Development of pilot WGS/multi-layer membrane for CO2 capture

For pre-combustion CO2 capture processes, a 1 Nm3/h water gas shift (WGS)/multi-layer membrane system has been developed. Simulated syngas (H2: 25–35, CO: 60–65, CO2: 5–15 vol.%) was used in these experiments. The 1 Nm3/h WGS/multi-layer membrane system consisted of mass flow controllers, water gas shift reactors, gas/steam separators, five layer Pd–Cu membrane module, back pressure regulator, gas chromatograph (GC) analyzers and nondispersive infrared (ND-IR) gas analyzers. The operation conditions of WGS/multi-layer membrane system were 200–400 °C, 10–20 bar and steam/carbon ratios in WGS were between 2.0 and 5.0. In the experiments of WGS/multi-layer membrane system, the average gas concentration before membrane module was H2: 57–58, CO2: 42–43, CO: 0.2–0.3 vol.%. The CO2 concentration of retentate flow reached up to 80 vol.% and the H2 concentration of permeate flow was over 99 vol.%.

• A pilot scale water gas shift with multi-layer Pd–Cu membrane module has been developed.
• The pressure of the hybrid system enhances hydrogen permeation and results in concentrating CO2 in retentate flow.
• The CO2 concentration of retentate flow reached over 80 vol.% from 5 vol.% of original syngas.
• We conclude the WGS/membrane hybrid system is a promising way to achieve 90 vol.% of CO2 in IGCC plants.