Pyrolysis Process of Waste Tires

Countless tires are scrapped every day. In the past, they were incredibly durable, but now, through pyrolysis technology, they can be converted into oil, carbon black, steel wire, and combustible gases. How exactly did this process work?

Basic Principles of Pyrolysis

Tire pyrolysis is essentially a “thermal decomposition” process. The entire process takes place in an oxygen-free environment, with the core step being heating waste tires to between 300°C and 600°C.

When the temperature reaches a critical point, the molecular chains composed of high-molecular-weight hydrocarbons inside the tire rubber begin to break down and recombine into a mixture of lower molecular weights.

These substances separate in different physical states, ultimately forming three main products:

solid carbon black and steel wire, liquid pyrolysis oil, and gaseous combustible gas.

In this way, the various components of the waste tires are “disassembled” and recycled.

Raw Material Pretreatment

Waste tires typically require pretreatment before entering the pyrolysis reactor to ensure uniform feeding and improve pyrolysis efficiency.

♻️Whole Tire Processing Methods

While some specific processes can directly process small waste tires, most industrial-grade pyrolysis equipment requires pre-crushing of the tires.

♻️Pre-separation of Steel Wires

Using crushing and magnetic separation equipment, most of the steel wires inside the tire bead and carcass are extracted first. This reduces the wear risk on subsequent crushing equipment and facilitates the later classification and recycling of various products.

♻️Crushing and Grinding Process

The tire rubber blocks after steel wire separation are further crushed into fine rubber particles or powder. The finer the particles, the larger the specific surface area, resulting in higher heat transfer efficiency during pyrolysis and a more complete reaction.

Pyrolysis Reaction Process

The pretreated granules are fed into the pyrolysis reactor through a closed feeding system to begin the core pyrolysis reaction.

♻️External heating

The reactor is heated from the outside, primarily using combustible gas generated by the equipment itself; additional fuel is added if necessary.

♻️Pyrolysis reaction

The rubber powder is heated to 400-500 degrees Celsius inside the reactor. Upon heating, the rubber and organic matter inside begin to decompose, slowly transforming from a solid into a gas.

♻️Continuous operation

Modern equipment typically involves simultaneously adding material and discharging slag, while also removing oil and gas. This results in higher efficiency and more stable production.

Collection and Separation of Products

The high-temperature mixed products exported from the reactor need to undergo multiple processes for separation and purification.

♻️Oil-Gas Separation and Condensation

The high-temperature oil and gas exiting the reactor first enters a gas separator or settling tank. Heavy oil is first condensed and collected at the bottom; the remaining light component gas then enters the condensation system. After multi-stage cooling, the light pyrolysis oil becomes liquid and is stored, leaving only the combustible gas.

♻️Solid Product Processing

After pyrolysis, what remains in the reactor is mainly a mixture of carbon black and steel wire. This mixture is discharged and sent to a magnetic separator. The steel wire is extracted, packaged, and recycled, leaving only crude carbon black.

♻️Crude Carbon Black Deep Processing

The freshly produced crude carbon black contains many impurities and does not meet industrial standards. It needs to undergo grinding, modification, granulation, and other processes to improve its purity, density, and stability before it can be sold back to the rubber, plastics, or ink industries.

Energy Recovery and Environmental Control

♻️Gas Recycling

The non-condensable combustible gas produced by pyrolysis, containing methane, hydrogen, etc., can be burned as fuel. After purification, this gas is returned to the combustion chamber to heat the reactor, achieving energy self-sufficiency.

♻️Environmental Control Measures

The entire pyrolysis system operates under a closed negative pressure, preventing any gas from escaping. The small amount of waste gas produced undergoes dust removal and desulfurization before being discharged, meeting standards. Wastewater is also collected and treated centrally, either reused or discharged in compliance with standards, essentially achieving zero emissions.

At Gomine, we have state-of-the-art tire pyrolysis equipment. If you have any tire pyrolysis needs, please feel free to contact us. We will customize a solution tailored to your production volume and budget.