Driven by the circular economy and the urgent need to valorize waste, pyrolysis technology has become a key method for treating organic solid waste. Among them, tire waste pyrolysis and oil refining technology has become relatively mature, forming a complete set of equipment and industrial chain. At the same time, plastic waste, as a type of waste with large stock, various categories and urgent treatment needs, is seeing an increasingly pressing demand for its resource utilization. Then, can pyrolysis equipment designed for tires be directly applied cross-border to process plastic waste? The answer is: it is highly feasible in terms of process principles, but critical technical adaptation gaps must be bridged in engineering practice.
At their core, both waste tires (primarily rubber) and most plastics (petroleum-based polymers) are macromolecular organic solid wastes. The core of their resource utilization relies on pyrolysis — a technology that causes macromolecular chain scission through heating under oxygen-free or oxygen-deficient conditions.
Both tire waste and plastic waste follow the basic framework of feeding-pyrolysis-condensation-product collection in standard continuous or batch pyrolysis processes. Raw materials are heated to a specific temperature range (usually below 600℃) in a pyrolysis furnace to undergo pyrolysis reactions, where macromolecules break down and eventually produce an oil-gas mixture. The oil-gas is separated by a condensation system into liquid pyrolysis oil and non-condensable pyrolysis gas. Pyrolysis gas is often recycled for system heating to achieve internal energy circulation, and the final solid residue is what we commonly call pyrolysis char. Consequently, existing tire pyrolysis systems offer a proven technological vessel and framework that can be adapted for plastic waste valorization.
The main products of both tire waste and plastic waste pyrolysis are pyrolysis oil, pyrolysis gas and pyrolysis char. This means that the back-end supporting subsystems such as product collection, storage and gas recycling can be largely shared without fundamental reconstruction.
However, processing capability does not automatically translate into efficient, safe, and compliant operation. Directly applying tire waste pyrolysis equipment to plastic waste pyrolysis may face a series of severe challenges arising from the inherent differences in raw materials.
Low-density, bulky plastic waste (such as films) has completely different physical properties from crushed tire waste. The original feeding systems may fail to convey plastics stably and uniformly, and are prone to the bridging phenomenon. Therefore, the matching of front-end pretreatment systems is of great importance. In addition, batch-type systems have better adaptability to both tire waste and plastic waste than continuous-type ones.
Specific types of plastic waste, such as chlorinated plastics (e.g., PVC), generate highly corrosive gases such as hydrogen chloride during pyrolysis. This imposes significantly higher corrosion resistance demands on system materials of pyrolysis furnaces, pipelines and subsequent flue gas treatment systems compared to tire waste pyrolysis， putting ordinary carbon steel components at risk of rapid degradation.
The flue gas produced by plastic pyrolysis, especially that of mixed or halogen-containing plastics, has more complex components and may contain toxic substances such as dioxin precursors. The original flue gas purification subsystems designed for tire waste pyrolysis may fail to meet more stringent emission standards and must be upgraded and transformed.
Pyrolysis oil produced from plastic waste may differ significantly from that from tire waste in terms of composition, acid value and stability, which to a certain extent affects the subsequent utilization value and storage safety of the pyrolysis oil.
Key parameters such as the optimal pyrolysis temperature, heating rate and residence time for plastics are different from those for tire waste and need to be re-explored and precisely controlled. Otherwise, the oil yield of pyrolysis oil will be affected, coking will be aggravated, or excessive non-condensable gas will be generated, which impairs the system thermal balance and safety.
The composition (possibly containing additives, fillers, etc.) and leaching toxicity of pyrolysis char — the solid product from plastic waste pyrolysis — may differ from those of pyrolysis char from tire waste pyrolysis. It is necessary to re-evaluate whether the final pyrolysis char from each material is classified as general solid waste or hazardous waste, and the disposal methods will be adjusted accordingly based on the product classification.
Targeting the characteristics of plastics, dedicated crushing, sorting and homogenization pretreatment systems must be matched to ensure stable feeding. For continuous pyrolysis systems, the reliability of front-end processing devices is particularly important; batch-type systems are relatively flexible in raw material adaptability.
Prioritize dynamic pyrolysis equipment such as rotary kilns to reduce coking through material tumbling; or install built-in automatic decoking devices to achieve non-stop cleaning and ensure long-term continuous operation.
Corrosion-resistant alloy materials or linings are used in parts in contact with corrosive gases to extend equipment service life.
Flue gas purification systems need to add high-efficiency deacidification, adsorption and dioxin control units to ensure up-to-standard emissions.
Establish a process parameter database adapted to raw materials to realize precision automatic control of temperature, pressure and feeding speed, ensuring stable operation and consistent product quality.
Vary Tech's field operations serve as a compelling validation of this cross-application potential. Its continuously operating tire pyrolysis plant, commissioned in 2020 with an annual capacity of 30,000 tons, has run stably for 5 years, with a total of over 76,000 tons of tire waste processed to date. In response to market changes, the project has successfully achieved compatible processing of plastic waste since August 2025, with 7,200 tons processed so far, realizing flexible conversion and efficient processing of two materials with the same pyrolysis system.
While tire pyrolysis systems provide a solid foundation for processing plastics, successful cross-application necessitates systematic adaptation and intelligent upgrades—not mere repurposing.
For pyrolysis operators, the core question should shift from whether the equipment can be used to how much cost is required for targeted transformation and whether the transformed system can ensure safe, environmentally friendly, economical and efficient operation.
The cross-border application of pyrolysis equipment vividly reflects the trend of technological integration and systematic innovation in the circular economy field. It points out a pragmatic path: through refined and customized re-engineering on mature technology platforms, it is possible to address diverse waste processing challenges in a more intensive and flexible manner, driving the continuous evolution of the resource recycling industry toward a more efficient and intelligent future.
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