Characterization of oils, gases, and char in relation to the pyrolysis of different brands of scrap automotive tires

Different types and brands of used automotive tires from several countries throughout the world have been pyrolyzed in a fixed-bed reactor under identical conditions. The aim of the experiments was to determine the influence of tire origin on the yield and composition of the products of pyrolysis. The yields of char, oil, anal gas were very similar for the seven tires investigated under the process conditions of pyrolysis operating in this work. The gas composition showed noticeable variations between the tire types pyrolyzed, with each of the main pyrolysis gases of carbon dioxide, carbon monoxide, hydrogen, methane, and other hydrocarbon gases showing different compositions depending on the origin of the tire. The oil derived from the pyrolysis of the tires showed very similar broad compositional properties as measured by infrared spectrometry and size-exclusion chromatography. However, detailed analysis of the oils showed variations in the concentration of certain aromatic compounds depending on the tire type and origin. In addition, experiments were conducted with an equal mixture of all seven tires, and the results of both yield and composition showed that the resultant products reflected the mixture of the individual tire yields and compositions.