Waste heat recovery and cascade utilization of CO2 chemical absorption system based on organic amine method in heating season

•Recovered waste heat from humid flue gas and solution of CO2 capture system.•Achieved energy conservation, CO2 and pollutant emission reduction effect.•Two-stage gas waste heat recovery can improve boiler efficiency by over 19%.•Cascade recovered over 80% of the solution regeneration energy consumption. In this paper, we proposed a waste heat recovery route of CO2 chemical absorption systems, which can realize waste heat recovery and cascade utilization in heating season. Simulation methods were used to study carbon capture systems and absorption heat pump, experimental methods were used to study the contact heat transfer characteristics of packed tower, and three organic amine solutions were involved: MEA (2-Aminoethanol), MEA& MDEA (N-Methyldiethanolamine) and AMP (2-Amino-2-methyl-1-propanol). The outlet gas temperature of carbon capture system is 47.7 °C∼58.8 °C, the temperature of lean solution is 73.3 °C∼95.0 °C, the absorption heat pump can increase the return water from 40 °C to 85 °C∼97 °C, the heat transfer end difference between flue gas and water in packed tower can be less than 1.0 °C. The system can achieve energy conservation and CO2 emission reduction effect, over 80% of the solution waste heat were recovered, the two-stage gas waste heat recovery process can improve boiler efficiency by over 19%.