| As a new energy source,solar energy is not only widely distributed,but contains a lot of energy.Its use directly affects China’s environmental protection cause and the direction of energy structure transformation.Research on the operation optimization of the integrated solar photovoltaic combined cycle power generation system(ISCC)can not only alleviate the randomness,volatility and intermittency of individual solar operation,but also effectively improve the power generation efficiency of the solar thermal system,which has an important impact on the utilization and development of solar technology.The variable operating characteristics of the gas-steam combined cycle system were studied,and the solar module was added to form the ISCC system on this basis.In order to find the best integrated solution for solar heat and achieve the reasonable utilization of solar heat,the impact of external environment changes on the operating characteristics of the ISCC system,as well as the changes in the thermal performance of the system under different integration methods were deeply analyzed.The main research contents of this article are as follows:Taking the traditional gas-steam combined cycle as the basic system,the combined cycle thermal system model is constructed and simulated by Ebsilon software,and the simulated data is compared with the design data under various working conditions.The results show that the error between the simulated value and the design value is within 3%,which is the allowable range of engineering error,which verifies the accuracy of the model.Under heating conditions,the built-up gas-steam combined cycle system was simulated and studied under variable conditions,and the performance change law was obtained.Firstly,the influence of ambient temperature on the performance of gas turbine and combined cycle system is explored.The analysis shows that the combined cycle system at 48.2℃ has the highest operating efficiency among all temperature conditions.When the heating load increased from 0 GJ/h to 800 GJ/h,the heat consumption rate of the combined cycle unit under this operating condition decreased by 2014.45 kJ/kW·h.Secondly,the influence of different gas turbine load rates on the gas-steam combined cycle system was analyzed,and the changing rules of the combined cycle system under variable operating conditions were summarized.The research shows that as the extraction coefficient raises,the operating efficiency of the system increases under certain conditions of the gas turbine load rate.In order to maximize the operating benefits of the combined cycle unit,the unit should be operated at 100%of the gas turbine load and the maximum heating load.Based on the analysis of the typical summer solstice solar power generation capacity and the overall ISCC system performance changes under the design conditions,the annual system operating characteristics are summarized for the optimization analysis of the ISCC system.The analysis shows that the solar photovoltaic conversion rate is 33.31%and the solar thermoelectric conversion rate is 31.12%,which are much higher than that of traditional solar thermal power plants.The total annual power generation of the ISCC system is 3682.64 GW,and the annual generating capacity of the CSP system is 45.42 GW,accounting for 1.23%of the annual electricity generation.On this basis,the best heat utilization method of solar energy is explored,the solar photovoltaic conversion rate and the overall system thermal performance change under different heat collection schemes are compared.And the advantage data of solar power generation share 11.43%,solar input share 16.28%,and ISCC system cycle efficiency 47.03%were determined as the optimal heat collection scheme of solar heat.Finally,the issues of gas sources and carbon emission reductions were discussed preliminarily,and four plans were developed to compare and calculate methane consumption,carbon emissions,and the cost of using renewable energy for electricity generation for methane generation. |
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