Author: Magdalena Maria Hauman HaumanPublisher:
ISBN:
Category :
Languages : en
Pages : 240
Book Description
Fundamental Understanding of Re-dispersion of Cobalt on Supported Model Fischer-Tropsch Catalysts
Author: Magdalena Maria Hauman HaumanPublisher:
ISBN:
Category :
Languages : en
Pages : 240
Book Description
Fundamental Understanding of Cobalt Fischer-Tropsch Synthesis Catalyst Deactivation
Author: D. KistamurthyPublisher:
ISBN: 9789038638539
Category :
Languages : en
Pages : 218
Book Description
Advances in Fischer-Tropsch Synthesis, Catalysts, and Catalysis
Author: B. H. DavisPublisher: 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
Understanding Noble Metal Addition in Cobalt Fischer Tropsch Catalysts
Author: Kari Marie CookPublisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 188
Book Description
The effects of noble metal (NM) promotion and deposition order (co-deposition of NM with the final Co deposition [co-dep] or sequential deposition of NM after Co deposition [seq-dep]) on surface area, pore size, metal retention, crystallite size, noble metal distribution and bonding in Co Fischer Tropsch (FT) catalysts were studied as were the resulting Co reducibility and Fischer Tropsch activity/selectivity properties. Catalysts containing nominally 25wt% Co with either 0.3 wt% Ru, 0.58 wt% Pt, 0.55wt% Re, or no NM on a La-stabilized-Al2O3 support were prepared by wet deposition. The Co, Pt, and Re were uniformly dispersed, but Ru distribution and retention were problematic and deposition-order dependent--85% was lost with co-dep, but it was uniformly distributed while 54% was lost with seq-dep and it was concentrated at the pellet edge. The co-dep catalysts all have smaller reduced Co crystallite size than their corresponding seq-dep catalysts. The average crystallite diameters for all 3 co-dep catalysts are between 4.1 and 4.3nm and ~90% of the crystallites are 6nm. XAFS measurements showed that after reduction at 360oC, Pt is bonded with Co even with mild calcination between the final Co and the Pt deposition. On the other hand, neither Ru nor Re formed direct bonds with Co. Ru remained in a separate metal phase after reduction even at low loadings. Re remained as Re2O7 and still promoted Co reduction well (e.g. 42% reduced to Co metal compared to none for the unpromoted catalyst). By all measures of reducibility (TPR, EOR, H2 uptake), all NM promoted catalysts were more reducible than the unpromoted catalyst. The co-dep catalysts have lower TPR peak temperatures, but lower extents of reduction than their corresponding seq-dep catalysts. The NM type effect on overall extent of reduction trend was Co/Pt-seqCo/Re-seq>Co/Ru-seq=Co/Pt-co>Co/Re-co>Co/Ru-co>Co. The Co/Pt-co catalyst was the most active of all the catalysts both on rate per mass and per site basis. The co-dep catalysts were all more active than the corresponding sequentially deposited catalysts. The co-dep Pt and Re catalyst activity is greater due to higher activity per site, while co-dep Ru activity is greater due to a higher abundance of active sites.
Fischer-Tropsch Cobalt Catalyst Improvements with the Presence of TiO2, La2O3, and ZrO2 on an Alumina Support
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781719501361
Category :
Languages : en
Pages : 100
Book Description
The objective of this study was to evaluate the effect of titanium oxide, lanthanum oxide, and zirconium oxide on alumina supported cobalt catalysts. The hypothesis was that the presence of lanthanum oxide, titanium oxide, and zirconium oxide would reduce the interaction between cobalt and the alumina support. This was of interest because an optimized weakened interaction could lead to the most advantageous cobalt dispersion, particle size, and reducibility. The presence of these oxides on the support were investigated using a wide range of characterization techniques such as SEM, nitrogen adsorption, x-ray diffraction (XRD), temperature programmed reduction (TPR), temperature programmed reduction after reduction (TPR-AR), and hydrogen chemisorptions/pulse reoxidation. Results indicated that both La2O3 and TiO2 doped supports facilitated the reduction of cobalt oxide species in reference to pure alumina supported cobalt catalysts, however further investigation is needed to determine the effect of ZrO2 on the reduction profile. Results showed an increased corrected cluster size for all three doped supported catalysts in comparison to their reference catalysts. The increase in reduction and an increase in the cluster size led to the conclusion that the support-metal interaction weakened by the addition of TiO2 and La2O3. It is also likely that the interaction decreased upon presence of ZrO2 on the alumina, but further research is necessary. Preliminary results have indicated that the alumina-supported catalysts with titanium oxide and lanthanum oxide present are of interest because of the weakened cobalt support interaction. These catalysts showed an increased extent of reduction, therefore more metallic cobalt is present on the support. However, whether or not there is more cobalt available to participate in the Fischer-Tropsch synthesis reaction (cobalt surface atoms) depends also on the cluster size. On one hand, increasing cluster size alone tends to decrease the
Bench-scale Studies of the Fischer-Tropsch Synthesis Over Iron, Nickel, and Nickel Cobalt Catalysts (Japan)
Author: Shiro WatanabePublisher:
ISBN:
Category : Fischer-Tropsch process
Languages : en
Pages : 48
Book Description
Nano-carbon Supported Cobalt Catalysts in Fischer-Tropsch Synthesis
Author: Amadeus RosePublisher:
ISBN: 9783844027860
Category :
Languages : en
Pages : 202
Book Description
Development of a Stable Cobalt-ruthenium Fischer-Tropsch Catalyst
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 42
Book Description
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.
Iron and Cobalt Catalysts
Author: Wilson D. ShaferPublisher: 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: