CO2 reforming of methane for H2 production in a membrane reactor as CO2 utilization: Computational fluid dynamics studies with a reactor geometry

Abstract

Computational fluid dynamics (CFD) studies have been carried out for CO2 reforming of methane in both a packed-bed reactor (PBR) and a membrane reactor (MR) with a heating tube as a heat source at the center of a reactor. The effect of a reactor geometry on the temperature and H2 and CH4 concentration profiles within a PBR and a MR have been investigated numerically by changing the distance of membranes from the center of a heating tube (Dcenter = radial distance between the center of the reactor and the center of the membrane) for a given heating tube temperature. The distances of the center of the membranes in a MR from the reactor center were 0.028 m, 0.03 m, 0.033 m, 0.035 m, 0.038 m, 0.04 m, 0.042 m, 0.044 m and 0.045 m. With the help of COMSOL Multiphysics® modeling software, it was possible to visualize temperature and concentration profiles both axially and radially. Interestingly, it was found that H2 enhancement is proportional to both Dcenter and the magnitude of the H2 flux. Further studies for the effect of a heating tube radius proposed an optimum radius for a maximum H2 yield enhancement in a MR. Consequently, it turned out that CFD studies can be used as a critical guideline for an efficient reactor design focusing on a reactor geometry in a MR for given conditions.