Study On Thermal Characteristics Of Trough Solar Collector System Aided Coal-fired Unit Hybrid Power Generation System

Solar-coal hybrid power generation system is on the basis of traditional designframework for thermal power unit, a reasonable introduction of solar thermal powergeneration technology, that both is capable of increasing power output, improving solarthermoelectric conversion efficiency, and can reduce the amount of annual coal saving,the investment cost of pure solar power, so it is suitable for the energy-saving reformof existing power plant and the design of solar energy auxiliary power synchronouslywhen building new coal power plants, increasing share of renewable energy powergeneration, that has important value for industrial application in our country.This paper took the integration of the parabolic trough type solar heating systemand N300-16.67/537/537coal-fired unit as an example, firstly three integration modeswere presented, that were the steam generated by the solar collector directly accessingto the drum, replacing the steam turbine regenerative steam, directly accessing to thelow pressure cylinder of the steam turbine to work, then the technical economy of threeintegrated modes was calculated and compared through the application of variable heatequivalent enthalpy drop method theory, and combining with the actual application toselect the optimal integrated mode. Results showed that the optimal integrated modewhere the working medium from the exit of the condensate pump was heated to therequired steam parameters through the solar collector field and replaced1#high-pressure heater’s extracted steam.This paper carried out technical economic analysis to factors influencing system’sthermal performance such as region, class of unit capacity and design radiation intensity,and preliminary economic analysis to this kind of integrated mode, results showed thatthe technical economic performance of generating units in same capacity level was bestin the area whose total annual radiation was largest; for the same solar share, the greaterthe unit capacity was, the higher the solar thermal power generation efficiency, the solarthermal contribution rate and the coal consumption rate were, meaning the technicaleconomic performance of the unit was better; with the decrease of the solar radiationintensity, the technical economic indexes of the system such as solar thermoelectricefficiency and the solar thermal contribution rate got better and better, but the area ofthe collector field got bigger and bigger, meaning the investment cost of the collectorfield got higher and higher, so the comprehensive optimal performance of the system should lie a value between the maximum and minimum radiation intensity, in thehypothetical conditions of this article, the radiation intensity value as the design of theradiation intensity whose radiation time accounted for60%of the total availableradiation time was optimal.