| The system of integrating solar thermal energy into conventional power plant is named as solar aided coal-fire power generating system (SACFPGS). For the purpose of saving energy, such system could substitute for part of coal consumption or all of them. Since the technology of parabolic trough solar concentration is much more mature than others and its parameters are also appropriate for integrating with coal-fired power plant, the parabolic trough solar aided coal-fired power generating system has been explored in this paper. Moreover, the efficiency of energy conversion, the contribution of solar and the control mode of operation have also been investigated.The performance and the operation mode of parabolic trough solar aided coal-fired power generating system have been researched in this work. Based on modeling and simulating the system, the qualitative and quantitative analyses have both been presented. The main contents of the thesis are as follows:Firstly, the dynamic models of coal-fired power generating system and solar heat concentration system have been built and simulated. The accuracy of the models have been verified. The simulation error within an narrow range could satisfy the demand of dynamic and static state operation performance research. On the basis of these, the SACFPGS model with and without thermal storage system have been constructed.Secondly, the exergy analysis of solar aided coal-fired power plant has been carried out. The effect of irradiation intensity and load variation are analyzed for confirming the distribution of losses. By comparing the exergy analysis result of SACFPGS with the solar thermal power generating system, it’s found that the utilization rate of solar energy is significantly improved.Moreover, the method of determining the contribution of solar energy in SACFPGS has been built. The percentage of solar energy in each exergy flow, the energy cost of exergy flow and the cost percentage of solar energy in each exergy are calculated. According to the sensitivity analysis, variation trend of power generation cost and solar contribution with coal and device prices have been achieved.Lastly, the operating mode of SACFPGS with thermal storage has been explored. According to operation states of coal-fired power generation side and solar side, the flow rate of the concentration system, thermal storage system and heat exchanging system are regulated reasonably for ensuring the steady operation of coal-fired power generation system. Based on these, the high pressure water heater will not be switched frequently and the service life of device will be extended. |
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