Study On Salt-Bath Pyrolysis Of Waste Tires

Today, on one hand, the increase of people's living standard and development of other industries are promoted by rubber industry, and on the other hand, waste tire becomes more serious which does great harm to our surroundings. Liquefaction of waste tires by pyrolysis for recovery of fuel oil hydrocarbons can not only eliminate the pollution and this is helpful for environmental protection, but also can gain a lot of valuable materials. The pyrolysis of waste tires meets the requirement of recycle economics.In this paper, pyrolysis of waste tires particles was carried out in molten ZnCl2. Characteristics of conventional and salt-bath pyrolysis were studied systematically. Results showed that the optimal conditions for the reaction was temperature between 520℃and 550℃, and mass ratio between ZnCl2 and plastic was 1:1, waste tire particles was 16 orders, carrier gas flow rate was 80mL/min.Gas and liquid products were analyzed using GC and GC-MS with internal standard method. Methane content which reached 49.25%was high in gas product. The aromatic hydrocarbon and aliphatic hydrocarbon were higher content in liquid product , the content of benzene, toluene, xylene were high in aromatic hydrocarbon of light oil, olefin content reached 70% in aliphatic hydrocarbon of light oil. There was obviously differences in particle size and dispersion of carbon with different pyrolysis temperature in solid phase, coalescence occurred relatively serious and particle size was larger in lower temperature, with the increase of temperature, the pyrolysis was executed thoroughly with more dispersive and smaller particle size.Free radical and carbonium ion reaction mechanisms appeared in salt-bath pyrolysis. After reasonable simplified assumption, a lump-kinetic model was set up including tires, gas, liquid, oil, coke and intermediate product. The analytic and numerical solutions were put forward. The dependability and accuracy of this model were testified after comparison between experiment and calculated valve.Aiming at to gain more benefits, the potential applications of pyrolysis products was discussed here.