Possibility of using tannery waste for biodiesel production

Abstract

Waste fat produced by tanneries during the processes in which raw hide is transformed into leather represents a very important raw material for biodiesel production. Under laboratory and pilot-scale conditions, biodiesel samples were prepared from waste tannery fat and required analyses were carried out. The process of biodiesel production has three stages: 1) refining melting of the raw material (separation of fats from other undesirable components), 2) organic base-catalyzed methanolysis and 3) separation of glycerin layer. The mathematical model of zonal refining melting is presented in this paper as well as the results of the refining and methanolysis product analyses. The use of organic bases (tetramethylammonium hydroxide, n-butylamine, cyclohexylamine, etc.) is innovative. It enables us, in addition to considerable financial benefits, to produce a high quality biodiesel and glycerin containing practically no ash. Further, it contains a residual amine that works as a stabilizer, and after methanolysis the amine can be partially recycled.