| Pyrolysis of Solid waste is one of the most significant thermal conversion technologies for producing clean fuels (gas, oils or char) and speciality chemicals (aromatics, activated-carbon or carbonblack). There were three primary objectives of this work. The first was to selectively study the possibility of rotary kiln as a pyrolysis reactor. The second objective was to study the mechanisms of pyrolysis of solid waste both in micro-scale batch (TG-DTG) and lab-scale batch system. Finally, the end part of this work was conceived as the preliminary experimental evaluation of the technical feasibility of converting wastes into oils, carbonblack (or activated carbon) in a pilot-scale continuous rotary kiln process.(1) Rector Phenomena studies: The transport process as well as heat transfer of solid materials was intensively studied. Firstly, the bed regimes of solids in rotary kiln were discussed and the rolling regime is preferred in the engineering practice. The experiments on the influences of operational variables on the axial transport of both heterogeneous MSW (municipal solid waste) were conducted in a continuous rotary kiln cold-simulator. On basis of above experiments, a novel particulate trajectory model (PTM) was developed to simulate axial transport and dispersion, namely detailed residence time distribution, of MSW in a rotary kiln, of which the segregation characteristics of MSW is incorporated into PTM. Reasonable agreement is successfully obtained between simulated results and experimental ones. Second, the paths or mechanisms of heat transfer in rotary kiln were analyzed. Especially, the influence of rotating on heat transfer coefficients was originally discussed. On this basis, a one-dimensional axial heat transfer model for rotary kiln was presented. The model predictions show good agreements with the experimental data in literature. In a conclusion, rotary kiln is a slow-heating process unit, but convenient to the feed of solids without any size limit and favorable to the mixing of carbonous products due to its rotation. Therefore, rotary kiln can be used as either as a pyrolyser of scrap tyre whose reaction are rarely dependent of heating-rate, or as a pyrolyser of mixed biomass-borne wastes whose sizes are too diversified to feed easily.(2) Pyrolysis mechanism studies: The mechanisms of pyrolysis of solid waste both in micro-scale and lab-scale batch systems were thoroughly studied. Waste tyres were selected as the main class of solid wastes to be studied, while biomass-borne mixed wastes as the comparative one. Micro-scale TG-DTG results showed that pyrolysis kinetic of waste tyre can be regarded as the linear accumulative total of each elastomers (NR, BR or SBR) as well as their process oils, among which the scope ofreaction is from 250℃ to 520℃. It is noted that the kinetic are rarely dependent to the variation of heating rate. Moreover, the lab-scale pyrolysis characteristics of waste tyres, biomass or mixed wastes were conducted in a batch kiln. The influences of final temperature and rotational speed on both yields and properties of pyrolytic products were discussed. At last, the '3R+2T' criteria (3R: Pyrolysis Reaction, Secondary Cracking Reaction of vapors and Char Gasifying Reaction, 2T: Temperature and Time of residence) was firstly proposed in order to determine the optimal pyrolysis conditions required to maximise the recovery of pyrolytic products yields.(3) Pilot-scale evaluation studies: the Process Development Unit (PDU) of 20kg/h rotary kiln pyrolyser of scrap tyres was finished on basis of studies of aforementioned two parts. The subsequent evaluating experiments were conducted in a range of 450℃ to 650℃ The yield of char is about 38.8-43.9%, while those of oils about 42.7-45.1%. The pyrolysis liquids can be used as a fuel oils due to its high heating value (40-42 MJ/kg) and excellent performance of viscousity (1.6-3.7cS). Furthermore, through the proper cutting with respect to required distilling temperatures, the liquid...
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