Characterization of the waxes obtained by the pyrolysis of polyolefin plastics in a conical spouted bed reactor

The thermal pyrolysis of three different polyolefin plastics (HDPE, LDPE and PP) has been carried out in a conical spouted bed reactor. This technology is especially interesting because of the high selectivity to waxes due to the low residence times and high heating rates that reduce secondary reactions and increase the yield of primary pyrolysis products (waxes). These have been obtained operating at 450, 500 and 600 °C and a complete characterization has been carried out using different techniques, such as gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectrophotometry, simulated distillation and the measurement of heating value and melting point. Operating conditions and feed type have been observed to have a significant effect on the properties of the different waxes. The characterization has been carried out bearing in mind the potential use of waste plastic-derived waxes as a feedstock for cracking units.

► Waxes obtained by polyolefin pyrolysis have been characterized. ► GPC, FTIR, simulated distillation, heating value and melting point have been used. ► As higher is the operating temperature lower is the molecular weight and the heavy wax fraction. ► Waxes are predominantly long paraffin hydrocarbons. ► The conical spouted bed reactor is an interesting alternative to obtain high yields of waxes at low temperatures.