| CO2 capture is a hot research topic today.In industry,alcohol amine solution is employed to chemically capture CO2.The energy consumption in the process of regenerating absorbent,however,is large;there is more room to improve the CO2 absorption capacity.In this thesis,a series of novel aminofunctionalized ionic liquid-amine-water phase change absorption systems were prepared,and their performances for absorbing CO2 were studied.After absorbing CO2,phase change occurs;the absorption products are rich in lower phase and only the lower phase needs to be regenerated,which reduce the regeneration energy consumption significantly.Therefore,the absorbents developed in this thesis present a good perspective in industry.(1)Three functional ionic liquids with amino groups were synthesized,i.e.,[TETA][Gly],[TETA][Lys]and[TETA][Arg],which were coupled with H2O,ethanol,PEG200,DEEA,MDEA and PMDETA to form 18 new absorption systems.Phase change appeared when[TETA][Gly]-ethanol,[TETA][Lys]ethanol,[TETA][Arg]-ethanol,[TETA][Gly]-DEEA-H2O,[TETA][Gly]PMDETA-H2O and[TETA][Lys]-PMDETA-H2O absorbed CO2,[TETA][Gly]DEEA-H2O showed the best CO2 absorption performance and was selected as the final CO2 absorbent.(2)The effects of absorbents composition,absorption temperature and regeneration temperature on CO2 absorption by[TETA][Gly]-DEEA-H2O were studied.The optimum CO2 absorption by[TETA][Gly]-DEEA-H2O(4 M,molar ratio of[TETA][Gly]to DEEA is 3:7)was observed under atmospheric pressure and 30℃,where the CO2 absorption capacity was 3.479 mol CO2/L,the volume of CO2-rich lower phase accounts for about 48%of the total absorbents,the regeneration efficiency is 98.01%at 140℃,and the CO2 absorption capacity was still above 90%after four cycles of absorption and desorption.(3)The results of 13CNMR spectrum characterization showed that CO2 was mostly absorbed by[TETA][Gly]and the product of carbamate was formed in lower phase;the minority of CO2 was also absorbed by DEEA into lower phase while most of DEEA was in the upper phase.(4)The absorption of the simulated flue gas composed of 85 v%N2 and 15 v%CO2 by[TETA][Gly]-DEEA-H2O(4 M,molar ratio of[TETA][Gly]to DEEA is 3:7)was investigated.The CO2 absorption capacity was 3.431 mol CO2/L at atmospheric pressure and 30℃,which was similar to that in pure CO2 absorption.A higher temperature would suppress the absorption capacity;3.025 mol CO2/L,however,was still observed at 50℃.The CO2 absorption capacity was still above 90.53%after four cycles of absorption and desorption.Such absorption systems of amino functionalized ionic liquid-aminewater presented good CO2 absorption performance and good perspective in industrial application,where the regeneration energy consumption was lowered due to phase change after absorbing CO2. |
