Research On Control Model Of Once-through Boilers Based On Dynamic Heat Storage

In recent years, the development of new energy power generation is in full swing, but in our country, the thermal power is still dominant in the electric power production stracture. At the same time, our country’s primary energy structure determines the thermal power unit in China is mainly using coal as fuel. As the environmental protection and energy conservation and emissions reduction requirements is higher and higher, thermal power unit withing large capcity and high parameter will be a trade, and supercritical and ultra supercritical once-through unit is more and more commonly. So the large capacity once-through unit must be further research, and design a suitable model witch can be used to establish control systems is premise. In order to achieve the above purpose, following work has been finished:1.To analyze the supercritical once-through boiler heat storage. Using mechanism analysis method to calculate the specific enthalpy and pressure’s distribution with the change of the height of furnace of working medium in water wall, based on the IAPWS-IF97 standard partition, devide water wall into three part. Then using the law of conservation of mass and the law of conservation of energy, deduced the computational formula of water wall and superheater heat storage. At last, using the design parameter of Jianbi electric powe plant finished the calculation of heat storage. Through the analysis of the heat storage date, got such a conclusion:tower type once-through boiler water wall heat storage and superheater heat storage is roughly equal, and metal heat storage is much more than working meduim heat storage, so the boiler heat storage can be replaced by metal heat storage.2.The once-through boiler unit was divided into the coal pulverizing system, boiler and steam turbine system, then using mechanism analysis designed these three system’s model, then introduce metal heat strage to amended the model which suit to estabish control systems. At last, using historical operating data of Jianbi electric power plant 14 unit obtained the parameters.3.Comparing model output values and unit measured values, verfied the accuracy of the model. Got four typical working condition by K-means clustering algorithm, and calculated the liner model at these four typical working condition by small deviation linearization method. At last, establish a gain scheduling controller for model, and through the experimental results show the effectiveness of the controller.