Use Of Ionic Liquids As Absorbents To Separate So_2 In So_2/o_2 In Thermochemical Processes To Produce Hydrogen

摘要

In the thermochemical cycles such as the SI (sulfur-iodine) cycle, the Westinghouse process, and Ispra Mark 13 process, SO_2 needs to be separated and purified to enhance system efficiency. As novel absorbents with non-volatility, thermal stability and high SO_2 absorption capability, the characteristics of ionic liquids (ILs) as SO_2 absorbents were investigated to separate SO_2 in SO_2/O_2 gaseous mixtures from the sulfuric acid decomposer. SO_2 absorption and desorption experiments showed that SO_2 solubility and absorption rate in ILs were influenced mainly by anions of ILs. [BMIm][Cl] and [BMIm][OAc] (1.40-1.69 SO_2 gmol/ILs gmol) showed the highest SO_2 solubility among the tested ILs at 50 ℃ and 0.67 atm P_(SO_2). Interestingly, [BMIm][0Ac] showed irreversibility in the cycle of absorption and desorption. [BMIm][MeSO_4] showed moderate SO_2 solubility and good reversible cycles of absorption and desorption. The dependency of temperature and pressure on SO_2 solubility of [BMIm][MeSO_4] was scrutinized.