Co-Pyrolysis of Plastic Wastes: Effects of Temperature and Feedstock Ratio on Chemical Composition of Liquid Product

Co-Pyrolysis of Low Density Polyethylene (LDPE) and Polystyrene (PS) was carried out in a semi-batch glass reactor system. Effects of temperature and feedstock ratio on pyrolytic product yields (gaseous, liquid and solid residue) and chemical composition of the liquid were investigated. All experiments were performed with 15 g feedstock in 25 mL/min nitrogen atmosphere and 60 min duration at specified temperature. Temperature was changed from 470 to 620 °C with 50 °C break by utilizing PID controller which was setted 10 °C/min heating rate. PS in the feedstock was varied as 0, 33, 67, 100 wt. %. The liquid products were characterized by GC-MS. When PS and LDPE were mixed equally by weight at 570 °C, liquid product yield was found 85 wt. %. More PS adding in the feedstock did nearly not affect this value. It was detected that hydrocarbons which were aromatic, cyclic and aliphatic formed the peak areas’s majority of the co-pyrolytic liquid. Specifically styrene was found dominant component in that liquid. Besides that, it was observed that with increasing temperature, peak areas’ percentage of alkanes decreased while temperature rising didn’t affect olefines’ peak areas.