CO 2 Capture and Utilization in Power Stations for Power-Heat-Methanol Polygeneration

This study presents a novel polygeneration configuration for simultaneous power, heat, and methanol generation, with integrated CO 2 capture and utilization. The configuration builds upon a decarbonization power station, where captured high-purity CO 2 is used as feedstock for methanol synthesis via CO 2 hydrogenation. Furthermore, deep integration is implemented, enabling fully recoverable heat from both decarbonization and hydrogenation processes, to maximize overall thermo-economic performance. On the basis of a systematic retrofit of a typical 300 MW power station, thermodynamic assessment indicates that the proposed configuration converts coal (31.3 kg/s) and hydrogen (4.38 kmol/s) into 117.9 MW of power, 333.5 MW of heat, and 40.6 kg/s of methanol. Recoverable heat accounts for 66.6% of the total heat generation, while methanol conversion reaches 78.2%. Economic assessment shows that the gross cost of power generation (CPG) of the power section is increased from $38.8/MWh (reference) to $116.6/MWh, due to the decreased power generation and increased total investment. Nevertheless, the net CPG of the proposed configuration is reduced to $77.8/MWh, as the economic gains from the heating subsystem offset the gross CPG. By utilizing CO 2 feedstock, power for gas compression, and heat for methanol distillation from the power station, the cost of methanol generation (CMG) of the methanol section is reduced from $1141.2/t (reference) to $1005.6/t, demonstrating strong economic competitiveness for industrial deployment.