Study On Out Heating Pyrolysis Technology Of Municipal Solid Waste

Resource and environment are two major topics in 21th. century, and disposal of municipal solid waste (MSW) is an important task in the two topics. MSW will become a renewable resource with right disposition, otherwise it will pollute environment seriously. The disadvantages of traditional MSW disposal methods such as landfill, composting and incineration are becoming more and more obvious as well as the people's environmental conscious are improved, and the standards of MSW disposal technology are enhanced. The lack of landfill is the great area field it engaged, for composting, it is the little disposal capacity and low efficiency. An obvious problem with MSW incineration is its high capital and operating costs. Difficulties of ash pre-treatment before landfilling and distribution pollutants such as dioxin into the environment also hamper development of MSW incineration.Pyrolysis technology is one of the most important MSW disposal technics with little secondary pollution, quite innocuity and high reusability. Organic components in MSW can be changed into useful fuel by pyrolysis device. Pyrolysis technology is to be payed more attentions by the researchers all of the world.The main objective of this work is to study pyrolysis characteristics of typical components of combustible MSWs and to find out the optimized conditions of MSW pyrolysis process. For this purpose, this study has been processed as the following aspects:Firstly, the principle of pyrolysis used in MSW disposal is studied in depth, as well as the craft and chemical reaction process of it. The present research conditions and the developments of MSW pyrolysis technology at home and abroad are assessedcomprehensively. The advantages of MSW pyrolysis technology are also pointed out. Detail analysis and comparison of foreign typical MSW pyrolysis technology have been given out.The thermal weightlessness characteristics of four typical combustible MSW: wood, paper, fabric and PVC have been studied in a thermogravimetric analysis apparatus. Pyrolysis kinetics has been obtained by using multi-stage single reaction model, and the kinetics characteristics and parameters indifferent stage of thermal conversion process were obtained also. Abundant experiments have been conducted on the pyrolysis of MSW on the outer-heated fixed pyrolyzing furnace, and deeply analyses have been given to the production distribution, the gas characteristics, the pyrolysis gas quality, the characteristics of the pyrolysis solution and residual carbon. The result shows that the pyrolysis temperature is the top-drawer parameter which effects the pyrolysis of the MSW. With temperature increasing, the gaseous yield increase, the yield of pyrolysis solution and char yield decreases accordingly. The main components of pyrolysis gas are carbon monoxide, hydrogen, methane and carbon dioxide. The content of CO, H2 increases in gaseous component while the pyrolysis temperature increasing. The pyrolysis gas calorific value doesn't ascend along with rise of the pyrolysis temperature, and it has a maximum, while residual carbon calorific value has a trend of raise. Pyrolysis solution is most composed of moisture and volatile, while the gross content of the fixed carbon and ash is less than 3%.The paper found a content analyses way of the waste pyrolysis tar: a combined method of planigraphy-gas chromatograph /mass spectroscopy (GC/MS), the tar from the pyrolysis of MSW is divided into several kinds such as acid component, alkaline component, hydrocarbon, and polar components by evaporation, extraction and dissociate. The composition information of the tar can be obtained through the use of GC/MS analysis. It has developed a new technology of outer-heated pyrolysis of MSW and ample experiments have been studied on it. The result shows that combustion technology of biomass provides energy for MSW pyrolysis is an originality measure. The system of the outer-heated pyrolysis run steady and has a high production rate of aerogenesis, which can reach up to 45%; Gas calorific value of the pyrolysis in the process is between 14 and 16MJ, which is triple of the inner-heated pyrolysis. Professional fluent software fairly good simulates the temperature field of the combustion chamber and the pyrolysis chamber, which lays the foundation on the later optimization of the system.The study pay-offs of this work will provide the development and application of the MSW pyrolysis technology with some theory basement and scientific basis.