Effect of heating rates on the fate of sulfur during waste tire pyrolysis

The sulfur migration and transformation during waste tire (WT) fast pyrolysis is one of the important influencing factors on the properties of the product. However, WT's thermal history in the previous literature was out of the scope of most actual industrial reactors. To better guide the actual pyrolysis process, the influence of the heating rate on the fate of sulfur in the WT pyrolysis process was investigated by employing a wire mesh reactor. The results showed significantly increasing the heating rate promoted the sulfur migration into volatiles, which indicated WT fast pyrolysis could result in the risk to the environment and the economic value of products. The organic-S was converted to inorganic-S under the effect of ZnO. ·C₄H₆· and ·C₅H₈·, which were the monomers of natural rubber and butadiene rubber respectively, could combine with sulfur radicals to generate thiophene. Severe secondary reactions occurred to convert thiophene to aromatized thiophene during WT slow pyrolysis. These findings could provide insightful guidance for minimizing sulfureous volatile formation and emissions.