Transesterification of Jatropha curcas linn seed oil using conventional heating method for the production of biodiesel

• Main Authors: Da Cruz, Francisco Jose T., Gong, Shuren C., Veracruz, Rison K.
• Format: text
• Language: English
• Published: Animo Repository 2009
• Subjects: Fossil fuels; Biodiesel fuels; Jatropha; Chemistry, Organic; Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/7775
• Institution: De La Salle University

There is an increasing problem of depletion of fossil fuels. Most of our modern technologies require burning of fossil fuels. The fuels are used either directly (vehicle fuels) or indirectly (to produce electricity to power our appliances). Moreover, this non-renewable source of fuel has a major effect on our climate. One of the solutions to these problems is to use biodiesel, which is a renewable fuel source. Biodiesel is a good alternative to conventional diesel because it has much fewer emissions when it burned and is safer to handle. For the oil to undergo a base-catalyzed process, transesterification, it should have a small amount of free fatty acid (FFA) in it. The acid value and free fatty acid content of the crude Jatropha oil were calculated to be 12.7mg KOH/g oil and 6.4% respectively. This is too high for the oil to undergo transesterification. The oil underwent acid pretreatment, also known as esterification, before transesterification. The esterification of the crude Jatropha oil was conducted using 12% (w/w) methanol as the alcohol and 1% (w/w) hydrocholoric acid as the catalyst, and was reacted for two hours at a temperature of 70ºC. The resulting oil had an acid value of 1.5 mg KOH/g oil and 0.70% free fatty acid content after esterification, which is enough for the esterified oil to proceed to the transesterification process. The transesterification process was conducted using the parameters: methanol as the alcohol with the molar ratios of alcohol to oil of 4:1 and 6:1, reaction times of one and two hours, temperatures of 45ºC and 60ºC and 0.5% and 1.5% (w/w) of NaOH and KOH as the catalysts. The combination of parameters that gave the highest yield of biodiesel at 92.31% were: a reaction time of two hours, a methanol to oil molar ratio of 4:1, 1.5% (w/w) of KOH as the catalyst, and a reaction temperature of 60ºC. The density of the biodiesel was found to be between 0.8600 and 0.8942 g/ml and the kinematic viscosity was found to be 4.1 cSt, both of which complies with the standards listed in the Philippine National Standards for Biodiesel (PNS). The flash point of the biodiesel samples fell between 169ºC and 179ºC. The cloud point of the samples had an average of 6ºC. The acid values of the biodiesel samples were so small that it is negligible.