Pyrolytic Characteristics Of The Pilot Study

The disposal of waste tires is an increasing environmental problem. In China, the main routes for disposal have centered on open dumping and landfill which have proved to not to attain the request that can keep on the development. By incineration, the thermal value of tires is used, but the incineration is harmful for environment. On the other hand, as a special chemistry technics, pyrolysis not only can recover the energy but also can recover the outcome of the high and additional value. So, pyrolysis developped the important function in processing waste tires.First, the pyrolysis basic characteristics of waste tyre in N₂ atmosphere were investigated using thermogravimetric analysis. It was found that there was an obvious pyrolysis area. More than 60% components already had been decomposed when the temperature attained 500℃. But the pyrolysis rate start to lower when the temperature was higher to 500℃. In addition, the heating rate can change the pyrolysis process and affect the pyrolysis char, oil and gas. But the effect on the ratio of the pyrolysis char, oil and gas was very tiny.Secondly, the characteristics of waste tyre scraps pyrolysis in the vapor atmosphere were the key studying goal. The effect of pyrolysis temperature and the heating rate on the yield and characteristics were researched.The pyrolysis temperature was the vital factor in the pyrolysis of waste tyre and the pyrolysis pressure was inessential. The waste tyre started to decompose when the tempertature was higher to 200℃. The pyrolysis was aboil when the temperature was 500℃⁶50℃. So, this was the main stage in which the pyrolysis went along.With the pyrolysis temperature increasing, the ratio of pyrolysis char decreased till the pyrolysis temperature rising to 500℃, and then keeped stable with the temperature increasing further, while the ratio and production rate of the pyrolysis gas increase with the pyrolysis temperature increasing.The heating rate affected the ratio of the pyrolysis gas and residence time in the tester. In the same pyrolysis temperature, the ratio of the pyrolysis gas decreased as the heating rate increased. The lower temperature can prolong the residence time, andit was advantageous to make the pyrolysis process more thoroughly.The characteristics of pyrolysis char were analyzed in detail. Pyrolysis char is a granular carbonaceous material and there are many pores in the interior. The carbon element content was up to 70% or so and the porosity (mercury-displacing method) was up to 60% or so. When the pyrolysis temperature was reached 55O°C, the porosity was the highest, but continuing heightened the temperature, the porosity decreased. The distribution of pore size was similar to all the conditions studied. The pyrolysis char mainly was composed of mesopores and few micropores have been found. Compared with the merchant carbon, the pyrolysis is inferior. But it has more potential application after futher processing.From all of above, the pyrolysis of waste type in vapor atmosphere is feasible. It can be applied in the near future after detail investigation.