抄録
The feasibility of the Bunsen reaction using an ionic liquid (IL) containing iodide ions as the solvent was experimentally examined to improve the thermal efficiency of a thermochemical water-splitting iodine-sulfur (IS) process for hydrogen production using a high-temperature gas-cooled reactor (HTGR) by increasing the hydrogen iodide (HI) concentration in the Bunsen reaction. The solubility of the reactants of the Bunsen reaction, iodine (I2) and sulfur dioxide (SO2), in the IL was measured to confirm the feasibility of the reaction. 1-Butyl-3-methylimidazolium iodide ([bimi][I]) showed an I2 solubility of 4.78 mol/mol at room temperature, which was 2.47 times higher than that in hydriodic acid. [bimi][I] also showed a high SO2 solubility of 3.42 mol/mol, which was 125 times higher than that in water. The feasibility of the Bunsen reaction using the IL was confirmed in terms of the increases in I2 and SO2 concentrations in the Bunsen reaction. The HI concentration in the hydriodic acid in the Bunsen reaction using [bimi][I] was preliminary examined at room temperature, ambient pressure, and reactant composition of IL:I2:SO2:H2O=0.25-0.5:0.51-2.1:1.0:1.0 (molar ratio). The maximum HI concentration was 24.5 mol% (=69.8 wt%), which was higher than that obtained by the conventional Bunsen reaction.
