CO_2 CAPTURE AND ENRICHMENT BY NOVEL HOLLOW FIBER FACILITATED TRANSPORT MEMBRANE MODULE WITH LOW ENERGY CONSUMPTION

摘要

A novel facilitated transport membrane module for gas separation is proposed in which a carrier solution is forced to permeate the membrane. Both a feed gas and a carrier solution are supplied to the feed side (high pressure side) of the capillary ultrafiltration membrane module and flow upward. Most of the carrier solution which contains dissolved CO_2 permeates the membrane to the permeate side (low-pressure side), where the solution liberates CO_2 to become a lean solution, and the lean solution is returned to the lumen of the capillary module by a pump. In this study, we performed experiments at several operational conditions by using diethanolamine (DEA) and 2,3-diaminopropionic acid (DAPA) as carriers. The feed side pressure was about 1 atm and the permeate side pressure was about 0.05 atm. CO_2 in the feed gas was successfully enriched to 97.1-99.9% by one-stage separation. When the CO_2 mole fraction in the feed was 0.05, the CO_2 permeance and the CO_2/N_2 selectivity were 8.9-9.4 x 10~(-4) mol m~(-2) s~(-1) kPa~(-1) and 1020-2320, respectively, and the CO_2 recovery was 72-76 %. The energy required for CO_2 capture, enrichment and liquefaction was about 0.27kWh kgCO_2~(-1), which is much lower than those by using polymeric membranes, conventional gas absorption processes consisting of absorption and stripping column. The proposed process is promising for the CO_2 recovery with low energy consumption.