Study On Co-pyrolysis Characteristics Of Domestic Waste Mixed With High Sulfur Industrial Solid Waste

On the basis of blending fuel types and composition,co-pyrolysis technology regulates the pyrolysis reaction process and reaction products through collaborative technology,so as to obtain a better heat treatment mode with economic and environmental benefits.In this paper,domestic waste and high sulfur industrial solid waste are used as raw materials.Through a series of mechanistic experiments of co-pyrolysis,the effects of different mixing ratio and pyrolysis temperature on co-pyrolysis products and pollutants are explored,and the characteristics of coke inhibiting low-temperature resynthesis of dioxin are further studied,it provides theoretical support for the engineering popularization and application of domestic waste mixed with industrial solid waste pyrolysis technology.After the classification of domestic waste,the proportion of kitchen waste decreased significantly and the proportion of combustible components increased.The dry basis calorific value of domestic waste reached 17.03 MJ/kg.At the same time,due to the high carbon content,the dry basis calorific value of high sulfur industrial solid waste reaches 37.48 MJ/kg,which has a good co-pyrolysis potential with domestic waste.The thermogravimetric experiments of domestic waste and high sulfur industrial solid waste show that the co-pyrolysis process of domestic waste and high sulfur industrial solid waste is conducive to the occurrence of pyrolysis reaction and the formation of light molecular weight components;With the increase of the mixing ratio of industrial solid waste,organic co-pyrolysis produces more small molecular olefins and cycloolefins,while small organic molecules form aromatic compounds through polymerization,so as to improve the yield of pyrolysis oil;The solid residue after co-pyrolysis is 30～40%,which is mainly composed of carbon black and non decomposable bottom slag.The co-pyrolysis of domestic waste and high sulfur industrial solid waste was carried out in a small vertical pyrolysis furnace to study the emission of heavy metals,dioxins and other pollutants.The results show that co-pyrolysis can effectively reduce the contents of Cr,Zn and Cu in coke;The formation concentration of dioxin in the co-pyrolysis flue gas of domestic waste increased from 5.68 ng/Nm~3 to 9.5 ng/Nm~3,while the toxicity equivalent of dioxin decreased from 2.20 ng I-TEQ/Nm~3 to 1.65ng I-TEQ/Nm~3.Therefore,domestic waste co-pyrolysis can effectively reduce the emission of heavy metals and dioxins in flue gas.In order to explore the characteristics of dioxin re synthesis during the co-pyrolysis of domestic waste and high sulfur industrial solid waste,the low-temperature re synthesis experiment of pyrolytic coke was carried out on a tubular furnace test-bed.The results show that the carbon oxidation level of coke produced by domestic waste pyrolysis alone is high,while the coke produced by co-pyrolysis is mainly elemental carbon,and the sulfur content reaches 2.88%,which is helpful to inhibit the formation of dioxin;At the same time,the content of heavy metals such as copper and iron in coke decreased after co-pyrolysis.Therefore,after coke is heated at low temperature,the mass concentration of PCDD/Fs decreases from 6.63 ng/Nm~3 to 2.11 ng/Nm~3.It can be seen that co-pyrolysis coke has low dioxin re synthesis ability,and co-pyrolysis can effectively reduce dioxin emission.In conclusion,the co-pyrolysis of classified domestic waste and high sulfur industrial solid waste helps to improve the yield of pyrolysis oil and reduce the generation and emission level of heavy metals,dioxins and other pollutants in flue gas.The research results can provide theoretical support for the popularization and application of co-pyrolysis technology.