Synthesis of biodiesel via methanolysis of waste frying oil by biowaste-derived catalyst: process optimization and biodiesel blends characterization

• Published in: Biomass conversion and biorefinery 2024, Vol.14 (2), p.1781-1792
• Main Authors: Yusuff, Adeyinka S., Thompson-Yusuff, Kudirat A., Igbafe, Anselm I.
• Format: Article
• Language: English
• Subjects: Biodiesel fuels; Biotechnology; Catalysts; Diesel engines; Differential thermal analysis; Energy; Frying; Methanol; Optimization; Original Article; Orthogonal arrays; Process parameters; Production costs; Renewable and Green Energy; Roasting; Synthesis; Taguchi methods; Transesterification; Triglycerides
• ISSN: 2190-6815; 2190-6823
• DOI: 10.1007/s13399-022-02389-1

Heterogeneously catalyzed transesterification reaction is known to be the most appropriate process for producing biodiesel from triglyceride-containing feedstock as it ensures catalyst reusability and easy product separation, lowers production costs, and makes biodiesel affordable. This work investigates the influence of calcination temperature (700–1000 °C) on the performance of CaO catalyst obtained from eggshells for biodiesel synthesis from waste frying oil (WFO). The prepared CaO catalyst was characterized using various techniques (TGA/DTA, N 2 adsorption–desorption isotherm (BET), FTIR, CO 2 -TPD, XRF, XRD, and SEM). Taguchi optimization method with an orthogonal array was used to investigate the effect of process parameters (time, catalyst amount, methanol/oil ratio, and temperature). Reaction time was observed to be the most influential variable according to the design. Under the optimal transesterification conditions (i.e., at 50 °C for 3 h using WFO/methanol molar ratio of 1:10 with catalyst dosage of 0.75 wt.%), the biodiesel yield attained 90.81% when eggshell derived-catalyst calcined at 850 °C (CEG-850) was used. The remarkable performance of the CEG-850 could be attributed to its high basic strength (749  μ mol/g), improved surface area (15.4 m 2 /g), and dominance of basic sites on its surface. The blended fuel with 10% by volume biodiesel (B10) exhibited improved fuel properties compared to blended fuel with 50% by volume biodiesel (B50), which confirmed the suitability of a low-level biodiesel blend in the diesel engine. More than 54% biodiesel yield was achieved after the seventh cycle, depicting better stability.