Study on pyrolysis of waste tires and condensation characteristics of products in a pilot scale screw-propelled reactor

Abstract

The pyrolysis of waste tires not only can recycle waste materials and solve environmental problems but also can produce fuel to replace fossil fuels, which has good application prospects. The screw-propelled reactor has good pyrolysis characteristics, but there is little research on pyrolysis experiments at the pilot scale. In addition, by separating the lighter and heavier oils through different condensation temperatures, the transportation safety of heavier oil can be improved, but there is limited research in this area. In this study, a pilot-scale screw-propelled reactor was used to study the characteristics of pyrolysis of waste tires from trucks (WT1) and passenger cars (WT2), and the differences in the properties of the two types of oils were investigated by separating the lighter and heavier oils at different condensation temperatures. The results showed that at four pyrolysis temperatures, the solid yield of WT2 was higher than that of WT1, and the liquid and gas yields were lower than those of WT1. The flash point of heavier oil was generally higher than that of lighter oil. With the increase of pyrolysis temperature, the flash points of the four oils decreased with increasing temperature. Aromatic compounds were the most abundant components in all pyrolysis oils, with proportions in the oil products almost exceeding 40%. H2 and CH4 were the most important components in the gaseous products, with volume fractions exceeding 20%. The proportions of C3H6, C3H8, and C4H8 in the pyrolysis gas of the two types of tires were similar, all between 6% and 8%. Sulfur mainly existed in the form of H2S in the pyrolysis gas, with a concentration range of 840 ∼ 941 μL/g.