Optimised Production of Biodiesel Synthesised from Waste Animal Fat

The fleshings produced during the pre-tanning process in tanneries and animal wastes generated from slaughter house are causing serious environmental concern because of improper disposal techniques. These solid wastes contain fat and proteins which can be recovered for wide variety of applications. The fats extracted from these wastes are used as feedstock for the production of biodiesel, which serves as an alternate for conventional diesel fuel because of their sustainability. The use of these animal fats ruled out the issues over the ‘Food versus Fuel’ conflict, as edible feed stocks were used in the production of biodiesel earlier. This work projects on the synthesis of biodiesel from waste animal fats by the means of methyl-based transesterification. A maximum fat recovery of 85% was achieved by the means of autoclave heat treatment method. The refining of fat was carried out by following acid degumming, where Orthophosphoric acid was mixed with the fat to remove the phospholipids as residues. Pretreatment of the extracted fat was done using glycerolysis, where the FFA % of these fats were reduced from 7% to 0.25% with a recorded efficiency of 96.4%. Alkali catalysed transesterification was carried out by investigating various operating parameters like oil/alcohol molar ratio, catalyst concentration, temperature and reaction time and optimising them. The optimised process parameters produced a maximum yield of 94% biodiesel. The fuel properties of the produced biodiesel were compared with the ordinary diesel fuel based on both ASTM D-6751 and IS 15607: 2005 standards.