Characterization of Char Produced from PET Plastic Pyrolysis: Effect of Temperature on Calorific Value and Moisture Content

¹ Department of Automotive Engineering Technology, Faculty of Engineering, Universitas Muhammadiyah Yogyakarta, 55183 Indonesia
² Department of electronic-medical Technology, Faculty of Engineering, Universitas Muhammadiyah Yogyakarta, 55183 Indonesia
³ Department of Electrical Engineering Education, Universitas Negeri Yogyakarta, Indonesia
⁴ International Center for AI and Cyber Security Research and Innovations, Asia University, Taiwan

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

The increasing accumulation of polyethylene terephthalate (PET) plastic waste poses a significant environmental challenge due to its resistance to degradation and limited recycling pathways. Pyrolysis has emerged as a promising thermochemical method for converting PET waste into valuable byproducts, including energy-dense char. This study investigates the effect of pyrolysis temperature on the calorific value and moisture content of char produced from PET plastic under a fixed residence time of 60 minutes. Experiments were conducted at three temperatures 200°C, 300°C, and 400°C using a stainless-steel batch reactor under a nitrogen atmosphere. The results showed a clear trend: higher temperatures significantly enhanced the char’s quality. At 400°C, the char exhibited a calorific value of 27.4 ± 0.2 MJ/kg and a moisture content of 2.8 ± 0.1%, compared to 18.2 ± 0.1 MJ/kg and 7.5 ± 0.1% at 200°C. These improvements are attributed to increased devolatilization and aromatization processes that enhance fixed carbon content and thermal stability. Statistical analyses ANOVA confirmed that the differences across temperatures were highly significant (p < 0.001). While the results demonstrate that PET-derived char has potential as an alternative solid fuel, the study is limited to calorific and moisture characteristics. Further research is recommended to evaluate additional properties such as ash content, combustion emissions, and real-world fuel performance. Overall, this work contributes to the growing body of knowledge on plastic-to- energy conversion and supports the development of sustainable waste management technologies.