Characterisation of the electrochemical water gas shift reactor (EWGSR) operated with hydrogen and carbon monoxide rich feed gas

Water gas shift units are used to raise the H2 yield of reforming processes by converting CO to CO2 and additional H2. Additional subsequent processes are required to separate H2 from the product gas stream to obtain pure H2. This study investigates a novel electrochemical membrane reactor, where the water gas shift reaction occurs electrochemically. The reactor is operated at 393 K and 403 K with electrical energy to enable hydrogen purification in terms of electrochemical pumping, as well as a simultaneous electrochemical CO oxidation to increase the yield of purified H2. The experimental results show the influence of several operation parameters upon its operation characteristics (e.g. cell voltage, electrochemical CO oxidation, the energy demand, etc.). The process yielded high overall exergy efficiencies of, e.g. 78.3%, whereas the anodic outlet stream contributed with 35%-units, and the purified hydrogen with 43.3%-units.

► Simultaneous H2 generation and separation from H2, CO, H2O containing feed gas. ► Electrochemical CO and H2 oxidation interplay as a function of the EWGSR voltage. ► Effluent gas H2/CO ratio adjustment according to needs of consecutive processes. ► CO oxidation current fraction as a function of operation conditions. ► Experimental data based process efficiency evaluation through exergy analysis.