Fischer-Tropsch Wax Synthesis in Supercritical Phase Process: Addition Effect of 1-Tetradecene.

Abstract

Fischer-Tropsch synthesis over Co/SiO2 catalysts coupled with a small amount of 1-tetradecene has been carried out in the presence of supercritical fluid(SCF). It was found that SCF could extract the products from the catalyst bed efficiently, and consequently, the mass transfer for both reactant gas and products were enhanced, that allowed increased CO conversion and hydrocarbon yields possible. The addition of 1-tetradecene to the reaction system increased the formation rate of hydrocarbons larger than C14 significantly, but decreased the yields of C1-C13 hydrocarbons, which made the carbon number distribution of products flatter than in the case without olefin addition. Moreover, wax composition analysis also showed that the average molecular weight, and the degree of saturation of wax increased, while the content of oxygenates decreased by addition of 1-tetradecene. Effects of catalyst pore size, H2/CO ratio of syngas, and concentration of 1-tetradecene cofeeding were also investigated.