A standard function to evaluate optimal absorption and desorption temperature of SO2 absorbent: Taking amine alkyl organosilicon as example

Abstract

A low viscous and high thermal stable dibutyl-(1,1-dimethyl-3,3,3-triphenyl-disiloxanylmethyl)-amine (DDTDA) was synthesized by two steps reaction. Its reaction enthalpy and entropy change with SO2 were found to be −85.39 kJ/mol and −244 J mol−1 K−1, whose absolute value are much higher than those of ionic liquids (ILs) and deep eutectic solvents (DESs). An objective function was proposed to balance reversible capacity and regeneration sensible heat consumption per unit absorption capacity. Based on it, the optimal absorption and desorption temperature of DDTDA were calculated and the temperature difference was found to be much lower than those of ILs and DESs, which implied its regeneration sensible heat is the lowest. According to the function, the traditional method to evaluate two absorbents by simply comparing their capacities at a certain temperature is unscientific. Different absorbents have different optimal absorption and desorption temperature range.