新規CO₂分離膜の創製と実用化への導入

抄録

Membrane technology is regarded as a promising means to reduce the cost of carbon dioxide capture and storage (CCS) for global warming problem. In this paper, three types of CO₂ selective membranes were investigated for separation of CO₂/N₂ in order to remove CO₂ from the flue gas: poly(ethylene glycol) based membranes, Cs–incorporated carbon membranes and dendrimer composite membranes. In development of poly(ethylene glycol) based membranes, crosslinked poly(ethylene glycol) diacrylate membranes were prepared using water as the solvent and UV polymerization. Swelling behavior and separation performance were affected by preparation conditions, especially water concentration in polymerization mixture. In development of Cs–incorporated carbon membranes, the original carbon membrane without Cs had a lower CO₂ permeance and CO₂/N₂ separation factor under humid conditions than it did under dry conditions. On the other hand, Cs-incorporated carbon membranes had a higher CO₂ permeance and separation factor under humid conditions. It was suggested that the change in pore size distribution and the pore surface properties played an important role in improving CO₂ separation performance under humid conditions. In development of dendrimer composite membranes, a commercial-sized module of PAMAM dendrimer composite membrane, with length 1,100 mm, diameter 35 mm, and membrane area 0.4 m², was developed using the insitu modification (IM) method. Also, a long–term stability test (a separation experiment continuously running for 1,000 h) was conducted using an 800 mm module and real exhaust gas at a steel manufacturing plant. It was demonstrated the membrane module was stable for at least 1,000 h of exposure to real exhaust gas.