Experimental study on CO2 mass transfer performance of TETA-DEEA-TMS-H2O phase separation absorbent in hollow fiber membrane contactor
Chemical absorption methods,especially the amine method,are currently the most promising for industrialization of CO2 capture in post-combustion exhaust gases.However,traditional amine solutions[based on 30％monoethanolamine(MEA)]have high energy consumption for regeneration,and CO2 absorption in packed towers may have operational problems such as liquid flooding,foaming,and entrainment.The amine-based phase separation CO2 absorbent is expected to significantly reduce CO2 desorption energy consumption,because only the CO2-rich phase solution needs to be sent for desorption.In this paper,the CO2 absorption mass transfer was enhanced by a highly efficient amine-based phase separation absorbent coupled with a hollow fiber membrane contactor.Firstly,the comprehensive CO2 absorption-desorption performance and phase-separation characteristics of several absorbents were investigated by using CO2 absorption-desorption device.The experimental results showed that triethylenetetramine(TETA)-diethylaminoethanol(DEEA)-cyclobutanesulfone(TMS)-water had better phase-separation and CO2 capture performance.Then,the effects of CO2 loading,TETA concentration,liquid phase temperature,liquid flow rate,inlet gas velocity,and CO2 partial pressure on the CO2 absorption flux of TETA-DEEA-TMS-H2O phase separation absorbent were investigated in a hollow fiber membrane contactor.The results showed that the CO2 absorption flux decreased with the increase of the CO2 loading and increases with the increase of the liquid phase temperature,liquid flow rate,inlet gas velocity,and CO2 partial pressure.At the same time,the CO2 absorption flux tended to increase and then decrease with increase of the TETA concentration due to phase separation.The CO2 removal rate had a negative correlation with the inlet gas velocity and CO2 partial pressure.Finally,a more accurate prediction model of the gas-phase total mass transfer coefficient KG was established with an absolute average deviation of 11.94％.
CO2 capturemembrane contactorsphase separation absorbentabsorption and desorptionmass transfer
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