Application of pilot-scale membrane contactor hybrid system for removal of carbon dioxide from flue gas

摘要

A pilot-scale membrane contactor hybrid process was applied to recover CO_2 from the flue gas. Porous polyvinylidenefluoride (PVDF) hollow fiber module was used as membrane contactor and its performance was compared with a conventional packed column. The CO_2 from the flue gas was removed by the gas absorbers using monoethanolamine (MEA) and triethanolamine (TEA) solution as the absorbent. Then, the CO_2 was recovered from the absorbent by the thermal stripping tower with steam and the stripped absorbent was recycled. The membrane contactor increased the available gas-liquid contactor area and mass transfer coefficient, and thus the hybrid process showed a higher CO_2 removal efficiency than the conventional absorption tower. PVDF module with an asymmetric pore structure showed a stable gas-liquid interface, and the CO_2 absorption rate per unit volume of the membrane contactor was 2.7 times higher than that of the packed column. In addition, the membrane contactor hybrid process was successfully operated for 80 h maintaining a greater CO_2 removal efficiency of above 90%. The gas absorption systems were evaluated from the viewpoint of electricity.