The Research Of Numerical Simulation On Effect Of Coal Characteristics On Hedge Flame Boiler Combustion

In our country, power station boilers give priority to coal-fired boilers,but thecoal resources maldistribution and high cost,lead to substantial power station boilershave low quality coal,these problems has brought great influence on safe andeconomic operation of power station boilers. Therefore, researching on the effect ofcoal characteristics to the boiler operation is very important to improve the efficiencyof coal and realize the optimal operation of the boilers. Basing on the analysis of coalcombustion characteristics, the effect of coal characteristics on combustioncharacteristics of hedge flame boiler was investigated with the method of numericalsimulation.At first, this paper introduced the development of hedge flame boilers at homeand abroad, analysed the advantages and disadvantages of this kind of boilers in thestructure and operation, and compared with other kinds of boilers, sumed up the betterplace for the better development. The next, introduced the physical and mathematicalmodel and theoretical basis which belong to the numerical simulation of pulverizedcoal burning. In the chapter four of this paper, mainly intoduced the specific situationwhen simulating the 660MW hedge flame boiler operating. Meshed by the processingsoftware-Gambit which belong to FLUENT, then set the boundary conditionsaccording to the parameters of power plant. By analyzing the velocity field，temperature field，oxygen field，movement track of particles and the emissions ofnitrogen oxides，researcher found that the temperature of Shixiajiang coal is thehighest, and the Yinni coal is the lowest; the Shixiajiang coal stay in the furnace timeso short,just 5.119s, the design coal stay in it for 5.746s,burning enough; the Xindongcoal contain the most nitrogen, so released much of NO, then, because of lowtemperature in furnace to the Yinni coal, easy to form reducing atmosphere and curbNO, so the NO concentration is minimum; the Yinni coal burning out the fastest, itburning out basiclly in the fold flame Angle area.At last, through comparing with the actual data in the power plant, verified theaccuracy of the simulation results, proved we could choose coal for this power plantby the method of this subject. It is significative to operate optimally by the boiler.