CO Adsorption on Fe4C (100), (110), and (111) Surfaces in Fischer−Tropsch Synthesis

2008 ◽  
Vol 112 (48) ◽  
pp. 19018-19029 ◽  
Author(s):  
Chun-Mei Deng ◽  
Chun-Fang Huo ◽  
Li-Li Bao ◽  
Gang Feng ◽  
Yong-Wang Li ◽  
...  
Keyword(s):  
Co Adsorption ◽  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis

scholarly journals Theoretical Study of CO Adsorption and Activation on Orthorhombic Fe7C3(001) Surfaces for Fischer–Tropsch Synthesis Using Density Functional Theory Calculations

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 563
Author(s):  
Hee-Joon Chun ◽  
Yong Tae Kim
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Co Adsorption ◽  
Density Functional Theory Calculations ◽  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Functional Theory ◽  
Fischer Tropsch Synthesis ◽  
Co Dissociation ◽  
Co Activation

Fischer–Tropsch synthesis (FTS), which converts CO and H2 into useful hydrocarbon products, has attracted considerable attention as an efficient method to replace crude oil resources. Fe-based catalysts are mainly used in industrial FTS, and Fe7C3 is a common carbide phase in the FTS reaction. However, the intrinsic catalytic properties of Fe7C3 are theoretically unknown. Therefore, as a first attempt to understand the FTS reaction on Fe7C3, direct CO* dissociation on orthorhombic Fe7C3(001) (o-Fe7C3(001)) surfaces was studied using density functional theory (DFT) calculations. The surface energies of 14 terminations of o-Fe7C3(001) were first compared, and the results showed that (001)0.20 was the most thermodynamically stable termination. Furthermore, to understand the effect of the surface C atom coverage on CO* activation, C–O bond dissociation was performed on the o-Fe7C3(001)0.85, (001)0.13, (001)0.20, (001)0.09, and (001)0.99 surfaces, where the surface C atom coverages were 0.00, 0.17, 0.33, 0.33, and 0.60, respectively. The results showed that the CO* activation linearly decreased as the surface C atom coverage increased. Therefore, it can be concluded that the thermodynamic and kinetic selectivity toward direct CO* dissociation increased when the o-Fe7C3(001) surface had more C* vacancies.

scholarly journals Lump Kinetic Analysis of Syngas Composition Effect on Fischer-Tropsch Synthesis over Cobalt and Cobalt-Rhenium Alumina Supported Catalyst

2016 ◽  
Vol 11 (1) ◽  
pp. 84
Author(s):  
Dewi Tristantini ◽  
Ricky Kristanda Suwignjo
Keyword(s):  
Kinetic Analysis ◽  
Kinetic Constant ◽  
Co Adsorption ◽  
Supported Catalyst ◽  
Tropsch Synthesis ◽  
Molar Ratio ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Adsorption Step ◽  
Reactant Conversion

<p>This study investigated lump kinetic analysis of Fischer-Tropsch synthesis over Cobalt and Cobalt-Rhenium Alumina supported catalyst (Co/γ-Al<sub>2</sub>O<sub>3</sub> and Co-Re/γ-Al<sub>2</sub>O<sub>3</sub>) at 20 bars and 483 K using feed gas with molar H<sub>2</sub>/CO ratios of 1.0 to 2.1. Syngas with H<sub>2</sub>/CO molar ratio of 1.0 represents syngas characteristic derived from biomass, while the 2.1 molar ratio syngas derived from coal. Rhenium was used as the promoter for the cobalt catalyst. Isothermal Langmuir adsorption mechanism was used to build kinetic model. Existing kinetic model of Fischer-Tropsch synthesis over cobalt alumina supported catalysts only valid for operating pressure less than 10 bar. CO insertion mechanism with hydrogenation step of catalyst-adsorbed CO by catalyst-adsorbed H component as the rate-limiting step is valid for operating condition in this research. Higher H<sub>2</sub>/CO ratio makes faster hydrogenation step and less-product dominated in the associative CO adsorption step and dissociative H<sub>2</sub> adsorption equilibrium step. Kinetic constant for hydrogenation step increases 73-421% in syngas with 2.1 H<sub>2</sub>/CO molar ratio compared to condition with 1.0 H<sub>2</sub>/CO molar ratio. Faster hydrogenation step (with higher kinetic constant) results in higher reactant conversion. Equilibrium constant for associative CO adsorption and dissociative H<sub>2</sub> adsorption step decreases 53-94% and 13-82%, respectively, in syngas with higher H<sub>2</sub>/CO molar ratio. Less product dominated reactant adsorption step (lower equilibrium constant for CO and H<sub>2</sub> adsorption step) gives higher CH<sub>4</sub> product selectivity, which occurred on 2.1 molar ratio of syngas. Rhenium (Re) metal on cobalt catalyst with composition 0.05%Re-12%Co/γ-Al<sub>2</sub>O<sub>3</sub> only gives effect as structural promoter, which only increases reactant conversion with the same product selectivity. Copyright © 2016 BCREC GROUP. All rights reserved</p><p class="HistoryArticleBCREC"><em>Received: 10<sup>th</sup> November 2015; Revised: 10<sup>th</sup> February 2016; Accepted: 16<sup>th</sup> February 2016</em></p><p><strong>How to Cite</strong>: Tristantini, D., Suwignjo, R.K. (2016). Lump Kinetic Analysis of Syngas Composition Effect on Fischer-Tropsch Synthesis over Cobalt and Cobalt-Rhenium Alumina Supported Catalyst.<em> Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11 (1): 84-92. (doi:10.9767/bcrec.11.1.424.84-92)</p><p><strong>Permalink/DOI</strong>: <a href="http://dx.doi.org/10.9767/bcrec.11.1.424.84-92">http://dx.doi.org/10.9767/bcrec.11.1.424.84-92</a></p>

Study of the Performance of the Cobalt Based Catalyst on Different Supports for Fischer-Tropsch Synthesis

2014 ◽  
Vol 881-883 ◽  
pp. 251-255 ◽  
Author(s):  
Wan Li Ye
Keyword(s):  
Catalytic Activity ◽  
Pore Structure ◽  
Co Adsorption ◽  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Hydrocarbon Production ◽  
Fischer Tropsch Synthesis ◽  
Heavy Hydrocarbon ◽  
Large Pore ◽  
Methane Selectivity

With cobalt-based catalyst loaded by Al2O3, TiO2 and ZrO2 as research objectives, in this paper, the performance of these cobalt-based catalysts in Fischer-Tropsch synthesis is discussed. Besides, BET, XRD, FTIR, TPR superficial characteristics and evaluation experiments have been carried out for these catalysts respectively, and the result shows that, the catalyst loaded by ZrO2 has the highest catalytic activity, while the catalyst loaded by Al2O3 has the lowest catalytic activity. The catalyst with higher CO adsorption and dissolving capacity has higher activity; meanwhile, the higher reducibility the catalyst has, the higher the activity of the catalyst will be. In addition, catalyst methane selectivity loaded by Al2O3 is the highest, while catalyst methane selectivity loaded by TiO2 is the lowest, which shows that the large pore structure of catalyst is good for heavy hydrocarbon production, meanwhile, formate species generated on the surface of catalyst implies that the formate species is involved in the generation of methane. Keywords.Carrier; cobalt-based catalyst; Fischer-Tropsch synthesis; performance

The Development of Cobalt-Based Catalysts for Fischer-Tropsch Synthesis

2010 ◽  
Vol 31 (8) ◽  
pp. 919-927 ◽  
Author(s):  
Yuhan SUN ◽  
Jiangang CHEN ◽  
Jungang WANG ◽  
Litao JIA ◽  
Bo HOU ◽  
...  
Keyword(s):  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis
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