Renewable Hydrocarbon Production from Waste Cottonseed Oil Pyrolysis and Catalytic Upgrading of Vapors with Mo-Co and Mo-Ni Catalysts Supported on γ-Al2O3

In this work, the production of renewable hydrocarbons was explored by the means of waste cottonseed oil (WCSO) micropyrolysis at 500 degrees C. Catalytic upgrading of the pyrolysis vapors was studied using alpha-Al2O3, gamma-Al2O3, Mo-Co/gamma-Al2O3, and Mo-Ni/gamma-Al2O3 catalysts. The oxygen removal efficiency was much lower in non-catalytic pyrolysis (18.0%), whilst gamma-Al2O3 yielded a very high oxygen removal efficiency (91.8%), similar to that obtained with Mo-Co/gamma-Al2O3 (92.8%) and higher than that attained with Mo-Ni/gamma-Al2O3 (82.0%). Higher conversion yields into total renewable hydrocarbons were obtained with Mo-Co/gamma-Al2O3 (61.9 wt.%) in comparison to Mo-Ni/gamma-Al2O3 (46.6%). GC/MS analyses showed a relative chemical composition of 31.3, 86.4, and 92.6% of total renewable hydrocarbons and 58.7, 7.2, and 4.2% of oxygenated compounds for non-catalytic bio-oil (BOWCSO), BOMoNi and BOMoCo, respectively. The renewable hydrocarbons that were derived from BOMoNi and BOMoCo were mainly composed by olefins (35.3 and 33.4%), aromatics (31.4 and 28.9%), and paraffins (13.8 and 25.7%). The results revealed the catalysts' effectiveness in FFA decarbonylation and decarboxylation, as evidenced by significant changes in the van Krevelen space, with the lowest O/C ratio values for BOMoCo and BOMoNi (O/C = 0-0.10) in relation to the BOWCSO (O/C = 0.10-0.20), and by a decrease in the presence of oxygenated compounds in the catalytic bio-oils.

Automated summary

Renewable hydrocarbons were produced from waste cottonseed oil through micropyrolysis, and catalytic upgrading of the pyrolysis vapors was investigated using various catalysts. Results showed that Mo-Co/gamma-Al2O3 catalyst had the highest conversion yields into total renewable hydrocarbons, indicating its effectiveness in the process.