Preparation Of Active Stable Supported Iron Catalysts And Deactivation By Carbon Of Cobalt Catalysts For Fischer Tropsch Synthesis

The second half of this dissertation investigates the effects of operating conditions including the partial pressures of CO and H2 and temperature on the deactivation by carbon of 25 wt% Co/ 0.25 wt% Pt/Al2O3 catalyst. It also reports the kinetics of the main FT reaction on this catalyst. As temperature increases, the H2 and CO orders for the main reaction (in the absence of deactivation) become more positive and more negative, respectively. A new mechanism was proposed to account for the inhibition effect of CO at high reaction temperatures, which includes H-assisted dissociation of CO to C* and OH*. Further, twelve samples of the CoPt/Al2O3 catalyst were tested over a period of 800 hours and XCO

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.

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.

Rising oil costs have stimulated significant interest in the Fischer-Tropsch synthesis (FTS) as a method for producing a synthetic petroleum substitute. Drawn from the proceedings at a symposium held during the 236th meeting of the American Chemical Society in Philadelphia in August 2008, Advances in Fischer-Tropsch Synthesis, Catalysts, and Cataly

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.

Catalysis, in the industrial production of chemicals, fuels, and materials, accounts for more than half of gross material production worldwide. Heterogeneous catalysis enables fast and selective chemical transformations, resulting in superior product yield and facilitating catalyst separation and recovery. The synthesis of novel catalysts has emerged as a hot topic for process and product development with numerous research publications and patents. Hence, development of efficient catalysts and their applications is important for sustainable energy production and use, green chemicals production and use, and economic growth. This Special Issue discusses recent developments related to catalysis for the production of sustainable fuels and chemicals and traverses many new frontiers of catalysis including synthesis, characterization, catalytic performances, reaction kinetics and modelling, as well as applications of catalysts for the production of biofuels, synthesis gas, and other green products. This covers the current state-of-the-art catalysis research applied to bioenergy, organic transformation, carbon–carbon and carbon–heteroatoms, reforming, hydrogenation, hydrodesulfurization, hydrodenitrogenation, hydrodemetalization, Fischer–Tropsch synthesis, to name a few. This book highlights new avenues in catalysis including catalyst preparation methods, analytical tools for catalyst characterization, and techno-economic assessment to enhance a chemical or biological transformation process using catalysts for a betterment of industry, academia and society.

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