Membrane evaporation of amine solution for energy saving in post-combustion carbon capture: Performance evaluation

Abstract

In this study, we propose a membrane evaporation system for energy penalty reduction in post-combustion carbon capture (PCC) and carry out membrane evaporation of amine solutions. The effects of some key factors (i.e. evaporation temperature, gas and liquid flow rates and solvent concentration) on mass and heat transfer are systematically investigated. It is found that both evaporation temperature and gas flow rates have significant influences on vapor and heat transfer, while liquid flow rates have limited effect on mass and heat transfer in membrane evaporation. The vapor and recovered heat fluxes increase exponentially with the rise in evaporation temperature, and increase linearly with the rise in gas flow rates. The increase in evaporation temperature and gas flow rates also significantly improves the evaporation efficiency and heat recovery. Mass and heat transfer rates decrease as the concentration of the solvent increases because of the reduced vapor pressure of the liquid at higher concentration. It is estimated that the recovered heat flux can be up to 32MJm−2h−1 and heat recovery can be over 40% when the gas/liquid flow rate ratio is 150. Therefore, the proposed membrane evaporation system has great potential to save considerable energy in large-scale PCC pilot plant operation.