A novel design has been developed in this study to enhance the efficiency of methanol synthesis through integration with an MEA-based decarbonization coal-fired power plant based on cascade utilization of chemical and thermal energies. The cogeneration system

with carbon capture technology as the link

synthesizes methanol from green hydrogen produced from renewable energy sources and CO2 captured from coal-fired power plants. It coordinates the overall process of low-temperature waste heat reuse

purge gas utilization

and carbon element recycling

realizing complementary utilization of different energy qualities and coordinating enhancement of different subsystems. The results show that the primary energy utilization of the methanol synthesis process in the cogeneration system increases by 12.18%

the carbon capture energy efficiency penalty in the coal-fired power generation process decreases by 1.98 GJ/(t·CO2)

and the overall efficiency of the cogeneration system increases by 2.30%. The net present value for the entire life cycle increases by 560 million RMB

the dynamic payback period decreases by 1.2 years

and the production cost of low-carbon methanol has been reduced by 321.8 RMB/t. When the price of green hydrogen is below 20 RMB/kg

the methanol produced by the cogeneration system has a significant competitive advantage compared to petroleum. Under conditions of providing equal amounts of electrical energy and chemical energy

the fossil energy consumption of the cogeneration system decreases by 59.7%

and carbon emissions decrease by 46.5%.