Process Intensification by Membrane Reactors: High-Temperature Water Gas Shift Reaction as Single Stage for Syngas Upgrading

Pd-based membrane reactors (MRs) selectively removing hydrogen shift the equilibrium conversion of this new reactor type to values higher than those imposed by thermodynamics to traditional reactors. Thus, the equilibrium conversion of CO is significantly increased and can be very strongly depending on the hydrogen extracted also at a higher temperature. This property of the MRs offers important benefits also in terms of process intensification. In the typical high-temperature range for this reaction, i.e., 300-450°C, the performance of an MR turned out to be so effective that the two reactors of a traditional process can be replaced by one MR of lower volume, too. The conversion of the MR is higher than the one of the whole traditional process which includes a heat exchanger in addition to two reactors. Consequently, less and smaller unit operations are required when an MR operates the water gas shift reaction pursuing the process intensification philosophy.