WGS-mixture Separation and WGS Reaction Test in a Benchscale Multi-tubular Membrane Reactor

摘要

For pre-combustion CO_2 capture in the natural gas combined-cycle power plant, Pd membrane 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% CO_2, 15.4% H2O, 1.2% CH_4 and 60.1% H_2, representing the (623 K equilibrium shifted) reformate gas from an oxygen-fed autothermal reformer followed by a shift-reactor, under practical working conditions: T = 673 K, p_(feed) = 20-35 bar(a), p_(perm) = 15 bar(a). In the separation test, the inhibition effect o f this WGS-mi xture resulted in an overall hydrogen permeation drop of approx. 20% compared to H_2/N_2 mixtures with the same H_2 concentration, which enhanced with increasing feed pressure. In the WGS reaction test, the maximum CO conversion and H_2 recovery were both achieved as 92% at a feed/permeate pressure of 35/15 bar(a), which is favourable for CO_2 capture.