Fischer-Tropsch reaction mixture permeation through a silicalite-1 membrane reactor and its effect on the produced hydrocarbons distribution

The quantification of the permeation of the Fischer-Tropsch reaction mixture through a silicalite-1 zeolite membrane in which is integrated in to fixed bed reactor was theoretically investigated. The approach is based on the prediction of the permeation parameters by using two different mechanisms including surface diffusion and gaseous diffusion. It was found that under our investigated conditions, the total permeation could be governed by surface diffusion model since the contribution of this mechanism is dominant versus the gaseous diffusion. Noteworthy, our results show that except for the selective gas permeation of carbon dioxide, the measuring factors of different permeates were proportional to the operating pressure. Hydrocarbons with low molecular weight diffuse greater than long-chain hydrocarbons. Furthermore, the high adsorbed molecules are more likely to be affected by the high processing temperature. It can be also highlighted that the permeate amounts has no important effect on the product distribution which is characterized by the olefins to paraffins ratios. So the assumption that considers the separation of CO 2 without assuming other components permeation is well supported.