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

Abstract

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 °C are obtained. Further improvement of the MR performance can be achieved by involving O 2 in the permeation process.