Development of ceramic membranes for large-scale hydrogen production via thermochemical iodine-sulfur process

Myagmarjav, O.  ; 田中 伸幸 ; 野口 弘喜  ; 久保 真治  ; 野村 幹弘*; 竹上 弘彰 

Myagmarjav, O.; Tanaka, Nobuyuki; Noguchi, Hiroki; Kubo, Shinji; Nomura, Mikihiro*; Takegami, Hiroaki

Hydrogen is attracting global attention as an energy carrier for future energy delivery systems because of its lack of carbon dioxide emission. To realize a hydrogen energy society, it is necessary to develop effective and safe hydrogen-production methods. The thermochemical iodine-sulfur process is one of the promising methods for massive hydrogen production without carbon dioxide emissions. Separation of hydrogen from gaseous mixture of hydrogen iodide and iodine is one of the technical issues in the development of this process. Silica is the most developed of the porous ceramics and is one of the most promising materials for hydrogen-separation membranes. In the present work, a high performance silica membrane was developed for application in membrane reactors that produce hydrogen by hydrogen iodide decomposition. These silica membranes were prepared with a three-layer structure comprising an porous alumina support layer, an intermediate silica layer fabricated using a sol-gel, and a top silica layer fabricated by counter-diffusion chemical vapor deposition. Scaling up of this type of silica membrane is attempted for the first time in order to produce hydrogen at a large-scale. The resulting membranes exhibit good surface uniformity with length and have no defects, especially existence of pinholes. Thus, these silica membranes appear to be suitable for membrane reactor applications to produce hydrogen in on a large-scale.