炉排炉内生活垃圾解耦燃烧NO_(x)排放特性

NO_(x) Emission Characteristics During Decoupling Combustion of Municipal Solid Waste in a Grate Furnace

随着垃圾焚烧烟气排放标准的提高与国补退坡,垃圾焚烧行业亟待高效洁净的新技术。本文以解耦燃烧原理作为技术支撑,在300 t/d垃圾焚烧炉上通过循环再热烟气构建干燥热解区,抑制NO_(x)生成。结果表明,循环再热烟气(270℃)注入焚烧炉的底部炉排第一单元和第二单元效果较好,NO_(x)排放浓度可控制在200 mg/m^(3)(标准工况)以下;随着再热烟气量的增加,NO_(x)降低幅度增大,当再热烟气循环比超过6.22%后,对焚烧工况产生不利影响。相比传统燃烧(TC)和烟气再循环(FGR)工艺,解耦燃烧(DC)能更好地抑制NO_(x)生成,NO_(x)生成量降低43.1%。解耦燃烧试验未对灰渣的烧失率有明显的影响,烟气中O_(2)含量下降至TC的2/3。解耦燃烧投用,吨垃圾运行成本比TC节约5元,为垃圾焚烧运行调控和节能改造提供参考。

As the stringent flue gas emissions limit and the withdrawal of state subsidies,the waste incineration industry is in urgent need of efficient and clean new technologies.In this paper,based on the principle of decoupling combustion(DC),a drying/pyrolysis zone was constructed by circulating reheated flue gas in a 300 t/d waste incinerator,in order to reduce NO_(x) formation.The results showed that the effect of circulating reheated flue gas(270℃)injected into the first and second parts of fire grate of the incinerator is better,and the NO_(x) concentration in the flue gas can be controlled below 200 mg/m^(3)(standard condition);With the increasing of the amount of reheated flue gas,the reduction of NO_(x) formation decreased.It would adversely affect the incineration conditions if ratio of circulating flue gas to total flue gas exceeded 6.22%.Compared with traditional combustion(TC)and flue gas recirculation(FGR)technologies,the decoupling combustion(DC)could better suppress NO_(x) generation,and NO_(x) formation was reduced by 43.1%.The DC had no significant effect on the heat loss rate(or residual carbon amount)of bottom ash,and the O_(2) content in the flue gas dropped to 2/3 of TC.The operating cost of DC for one ton waste was found to be 5 yuan less than that of TC,which is of great significance for the regulation of waste incineration operation and energy-saving renovation.