CO2 capture using EGHE-based water-lean solvents with novel water balance design

Maintaining water balance in water-lean solvents is drawing special attention as it may affect the capture performance and process stability. In this study, novel water-lean solvents containing ethylene glycol monohexyl ether (EGHE) and secondary alkanolamines was proposed for energy-saving postcombustion CO 2 capture. Excess water from wet flue gas can be discharged from the desorber overhead condensate which can produce a spontaneous phase-separation feature. Less than 0.8 mass% EGHE was observed in the water-rich phase of the biphasic condensate. Effect of water content in these absorbents on CO 2 capture performance was discussed. Most notably, regeneration energy consumption increased significantly as increasing water content in the absorbent. The proposed water-lean absorbents with 10 % H 2 O can reduce the regeneration heat duty by about 40% in comparison with aqueous MEA, indicating that the novel water balance design can make it competitive in a practical sense.