Enhancement of hydrogenation of CO2 to hydrocarbons via In-Situ water removal.

Hydrogenation of CO 2 to hydrocarbons in fixed-bed and annular reactors (AR) can be limited via problems associated with high water production as the main by-product. Selective in-situ water removal using a hydrophilic membrane can be a promising solution for enhancing reactor performance. To this aim, a one-dimensional heterogeneous model comprising mass and heat transfers in the shell and tube of a membrane reactor (MR) is proposed. Firstly, the performance of different rector configurations exhibiting similar cross sectional areas and volumes are compared. Afterwards, influential factors affecting the MR performance such as shell/tube temperature, sweep ratio (θ) and pressure ratio (φ) are investigated thoroughly. Results show that increasing initial tube/shell temperature has positive effect on total hydrocarbons yield. However, sharp and sudden temperature elevation (hot spot) due to large extent of water removal, may have detrimental effects on catalyst performance. Moreover, it is observed that increasing θ and φ alter products distribution due to the equilibrium displacement and results in the lack of H 2 for further reactions. In addition, kinetic parameters corresponding to the inhibiting effect of water are indicated to have significant roles in hydrocarbons distribution. Therefore, water removal impose various changes, which cannot be considered independently in analyzing the MR performance. Image 1 • Modeling of CO 2 hydrogenation in membrane reactor is presented. • Effect of in-situ water removal on the reactor performance is analyzed. • Hydrocarbons distribution and reactor temperature are assessed in AR and MR. • Effect of sweep ratio and sweep pressure on products yield are studied. [ABSTRACT FROM AUTHOR]