Study On Static Characteristics Of Circulating Fluidized Bed Boiler

Circulating fluidized beis a clean coal combustion technology has many advantages which are high combustion efficiency,low pollution,wide adaptability of fuel and large range of load change.Although the circulating fluidized bed(CFB)boiler has been put into commercial operation,but when the load changes,there will be "overshoot" and "reverse" phenomenon resulting in turbulence adjustment of automatic generation control(AGC).Because of the characteristics of the combustion system of large thermal inertia and strong coupling,the static and dynamic characteristics is extremely complex.In order to the circulating fluidized bed boiler automatic control is difficult,the problem of stable and efficient operation of circulating fluidized bed boiler is serious.The problem seriously affects the stable and high efficiency operation of CFB boiler.In view of the above problems,this paper takes 350 MW CFB boiler as the object of study,and studies the static characteristics of CFB boiler.The research results are universal for CFB boilers with different capacities.First of all,the coal of Hepo quality data are obtained by experiments.And Hepo coal,Shuozhou coal,Pingshuo mixed coal,Inner Mongolia lignite,Zhengzhou bituminous coal are compared on broken characteristic,ash wear characteristics and combustion characteristics.Secondly,it builds material balance model and energy balance model and mass balance modelthe based on gas solid flow of circulating fluidized bed boiler.Static optimal operation amount is given which is include the quantity of coal,primary air,secondary air flow and discharge amount of two,and gives the boiler fly ash carbon content,carbon content in the bottom ash and the boiler heat efficiency.Finally,the static characteristic calculation software of CFB boiler is developed.It is includes CFB boiler design parameter module,coal quality module,limestone characteristic module,initial bed particle size distribution module,optimization module and calculation result output module.The software can realize the calculation and optimization of each static parameter.Useing the 350 MW circulating fluidized bed boiler of Hepo as the research object,it analysis coal particle size,fluidization velocity,bed pressure drop on the separator efficiency and influence of furnace material concentration distribution.The efficiency and the thermal efficiency of the boiler combustion optimization was calculated using optimization module.The study of static characteristics of CFB boiler can provide technical support for optimal operation of design and operation personnel,and lay the technical foundation for combustion decoupling control of CFB boiler.