(692c) Multistability in Membrane Reformers Due to Permeance Inhibition By Competitive Adsorption of CO

Membrane steam refomers are interesting devices for the decentralized production of hydrogen as they allow the integrated production and separation of hydrogen as well as the possibility of lowering the operating temperature compared to conventional reforming processes. It has been previously shown that the performance of these devices may suffer from permeance inhibition of the hydrogen-selective membrane by the competitive adsorption of CO, one of the reaction of the products. Here, we show that that such inhibition may also lead to steady-state multiplicity. This has been attributed to the fact that, in the presence of inhibition, the mechanism limiting the performance of the reactor may shift from chemical reactions to hydrogen permeation, depending on the initial gas composition. The region of multistability depends, among other factors, on the feed composition. More specifically, it has been shown that the presence of multistability is more pronounced when feeding biogas than it is when feeding methane to the system. The findings of this work provide valuable information regarding (i) the startup procedure of the reactor that favors operating in regions of enhanced reactor peformance, (ii) procedures for carrying out a diagnosis of membrane permeance inhibition by competitive adsorption that do not require the interruption of reactor operation, and (iii) guidelines for the choice of the most appropriate membrane depending on the selected operating conditions.