An experimental assessment on dual fuel engine behavior powered by waste tire-derived pyrolysis oil – biogas blends

This paper is intended to investigate the usability of waste tire pyrolysis oil along with diesel and biogas dual fuel in the CI engines. In this framework, the waste tire chips are firstly pyrolyzed in the study, and then are volumetrically blended into the conventional diesel fuel (DF) at the ratio of 20%. The biogas flow rate changes as 0.5, 1, and 2 L/min when the engine is fuelled by P20 test fuel. Throughout the experiments, the engine runs at a fixed engine speed of 1500 rpm under 2.5, 5, 7.5 and 10 Nm. In the results, it is noticed that the unburnt emissions such as CO and HC considerably increases with the presence of pyrolysis oil and biogas in the cylinder due to the lack of oxygen and lower heating value of these fuels. However, the NOx firstly rises with the diesel-pyrolysis oil blends by 2.21% but then pulls back with the introduction of biogas to the combustion chamber. It drops by 2.29%, 4.93%, and 11.14% for P20 + 0.5 BG, P20 + 1 BG, and P20 + 2 BG test fuels, respectively in comparison to that of DF. On the other hand, the engine performance worsens with the pyrolysis oil due to the lower energy content. Accordingly, the increment on BSFC is found to be 9.28%, 25.15%, 42.51%, and 67.68%, and the reduction on BTE is found to be 8.47%, 17.72%, 25.52%, and 33.48% for P20, P20 + 0.5 BG, P20 + 1 BG, and P20 + 2 BG test fuels, respectively. It is concluded that even if they worsen the engine performance and exhaust emissions, the burning of waste products in the forms of pyrolysis oil and biogas as fuel substitutions in CI engines seems a very promising way in terms of waste management, disposal the huge volume of waste products from the nature, and protection of rapidly depletion fossil fuel reserves.