A Study on Vapour-Liquid Equilibria in Fischer-Tropsch Synthesis

11In this paper, we investigate the performance characteristics of cobalt catalyst (Co/SiO2) pellets with 12 eggshell morphology used in Fischer-Tropsch synthesis (FTS). An analytical strategy is developed first, to 13 estimate the optimum thickness of active shell. When the system is strongly mass transfer limited (Thiele 14 Modulus≫1) it can be represented by slab geometry in order to determine the shell thickness. Otherwise, 15 the analysis is done on a spherical geometry. In the latter case, the continuity equation simplifies into 16Emden-Fowler equation which was solved via numerical iterative technique based on prior investigations. 17 A more accurate detailed numerical solution was also developed for this intra-pellet model. This numerical 18 result is compared with the analytical solution as well as with a previously published model. The sensitivity 19 of the catalyst performance to temperature and pressure variations was also examined. Performance 20 analysis was carried out considering both rate of reaction and α chain growth probability as yardsticks. 21These performance parameters were examined using contour maps with Thiele modulus and H2/CO ratio 22 as their coordinates. On this map there exists an ideal combination of gas ratio and Thiele modulus that 23 fulfills the design requirements of product selectivity and high catalyst activity. This study confirms the 24 need for, and the advantage of, using egg-shell morphology for Fischer-Tropsch synthesis applications . 25 26 27 28 29 30 31 32 33

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“…37 38 During the numerical modeling, while comparing with analytical result, pre-exponential factor of Yates 39…”

Section: Performance Analysis 30mentioning

confidence: 99%

Performance Characteristics of Eggshell Co/SiO₂ Fischer–Tropsch Catalysts: A Modeling Study

Gardezi

Joseph

2015

Ind. Eng. Chem. Res.

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Section: Development Of a Generalized Reactor Modelmentioning

confidence: 99%

“…There is evidence in the literature that the cubic state equations widely used to describe the VLE of the FTS system are Soave–Redlich–Kwong (SRK) ,− and Peng–Robinson (PR). ,− Wang et al developed a modified version of the SRK equation of state to represent the gas–liquid equilibrium (solubility in heavy waxes) in the FTS, considering a wide range of solutes such as CO, H 2 , CO 2 , CH 4 , C 2 H 4 , C 2 H 6 , and heavy wax solvents from C 20 to C 61 using a wide range of temperatures and pressures. Such a SRK equation has been preferably used − because of its high predictive and descriptive ability of the gas–liquid equilibrium behavior in the FTS. Karimi et al showed a comparison between the results obtained by the SRK state equation, the PR equation as well as its modified versions, and Henry’s empirical equation for the determination of phase equilibrium in the process FTS, where it is strongly shown that the modified SRK equation agrees with the experimental data collected from the literature.…”

Section: Development Of a Generalized Reactor Modelmentioning

confidence: 99%

“…Such a SRK equation has been preferably used − because of its high predictive and descriptive ability of the gas–liquid equilibrium behavior in the FTS. Karimi et al showed a comparison between the results obtained by the SRK state equation, the PR equation as well as its modified versions, and Henry’s empirical equation for the determination of phase equilibrium in the process FTS, where it is strongly shown that the modified SRK equation agrees with the experimental data collected from the literature. Other methods employed including the modified PR equation show high deviations.…”

Section: Development Of a Generalized Reactor Modelmentioning

confidence: 99%

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Modeling of Catalytic Fixed-Bed Reactors for Fuels Production by Fischer–Tropsch Synthesis

2017

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A comprehensive review of the various studies reported in the literature to date on the mathematical modeling of fixed-bed reactors for the production of fuels by the Fischer–Tropsch synthesis (FTS) was carried out. It is quite clear that most of the proposed models are based on a set of assumptions that allow their wide simplification by reducing the models into forms of low complexity, due to the fact that in most cases the effects of phase equilibrium are neglected, and relatively simple Fischer–Tropsch kinetics of the power law type are used. In addition, most of the proposed modeling schemes neglect the effects of resistances to gas–liquid and liquid–solid mass transfer. On the other hand, few reports consider the energy effects under the consideration of a nonisothermal operation assuming a plug-flow behavior and a gas–liquid system. A generalized model of a fixed-bed FTS reactor is proposed which takes into account all the mass and heat transfer phenomena, as well as hydrodynamics and vapor–liquid equilibrium (VLE), based on the information given in the literature. It is evident that for fixed-bed reactors for fuel production using Fischer–Tropsch technology, there is little experimental information for validation and a need to explore different types of reactor models, such as reactor models under a trickle-flow regime considering the effects of phase distribution and dispersion under transient-state conditions.

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“…In the general description of the VLE in the FTS system, cubic equations of state (EOS) were mainly used where some authors opted for Peng-Robinson (PR) [13][14][15][16][17] and others for Soave-Redlich-Kwong (SRK) EOS [18][19][20][21][22][23]. Additionally, modifications of the two EOSs by using molecular weight of a component, instead of its acentric factor have been proposed, with modified SRK EOS showing better results compared to others, as shown in the study of Karimi et al [22].…”

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confidence: 99%

Comparison of Cubic-Plus-Association and Soave-Redlich-Kwong equations of state for prediction of vapor-liquid equilibrium of Fischer-Tropsch reaction mixture

Zivanic¹,

Stamenić²,

Todić

et al. 2019

CI&CEQ

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A Study on Vapour-Liquid Equilibria in Fischer-Tropsch Synthesis

Cited by 10 publications

References 19 publications

Performance Characteristics of Eggshell Co/SiO₂ Fischer–Tropsch Catalysts: A Modeling Study

Performance Characteristics of Eggshell Co/SiO₂ Fischer–Tropsch Catalysts: A Modeling Study

Modeling of Catalytic Fixed-Bed Reactors for Fuels Production by Fischer–Tropsch Synthesis

Comparison of Cubic-Plus-Association and Soave-Redlich-Kwong equations of state for prediction of vapor-liquid equilibrium of Fischer-Tropsch reaction mixture

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A Study on Vapour-Liquid Equilibria in Fischer-Tropsch Synthesis

Cited by 10 publications

References 19 publications

Performance Characteristics of Eggshell Co/SiO2 Fischer–Tropsch Catalysts: A Modeling Study

Performance Characteristics of Eggshell Co/SiO2 Fischer–Tropsch Catalysts: A Modeling Study

Modeling of Catalytic Fixed-Bed Reactors for Fuels Production by Fischer–Tropsch Synthesis

Comparison of Cubic-Plus-Association and Soave-Redlich-Kwong equations of state for prediction of vapor-liquid equilibrium of Fischer-Tropsch reaction mixture

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Performance Characteristics of Eggshell Co/SiO₂ Fischer–Tropsch Catalysts: A Modeling Study

Performance Characteristics of Eggshell Co/SiO₂ Fischer–Tropsch Catalysts: A Modeling Study