Towards green mobility: investigating hydrogen-enriched waste plastic biodiesel blends with n-butanol for sustainable diesel engine applications†

Abstract

This study examines the performance of pyrolyzed waste plastic biodiesel (WPO) in a compression ignition engine when combined with n-butanol and enriched hydrogen (H₂). Initially, low-density polyethylene (LDPE) plastic waste underwent conversion into waste plastic biodiesel via a pyrolysis thermochemical process. Experiments were conducted to evaluate blends consisting of 30% and 40% waste plastic biodiesel. In order to enhance the physical properties of the WPO, an additive consisting of 5% n-butanol (nBut5) was introduced, with the objective of improving combustion performance and minimizing exhaust emissions. Furthermore, enriched hydrogen was delivered to the combustion chamber via the inlet manifold at flow rates of 8 and 10 liters per minute (lpm). The findings indicated that the 40% WPO combined with 5% n-butanol demonstrated combustion properties that are similar to those of traditional diesel fuel. Moreover, the integration of the 40 WPO + nBut5 blend with 10 lpm enriched hydrogen resulted in a notable reduction in brake specific fuel consumption (BSFC) by 20.89% and an enhancement in brake thermal efficiency (BTE) by 8.22%, alongside a decrease in exhaust emissions, which included a reduction in carbon monoxide (CO) by 43.84%, unburned hydrocarbons (UBHC) by 57.8 ppm, and smoke opacity by 14.70%. Nonetheless, there was a notable increase in nitrogen oxide (NO_x) emissions, which went up by 236 ppm when compared to conventional diesel fuel.