Studies On Pyrolysis And Incineration Of Medical Waste In Rotary Kiln

Medical Waste (MW) is the number one hazardous waste listed in National Catalogue of Hazardous Wastes, which contains large quantity of bacteria and viruses. Improper disposal of MW will cause serious environmental threat.Funded by National Natural Science Foundation Project "Study on Hazardous Waste Incineration Mechanism in Rotary Kiln No 50276055", study on pyrolysis & incineration of MW in rotary kiln was carried out. Based on the investigation of basic features of MW, the micro-scale pyrolysis and incineration mechanism of MW (TGA) and fast pyrolysis characteristic were studied. Experiments on batch feeding and continuous feeding of rotary kiln were carried out, and combustion properties of pyrolysis residues and oil were investigated through TG system. Finally, a new MW pyrolysis & incineration rotary kiln system was put forward and experiments on the demonstration centralized MW disposal system were carried out.Part I, Study on basic features of MW. Based on the review of current situation of MW treatment in both domestic and abroad and various disposal technologies, the MW pyrolysis & incineration through rotary kiln is considered an advanced disposal technology suitable for the situation of China. Through detailed discussion of the definition and classification of MW and referring to many documents and field investigation, summarization was made on the generation feature, toxicity and infectivity of MW in China. Actual compositions, moisture content, heat value, density etc. basic physical properties were obtained through investigations, which provides foundation for the design of MW centralized disposal system.Part II, Micro-scale pyrolysis mechanism studies: Pyrolysis and incineration kinetics of eight typical components of MW were thoroughly studied through thermal gravity (TG) system. The effects of factors such as heating rate, atmosphere etc. on TG property of every component were analyzed. Based on the kinetic characteristics study, an apparent-multistep-one-order MW pyrolysis & incineration model was set up. TGA results demonstrated that the pyrolysis of MW was actually a linear superposition of every components, based on which the MW mixture apparent-multistep-one-order model was proposed and the pyrolysis reaction kinetic simulation of the MW mixture was successfully carried out. Investigation on fast pyrolysis feature of the typical MW components and the effects of final pyrolysis temperature (FGT), quality, size and moisture content on the TG properties of every components were carried out as well as the fast pyrolysis feature of MW mixture.Part III, Experimental investigation on rotary kiln: Investigation on the pyrolysis and gasification of MW in a 1 kg external heating rotary kiln were carried out and the effects of heating mode, material size, moisture content, final pyrolysis/gasification temperature (FPT/FGT) etc. on the distribution and properties of the product were...