CO2/CH4 분리를 위한 프로필렌카보네이트/물 흡수제 특성 평가 및 막접촉기의 적용

To produce renewable biomethane from biogas, the properties of physical absorbents such as water, methanol, 1-methyl-2-pyrrolidone (NMP), poly(ethylene glycol) dimethylether (PEGDME), and propylene carbonate (PC) were studied, and PC was applied to membrane contactor systems. Among physical absorbents, PC exhibited a high contact angle of 58.3° on polypropylene surface, and a PC/water mixture (5 wt%) increased the contact angle to 90°. Furthermore, the PC/water mixture presented higher CO2 absorption capacities (0.148-0.157 mmol/g) than that of water (0.121 mmol/g), demonstrating a good property as an absorbent for membrane contactors. Actual operations in membrane contactors using the PC/water mixture resulted in CO2 removal of 98.0-97.8% with biomethane purities of 98.5-98.3%, presenting a strong potential for biogas treatment. However, the PC/water mixture yielded moderate improved in CO2 removal and methane recovery, as compared with water in the membrane contactor operation. This is originated from insufficient desorption processes to reuse absorbent and low CO2 flux of the PC/water absorbent. Thus, it is requiring optimizations