High quality biodiesel and glycerin from fleshings

Abstract

Animal fleshings represent more than 50% of the total waste generated by the leather industry. Generally, the fleshings represent undesirable waste the elimination of which is often connected with expenses. However, this waste contains valuable protein and fat fractions. For this reason, a complex procedure for separation and utilization of both fractions was suggested. The method involves sodium chloride removal with subsequent protein and fat separation. The proposed desalting operation facilitated significant reduction of ash content and consequently the obtained protein fraction has acceptable properties for commercial application. A mathematical model of this process was worked out. The model enables to find the optimal conditions at which the practical desalting should be carried out. The obtained fat is deacidified and the resulting quality product is suitable for direct biodiesel production. The analyses of the prepared biodiesel confirmed high conversion of transesterification reaction and thus optimal purity of the feedstock. Even the sulfur content which could be an issue in fleshings utilization for biodiesel production was low enough to meet the biodiesel standard of quality EN 14 214.