Perpustakaan Digital ITB

Biodiesel is considered as one of the most interesting alternative fuels to address problems of energy security, environmental pollution and also to improve local economic development in Southeast Asian countries. There is considerable potential for ASEAN to produce and supply various biodiesel products to the rest of the world due to its natural resource base; however, the use of biodiesel still presents a number of problems which need to be resolved, especially the high price of raw materials and the quality of biodiesel fuels. In view of these limitations, seeking ways to combine various biodiesel raw materials (e.g. edible and non-edible oils) is one strategy that could be used to solve the problems, reducing the economic cost, utilizing the availability of raw materials and improving the quality of biodiesel fuels particularly cetane number, oxidation stability and cold flow properties. Accordingly, the main objective of this research was to obtain performance, emissions and combustion data of mixed biodiesel fuels by comparison with conventional diesel fuel in order to examine their actual characteristics. Three kinds of mixed biodiesel fuels in form of B10 and B100 together with conventional diesel fuel have been tested in a direct-injection diesel engine. Four biodiesel fuels were mixed to create three biodiesel fuel mixtures in differing weight ratios as follows 70% jatropha curcas oil methyl-ester (JME) with 30% palm oil methylester (PME), (ii) 70% JME with 30% coconut oil methyl-ester (CME) and (iii) 75% soybean oil methyl-ester (SME) with 25% PME. Via analyzing process based on the in-cylinder pressure data and rate of heat release, the obtained results showed that biodiesel fuel mixtures had similar cetane number to diesel fuel (the main factor of this study was to modify cetane numbers of biodiesel fuel mixtures similarly to that of diesel fuel). Moreover, all mixed biodiesel fuels were comparable with conventional diesel fuel in performance, combustion efficiency and significantly reduced exhaust gas emissions (e.g. THC, CO and PM). Especially, the reduction of NOx is an interesting issue in this study; this reduction could be explained by the obtained rate of heat release and the use of antioxidant BHA. The results of this study may provide the basis for promising trend “Blending Strategies” in the biodiesel industry in the near future to find an appropriate cetane number for each kind of diesel engine, reduce the biodiesel cost, utilize the availability of raw materials and improve biodiesel quality with respect to oxidation stability and cloud point.