Tri-pyrolysis: A thermo-kinetic characterisation of polyethylene, cornstalk, and anthracite coal using TGA-FTIR analysis

Abstract

The tri-pyrolysis of polyethylene (PE), cornstalk (CS) and anthracite coal (AC) was performed using a thermogravimetric analyser (TGA) coupled to a Fourier transform infrared spectrometer (FTIR). The pyrolysis and kinetic characteristics of the raw feed materials (PE, CS and AC) along with selected mass blend ratios was investigated and compared. The tri-pyrolysis process for the selected mass blend ratios is characterised by three distinct stages, which is sequentially dominated by cornstalk CS, polyethylene PE, and anthracite AC. It was found that the activation energies representing the tri-pyrolysis process are different with respect to the activation energies associated with the individual raw feed materials. It is observed that for any given fixed mass blend ratio of PE as the contribution of CS is increased the initial decomposition temperature at which tri-pyrolysis takes place is significantly lowered to <190 °C. Therefore, the increased addition of CS is considered to enhance the tri-pyrolysis process. An increase in the mass blend ratio of AC resulted in higher yields of pyrolysed residue. The yield of tri-pyrolysed residue accounted for up to 40 wt% when the mass blend contribution of AC was ≥0.5. Activation energies of <130 kJ mol−1 for the suite of mass blended materials was determined with little variation in the actual EA’s between the respective mass blend ratios. The tri-pyrolysis reaction is thought to be more stable than the pyrolysis of the individual raw feed materials and it is further suggested that a synergy between the respective feed materials exists during the tri-pyrolysis process.