电站燃煤锅炉采用空气分级燃烧数值模拟的研究

Study on Numerical Simulation of Staged-air Combustion for Boilers in Power Plants

采用fluen t数值模拟软件,对某电厂400 t/h四角切圆锅炉的炉内湍流流动、传热、燃烧和NOx的生成进行总体的数值模拟。研究了一、二、三次风率的变化对锅炉NOx生成量及炉内燃烧效果的影响。对此煤粉锅炉,采用空气分级燃烧方式有利于降低NOx的生成量,三次风率为22.2%左右时NOx生成量最小,且其他热损失也小,需要配合锅炉尾部受热面的改造,以降低锅炉排烟热损失。

Turbulent flow, heat transfer, combustion and NO~ formation for a 400 t/h tangentially fired boiler are numerically simulated using fluent numerical simulation software. The influence of primary, secondary and tertiary air ratio changing on NO~ producing quantity and combustion effect in boiler have been studied. To this pulverized coal-fire boiler, staged-air combustion style does good to reduce NO~ producing quantity. NO~ producing quantity and other heat losses will be minimized when tertiary air ratio reaches 22.2%. Exhaust gas heat loss could be reduced by retrofit on tail-heating surface.