(303b) Super Critical Transesterification of Fats and Lipids Extracted from Dissolved Air Floatation Sludge

In recent years, biodiesel has gained immense attention as an alternative to diesel due to rise in petroleum prices, environmental concerns and energy security. The high cost of biodiesel is majorly due to the high cost of feedstocks which are generally edible oils and are not economically feasible. These challenges can be solved by utilizing unconventional sources of oils like non- edible oils and waste cooking oils for biodiesel production.

We examine the potential of using dissolved air floatation (DAF) sludge obtained from local rendered meat processing plants and municipal wastes sludge as a feasible feedstock for biodiesel production using non-catalytic methods. Alkali catalysts method of transesterification of oils involve various shortcomings in the form of high water and free fatty acid (FFAs) content which leads to unwanted side products and saponification leading to low biodiesel yield. Using a less efficient acid catalyst removes this problem but reaction times are unfavorable and requires reaction times of up to 48 hours. This problem becomes more pronounced for lipid sources based on rendered meat industry by products which are rich in FFAs and water. Super critical transesterification is a very effective technique to bypass these shortcomings and provides high yield of biodiesel. DAF sludge was characterized and chemical composition and lipid composition was assessed. Subsequently, extracted lipids were transesterified in a lab scale supercritical reactor set up and various factors like methanol to oil ratio, temperature and reaction time were investigated.