Kinetics of CO + H2 Reaction over Co-Cu-Al2O3 Catalyst

Yang, Chen-Hsyong; Massoth, F.E.; Oblad, A.G.

doi:10.1021/ba-1979-0178.ch005

Cited by 37 publications

(28 citation statements)

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“…The explicit rate equations have been developed based on the Langmuir–Hinshelwood–Hougen–Watson (LHHW) adsorption theory over Co‐ and Fe‐based FTS catalysts . For the determination of kinetic models, three certain mechanisms are proposed on the basis of various monomer formation (elementary reactions) and carbon chain distribution pathways.…”

Section: Resultsmentioning

confidence: 99%

“…According to the different surface reaction mechanisms and rate determination steps over cobalt‐based catalysts, various forms of kinetic expressions are obtained. A number of kinetic studies of FTS over cobalt catalysts have been performed where the expressions were fitted on the carbon monoxide rate . For example, Rautavuoma and van der Baan studied the rate of reaction at atmospheric pressure, 250°C, and conversions below 2%, and their fitted equation was

- r_{CO} = \frac{a P_{H_{2}} P_{CO}^{1 / 2}}{{(1 + b P_{CO}^{1 / 2})}^{3}}

.…”

Section: Resultsmentioning

confidence: 99%

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Modification of Co/Al₂ O₃ Fischer-Tropsch Nanocatalysts by Adding Ni: A Kinetic Approach

Nikparsa

Mirzaei

Rauch

2016

Int. J. Chem. Kinet.

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In this article, the effects of Ni (Co:Ni ratio = 4:1) on the performances and kinetic parameters of Co/Al2O3 nanocatalysts are explored in Fischer–Tropsch synthesis. As a result, the probability of chain growth increases and the deactivation rate decreases with addition of Ni. The properties of catalysts are characterized at different stages using Brunauer–Emmett–Teller analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and the vibrating sample magnetometer technique. The Co/Ni/Al2O3 catalyst with higher surface area and pore size exhibits higher activity and C5+ selectivity. The different results obtained for room‐temperature ferromagnetism have been attributed to the different metal oxides in the catalysts. The Fischer Tropsch kinetic study is done on the basis of the Langmuir–Hinshelwood–Hougen–Watson adsorption theory. Seven kinetic expressions based on the carbide and enolic mechanisms are selected. All experimental data are theoretically examined with these kinetic expressions to derive the best kinetic according to the linear and nonlinear approaches. The kinetic parameters of the fitted model, including the rate constant (k) and activation energy (Ea), are calculated with the Levenberg–Marquardt and genetic algorithm. The results show that by adding Ni the activation energy (Ea) decreases, the reaction rate (–RCO) increases, and the CO adsorption on the Co/Ni/Al2O3 catalyst is faster as well.

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Section: Resultsmentioning

confidence: 99%

- r_{CO} = \frac{a P_{H_{2}} P_{CO}^{1 / 2}}{{(1 + b P_{CO}^{1 / 2})}^{3}}

.…”

Section: Resultsmentioning

confidence: 99%

Modification of Co/Al₂ O₃ Fischer-Tropsch Nanocatalysts by Adding Ni: A Kinetic Approach

Nikparsa

Mirzaei

Rauch

2016

Int. J. Chem. Kinet.

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“…A summary of these studies; the type of rector and catalyst used; operating conditions i.e. temperature, pressure and H 2 /CO molar ratio; as well as the proposed rate equation; are given in Table 1 in the order of publication date [7][8][9][10][11][12][13][14][15][16][17][18][19]. In other studies the rate of FT synthesis reactions was expressed based on a proposed mechanism with a postulated rate deterring step (RDS).…”

Section: Introductionmentioning

confidence: 99%

A comprehensive study of kinetics mechanism of Fischer-Tropsch synthesis over cobalt-based catalyst

Wyszyński

Rahbar

Tsolakis

et al. 2017

Chemical Engineering Science

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Link to publication on Research at Birmingham portal General rights Unless a licence is specified above, all rights (including copyright and moral rights) in this document are retained by the authors and/or the copyright holders. The express permission of the copyright holder must be obtained for any use of this material other than for purposes permitted by law. • Users may freely distribute the URL that is used to identify this publication. • Users may download and/or print one copy of the publication from the University of Birmingham research portal for the purpose of private study or non-commercial research. • User may use extracts from the document in line with the concept of 'fair dealing' under the Copyright, Designs and Patents Act 1988 (?) • Users may not further distribute the material nor use it for the purposes of commercial gain. Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.

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“…There are a number of kinetic studies that were carried out empirically to fit the data based on the powerlaw rate mechanism. Yang et al [18] and Wang [19] found empirical rate expressions for supported Co catalysts using a fixed bed reactor via regression of a power-law equation. Zennaro et al [20] studied the kinetics on a well-characterized 11.7% Co/TiO 2 catalyst in a differential fixed bed reactor.…”

Section: Introductionmentioning

confidence: 99%

Catalytic performance of cobalt–silica catalyst for Fischer–Tropsch synthesis: Effects of reaction rates on efficiency of liquid synthesis

Moazami

Mahmoudi

Rahbar

et al. 2015

Chemical Engineering Science

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A one-dimensional pseudo-homogeneous mathematical model of a fixed bed reactor for Fischer-Tropsch (FT) synthesis was developed for the flow of simulated N 2 -rich syngas over an in-house cobalt-silica catalyst. This study aims at improving the efficiency of FT synthesis by maximizing the liquid productivities and selectivity, as well as maximizing the syngas conversion and minimizing the methane formation. The developed model predicts the fraction of the reactants and products along the reactor bed length. The rate of syngas conversion and the rate of CO 2 , H 2 O, CH 4 , C 2 H 4 , C 2 H 6 , C 3 H 8 , n-C 4 H 10 , i-C 4 H 10 and C 6.05 H 12.36 (C 5+ ) formation were calculated by developing advanced codes in MATLAB. The reaction equations were proposed as a number of lumped chemical reactions (8 reactions, including water gas shift reaction) by means of the molar coefficients of reaction molecules (11 reactive species). The kinetic parameters were estimated by global optimization in MATLAB using the global search method. Optimum values were achieved during the search process. The results predicted by the model were in very good agreement with those measured experimentally at different operating conditions, with respect to conversion and the FT products' selectivity. The rates of production and consumption were derived from a modified power-law rate expression. This study shows that the adapted rate model can deliver a better prediction of final conversion and selectivity. The accuracy of the fitted model relative to the experimental data was determined by a quantitative analysis method using the mean absolute relative residual percentage (MARR %) for the total of 35 data points. It was found that the model based on the modified equation provided a better fit to the experimental data with a MARR of 6.57%, compared to the classic equation with a MARR of 12.24%.The model predicts the influence of reaction rates on the performance of the fixed bed FT reactor using an unpromoted Co/SiO 2 catalyst at 503 K, 15 bar and 6 L g cat -1 h -1 . As a result, the conversions of 91.57 and 97.26% were achieved for CO and H 2 , respectively with the FT C 5+ synthesis reaction rate of 7.81×10 -5 mol g cat -1 s -1 . The higher rate of C 5+ formation was found by increasing FT reaction rates compared to the rate of lighter the hydrocarbons' formation. At the same condition, only 5.04 and 8.91% methane and C 2 -C 4 selectivity respectively, were predicted; while the highest value of 86.05% liquid (C 5+ ) selectivity was obtained in this case. It was concluded that the higher rate of conversion of H 2 inside the pores filled with liquid products, compared to that of CO, caused an increase in the H 2 /CO ratio in the catalyst pores; and thus, a shift towards the formation of lighter hydrocarbons.

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Kinetics of CO + H₂ Reaction over Co-Cu-Al₂O₃ Catalyst

Cited by 37 publications

References 0 publications

Modification of Co/Al₂ O₃ Fischer-Tropsch Nanocatalysts by Adding Ni: A Kinetic Approach

Modification of Co/Al₂ O₃ Fischer-Tropsch Nanocatalysts by Adding Ni: A Kinetic Approach

A comprehensive study of kinetics mechanism of Fischer-Tropsch synthesis over cobalt-based catalyst

Catalytic performance of cobalt–silica catalyst for Fischer–Tropsch synthesis: Effects of reaction rates on efficiency of liquid synthesis

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Kinetics of CO + H2 Reaction over Co-Cu-Al2O3 Catalyst

Cited by 37 publications

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Modification of Co/Al2 O3 Fischer-Tropsch Nanocatalysts by Adding Ni: A Kinetic Approach

Modification of Co/Al2 O3 Fischer-Tropsch Nanocatalysts by Adding Ni: A Kinetic Approach

A comprehensive study of kinetics mechanism of Fischer-Tropsch synthesis over cobalt-based catalyst

Catalytic performance of cobalt–silica catalyst for Fischer–Tropsch synthesis: Effects of reaction rates on efficiency of liquid synthesis

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Kinetics of CO + H₂ Reaction over Co-Cu-Al₂O₃ Catalyst

Modification of Co/Al₂ O₃ Fischer-Tropsch Nanocatalysts by Adding Ni: A Kinetic Approach

Modification of Co/Al₂ O₃ Fischer-Tropsch Nanocatalysts by Adding Ni: A Kinetic Approach