Simulation Study On A Solar Tower Power System Integration Into A Coal-fired Power Plant

Solar energy is an inexhaustible, clean and renewable energy. Generation by solar energy is one of effective ways to solve the energy problem, protect environment and realize energy-saving and emission reduction. Introducing solar energy into the conventional power plant, and establishing a solar tower power system integration into a coal-fired power plant to realize solar aiding coal-fired generating, creates a new way of energy-saving of power plant. Without the installation of heat storage system of pure solar thermal power plant in the solar tower power system integration into the coal-fired power plant, the risks of system investment and corresponding investment are reduced. What’s more, the way of solar energy replacing part of coal-fired fuel to produce steam, saves coal consumption, and achieves energy-saving and emission reduction, and the adjustability of coal-fire unit be used to overcome the intermittent nature of solar energy. When the load of power grid is peak at noon, the strongest solar radiation can effectively improve the unit’s capacity of regulating load.In this paper, the operation scheme that tower solar boiler and power station boiler in parallel operate is adopted. Feed water from unit’ high-pressure heater outlet is leaded to solar thermal system. Qualified steam is mixed with the steam generated by power station, and enters into high pressure cylinder to do work. According to the operation law of heliostat field, the structure of tower solar system and fluid flow characters, the mathematical model of tower solar thermal system is established. Based on the simulation platform of STAR-90, the simulation system of tower solar thermal system is built. Meanwhile, connected with some 350 MW unit simulation system, the simulation model of the solar tower power system integration into the coal-fired power plant is built.Based on the model, the system operation is simulated, including the start-up, operation, and stopping. What’s more, the experiments about disturbance of radiation intensity,feed water flow and valve opening are performed. The results show that the model can well reflect system operation rules, both solar thermal system and thermal power generating unit. Moreover the dynamic characteristics variation is reasonable and effective. It can predict the change characteristics of the system. It is also found that solar thermal system operation have little influence on thermal power generating unit, and thermal power generating unit control system do not need to change a lot to realize the system normal operation.