Pyrolysis of Crumb Tire Rubber Obtained from Waste Largesized Tires of Trucks

Abstract— Pyrolysis of various fractions of crumb rubber (with particle sizes of 0–1, 1–3, 2–3.5, and 2–4 mm) obtained from the waste largesized tires was studied in the temperature range of 550–700°C and at atmospheric pressure. It is shown that in the temperature range under study, the particle size of crumb tire rubber has only an insignificant effect on the distribution of its pyrolysis products, which consist of pyrolysis gas, pyrolysis liquid, and solid carbon residue. Pyrolysis gas is a mixture of predominantly light hydrocarbons of composition C₁–C₄ and hydrogen, the concentration of which increases with a rise in the heat treatment temperature; pyrolysis gas can be utilized as a fuel of the high heating value (HHV), and can also serve as a raw material for hydrogen production. The pyrolysis liquid is a mixture of alicyclic, aromatic, and linear hydrocarbons of С₈–С₁₇ composition with a rather high content of value-added products, such as limonene (up to ~35.5 wt %) and cymene (up to ~14.5 wt %); after their separation, the pyrolysis liquid can be used as heating oil or as a raw material for the production of motor fuels and valuable chemical compounds. The solid carbon residue has a relatively developed mesoporous structure (with a predominant pore size in the range of ~200–400 Å) and can be used as a raw material for the production of carbon sorbents.