Synergistic recovery of renewable hydrocarbon resources via microwave co-pyrolysis of biomass residue and plastic waste over spent toner catalyst towards sustainable solid waste management

Abstract

The present study unveiled the effect of operating temperature, blending ratio and catalyst addition on the product distribution during microwave co-pyrolysis of Hydnocarpus de-oiled seed cake (HDSC) and Waste electrical and electronic plastic (WEEP). In this work, a new approach of “treatment of wastes with waste” was proposed by converting spent toner powder into a low-cost catalyst. Initially, co-pyrolysis process was conducted in which the operating temperature were changed to 450, 500, and 550 °C corresponding to HDSC:WEEP mixture ratios of 100:0, 75:25, 50:50, 25:75, 0:100. The result shows that oil phase yield was significantly higher for 50:50 mixture ratio and this condition further selected for addition of catalyst. The catalytic co-pyrolysis result shows that produced oil have a density of 0.862 g/mL, high calorific value of 39.51 MJ/kg and viscosity 2.71 cSt which is comparable to commercial diesel fuel. The GC-MS study discovered that addition of catalyst could significantly suppress the oxygen and nitrogen compounds while promote the formation of aromatic hydrocarbons through Diels-Alder reaction mechanism. Finally, techno economic analysis revealed that 1000 kg/h plant demonstrated to be economically viable, with minimal production cost (USD 0.53/L compared to USD 1.15/L of commercial diesel fuel price in India).