Slow pyrolysis of low-density Poly-Ethylene (LDPE): A batch experiment and thermodynamic analysis

Abstract

This research investigates the catalytic effect of activated charcoal, MgCO3, and ZSM-5 in a batch-pyrolysis reactor with a Low-Density Poly-Ethylene (LDPE) feedstock on pyro-oil yield. Initially, trials with the ZSM-5 catalyst were conducted at various temperatures ranging from 300 to 600 °C, in which 500 °C temperature offered a higher pyro-oil yield. Further, similar experiments were carried out with activated charcoal and MgCO3 at 500 °C. The qualitative and quantitative analysis of pyro-oil was done using GC/MS, DSC, TGA, and FTIR techniques. In GC/MS and FTIR, the range of hydrocarbon lying in C5 – C35 for aliphatic, aromatic, and phenolic groups. Moreover, the thermal stability of pyro-oil is found to be 350 °C and decreased by 10%–450 °C from TGA studies. The elemental analysis of char (C90.08% H9.82% N0.10%) and gas composition of pyro-gas were also studied. Additionally, thermal calculations were done for mass balance, energy balance, and exergy balance at various temperatures and found to be in good agreement with the input and output parameters. As per findings, the pyrolysis studies at 500 °C with LDPE feedstock and ZSM-5 catalyst showed higher pyro-oil yields than other tested catalysts under similar conditions.