Modeling and optimization of biodiesel from high free‐fatty‐acid chicken fat by non‐catalytic esterification and mussel‐shell‐catalyzed transesterification

Abstract

AbstractBACKGROUNDIn this study, biodiesel was prepared from chicken fat via a transesterification reaction using Mussel shells as a catalyst. Pretreatment of chicken fat was carried out using non‐catalytic esterification to reduce the free fatty acid content from 36.28 to 0.96 mg KOH/g oil using an ethanol/ fat mole ratio equal to 115:1. In the transesterification reaction, the studied variables were methanol: oil mole ratio in the range of (6:1 ‐ 30:1), catalyst loading in the range of (9‐15) wt%, reaction temperature (55‐75 °C), and reaction time (1‐7) h. The heterogeneous alkaline catalyst was greenly synthesized from waste mussel shells throughout a calcination process at different calcination times of (1‐5) h and temperatures of (700‐900) °C. The catalyst was characterized using BET, SEM, EDX, XRD, and FTIR.RESULTSIn the transesterification reaction, the best values of the studied parameters were: 21:1 methanol: oil molar ratio, 12 wt% catalyst loading, 5 h reaction time, and 63°C reaction temperature, which gave 96.2% methyl esters content. For catalyst synthesis, it was found that the optimum calcination conditions were 900 °C and 3 h, which resulted in a specific surface area of 10.5 m2/g and a large pore volume of 0.0033 cm3/g.CONCLUSIONA calcium oxide catalyst was successfully prepared from mussel shells. This catalyst was used to transesterify the chicken fat into biodiesel. The prepared catalyst exhibited a high active surface area and a pore volume, confirming that the CaO catalyst produced from waste mussel shells worked effectively, steadily, and affordably to produce renewable biodiesel. The best working conditions for the transesterification reaction were determined using the central Composite Design method (CCD). © 2023 Society of Chemical Industry.