Challenge for adapting a hydrogen permselective membrane reactor to improve thermochemical IS process

Myagmarjav, O.  ; 田中 伸幸 ; 野村 幹弘*; 久保 真治  

Myagmarjav, O.; Tanaka, Nobuyuki; Nomura, Mikihiro*; Kubo, Shinji

In this study, we propose an iodine-sulfur cycle, a promising thermochemical water splitting process for CO-free hydrogen production, with the aim of contributing low-carbon society. One important task is to improve efficiency of the iodine-sulfur process due to poor equilibrium of hydrogen iodide (HI) decomposition. Efficient separation of hydrogen using a membrane reactor is an effective method of improving the conversion of the HI decomposition. When hydrogen is removed selectively from reaction field with the use of membrane, chemical equilibrium of the reactions is shifted toward product side according to Le Chateliers principle, resulting in increased the conversion of the HI decomposition. We developed membrane reactor assembled with 95 mm long silica membrane in the HI decomposition. It was found that the conversion can be improved twice (50%) or greater than equilibrium conversion (20%) at 400C. Elemental technologies of the membrane reactors were demonstrated for the HI decomposition. The thermochemical iodine-sulfur process is expected to be part of future key technologies in coming low-carbon society by producing efficiently CO-free hydrogen in large-scale.