Biodiesel Production from High Acidity Raw Materials: Acid and Base Catalysis Combination

B. DALLA COSTA; M.L. PISARELLO; S.N. PATO; C.A. QUERINI

Philadelphia - USA

Congreso; 19th North American Meeting on Catalysis.ACS; 2005

The biodiesel is a renewable fuel obtained by a transesterification reaction between a vegetable oil or an animal fat with an alcohol, such as methanol or ethanol, in the presence of a suitable catalyst such as sodium hydroxide. It has many important advantages as compared to the petroleum diesel or gas oil. Among the most important are the CO2 closed cycle, and the negligible emission of sulfided compounds. One of the distinctive features of the biodiesel, is its very good lubricity, which makes it a very suitable candidate to be used both to decrease the sulfur level, and to increase the lubricity of the fuel. Because of these and other environmental reasons, it is a fuel of increasing use across the world. The use of traditional raw materials, such as oils from soybean , rapeseed, sunflower, corn, etc, leads to the production of a fuel with higher prices than the diesel that is obtain from the petroleum industry. Nevertheless, environmental and strategic reasons, had given to this fuel increasing importance in many countries. Additionally, there are options for biodiesel production with competitive costs, such as small-scale production units to produce the biodiesel from alternative raw materials. These materials with lower economical value, are for example recycled frying oil, acid tallow, and brown greases with very high acidity. In our laboratories, we developed methodologies to use these type of raw materials for biodiesel production. This requires the design of a two-step process, combining acid and base catalysis. In this work, we present results regarding the methodology followed to obtain biodiesel from low-value raw materials, with high acidity values, and therefore not suitable in order to be used in the traditional base-catalysed process. Detailed physicochemical characterization of the system was also addressed.