Pollutant Emissions during Co-incineration of Landfill Material Refuse-Derived Fuel in a Lab-Scale Municipal Solid Waste Incineration Fluidized Bed Furnace

Landfill material refers to the waste that has been buried in landfill sites for a long time. The combustible components of landfill material can be made into refuse-derived fuel (RDF) for energy utilization. According to previous studies, landfill material refuse-derived fuel (LMRDF) mainly consisted of plastic and rubber with a relatively high calorific value. In this study, the proximate and ultimate analyses of LMRDF and municipal solid waste were compared. The kinetic analyses of LMRDF, RDF, and their mixture with different ratios were also conducted. Furthermore, the pollutant emissions during co-incineration of LMRDF in a lab-scale municipal solid waste incineration (MSWI) fluidized bed furnace were investigated. The effects of the co-incineration ratio, incineration temperature, and water content of LMRDF on pollutant emissions were also observed. The emissions of NOx, SO2, CO, and HCl varied a lot under different experimental conditions, while the contents of heavy metal in the flue gas and fly ash almost remained the same. Additionally, the concentration of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in the flue gas when 30 wt % dried LMRDF was co-incinerated at 850 °C was the lowest, with the value of 7.53 ± 0.89 ng/m3 (0.63 ± 0.26 ng of I-TEQ/m3). It was supposed that the soil attached on the LMRDF enhanced the furnace fluidization level, resulting in better combustion of waste. The good correlation of HCl and PCDD/F concentrations in the flue gas was found. Most importantly, the concentration of PCDD/Fs in the fly ash increased with the co-incineration ratio of LMRDF because more Cu and Cl entered the furnace with the soil impurities. The ratios of PCDFs/PCDDs in all of the flue gas and fly ash are greater than 1, indicating that de novo synthesis might be the dominant way to form PCDD/Fs. In summary, the results revealed that co-incineration of a certain amount of LMRDF in the MSWI fluidized bed furnace would not largely increase the pollutant emissions.