Study On The Selection Of Amine Solution Based On Thermodynamic Test For CO₂ Absorption

The increase of CO₂ in the atmosphere causes global warming,and lead to many environmental problems,whether the capture of CO₂ from flue gas in coal-fired power plants or purification of acid gas,organic amine is the most mature and developed faster method.In the process of carbon dioxide absorption by chemical absorption,the absorption of heat and regenerative energy consumption is an important index to evaluate the performance of absorbent.This paper adopts a CO₂ reaction heat measurement equipment was developed by Sinopec,The comparison between the experimental value and the literature value shows that the test device has good accuracy.The effects of temperature,concentration and CO₂ loading on the absorption heat of Hydroxyethyl ethylenediamine?AEEA?and ethanolamine?MEA?were studied.The results show that the absorption heat decrease with the loading and temperature increases,but the effect of concentration on the are not consistent,for MEA,the greater the concentration,the greater the heat absorption,AEEA is vice versa.The heat of absorption and desorption of AEEA were lower than MEA,the absorption heat and desorption heat range of AEEA are 65 ⁸0,90¹01k J/mol CO₂,respectively.The absorption heat a nd desorption heat range of MEA is 75⁹5,96¹09k J/mol CO₂.But the removal rate and absorption capacity of MEA were slightly higher.In the mass concentration of 20% of the AEEA,activators diethylenetriamine?DETA?,triethylenetetramine?TETA?,tetraethylene pentamine?TEPA?,n-methyldiethanolamine?MDEA?,diethanolamine?DEA?,piperazine?PZ?,2-amino-2-methyl-1-propanol?AMP?were used to form the binary mixed amine system with different concentrations of 1⁵% by mass.The absorption heat,desorption heat,absorb capacity,and removal rate of the mixed amine were measured to explore,the results showed that the effect of 20% AEEA + 4% MDEA was the best,the absorption heat was 62.61 k J/mol CO₂,the desorption heat was 78.5 k J/mol CO₂,the absorption was 18.6L,the desorption rate was 74.79%.Use it as the mainabsorbent of ternary mixture to continue research,ternary complex experiment on the basis of the two were added MEA,DEA,DETA,hydroxyethylpiperazine?AEP?,PZ,It was found that the reaction heat of the ternary complex solution was lower than that of the same AEEA reaction heat,but higher than the reaction heat of its base solvent?20%AEEA+4%MDEA?,and the removal rate is generally low,indicating that the reaction between the ternary mixed amine is more complicated.Where PZ may have a negative interaction with AEEA + MDEA and is therefore not suitable for use as an activator for this absorbent system.Finally,the absorbance of 20% AEEA+4%MDEA+3%AEP was selected by the analysis of each parameter,The calculation equation of the absorption heat of the absorbent at different absorption temperatures is obtained by curve fitting.And the comparison between the experimental value and the literature value shows that the test device has good accuracy.CO₂ continuous capture experiment use 20%AEEA+4%MDEA to test,the results shows that Under the optimum operating parameters,the minimum energy consumption of 20% AEEA+ 4%MDEA is3.2MJ/kg,and compared with the domestic 4⁵GJ/t regeneration energy consumption,reduced about20³6%.The preferred two amine solvent has gained good capture effect and good regeneration effect,has very high industrial application value.