Thermoeconomics Analysis Of Solar Aided Coal-fired Power Generation System

Solar aided coal-fired power generation system is the effective way to solve the problem of the environment and energy, which is integrating solar thermal energy into conventional power plant. So, reasonable evaluation of solar aided coal-fired power generation system is necessary for achieving optimal operation, and energy conservation and emissions reduction.The structure theory method in thermoeconomics was applied to the solar aided coal-fired power generation system, combined the different forms of solar energy system with a 350 MW unit system in different types. The thermoeconomic model of the unit was established with simplifying the solar energy system, dividing the whole system into components and definiting the fuel-product of each component. Calculated the unit exergy cost and the unit thermoeconomic cost of the tower solar energy aided coal-fired power generation system under the condition of design, variable radiation intensity and variable load. The formation process of the cost was analyzed and the results were compared with the traditional coal-fired system. Three types of systems were analyzed under the variable radiation intensity condition in this article, which were the tower solar energy system aided to the coal-fired system, the parabolic trough solar energy system parallelled with the low pressure heaters system and the parabolic trough solar energy system replaced the first stage steam extracted from the turbine.The results show that the unit exergy cost and the unit thermoeconomic cost of the integrated system were higher than the traditional system, but the coal consumption was lower. The higher the radiation intensity and the load were, the more the benefit got. The parabolic trough solar energy system replaced the first stage steam extracted from the turbine was better than the parabolic trough solar energy system parallelled with the low pressure heaters system. And under the condition of good radiation intensity, the coal consumption of the tower solar energy aided to the coal-fired system was lower than the parabolic trough solar energy system replaced the first stage steam extracted from the turbine. The dynamic analysis provided a reference to optimize the design and operation of solar aided coal-fired power generation systems.