Recovering value-added hydrocarbons from aluminum foil-laminated plastic residue through catalytic pyrolysis using WO3 supported on rice husk ash

Abstract

Following a circular economy strategy, recovering value-added hydrocarbons from plastic residues through catalytic pyrolysis is an innovative and promising approach for both resource conservation and refuse valorization. The main objective of the current work is to investigate the impact of tungsten trioxide (WO₃) supported on rice husk ash (RHA) as a new, low-cost catalyst on the flash pyrolysis of aluminum foil-laminated plastic residue. The catalyst performance was investigated using a micro-furnace temperature-programmable pyrolyzer interfaced with gas chromatographic separation and mass spectrometry detection. The energy-related attributes of aluminum foil-laminated plastic residue have confirmed its potential as raw material for pyrolytic oil production, owing to its high energy content (31.76 MJ kg⁻¹), volatile matter content (82.5 wt%), moderate ash content (17.5 wt%), negligible fixed carbon content (below 0.01 wt%), and predominant mass loss below 500 °C. The catalytic test results demonstrated that the concentration of alkanes increased by 2.5-fold and cyclic aliphatic compounds by 1.9-fold when utilizing the WO₃/RHA catalyst compared to non-catalytic pyrolysis. From the hydrocarbon distributions, success was achieved by the WO₃/RHA catalyst in the cracking of heavy hydrocarbons (above C₁₂) into valuable light hydrocarbons (C₅–C₁₂). The results permit us to conclude that utilizing the WO₃/RHA catalyst enhances the yield of alkanes and cyclic aliphatic compounds within the C₅–C₁₂ range in the condensable volatile products, which are valuable gasoline-range hydrocarbons. Utilizing the proposed catalyst offers a potentially low-cost way to convert plastic waste into gasoline-range transportation fuel, enabling the achievement of a circular economy for plastic residues through catalytic pyrolysis, unlike traditional treatment methods.