用数值模拟方法研究含硫颗粒物生成过程

为了研究不同燃烧条件对燃煤中含硫颗粒物生成的影响,利用数值分析方法模拟炉膛煤燃烧。通过改变燃烧环境温度、进口氧气所占总气体摩尔比,分析得到的碳烟(soot)颗粒、SO2和CO2等主要物质浓度场。模拟结果能够很好地反映炉膛内各物质生成趋势和历程。生成的碳烟颗粒中富集煤中一部分硫元素,燃烧后期未被氧化的碳烟颗粒是燃煤烟气含硫颗粒物的一个重要来源。进口O2摩尔比从0.1~0.5时碳烟颗粒迅速被氧化,出口处产生含硫碳烟颗粒物减少。在1 200~1 600 K范围内,温度增高不利于碳烟颗粒的生成,来源于碳烟颗粒的含硫颗粒物也就逐渐减少。

Investigation of sulfur-containing particles generation by numerical simulation

Numerical simulation was used to investigate the influences of different combustion conditions on the generation of sulfur-containing particles in the process of coal combustion.The concentration fields of soot particles, SO2, CO2, and other substances were obtained by changing the combustion temperatures and oxygen mole fractions, on which the analyses were based.The results of simulation can display the generation trend of main productions and processes of reactions in the furnace accurately.The results suggest that the generated soot particles enrich a portion of the sulfur element from coal.On the other hand, soot particles that are not oxidized after coal combustion are an important source of sulfur-containing particles.When the molar fraction of O2 changes from 0.1 to 0.5, generated soot particles are oxidized rapidly.Thus, the amount of sulfur-containing soot particles decreases gradually at the outlet.In addition, it is difficult for the generation of soot particles when the temperature increases from 1 200 K to 1 600 K, so the number of sulfur-containing particles from soot particles decreases gradually.