Catalytic pyrolysis of waste polypropylene using low-cost natural catalysts

A I Eldahshory; Karim Emara; M S Abd-Elhady; M A Ismail

doi:10.1038/s41598-023-37769-8

Catalytic pyrolysis of waste polypropylene using low-cost natural catalysts

Sci Rep. 2023 Jul 20;13(1):11766. doi: 10.1038/s41598-023-37769-8.

Authors

A I Eldahshory¹, Karim Emara², M S Abd-Elhady^{3

4}, M A Ismail²

Affiliations

¹ Department of Mechanical Engineering, Faculty of Engineering, Beni-Suef University, Beni-Suef, Egypt. ahmedibrahim@eng.bsu.edu.eg.
² Department of Mechanical Engineering, Faculty of Engineering, Helwan University, Helwan, Egypt.
³ Department of Mechanical Engineering, Faculty of Engineering, Beni-Suef University, Beni-Suef, Egypt.
⁴ Mechatronics Department, Faculty of Engineering and Materials Science, German University in Cairo (GUC), Cairo, Egypt.

Abstract

The objective of this research is to produce oil from the catalytic pyrolysis of waste polypropylene (WPP) using a low-cost natural catalyst. Three natural catalysts were examined, i.e. Kaolin, Hematite, and white sand. Different catalyst-to-plastic ratios were examined, i.e. 1:1, 1:2, 1:4, 1:6, and 1:8. The utilized catalysts were elementally analyzed using the XRF analysis and the surface area was analyzed by the BET multi-point method. The WPP thermal degradation behavior was investigated by the thermogravimetric analysis (TGA), then the generated liquid oil was analyzed using the gas chromatography-mass spectrometry (GC-MS) and the differential scanning calorimetry (DSC). Thermal cracking without a catalyst produced a yield of 70 wt% of liquid oil, and the maximum oil yield in case of using Hematite and white sand as a catalysts were 70 wt% and 68 wt%, respectively. However, the ratio of 1:2 of the Kaolin to the WPP produced the highest oil yield of 80.75 wt%, and the ratio of 1:8 of the white sand to the WPP produced the highest gas yield, i.e. 44 wt%. Using Kaolin in the catalytic pyrolysis of WPP produced oil with the lowest percentage of heavy oils, i.e. 25.98%, and the highest percentage of light oils, which is 25.37%, when compared to other catalysts such as Hematite and white sand. Kaolin has the lowest cost of oil production compared to Hematite and white sand, which is 0.28 $/kg of oil. Kaolin is an economical catalyst that improves the quality, as well as the quantity of the produced oil in comparison to Hematite, white sand and the non-catalytic case.