Thermodynamic optimization and equipment development for a high efficient fossil fuel power plant with zero emissions

The transition to oxy-fuel combustion cycles is a perspective way to decrease harmful emissions into the atmosphere in the energy sector. The oxy-fuel, supercritical carbon dioxide Allam cycle (NET Power oxy-combustion cycle) is a promising technology with high efficiency. Emissions of carbon dioxide into the atmosphere could be decreased by 98.9% using this cycle for electricity production, which is 8–17% higher compare to gas turbine combined cycle with post-combustion carbon capture. However, there are several challenges on the way of its implementation, one of which is the development of a supercritical carbon dioxide gas turbine. The aim of the present study was to develop a construction of a high-power supercritical CO₂ gas turbine with optimal thermodynamic parameters of the Allam cycle and to evaluate technical, environmental and economic characteristics of zero emission technology for the electricity production. To reach the goal, the calculation algorithm allowing to model the oxy-fuel combustion cycles was developed. The results of thermodynamic optimization showed that the highest value of cycle net efficiency equal to 56.5% is achieved for the turbine inlet temperature and pressure of 1083 °C and 30 MPa, the turbine outlet pressure of 3 MPa and the coolant temperature of 200 °C. The formed equipment requirements were used to create the design of a 335 MW supercritical carbon dioxide gas turbine, the main features of which were described in detail. The results of environmental characteristics analysis showed, that the specific amount of CO₂ emitted from the cycle to the atmosphere is 0.0038 kg/kWh. The results of economic feasibility evaluation for the Allam cycle showed that the total specific investment costs including the price for carbon storage are equal to $1307.5/kW, which is quite competitive value.