煤粉锅炉掺烧煤化工废气的数值模拟研究

Numerical Simulation on Co-firing Coal Chemical Waste Gas in Pulverized Coal Boiler

煤制气工业会产生大量难处理的酸性废气,对其进行低成本资源化利用具有重要意义。采用数值模拟方法研究了煤制气酸性废气入炉掺烧对煤粉锅炉的影响,分析了不同工况下炉内温度场与燃烧产物的分布规律。结果表明,酸性废气入炉掺烧使炉膛火焰上移,炉膛出口烟温增加,从燃烧器上部掺入废气火焰上移最明显;废气中绝大部分硫化物被快速氧化为SO2,使炉内SO2浓度增加,SO2向SO3的转化率较纯煤燃烧也有所增加;此外,炉内及水冷壁附近基本上不存在H2S气体。燃烧产物在炉内的分布与废气掺入的位置有关联。综合计算结果,在锅炉进行废气掺烧改造时,从燃烧器中部送入废气较为合理。

Coal-to-gas industry produces a lot of acid waste gas which is difficult to be treated. It is of great significance to low-cost resource utilization of waste gas. Numerical simulation method was used to study the mixed combustion of coal chemical waste gas in pulverized coal boiler, the distribution of temperature field and combustion products in furnaces under different working conditions was analyzed. The simulation results show that, acidic waste gas causes the flame in the furnace to move up, and the temperature of the flue gas at the exit of the furnace increases, the flame is most obviously moved when the exhaust gas is added from the upper part of the burner. Most of the sulfide in the waste gas is rapidly oxidized to SO2, which increases the SO2 concentration in the furnace, and the conversion rate of SO2 to SO3 is also increased compared with the combustion of coal. In addition, there is basically no H2 S gas in the furnace and the water wall. The distribution of combustion products in the furnace is related to the location at which the exhaust gas is added. According to the results of numerical simulation, it is reasonable to send waste gas from the middle of burner when the boiler is reformed.