垃圾热值对焚烧炉烟气再循环运用的影响研究

Research on the Influence of Lower Heat Value on Exhaust Gas Recirculation Technology in Incinerator

垃圾分类和协同处置工业有机固废的推进,使得垃圾热值(LHV)逐步升高,进而影响烟气再循环(EGR)技术在垃圾焚烧炉中的运用效果。本研究通过理论计算、数值模拟和工程试验方法,分析了垃圾LHV对垃圾焚烧炉运用EGR系统的影响。结果表明:垃圾LHV高于7 953 kJ/kg时再循环烟气比例控制在15%~20%效果最佳,可降低炉膛平均温度约50℃,减少炉膛结焦,提高运行稳定性;EGR耦合低空气比燃烧技术能提高锅炉效率,且垃圾LHV越高其提高锅炉效率越明显;同时EGR能有效降低焚烧炉NO_(x)源强,可将锅炉出口NO_(x)控制在100mg/m^(3)(11%O_(2),干基)以下,实现焚烧炉低NO_(x)源强的高效清洁燃烧。

The advancement of waste classification and co-processing of industrial organic solid waste had gradually increased the lower heat value(LHV)of waste,which in turn would affect the application effect of exhaust gas recirculation(EGR)technology in waste incinerators.The influences of waste LHV on the EGR system of waste incinerators through theoretical calculations,numerical simulations and engineering test methods were analyzed.The results showed that when the waste LHV was higher than 7 953 kJ/kg,the best effect was to control the proportion of EGR at 15%~20%,which could reduce the furnace temperature about 50 ℃,reduce the coking of the furnace and improve the operation stability.EGR coupled with low air ratio combustion technology could improve the boiler efficiency,and the improvement effect was more obvious with higher waste LHV.At the same time,EGR could effectively reduce the source strength of NO_x in the incinerator,and the NO_(x) could be controlled below 100 mg/m^(3)(11% O_ (2),dry basis)at the outlet of boiler.To achieve highefficiency and clean combustion with low NO_(x) source strength in the incinerator.