Thermo-Economic Analysis of a Plasma-Gasification-Based Waste-to-Energy System Integrated with a Supercritical CO2 Cycle and a Combined Heat and Power Plant

Herein, a novel hybrid design that combines hazardous waste plasma gasification, gas turbine, supercritical CO2 cycle, absorption heat pump, and coal-fired combined heat and power (CHP) plant is proposed. In the integrated scheme, medical waste and concentrated solution of desulfurization wastewater are sent to the plasma gasifier and converted to syngas, which is conveyed into the gas turbine system after the necessary treatment. In terms of waste heat utilization of syngas and flue gas, some are used to drive the supercritical CO2 cycle, some are used by the absorption heat pump for heating, and the rest are used to heat the feedwater of the coal-fired CHP plant directly. Based on a typical coal-fired CHP plant, the benefits of this system are examined in terms of both thermodynamics and economics. Once the heat supply and the net electricity from coal remain the same, the net power generated by the waste in the hybrid design is 18.45 MW, while the net waste-to-electricity efficiency reaches 47.40%. In just 4.76 years, the initial investment in the proposed system is recouped, and in its 25 year lifetime, the system achieves a net present value of 150,491.81 k$.