Controlling CO2 emissions from low-concentration sources like coal-fired power plants and steel mills is crucial for achieving"carbon neutrality".Amine-based CO2 capture technology is a lead-ing contender for industrial application.This study aims to overcome limitations in energy consumption associated with amine-based processes by developing an efficient phase-separating CO2 absorbent.The structural effects of primary and secondary amines on the phase separation characteristics of amine-n-butanol-water absorbents after CO2 absorption were investigated.The role of tertiary amines in the ab-sorption-desorption and phase separation performance of 3AP-NBA-H2O was also studied.Experimen-tal results showed that the 3-aminopropanol(3AP)-n-butanol(NBA)-water absorbent had certain advantages in terms of rich CO2 phase viscosity,amine distribution,volume,and phase transition criti-cal point,indicating good phase separation characteristics.The addition of tertiary amines significantly reduced the viscosity of the rich CO2 phase while increasing the CO2 cycling capacity and desorption rate per unit volume of the solution.The novel 20％3AP-10％N,N-dimethylethanolamine(DMEA)-40％NBA-30％H2O phase-separating absorbent had a rich phase volume of 61.2％and a viscosity of only 6.73 mPa·s.The proportion of amine in the rich phase was 91.2％,with desorption rate and CO2 cycling capacity reaching 72.00％and 1.42 mol·L-1,respectively.Compared to the absorbent with 30％3AP-40％NBA-30％H2O,the desorption rate and CO2 cycling capacity were improved by 88.6％and 86.8％,respectively,while showing an improvement of 46.8％and 13.6％compared to a 30％mo-noethanolamine(MEA)solution.
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