Recovering wax from polyethylene waste using C-DPyR

In this work, a new concept of an energetically self-sustaining pyrolysis reactor, C-DPyR, is presented as an alternative to transforming polyethylene waste into wax. TGA and DSC were used to characterize the wax regarding thermal behavior among the recovered materials and perform kinetics computations. ATR-FTIR identified the functional groups constituting the waxes. The experiments that reached great thermal energies resulted in a high amount of gas produced, on average of 74 wt%, confirming that pyrolysis's heat was more than sufficient to crack the samples. A maximum of about 87 wt% of wax was recovered from an experiment that made 80 kJ of energy available for pyrolysis. It was assumed that the wax degrades through overlapped reactions associated with the main functional groups forming the wax and identified by FTIR. DSC curves evidenced one endothermic valley, 80 J/g, and one exothermic peak, 2115 J/g. The FTIR established the functional wax groups composed mainly of C-H, CH2, and CH3, the same groups present in the FTIR spectra of LDPE. Using isoconversional methods, the wax pyrolysis's single-step and multi-step kinetic analyses were performed to determine the kinetic triplets. The TGA curves were accurately reconstructed for both approaches, confirming reliable kinetic predictions. Although C-DPyR promises effective thermal energies to drive pyrolytic processes, it is yet most suitable for converting materials that do not require strictly controlled temperatures.