Influence of Fatty Acid Methyl Esters in Biodiesel
Biodiesel processed from vegetable oils is the most common biofuel for diesel engines nowadays.The vegetable oils compose of fatty acids and therefore, biodiesel'sphysical and chemical properties,combustion characteristics and exhaust gas emissions are influenced by fatty acids.In this study, in order to examine the influence of fatty acid methyl esters (FAMEs) in biodiesel, five common FAMEs were chosen.Then the total of six forms of FAMEs,two were in straights and four were in blends, were formulated from five FAMEs. These were(i)methyl laurate 100wt% (ML100); (ii) methyl oleate100wt%(MO100); (iii)methyl laurate 50wt%+methyl oleate 50wt% blend (MOL50); (iv) methyl myristate 50wt%+methyl oleate 50wt% blend (MOM50);(v)methyl palmitate 50wt%+methyl oleate 50wt% blend (MOP50); and (vi)methyl stearate 50wt%+methyl oleate 50wt% blend (MOS50). To study their physical and chemical properties, combustion characteristics and exhaust gas emissions,the analyses and engine test experiments were done. Regarding the physical and chemical properties of FAMEs,they were within the reasonable range of a fuel.From the engine test experiments, the ignition delays of FAMEsdecreased with the longer straight chain of hydrocarbon molecules. The brake thermal efficiencies of FAMEswere competitiveand hadgood energy conversion rates.From the exhaust gas emissions, HC and CO emissions from all FAMEsvaried with the oxygen contents.The NOx emissions from FAMEswere seen along with the fuel injection timings of combustion. The smoke emissions of FAMEs were influenced by the oxygen contents and the more oxygen in FAMEs caused the less smoke emissions.
Keywords - Biodiesel, Fatty Acid Methyl Esters, Physical and Chemical Properties, Combustion Characteristics, Exhaust Gas Emissions.