Intrinsic kinetics of Fischer–Tropsch reactions over an industrial Co–Ru/γ-Al2O3 catalyst in slurry phase reactor

Sari, Ataallah; Zamani, Yahya; Taheri, Sayyed Ali

doi:10.1016/j.fuproc.2009.06.024

Cited by 60 publications

(22 citation statements)

References 25 publications

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“…Indeed, increasing the FTS reaction temperature increases the mobility of hydrogen on the catalyst surface which leads, among several other effects, to higher % CO conversion. These results are also similar to what is normally observed for the Co-Ru FTS catalysts (Tavasoli et al, 2005;Sari et al, 2009;Trépanier et al, 2009b). Table 3 shows the influence of pressure and temperature on the FTS turnover rate (g HC /g −1 cat h −1 ) and the chain growth probability (˛) for hydrocarbons with 5-22 carbon atoms.…”

Section: Fts Catalyst Activity and Selectivitysupporting

confidence: 87%

“…Increasing the total pressure increases the rate of propagation which is consistent with the decreased selectivity of methane. The chain growth probability (˛) is high compared to similar studies on Co-based catalysts (Zennaro et al, 2000;Sari et al, 2009;Trépanier et al, 2009b). Thus, it seems that the addition of Ru and a small amount of K onto the catalyst have improved the Anderson-Schulz-Flory distribution for hydrocarbons with 5-22 carbon atoms.…”

Section: Fts Catalyst Activity and Selectivitymentioning

confidence: 82%

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Kinetics study on cnt‐supported RuKCo FTS catalyst in a fixed bed reactor

et al. 2011

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The rate of syngas (H 2 /CO) consumption over a RuKCo/CNT Fischer-Tropsch synthesis (FTS) catalyst was measured in a fixed bed microreactor at 210-225 • C, 2-3.5 MPa, H 2 /CO feed molar ratios of 1-2.5, and gas hourly space velocity (GHSV) range of 2700-3600 h −1 . The data have been used to model the kinetics of the FTS reactions within the range of the studied conditions. One empirical power law model and four semi-empirical kinetic models based on Langmuir-Hinshelwood-type equation have been evaluated. The best fitting was obtained with the equation:similar to that proposed by Brötz et al. The estimated activation energy (E = 80-85 kJ/mol) is lower than that is reported in the literature. The validity of these results are restricted to fixed beds with the given catalyst in the tested conversion regime.Le taux de consommation de gaz de synthèse (H 2 /CO) sur un catalyseur de synthèse de Fischer-Tropsch (SFT) RuKCo/CNT aété mesuré dans un microréacteurà lit fixeà 210à 225 • C, 2à 3,5 MPa, des rapports molaires d'alimentation H 2 /CO de 1à 2,5 et une portée de vitesse horaire des gaz de 2700à 3600 h −1 . Les données ontété utilisées pour modeler la cinétique des réactions de la SFT au sein de la portée des conditionsétudiées. Un modèle de loi exponentielle empirique et quatre modèles cinétiques semi-empiriques fondés sur uneéquation de type Langmuir-Hinshelwood ontétéévalués. Ce qui correspondait le mieuxétait obtenu avec l'équation suivante:(1 + 7.2 × 10 −2 P 0.72semblableà celle proposée par Brötz et coll. L'énergie d'activation estimée (E = 80-85 KJ/mol) est inférieureà celle rapportée par la littérature. Ces résultats sont associés aux propriétés physiques et chimiques uniques des supports de nanotubes de carbone qui réduisent l'énergie d'activation du catalyseur.

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Section: Fts Catalyst Activity and Selectivitysupporting

confidence: 87%

Section: Fts Catalyst Activity and Selectivitymentioning

confidence: 82%

Kinetics study on cnt‐supported RuKCo FTS catalyst in a fixed bed reactor

et al. 2011

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“…Although exploring the FT mechanism is much more complex, several mechanisms have been proposed regarding the chemistry of CO as well as the chemical nature of the products formed [19,20]. Carbide and enolic mechanisms are the most popular theories proposed for the formation of monomer species [21][22][23][24][25]. The carbide mechanism assumes that hydrocarbons are produced by the hydrogenation of metal carbide, forming the methylene monomer, which is subsequently polymerized until the surface alkyl species terminate to products [19].…”

Section: Introductionmentioning

confidence: 99%

Impact of Na Promoter on Structural Properties and Catalytic Performance of CoNi/Al2O3 Nanocatalysts for the CO Hydrogenation Process: Fischer–Tropsch Technology

2015

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This work deals with the effect of adding Na to bimetallic sol-gel derived alumina supported Co/Ni nanocatalysts in Fischer-Tropsch synthesis. The catalyst activity and selectivity changed with different levels of Na, and the catalyst with 2 % Na loading was selected as an optimal catalyst to compare with un-promoted Co/Ni/ Al 2 O 3 catalyst. Na reduced the methane selectivity by increasing the chain-growth probability (a-value) at 12 bar. The results of physico-chemical characterizations show that the Na promoter plays a significant role in the catalytic structure. Additionally, the kinetic behavior was considered in absence and presence of Na over CoNi/Al 2 O 3 catalysts. We applied an enolic approach, which was developed based on the interaction between adsorption HCO and dissociated adsorption hydrogen, through the Langmuir-Hinshelwood-Hougen-Watson (LHHW) adsorption theory. Kinetic parameters, including the rate constant (k) and activation energy (E a ) of the catalysts, were also determined. The results show that, by adding Na, the activation energy (E a ) decreases and the reaction rate (-R CO ) increases. Graphical Abstract

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“…The MARR 262 values of the obtained kinetic models are presented in Table 4; as it 263 shown the FT-III model having the minimal MARR value (12.53) fits 264 the experimental data well. The comparison of the calculated and lead to the apparent energy activation of just a few kJ/mol [38]. 284 The rate determining step of the Fischer-Tropsch reaction is the 285 mass-transfer of reactants and products to the catalyst surface, 286 unlikely.…”

mentioning

confidence: 99%

“…Actually the kinetics based on 35 CO consumption attends more than another method because the 36 products of FTS are very complicated. 37 In the many publications, intrinsic reaction rate equations for 38 the FT equation (hydrocarbon forming only) based on Langmuir- 39 Hinshelwood-Hougen-Watson (LHHW) adsorption theory have 40 been developed and used successfully for iron and cobalt-based 41 catalysts [19][20][21][22][23][24][25]. The mechanisms proposed bases in approach 42 were including the carbide, enolic, and direct insertion theories.…”

mentioning

confidence: 99%