Study on a membrane reactor equipped with the one-end-closed silica membrane for hydrogen iodide decomposition

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

Recently, the inorganic membranes have been undergoing quick development and innovation, and becoming an attractive field of membrane separation technology including membrane reactors. The catalytic decomposition of hydrogen iodide (HI) has long been a candidate reaction for the application of membrane reactors. The decomposition of HI is an endothermic reaction and equilibrium conversions even high temperatures are low. The use of membrane reactors based on silica membranes provides the opportunity of increasing the HI-conversion. Design of the membrane reactor modules previously developed for HI decomposition tests was based on the membrane tube fixed to gas lines at each end of the membrane tube. This design was a suitable for short-size module but not viable in terms of long-size fabrication and the practical applications. In this work, a membrane reactor equipped with one-end-closed silica membrane was designed and a potential of the membrane reactor to HI decomposition was explored. The closed-one-ended silica membrane were prepared by a counter diffusion chemical vapor deposition method for the first time. Permeation performance of the one-end-closed silica membrane was investigated. On the basis of HI decomposition tests, the membrane reactor equipped with the one-end-closed silica membrane demonstrated to show a successful equilibrium shift in the production of hydrogen.