Abstract: 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 NOx in the incinerator， and the NOx could be controlled below 100 mg/m3 （11% O2， dry basis） at the outlet of boiler. To achieve high-efficiency and clean combustion with low NOx source strength in the incinerator.

Key words: exhaust gas recirculation, lower heat value of waste , NOx, boiler efficiency