In-situ and ex-situ co-pyrolysis studies of waste biomass with spent motor oil: Elucidating the role of physical inhibition and mixing ratio to enhance fuel quality.

Simultaneous renewable energy generation is an imperative part of sustainable hazardous waste management. Therefore, the present work explicates the co-pyrolysis of rice stubble (RS) waste biomass and spent motor oil (SMO) to upgrade the obtained bio-oil. Moreover, two different modes, namely, in-situ and ex-situ, were implemented to analyze the effect of physical inhibition. Monothetic analysis approach was followed to determine optimum process conditions. A substantial increment of âˆ¼ 85% was observed in bio-oil yield for RS: SMO (1:1) in-situ operation whilst the only RS biomass pyrolysis. Moreover, the HHV increased by âˆ¼ 2.15 times after co-pyrolysis with a considerable reduction (62.70%) in water content. Consequently, the paraffin content increased to 79.14 vol% with an iso-paraffin index of 0.285. Subsequently, a possible reaction mechanism is also proposed to evaluate results comprehensively. Altogether, the co-pyrolysis of these feedstocks resulted in improved aliphatic content and reduced oxygenates, encouraging its adequacy as an alternate fuel.