Theoretical investigation of combustion and emissions of CI engines fueled by various blends of depolymerized low-density polythene and diesel with co-solvent additives

Abstract

The depletion of fossil fuels and the accumulation of plastic waste are both serious issues facing the world today. This study investigated the potential use of plastic waste as an alternative fuel by utilizing diesel (D) to depolymerize low-density polyethylene (LDPE) in the presence of co-solvents. Several co-solvents were examined: a-pinene, toluene, and o-xylene, with ratios of 10% weight in the LDPE/diesel blend. The blends were theoretically tested in a diesel engine to investigate the impact on the combustion characteristics and emissions. According to tested data, the in-cylinder peak pressure and temperature decreased within the blend of D/LDPE in comparison to diesel at all engine loads. However, when co-solvents were added to the D/LDPE blend, in-cylinder pressures increased during the combustion at all loads, with improvements of 0.48%, 0.5%, 0.6%, and 0.4% for the blends of D/LDPE (10% toluene and 1 bar), D/LDPE (10% a-pinene and 1 bar), D/LDPE (10% xylene and 1 bar), and D/LDPE (10% xylene and 10 bar), respectively, in comparison with diesel at 100% load. Co-solvent additions such as a-pinene and o-xylene to the plastic/diesel blend resulted in a substantial and gradual increase in the heat release rate at high loads. In respect to emissions, carbon monoxide, unburnt hydrocarbon, and soot levels were raised by adding LDPE plastic to D and reduced by adding co-solvents. The most effective co-solvents for decreasing carbon monoxide, unburnt hydrocarbon, and soot emissions were pinene, followed by xylene.