| With the development of modern industry,the demand and consumption of fossil fuels such as coal,oil and natural gas are constantly increasing.However,due to the use of fossil fuels,the concentration of CO2 in the atmosphere has increased significantly,leading to many serious environmental problems such as the greenhouse effect and melting of glaciers.In recent years,how to reduce CO2 emissions has become an urgent problem for all mankind.At present,the most widely used CO2 capture method in industry is the Alcohol-amine method,but the Alcohol-amine method also has some defects:the alcohol amine is volatile,corrosive to equipment,prone to thermal degradation and oxidative degradation,and has high energy consumption for regeneration.Therefore,it is particularly important to develop a new generation of CO2 capture technology.As a new generation of green solvent,the deep eutectic solvents have the advantages of high thermal stability,not volatile,and strong environmental friendliness.It is expected to replace the traditional CO2 capture technology.This paper discusses the synthesis of six deep eutectic solvents:p-cresol/ethanolamine,p-cresol/diethanolamine,p-cresol/N-methyldiethanolamine,p-chlorophenol/ethanolamine,p-chlorophenol/diethanolamine and p-chlorophenol/N-methyldiethanolamine.In order to solve the problem of high viscosity of deep eutectic solvents,six deep eutectic solvents were dissolved in water to form a deep eutectic solvent-water system.The CO2 absorption performance of each absorbent under different conditions was measured by the weighing method.The experimental results show that for the six pure deep eutectic solvents,p-cresol/ethanolamine has the highest CO2 absorption capacity,and its CO2 absorption capacity is 0.126g CO2/g absorption,which is higher than 30%wt ethanolamine aqueous solution(absorption capacity is 0.12g CO2/g absorption),and the level of CO2 absorption capacity follows the rule:p-cresol/ethanolamine>p-chlorophenol/ethanolamine>p-cresol/diethanolamine>p-chlorophenol/diethanolamine>p-cresol/N-methyldiethanolamine>p-cresol chlorophenol/N-methyldiethanolamine.For the six deep eutectic solvents-water system absorbents,it was found that the absorbent absorbs CO2 and separates into phases,and CO2 is enriched in one of the phases,which is caused by the generation of hydrophilic ammonium salt in the absorption system.Among them,50%wt has the best CO2 absorption effect on cresol/ethanolamine(molar ratio 1:1),and when the type of Alcohol-amine is the same,the absorption amount of CO2 in the absorption system containing p-cresol is always higher than that Absorption system.Compared with the traditional 30%wt ethanolamine aqueous solution,50%wt p-cresol/ethanolamine(molar ratio 1:1)reduces the concentration of ethanolamine and the water content of the system.In addition,the regeneration solution needs only half of the original when desorbing,which has certain potential in reducing energy consumption.For the above absorbents,the effects of temperature,composition,water content and other factors on the absorption of CO2 by the absorbents were investigated.The experimental results show that high temperature and hydrogen-bonded donor are p-chlorophenol,which are not conducive to the absorption of CO2 by pure deep eutectic solvents;High temperature,hydrogen bonding donor is p-chlorophenol,low proportion of hydrogen bonding donor and acceptor,and low water content are not conducive to the absorption of CO2 by the deep eutectic solvent-water absorption system.This article measured the recovery and regeneration of the absorbent after it absorbed CO2.After 5 times of regeneration,the regeneration efficiency of the absorbent was still close to 90%,which proved that it had good recyclability. |
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