酸对有机胺BHEP-醚DEGBE水溶液相变吸收SO2的影响OA

In order to reduce energy consumption in SO2 capture by organic amine,a phase-change absorbent composed of BHEP[N,N′-bis(2-hydroxyethyl)piperazine]and DEGBE(diethylene glycol monobutyl ether)aqueous solution was developed.The effects of 4 types of acids,namely boric acid,sulfuric acid,phosphoric acid and citric acid on the absorption,desorption and phase change properties of BHEP were investigated.The results show that both the absorption-desorption performance and phase separation performance are significantly influenced by the type of acid and its pKa.The stronger the acidity of an acid added before absorption and the higher the concentration of acid used,the more the content of the polar amine salts formed,the greater the polarity difference between the non-polar ether DEGBE and the polar ammonium salts,the easier the phase separation.In addition,the smaller the distribution rate of DEGBE,while the larger the distribution rate of SO2,sulfuric acid,BHEP,and H2O in lower phase.Furthermore,the stronger the inhibition effect on absorption,the smaller the absorption capacity;the better the improvement effect on desorption,the higher the desorption rate and cyclic absorption capacity,and the lower the energy consumption for regeneration.Among them,the best phase separation selectivity and the higher desorption rate are achieved by the BHEP-DEGBE solution adding sulfuric acid.Thus,sulfuric acid is suitable as a desorption and phase separation promoter in aqueous mixtures of BHEP and DEGBE system.1H NMR indicates that the type and dosage of acid do not change the phase transition mechanism and the absorption mechanism of BHEP's chemical absorption of SO2.