Control-oritented Object Performance Analysis And Identification Of Once-through Boiler Steam Temperature

The thermal system of power plant is an important application area of simulation technology. The modern power plant is very complicated, the production process is highly automated, the technical indicators are very strict, the production not only need highly reliable, but also need economic. In order to make sure of the security and the economy of the thermal system in production, during its designing, producing, debugging, controlling, technical improvement, managing, science researching and personnel training, simulation technology will be used. Currently, the application of simulation system concentrated mainly on the training of operation staff, the analyzing of operating performance, and the evaluating of control performance of generation unit.Through efforts for several decades, a great many of research results have been accumulated in the field of modeling and simulation technology of thermal system in the power plant, particularly in the research of dynamic mechanism model of thermal system. Because of the complexity of the model itself, the above mechanism model would be difficult to be used to design the control system of units directly.In this paper, taking one 1900t/h supercritical pressure once—through boiler as subject investigated,the main work contains as follows:①According to the tracing view of material point, a distributing parameter model of heat exchanger is established on the current basis. And other simulation models of boiler system are added, these models Include water separator, water temperature and boiler combustion devices, etc. These constitute the simulation model of the reality boiler system.②The primary dynamic performance of boiler system is simulated, meanwhile, the outlet temperature response properties of the boiler's various links have been obtained under different load and work pressure(supercritical pressure and subcritical pressure), and the main nonlinear features of system are examined.③Due to the above mechanism model would be difficult to be used to design the control system of units directly, the object identification model is established based on the simulation results and the transfer functions of boiler system under different load are gained with area method, and the ability of describing has been tested.The above work has laid a good foundation for further design of control system of boiler.