Fischer—Tropsch synthesis diffusivity effects

Taking these effects into account, internal pore diffusion was modeled on the basis of a wax-filled cylindrical single catalyst pore by using experimental data. The modeling was accomplished by a three-dimensional finite element method as well as by a respective differential-algebraic system. Since the Fischer-Tropsch synthesis is a rather complex reaction, an evaluation of pore diffusion limitations... 

Mass transfer effects are very important for the selectivity in the Fischer-Tropsch synthesis. Even though the reactants are in the gas phase, the catalyst pores will be filled with liquid products. Diffusion in the liquid phase is about 3 orders of magnitude slower than in the gas phase and even slow reactions may become diffusion limited. Diffusion limitations may occur through limitation on the arrival of CO to the active points or through the limited removal of reactive products.8,9... 

Figure 6.11.7 Influence of temperature and particle size on the effectiveness factor with regard to pore diffusion of Fischer-Tropsch synthesis [according to Eqs. (6.11.20)-(6.11.28)] (jess and Kern, 2009).

K Yokota, K Fujimoto. Supercritical-phase Fischer-Tropsch synthesis reaction. 2. The effective diffusion of reactant and products in the supercritical-phase reaction. Ind Eng Chem Res 30 95-100, 1991. 

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