Optimal Recovery of Recycled Carbon From Used Industrial Tires

Since 1993, the Quebec government has implemented scrap tire management programs to reuse, recycle or energetically recover the carbon from tires used in the industrial world. Between 2015 and 2017, the quantity of used tires increased by nearly 20%, from 76,339 tons to 90,142 tons to be processed each year. In addition, tire consumption is expected to remain the same or increase over the next few years. Tires are composed of different layers of materials, a large part of which is carbon-based, and it is therefore possible to speak of  "recyclable" carbon, but it is not necessarily always recycled.

In a context of sustainable development and in a perspective where Canada is trying to limit the landfill of waste as much as possible, it is becoming increasingly important to develop profitable alternatives to take advantage of the recyclable carbon content of residues that could otherwise prove problematic for the environment.

This project aims to take advantage of used tires, starting with industrial tires of the OTF (off the road) type, passing by aircraft tires, and finally road tires, to be valorized by microwave-assisted pyrolysis. The process developed by the partner on an industrial scale will allow the conversion of used tires to generate solid (carbon black), liquid pyrolytic oil) and gaseous (synthesis gas) fractions. While the solid and gas fractions are already well integrated in the company's business plan, the liquid portion, although it can be used as fuel, could benefit from an optimized valorisation.

Thus, within the framework of this project, the pyrolytic oil will be initially treated via a solvent extraction to extract two phases: the refined phase (aromatics free phase), which could be treated with a hydrotreatment process, and the extracted phase (aromatics containing phase). More specifically, this portion of the project will involve support from CRIBIQ, which will focus on the extraction and valorization of the extracted phase to produce rubber processing oil, a product whose price is typically between 1.3 and 2.6 CAD/L. The project will also focus on process optimization and life cycle analysis to quantify the emissions obtained during the different phases of the waste tire valorization life.