Carbon capture

utilization and storage technology is an important way to realize the carbon peaking and carbon neutrality goals in China. Among them

the non-aqueous phase absorbents have great energy-saving potential

and it is suitable for the existing mixed amine reactor

which has a large development potential.However

there are still problems such as high viscosity of CO_2 saturated solution and low circulating load. In this regard

a non-aqueous absorption system with low viscosity and regeneration temperature was constructed using secondary amine MCA as the absorbing component and EG as the organic solvent. The absorption and regeneration performance of MCA/EG was investigated. The results showed that

the absorption load of 3 mol/L MCA/EG solvent was up to 2.14 mol/L

and the viscosity was only 44.19 m Pa·s. Under the condition of absorption at 40 ℃ for 30 min and regeneration at 80 ℃ for 25 min

the cyclic load was as high as 0.98 mol/L

which is 1.46 times of the cyclic load of 30% MEA/H_2O solution at 105.5 ℃. The reaction heat of the absorbent was measured to be-82.85 kJ/mol by C80 microcalorimeter

which was lower than that of the MEA/H2O solution. The reaction mechanism of CO_2 capture by MCA/EG was explored by ~(13)C NMR and quantum chemical calculations. It was found that the stability of the reaction products was reduced for the steric hindrance effect of MCA. The carbamates transform into alkyl carbonate by reacting with EG to realize the regeneration at low temperatures. MCA/EG can realize the stable operation of non-aqueous phase absorbent and expand the scope of waste heat utilization in absorbent regeneration

which has a great advantage of energy reduction.