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

The effect of copyrolysis operating conditions, namely, temperature (500-650 degrees 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 degrees C, a N-2 flow 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 degrees 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 beta-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.

Automated summary

This study investigates the influence of copyrolysis operating conditions and copper doping on the product distribution of sugarcane leaves (SCLs) and low-density polyethylene (LDPE) pyrolysis. The results show that there is a synergistic effect on liquid yield when co-pyrolyzing biomass-plastic mixtures. However, the experimental yield of noncondensable gas is higher than the theoretical yield at high temperature. Moreover, the amount of copper doped into HZSM-35 has an insignificant effect on the product yield.