Waste tyre valorization by catalytic pyrolysis – A review

The environmental concern associated with waste tyre disposal and the necessity of sustainable waste management policies has promoted the development of waste tyre valorization processes in the last decades. Within this framework, this review analyzes the main advances in waste tyre valorization by catalytic pyrolysis. Waste tyre pyrolysis allows converting this solid waste into three product fractions of potential interest, as are gases, pyrolysis oil (TPO) and char, with their yield and features being conditioned by pyrolysis conditions. Catalytic pyrolysis is an interesting alternative to improve the quality of the products and the selectivity of the process. A wide range of catalysts have been proposed in the literature for waste tyre valorization, with zeolites being the most commonly used due to their capacity for the production of valuable chemicals, such as BTX and light olefins. This review approaches multidisciplinary aspects for the evaluation of the critical points in this process, such as those related to pyrolysis technologies, reaction mechanisms, catalyst design and products properties.