Experimental Investigation Of Amine Solution Characteristics In CO₂Capture System From Power Plant

Alcohol amine solution is widely used in CO2capture from power plant, nevertheless, there are some problems,such as low absorption efficiency, high desorption energy consumption and tremendous equipment, which seriously restrict the promotion of CO2capture technical. In this paper, experimental study of absorbent performance was carried out to screening and optimizing high-performance absorbent, which is high absorption efficiency, low desorption energy consumption and anti-degradation, in order to reduce the CO2capture cost effectively.As representative solution, MEA, DEA, TEA and AEE were selected for experiment. The characteristics of the solution, such as absorption rate, desorption rate, the pH value of the solution, the degree of regeneration, reaction time and CO2absorption capacity were analyzed.Measured results indicated that absorption rate decreases along with the reaction progressing, which decreases rapidly in the first30minutes and then decreases gently. The sequence of absorption rate from high to low is AEE, MEA, DEA and TEA. The pH of solutions declines along with absorbing and the pH of TEA declines more rapidly than the other solutions in the first25minutes.Experimental device was built to measure desorption energy consumption of several kinds of absorbent, which focus on the relationship between desorption rate, the degree of regeneration reaction time and CO2absorption capacity. Measured results indicated that instantaneous desorption energy consumption changes significantly along with the reaction progressing, which present the trend of degressive-mild-elevatory. Under the same testing condition, the desorption energy consumption of AEE is the lowest in the first40minutes and the desorption energy consumption of MEA is the highest.The desorption energy consumption of four kinds of absorbent in different concentration has no evident difference and the instantaneous desorption energy consumption maintained at7～15GJ/tCO2in50～85min. The desorption energy consumption of all kinds of solution increased rapidly at the last paragraph of the desorption reaction. Desorption rate increase with the growth of solution concentration and the desorption rate-time curve presents a typical increase-decrease parabolic trend.The sequence of desorption rate from high to low is AEE, DEA, TEA and MEA. The trend of regeneration degree presents mild-severe-mild and the degree of regeneration of TEA can reach90%which is higher than others.The experiment of multiple circulated absorption-desorption characteristics was carried out. Measured results indicated that the absorption and desorption rate of traditional absorbents is familiar, whereas AEE absorption rate decreased significantly with cycle index increasing. The sequence of desorption energy consumption variable from high to low is MEA, DEA, TEA and AEE.