crack houses. Interview and observational data suggest that individuals who exchange sex for crack do so with considerable frequency, and through a variety of sexual activities. Systematic data indicated that almost a third of the men and 89% of the women had had 100 or more sex partners during the 30-day period prior to study recruitment. Not only were sexual activities anonymous, extremely frequent, varied, uninhibited (often undertaken in public areas of crack houses), and with multiple partners but, in addition, condoms were not used during the majority of contacts. Of the 37 subjects who were tested for HIV and received their test results 31% of the men and 21% of the women were HIV seropositive. PMID:7611845

  11. Fluid-Bed Testing of Greatpoint Energy's Direct Oxygen Injection Catalytic Gasification Process for Synthetic Natural Gas and Hydrogen Coproduction Year 6 - Activity 1.14 - Development of a National Center for Hydrogen Technology

    SciTech Connect

    Swanson, Michael; Henderson, Ann

    2012-04-01

    The GreatPoint Energy (GPE) concept for producing synthetic natural gas and hydrogen from coal involves the catalytic gasification of coal and carbon. GPE’s technology “refines” coal by employing a novel catalyst to “crack” the carbon bonds and transform the coal into cleanburning methane (natural gas) and hydrogen. The GPE mild “catalytic” gasifier design and operating conditions result in reactor components that are less expensive and produce pipeline-grade methane and relatively high purity hydrogen. The system operates extremely efficiently on very low cost carbon sources such as lignites, subbituminous coals, tar sands, petcoke, and petroleum residual oil. In addition, GPE’s catalytic coal gasification process eliminates troublesome ash removal and slagging problems, reduces maintenance requirements, and increases thermal efficiency, significantly reducing the size of the air separation plant (a system that alone accounts for 20% of the capital cost of most gasification systems) in the catalytic gasification process. Energy & Environmental Research Center (EERC) pilot-scale gasification facilities were used to demonstrate how coal and catalyst are fed into a fluid-bed reactor with pressurized steam and a small amount of oxygen to “fluidize” the mixture and ensure constant contact between the catalyst and the carbon particles. In this environment, the catalyst facilitates multiple chemical reactions between the carbon and the steam on the surface of the coal. These reactions generate a mixture of predominantly methane, hydrogen, and carbon dioxide. Product gases from the process are sent to a gas-cleaning system where CO{sub 2} and other contaminants are removed. In a full-scale system, catalyst would be recovered from the bottom of the gasifier and recycled back into the fluid-bed reactor. The by-products (such as sulfur, nitrogen, and CO{sub 2}) would be captured and could be sold to the chemicals and petroleum industries, resulting in

  12. The catalytic effect of sodium and lithium ions on coupled sorption-reduction of chromate at the biotite edge-fluid interface

    SciTech Connect

    Ilton, E.S.; Moses, C.O.; Raeburn, S.P.; Veblen, D.R.

    1997-09-01

    Large single crystals of biotite and near-endmember phlogopite were reacted with aqueous solutions bearing 20 {mu}M Cr(VI) and different concentrations of NaCl, LiCl, RbCl, CsCl, NaClO{sub 4}, and Na{sub 2}SO{sub 4}. Solutions were maintained at 25 {+-} 0.5{degrees}C, 1 atm, and pH = 4.00 {+-} 0.02. Samples were extracted from the reaction chamber at 1, 3, 5, 10, and 20 h. The edges and basal planes of the reacted micas were analyzed by X-ray photoelectron spectroscopy (XPS) for major elements and Cr. XPS analyses of biotite show trivalent chromium on edge surfaces but no detectable chromium on the basal plane. XPS analyses of near-endmember phlogopites and were reacted in the same experiments as biotite showed no detectable Cr on either the basal plane or edge surfaces. Increasing Na and Li salt concentrations increased the rate of coupled sorption-reduction of chromate at the biotite edge-fluid interface, where the order of effectiveness was NaCl {approximately} NaClO{sub 4} > LiCl. In contrast, no Cr was detected on mica edges after reaction in RbCl and CsCl solutions. Comparison of equimolar NaCl and LiCl experiments indicate that the active agent is Na and Li, not ionic strength or the anion. Sulfate tends to block the reaction more so than chloride. We conclude that it is the substitution of hydrated cations for interlayer K in biotite that enhances the heterogeneous reduction of chromate at the biotite edge-fluid interface. 52 refs., 17 figs., 5 tabs.

  13. Gear Crack Propagation Investigation

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Reduced weight is a major design goal in aircraft power transmissions. Some gear designs incorporate thin rims to help meet this goal. Thin rims, however, may lead to bending fatigue cracks. These cracks may propagate through a gear tooth or into the gear rim. A crack that propagates through a tooth would probably not be catastrophic, and ample warning of a failure could be possible. On the other hand, a crack that propagates through the rim would be catastrophic. Such cracks could lead to disengagement of a rotor or propeller from an engine, loss of an aircraft, and fatalities. To help create and validate tools for the gear designer, the NASA Lewis Research Center performed in-house analytical and experimental studies to investigate the effect of rim thickness on gear-tooth crack propagation. Our goal was to determine whether cracks grew through gear teeth (benign failure mode) or through gear rims (catastrophic failure mode) for various rim thicknesses. In addition, we investigated the effect of rim thickness on crack propagation life. A finite-element-based computer program simulated gear-tooth crack propagation. The analysis used principles of linear elastic fracture mechanics, and quarter-point, triangular elements were used at the crack tip to represent the stress singularity. The program had an automated crack propagation option in which cracks were grown numerically via an automated remeshing scheme. Crack-tip stress-intensity factors were estimated to determine crack-propagation direction. Also, various fatigue crack growth models were used to estimate crack-propagation life. Experiments were performed in Lewis' Spur Gear Fatigue Rig to validate predicted crack propagation results. Gears with various backup ratios were tested to validate crack-path predictions. Also, test gears were installed with special crack-propagation gages in the tooth fillet region to measure bending-fatigue crack growth. From both predictions and tests, gears with backup ratios

  14. Crack spectra analysis

    SciTech Connect

    Tiernan, M.

    1980-09-01

    Crack spectra derived from velocity data have been shown to exhibit systematics which reflect microstructural and textural differences between samples (Warren and Tiernan, 1980). Further research into both properties and information content of crack spectra have yielded the following: Spectral features are reproducible even at low pressures; certain observed spectral features may correspond to non-in-situ crack populations created during sample retrieval; the functional form of a crack spectra may be diagnostic of the sample's grain texture; hysteresis is observed in crack spectra between up and down pressure runs - it may be due to friction between the faces of closed crack populations.

  15. Gear crack propagation investigations

    NASA Technical Reports Server (NTRS)

    Lewicki, David G.; Ballarini, Roberto

    1996-01-01

    Analytical and experimental studies were performed to investigate the effect of gear rim thickness on crack propagation life. The FRANC (FRacture ANalysis Code) computer program was used to simulate crack propagation. The FRANC program used principles of linear elastic fracture mechanics, finite element modeling, and a unique re-meshing scheme to determine crack tip stress distributions, estimate stress intensity factors, and model crack propagation. Various fatigue crack growth models were used to estimate crack propagation life based on the calculated stress intensity factors. Experimental tests were performed in a gear fatigue rig to validate predicted crack propagation results. Test gears were installed with special crack propagation gages in the tooth fillet region to measure bending fatigue crack growth. Good correlation between predicted and measured crack growth was achieved when the fatigue crack closure concept was introduced into the analysis. As the gear rim thickness decreased, the compressive cyclic stress in the gear tooth fillet region increased. This retarded crack growth and increased the number of crack propagation cycles to failure.

  16. Cocaine (Coke, Crack) Facts

    MedlinePlus

    ... That People Abuse » Cocaine (Coke, Crack) Facts Cocaine (Coke, Crack) Facts Listen Cocaine is a white ... Version Download "My life was built around getting cocaine and getting high." Stacey is recovering from her ...

  17. Crack propagation in graphene

    NASA Astrophysics Data System (ADS)

    Budarapu, P. R.; Javvaji, B.; Sutrakar, V. K.; Roy Mahapatra, D.; Zi, G.; Rabczuk, T.

    2015-08-01

    The crack initiation and growth mechanisms in an 2D graphene lattice structure are studied based on molecular dynamics simulations. Crack growth in an initial edge crack model in the arm-chair and the zig-zag lattice configurations of graphene are considered. Influence of the time steps on the post yielding behaviour of graphene is studied. Based on the results, a time step of 0.1 fs is recommended for consistent and accurate simulation of crack propagation. Effect of temperature on the crack propagation in graphene is also studied, considering adiabatic and isothermal conditions. Total energy and stress fields are analyzed. A systematic study of the bond stretching and bond reorientation phenomena is performed, which shows that the crack propagates after significant bond elongation and rotation in graphene. Variation of the crack speed with the change in crack length is estimated.

  18. Short crack growth behavior

    SciTech Connect

    Sadananda, K.; Vasudevan, A.K.

    1997-12-01

    The authors have re-evaluated short crack growth behavior using concepts developed recently, and they show that these concepts provide a unified framework that can explain both short and long crack growth behavior without resorting to the crack closure effect. They consider that the behavior of long cracks, including the effects of load ratio, R, is fundamental. they had shown previously that, since fatigue is at least a two-parameter problem in that at least two load parameters are required for an unambiguous description, there are two critical driving forces required simultaneously for fatigue cracks to grow. In extending this analysis to the growth of short cracks, they reject the current notion of the lack of similitude for short cracks and express the similitude as a fundamental postulate that, for a given crack growth mechanism, equal crack tip driving forces result in equal crack growth rates. Short crack growth behavior confirms the concept that two parameters are required to define fatigue; consequently, for fatigue cracks to grow, two thresholds need to be satisfied simultaneously. The authors present examples from the literature to illustrate the concepts discussed.

  19. White-Etching Matter in Bearing Steel. Part I: Controlled Cracking of 52100 Steel

    NASA Astrophysics Data System (ADS)

    Solano-Alvarez, W.; Bhadeshia, H. K. D. H.

    2014-10-01

    Although most of the research performed in bearing steel metallurgy aims to prevent crack nucleation and propagation, some applications require the exact opposite in order to study the role that disconnected surfaces inside the bulk material play when load is applied, or when fluids entrapped in surface cracks propagate tensile stresses or exacerbate corrosion. Four heat treatments have been designed to create controlled arrays of crack types and distributions in quenched and untempered steel normally used in the manufacture of bearings. The varieties of cracks studied include sparsely distributed martensite-plate cracks, fine-grain-boundary cracks, abundant martensite-plate cracks, and surface cracks. The intention was to create samples which can then be subjected to appropriate mechanical testing so that phenomena such as the appearance of "white-etching areas" or "white-etching cracks," crack-lubricant interactions, or hydrogen trapping can be studied further.

  20. Bed-limited cracks in effective medium theory

    NASA Astrophysics Data System (ADS)

    Tod, S. R.

    2003-02-01

    An effective medium theory typically requires the description of a mean crack shape. In general, for simplicity, this is taken to be a flat, circular (`penny-shaped') crack. However, this places an unnecessary limitation on the theory, when it is perhaps more realistic to describe a crack in terms of having a bounded width and an otherwise ellipsoidal shape. The generalization of the method of smoothing, as proposed by Hudson (1994, Geophys. J. Int.,117, 555-561) , to extend his original model (Hudson, 1980. Math. proc. Camb. phil. Soc.,88, 371-384), has been used to study the role of the crack width and the ratio of the two larger dimensions in determining the properties of the effective medium. In general, this leads to a description of the medium as having orthorhombic symmetry, and provides a suitable description of a material where the crack dimensions are restricted in one direction owing to, for example, bed-limiting effects, while remaining unconfined in other directions. An elliptical flat crack limit is determined, analoguous to the circular crack description of the original Hudson model. In addition to the isolated crack description, the theory is extended to include the fluid flow mechanism of Tod (2001, Geophys. J. Int.,146, 249-263) that models the flow as being dominated by crack-to-crack flow and is valid for low matrix porosities and over a large range of frequencies, provided that the wavelength is much greater than the crack dimensions.

  1. The Effect of Water on Crack Interaction

    NASA Astrophysics Data System (ADS)

    Gaede, O.; Regenauer-Lieb, K.

    2009-04-01

    While the mechanical coupling between pore fluid and solid phase is relatively well understood, quantitative studies dealing with chemical-mechanical weakening in geological materials are rare. Many classical poroelastic problems can be addressed with the simple law of effective stress. Experimental studies show that the presence of a chemically active fluid can have effects that exceed the predictions of the law of effective stress. These chemical fluid-rock interactions alter the mechanical properties of the solid phase. Especially chemical-mechanical weakening has important ramifications for many areas of applied geosciences ranging from nuclear waste disposal over reservoir enhancement to fault stability. In this study, we model chemically induced changes of the size of the process zone around a crack tip. The knowledge of the process zone size is used to extend existing effective medium approximations of cracked solids. The stress distribution around a crack leads to a chemical potential gradient. This gradient will be a driver for mass diffusion through the solid phase. As an example, mass diffusion is towards the crack tip for a mode I crack. In this case a chemical reaction, that weakens the solid phase, will increase the size of the process zone around the crack tip. We apply our model to the prominent hydrolytic weakening effect observed in the quartz-water system (Griggs and Blacic, 1965). Hydrolytic weakening is generally attributed to water hydrolyzing the strong Si-O bonds of the quartz crystal. The hydrolysis replaces a Si-O-Si bridge with a relatively weak hydrogen bridge between two silanol groups. This enhances dislocation mobility and hence the yield stress is reduced. The plastic process zone around a crack tip is therefore larger in a wet crystal than in a dry crystal. We calculate the size of the process zone by solving this coupled mechanical-chemical problem with the Finite Element code ABAQUS. We consider single crack, collinear crack and

  2. Supplemental cracked corn or wheat bran for steers grazing endophyte-free fescue pasture: effects on live weight gain, nutrient quality, forage intake, particulate and fluid kinetics, ruminal fermentation, and digestion.

    PubMed

    Hess, B W; Krysl, L J; Judkins, M B; Holcombe, D W; Hess, J D; Hanks, D R; Huber, S A

    1996-05-01

    Two experiments were conducted with beef steers (Exp. 1, average BW of 580 kg; Exp. 2, average BW of 247 kg) to evaluate the use of no supplements (CON) or daily supplementation with (OM basis) .34% of BW of cracked corn (CORN), .34% of BW of wheat bran (WBBW), or .48% of BW of wheat bran (WBISO; calculated to be isocaloric to CORN) on digestive responses (Exp. 1) and live weight gain (Exp. 2). In Exp. 1, type of supplement did not affect (P > .10) the dietary fiber or N constituents, but in vitro OM disappearance of the forage differed (P < .10) with supplementation and type of supplement fed. Supplemented steers consumed less (P < .05) forage and total OM. Particulate passage, fluid passage, and ruminal pH were not affected (P > .10) by supplementation. Ruminal NH3 N concentration showed (P < .05) a treatment x sampling time interaction and, in general, WBBW and WBISO steers had greater ruminal NH3 N than CORN and CON steers. Total VFA concentrations and molar proportions of propionate were lower (P < .10) in CON steers than in supplemented steers; no differences were noted (P > .10) among supplemented steers. Molar proportions of acetate were lower (P = .01) in supplemented steers than in CON steers and were greater (P = .03) in WBBW steers than in WBISO steers. Butyrate molar proportions were lower (P < .05) in CON steers than in supplemented steers and differed (P < .10) with type and quantity of supplement supplied. In situ forage NDF disappearance at 6, 9, and 24 h after feeding and rate of disappearance were greater (P < .05) in CON steers than in supplemented steers. In Exp. 2, CON steers weighed less (P = .01) than supplemented steers, CORN steers weighed more (P = .08) than wheat bran-supplemented steers, and WBISO steers weighed more (P = .02) than WBBW steers; ADG for 90 d followed a similar response. Results suggest that supplementation of wheat bran rather than corn did not seem to stop the reduction in forage intake or OM digestion associated with

  3. Piloted rich-catalytic lean-burn hybrid combustor

    DOEpatents

    Newburry, Donald Maurice

    2002-01-01

    A catalytic combustor assembly which includes, an air source, a fuel delivery means, a catalytic reactor assembly, a mixing chamber, and a means for igniting a fuel/air mixture. The catalytic reactor assembly is in fluid communication with the air source and fuel delivery means and has a fuel/air plenum which is coated with a catalytic material. The fuel/air plenum has cooling air conduits passing therethrough which have an upstream end. The upstream end of the cooling conduits is in fluid communication with the air source but not the fuel delivery means.

  4. Bifunctional catalytic electrode

    NASA Technical Reports Server (NTRS)

    Cisar, Alan (Inventor); Murphy, Oliver J. (Inventor); Clarke, Eric (Inventor)

    2005-01-01

    The present invention relates to an oxygen electrode for a unitized regenerative hydrogen-oxygen fuel cell and the unitized regenerative fuel cell having the oxygen electrode. The oxygen electrode contains components electrocatalytically active for the evolution of oxygen from water and the reduction of oxygen to water, and has a structure that supports the flow of both water and gases between the catalytically active surface and a flow field or electrode chamber for bulk flow of the fluids. The electrode has an electrocatalyst layer and a diffusion backing layer interspersed with hydrophilic and hydrophobic regions. The diffusion backing layer consists of a metal core having gas diffusion structures bonded to the metal core.

  5. Catalytic hollow spheres

    NASA Technical Reports Server (NTRS)

    Wang, Taylor G. (Inventor); Elleman, Daniel D. (Inventor); Lee, Mark C. (Inventor); Kendall, Jr., James M. (Inventor)

    1986-01-01

    The improved, heterogeneous catalysts are in the form of gas-impervious, hollow, thin-walled spheres (10) suitably formed of a shell (12) of metal such as aluminum having a cavity (14) containing a gas at a pressure greater than atmospheric pressure. The wall material may be, itself, catalytic or the catalyst can be coated onto the sphere as a layer (16), suitably platinum or iron, which may be further coated with a layer (18) of activator or promoter. The density of the spheres (30) can be uniformly controlled to a preselected value within .+-.10 percent of the density of the fluid reactant such that the spheres either remain suspended or slowly fall or rise through the liquid reactant.

  6. Catalytic hollow spheres

    NASA Technical Reports Server (NTRS)

    Wang, Taylor G. (Inventor); Elleman, Daniel D. (Inventor); Lee, Mark C. (Inventor); Kendall, Jr., James M. (Inventor)

    1989-01-01

    The improved, heterogeneous catalysts are in the form of gas-impervious, hollow, thin-walled spheres (10) suitably formed of a shell (12) of metal such as aluminum having a cavity (14) containing a gas at a pressure greater than atmospheric pressure. The wall material may be, itself, catalytic or the catalyst can be coated onto the sphere as a layer (16), suitably platinum or iron, which may be further coated with a layer (18) of activator or promoter. The density of the spheres (30) can be uniformly controlled to a preselected value within .+-.10 percent of the density of the fluid reactant such that the spheres either remain suspended or slowly fall or rise through the liquid reactant.

  7. Investigation of Helicopter Longeron Cracks

    NASA Technical Reports Server (NTRS)

    Newman, John A.; Baughman, James; Wallace, Terryl A.

    2009-01-01

    Four cracked longerons, containing a total of eight cracks, were provided for study. Cracked regions were cut from the longerons. Load was applied to open the cracks, enabling crack surface examination. Examination revealed that crack propagation was driven by fatigue loading in all eight cases. Fatigue crack initiation appears to have occurred on the top edge of the longerons near geometric changes that affect component bending stiffness. Additionally, metallurgical analysis has revealed a local depletion in alloying elements in the crack initiation regions that may be a contributing factor. Fatigue crack propagation appeared to be initially driven by opening-mode loading, but at a crack length of approximately 0.5 inches (12.7 mm), there is evidence of mixed-mode crack loading. For the longest cracks studied, shear-mode displacements destroyed crack-surface features of interest over significant portions of the crack surfaces.

  8. Multiple Cracks Propagate Simultaneously in Polymer Liquids in Tension.

    PubMed

    Huang, Qian; Alvarez, Nicolas J; Shabbir, Aamir; Hassager, Ole

    2016-08-19

    Understanding the mechanism of fracture is essential for material and process design. While the initiation of fracture in brittle solids is generally associated with the preexistence of material imperfections, the mechanism for initiation of fracture in viscoelastic fluids, e.g., polymer melts and solutions, remains an open question. We use high speed imaging to visualize crack propagation in entangled polymer liquid filaments under tension. The images reveal the simultaneous propagation of multiple cracks. The critical stress and strain for the onset of crack propagation are found to be highly reproducible functions of the stretch rate, while the position of initiation is completely random. The reproducibility of conditions for fracture points to a mechanism for crack initiation that depends on the dynamic state of the material alone, while the crack profiles reveal the mechanism of energy dissipation during crack propagation. PMID:27588883

  9. Elevated temperature crack growth

    NASA Technical Reports Server (NTRS)

    Kim, K. S.; Vanstone, R. H.

    1992-01-01

    The purpose of this program was to extend the work performed in the base program (CR 182247) into the regime of time-dependent crack growth under isothermal and thermal mechanical fatigue (TMF) loading, where creep deformation also influences the crack growth behavior. The investigation was performed in a two-year, six-task, combined experimental and analytical program. The path-independent integrals for application to time-dependent crack growth were critically reviewed. The crack growth was simulated using a finite element method. The path-independent integrals were computed from the results of finite-element analyses. The ability of these integrals to correlate experimental crack growth data were evaluated under various loading and temperature conditions. The results indicate that some of these integrals are viable parameters for crack growth prediction at elevated temperatures.

  10. CRACK MODELLING FOR RADIOGRAPHY

    SciTech Connect

    Chady, T.; Napierala, L.

    2010-02-22

    In this paper, possibility of creation of three-dimensional crack models, both random type and based on real-life radiographic images is discussed. Method for storing cracks in a number of two-dimensional matrices, as well algorithm for their reconstruction into three-dimensional objects is presented. Also the possibility of using iterative algorithm for matching simulated images of cracks to real-life radiographic images is discussed.

  11. Thermal cracking of butadiene

    SciTech Connect

    Duisters, H.A.M. )

    1994-01-01

    This paper presents experimental data on the thermal cracking of butadiene in a pilot plant, under conditions representative of industrial operation. The product distribution of pure-butadiene cracking is shown. Results from cocracking experiments in naphtha and C[sub 4]-raffinate are also presented. It is shown that butadiene cracking can be an interesting outlet for the increasing butadiene overcapacity in steam crackers. Some aspects of coke formation during butadiene pyrolysis are addressed as well.

  12. Crack Modelling for Radiography

    NASA Astrophysics Data System (ADS)

    Chady, T.; Napierała, L.

    2010-02-01

    In this paper, possibility of creation of three-dimensional crack models, both random type and based on real-life radiographic images is discussed. Method for storing cracks in a number of two-dimensional matrices, as well algorithm for their reconstruction into three-dimensional objects is presented. Also the possibility of using iterative algorithm for matching simulated images of cracks to real-life radiographic images is discussed.

  13. Raney nickel catalytic device

    DOEpatents

    O'Hare, Stephen A.

    1978-01-01

    A catalytic device for use in a conventional coal gasification process which includes a tubular substrate having secured to its inside surface by expansion a catalytic material. The catalytic device is made by inserting a tubular catalytic element, such as a tubular element of a nickel-aluminum alloy, into a tubular substrate and heat-treating the resulting composite to cause the tubular catalytic element to irreversibly expand against the inside surface of the substrate.

  14. Automatic crack propagation tracking

    NASA Technical Reports Server (NTRS)

    Shephard, M. S.; Weidner, T. J.; Yehia, N. A. B.; Burd, G. S.

    1985-01-01

    A finite element based approach to fully automatic crack propagation tracking is presented. The procedure presented combines fully automatic mesh generation with linear fracture mechanics techniques in a geometrically based finite element code capable of automatically tracking cracks in two-dimensional domains. The automatic mesh generator employs the modified-quadtree technique. Crack propagation increment and direction are predicted using a modified maximum dilatational strain energy density criterion employing the numerical results obtained by meshes of quadratic displacement and singular crack tip finite elements. Example problems are included to demonstrate the procedure.

  15. Fluid imbalance

    MedlinePlus

    ... up in the body. This is called fluid overload (volume overload). This can lead to edema (excess fluid in ... Water imbalance; Fluid imbalance - dehydration; Fluid buildup; Fluid overload; Volume overload; Loss of fluids; Edema - fluid imbalance; ...

  16. Crack layer theory

    NASA Technical Reports Server (NTRS)

    Chudnovsky, A.

    1987-01-01

    A damage parameter is introduced in addition to conventional parameters of continuum mechanics and consider a crack surrounded by an array of microdefects within the continuum mechanics framework. A system consisting of the main crack and surrounding damage is called crack layer (CL). Crack layer propagation is an irreversible process. The general framework of the thermodynamics of irreversible processes are employed to identify the driving forces (causes) and to derive the constitutive equation of CL propagation, that is, the relationship between the rates of the crack growth and damage dissemination from one side and the conjugated thermodynamic forces from another. The proposed law of CL propagation is in good agreement with the experimental data on fatigue CL propagation in various materials. The theory also elaborates material toughness characterization.

  17. Crack layer theory

    NASA Technical Reports Server (NTRS)

    Chudnovsky, A.

    1984-01-01

    A damage parameter is introduced in addition to conventional parameters of continuum mechanics and consider a crack surrounded by an array of microdefects within the continuum mechanics framework. A system consisting of the main crack and surrounding damage is called crack layer (CL). Crack layer propagation is an irreversible process. The general framework of the thermodynamics of irreversible processes are employed to identify the driving forces (causes) and to derive the constitutive equation of CL propagation, that is, the relationship between the rates of the crack growth and damage dissemination from one side and the conjugated thermodynamic forces from another. The proposed law of CL propagation is in good agreement with the experimental data on fatigue CL propagation in various materials. The theory also elaborates material toughness characterization.

  18. Small-crack test methods

    NASA Astrophysics Data System (ADS)

    Larsen, James M.; Allison, John E.

    This book contains chapters on fracture mechanics parameters for small fatigue cracks, monitoring small-crack growth by the replication method, measurement of small cracks by photomicroscopy (experiments and analysis), and experimental mechanics of microcracks. Other topics discussed are the real-time measurement of small-crack-opening behavior using an interferometric strain/displacement gage; direct current electrical potential measurement of the growth of small cracks; an ultrasonic method for the measurement of the size and opening behavior of small fatigue cracks; and the simulation of short crack and other low closure loading conditions, utilizing constant K(max) Delta-K-decreasing fatigue crack growth procedures.

  19. Effect of crack surface geometry on fatigue crack closure

    SciTech Connect

    Drury, W.J.; Gokhale, A.M.; Antolovich, S.D.

    1995-10-01

    The geometry of crack faces often plays a critical role in reducing crack extension forces when crack closure occurs during fatigue crack growth. Most previous studies of fatigue crack closure are concerned with mechanical measure of closure as related to the crack growth rate; very little attention has been given to the geometry of the crack surfaces. The objective is to identify those aspects of crack surface geometry that are important in the closure process, to develop quantitative fractographic techniques to estimate such attributes in a statistically significant and robust manner, and to correlate them to the physical process of crack closure. For this purpose, fatigue crack propagation experiments were performed on a Ni-base superalloy and crack growth rates and crack closure loads were measured. Digital image profilometry and software-based analysis techniques were used for statistically reliable and detailed quantitative characterization of fatigue crack profiles. It is shown that the dimensionless, scale-independent attributes, such a height-to-width ratio of asperities, fractal dimensions, dimensionless roughness parameters, etc., do not represent the aspects of crack geometry that are of primary importance in the crack closure phenomena. Furthermore, it is shown that the scale-dependent characteristics, such as average asperity height, do represent the aspects of crack geometry that play an interactive role in the closure process. These observations have implications concerning the validity of geometry-dependent, closure-based models for fatigue crack growth.

  20. Effect of crack surface geometry on fatigue crack closure

    NASA Astrophysics Data System (ADS)

    Drury, W. J.; Gokhale, Arun M.; Antolovich, S. D.

    1995-10-01

    The geometry of crack faces often plays a critical role in reducing crack extension forces when crack closure occurs during fatigue crack growth. Most previous studies of fatigue crack closure are concerned with mechanical measures of closure as related to the crack growth rate; very little attention has been given to the geometry of the crack surfaces. Our objective is to identify those aspects of crack surface geometry that are important in the closure process, to develop quantitative fractographic techniques to estimate such attributes in a statistically significant and robust manner, and to correlate them to the physical process of crack closure. For this purpose, fatigue crack propagation experiments were performed on a Ni-base superalloy and crack growth rates and crack closure loads were measured. Digital image profilometry and software-based analysis techniques were used for statistically reliable and detailed quantitative characterization of fatigue crack profiles. It is shown that the dimensionless, scale-independent attributes, such as height-to-width ratio of asperities, fractal dimensions, dimensionless roughness parameters, etc., do not represent the aspects of crack geometry that are of primary importance in the crack closure phenomena. Furthermore, it is shown that the scaledependent characteristics, such as average asperity height, do represent the aspects of crack geometry that play an interactive role in the closure process. These observations have implications concerning the validity of geometry-dependent, closure-based models for fatigue crack growth.

  1. Development of crack shape: LBB methodology for cracked pipes

    SciTech Connect

    Moulin, D.; Chapuliot, S.; Drubay, B.

    1997-04-01

    For structures like vessels or pipes containing a fluid, the Leak-Before-Break (LBB) assessment requires to demonstrate that it is possible, during the lifetime of the component, to detect a rate of leakage due to a possible defect, the growth of which would result in a leak before-break of the component. This LBB assessment could be an important contribution to the overall structural integrity argument for many components. The aim of this paper is to review some practices used for LBB assessment and to describe how some new R & D results have been used to provide a simplified approach of fracture mechanics analysis and especially the evaluation of crack shape and size during the lifetime of the component.

  2. Cracking blends of gas oil and residual oil

    SciTech Connect

    Myers, G.D.

    1988-03-01

    In a catalytic cracking process unit wherein a gas oil feed is cracked in a cracking zone at an elevated temperature in the presence of a cracking catalyst, the cracking catalyst is regenerated in a regeneration zone by burning coke of the catalyst, and catalyst is circulated between the cracking zone and the regeneration zone. The improvement is described for obtaining a naphtha product of improved octane number comprising introducing sufficient of a nickel and vanadium metals-containing heavy feedstock with the gas oil feed introduced into the cracking zone to deposit nickel and vanadium metals on the catalyst and raise the nickel and metals-content of the catalyst to a level ranging from about 1500 to about 6000 parts per million of the metals expressed as equivalent nickel, based on the weight of the catalyst, and maintaining the nickel and vanadium metals level on the catalyst by withdrawing high nickel and vanadium metals containing catalyst and adding low nickel and vanadium metals-containing catalyst to the regeneration zone.

  3. Modelling of hydride cracking

    SciTech Connect

    Zheng, X.J.; Metzger, D.R.; Glinka, G.; Dubey, R.N.

    1996-12-01

    Zirconium alloys may be susceptible to hydride formation under certain service conditions, due to hydrogen diffusion and precipitation in the presence of stress concentrations and temperature gradients. The inhomogeneous brittle hydride platelets that form are modeled as plane defects of zero thickness, with fracture toughness less than that of the matrix. A fracture criterion based on sufficient energy and stress is proposed for either delayed hydride cracking (DHC) under constant loading conditions, or hydride cracking at rising loads, such as in a fracture toughness test. The fracture criterion is validated against available experimental data concerning initiation of hydride fracture in smooth specimens, and DHC in cracked specimens under various loading and temperature conditions.

  4. Surface Enhancement Improves Crack Resistance

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The low plasticity burnishing (LPB) process produces a deep layer of surface compression in a quick and affordable manner to produce metal surfaces free of scratches, nicks, and gouges. The process, designed for easy inclusion in the manufacturing environment, can be performed with conventional Computer Numerical Control machine tools. This allows parts to be processed during manufacturing, rather than as a post process in a separate facility. A smooth, free-rolling spherical ball suspended in a fluid allows for single-point contact. The ball comes into mechanical contact only with the surface to be burnished, and can be moved in any direction. LPB can be applied to all types of carbon and alloy steel, stainless steel, cast iron, aluminum, titanium, and nickel- based super alloys. In addition to improving a surface's resistance to fatigue and damage, treatment stops the growth of shallow cracks. The LPB process is used on the leading edges of turbine blades to improve resistance to foreign object damage and crack growth. This means significant savings for aircraft owners, since maintenance requirements to inspect for fatigue damage, replace parts, and remove corrosion damage increase the cost of operation.

  5. Quantity Effect of Radial Cracks on the Cracking Propagation Behavior and the Crack Morphology

    PubMed Central

    Chen, Jingjing; Xu, Jun; Liu, Bohan; Yao, Xuefeng; Li, Yibing

    2014-01-01

    In this letter, the quantity effect of radial cracks on the cracking propagation behavior as well as the circular crack generation on the impacted glass plate within the sandwiched glass sheets are experimentally investigated via high-speed photography system. Results show that the radial crack velocity on the backing glass layer decreases with the crack number under the same impact conditions during large quantities of repeated experiments. Thus, the “energy conversion factor” is suggested to elucidate the physical relation between the cracking number and the crack propagation speed. Besides, the number of radial crack also takes the determinative effect in the crack morphology of the impacted glass plate. This study may shed lights on understanding the cracking and propagation mechanism in laminated glass structures and provide useful tool to explore the impact information on the cracking debris. PMID:25048684

  6. Multiple artificial geothermal cracks in a hot dry rock mass for extraction of heat

    SciTech Connect

    Shibuya, Y.; Abe, H.; Sekine, H.; Takahashi, Y.

    1985-06-01

    Theoretical analysis is made for multiple geothermal cracks. A periodic array of two-dimensional cracks is considered as a model of the multiple geothermal cracks, and is analyzed on the basis of the two-dimensional theory of quasi-static thermoelasticity. The singular integral equations are derived from the boundary conditions, and they are solved by applying the combination of inversion formula and collocation method. Numerical results for the fluid temperature at an outlet, the rock mass temperature, the shape of the geothermal cracks and the stress distribution around the geothermal cracks are shown in graphs.

  7. Poroelastic Relaxation in Thermally Cracked Aggregates of Sintered Glass Beads

    NASA Astrophysics Data System (ADS)

    Li, Y.; Olin, M.; Clark, A.; Jackson, I.; Schmitt, D. R.

    2012-12-01

    Synthetic analogues for cracked crustal rocks have been prepared by sintering soda-lime-silica glass beads of ~ 300 micron diameter at temperatures near the glass transition, and subsequent thermal cracking induced by quenching from high temperature into water. The resulting microstructure involves a controllable concentration (0.03-0.15) of equant pores connected by a network of cracks of uniformly low aspect ratio α ~ 0.0007. Systematic studies of seismic wave speeds and attenuation in such media saturated with fluids ranging widely in viscosity, with both high-frequency ultrasonic and low-frequency forced-oscillation techniques, and related measurements of permeability, are expected to provide a more robust laboratory-based understanding of poroelastic relaxation. In the first stage of this project, cylindrical specimens of 15 mm diameter and 50-150 mm length were tested in both torsional and flexural oscillation. Such measurements were performed under conditions of independently controlled confining (Pc) and pore-fluid (Pf) pressures. Permeability was measured in situ by isolating the pore fluid reservoirs at either end of the specimen and observing the return to pore-pressure equilibrium following a small pore-pressure perturbation in one of the reservoirs. The same specimens were tested dry and argon-saturated, before and after thermal cracking, in order to isolate the effect of the crack network. The responses to torsional and flexural oscillation are essentially elastic with both shear modulus and Young's modulus E independent of oscillation period (1-100 s) and minimal strain-energy dissipation 1/Q < 0.002. The permeability and elastic moduli of the cracked material are each markedly pressure dependent for effective pressure Peff = Pc - Pf < 50 MPa - consistent with crack closure at pressures ~ Eα. Work in progress with fluid saturants of higher viscosity (water and glycerol) is targeting predicted porelastic transitions associated with local (squirt

  8. Switchable catalytic DNA catenanes.

    PubMed

    Hu, Lianzhe; Lu, Chun-Hua; Willner, Itamar

    2015-03-11

    Two-ring interlocked DNA catenanes are synthesized and characterized. The supramolecular catenanes show switchable cyclic catalytic properties. In one system, the catenane structure is switched between a hemin/G-quadruplex catalytic structure and a catalytically inactive state. In the second catenane structure the catenane is switched between a catalytically active Mg(2+)-dependent DNAzyme-containing catenane and an inactive catenane state. In the third system, the interlocked catenane structure is switched between two distinct catalytic structures that include the Mg(2+)- and the Zn(2+)-dependent DNAzymes. PMID:25642796

  9. Ethylene by Naphta Cracking

    ERIC Educational Resources Information Center

    Wiseman, Peter

    1977-01-01

    Presents a discussion of the manufacture of ethylene by thermal cracking of hydrocarbon feedstocks that is useful for introducing the subject of industrial chemistry into a chemistry curriculum. (MLH)

  10. Elevated temperature crack growth

    NASA Technical Reports Server (NTRS)

    Kim, K. S.; Vanstone, R. H.; Malik, S. N.; Laflen, J. H.

    1988-01-01

    A study was performed to examine the applicability of path-independent (P-I) integrals to crack growth problems in hot section components of gas turbine aircraft engines. Alloy 718 was used and the experimental parameters included combined temperature and strain cycling, thermal gradients, elastic-plastic strain levels, and mean strains. A literature review was conducted of proposed P-I integrals, and those capable of analyzing hot section component problems were selected and programmed into the postprocessor of a finite element code. Detailed elastic-plastic finite element analyses were conducted to simulate crack growth and crack closure of the test specimen, and to evaluate the P-I integrals. It was shown that the selected P-I integrals are very effective for predicting crack growth for isothermal conditions.

  11. Thermal cracking of hydrocarbons

    SciTech Connect

    Braun, R.L.; Burnham, A.K.

    1988-09-01

    Knowledge of thermal cracking of hydrocarbons is important in understanding and modeling petroleum maturation. We have reviewed the literature on the thermal cracking of pure hydrocarbons and mixtures of hydrocarbons, with particular attention given to dependence of the kinetics on temperature, pressure, and phase. Major uncertainties remain with regard to pressure dependence. Based on this review, we developed a simple, four-component, three-reaction model for oil-cracking. We also developed a simple, kerogen-maturation, kinetic model that incorporates hydrogen and carbon balance and includes the most important oil- and gas-forming reactions: kerogen pyrolysis, three oil-cracking reactions, and three coke-pyrolysis reactions. Tentative stoichiometry parameters are given for lacustrine and marine kerogens. 35 refs., 5 figs., 5 tabs.

  12. Elevated Temperature Crack Propagation

    NASA Technical Reports Server (NTRS)

    Orange, Thomas W.

    1994-01-01

    This paper is a summary of two NASA contracts on high temperature fatigue crack propagation in metals. The first evaluated the ability of fairly simple nonlinear fracture parameters to correlate crack propagation. Hastelloy-X specimens were tested under isothermal and thermomechanical cycling at temperatures up to 980 degrees C (1800 degrees F). The most successful correlating parameter was the crack tip opening displacement derived from the J-integral. The second evaluated the ability of several path-independent integrals to correlate crack propagation behavior. Inconel 718 specimens were tested under isothermal, thermomechanical, temperature gradient, and creep conditions at temperatures up to 650 degrees C (1200 degrees F). The integrals formulated by Blackburn and by Kishimoto correlated the data reasonably well under all test conditions.

  13. Crack-growth analysis

    NASA Technical Reports Server (NTRS)

    Bianca, C.; Creager, M.

    1976-01-01

    Flexible, adaptable, integrative routine, computer program incorporates Collipriest-Ehret and Paris-Forman equations. Calculates growth from initial defect size and terminates calculation when crack is sufficiently large for critical condition. Wheeler, Willenborg, and Grumman Closure models are available.

  14. The kinked interface crack

    NASA Astrophysics Data System (ADS)

    Heitzer, Joerg

    1992-05-01

    Two methods for the numerical solution of the integral equation describing the kinked interface crack, one proposed by Erdogan et al. (1973) and the other by Theokaris and Iokimidis (1979), are examined. The method of Erdogan et al. is then used to solve the equation in order to determine the kinking angle of the interface crack. Results are presented for two material combinations, aluminum/epoxy and glass/ceramic, under uniaxial tension in the direction normal to the interface.

  15. Catalytic pyrolysis of waste rice husk over mesoporous materials

    PubMed Central

    2012-01-01

    Catalytic fast pyrolysis of waste rice husk was carried out using pyrolysis-gas chromatography/mass spectrometry [Py-GC/MS]. Meso-MFI zeolite [Meso-MFI] was used as the catalyst. In addition, a 0.5-wt.% platinum [Pt] was ion-exchanged into Meso-MFI to examine the effect of Pt addition. Using a catalytic upgrading method, the activities of the catalysts were evaluated in terms of product composition and deoxygenation. The structure and acid site characteristics of the catalysts were analyzed by Brunauer-Emmett-Teller surface area measurement and NH3 temperature-programmed desorption analysis. Catalytic upgrading reduced the amount of oxygenates in the product vapor due to the cracking reaction of the catalysts. Levoglucosan, a polymeric oxygenate species, was completely decomposed without being detected. While the amount of heavy phenols was reduced by catalytic upgrading, the amount of light phenols was increased because of the catalytic cracking of heavy phenols into light phenols and aromatics. The amount of aromatics increased remarkably as a result of catalytic upgrading, which is attributed to the strong Brönsted acid sites and the shape selectivity of the Meso-MFI catalyst. The addition of Pt made the Meso-MFI catalyst even more active in deoxygenation and in the production of aromatics. PMID:22221540

  16. Catalytic pyrolysis of waste rice husk over mesoporous materials

    NASA Astrophysics Data System (ADS)

    Jeon, Mi-Jin; Kim, Seung-Soo; Jeon, Jong-Ki; Park, Sung Hoon; Kim, Ji Man; Sohn, Jung Min; Lee, See-Hoon; Park, Young-Kwon

    2012-01-01

    Catalytic fast pyrolysis of waste rice husk was carried out using pyrolysis-gas chromatography/mass spectrometry [Py-GC/MS]. Meso-MFI zeolite [Meso-MFI] was used as the catalyst. In addition, a 0.5-wt.% platinum [Pt] was ion-exchanged into Meso-MFI to examine the effect of Pt addition. Using a catalytic upgrading method, the activities of the catalysts were evaluated in terms of product composition and deoxygenation. The structure and acid site characteristics of the catalysts were analyzed by Brunauer-Emmett-Teller surface area measurement and NH3 temperature-programmed desorption analysis. Catalytic upgrading reduced the amount of oxygenates in the product vapor due to the cracking reaction of the catalysts. Levoglucosan, a polymeric oxygenate species, was completely decomposed without being detected. While the amount of heavy phenols was reduced by catalytic upgrading, the amount of light phenols was increased because of the catalytic cracking of heavy phenols into light phenols and aromatics. The amount of aromatics increased remarkably as a result of catalytic upgrading, which is attributed to the strong Brönsted acid sites and the shape selectivity of the Meso-MFI catalyst. The addition of Pt made the Meso-MFI catalyst even more active in deoxygenation and in the production of aromatics.

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

    SciTech Connect

    Oyama, Ted; Agblevor, Foster; Battaglia, Francine; Klein, Michael

    2013-01-18

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

  18. Estimating crack growth in temperature damaged concrete

    NASA Astrophysics Data System (ADS)

    Recalde, Juan Jose

    2009-12-01

    Evaluation of the structural condition of deteriorated concrete infrastructure and evaluation of new sustainable cementitious materials require an understanding of how the material will respond to applied loads and environmental exposures. A fundamental understanding of how microstructural changes in these materials relate to changes in mechanical properties and changes in fluid penetrability is needed. The ability to provide rapid, inexpensive assessment of material characteristics and relevant engineering properties is valuable for decision making and asset management purposes. In this investigation, the effects of changes in dynamic elastic properties with water content and fluid penetrability properties before and after a 300°C exposure were investigated based on estimates of the crack density parameter from dry and saturated cracked media. The experimental and analytical techniques described in this dissertation allow calculation of a value for the crack density parameter using nondestructive determination of wet and dry dynamic shear modulus of relatively thin disks. The techniques were used to compare a conventional concrete mixture to several mixtures with enhanced sustainability characteristics. The three enhanced sustainable materials investigated were a very high fly ash mixture, a magnesium phosphate cement based mortar, and a magnesium phosphate cement based concrete, and were compared to a conventional concrete mixture. The analysis provided both quantitative assessment of changes with high temperature damage and autogenous healing, and estimates of changes in mean crack trace lengths. The results showed that water interaction, deterioration due to damage, and autogenous healing recovery were different for the magnesium phosphate cement based mixtures than the portland cement based concrete mixtures. A strong correlation was found between log-transformed Air Permeability Index, dynamic shear modulus, and crack density parameter. The findings imply

  19. Temperature evolution and heat dissipation during crack propagation

    NASA Astrophysics Data System (ADS)

    Lengliné, Olivier; Santucci, Stéphane; Jørgen Måløy, Knut; Vincent-Dospital, Tom; Toussaint, Renaud

    2013-04-01

    During a crack propagation, energy is dissipated in mainly three ways: creation of new fracture surface (possibly at microscopic scale in a process zone), emission of elastic waves that get dissipated in the far field, and local Joule heating during friction in a process zone. There is in addition some reversible elastic energy change associated to the crack advance.Since the temperature variations can have an important impact on the physics of the crack propagation, establishing properly this balance in different crack propagation scenarios is of great importance. Notably, the physics of fracture propagation has been shown to be strongly affected by thermally activated rupture, even when the heterogeneity of material properties determines strongly the microscopic fracture geometry and the intermittency in the fracture propagation. A natural question, in such kinetic crack propagation, is the temperature field during the cracks propagation. This question is also central in earth science, where a lot of attention has been set recently on thermal effects, with the possibility of thermo-pressurization of faults due to thermal expansion of fluids present in faults. Independently of thermo pressurization, the rise of temperature locally, at the zone enduring damage, could significantly affect the creep in this zone, as understood by statistical physics and Arrhenius law, and thus the crack propagation. We are interested in quantifying directly these different effects in an experimental situation. We present results based on infrared and optical imaging of the propagation of a crack in a sheet of paper. The temperature field shows local increases of the temperature of several degrees during the crack propagation. Optical images acquired with a fast video camera are correlated in order to extract the deformation field at each time step. We show how the temperature in our paper sample varies with the deformation rate at the tip of the crack. We also present some numerical

  20. State-of-the-art review of computational fluid dynamics modeling for fluid-solids systems

    NASA Astrophysics Data System (ADS)

    Lyczkowski, R. W.; Bouillard, J. X.; Ding, J.; Chang, S. L.; Burge, S. W.

    1994-05-01

    As the result of 15 years of research (50 staff years of effort) Argonne National Laboratory (ANL), through its involvement in fluidized-bed combustion, magnetohydrodynamics, and a variety of environmental programs, has produced extensive computational fluid dynamics (CFD) software and models to predict the multiphase hydrodynamic and reactive behavior of fluid-solids motions and interactions in complex fluidized-bed reactors (FBR's) and slurry systems. This has resulted in the FLUFIX, IRF, and SLUFIX computer programs. These programs are based on fluid-solids hydrodynamic models and can predict information important to the designer of atmospheric or pressurized bubbling and circulating FBR, fluid catalytic cracking (FCC) and slurry units to guarantee optimum efficiency with minimum release of pollutants into the environment. This latter issue will become of paramount importance with the enactment of the Clean Air Act Amendment (CAAA) of 1995. Solids motion is also the key to understanding erosion processes. Erosion rates in FBR's and pneumatic and slurry components are computed by ANL's EROSION code to predict the potential metal wastage of FBR walls, intervals, feed distributors, and cyclones. Only the FLUFIX and IRF codes will be reviewed in the paper together with highlights of the validations because of length limitations. It is envisioned that one day, these codes with user-friendly pre- and post-processor software and tailored for massively parallel multiprocessor shared memory computational platforms will be used by industry and researchers to assist in reducing and/or eliminating the environmental and economic barriers which limit full consideration of coal, shale, and biomass as energy sources; to retain energy security; and to remediate waste and ecological problems.

  1. Janus droplet as a catalytic micromotor

    NASA Astrophysics Data System (ADS)

    Shklyaev, Sergey

    2015-06-01

    Self-propulsion of a Janus droplet in a solution of surfactant, which reacts on a half of a drop surface, is studied theoretically. The droplet acts as a catalytic motor creating a concentration gradient, which generates its surface-tension-driven motion; the self-propulsion speed is rather high, 60 μ \\text{m/s} and more. This catalytic motor has several advantages over other micromotors: simple manufacturing, easily attained neutral buoyancy. In contrast to a single-fluid droplet, which demonstrates a self-propulsion as a result of symmetry breaking instability, for the Janus one no stability threshold exists; hence, the droplet radius can be scaled down to micrometers.

  2. Evaluation of the irreversible dimensions of radial-circular cracks opened in rock subjected to hydraulic fracturing

    SciTech Connect

    Vouk, A.A.; Beloivan, A.F.; Mikhalyuk, A.V.; Voitenko, Y.I.

    1986-02-01

    The authors propose a method to determine the parameters of radial-circular cracks on the basis of analysis of the interaction between a viscoelastic fluid and an elastobrittle rock under impulse-injection conditions. They examine the horizontal fracture of rock at a depth characteristic for geotechnological wells, where the effect of structural nonuniformities of the rock is insignificant, owing to the presence of a field of compressive stresses, and an initial crack of the required dimensions which initiates the failure is created by familiar technical methods. The viscous flow of fluid in the crack is a basic factor that slows crack development in the absence of vigorous seepage of fluid. In the case of hydraulic fracturing with a fluid having a high viscosity with other conditions equal, the authors expect that the radius of the crack will be smaller than that during fracturing with a low-viscosity fluid.

  3. Refinery ring groove cracking experience

    SciTech Connect

    Ehmke, E.F.

    1982-05-01

    This paper presents the results of a questionnaire on the problem of ring groove cracking in reactors. The results were found to be inconclusive in providing any information on correcting the problem. One report pertaining to a ring groove crack on a 24-inch reactor nozzle served as a warning that cracks may progress beyond the overlay, through it is not known if the base metal can easily crack at low temperatures. The results did not indicate at what point the cracks occurred, but what was common to almost all cracks was that the flange had been in high-temperature, high-pressure hydrogen suggesting that dissolved hydrogen or environmental hydrogen assisted the cracking. The type of stress that contributes in the cracking has not been determined. It is indicated that many cracks were found after the questionnaire was done.

  4. The dependence of acoustic properties of a crack on the resonance mode and geometry

    USGS Publications Warehouse

    Kumagai, H.; Chouet, B.A.

    2001-01-01

    We examine the dependence of the acoustic properties of a crack containing magmatic or hydrothermal fluids on the resonance mode and geometry to quantify the source properties of long-period (LP) events observed in volcanic areas. Our results, based on spectral analyses of synthetic waveforms generated with a fluid-driven crack model, indicate that the basic features of the dimensionless frequency (??) and quality factor (Qr) for a crack containing various types of fluids are not strongly affected by the choice of mode, although the actual ranges of Q?? and ?? both depend on the mode. The dimensionless complex frequency systematically varies with changes in the crack geometry, showing increases in both Qr and ?? as the crack length to aperture ratio decreases. The present results may be useful for the interpretation of spatial and temporal variations in the observed complex frequencies of LP events.

  5. Two stage catalytic combustor

    NASA Technical Reports Server (NTRS)

    Alvin, Mary Anne (Inventor); Bachovchin, Dennis (Inventor); Smeltzer, Eugene E. (Inventor); Lippert, Thomas E. (Inventor); Bruck, Gerald J. (Inventor)

    2010-01-01

    A catalytic combustor (14) includes a first catalytic stage (30), a second catalytic stage (40), and an oxidation completion stage (49). The first catalytic stage receives an oxidizer (e.g., 20) and a fuel (26) and discharges a partially oxidized fuel/oxidizer mixture (36). The second catalytic stage receives the partially oxidized fuel/oxidizer mixture and further oxidizes the mixture. The second catalytic stage may include a passageway (47) for conducting a bypass portion (46) of the mixture past a catalyst (e.g., 41) disposed therein. The second catalytic stage may have an outlet temperature elevated sufficiently to complete oxidation of the mixture without using a separate ignition source. The oxidation completion stage is disposed downstream of the second catalytic stage and may recombine the bypass portion with a catalyst exposed portion (48) of the mixture and complete oxidation of the mixture. The second catalytic stage may also include a reticulated foam support (50), a honeycomb support, a tube support or a plate support.

  6. Subcritical crack growth in glasses under cyclic loads: Effect of hydrodynamic pressure in aqueous environments

    SciTech Connect

    Yi, K.S.; Dill, S.J.; Dauskardt, R.H.

    1997-07-01

    The effect of hydrodynamic pressure developed in the wake of a crack growing in a brittle material under cyclic loads in an aqueous environment is considered. The pressure acts in opposition to the movement of the crack faces, thus shielding the crack up from the applied loads. A general hydrodynamic fluid pressure relation based on a one-dimensional Reynolds equation, which applicable to a crack with an arbitrary crack opening profile, is developed. The model is modified to account for side flow through the thickness of the sample and cavitation near the crack tip. Both effects significantly modify the hydrodynamic pressure distribution. Finally, the resulting hydrodynamic pressure relations are combined with a fracture mechanics model to account for the change in the near-tip stress intensity. Resulting predictions of the cyclic crack-growth rate are found to be in good agreement with measured values for a borosilicate glass tested at various frequencies in a water environment.

  7. Surface crack problems in plates

    NASA Technical Reports Server (NTRS)

    Joseph, P. F.; Erdogan, F.

    1989-01-01

    The mode I crack problem in plates under membrane loading and bending is reconsidered. The purpose is to examine certain analytical features of the problem further and to provide some new results. The formulation and the results given by the classical and the Reissner plate theories for through and part-through cracks are compared. For surface cracks the three-dimensional finite element solution is used as the basis of comparison. The solution is obtained and results are given for the crack/contact problem in a plate with a through crack under pure bending and for the crack interaction problem. Also, a procedure is developed to treat the problem of subcritical crack growth and to trace the evolution of the propagating crack.

  8. Catalytic distillation structure

    DOEpatents

    Smith, Jr., Lawrence A.

    1984-01-01

    Catalytic distillation structure for use in reaction distillation columns, a providing reaction sites and distillation structure and consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and being present with the catalyst component in an amount such that the catalytic distillation structure consist of at least 10 volume % open space.

  9. Cracking the Credit Hour

    ERIC Educational Resources Information Center

    Laitinen, Amy

    2012-01-01

    The basic currency of higher education--the credit hour--represents the root of many problems plaguing America's higher education system: the practice of measuring time rather than learning. "Cracking the Credit Hour" traces the history of this time-based unit, from the days of Andrew Carnegie to recent federal efforts to define a credit hour. If…

  10. Performance characterization of a hydrogen catalytic heater.

    SciTech Connect

    Johnson, Terry Alan; Kanouff, Michael P.

    2010-04-01

    This report describes the performance of a high efficiency, compact heater that uses the catalytic oxidation of hydrogen to provide heat to the GM Hydrogen Storage Demonstration System. The heater was designed to transfer up to 30 kW of heat from the catalytic reaction to a circulating heat transfer fluid. The fluid then transfers the heat to one or more of the four hydrogen storage modules that make up the Demonstration System to drive off the chemically bound hydrogen. The heater consists of three main parts: (1) the reactor, (2) the gas heat recuperator, and (3) oil and gas flow distribution manifolds. The reactor and recuperator are integrated, compact, finned-plate heat exchangers to maximize heat transfer efficiency and minimize mass and volume. Detailed, three-dimensional, multi-physics computational models were used to design and optimize the system. At full power the heater was able to catalytically combust a 10% hydrogen/air mixture flowing at over 80 cubic feet per minute and transfer 30 kW of heat to a 30 gallon per minute flow of oil over a temperature range from 100 C to 220 C. The total efficiency of the catalytic heater, defined as the heat transferred to the oil divided by the inlet hydrogen chemical energy, was characterized and methods for improvement were investigated.