Fischer-Tropsch Synthesis: Kinetics and Effect of Water for a Co/Al2O3 Catalyst

Das, Tapan K.; Zhan, Xiaodong; Li, Jinlin; Jacobs, Gary; Dry, Mark E.; Davis, Burtron H.

doi:10.1016/s0167-2991(07)80484-8

Cited by 26 publications

(20 citation statements)

References 28 publications

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“…Also, in 2010, Zhou et al [51], confirmed the findings and the proposed rate equation by Botes et al [50]. Review articles concerning cobalt-catalyzed F-T kinetics are available in the literature [52,53], whereas Zennaro et al [54] and Das et al [55] presented in a tabulated format the explicit rate equations, which were suggested for cobalt catalyst. Of these, the LHHW type rate equations proposed by Outi et al [56], Sarup and Wojciechowski [57] and Yates and Satterfield [58] had been frequently cited in the literature [59].…”

Section: Chang Et Al []mentioning

confidence: 72%

Fischer–Tropsch Synthesis in Slurry Bubble Column Reactors: Experimental Investigations and Modeling – A Review

Basha

Sehabiague

Abdel‐Wahab

et al. 2015

International Journal of Chemical Reactor Engineering

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This paper presents an extensive review of the kinetics, hydrodynamics, mass transfer, heat transfer and mathematical as well as computational fluid dynamics (CFD) modeling of Low-Temperature Tropsch Synthesis (LTFT) synthesis in Slurry Bubble Column Reactors (SBCRs), with the aim of identifying potential research and development areas in this particular field. The kinetic expressions developed for F-T synthesis over iron and cobalt catalysts along with the water gas shift (WGS) reactions are summarized and compared. The experimental data and empirical correlations to predict the hydrodynamics (gas holdup, Sauter mean bubble diameter, and bubble rise velocity), mass transfer coefficients and heat transfer coefficients are presented. The effects of various operating variables, including pressure, temperature, gas velocity, catalyst concentration, reactor geometry, and reactor internals on the hydrodynamic and transport parameters as well as the performance of SBCRs are discussed. Additionally, modeling efforts of SBCRs, using axial dispersion models (ADM), multiple cell recirculation models (MCCM) and computational fluid dynamics (CFD), are addressed. This review revealed the following:(1) Numerous F-T and WGS kinetic rate expressions are available for cobalt and iron catalysts and one must be careful in selecting the appropriate expressions for LTFT. Iron catalyst suffers from severe attrition and subsequent deactivation in SBCRs and accordingly building a costly catalyst manufacturing facility onsite is required to maintain a steady operation of the F-T reactor;(2) Experimental data on the hydrodynamic and transport parameters at high pressures and temperatures, typical to those of actual F-T synthesis, remain scanty when compared with the plethora of studies conducted using air-water systems in small reactors at ambient conditions; (3) Several empirical correlations for predicting the hydrodynamic and mass as well heat transfer parameters are available and one should select those which consider the reactor diameter, gas mixtures and the potential foamability of the F-T liquids; (4) The effect of cooling internals configuration and sparger design on the hydrodynamic and transport parameters, local turbulence, mixing and catalyst attrition are yet to be seriously addressed; (5) The impact of operating variables on the hydrodynamic and transport parameters as well as the overall performance of the SBCRs should be investigated using actual F-T fluid-solid systems under typical pressures and temperatures using a large-scale reactor ( > 0.15 m ID) in the presence of gas spargers and cooling internals; (6) Significant efforts are still required in order to advance CFD modeling of SBCRs, particularly those pertaining to the relevant closure models, such as drag, lift and turbulence. Also, cooling internals configuration and the design as well as orientation of gas spargers should be accounted for in the CFD modeling; and (7) Proper validations of the CFD formulations using actual systems for F-T SBCR are needed.

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Section: Chang Et Al []mentioning

confidence: 72%

Fischer–Tropsch Synthesis in Slurry Bubble Column Reactors: Experimental Investigations and Modeling – A Review

Basha

Sehabiague

Abdel‐Wahab

et al. 2015

International Journal of Chemical Reactor Engineering

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“…For low conversion plug flow rectors (Fixed bed) the following equation was used to obtain the experimental reaction rate value [72,73]:…”

Section: Kinetic Data Gatheringmentioning

confidence: 99%

Generalized kinetic model for iron and cobalt based Fischer–Tropsch synthesis catalysts: Review and model evaluation

Mousavi

Zamaniyan

Irani

et al. 2015

Applied Catalysis A: General

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“…The experimental data of this study were fitted by a power-law expression. Das et al [21] investigated the kinetics and effects of water for a 12.4 wt % Co/SiO 2 catalyst using a 1-L continuously stirred tank reactor (CSTR). The measured data of this study were also fitted by a power-law expression.…”

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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Fischer-Tropsch Synthesis: Kinetics and Effect of Water for a Co/Al2O3 Catalyst

Cited by 26 publications

References 28 publications

Fischer–Tropsch Synthesis in Slurry Bubble Column Reactors: Experimental Investigations and Modeling – A Review

Fischer–Tropsch Synthesis in Slurry Bubble Column Reactors: Experimental Investigations and Modeling – A Review

Generalized kinetic model for iron and cobalt based Fischer–Tropsch synthesis catalysts: Review and model evaluation

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

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