Experimental Study On CO₂ Absorption Based On MEA-organic Solvent-water System

Global warming and greenhouse effect have become the hot issues of global concern.CO2 is the most prominent gas that contributes to the greenhouse effect,and its capture technology is improving day by day.However,most of the current researches on CO2 absorbents focus on reducing the energy consumption of capture,reducing capture and integration,and there is still a lack of studies on the dynamics and thermodynamics of absorbents.In the previous period,this group undertook a systematic experimental study of MEA-based and MDEA-based absorbents,and screened out an absorbent that has high absorption rate and low desorption energy consumption.However,the previous experiments did not study the kinetic factors of the absorbent,and the theoretical guidance of the latter experiment was limited.Therefore,in this dissertation,the kinetics of sorbents was explored.The effects of different alkanolamines,different types of organic solvents,and different ratios on the initial absorption rate of absorbents were investigated.At the same time,a high absorption rate and high absorption rate were selected.The ability of absorbents to examine the effect of different organic solvents on the solubility of CO2 in absorbents.In this dissertation,the initial absorption rate of the absorbent was measured by a mass flow meter,and the solubility of CO2 in the absorbent was measured by stirring the reactor to perform kinetic and thermodynamic experiments.It was found that the addition of organic solvent can change the initial absorption rate of 30%ME A.The addition of most organic solvents can promote the initial absorption rate of 30%MEA.Among them,ethanol has the most obvious effect on the initial absorption rate,30%MEA-35 The initial absorption rate of the ethanol-35%aqueous system was 0.0644 mol CO2/mol amine min-1,which was 88.9%higher than that of the 30%MEA.The concentration of organic solvent also has a significant effect on the initial absorption rate of 30%MEA.For short-chain alcohols(methanol,ethanol,n-propanol),the initial absorption rate of the absorbent increases significantly as the solvent concentration increases;for longer-chain alcohols(n-butanol),the absorption rate increases as the concentration increases.The degree of improvement is reduced.The effect of the ratio of the absorbent on the initial absorption rate showed a trend of increasing first and then decreasing.When the concentration of dioxane was 30%,the initial absorption rate reached a maximum of 0.0654 mol CO2/mol amine min-1.91.8%.In addition,for the thermodynamic experimental study,we found that the addition of organic solvent will reduce the solubility of CO2 in the absorbent,and the length of the alcohol chain also has an effect on the solubility of CO2.The longer the chain,the greater the solubility of CO2 in the absorbent.The concentration of the organic solvent has a significant effect on the solubility of CO2 in the absorbent.The solubility of CO2 in 30%MEA decreases with the increase of organic solvent concentration,and decreases with the increase of the organic solvent ratio in the absorbent.