A novel axial-flow spherical packed-bed membrane reactor for dimethyl ether synthesis: Simulation and optimization

In order to improve the performance of conventional tubular reactors, the concept of spherical membrane reactors has been proposed as an alternative to eliminate the problem of pressure drop and to increase the production rate. Regarding this, a novel axial-flow spherical packed-bed membrane reactor (AF-SPMR) has been developed for dehydration of methanol. This configuration consists of two concentric spheres in which dimethyl ether (DME) synthesis occurs in the inner sphere coated by a water perm-selective membrane. The operating conditions as well as length per radius for the AF-SPMR were optimized using differential evolution (DE) method to maximize the mole fraction of DME in the outlet point of the reactor. A comparison was made between the optimized AF-SPMR (OAF-SPMR), AF-SPMR, axial-flow spherical packed-bed reactor (AF-SPR) and the conventional reactor (CR). The optimization results indicate the superiority of OAF-SPMR to all previous configurations due to achieving 13.5% increase in the mole fraction of DME. In addition to much lower pressure drop in AF-SPR (nearly 98% reduction); considerably higher production of DME in AF-SPMR represents the main advantages of this configuration in comparison with CR.