Membrane Evaporation for Energy Saving in CO2 Chemical Absorption Process Using a Polybenzimidazole Film: Mass and Heat Transfer

Abstract

Intensive energy consumption remains a major challenge for the commercial application of CO2 chemical absorption. In this study, a membrane evaporation system based on PBI film was proposed for recovering latent heat from the hot lean CO2 solution in order to reduce the energy penalty during CO2 capture process. The effects of key operational parameters (i.e., evaporation temperature, sweeping gas flow rate, and liquid flow rate) were systematically investigated. It was found that both vapor flux and recovered heat flux had exponential increases when the evaporation temperature increased. Sweeping gas flow rate and liquid flow rate had limited effects on both mass and heat transfer in the membrane evaporation process. The PBI film showed good stability during a 14 days’ duration experiment. Reducing the membrane thickness can significantly improve the membrane evaporation performance. From the viewpoint of energy evaluation, when the evaporation mass reached 10 g/kg solution, the regeneration energy consu...