Scope of Pyrolysis Process as a Sustainable Method to Dispose Waste Tires: A Review

Abstract

Vehicles on roads are increasing tremendously and so are the waste and pollution. Every year billions of waste tires are being produced which is either left as such as solid waste or used for land fillings or burnt. Open tire fires are polluting air by emitting carbon monoxide, sulfur dioxide, oxides of nitrogen, organic pollutants, and poly-aromatic hydrocarbons (PAH). These gases can have chronic health affects like skin rashes, irritation of eyes, and respiratory problems. There is a growing concern for development of sustainable waste tire disposable methods. Tire being a polymer can be subjected to pyrolysis process to derive feedstock materials. It was found by many researchers that the products from pyrolysis can be used in different applications. There are three main products of pyrolysis of tires, namely gaseous products, liquid products, and the solid product called as char. These products when collected properly could be used for various other purposes. The gaseous products mainly consist of hydrogen, lighter hydrocarbons (HC), and carbon monoxide. These gases have the potential to generate energy. The liquid products when distilled produce gasoline like fuel and diesel like fuel. Char being porous can act as a gasification catalyst and when upgraded can be used to generate carbon black (CB) which is reutilized in manufacturing of tires. Also, for tire pyrolysis to be a sustainable process for disposing tires, hybrid technologies at industrial scale have to be explored. This paper provides an insight on tire pyrolysis processes and a detailed overview on latest research being done on the products of pyrolysis stating the use of these products to make the pyrolysis process economically viable.