Experimental Research On Thermochemical Disposal Of Municipal Solid Waste

With the improvement of the awareness of protecting environment, the callingon reduce-reuse-recycle (3R) disposal of municipal solid waste (MSW) is becomingstronger. Thermochemical conversion as an effective technology of3R disposal hasbeen a focus that attracts more attention on the MSW treatment. However the basicreserve on thermochemical disposal of MSW still has many limits in domestic.The theoretical analysis and experiment were launched to rsearchthermochemical disposal of MSW. The equilibrium calculation during combustionand gasification was conducted to analyze the effects of moisture content on urbansludge combustion and gasification. Pyrolysis characteristics of scrap tires and urbansludge were researched through thermogravimetric-infrared analysis, and the kineticparameters were calculated using integral method. The pyrolysis experiments of scraptires and urban sludge were conducted in an external-heat fixed bed to investigate theproduct features under different final temperatures. At last, the experimental researchon scrap tires pyrolysis for fuel oil was conducted.Through the research on effects of moisture content on urban sludge combustionand gasification, it is concluded that with the increase of moisture content, thetemperature of incinerator reduced, the calorific value of gasification gas decreasedas the combustible components in the gas lowered, air coefficient increased,gasification efficiency and thermal efficiency reduced. The results ofthermogravimetric-infrared analysis showed that main pyrolysis range of scrap tireswas300℃-500℃, during which the pyrolysis reaction series was1. The pyrolysis ofurban sludge was sectional whose main stage is250℃-500℃, during which thepyrolysis reaction series was2.5-3, and the pyrolysis reaction series was2-3during700℃-850℃. Evolution of gas precipitation was similar under different heating rates.The experimental results of pyrolysis of scrap tires and urban sludge in the fixedbed showed that the main pyrolysis gas compositions of the scrap tires were CH4, H2and CnHm, and of sludge were CO2, CH4and H2. The calorific value of scrap tirespyrolysis gas was high, while the calorific value of sludge pyrolysis gas was lower.The main components of waste tires pyrolysis carbon was fixed carbon, and of sludgepyrolysis carbon was ash component. The production rate of waste tires pyrolysisliquid decreased with the rise of the pyrolysis terminal temperature, the value ofwhich was33%-51%. The production rate of sludge pyrolysis liquid was29%-31%,which was slightly affected by the terminal temperature. The optimal temperature of scrap tires pyrolysis for fuel oil was450℃, under which the oil production rate was40.1%. The effective components of the pyrolysis oil were limonene, ethanol, phenoland various olefins. Preliminary pilot test was carried out in a self-heated fixed bed.It is found that the self-heated pyrolysis system can run steady, but the oil productionrate was low.