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Cobalt Fischer Tropsch Catalysts Having Improved Selectivity
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Book Synopsis Cobalt Fischer-Tropsch Catalysts Having Improved Selectivity by :
Download or read book Cobalt Fischer-Tropsch Catalysts Having Improved Selectivity written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A cobalt Fischer-Tropsch catalyst having an improved steam treated, acid extracted LZ-210 support is taught. The new catalyst system demonstrates improved product selectivity at Fischer-Tropsch reaction conditions evidenced by lower methane production, higher C.sub. 5.sup.+ yield and increased olefin production.
Book Synopsis Iron and Cobalt Catalysts by : Wilson D. Shafer
Download or read book Iron and Cobalt Catalysts written by Wilson D. Shafer and published by MDPI. This book was released on 2020-06-23 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the turn of the last century when the field of catalysis was born, iron and cobalt have been key players in numerous catalysis processes. These metals, due to their ability to activate CO and CH, haev a major economic impact worldwide. Several industrial processes and synthetic routes use these metals: biomass-to-liquids (BTL), coal-to-liquids (CTL), natural gas-to-liquids (GTL), water-gas-shift, alcohol synthesis, alcohol steam reforming, polymerization processes, cross-coupling reactions, and photocatalyst activated reactions. A vast number of materials are produced from these processes, including oil, lubricants, waxes, diesel and jet fuels, hydrogen (e.g., fuel cell applications), gasoline, rubbers, plastics, alcohols, pharmaceuticals, agrochemicals, feed-stock chemicals, and other alternative materials. However, given the true complexities of the variables involved in these processes, many key mechanistic issues are still not fully defined or understood. This Special Issue of Catalysis will be a collaborative effort to combine current catalysis research on these metals from experimental and theoretical perspectives on both heterogeneous and homogeneous catalysts. We welcome contributions from the catalysis community on catalyst characterization, kinetics, reaction mechanism, reactor development, theoretical modeling, and surface science.
Book Synopsis Natural Gas Conversion V by : A. Parmaliana
Download or read book Natural Gas Conversion V written by A. Parmaliana and published by Elsevier. This book was released on 1998-09-17 with total page 1005 pages. Available in PDF, EPUB and Kindle. Book excerpt: On January 1988, the ascertained and economically accessible reserves of Natural Gas (NG) amounted to over 144,000 billion cubic meters worldwide, corresponding to 124 billion tons of oil equivalents (comparable with the liquid oil reserves, which are estimated to be 138 billion TOE). It is hypothesized that the volume of NG reserve will continue to grow at the same rate of the last decade. Forecasts on production indicate a potential increase from about 2,000 billion cubic meters in 1990 to not more than 3,300 billion cubic meters in 2010, even in a high economic development scenario. NG consumption represents only one half of oil: 1.9 billion TOE/y as compared to 3.5 of oil. Consequently, in the future gas will exceed oil as a carbon atom source. In the future the potential for getting energetic vectors or petrochemicals from NG will continue to grow. The topics covered in Natural Gas Conversion V reflect the large global R&D effort to look for new and economic ways of NG exploitation. These range from the direct conversion of methane and light paraffins to the indirect conversion through synthesis gas to fuels and chemicals. Particularly underlined and visible are the technologies already commercially viable. These proceedings prove that mature and technologically feasible processes for natural gas conversion are already available and that new and improved catalytic approaches are currently developing, the validity and feasibility of which will soon be documented. This is an exciting area of modern catalysis, which will certainly open novel and rewarding perspectives for the chemical, energy and petrochemical industries.
Book Synopsis Fischer-Tropsch Technology by : André Steynberg
Download or read book Fischer-Tropsch Technology written by André Steynberg and published by Elsevier. This book was released on 2004-10-30 with total page 722 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fischer-Tropsch Technology is a unique book for its state-of-the-art approach to Fischer Tropsch (FT) technology. This book provides an explanation of the basic principles and terminology that are required to understand the application of FT technology. It also contains comprehensive references to patents and previous publications. As the first publication to focus on theory and application, it is a contemporary reference source for students studying chemistry and chemical engineering. Researchers and engineers active in the development of FT technology will also find this book an invaluable source of information. * Is the first publication to cover the theory and application for modern Fischer Tropsch technology * Contains comprehensive knowledge on all aspects relevant to the application of Fischer Tropsch technology* No other publication looks at past, present and future applications
Book Synopsis Fischer-Tropsch Synthesis, Catalysts, and Catalysis by : Burtron H. Davis
Download or read book Fischer-Tropsch Synthesis, Catalysts, and Catalysis written by Burtron H. Davis and published by CRC Press. This book was released on 2016-04-06 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based on a symposium held during the 248th American Chemical Society meeting that focused on use of the Fischer-Tropsch process in producing synthetic fuels. Its contents reflect the four dominant subjects of the meeting: catalyst preparation and activation, catalyst activity and reaction mechanisms, catalyst characterization and related reactions, and topics concerning commercializing the Fischer-Tropsch process. It covers recent developments related to renewable resources and green energy and provides a glimpse of the commercial potential of the Fischer-Tropsch process in synthetic fuel production.
Book Synopsis Kinetics and Selectivity in Fischer-Tropsch Synthesis on a Cobalt Catalyst by : Bent Sarup
Download or read book Kinetics and Selectivity in Fischer-Tropsch Synthesis on a Cobalt Catalyst written by Bent Sarup and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Catalysis in the Refining of Fischer-Tropsch Syncrude by : Arno de Klerk
Download or read book Catalysis in the Refining of Fischer-Tropsch Syncrude written by Arno de Klerk and published by Royal Society of Chemistry. This book was released on 2010 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first book to provide a review of the literature on the catalysis needed to refine syncrude to transportation fuels.
Book Synopsis Metal Oxide Promotion of Cobalt-Based Fischer-Tropsch Synthesis Catalysts by : Gregory Robert Johnson
Download or read book Metal Oxide Promotion of Cobalt-Based Fischer-Tropsch Synthesis Catalysts written by Gregory Robert Johnson and published by . This book was released on 2015 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthetic fuel production by means of Fischer-Tropsch synthesis (FTS) involves the catalytic hydrogenation of CO over Co-based catalysts. Often, these catalysts incorporate performance-enhancing additives known as promoters. Although not catalytically active for FTS by themselves, promoters can alter the structural and electronic properties of the active Co metal so as to improve catalyst activity, selectivity, or stability. Elements that form metal oxides have been studied for their ability to increase CO consumption rates and shift the product distribution toward higher molecular weight. Despite several decades of study of such elements, there remains limited understanding of the connections between these promotional effects and element properties. Accordingly, this dissertation focuses on clarifying the chemical basis for the effects of metal oxide promotion and making connections to periodic trends. To understand the importance of physical contact between the promoter and the Co, the influence of Co-Mn spatial association on the magnitude of Mn promotional effects was investigated. Elemental maps obtained by STEM-EDS revealed that different catalyst pretreatment methods could control how closely associated the promoter and Co were at the nanoscale. By relating these results to catalytic reaction data, it was determined that higher extents of contact between the two elements were correlated with higher selectivities toward C5+ hydrocarbons. This work was extended to the elements Ce, Gd, La, and Zr, which are among the most commonly studied metal oxide-forming promoters. The presence of the promoter element suppressed methane formation and increased the FTS chain propagation probability, but the sensitivity of these effects toward promoter loading was different for each element. Elements that deposited preferentially onto the Co nanoparticles led to rapid shifts in the product distribution as the promoter loading increased, whereas elements that dispersed over the entire catalyst surface resulted in more gradual changes. For all promoters, the product selectivities became insensitive to loading when the loading reached a quantity nearly equivalent to that which would form a half monolayer of the promoter on the Co nanoparticle surface. These trends are characteristic of the formation of active sites along the interface between the Co and the promoter that exhibit improved product selectivity. Structurally, the oxidation states and local coordination environments of the promoters were consistent with highly dispersed oxides. No evidence for the formation of bimetallic alloys or large promoter-containing crystallites was detected by either X-ray absorption spectroscopy or X-ray diffraction. These data suggest that small promoter oxide moieties decorate the surface of the Co metal nanoparticles so as to form metal-metal oxide interfaces. Under this model, the promotional effects increase in magnitude as the fraction of Co active sites that are adjacent to the promoter increases. When the Co surface is sufficiently covered by the promoter so that the fraction of active sites that are along the perimeter of the promoter moieties is nearly unity, the catalyst performance ceases to improve as a function of promoter loading. Guided by this reasoning, the catalytic properties of the promoted catalysts were investigated using samples in which the fraction of sites that were promoted was near unity. Measurements of reaction kinetics were conducted to assess the impact of metal oxide promotion on the rate parameters governing FTS. The rates of CO consumption for both unpromoted and metal oxide-promoted catalysts followed a Langmuir-Hinshelwood rate law for which H-assisted CO dissociation is assumed to be the rate determining step. Each promoter increased the apparent rate constant and the CO adsorption constant that appear within the rate law. Thus, metal oxide promotion appears both to facilitate the cleavage of the C-O bond and to enhance the extent of CO adsorption onto the catalyst. This finding was reinforced by CO temperature programmed desorption experiments and an evaluation of the effects of Mn promotion on the rate of CO disproportionation. Owing to the appearance of the CO adsorption constant in the numerator and denominator of the rate law, it is possible for promoted catalysts to have both higher and lower turnover frequencies than unpromoted catalysts depending on the chosen operating pressure. As a consequence, an optimal promoter can be found for maximizing the turnover frequency at a given operating pressure. However, product selectivity, which is largely determined by the availability of adsorbed H, is invariably improved by a higher CO adsorption constant because it decreases the ratio of adsorbed H to CO on the Co surface. Strong correlations between catalyst performance and the Lewis acidity of the promoter oxide suggest that Lewis acid-base interactions between the promoter and the adsorbed CO are the cause for the observed metal oxide promotional effects. Much of the experimental data presented in this work favors the hypothesis that CO can interact simultaneously with Co through the C atom and with the promoter cation through the O atom. These chemical interactions, in which the promoter serves as a Lewis acid, weaken the bond between C and O. Experimental evidence for this effect was observed in the lower activation barrier for CO hydrogenation over the ZrO2-promoted catalysts and the appearance of adsorbed carbonyl species on the MnO-promoted catalyst with severely redshifted C-O stretching frequencies measured by in situ infrared spectroscopy. These results provide insight into the chemical mechanism by which metal oxides affect the reaction and identify Lewis acidity of the promoter as the relevant descriptor for quantitatively predicting metal oxide-based promotional effects over Co FTS catalysts.
Download or read book Catalysis written by James J Spivey and published by Royal Society of Chemistry. This book was released on 2013-03-11 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over 7000 papers are published in the field of catalysis each year. While the majority appear within a handful publications, keeping up with the literature can be difficult. Now in its 25th volume, the Specialist Periodical Report on Catalysis presents critical and comprehensive reviews of the hottest literature published over the last twelve months. Industrial and academic scientists face increasing challenges to find cost-effective and environmentally sound methods for converting natural resources into fuels, chemicals and energy. This series is edited by two leading researchers in the field and provides a balanced and in-depth review of the modern approaches to these challenges, covering major areas of heterogeneous and homogenous catalysis, as well as specific applications of catalysis, such as NOx control, kinetics and experimental techniques, such as microcalorimetry. With chapters detailing specific areas within the field, this series is a comprehensive reference for anyone working in Catalysis and an essential resource for any Chemistry Library.
Book Synopsis Technology Development for Iron and Cobalt Fischer-Tropsch Catalysts by :
Download or read book Technology Development for Iron and Cobalt Fischer-Tropsch Catalysts written by and published by . This book was released on 1999 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: The impact of deuterium on the Fischer-Tropsch (FT) synthesis was studied with a precipitated iron catalyst in the slurry phase. Deuterium has been used by several research groups to better understand the mechanism of CO hydrogenation. Inverse (k{sub H}/k{sub D} 1), normal (k{sub H}/k{sub D} 1) and no isotope effect (k{sub H}/k{sub D} = 1) have been reported. The conflicting results are thought to arise because rate of reaction is a combination of kinetic and equilibrium factors. In summary, the presence of boron produced only minor changes on the properties of the cobalt catalyst. In earlier studies, it was shown that the presence of boron made the catalyst less susceptible to poisoning by sulfur. Steady-state supercritical Fischer-Tropsch synthesis was studied in the work using a fixed-bed reactor and an unpromoted Co/SiO2 catalyst. This serves as the baseline for promoted catalyst studies. A pentane-hexane mixture was used as the supercritical solvent. Overall reactor pressure, syngas partial pressure and contact time were kept constant to obtain a valid comparison of the impact of solvent density in the catalytic activity and selectivity. Three different partial pressures of the mixture were chosen based on the density-pressure curve in order to investigate the pressure tuning effect to Fischer-Tropsch synthesis near critical region.
Author :Christopher Jason Bertole Publisher :National Library of Canada = Bibliothèque nationale du Canada ISBN 13 :9780612691001 Total Pages :490 pages Book Rating :4.6/5 (91 download)
Book Synopsis Site-activity, Active Carbon Coverage and Methane Selectivity of Cobalt Fischer-Tropsch Catalysts [microform] : Effects of Catalyst Composition and Reaction Conditions by : Christopher Jason Bertole
Download or read book Site-activity, Active Carbon Coverage and Methane Selectivity of Cobalt Fischer-Tropsch Catalysts [microform] : Effects of Catalyst Composition and Reaction Conditions written by Christopher Jason Bertole and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 2002 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Fischer-Tropsch Reaction Over Ti-Modified Cobalt Catalysts by : Andrew Ronald Raub
Download or read book The Fischer-Tropsch Reaction Over Ti-Modified Cobalt Catalysts written by Andrew Ronald Raub and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents research done to investigate the promoter effects of small amounts of titanium oxides (TiOx) on unsupported cobalt metal catalysts for the atmospheric pressure Fischer-Tropsch (CO+H2) reaction. It is known that cobalt catalysts with TiO2 supports can have their performance for the Fischer-Tropsch reaction enhanced due to interactions between cobalt metal and the support. Small TiOx species can migrate onto the surface of metal particles during reductive treatment, termed the "strong metal-support interaction" (SMSI). Interactions between TiOx species and the cobalt metal are expected to influence its catalytic behavior. Techniques were developed to create unsupported cobalt metal catalysts dosed with controlled amounts of TiOx via oxalate precursors. By eliminating the presence of a supporting material, interactions between cobalt metal and TiOx could be focused on. This is the first time that TiOx alone has been studied as a promoter species in controlled amounts over an unsupported cobalt catalyst for the atmospheric pressure CO+H2 reaction.Steady state and chemical transient kinetic (CTK) reaction studies revealed that very small amounts of Ti (~1-2 atom%, relative to cobalt) induce changes in the catalyst structure and product selectivity. The addition of TiOx to the cobalt resulted in increased selectivity toward alkenes and suppression of CH4 and C2H6 that persisted over long reaction times. When TiOx is present, CTK measurements revealed the presence of surface intermediates that are absent over pure cobalt and react with different kinetics to form chain lengthened hydrocarbons. Estimated carbon amounts on the catalyst surfaces showed ~3 carbon atoms/cobalt metal site for pure cobalt catalysts, and ~5-6 carbon atoms/cobalt metal site for Ti-modified cobalt catalysts. General observations made about formation and decay behavior for hydrocarbon products during CTK studies were in good agreement with those obtained for similar work done on CoMgO and CoMnOx catalysts. Suggestions for the direction of future work on Ti-modified cobalt catalysts are made at the end of this dissertation.Some effort has also been spent on using methyl formate, which can be considered a liquid form of syngas, to produce chain lengthened hydrocarbons using CoMnTi catalysts. This ternary catalyst composition was selected due to its industrial relevance. Some transient kinetic studies were performed but turned out challenging to interpret due to the complexity of parallel decomposition pathways for methyl formate. In view of the complexity of the CoMnTi catalyst composition, it was deemed important to first focus on the CoTi case as a prerequisite for studying more complicated catalyst formulations.
Book Synopsis Morphological, Compositional, and Shape Control of Materials for Catalysis by : Paolo Fornasiero
Download or read book Morphological, Compositional, and Shape Control of Materials for Catalysis written by Paolo Fornasiero and published by Elsevier. This book was released on 2017-05-23 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt: Morphological, Compositional, and Shape Control of Materials for Catalysis, Volume 177, the latest in the Studies in Surface Science and Catalysis series, documents the fast-growing developments in the synthesis, characterization, and utilization of nanostructures for catalysis. The book provides essential background on using well-defined materials for catalysis and presents exciting new paradigms in the preparation and application of catalytic materials, with an emphasis on how structure determines catalytic properties. In addition, the book uniquely features discussions on the future of the field, with ample space for future directions detailed in each chapter. Presents the latest paradigms in the preparation and application of catalytic materials Provides essential background on using well-defined materials for catalysis Features discussion of future directions at the end of each chapter
Book Synopsis Slurry Phase Fischer-Tropsch Synthesis by :
Download or read book Slurry Phase Fischer-Tropsch Synthesis written by and published by . This book was released on 1988 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: A cobalt Fischer-Tropsch catalyst (CO/MgO/silica) was reduced and slurried in combination with reduced Cu/ZnO/Al[sub 2]0[sub 3] water-gas-shift catalyst. Combined catalyst system was run at fixed process conditions for more than 400 hours. The system showed stable selectivity. The Cu/ZnO/Al[sub 2]0[sub 3] water-gas-shift catalyst remained reasonably active in the presence of the cobalt catalyst. Hydrocarbon selectivity of the cobalt and Cu/ZnO/Al[sub 2]0[sub 3] catalyst system compared favorably to selectivity of iron-based catalysts. Methane selectivity was slightly higher for the cobalt-based system, but C[sub 5][sup +] selectivity was essentially the same. The hydrocarbon product distribution appeared to exhibit a double-a behavior. a[sub 1] was near 0.80 which is higher than that of iron catalysts, while a[sub 2] was calculated to be 0.86 which is somewhat lower than would be typical for an iron-based catalyst.
Book Synopsis Development of a Stable Cobalt-ruthenium Fischer-Tropsch Catalyst by :
Download or read book Development of a Stable Cobalt-ruthenium Fischer-Tropsch Catalyst written by and published by . This book was released on 1991 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this contract is to examine the relationship between catalytic properties and the function of cobalt Fischer-Tropsch catalysts and to apply this fundamental knowledge to the development of a stable cobalt-based catalyst with a low methane-plus-ethane selectivity for use in slurry reactors. An experimental cobalt catalyst 585R2723 was tested three times in the fixed-bed reactor. The objective of the tests was to identify suitable testing conditions for screening catalyst. The?-alumina was determined to be a suitable diluent medium for controlling the catalyst bed temperature close to the inlet temperature. With 13 g of catalyst and 155 g of diluent, the catalyst maximum temperature were within 2°C from the inlet temperatures. As a result of this work, 210°C and 21 atm were shown to result in low methane selectivity and were used as initial conditions in the catalyst screening test. Ethane, which along with methane is undesirable, is typically produced with low selectivity and follows the same trend as methane. Other work reported here indicated that methane selectivity increases with increasing temperature but is not excessively high at 230°C. Consequently, the catalyst screening test should include an evaluation of the catalyst performance at 230°C. During Run 67, the increase in temperature from 210°C to 230°C was initiated at 30 hours on-stream.
Book Synopsis The Chemistry of the Catalyzed Hydrogenation of Carbon Monoxide by : G. Henrici-Olive
Download or read book The Chemistry of the Catalyzed Hydrogenation of Carbon Monoxide written by G. Henrici-Olive and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the oil embargo, in the winter 1973174, parts of Western Europe present ed an almost war-like aspect on Saturdays and Sundays: no traffic on the high ways, no crowds at ski resorts and other weekend entertainment places, no gaso line at the pumps. Living and teaching then in that part of the world, and discussing the situa tion with our students, we came to the conclusion that it would be timely to col lect the fine chemistry already known at the time in the field of conversion of coal to gasoline and other chemicals, and by this way help to draw the attention to this important alternative to crude oil. The idea of this book was born. The energy shock of the early seventies has been healthy and of great conse quences in chemistry. Large amounts of research money have been put to work since, and our knowledge of the possibilities and limitations of coal-based chemistry has increased enormously. During several years it appeared inap propriate to write a monograph about a topic which was in the midst of such an impetuous development. Nevertheless, we collected, and critically selected, the upcoming work as it appeared in the literature, and also tried to provide some modest input ourselves. Now, ten years later, the situation seems to be settled to a certain degree.
Book Synopsis Investigation of Intrinsic Activity of Cobalt and Iron Based Fischer-Tropsch Catalysts Using Transient Kinetic Methods by : Alexandre Antônio Bento Carvalho
Download or read book Investigation of Intrinsic Activity of Cobalt and Iron Based Fischer-Tropsch Catalysts Using Transient Kinetic Methods written by Alexandre Antônio Bento Carvalho and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work exposed in this manuscript concerns the study of the intrinsic activity and localization of active sites in cobalt and iron based catalysts using a combination of transient kinetic methods such as SSITKA, extended physicochemical characterization and catalytic tests under quasi steady state conditions. Promotion of iron catalysts with metals used for soldering (Bi and Pb) results a remarkable increase in the light olefin production rate with the possibility to conduct Fischer-Tropsch synthesis at very mild reaction conditions (low pressure) and even at atmospheric pressure. Transient kinetic experiments showed facilitation of CO dissociation in the presence of promoters by scavenging O atoms from iron carbide. Cobalt catalyst supported by mordenite zeolite presented higher value of SSITKA rate constant. Localization of cobalt active sites in bifunctional cobalt-zeolite catalysts has a major impact on the reaction rate and in particular on the hydrocarbon selectivity. A proximity between the cobalt active site and Bronsted active sites was found to be a key parameter to obtain higher selectivity and yield of isomerized hydrocarbons. SSITKA combined with catalyst characterization revealed that carbon deposition and cobalt nanoparticle agglomeration were responsible for the deactivation of silica supported cobalt catalysts. Catalyst rejuvenation in hydrogen lessened the amounts of deposited carbon species and partially released the most active sites of carbon monoxide dissociative adsorption and stronger sites of carbon monoxide reversible adsorption.
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