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Author : Rama Krishna Manne
Publisher :
ISBN 13 :
Total Pages : 306 pages
Book Rating : 4.:/5 (332 download)
Download or read book Activation Studies with Promoted Precipitated Iron Fischer- Tropsch Catalysts written by Rama Krishna Manne and published by . This book was released on 1991 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book TECHNOLOGY DEVELOPMENT FOR IRON AND COBALT FISCHER-TROPSCH CATALYSTS. written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The impact of activation procedure on the phase composition of precipitated iron Fischer-Tropsch (FT) catalysts has been studied. Catalyst samples taken during activation and FT synthesis have been characterized by Moessbauer spectroscopy. Formation of iron carbide is necessary for high FT activity. Hydrogen activation of precipitated iron catalysts results in reduction to predominantly metallic iron and Fe[sub 3]O[sub 4]. Metallic iron is not stable under FT 3 4 conditions and is rapidly converted to[epsilon][prime]-Fe[sub 2.2]C. Activation with carbon monoxide or syngas 2.2 with low hydrogen partial pressure reduces catalysts to[chi]-Fe[sub 5]C[sub 2] and a small amount of 5 2 superparamagnetic carbide. Exposure to FT conditions partially oxidizes iron carbide to Fe[sub 3]O[sub 4]; however, catalysts promoted with potassium or potassium and copper maintain a constant carbide content and activity after the initial oxidation. An unpromoted iron catalyst which was activated with carbon monoxide to produce 94%[chi]-Fe[sub 5]C[sub 2], deactivated rapidly as the carbide was oxidized to Fe[sub 3]O[sub 4]. No difference in activity, stability or deactivation rate was found for[chi]-Fe[sub 5]C[sub 2] and[epsilon][prime]-Fe[sub 2.2]C.
Author : Mehul D. Shroff
Publisher :
ISBN 13 :
Total Pages : 292 pages
Book Rating : 4.:/5 (344 download)
Download or read book Activation of Precipitated Iron Fischer-Tropsch Catalysts written by Mehul D. Shroff and published by . This book was released on 1995 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanoscale Attrition During Activation of Precipitated Iron Fischer-Tropsch Catalysts: Implications for Catalyst Design written by and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : André Steynberg
Publisher : Elsevier
ISBN 13 : 0080472796
Total Pages : 722 pages
Book Rating : 4.0/5 (84 download)
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
Download or read book The Role of Catalyst Activation on the Activity and Attrition of Precipitated Iron Fischer - Tropsch Catalysts written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : William James Cannella
Publisher :
ISBN 13 :
Total Pages : 356 pages
Book Rating : 4.:/5 (29 download)
Download or read book Factors Influencing Kinetics and Product Distribution in Fischer- Tropsch Synthesis Over Iron Catalysts written by William James Cannella and published by . This book was released on 1984 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 43 pages
Book Rating : 4.:/5 (871 download)
Download or read book Technology Development for Iron Fischer-Tropsch Catalysis. Quarterly Technical Progress Report No. 4, July 1, 1995--September 30, 1995 written by and published by . This book was released on 1996 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: The affect of copper promotion on the activity and selectivity of hydrogen pretreated, precipitated iron Fischer-Tropsch catalysts was studied. Fischer-Tropsch synthesis was carried out in the slurry phase in one in one liter continuous stirred tank reactors at a space velocity of 3.lNL h−1 g−1(Fe), H2:CO = 0.7 at either 270°C or 230°C. Catalysts with atomic compositions relative to iron of 10OFe/4.4Si/l. OK and 10OFe/4.4Si/2.6Cu/l. OK were used at 270°C and catalysts with the compositions of 100Fe/4.4Si/4.2K and 10OFe/4.4Si/2.6Cu/4.2K were used at 230°C. XRD and Moessbauer spectroscopy both show that the 10OFe/4.4Si/2.6Cu/l. OK catalyst contained approximately 24% [alpha]-Fe with the remainder Fe3O4 after a 24 h pretreatment with hydrogen at 220°C. Copper promotion was found to substantially increase the activity and productivity of the catalysts. Catalysts promoted with copper reached maximum activity within 100 h of synthesis while catalysts with no copper went through an induction period. The activity of the hydrogen pretreated 10OFe/4.4Si/2.6Cu/1.0K catalyst operated at 270°C was comparable to the activity of the the 100Fe/4.4Si/l. OK catalyst after pretreatment with carbon monoxide or syngas at one atmosphere pressure. However, the activity of the hydrogen pretreated 1O0Fe/4.4Si/2.6Cu/4.2K catalyst at 230°C was found to be substantially lower than the same catalyst pretreated with carbon monoxide or syngas at one atmosphere pressure.
Author :
Publisher :
ISBN 13 :
Total Pages : 31 pages
Book Rating : 4.:/5 (684 download)
Download or read book Development of Precipitated Iron Fischer-Tropsch Catalysts written by and published by . This book was released on 1997 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Four (alumina or silica) supported catalysts were prepared by conventional impregnation of two commercial supports (silica - Davison grade 952; and alumina - Vista B). Nominal compositions (on mass basis) of synthesized catalysts are: (1) 100 Fe/5 Cu/6 K/139 SiO2 (2) 100 Fe/10 Cu/6 K/134 SiO2, (3) 100 Fe/5 Cu/6 K/139 Al203 and (4) 100 Fe/10 Cu/6 K/134 Al203. The corresponding weight % of iron (as metal) in the prepared catalysts is about 33.8%. Reduction behavior of the four supported catalysts was studied by both temperature programmed and isothermal reduction in hydrogen, and by isothermal reduction in CO at 280°C. Also, two precipitated promoted iron catalysts containing aluminum oxide as a binder, were reduced isothermally in the TGA unit with hydrogen at 240°C and 280°C. One of the two alumina containing catalysts (100 Fe/5 Cu/4.2 K/20 Al203) was tested in a slurry reactor (run SA-0097), and catalyst samples withdrawn from the reactor at various times on stream were characterized by XRD to determine bulk iron phases in the catalyst. Two slurry reactor tests were completed during this quarter. The first test (SA-0097) was conducted with alumina containing catalyst with nominal composition 100 Fe/5 Cu/4.2 K/20 Al203, which was synthesized previously in our laboratory (DOE Contract DE-AC22-85PC8001 1). The second test (SB-0627) was conducted with one of the silica supported catalysts which was prepared during this quarter: 100 Fe/5 Cu/6 K/139 SiO2 (Davison silica, grade 952). The performance of these two catalysts was inferior in comparison to our catalysts B (100 Fe/5 Cu/6 K/24 SiO2) and C (100 Fe/3 Cu/4 K/16 SiO2). Activity of these two catalysts was lower, catalyst deactivation rate was faster, and gaseous hydrocarbon selectivities were higher in comparison to the baseline catalysts B and C.
Author : Samantha Harding
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (89 download)
Download or read book The effect of CO{208} on the activation of a precipitated Iron Fischer-Tropsch catalyst written by Samantha Harding and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atomic-Scale Design of Iron Fischer-Tropsch Catalysts; A Combined Computational Chemistry, Experimental, and Microkinetic Modeling Approach written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work focuses on (1) searching/summarizing published Fischer-Tropsch synthesis (FTS) mechanistic and kinetic studies of FTS reactions on iron catalysts; (2) preparation and characterization of unsupported iron catalysts with/without potassium/platinum promoters; (3) measurement of H2 and CO adsorption/dissociation kinetics on iron catalysts using transient methods; (3) analysis of the transient rate data to calculate kinetic parameters of early elementary steps in FTS; (4) construction of a microkinetic model of FTS on iron, and (5) validation of the model from collection of steady-state rate data for FTS on iron catalysts. Three unsupported iron catalysts and three alumina-supported iron catalysts were prepared by non-aqueous-evaporative deposition (NED) or aqueous impregnation (AI) and characterized by chemisorption, BET, temperature-programmed reduction (TPR), extent-of-reduction, XRD, and TEM methods. These catalysts, covering a wide range of dispersions and metal loadings, are well-reduced and relatively thermally stable up to 500-600 C in H2 and thus ideal for kinetic and mechanistic studies. Kinetic parameters for CO adsorption, CO dissociation, and surface carbon hydrogenation on these catalysts were determined from temperature-programmed desorption (TPD) of CO and temperature programmed surface hydrogenation (TPSR), temperature-programmed hydrogenation (TPH), and isothermal, transient hydrogenation (ITH). A microkinetic model was constructed for the early steps in FTS on polycrystalline iron from the kinetic parameters of elementary steps determined experimentally in this work and from literature values. Steady-state rate data were collected in a Berty reactor and used for validation of the microkinetic model. These rate data were fitted to 'smart' Langmuir-Hinshelwood rate expressions derived from a sequence of elementary steps and using a combination of fitted steady-state parameters and parameters specified from the transient measurements. The results provide a platform for further development of microkinetic models of FTS on Fe and a basis for more precise modeling of FTS activity of Fe catalysts. Calculations using periodic, self-consistent Density Functional Theory (DFT) methods were performed on various realistic models of industrial, Fe-based FTS catalysts. Close-packed, most stable Fe(110) facet was analyzed and subsequently carbide formation was found to be facile leading to the choice of the FeC(110) model representing a Fe facet with a sub-surface C atom. The Pt adatom (Fe{sup Pt}(110)) was found to be the most stable model for our studies into Pt promotion and finally the role of steps was elucidated by recourse to the defected Fe(211) facet. Binding Energies(BEs), preferred adsorption sites and geometries for all FTS relevant stable species and intermediates were evaluated on each model catalyst facet. A mechanistic model (comprising of 32 elementary steps involving 19 species) was constructed and each elementary step therein was fully characterized with respect to its thermochemistry and kinetics. Kinetic calculations involved evaluation of the Minimum Energy Pathways (MEPs) and activation energies (barriers) for each step. Vibrational frequencies were evaluated for the preferred adsorption configuration of each species with the aim of evaluating entropy-changes, pre exponential factors and serving as a useful connection with experimental surface science techniques. Comparative analysis among these four facets revealed important trends in their relative behavior and roles in FTS catalysis. Overall the First Principles Calculations afforded us a new insight into FTS catalysis on Fe and modified-Fe catalysts.
Author :
Publisher :
ISBN 13 :
Total Pages : 125 pages
Book Rating : 4.:/5 (684 download)
Download or read book TECHNOLOGY DEVELOPMENT FOR IRON AND CONBALT FISCHER-TROPSCH CATALYSTS. written by and published by . This book was released on 2000 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of alkali promoters has been widely practiced. However, data to compare various promoters is limited for the iron-based catalysts and much of the available data were obtained at low pressure or under a variety of reaction conditions. The importance of the alkali promoter in determining catalytic activity, stability and selectivity merits a comparison of the promoters under suitable reaction conditions. The present study utilizes medium pressure synthesis conditions to compare the alkali promoters under the same reaction conditions and over a wide range of conversion levels. Iron-based Fischer-Tropsch (FT) catalysts undergo a series of phase transformations during activation and use. Activation with carbon monoxide or syngas typically results in the conversion of Fe2O3 to Fe3O4 and ultimately to one or more carbides. During FT synthesis, iron carbides can be oxidized to Fe3O4 if the H2O/H2 or CO2/CO ratios are high enough. There has been considerable debate about the active phase of the FT synthesis. Some studies have indicated an active oxide species while most have supported a carbide species. Moessbauer spectroscopy has proven to be an effective technique for the analysis of iron-based FT catalysts. In situ Moessbauer studies have been reported; however, these studies have been performed at low pressure and low conversions. Studies performed at industrially relevant conditions have generally involved removing the catalyst from the reactor followed by passivation which, if not performed properly, will oxidize the catalyst. Herein are reported the Moessbauer results obtained on an unpromoted precipitated iron catalyst that was activated and reacted in a slurry phase, continuous stirred tank reactor at high conversion and under industrially relevant conditions.
Author : A. Parmaliana
Publisher : Elsevier
ISBN 13 : 0080537308
Total Pages : 1005 pages
Book Rating : 4.0/5 (85 download)
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.
Author : Wilson D. Shafer
Publisher : MDPI
ISBN 13 : 303928388X
Total Pages : 414 pages
Book Rating : 4.0/5 (392 download)
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.
Author : Ronald Alan Dictor
Publisher :
ISBN 13 :
Total Pages : 600 pages
Book Rating : 4.:/5 (29 download)
Download or read book Study of Fischer-Tropsch Synthesis Over Iron-based Catalysts Using a Well-stirred Slurry Reactor written by Ronald Alan Dictor and published by . This book was released on 1984 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 16 pages
Book Rating : 4.:/5 (683 download)
Download or read book Technology Development for Iron Fischer-Tropsch Catalysis. Quarterly Technical Progress Report, October--December, 1994 written by and published by . This book was released on 1994 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fischer-Tropsch catalysts must undergo a pretreatment in order to be active. As part of the authors comprehensive study to maximize the activity of iron based precipitated Fischer-Tropsch catalysts, they are currently attempting to optimize the activation procedure. Although they are able to achieve high activity using CO pretreatment, the catalysts tend to deactivate suddenly and rapidly after 500 hr of synthesis. Kolbel reports high CO conversion comparable to these results at a lower gas flow (2.4 vs. 3.4 nL/hr-g(Fe)); however, he achieved greater stability with conversions reported to be 90% after 1,400 hrs. One possibility for Kolbel's higher stability could be due to the activation procedure. Herein are reported the initial results of a study to optimize the catalyst composition and the operating conditions for the iron based slurry phase Fischer-Tropsch synthesis when synthesis gas activation is utilized.
Author : Amitava Sarkar
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (129 download)
Download or read book Characterization of Active Species in Rb Promoted Iron Catalyst During Fischer-Tropsch Synthesis written by Amitava Sarkar and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
