Study On The Transfer Characteristics Of Bromine In Pyrolysis And Incineration Of Typical Components Of Medical Waste

The product of medical waste(MW) is on the rise in recent years, and emission of halogenated hydrogen during thermal treatment of MW has attracted the attention of environment protecting department. The studies of gas pollutant during combustion of medical waste were limited in the range of conventional gas pollutant. Br, although not nearly as ubiquitous as Cl in combustion systems, undergoes a similar set of reactions as Cl. During the pyrolysis and incineration of medical waste containing Br, HBr which cause corrosion of apparatus and toxic pollutant PBDD/Fs will be produced.The studies of some basic problems including formation mechanism, influencing factor and emission regular of HBr in thermal treatment of medical waste is an exploratory work, which provide basic theories and experimental results to the control technology of brominate pollutant. The study includes three parts.Part 1. Based on the discussions of the definition, classification and generation feature of medical waste, review various disposal technologies in both domestic and abroad. The pyrolysis & incineration of MW is considered as an advanced disposal technology suitable for the situation in China. Summarization was made on the research of pyrolysis & incineration characteristics of MW and transfer characteristics of Br in waste during thermal treatment. Several approaches to measure the concentration of Br ion are introduced. Ion chromatography was chosen in this work after compare to other approaches.Part 2. Pyrolysis and incineration process of typical components of medical waste was studied using a fixed bed tubular reactor. On-line gas analyzers measured the content, yield, heat value and percentage of gas produced. The effect of temperature on the gas yield was analyzed. The results indicated that material characteristics, temperature and atmosphere condition have great effects upon yield process and percentage of gas produced.Part 3. Bromine transfer characteristics in the pyrolysis & incineration of typical components of medical waste were studied using a fixed bed tubular reactor. Cotton and polypropylene using as typical components of medical waste, with the addition of inorganic bromine, were the material of the experiments. The emission of HBr, and quantities of bromine in residue and tube were measured. Special attention was given to the effect of temperature on the emission and distribution of bromine, as well as the effect of different material, atmosphere and reaction time. Results show that temperature is an important effect on transfer of bromine. The conversion of HBr from inorganic bromine is relatively low, whereas a large amount of bromine transfers to the surface of tube in high temperature.