A polygeneration system for methanol and power production based on coke oven gas and coal gas with CO2 recovery

Abstract

Polygeneration system for chemical and power co-production has been regarded as one of the promising technologies for fossil fuel sustainable utilization. In this paper, a new polygeneration system with carbon capture is integrated, based on coal gas and coke oven gas inputs for methanol and power co-production. New system can achieve more than 5% of primary energy saving ratio, and more than 50% of exergy efficiency. Exergy balance and Energy Utilization Diagrams (EUDs) are applied to show the performance improvement. In the system, pressure swing adsorption process is used to remove hydrogen from coke oven gas to enhance methane concentration, which reduces energy consumption and exergy destruction of reforming process. And for the methane reforming process, thermal energy for reforming is sensible thermal energy of syngas out of gasifier instead of fuel gas combustion. Furthermore, fresh syngas for methanol synthesis is the mixed gas of reformed coke oven gas and coal gas, which means that syngas components are adjusted without energy consumption. Lastly, CO2 is recovered during chemical energy discharge and at the highest concentration resulting in less energy penalty. All of these energy integrating characteristics result in good thermal performance, which supplies a new direction for clean energy technology.