Biodiesel synthesis using spent FCC catalyst and CaO from a mixture of sunflower oil and oleic acid

• Published in: Bioresource technology reports 2024-02, Vol.25, p.101714, Article 101714
• Main Authors: Vishnulal, K.S., Ramadesigan, Venkatasailanathan, Seethamraju, Srinivas
• Format: Article
• Language: English
• Subjects: Biodiesel; Calcium diglyceroxide; Heterogeneous catalysts; Spent FCC catalyst; Waste cooking oil
• ISSN: 2589-014X; 2589-014X
• DOI: 10.1016/j.biteb.2023.101714

A physical mixture of two heterogeneous catalysts, calcium oxide (CaO) and spent fluid catalytic cracking (SFCC) catalyst, was used to produce biodiesel from a mixture of refined sunflower oil (RSFO) and 5 wt% oleic acid. The reaction was performed with a 6: 1 M ratio of methanol to oil at 65 °C and 3 wt% catalyst loading. The SFCC catalyst loading was also varied to investigate its effect on soap formation and biodiesel production. The presence of the SFCC catalyst reduced the reaction time from 14 h to 7 h to achieve conversion >99 %. It also decreased the soap formation compared with the reaction catalyzed by CaO alone. The lowest oleic acid conversion to soap (~20%) was obtained for CaO + 20 % SFCC case. Calcium diglyceroxide (CaD) was also tested as a catalyst – it further reduced the reaction time to 1 h for 99 % conversion. [Display omitted] •Mixture of sunflower oil and oleic acid used as a surrogate for waste cooking oil.•Biodiesel synthesis using a physical mixture of spent FCC and CaO catalysts•Calcium diglyceroxide acts as active species and reduces the induction period.•Use of spent FCC catalyst reduces the soap formation from oleic acid.•Soap formation and reaction conversion quantified by TGA and NMR, respectively.