A Study of Utilization of Coconut Oil for Diesel Fuel

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In order to use coconut oil as a diesel fuel, the manufacturing process, the fuel properties and the diesel combustion characteristics of coconut oil' methyl ester (CME)are investigated. CME is made by alkyl catalyst transesterification with water washing. From the experimental analysis, it is shown that the reaction conditions of transesterification from coconut oil to CME to satisfy the EU standard of bio-diesel are that the ratio of methanol amount to its stoichiometric value is 1.8 to 2.0, the KOH amount is 1% mass to coconut oil, the reaction temperature is 60℃, and the reaction time is one hour. CME has low kinematic viscosity and high volatility compared to RME and PME. The pour point of CME is -5.0℃ and it is not reduced by adding the pour point depressant.The combustion characteristics and exhaust emissions of CME are investigated using a single cylinder direct injection diesel engine, and are compared to PME, RME and JIS No.2 gas oil. The injection timing and ignition delay o … More f CME are almost the same as those of JIS No.2 gas oil. The thermal efficiency of CME is almost the same as the other test fuels. The exhaust emissions (HC, CO, NOx and Smoke) of CME are low compared to the other test fuels due to the higher oxygen content of CME. Especially, at 100% load condition, about 50% reduction in smoke emission is found in CME compare to that of JIS No.2 gas oil. From the practical viewpoint, a blend of 20% CME with 80% JIS No.2 gas oil (CME-B20) is tested. The pour point of CME-B20 is -12.5℃, is same as that of JIS No.2 gas oil. The CO, HC and Smoke emissions of CME-B20 are lower than those of JIS No.2 gas oil.The exhaust emissions and carbon deposit in combustion chamber of diesel engine continuously operated for 50 hours by fuelling CME, CME-B20, RME and JIS No.2 gas oil are investigated. The carbon deposit in combustion chamber after 50 hour run for CME is about 60% higher than that for JIS No.2 gas oil. The carbon deposit of CME-B20 after 50 hour run is slightly lower than that of CME. The acid value of lubricant engine oil after 50 hour run for CME is almost the same as that for the gas oil. It is considered that the carbon deposit of CME must be investigated in detail with the carbon deposit formation mechanism in combustion chamber.From the experimental results, it is concluded that CME is a good alternative fuel as diesel fuel compared PME and RME. Less