The Thermochemical Processing of Municipal Solid Wastes: Thermal Events and the Kinetics of Pyrolysis

Abstract

Thermal events and kinetics for the pyrolysis of binary mixtures constituted by equal proportions of polyethylene and some other representative components of municipal solid wastes—cellulose, lignin, sawdust from a native wood species—are characterized by thermogravimetry from room temperature up to 750°C. Results for the individual municipal solid waste components show that pyrolysis of polyethylene and cellulose begins at higher temperatures, proceeding more sharply than for lignin and the wood sawdust and also attaining the highest reaction rates. Two well-distinguishable peaks characterize the reaction rate profiles of the simulated mixtures, with the one corresponding to polyethylene taking place at a higher temperature. They point to negligible interactions between the components of the mixtures. The reaction rate profiles are properly described by an overall first-order decomposition model, which enables to evaluate kinetic parameters for the investigated polyethylene-based mixtures. Differences in their pyrolytic behavior, depending on the individual municipal solid waste constituent accompanying polyethylene, are reflected in the estimated kinetic parameters.

Keywords:

• kinetics
• municipal solid wastes
• polyethylene-based mixtures
• pyrolysis
• thermal degradation

Notes

^a Estimated by difference.