Pyrolysis of Rubber and Waste Tyres
Waste tyres are engineered composite products containing different rubbers, carbon black, steel, sulphur, zinc, textiles and additives. Pyrolysis can separate and transform these fractions into gas, oil, carbonaceous solids and recovered steel, but product quality determines whether true resource recovery occurs.
- Reviewed
A tyre is not simply a ring of rubber.
It is a sophisticated engineered composite.
Typical constituents can include natural rubber, synthetic rubber, carbon black, steel, textiles, sulphur, zinc compounds, oils and additives.
This composition makes tyres both technically interesting and challenging pyrolysis feedstock.
Thermal decomposition
During pyrolysis, the rubber components thermally decompose.
The principal product families commonly include tyre-pyrolysis oil, non-condensable gas, carbonaceous char and recovered steel.
Steel
Tyres contain structural steel.
This fraction does not undergo pyrolysis.
It can potentially be recovered after thermal treatment.
Its material-recovery value depends on cleanliness, contamination and downstream specification.
Gas
The gas fraction may contain combustible components capable of contributing to process heat.
This can improve steady-state energy balance.
Gas composition also reflects rubber chemistry, temperature and process conditions.
Oil
Tyre-pyrolysis oil is chemically complex.
It may contain aliphatic compounds, aromatic compounds, sulphur-containing species and other components.
It may have fuel potential or chemical-feedstock potential.
Crude oil quality and downstream purification remain important.
Recovered carbonaceous material
The solid carbon fraction contains original reinforcing carbon black, new pyrolytic carbon, mineral matter, zinc, sulphur-containing compounds and other residues.
It should therefore not automatically be called commercial-grade carbon black.
Upgrading may be needed before higher-value use.
Product value
Commercial performance depends heavily on whether the outputs become saleable raw products, upgraded industrial products, fuels or low-value residues.
A process producing large quantities of material with no suitable market may be technically functional but commercially and environmentally weak.
Operating variables
Influential variables include temperature, heating rate, residence time, particle size, reactor configuration and catalysts.
Significant selectivity trade-offs can occur among oil, char and gas depending on these variables.
Sulphur
Tyres contain sulphur because vulcanisation is fundamental to rubber manufacture.
Sulphur can therefore influence gas composition, oil quality, product upgrading and emissions control.
Environmental comparison
Pyrolysis should be compared with real alternative tyre-management routes such as retreading where feasible, material recycling, use in engineered applications, controlled energy recovery and disposal.
The correct route depends on tyre condition and the system boundary.
Governing principle
Tyre pyrolysis creates several potentially useful fractions.
The environmental and commercial conclusion depends not on producing those fractions, but on their quality, recovery, upgrading and actual use.
Selected sources and scope
Sources support the indicated concepts or dated assessments; they do not endorse GCCEI or validate a particular installation. Checked on 18 October 2026.
- R32 · Papuga et al.: Pyrolysis of Tyre Waste in a Fixed-Bed Reactor. 3 December 2023. Laboratory tyre-pyrolysis products and operating-variable effects; not a commercial yield or emissions guarantee.
- R33 · Li et al.: Migration and transformation of sulfur during pyrolysis of waste tires for high-value utilization of poly-generation products. 15 July 2025. Experiment-specific sulfur distribution and transformation among tyre-pyrolysis products; no yield or sulfur-removal percentage transferred.
- R08 · US EPA: Non-Hazardous Materials and Waste Management Hierarchy. Web resource, accessed 18 October 2026. Prevention, reuse, recycling, energy recovery and disposal distinctions.