Modeling and analysis of ceramic-carbonate dual-phase membrane reactor for carbon dioxide reforming with methane

A new high temperature tube shell membrane reactor (MR) design for separation and utilization of CO(2) from the flue gas and for simultaneous production of syngas through carbon dioxide reforming of methane (CRM) is reported. The MR is based on a dual-phase CO(2) permeation membrane consisting of mixed-conducting oxide and molten carbonate phases. High temperature CO(2)-containing flue gas and CH(4) are respectively fed into the shell and tube sides of the reactor packed with a reforming catalyst. Under performance conditions, CO(2) permeates selectively through the membrane from the shell side to the tube side and reacts with CH(4) to produce syngas. Additionally, the heat from the flue gas can transfer directly through the membrane to provide energy for the endothermic CRM reaction. An isothermal steady-state model was developed to simulate and analyze CRM in the MR in this work. The effect of the design and operational parameters, such as inlet CH(4) flow rate, shell side CO(2) partial pressure and the flue gas composition, i.e., containing O(2) or not, as well as the membrane thickness on the reactor performance with respect to the CH(4) conversion and the CO(2) permeation flux were investigated and discussed. The results show that the MR has a high efficiency in separating and utilizing CO(2) from the flue gas. For a CH(4) space velocity of 3265.31 h(-1), with a membrane thickness of 0.075 mm and the shell side CO(2) partial pressure of 1 atm, a CH(4) conversion of 48.06% and an average CO(2) permeation flux of 1.52 mL(STP) cm(-2) min(-1) through the membrane tube at 800 degrees C are obtained. Further improvement of the MR performance can be achieved by involving O(2) in the permeation process. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.