Recycling of Solid Products of Municipal Waste Pyrolysis with Production of Energy Fuel

Abstract

The purpose of the study was development of a technology for the extraction of a carbon-rich concentrate suitable for use as an energy fuel from solid products of municipal waste pyrolysis (SPMWP). To do this, the effect of reagents and different flotation conditions on the yield and quality of the carbon-rich concentrate was investigated. The results are presented of the experimental study into the features of the SPMWP flotation process. A relationship has been established between the SPMWP fraction size, the yield of carbon-rich concentrate, and its quality. The fact has been demonstrated that SPMWP flotation characteristics can be improved by ultrasonic dispersion of flotation agents in water and production of concentrates containing, depending on the size distribution of SPMWP particles, from 60 to 67% of combustible matter. Thermogravimetry and differential scanning calorimetry methods have revealed that the combustible matter of the concentrate consists of 65% carbon and 35% volatile carbon-containing compounds. According to the results of X-ray phase analysis, the main water-soluble salts of SPMWP are chlorides of potassium, sodium, and calcium sulfate. As to its heating value (q = 18.4 MJ/kg), the obtained combined concentrate is comparable to coal and can be considered as a renewable energy source since, according to forecasts, the annual increase in the amount of municipal solid wastes (MSWs) will be from 1 to 7%. A schematic diagram of material flows for processing 100 t of SPMWP has been constructed on the basis on the results of performed studies. An additional economic effect can be obtained by using hydroseparation at the stage of municipal waste sorting to separate crushed glass, as a result of which large SPMWP particles may be sent to flotation after grinding.