Development of a hydrogen permselective membrane reactor using a silica membrane for the IS process

The IS (Iodine-Sulfur) process is one of the thermochemical water splitting methods using iodine and sulfur as recycling agents. HI decomposition procedure to obtain hydrogen is one of the key operations in the process, because equilibrium conversion of HI is low (22% at 723 K). A silica membrane prepared by chemical vapor deposition was applied to the decomposition reaction of HI vapor for improvement of one pass conversion of HI. Hydrogen was successfully removed from the decomposition reactor between 723 K and 873 K. HI one-pass conversion was 76.4% at 873 K by removing hydrogen from the system by using the silica membrane. Total thermal efficiency can be improved by 1% for this HI conversion by calculating heat/mass balance of the process. This system was confirmed as permeation limitation reactor by the simple two-dimensional simulation. (author)