$SO_2/O_2$ Separation Process with EMIm[ $EtSO_4$ ] in SI Cycle for the Hydrogen Production by Water Splitting

ABSTRACT SO 2 has been absorbed and separated selectively by an ionic liquid from SO 2 /O 2 mixture decomposed from sulfuric acid during the thermochemical SI cycle for the water splitting. In order to design and operate high pressure SO 2 /O 2 separation system, the solubility of SO 2 in [EMIm]EtSO 4 (1-ethyl-3-methylimidazolium ethylsulfate) has been measured by Magnetic Suspension Balance at high pressure and temperature. Based on the measured solubility, a pressurized separation system was set up and operated. 194 L/h of SO 2 (SO 2 :O 2 = 0.65:1) has been separated with 99.85% of O 2 at the vent of absorption tower, which is 22.7% of the theoretically ideal capacity of the system. This discrepancy results from the reduced contact between the gaseous SO 2 and the ionic liquid. Increased SO 2 supply, scale-up of the absorption column, and a faster ionic liquid circulation speed were suggested to improve the separation capacity.KEY WORDS :SO 2 /O 2 separation(SO 2 /O 2 분리), [EMIm]EtSO