660 MW超超临界直流锅炉水冷壁系统动态特性仿真

通过机理分析和合理简化,建立了某电厂660 MW超超临界直流锅炉水冷壁系统的非线性移动边界动态数学模型,并对该锅炉在75%热耗率验收(Turbine Heat Acceptance,THA)工况和额定(Boiler Rated Load,BRL)工况下水冷壁系统的动态特性进行仿真,结果表明:各种扰动下水冷壁系统各参数的变化趋势均能通过机理分析给予合理解释;在不同的扰动输入下,水冷壁系统各参数的动态特性各异;当75%THA工况时,在进口焓值阶跃扰动下,蒸发段长度的动态响应存在超调;当75%THA工况和BRL工况时,在进口焓值阶跃扰动下,出口蒸汽比焓在其响应初期都存在逆向变化过程。研究工作加深了对660 MW超超临界直流锅炉水冷壁系统动态特性的认识,可为优化该型锅炉的设计、控制和运行以及电站仿真机的开发提供理论参考。

Dynamic Characteristics Simulation of the Water Wall System of a 660 MW Ultra-supercritical One-through Boiler

Based on the mechanism analysis and reasonable simplifications,a nonlinear dynamic mathematical model with moving boundaries for the water wall system of a 660 MW ultra-supercritical once through boiler is established,and the dynamic characteristics of the water wall system are simulated under the 75% THA (Turbine Heat Acceptance) and the BRL (Boiler Rated Load) working conditions,respectively.Simulation results show that: the trend of the parameters of the water wall system under various disturbances can be reasonably explained by the mechanism analysis,and the dynamic characteristics of each parameter of water wall system are different under different disturbances.For the 75%THA working condition,the dynamic response of the length of evaporation zone is overshot under the step disturbance of inlet enthalpy.Under both 75% of THA and BRL working conditions,the dynamic response of the specific enthalpy of outlet steam has a reverse change process at its initial stage under the step disturbance of inlet enthalpy.The work of this paper is expected to deepen the understanding on the dynamic characteristics of the water wall system of a 660 MW ultra-supercritical once through boiler,and lay a good foundation for optimizing the design,control and operation of the boiler and the development of a power station simulator.