Performance simulation on NG/O2 combustion gas and steam mixture cycle with energy storage and CO2 capture

A novel combustion gas and steam mixture cycle (GSMC) power generation system was simulated and studied in this paper. The system integrates the technologies of NG/O2 combustion, energy storage, peak-shaving and CO2 capture with LNG/LO2 cold energy utilization, which has remarkable features such as high efficiency, low first/operation/maintenance costs, zero CO2 and NOx emission and massive off-peak power shifting. A calculation case is presented and the impacts of turbine inlet parameters, condensing pressure/condenser outlet temperature and feedwater temperature on the net electric efficiency excluding ASU and equivalent net electric efficiency as well as CO2 capture features are analyzed. The steam content in vapor phase of the condenser outlet is considered which requires more cooling capacity for CO2 capture. Under the conditions that the condenser outlet temperature/condensing pressure is 30 °C/30 kPa and feedwater temperature is 300 °C, with fully CO2 capture, the net electric efficiency excluding ASU and equivalent net electric efficiency are 0.4386 and 0.4105 respectively with turbine inlet parameters of 600 °C/30 MPa, and they can reach 0.5327 and 0.5046 respectively with turbine inlet parameters of 1000 °C/40 MPa.