SUPERCRITICAL-PHASE FISCHER-TROPSCH SYNTHESIS REACTION .2. THE EFFECTIVE DIFFUSION OF REACTANT AND PRODUCTS IN THE SUPERCRITICAL-PHASE REACTION

A Fischer-Tropsch synthesis reaction was conducted in a supercritical fluid medium with use of a fixed bed reactor. n-Hexane was used as the supercritical fluid. The typical reaction conditions utilized were 240-degrees-C and 45 bar, which consisted of 10 bar for syn-gas and 35 bar for n-hexane. Although the rate of the reaction and the diffusion of reactants were slightly lower than those in the gas-phase reaction, the removal of reaction heat and waxy products from the catalyst surface was much more effective than in the gas-phase reaction. The olefin content in the hydrocarbon product was much higher in the supercritical-phase reaction than in the liquid-phase reaction or in the gas-phase reaction. It was attributed to the short residence time of the product in the catalyst bed for the supercritical-phase reaction, which was caused by the well-balanced desorption and diffusion of the products.