Two-step biodiesel production using high free fatty acid containing pig fat

ABSTRACT

The aim of the study was to produce biodiesel from animal oil as non-edible feedstock. Three different concentrations of oils were used to produce the biodiesel. The main characteristic of these oils was high-free fatty acid content. The oils were transesterified with acid and basic catalysts, respectively. Biodiesel yield of 90 wt.% was obtained by acid transesterification (9 wt.% HCl, 6:1 methanol: oil molar ratio, 60°C, 46 h). Pre-esterification conditions were studied using different oils and acid catalysts: 0.6 wt.% HCl, 6:1 methanol: oil molar ratio at 60°C for 4 h, and this resulted in oil with an acid value of less than 0.8%. Under similar transesterification conditions, alkali transesterification of esterified fats resulted in the yield of 97.2 wt.% esters. Biodiesel properties were determined and most of the properties were within EN 14214 and ASTM D6751. Biodiesel from animal fats is less stable for oxidation and this is due to the absence of natural antioxidants as compared to the biodiesel of vegetable origin. For this reason, biodiesel produced from animal fats might not be adequate to use at 100% pure in vehicles during cold weather.

KEYWORDS:

• Biodiesel
• pig fat
• free fatty acids
• transesterification
• Esterification

Acknowledgments

This work was financially supported by MICMOD Foundation.

Data availability statement

I declare that all data associated with the manuscript is embedded in the manuscript.