对冲燃烧锅炉低负荷运行优化数值模拟研究

Numerical Simulation of Low-load Operation Optimization for Opposite Firing Boilers

优化磨煤机组合运行方式可改善锅炉低负荷运行时存在投运燃烧器层截面温度下降、SCR烟气温度偏低、NO_x质量浓度大幅升高等问题,但效果有限。针对上述问题,提出了两种优化方案:提高锅炉运行氧量和采用烟气再循环。数值模拟表明:两种方案均可提高SCR入口烟气温度,但采用烟气再循环可使炉膛出口NO_x质量浓度降低10 mg/m^3以上,且对锅炉效率影响更小。

Optimizing mills-running could improve the problems of temperature decrease in burner layers,low temperature at SCR inlet and high NO_x mass concentration of flue gas when boilers are running at low-load condition,but the effects are limited.Based on the above problem,this paper provides two optimization schemes:improving furnace oxygen content and employing flue gas recirculation.The numerical simulation results indicate that two optimization schemes could increase flue gas temperature at SCR inlet,but the second scheme could reduce NO_x mass concentration more than 10 mg/m^3 while slightly affecting the boiler efficiency.