EVALUATION AND CHARACTERIZATION OF FATS AND RESIDUAL COOKING OILS FOR THE PRODUCTION OF BIODIESEL: A CASE STUDY

The waste cooking oils and fats (WCOF) from the catering industry were systematically evaluated in Tuxtla Gutierrez, Chiapas. Results pointed out that the eight restaurant types found in the city produced 174 t of WCOF/year in the following proportion: 41 % formal restaurant, 24 % fast food, 8 % taquerias, 7 % antojitos, 6 % soup kitchens, 6 % bars, 4 % gorditas and 4 % roast chicken shops. In addition, representative samples of WCOF coming from every restaurant type were characterized for biodiesel production, in terms of viscosity, oxidative stability, free fatty acid content, acid value, saponification number, moisture content and fatty acid composition. The physicochemical analysis suggests that all the WCOF produced in the city, except that coming from the fast food cooking, met the recommended free fatty acid levels and the acidity values for alkaline transesterification. Based on the population of the city an average production of 0.31 t/year of WCOF per 1000 inhabitants was estimated. Projecting this figure to the whole country of Mexico, 34.9 kt of this fuel would be obtained per year, which would avoid the emission of 92 kt/year of CO2 and contribute to reduce pollution in the country.