Multivariate combined optimization strategy and comparative life-cycle assessment of biomass and plastic residues via microwave co-pyrolysis approach towards a sustainable synthesis of renewable hydrocarbon fuel

The present study revealed the optimum co-pyrolysis process condition and simultaneously evaluated the environmental impact potential during co-valorisation of electronic plastic waste (WEEP) with Hydnocarpus de-oiled seed cake (HDSC) to produce renewable hydrocarbon fuel. In this work, the primary co-pyrolysis process parameters such as operating temperature, mixture ratio, and catalyst loading were modeled and optimized using a combined approach of both Response Surface Methodology (RSM) and Artificial Neural Network (ANN). In the optimized condition, a maximum pyrolysis oil yield of 30.79 wt% was achieved at an operating temperature of 530 °C, a mixture ratio of 0.49, and catalyst loading of 20 wt%. The obtained co-pyrolysis products were characterized to evaluate their physiochemical properties. Finally, a detailed life cycle assessment (LCA) of the scaled-up microwave-assisted co-pyrolysis plant has been modeled, and the result revealed that the emission levels of 771.95 kg CO2 eq, 3.11 kg SO2 eq, 1.69 kg PO4 eq, 338.59 DCB eq, and 0.11 kg C2H4 eq were projected for processing 1 tonne of feedstock. Further, sensitivity analysis revealed that a decrease of 15% in electricity consumption results in a reduction of the overall environmental impact by 13.69%. Above results demonstrate that microwave co-pyrolysis of biomass with plastic waste holds great potential for positive energy production and negative emission technology when compared to other waste management methods. Hence, this investigation paves the way for the sustainable conversion of e-waste plastic and biomass residue into renewable fuel and helps to achieve the sustainability goal of reducing GWP emissions.