Glycerin Revalorization Using Anaerobic Digestion of Organic Waste

Abstract

A novel process for the revalorization of glycerine from biodiesel production is proposed. Glycerol is converted to short chain oils by reaction with volatile fatty acids. The volatile fatty acids can be obtained from anaerobic digestion of organic waste streams. It is shown that there is a minimum viscosity according to the oil chain length. Therefore the obtained short chain oils present viscosity values that make them useful as biodiesel additives increasing its lubricant properties. Listing some experimental results from literature, the process requirements are determined providing a maximum reaction rate to the desired volatile fatty acids, i.e. high substrate content and low acid content. A novel process satisfying these requirements with a low energy demand is provided. A frying potatoes factory is used as illustrative example.