Used Tires Of Rotary Kiln Pyrolysis Process In A Pilot Study

As a kind of special solid wastes, waste tyre differs from common MSW. It can't decompose spontaneously and isn't suitable for land-filling because of its large capacity and low density. The treatments of waste tyre can be included as physical methods and chemical methods. As a traditional chemical engineering technology, pyrolysis plays an important role in the waste tyre treatment, which has attracted much attention. This paper aims at the pyrolysis technology of waste tyre, which is based on our pilot scale rotary kiln reactor.The one step reaction model with one reaction order is applied to simulate the pyrolysis dynamics of waster tyre. The results of the simulation are compared with the experimental results, which imply that the model can indicate the characteristics of the waste tyre pyrolysis dynamics. The movement characteristics of waste tyre scraps in the kiln are analyzed with PTM model. The MRT and RTD of waste tyre scraps in the kiln are modeled by the PTM model. The characteristics of heat transfer are studied with one dimension axial model, by which the temperature distribution according to the axial position of the waste tyre scraps and the gas in the kiln was studied. The mechanisms of key heat transfer portions are discussed in this paper. The temperatures of the waste tyre scraps and gas increase along the kiln axis, while the increment ratio decrease along the axis.The characteristics of waste tyre scraps pyrolysis in the kiln are the key studying goal. The influence of temperature on the pyrolysis characteristics is discussed with emphasis with enough residence time. The experiment results imply that the ratio of pyrolysis char decreases with the pyrolysis temperature increasing, the ratio of pyrolysis oil increase till the pyrolysis temperature rising to 550 癈, and then decrease smoothly with the temperature increasing further, while the ratio of pyrolysis gas increase with the temperature increasing.The characteristics of pyrolysis char are analyzed in detail. Comparedwith the merchant carbon, the pyrolysis char is inferior. But it.has more potential application after further processing. The pyrolysis oil is also analyzed and compared with several kinds of crude oils. The results indicate that the pyrolysis oil is competitive in some aspects, such as flash point, vicious, etc. So, the pyrolysis oil has wide uses, it can be used as fuel, chemical raw material, etc. After further refined, it can be competitive with the merchant petroleum. From all of above, the pyrolysis of waste tyre in the kiln is feasible and economical. It can be applied in the near future after further detail investigation.