Zeolite Supported Iron Cobalt Catalysts For The Fischer Tropsch Synthesis

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.

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.

The declining supply of crude oils worldwide and the ever increasing demand for petroleum products from China, India, Europe and the US have recently propelled crude prices to unprecedented levels. The future availability of traditional crudes is becoming a source of discussion and debate.Fischer-Tropsch Synthesis, Catalysts and Catalysis offers a timely and comprehensive report on the processing of relatively inexpensive coal deposits into transportation fluids using Fisher-Tropsch process Technology. In addition to recent catalysts and process developments, the book contains the history of the Fisher-Tropsch in Germany and Japan based on captured documents by allied forces. * Increase the understanding of FT process development* Addresses four major areas of interest in Fischer-Tropsch synthesis (FTS)

A síntese de Fischer-Tropsch converte o gás de síntese (H2 + CO), em umavariedade complexa de hidrocarbonetos na presença de um catalisador(principalmente Co/Al2O3). Neste trabalho foram estudados catalisadores de Co eo Fe (1 e 5% em massa), incorporados aos suportes: zeólitas KL, HL 0,1M e HL1,0 M, além da peneira molecular mesoporosa MCM- 41, pelo método deimpregnação úmida incipiente, para a reação de Fischer-Tropsch. As amostras preparadas foram analisadas pelas técnicas de: Espectometriade Emissão Atômica de Plasma Acoplado Induzido, Adsorção Física de N2 pelométodo BET, Difração de Raios-X, Redução com Temperatura Programada, Microscopia Eletrônica de Transmissão (MET), Quimissorção de Hidrogênio eEspectroscopia no Infravermelho de piridina adsorvida. Além disso, as amostrasforam avaliadas em um reator de leito fixo na reação de Fischer-Tropsch. Para as amostras de ferro, com mesmo teor e suportes diferentes, pode-seobservar que a amostra suportada na MCM-41 apresentou um grau de reduçãomenor. Entre as amostras de ferro suportadas na KL, a 5% Fe/KL apresentoumaior grau de redução e foi observado por microscopia eletrônica de transmissão(MET) que as partículas de ferro apresentaram diâmetro em torno de 6 nm. Para as amostras de cobalto foi observado que a temperatura de redução daamostra suportada na MCM-41 foi mais alta. A amostra 5% Co/KL apresentouum maior grau de redução. Foi possível observar por MET que as partículas decobalto apresentaram diâmetro variando entre 8 e 20 nm. Verificou-se que o catalisador com maior teor de ferro proporcionou uma maiorconversão de CO, tendo sido a distribuição de produtos deslocada para as fraçõesmais leves. Comparando os catalisadores de ferro suportados na zeólita KL e naMCM-41 pode-se concluir que as conversões são da mesma ordem de grandeza. Foi observado que o ferro foi mais ativo que o cobalto em termos de conversão do CO, sendo que o cobalto promoveu a formação de uma maior quantidade deprodutos na faixa de diesel, assim como uma menor quantidade de leves.

Currently, cobalt and related catalysts are very attractive as they provide many advantages, such as low cost and high activity, in a variety of applications. Cobalt catalysts are among the most active catalysts for Fischer-Tropsch synthesis and they promote the catalytic activity of the hydrodesulfurization catalysts. They also found other significant applications in environmental protection such as oxidation of volatile organic compounds, VOC, persulfate activator, ammonia synthesis, electrocatalysis and many more. Cobalt catalysts are active, stable and exhibit significant oxidation-reduction activity, as the Co can be found either as Co(II) or Co(III). Additionally, many molecules can interact with the cobalt supported phase by co-ordination due to partially filled d-orbital. Co-catalysts can be supported in almost all the inorganic supports such as alumina, titania, zeolites, etc. The cobalt oxide phase can be stabilized on the surface of the support due to variable interactions between the support and cobalt phase. These interactions are crucial for catalytic activity and can be regulated by proper selection of the preparation parameters such as the type of support, the Co loading, impregnation method and thermal conditions.

Currently, cobalt and related catalysts are very attractive as they provide many advantages, such as low cost and high activity, in a variety of applications. Cobalt catalysts are among the most active catalysts for Fischer-Tropsch synthesis and they promote the catalytic activity of the hydrodesulfurization catalysts. They also found other significant applications in environmental protection such as oxidation of volatile organic compounds, VOC, persulfate activator, ammonia synthesis, electrocatalysis and many more. Cobalt catalysts are active, stable and exhibit significant oxidation-reduction activity, as the Co can be found either as Co(II) or Co(III). Additionally, many molecules can interact with the cobalt supported phase by co-ordination due to partially filled d-orbital. Co-catalysts can be supported in almost all the inorganic supports such as alumina, titania, zeolites, etc. The cobalt oxide phase can be stabilized on the surface of the support due to variable interactions between the support and cobalt phase. These interactions are crucial for catalytic activity and can be regulated by proper selection of the preparation parameters such as the type of support, the Co loading, impregnation method and thermal conditions.This Special Issue aims to cover recent progress and advances in the field of cobalt and related catalysts.