Recent advances of energetic valorization technologies for waste tires: A systematic review of thermochemical and integrated processes, challenges, and future directions

Increasing amounts of waste tires have constantly placed a huge burden on the environment, highlighting the urgency of waste tires valorization. This review aims to provide an overview of recent advances in energetic valorization technologies including incineration, pyrolysis, and gasification. The underlying correlations between critical factors and products are concluded based on experimental and theoretical studies. Co-valorization studies were reviewed to assess the synergistic effects. Lastly, poly-generation has been introduced for the production of multiple value-added products and for reducing negative environmental impacts. It can be observed that large amounts of escaping pollutants resulting from the lack of aftertreatment units undermine the competitiveness of the incineration process. Pyrolysis and gasification processes of waste tires are complex and costly, but the products are more valuable, highlighting the potential to improve efficiency and profitability by optimizing operation conditions. Energetic co-valorization processes have the advantages of enhancing the quality of products and reducing energy consumption. H2 production is a more common selection favored by the market in poly-generation processes. Some recommendations have been made to address current challenges faced by waste tire energetic valorization including updating the pretreatment techniques to improve overall efficiency, building comprehensive assessment models with consideration of multi-dimensional analysis and sustainable development goals (SDGs), developing superstructure optimization frameworks, and collecting mechanism data to enhance the accuracy of forecasts. This review outlines the achieved advances and future development directions in this field, underscoring the significance of energetic valorization technologies for sustainable waste tires management.