Behavior of Sulfur during the Pyrolysis of Tires

Abstract

The mechanisms of transfer of sulfur to the volatile phase and char phase during the pyrolysis of tires have been investigated by complementing the available literature data with TGA experiments. For isothermal experiments, the global selectivity expression could be simplified into an intrinsic form of sulfur loss selectivity, which is solely a function of temperature. Two other phenomena have been found to influence the intrinsic sulfur loss selectivity: solid matrix desulfurization and metals sulfidation. In the case where tires would contain no metals and pyrolysis was performed at a temperature of 400°C or higher, decomposition kinetics is limiting and the intrinsic sulfur loss selectivity would converge to the value of 1. Below 350 °C, mass transfer limitation will promote solid matrix desulfurization, producing sulfur loss selectivity greater than 1. Over 350 °C, if zinc and/or steel are present in tires, sulfidation will cluster sulfur in the solid phase and sulfur loss selectivity will become lower than 1. A developed form of sulfur loss selectivity could be obtained to account for these phenomena.

Experimental Study on Spent FCC Catalysts for the Catalytic Cracking Process of Waste Tires

“…The sulfur content in tires is 1-2% [27]. Several studies have focused on the migration and transformation of sulfur elements during the pyrolysis process [28][29][30]. From the above experimental data analysis, it can be seen that the sulfur content in pyrolysis gas was negligible.…”

Valorisation of Waste Tyre via Pyrolysis: Advances and Perspectives

“…To date, very few studies have accounted for the transformation behavior of Zn during waste tyre pyrolysis. Zn presents in the tyre as zinc oxide (ZnO) or zinc stearate (C 36 H 70 O 4 Zn) as a plasticizer to lubricate the vulcanisation 214 and ZnS or charbound S. A temperature above 700 °C leads to the release of Zn from ZnO, 215 while ZnS transforms into Zn(v) and S at the same temperature. 216 The transformation behaviors of ZnO and ZnS are shown in Figure 28, as summarised in the literature.…”

Study on the transformation of organic sulfur in cationic exchange resins in a ternary Li2CO3–Na2CO3–K2CO3 molten salt system

“…When zinc and/or iron were present in tires, sulfur in the form of zinc sulfide and iron sulfide was retained in the solid phase during the pyrolysis of tires. [33][34][35][36] Zhao et al 37 studied the transformation of pyrite in various associations during coal pyrolysis. The results indicated that the Fe-S phase in the pyrolysis products of coal was mainly represented as FeS x .…”