Tyre pyrolysis oil properties and their effect on diesel engine performance, emission and combustion characteristics: A review

Abstract

The rapid growth in the economy of many countries has led to high demand and over dependence on fossil fuels whose reserves are limited. Together with their undesirable environmental emissions, there has been need for identifying alternative fuels that are suitable for the diesel engines. Amongst other fuels, tyre pyrolysis oil (TPO) has been identified as a potential additive or supplement to the diesel fuel. When considering an alternative fuel, many factors are taken into consideration including emissions and performance in diesel engines. In in this review, published work on tyre pyrolysis oil with main focus on its use in diesel engines as an alternative is discussed. Production of tyre pyrolysis oil and the influence of pyrolysis process conditions on TPO yield are discussed. Optimum oil yield obtained during pyrolysis is within the range of 450 - 550oC depending on the reactor conditions. Properties of TPO are also discussed and compared to those of diesel and relevant standards. The effect of TPO and its blends on engine performance with emphasis on fuel consumption, thermal efficiency and emissions are also reviewed. Overall, the diesel engine performs better with low concentration of TPO in the Diesel/TPO blend than with higher concentration of TPO. This is because fuel properties such as such aromatic content, density, viscosity, Sulphur content and low Cetane number are higher compared to diesel.