Investigating the effects of different carrier gases on the pyrolysis of polyethylene terephthalate in the presence of zeolite 4A catalyst

In this study, pyrolysis of polyethylene terephthalate in the presence of helium, nitrogen and argon carrier gases in the presence/absence of zeolite 4A catalyst was investigated. Feedstock was PET Bottle Grade granules and 15 g of that was used in a semi-batch reactor. Experiments were conducted under atmospheric pressure at 500 °C. The results showed that the yields of gaseous and liquid products increased by the catalyst and the rate of increase were different for different carrier gases, so that the highest increase was related to argon carrier gas (12.4% for gas and 4.4% for liquid). In addition, the yields of wax and char reduced in the presence of catalysts. GC-MS results indicated that aromatic compounds were abundant in the tar, but the catalyst and further cracking transformed them into non-aromatic and linear compounds Different results were obtained by different carrier gases. The mass and polarity of the carrier gas had a significant effect on the amount and type of compounds. Due to the heavier weight of argon and lower velocity of volatiles in reactor in its presence, small amount of liquid phase and lighter compounds in it was obtained.