Economic Analysis Of Solar Thermal Field And Coal-fired Unit Integrated System

With the integrated system of solar thermal field with 600MW supercritical coal-fired unit as the research object,the calculation models of various integrated schemes are established.Under the condition of fixed irradiation,the thermal economy is discussed and the best scheme is obtained.The characteristics under variable irradiation conditions of the optimal scheme are analyzed and technical and economic analysis is conducted.Under fixed irradiation conditions,the thermal economy analysis of parallel connection between heat collection system and heat recovery system is carried out.The results show that:parallel connection between solar energy and high-pressure feed water heaters is the best scheme,which has the maximum thermal-electricity conversion efficiency and investment and coal saving ratio.As to another two schemes in which the feedwater are led from the front pump outlet and the deaerator inlet,the results show that when the feedwater is led from the front pump outlet to generate solar steam to replace the first segment extraction steam is the best.Characteristics analysis under variable irradiation conditions of the above-mentioned two schemes are conducted.Taking the two regions of Lhasa and Hohhot as examples,the technical and economic analysis of the above two schemes show that in whatever scheme,in Lhasa,where the solar energy resources are more abundant,the integrated system is more effective in saving coal and reducing CO₂ emissions,with smaller LEC and shorter payback period.The analysis of the factors affecting LEC and payback period show that the cost of collectors has a significant impact on LEC and payback period:when it is reduced to 1000?/m²,the LEC of the two schemes in Lhasa are reduced to 0.39?/?kW?h?and 0.29?/?kW?h?respectively,the payback period decreased by 39%and 43%respectively.Further reducing the cost of the collectors,extending the service life of the equipment,and building the integrated system in areas with higher irradiation intensity are ways to reduce costs and shorten the payback period.