CO2 Capture and H2 Recovery Using a Hollow Fiber Membrane Contactor

Abstract

In this study, hydrogen was recovered and purified by using a membrane contactor unit from CO2-rich gas without the use of any basic chemicals such as amines. The membrane operational parameters were adjusted to achieve high CO2 removal and H2 recovery. The effects of gas flow rate, pressure, gas composition (CO2/H2 ratio), pressure difference between liquid and gas, and gas/liquid ratio on CO2 removal and H2 recovery were investigated. Depending on the gas flow rate, the contact time between gas and liquid could be controlled, changing the absorption amounts of CO2 and H2. Regarding gas composition, an increase in the CO2/H2 ratio from 0.25 to 1 boosted H2 recovery. Furthermore, increasing the CO2/H2 ratio above 1 (from 1 to 3) generally reduced H2 recovery from 98.7% to 83%. Additionally, supplementation with the optimal amount of additive enhanced CO2 removal and H2 recovery. Thus, using a membrane contactor system results in high CO2 removal (82.7–93.5%) and H2 recovery (91.5–98.7%). Moreover, H2 production and separation can be performed in one system, implying that CO2 removal can be performed more efficiently by the membrane contactor. This study offers a new and promising route for producing high-purity H2 while removing CO2.