Waste tires based biorefinery for biofuels and value-added materials production

Waste tires are a distinct type of waste material that is produced in large quantities. These tires present a significant environmental challenge due to their high toxicity and flammability, as well as their persistence and the difficulty of storing or processing them. Every year, approximately 1.4 billion waste tires are produced, and they typically end up either in landfills or being incinerated, exacerbating these environmental problems. However, waste tires are also a promising source of energy and energetic materials, thanks to their low moisture content, heterogeneous nature, and high heating value. Waste tires are comprised of various materials, including carbon black, fabric, filler, antioxidants, natural rubber, and steel wire, all in different compositions. This study provides an in-depth analysis of the various methods for converting waste tires into biofuels, green chemicals, and innovative materials for energy and environmental applications. The study specifically includes a bibliometric analysis to examine the current research trends, identify knowledge gaps, and explore prospects for waste tire biorefinery. Additionally, a comparative assessment of various traditional strategies for managing waste tires is discussed. The study proposes a new integrated waste tire biorefinery that incorporates multiple methods for the valorization of waste tires, including alternative pathways for integrating thermochemical and biological processes. Bibliometric analysis shows that the frequently used keywords in waste tire-related research include pyrolysis, crumb rubber, recycling, combustion, and activated carbon.