Synergistic interaction between scrap tyre and plastics for the production of sulphur-free, light oil from fast co-pyrolysis

Fast co-pyrolysis offers a sustainable solution for upcycling polymer waste, including scrap tyre and plastics. Previous studies primarily focused on slow heating rates, neglecting synergistic mechanisms and sulphur transformation in co-pyrolysis with tyre. This research explored fast co-pyrolysis of scrap tyre with polypropylene (PP), low-density polyethylene (LDPE), and polystyrene (PS) to understand synergistic effects and sulphur transformation mechanisms. A pronounced synergy was observed between scrap tyre and plastics, with the nature of the synergy being plastic-type dependent. Remarkably, blending 75 wt% PS or LDPE with tyre effectively eliminated sulphur-bearing compounds in the liquid product. This reduction in sulphur content can substantially mitigate the release of hazardous materials into the environment, emphasizing the environmental significance of co-pyrolysis. The synergy between PP or LDPE and tyre amplified the production of lighter hydrocarbons, while PS's interaction led to the creation of monocyclic aromatics. These findings offer insights into the intricate chemistry of scrap tyre and plastic interactions and highlight the potential of co-pyrolysis in waste management. By converting potential pollutants into valuable products, this method can significantly reduce the release of hazardous materials into the environment.

Catalytic Pyrolysis of the Green Microalgae Botryococcus braunii over Ni/SBA-15 Prepared by the Ultrasonic-Assisted Sol-Gel Method

The pyrolysis of the green microalgae Botryococcus braunii in the absence and the presence of Ni/SBA-15 prepared by the ultrasonic-assisted sol-gel was investigated using pyrolysis-gas chromatography-mass spectroscopy (Py-GC/MS). Pyrolysis experiments were performed at 350, 450, and 550 °C under helium (He) flow. In the absence of a catalyst, the chemical composition of pyrolysis products at different temperatures, based on the relative peak area, comprised protein/amino acid derivative products of 9-15%, carbohydrate derivative products of 5-10%, lipid derivative products of 13-26%, and chlorophyll derivative products of 24-26%. For catalytic pyrolysis, the chemical composition of pyrolysis products comprised protein/amino acid derivative products of 5-15%, carbohydrate derivative products of 18-19.5%, lipid derivative products of 14-27%, and chlorophyll derivative products of 15-20%. The addition of 10% Ni/SBA-15 enhanced the production of aromatic compounds, such as furans, furfurals, alkyl aromatics, and nitrogen aromatic compounds. These were the thermal degradation products of carbohydrates and proteins. However, the amount of fatty acids and phytol fragments in the pyrolysis of Botryococcus braunii decreased in the presence of catalyst. Thermogravimetric analyses showed that the temperature range for the pyrolysis of Botryococcus braunii was 135-547 °C, while that of the catalyzed pyrolysis was 135-532 °C. There was a decrease in pyrolysis yield after incorporating Ni/SBA-15, which may be due to coke formation.

Kinetic Study of Copyrolysis of the Green Microalgae Botryococcus braunii and Victorian Brown Coal by Thermogravimetric Analysis

The copyrolysis of the green microalgae Botryococcus braunii and Victorian brown coal was studied by thermogravimetric analysis using the Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Friedman methods. This research aims to study the synergistic effect of mixing B. braunii and Victorian brown coal in pyrolysis reactions on the kinetic parameter using thermogravimetric analysis. Copyrolysis was carried out at four heating rates, 10, 15, 20, and 25 °C/min. The copyrolysis reaction of B. braunii and Victorian brown coal occurred from 155.79 to 545.27 °C; this temperature range was lower than that for the pyrolysis of only B. braunii under the same conditions. However, mixing the two samples increased the thermal decomposition temperature for each conversion value (α), as well as the average activation energy, due to the presence of compounds that require high temperatures to undergo pyrolysis in the Victorian brown coal. The average activation energies of the copyrolysis reaction of B. braunii and Victorian brown coal determined using the KAS, FWO, and Friedman methods were 195.20 ± 17.40, 195.60 ± 17.70, and 225.93 ± 32.39 kJ/mol, respectively.