Colloquia

Summary

Plastic pyrolysis experiments at four different temperatures were conducted at analytical scale, using a Py-GC-MS/FID instrument. The data obtained was analyzed, yielding the pyrolysis product composition. The Mass Spectrometric (MS) chromatogram was used to identify the components in the pyrolysis product, and the Flame Ionization Detector (FID) chromatogram was used to quantify these components.

The identified and quantified components were subsequently converted to PIONAD weight fractions, which were used as the input parameter for the simulation model.  The simulation was performed using Aspen Plus®. This model contained the pyrolysis process and the fractionation section, where the pyrolysis product was separated into three different fractions (gas, oil, and wax).

The obtained mass- and energy balances from the simulation model were used for the life cycle evaluation model, where both the process performance and carbon dioxide emission footprint associated with the process were studied. The advanced recycle value chain framework was applied to the evaluation model, meaning it was further expanded with downstream processing unit operations (e.g., steam cracking and hydroprocessing), providing a complete overview of the pyrolysis process impact from pyrolyzing plastic waste to the production of virgin plastics.

In this study, insights on the influence of pyrolysis temperature on the pyrolysis product composition were provided. Process design was performed, yielding a design concept for the pyrolysis and fractionation processes. This process – including downstream unit operations – was evaluated, providing plastic recovery factors, relative energy consumption performance, and the carbon dioxide emission footprint of the analyzed cycle.