Production of Biodiesel using Transesterification

Biodiesel production yields varied from 81.7 to 88.0 (wt%), the lowest yields being the ones obtained using waste frying oil and lard alone as raw materials. The obtained products fulfilled most of the determined quality specifications according to European biodiesel quality standard EN 14214. Minimum purity (96.5 wt%) was closely obtained when waste frying oil was used alone and when 0.2% of lard was incorporated in the raw material (96.3 wt%); however, it ranged from 93.9 to 96.3 (wt%) being always close to the limit. From the evaluation of the influence of mixture composition in biodiesel quality, it was possible to establish a model to be used for predicting some parameters of biodiesel resulting from mixtures of waste frying oil with lard when different lard contents are used.
IODIESEL consists of a mixture of fatty acid alkyl esters, that can be used as an alternative fuel in compression-ignition engines; it is obtained from renewable resources, such as vegetable oils and animal fats, which makes it biodegradable and non-toxic [1],[2].
Biodiesel might be produced by transesterification, which is a three-step reversible reaction that converts the initial triglyceride into a mixture of alkyl esters and glycerol, in the presence of a catalyst. Currently, biodiesel production is mainly made using virgin vegetable oils and the major obstacle for biodiesel production is the high price of such raw materials. Additionally, the use of food oils for biodiesel production is controversial; reason why studying alternatives
J. M. Dias is with LEPAE, at the Department of Chemical Engineering
(FEUP), Rua D. Roberto Frias s/n, 4200-465 Porto, Portugal (phone: 00351-
225-081-976; fax: [phone]; e-mail: [e-mail]).
C. A. Ferraz is with LEPAE, at the Department of Chemical Engineering
(FEUP), Rua D. Roberto Frias s/n, 4200-465 Porto, Portugal (e-mail: [e-mail]). M.F. Almeida is with LEPAE, at the Department of