Industrial & Engineering Chemistry Research, Vol.43, No.17, 5133-5145, 2004
Pilot-scale pyrolysis of scrap tires in a continuous rotary kiln reactor
The pilot-scale pyrolysis of scrap tires in a continuous rotary kiln reactor was investigated at temperatures between 450 and 650degreesC. As the reactor temperature increased, the char yield remained constant with a mean of 39.8 wt %. The oil yield reached a maximum value of 45.1 wt % at 500 degreesC. The pyrolytic derived oils can be used as liquid fuels because of their high heating value (40-42 MJ/kg), excellent viscosity (1.6-3.7 cS), and reasonable sulfur content (0.97-1.54 wt %). The true-boiling-point distillation test showed that there was a 39.2-42.3 wt % light naphtha fraction in the pyrolytic oil. The volatile aromatics were quantified in the naphtha fraction using gas chromatography-mass spectrometry. The maximum concentrations of benzene, toluene, xylene, styrene, and limonene in the oil were 2.09 wt %, 7.24 wt %, 2.13 wt %, and 5.44 wt %, respectively. The abundant presence of aromatic groups was also confirmed by functional group Fourier transform infrared analysis. The concentration of polycyclic aromatic hydrocarbons such as fluorine, phenanthrene, and anthracene increased with increasing temperature. The pyrolytic char was composed of mesopores with a Brunauer-Emmett-Teller (BET) surface area of about 89.1 m(2)/g. The char after carbon dioxide activation had a high BET surface area of 306 m(2)/g at 51.3% burnoff. The relationship between the surface area and the carbon burnoff was almost linear. Both the original pyrolytic char and the activated char have good potential for use as adsorbents of relatively large molecular species.