The Establishment And Simulation Analysis For Core Model Of Ultra-supercritical Unit

With the development of boiler to the direction of the high-capacity and high parameters, ultra-supercritical unit has become a major thermal power unit in our country. However, domestic scientists still lack sufficient experience for the design, manufacture and operation of the ultra-supercritical unit, and in-depth understand to the dynamic characteristics of the unit, which also brings the corresponding problem for the design of control system and debugging. Therefore, in-depth study and mastery for the dynamic characteristics of ultra-supercritical unit, and the study for operation control technologies to improve unit performance base on the understanding to ultra-supercritical unit, have important practical significance.On the terms of modeling, the focus of the current simulation model is the establishing of water cooled wall model which is a simple, applicable to real-time simulation model, and which also can fully reflect the dynamic characteristics of system. This paper takes a combination method of mechanism analysis and data analysis to method, to create the nonlinear lumped-parameter moving boundary mathematical model of water cooled wall, based on specific features of1000MW ultra-supercritical once-through boiler in Taizhou power plant. Then carries out the step disturbance experiment, the simulation results describe the dynamic characteristics of water cooled wall under two typical operating conditions including60%load and100%load.On this basis, this paper further adds the separator model, single-phase heating surface model, the furnace and flue gas side model, and the simplified model for steam turbine, to form a simplified integrated model for ultra-supercritical unit which is suitable for the large disturbance dynamic simulation. Then this paper carries out simulation study for dynamic characteristics under typical operating conditions. And the validity of the model has been initially verified.This model can be used to conduct a comprehensive assessment and analysis for the main dynamic characteristics of unit, and also makes good foundation for the mastery of opration performance for the whole unit and the improvement for control method.