A convenient method for phase separation and composition determination of the Bunsen reaction products in sulfur-iodine hydrogen production process

During the integrated operation of the sulfur-iodine process, it is important to conveniently and quickly measure the composition of the Bunsen reaction products and to ascertain the location of each phase in the liquid-liquid phase separator. First, the method to determine each composition in HIx phase system which contains four components of HI, I2, H2O, and H2SO4 was newly proposed using only the data of H+ and I− contents and the density of the HIx phase. This method has the advantage to replace the complicated and time-consuming traditional titration step of I2. The calculated I2/HI molar ratios were within an error of ±5% at all temperature conditions, indicating that this method was suitable for I2 composition analysis. Meanwhile, the use of an electrical conductivity sensor was discussed as a sensing technology during the phase separation of Bunsen reaction products. The electrical conductivity was measured using different compositions of the Bunsen reaction products. The conductivity difference between H2SO4 and HIx phase solutions was approximately 478-822 mS/cm in the main compositional range of the Bunsen reaction products. Therefore, this method can replace the traditional phase separation method using a DP (differential pressure) cell.