Soybean Oil De-Acidification as a First Step Towards Biodiesel Production

Abstract

According to the predictive studies of the World Energy Outlook 2009, the global demand of energy is expected to increase till 2030 of about 1.5 percentage points per year. Fossil fuels are expected to remain the main energy source in the world, but in the meantime renewable energy sources (wind, solar, geothermal, bioenergy) will be characterized by a rapid growing rate. Their use and development is strongly encouraged by most of the recent regulations. For instance, as reported by the European Environment Agency Transport (EEA), 2009, the European Union required in the same year to achieve by 2020 at least 10% of mixture of hydrocarbons from renewable and conventional sources for what concerns the energy employed for the transports. In addition, the increase in oil price and the growing interest in environmental issues have recently given a considerable impetus to the research for cleaner and renewable energy sources, in order to ensure a sustainable future. Biodiesel (BD) is a renewable energy source in liquid form that has many advantages over normal diesel, including lower emissions of gases harmful to humans and environment. The UE directive 2003/30/EC, defines the Biodiesel as “a methyl ester produced from vegetable or animal oil, of diesel quality, to be used as biofuel”. Moreover, the National Biodiesel Board (NBB), 1996, responsable for biodiesel ASTM standards, define biodiesel as “the mono alkyl esters of long chain fatty acids derived from renewable lipid feedstock’s, such as vegetable oils or animal fats, for use in compression ignition (diesel) engines.” The processes for BD production are well known. According to the NBB, 2007, there are three main routes to BD production from oils and fats: Basecatalyzed transesterification; Direct acidcatalyzed transesterification; Conversion of the oil into fatty acids and then into biodiesel. At the present BD is mainly produced through the base-catalyzed transesterification for many different reasons: Mild reaction conditions, i.e. low temperature and pressure may be adopted; High conversions (up to 98.5%) are usually achieved in short times with minimization of side reactions; The conversion into BD is direct and no intermediate steps are required;