Enhancement of methanol, DME and hydrogen production via employing hydrogen permselective membranes in a novel integrated thermally double-coupled two-membrane reactor

• Two Pd/Ag membranes are used for improving the efficiency of hydrogen production.
• A steady state heterogeneous catalytic reaction model is applied to analyze.
• Methanol production increases 3.39% compared with conventional methanol reactor.
• DME production increases 17.34% in thermally double-coupled two-membrane reactor.
• Hydrogen production increases 13.28% in thermally double-coupled two-membrane reactor.

In this paper, a thermally double-coupled two-membrane reactor for simultaneous production of methanol, hydrogen and dimethylether (DME) by employing Pd/Ag membranes in co-current mode has been investigated. In this novel multi-tubular reactor configuration, cyclohexane dehydrogenation as an endothermic reaction has coupled with two exothermic reactions of methanol production and direct DME synthesis from syngas. Two Pd/Ag membranes are used for improving the efficiency of hydrogen production and other products in exothermic sides by separation of hydrogen from unconverted outputs of exothermic sides that are recycled to the reactor. A steady state heterogeneous catalytic reaction model is applied to analyze the performance of thermally double-coupled two-membrane reactor and comparison of the result with corresponding predictions for a conventional methanol reactor, thermally coupled reactor (coupling of methanol synthesis with cyclohexane dehydrogenation only) and thermally double coupled reactor.Modeling results show that by employing this novel configuration, methanol yield reaches to 0.4017 in comparison with 0.3885, 0.3735 and 0.362 for conventional methanol reactor, thermally double coupled reactor and thermally coupled reactor respectively.Also methanol production increases 3.39%, 7.03% and 10.94% compared with conventional methanol reactor, thermally double coupled reactor and thermally coupled reactor respectively. Simulation results illustrate that by using Pd/Ag membranes, DME production raises from 277.24 kmol h−1 in thermally double coupled reactor to 325.3 kmol h−1 in thermally double-coupled two-membrane reactor. Additionally, hydrogen production in endothermic side of thermally double coupled reactor is enhanced from 1076 to 1219 kmol h−1 in thermally double-coupled two-membrane reactor.