Catalytic Copyrolysis of Sugarcane Leaves and Low-Density Polyethylene Waste to Produce Bio-Oil and Chemicals Using Copper-Doped HZSM-35

Abstract

The effect of copyrolysis operating conditions, namely, temperature (500-650 °C), inert nitrogen flow rate (80-200 mL min-1), reaction time (30-75 min), and copper metal-doped HZSM-35, was examined on the product distribution and compared when different mass ratios of sugarcane leaves (SCLs) and low-density polyethylene (LDPE) were pyrolyzed with different concentrations of copper (wt %) doped into HZSM-35. The optimal bioproduction conditions were as follows: 550 °C, a N2flow rate of 120 mL min-1, a reaction time of 45 min, an SCL/LDPE mass ratio of 0.8:0.2, and the use of 0.4% Cu-ZSM-35. A synergistic effect on the liquid yield was observed when co-pyrolyzing the biomass-plastic mixture from 500 to 600 °C. In contrast, the experimental yield of noncondensable gas was higher than the theoretical yield at high temperature. The effect of the amount of copper doped into HZSM-35 on the product yield was insignificant, but gas chromatography-mass spectrometry analysis allowed both thermal degradation and catalytic effects on C-C cleavage due to the decomposition of volatile vapors and the occurrence of β-scission to produce aliphatics. These aliphatics were further cracked into smaller hydrocarbons; thus, the relative hydrocarbon content increased. This study demonstrates that a synergistic effect occurs between the catalytic reactions, such as deoxygenation, and pore selectivity to enhance the production of high-quality bio-oil. Furthermore, valuable chemical feedstocks can be obtained from the catalytic copyrolysis of the biomass-plastic mixture with a copper metal-doped hierarchical ZSM-35 catalyst. © 2022 American Chemical Society. All rights reserved.