WGS-mixture separation and WGS reaction test in a bench-scale multi-tubular membrane reactor

For pre-combustion CO2 capture in the natural gas combined-cycle power plant, Pd me mbrane reactors are a promising option. A bench-scale multi-tube membrane reactor has been built in ECN and successfully demonstrated the operation for WGS- mixture separation and WGS reaction test with 3 Pd membranes of approx. 5.6 μm thick and 44 cm long in parallel configuration. Both tests were investigated with the following mixture: 4.0% CO, 19.2% CO2, 15.4% H2O, 1.2% CH4 and 60.1% H2 representing the (623 K equilibrium shifted) reformate gas from an oxygen-fed autothermal reformer followed by a shift-reactor, under practical working conditions: , , . In the separation test, the inhibition effect o f this WGS-mixture resulted in an overall hydrogen permeation drop of approx. 20% compared to H2/N2 mixtures with the same H2 concentration, which enhanced with increasing feed pressure. In the WGS reaction test, the maximum CO conversion and H2 recovery were both achieved as 92% at a feed/permeate pressure of 35/15 bar(a), which is favourable for CO2 capture.