The Characteristics Analysis Of The Gases And Activation Of The Char Of Scrape Tires By Pyrolysis In Rotary Kiln

The degradation of tire, natural rubber(NR) and polybutadine rubber(BR) of different granularity by using thermogravimetric-fourier transform infrared spectrum(TG-FTIR) under atmosphere of nitrogen at three different heating rates(5℃,30℃,100℃/min) is researched in this paper . The characteristic of weight loss of tire or rubber was studied by means of non-isothermal thermogravimetric analysis. The thermal degradation models were calculated by using least squares algorithms and the kinetic parameters were determined. The simulations by the proposed models agreed well with experimental data. The volatile in the process of degradation was analysed by FTIR and the spectrums were compared with each other. It shows that there are two stages in the degradation of tire: the first stage is the degradation of NR and the second stage is the degradation of BR.The scrape tires were pyrolysed under atmosphere of inertia in a pilot-scale rotary kiln designed by Zhejiang University. Pyrolysis experiment was carried out at 500℃, 550℃, 600℃ and 650℃. When the system was steady, pyrolysis gas was collected and analysed by gas chromatography. The experiment shows that tyre pyrolysis gases are composed of CO,CO2,CH4,C2H4,C2H6,C3H8, C4H8, and its unsaturated derivatives. In the experiment temperature of this paper, the pyrolytic gases yield increased with increasing pyrolytic temperature. From the study we realized that volatile matter have different stayed time in the kiln and changed characters under different pyrolytic temperature when the kiln was run at a minus pressure. The yield of CH4 has a maximum level at 500℃,while that of C2H4 are at 550℃. Though the higher temperature will contribute to the second degradation of high molecular hydrocarbon, having less time in the kiln, the high molecular hydrocarbon yield is higher than it at the other temperature, over 10%. At last, we calculate the gross calorific value of the pyrolytic gas. It shows that gas will provide enough energy to the degradation of tire.For the purpose of studying the effect of different activation and pyrogenation conditions on the porosity of carbon produced from waste tyre rubber pyrolysed in the pilot-scale rotary kiln pyrolyzer, a activation furnace was designed in which the tyre carbons was activated. Because steam activation carbon has a narrower and more extensive microporosity than carbon dioxide activation carbon, stream is the only oxidising agent in this paper. Several tyre carbons which have different dimensions was activated in steam in different activation temperatures(800℃,900℃,orl000℃), and we concentrates on the differences in the use of different activation temperation over a wide range of degrees of activation. The activated carbons were investigated for their porosity and surface area using nitrogen gas adsorption. The result shows that total micropore volumes and BET surface areas increased with the degree of activation to 0.499 ml/g and 897.2 m2 /g, respectively, while the development of external surface area was particularly rapid at degrees of activation above 50 wt% burn off. Activation at higher temperatures or longer time will resulted in pores of larger dimensions, although this was only evident in highly activated samples.Adsorption isotherms of were measured on selected activated carbons representing various pore sizedistributions. Isotherm data were analyzed using different methods. BJH method was used to obtain the volume of mesopores and the pore size distribution on the selected samples, while the MP methed was used to obtain the obtain the micropore size distribution. Compared with the conventional activated carbon, the tyre activated carbon have less micropores and more mesopores.