More than 1.5 billion scrap tires are generated each year globally. They have stable composition and few impurities, and are mainly composed of natural rubber, synthetic rubber, carbon black, and steel wire. They are essentially recyclable resources in the wrong place. For decades, most scrap tires have either been used as fuel and incinerated in cement kilns, or crushed into low-value-added rubber powder. Although these methods keep tires out of landfills, they do not truly recover their material value—in many cases, they merely turn waste into emissions rather than into new resources.

The proposal of the tire circular economy is essentially a redefinition of this value chain: no longer treating tires as “waste to be disposed of,” but, through scrap tire solutions, as “raw materials to be deconstructed.” In this transformation, pyrolysis technology has become a key technological pivot.

I. Chemical Recycling Pyrolysis That Re-“Disassembles” the Polymer Chain

Pyrolysis technology uses the thermal instability of organic matter to convert large-molecule organic matter into gaseous, liquid, and solid components with relatively lower molecular weights under oxygen-deficient and high-temperature conditions. Unlike mechanical recycling, which can only change the physical form of rubber, chemical recycling can achieve molecular-level regeneration of rubber materials and is regarded by the industry as the ultimate technical pathway for scrap tire recycling. Current mainstream methods for chemical recycling of rubber include pyrolysis, catalytic pyrolysis, supercritical fluid depolymerization, microwave pyrolysis, and enzymatic depolymerization, among which tire pyrolysis is currently the most mature chemical recycling method.

After pyrolysis treatment, scrap tires can be fully converted into products with relatively high added value: recycled oil, pyrolysis carbon black, steel wire, and combustible gas. Among them, the combustible gas, after purification, is directly reused as a relatively clean fuel for pyrolysis heat supply, while the remaining products can be sold directly.

II. How Pyrolysis Changes the Tire Circular Economy

First, from “downcycling” to “closed-loop return.” The endpoint of traditional recycling is usually low-value rubber powder or fuel, whereas the goal of pyrolysis is to return products to the manufacturing end. When the quality of pyrolysis carbon black reaches tire manufacturing standards, scrap tires are no longer the endpoint of the industrial chain but become the raw material starting point for new tires—this is exactly the core of the “tire-to-tire” closed loop.

Second, from “partial recycling” to “systematic resource utilization.” The complete tire circular chain is summarized as “production—use—retreading—recycled use—end-of-life—pyrolysis,” which is regarded as the most ideal way to “fully utilize every last bit” of rubber resources and one of the best approaches for the harmless and resource-oriented treatment of scrap tires; the industry calls it the “ultimate means” of tire life. The reason pyrolysis can assume this role is that it simultaneously addresses the three goals of reduction, harmless treatment, and resource utilization.

Third, from “environmental burden” to “measurable value.” By converting scrap tires almost 100% into resources, pyrolysis generates significant economic benefits. This is reflected not only in product sales revenue but also in the cost advantage brought by energy self-sufficiency—non-condensable combustible gas, after purification, is used as fuel for the heating device, reducing external fuel consumption and flue gas emissions.

III. Niutech: An Example of Turning a “Technical Route” into an “Industrial Paradigm”

Niutech has focused on pyrolysis technology for nearly 40 years. As a standard setter and technology leader in China’s pyrolysis technology field, it has independently developed a complete continuous tire pyrolysis system and is one of the few equipment manufacturing enterprises in the industry to achieve long-term, stable, industrial continuous operation of pyrolysis equipment under the premise of safety and environmental protection.

Industrialization implementation is the ultimate standard for testing technology. Niutech’s typical application case in China is the Shandong 100,000 tons/year scrap tires comprehensive utilization project, which has truly achieved long-term safe, stable, and industrial continuous operation; internationally, it has been exported to Germany, the United Kingdom, South Korea, Denmark, Brazil, Hungary, Turkey, Estonia, Iraq, India, and many other countries and regions.