Optimal activated carbon for separation of CO2 from (H2 + CO2) gas mixture

Abstract Seven types of activated carbon were used to investigate the effect of their structure on separation of CO2 from (H2 + CO2) gas mixture by the adsorption method at ambient temperature and higher pressures. The results showed that the limiting factors for separation of CO2 from 53.6 mol% H2 + 46.4 mol% CO2 mixture and from 85.1 mol% H2 + 14.9 mol% CO2 mixture were different at 20 °C and about 2 MPa. The best separation result could be achieved when the pore diameter of the activated carbon ranged from 0.77 to 1.20 nm, and the median particle size was about 2.07 µm for 53.6 mol% H2 + 46.4 mol% CO2 mixture and 1.41 µm for 85.1 mol% H2 + 14.9 mol% CO2 mixture. The effect of specific area and pore diameter of activated carbon on separation CO2 from 53.6 mol% H2 + 46.4 mol% CO2 mixture was more significant than that from 85.1 mol% H2 + 14.9 mol% CO2 mixture. CO2 in the gas phase can be decreased from 46.4 mol% to 2.3 mol%–4.3 mol% with a two-stage separation process