Simulation And Performance Study Of Solar-gas Combined Cycle Power Plant

Currently,the energy structure of China is still dominated by the coal-fired power.In order to reduce the dependence on fossil energy and control the environmental pollution caused by coal-fired power,the development of sustainable clean energy will be the future direction of energy utilization.Solar energy is an inexhaustible clean energy,which has very broad development prospects.Solar thermal power generation has been developed to different degrees all over the world.But due to the discontinuity and instability of solar energy,the large-scale commercial application of solar energy has been hampered.The core equipment of gas-steam combined cycle(GTCC)is the gas turbine.The gas turbine can operate stably,but it is greatly affected by environmental factors.In order to improve the thermal efficiency of gas-steam combined cycle,the exhaust gas temperature of waste heat boiler should be reduced as much as possible in a certain range.The utilization of a single energy is hindered by many factors.Therefore,in the future development process,the complementary integration of multiple energy sources is becoming a major trend.In this paper,a new kind of integrated solar-gas combined cycle(ISCC)power plant is proposed.The studies of the system design,power plant modeling and optimization,performance analysis and comprehensive evaluation for this ISCC power plant are launched,aiming to provide theoretical reference and new ideas for the research and development of solar-gas combined cycle power plant.The main contents of this paper are as follows:Firstly,based on the system flow,parameter design and unit configuration,a new ISCC system is designed and the system model is established by using the EBSILON software.By the comparative analysis of operation simulation in different regions,the location of the ISCC power plant is selected.By using the SAM code,the solar direct steam system of the power plant is simulated.The scale of the collector field is optimized by comparing the average energy costs under different solar multiples.Secondly,eight different parameters are selected to simulate the operation of this ISCC power plant under varying conditions.The results reveal that the optimal ambient temperature is 10.0? for the operation of the ISCC system.With the inlet gas pressure loss(or the exhaust pressure loss)increased,the thermal efficiency of the ISCC system decreases.As the ambient pressure increases,the output power of the ISCC system increases but the variation of thermal efficiency is small.The influences of incident solar angle and air humidity on the ISCC system are both small.Smaller incident solar angle and greater air humidity can improve the performance of the ISCC system.The 50.0%,80.0%and 90.0%load factor operations of gas turbine should be avoided.Finally,the analyses of technical economy,environmental protection and energy saving of this ISCC power plant are conducted.The results indicate that the dynamic investment payback period of the power plant is 5.11 years and the internal rate of return is 19.46%,which reveals good technical economy.Two obvious influential factors for the technical economy are the prices of electricity and gas.Compared with other power stations,ISCC power station can effectively reduce the emission of air pollutants and save fuel.