Inhibitory effect of thyme oil as an antioxidant for waste cooking oil biodiesel crystallization. Issue 1 (February 2023)

• Record Type: Journal Article
• Authors: Uguz, Gediz
• Is Part Of: Energy & environment. Volume 34:Issue 1(2023)
• Page Start: 176
• Page End: 192
• Publication Date: 2023-02
• Subjects: Antioxidant -- biodiesel -- inhibitory effect -- thyme oil -- waste cooking oil; Power resources -- Environmental aspects -- Periodicals; Power resources -- Periodicals; Renewable energy sources -- Periodicals; Energy policy -- Environmental aspects -- Periodicals; Ressources énergétiques; Politique énergétique; Energy policy -- Environmental aspects; Power resources; Power resources -- Environmental aspects; Renewable energy sources; Periodicals; 333.7
• DOI: 10.1177/0958305X211061346
• Languages: English
• ISSNs: 0958-305X

Abstract

The effects of thyme oil extract as an antioxidant on crystallization properties of waste cooking oil biodiesel were investigated. The inhibitory effect was determined for ASTM D7545 standard method for biodiesel added with 1000, 2000, and 3000 ppm of additives by using oxifast device and compared with the chemical antioxidant butylated hydroxytoluene (BHT). Inhibition time data were determined by converting the oxidation stability analysis results. The crystallization temperatures (Tcr ) of the samples were determined by using a Differential Scanning Calorimetry (DSC) technique. Tcr values of samples with antioxidants were decreased compared to the non-antioxidant biodiesel sample (B100). The order of antioxidant power was B100<B100T1<B100T2 = B100BHT1<B100BHT2<B100T3<B100BHT3. The solid fat content (SFC %) values were determined with different antioxidant concentrations versus different times. The minimum SFC % was determined in B100T3 and B100BHT3 in 3000 ppm antioxidant concentrations in 720 min. DSC results show that the crystallization onset temperatures for B100, B100T3, and B100BHT3 were −51.83 °C, −53.59 °C, and −54.15 °C, respectively. The kinetics of crystallization was determined and k and n values were calculated. The addition of thyme oil extract as a natural antioxidant has a positive effect on biodiesel oxidative stability for all concentrations.