Fast screening of amine/physical solvent systems and mass transfer studies on efficient aqueous hybrid MEA/Sulfolane solution for postcombustion CO2 capture

Abstract

AbstractBACKGROUNDThe addition of a physical solvent to a traditional chemical absorbent has been shown to improve the absorption and desorption performance of the absorbent system. This type of novel absorbent system combining a single physical solvent with an amine solvent is a promising development in the industrial application of CO2 capture.RESULTSHybrid solutions composed of Monoethanolamine (MEA), a physical solvent, and H2O were comprehensively investigated using the rapid solvent screening apparatus and a VLE apparatus. The results show that 30 wt% MEA with 20 wt% Sulfolane and 50 wt% H2O achieved higher rich loading, strong cyclic CO2 capacity and the highest desorption rate over a wide range of CO2 loadings. Also, the mass transfer performance of CO2 absorption into the 30 wt% MEA and 20 wt% Sulfolane solution was investigated in a lab‐scale random packing column. The effects of liquid flow rate, liquid feed temperature, lean CO2 loading, inert gas flow rate and CO2 partial pressure on the mass transfer performance were evaluated in terms of volumetric overall mass transfer coefficient (KGav). Furthermore, a correlation was developed for CO2 absorption into MEA/Sulfolane solution in a random packing column using semi‐empirical models as functions.CONCLUSIONUnlike for amine solution alone, inert gas flow rate is an indispensable operating parameter in the MEA/Sulfolane system. A mass transfer correlation model was established and holds significance in studying the kinetics of CO2 absorption by a mixture of physical and chemical solvents and for the optimal design of Dixon‐ring random packing columns. © 2019 Society of Chemical Industry