Author: Andrew Ronald Raub Publisher: ISBN: Category : Catalyst supports Languages : en Pages : 0
Book Description
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.
Author: Wilson D. Shafer Publisher: MDPI ISBN: 303928388X Category : Science Languages : en Pages : 414
Book Description
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.
Author: A. Parmaliana Publisher: Elsevier ISBN: 0080537308 Category : Technology & Engineering Languages : en Pages : 1005
Book Description
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 Description
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
Author: B. H. Davis Publisher: CRC Press ISBN: 1420062573 Category : Science Languages : en Pages : 430
Book Description
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
Author: Publisher: ISBN: Category : Aluminum oxide Languages : en Pages : 252
Book Description
Effect of alumina support modification for applications as cobalt and iron catalyst supports in Fischer-Tropsch reaction were studied. Alumina supports consisting of various gamma to chi ratios were prepared using solvothermal method and employed as supports for cobalt catalysts. In order to identify the characteristics, all the catalysts were characterized using surface area analysis, X-ray diffraction (XRD), Scanning electron microscopy2Energy dispersive X-ray (SEM/EDX), Transmission electron microscopy (TEM), Fourier transform Infrared Spectroscopy (FT-IR), Temperature programmed reduction (TPR), and hydrogen and carbon monoxide chemisorption. CO hydrogenation (H 2CO = 10/1) was also performed to determine the overall activity and selectivity of the Co/AL O catalysts containing various gamma to chi ratios. It was found that both activity and selectivity were increased with increasing the chi to gamma ratios of the alumina supports. It is suggested that the spherical;-shape like morphology of the -phase AL O provide better stability and dispersion of the Co particles. In addition, the effect of Cu-modification of alumina support for applications as iron catalyst supports in Fischer-Tropsch reaction (H 2CO - 2/1) was also investigated. It was found that the use of copper-modified alumina supports enhanced both reducibilities and the overall activities of Fe/AL O catalysts. However, Cu-modification of alumina support appeared to have no effect on selectivity of the F-T products.
Author: Andrew Ronald Raub
Author: Shiro Watanabe
Author: Abegail Tebogo Bopape
Author: Wilson D. Shafer
Author: A. Parmaliana
Author: André Steynberg
Author: Danny Chien Lu
Author: B. H. Davis
Author: 
Author: Ashish S. Bambal