Conceptual feasibility studies of a CO (X) -free hydrogen production from ammonia decomposition in a membrane reactor for PEM fuel cells

Abstract

CO (X) -free hydrogen production from ammonia decomposition in a membrane reactor (MR) for PEM fuel cells was studied using a commercial chemical process simulator, Aspen HYSYSA (R). With process simulation models validated by previously reported kinetics and experimental data, the effect of key operating parameters such as H-2 permeance, He sweep gas flow, and operating temperature was investigated to compare the performance of an MR and a conventional packed-bed reactor (PBR). Higher ammonia conversions and H-2 yields were obtained in an MR than ones in a PBR. It was also found that He sweep gas flow was favorable for X (NH3) enhancement in an MR with a critical value (5 kmol h(-1)), above which no further effect was observed. A higher H-2 permeance led to an increased H-2 yield and H-2 yield enhancement in an MR with the reverse effect of operating temperature on the enhancement. In addition, lower operating temperature resulted in higher X (NH3) enhancement and H-2 yield enhancement as well as NG cost savings in a MR compared to a conventional PBR.