Online Monitoring Of The Key State Variables And Optimization Of Soot Blowing For Coal-fired Power Plants

At present,about two-thirds of China's electricity supply relies on thermal power.On-line monitoring and operation optimization of coal-fired units still have many difficulties to overcome.Technological progress and the development of high-parameter coal-fired units are the primary ways to improve the energy efficiency of thermal power units.However,regardless of the type of unit,advanced operation optimization schemes and control technologies can further improve the energy efficiency of coal-fired power stations and reduce the coal consumption level of the unit.Aiming at energy-saving and consumption-reducing of coal-fired units,this paper carries out research on mechanism modeling of boiler side of coal-fired units,real-time estimation of flue gas temperature at furnace outlet and optimization method of soot blowing.(1)Based on the heat transfer and operation mechanism of the boiler side subsystem,the mechanism model of the main heating surface and the energy compensation model of the metal wall on the boiler side of the coal-fired unit are established.The calculation methods of various heat losses are summarized.(2)On the basis of the mechanism model of the heating surfaces on the boiler side,a method for real-time estimation of the average flue gas temperature at furnace outlet is proposed,in terms of dynamic mass and energy balance of the working fluid.On-line simulation validation using historical operation data of actual units is proposed.(3)The boiler side heating surface is divided into three categories,and the soft-sensing models of ash condition are established for the three types of heating surface.On this basis,aiming at maximizing the benefit of soot blowing,the time and frequency of soot blowing are optimized,and the strategy of soot blowing is given,which can provide reference for operators to optimize soot blowing and improve the operation efficiency of coal-fired units.(4)Using mainstream software development technology,a real-time monitoring and soot blowing optimization system platform for coal-fired power plants is developed.The system can realize real-time interaction with DCS system,on-line monitoring of key variables at boiler side,human-computer interaction based on B/S mode,soot blowing monitoring and optimization,etc.