Pd-based composite membrane and its high-pressure module for pre-combustion CO2 capture

This study investigates configuration of a module for withstanding high pressure and temperature for CO2 capture from a coal gasifier. In order to increase the durability of the module at high pressure and temperature, a flange-type unit-cell module was installed in a high-pressure chamber. Hydrogen permeation and N2 leakage tests showed that H2/N2 selectivity remained at ∼4000 after ∼300 h at a pressure difference of 2000 kPa (∼20 bar) and 673 K. A CO2 capturing test was carried out at 673 K and a pressure difference of 2000 kPa with a 40% CO2 + 60% H2 feed gas mixture, which is similar to the composition in a coal gasifier after shift reaction and H2O removal. It was shown that CO2 could be enriched up to 78–95% with a hydrogen recovery ratio of 82–97% when the feed flow rate was 0.05–0.17 Nm3 h−1 with a membrane surface area of 16. 6 cm2.