Kinetic studies on waste cooking oil into biodiesel via hydrodynamic cavitation. (10th March 2017)

• Record Type: Journal Article
• Authors: Chuah, Lai Fatt; Klemeš, Jiří Jaromír; Yusup, Suzana; Bokhari, Awais; Akbar, Majid Majeed; Chong, Zhi Kai
• Is Part Of: Journal of cleaner production. Volume 146(2017)
• Page Start: 47
• Page End: 56
• Publication Date: 2017-03-10
• Subjects: Operating parameters -- Kinetic parameters -- Mass transfer -- Hydrodynamic cavitation; CO2 Carbon dioxide -- FU Functional unit -- WCO Waste cooking oil -- WCOME Waste cooking oil methyl ester -- HC Hydrodynamic cavitation -- TG Triglyceride -- DG Diglyceride -- MG Monoglyceride -- MS Mechanical stirring -- FFA Free fatty acid -- KOH Potassium hydroxide; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2016.06.187
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Development of cleaner biodiesel production related to hydrodynamic cavitation of methyl ester synthesis from sustainable waste cooking oil via alkali-catalysed transesterification is gaining importance due to considerable lower energy requirement and time. The effects of the oil to methanol molar ratio (1:4–1:7), catalyst concentration (0.5–1.25 wt %) and reaction temperature (50–65 °C) have been studied in a hydrodynamic cavitation and mechanical stirring system. Highest conversion of 98% was achieved under optimum conditions of 1:6 M ratio of oil to methanol, 1 wt % potassium hydroxide as alkali catalyst, 60 °C and 15 min reaction time. It has been observed that yield efficiency and reaction time were 833% higher and 600% shorter using hydrodynamic cavitation compared to mechanical stirring. Triglycerides conversion obeys pseudo-first order mechanism. The kinetic parameters of hydrodynamic cavitation and mechanical stirring were calculated, where the reaction rate constants were 0.238 and 0.031 min −1, activation energies were 89.7 and 92.7 kJ/mol and the pre-exponential factors were 2.623 × 10 ​13 and 1.120 × 10 ​13 min −1 . Hydrodynamic cavitation was 1.8 fold more energy efficient and 4.6 fold lower feedstock used per produced product than mechanical stirring in biodiesel production. In conclusion, waste cooking oil methyl ester produced via hydrodynamic cavitation proved to be time saving and energy efficient compared to mechanical stirring. This makes the process more environmental friendly using hydrodynamic cavitation. Highlights: About 7.7 fold higher rate constant using HC compared to mechanical stirring. About 2.3 fold higher frequency factor using HC than mechanical stirring. The activation energy for HC and mechanical stirring were 89.7 and 92.7 kJ/mol. About 4.6 fold lower feedstock per product using HC than mechanical stirring.