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

BACKGROUND The 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 CO 2 capture. RESULTS Hybrid solutions composed of Monoethanolamine (MEA), a physical solvent, and H 2 O 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% H 2 O achieved higher rich loading, strong cyclic CO 2 capacity and the highest desorption rate over a wide range of CO 2 loadings. Also, the mass transfer performance of CO 2 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 CO 2 loading, inert gas flow rate and CO 2 partial pressure on the mass transfer performance were evaluated in terms of volumetric overall mass transfer coefficient ( K G a v ). Furthermore, a correlation was developed for CO 2 absorption into MEA/Sulfolane solution in a random packing column using semi-empirical models as functions. CONCLUSION Unlike 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 CO 2 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