燃料对生物质炉排炉燃烧特性影响的数值模拟研究

Numerical Simulation of the Effect of Fuel on Combustion Characteristics of Grate Biomass Boiler

对于生物质往复炉排炉实际运行中所面临的燃料波动及适应性问题,以额定蒸发量为130 t/h的往复式水冷炉排炉为模型,用CFD(计算流体力学)技术对锅炉在不同生物质燃料条件下的燃烧过程及污染物排放特性进行了模拟。结果表明,不同入炉燃料的不同成分对其燃烧过程及产生的烟气成分有一定的影响。模板混合燃料中氮元素含量较高导致其燃烧时第一烟道出口截面NOX排放浓度达到了412.9 mg/m^3,设计燃料、黄秆混合燃料及灰秆混合燃料对应NOX排放浓度则分别为:206.3 mg/m^3, 190.5mg/m^3, 262.3 mg/m^3。在采用推荐配风方式时,生物质炉排炉对不同入炉燃料的适应性达到了预期,建议生物质电厂在实际运行中选用氮含量较低的燃料。

Given the fuel fluctuations and adaptability in the operation of reciprocating grate biomass boiler,CFD(computational fluid dynamics) is employed for simulation on the combustion process and pollutant discharge characteristics of boilers with different biomass fuels in a reciprocating grate biomass boiler with its evaporation capacity of 130 t/h. The simulation results show that the combustion process and the flue gas composition in the grate boiler are affected due to different compositions of fuels. The high content of nitrogen in the template mixed fuel causes the NOX emission concentration at the outlet of the first flue to be up to 412.9 mg/m^3. The NOX emission concentrations of the design fuel, yellow stalk mixed fuel and grey stalk mixed fuel are 206.3 mg/m^3, 190.5 mg/m^3 and 262.3 mg/m^3 respectively. The adaptability of the reciprocating grate biomass boiler to different biomass fuels is as expected, and the biomass fuels with low nitrogen content are recommended in the actual operation of biomass power plants.