Biodiesel Fuels from Vegetable Oils Transesterification of Cynara cardunculus L. Oils with Ethanol

Biodiesel Fuels - Energy Fuels 2002 16 443-450 443 Biodiesel Fuels from Vegetable Oils Transesterification of Cynara cardunculus L Oils with

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Biodiesel Fuels from Vegetable Oils: Transesterification of Cynara cardunculus L. Oils with Ethanol J. M. Encinar,* J. F. Gonza ´lez, J. J. Rodrı´guez, and A. Tejedor Departamento de Ingenierı ´ a Quı ´ mica y Energe ´ tica, Universidad de Extremadura, Avda. de Elvas s/n, 06071 Badajoz, Spain Received July 17, 2001. Revised Manuscript Received November 9, 2001 A study was made of the transesterification reaction of Cynara cardunculus L. oil by means of ethanol, using sodium hydroxide and potassium hydroxide as catalysts. The objective of the work was to characterize the ethyl esters for use as biodiesels in compression ignition motors. The operation variables employed were temperature (25 - 75 °C), catalyst type (sodium hydroxide and potassium hydroxide), catalyst concentration (0.25 - 1.5 wt %), and ethanol/oil molar ratio (3:1 - 15:1). Oil mass (200 g), reaction time (120 min), and alcohol type (ethanol) were fixed as common parameters in all the experiments. The evolution of the process was followed by gas chromatog- raphy, determining the concentration of the ethyl esters at different reaction times. The biodiesel was characterized by determining its density, viscosity, high heating value, cetane index, cloud and pour points, characteristics of distillation, and flash and combustion points according to ISO norms. The biodiesel with the best properties was obtained using an ethanol/oil molar ratio of 12:1, sodium hydroxide as catalyst (1%) and 75 °C temperature. This biodiesel has very similar properties to those of no. 2 diesel fuel. Introduction Diesel fuels have an essential function in the indus- trial economy of a country. They are used in city buses, locomotives, electric generators, etc. The diesel fuel consumption of developed countries has been increasing steadily over the last few decades and looks set to continue into the future. An alternative diesel fuel must be technically feasible, economically competitive, envi- ronmentally acceptable, and readily available. 1 Given these requirements, triglycerides (vegetable oils/animal fats) and their derivatives may be considered as viable alternatives for diesel fuel. 2 - 5 Vegetable oils are widely available from a variety of sources, and they are renewable. Also, these fuels are easily biodegradable, they have a practically null sulfur content, and their transport and storage offer no problems. Moreover, vegetable oils sequester more carbon dioxide from the atmosphere during their production than they add to it when they are burned. Therefore, they help to alleviate the increasing carbon dioxide content of the atmosphere. Their main drawback is price, which is higher than petroleum-derived diesels. In consequence, their use must be accompanied by a policy oriented toward their total tax exemption. The heating value of vegetable oils is similar to that of fossil diesel, but their use in direct injection diesel engines is limited by some of their physical properties, especially their viscosity. Vegetable oil viscosity is 10 times greater than that of diesel oil, with consequent
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This note was uploaded on 10/21/2010 for the course S a taught by Professor S during the Spring '10 term at Glasgow Caledonian University.

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Biodiesel Fuels - Energy Fuels 2002 16 443-450 443 Biodiesel Fuels from Vegetable Oils Transesterification of Cynara cardunculus L Oils with

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