EFFECT OF POLYUNSATURATED FATTY ACIDS REMOVAL ON BIODIESEL OXIDATION STABILITY
Biodiesel as a biofuel that has been developed in the past 20 years has now become a popular substitute for fossil diesel fuel. Compared to fossil diesel fuel, biodiesel is better in various aspects such as emissions, toxicity, biodegradability, engine lubrication and impact on national energy secur...
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| Format: | Theses |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/55217 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Biodiesel as a biofuel that has been developed in the past 20 years has now become a popular substitute for fossil diesel fuel. Compared to fossil diesel fuel, biodiesel is better in various aspects such as emissions, toxicity, biodegradability, engine lubrication and impact on national energy security. Although palm oil biodiesel has excellent quality, its oxidative stability is still far lower than fossil diesel fuel. This is because palm oil biodiesel contains a relatively small amount (9-12 %) polyunsaturated fatty acids, which has very bad effect on oxidation stability. To improve it, these polyunsaturated fatty acids methyl ester should be removed from the biodiesel and one way to do it is through liquid-liquid extraction using silver nitrate (AgNO3) solution and adsorption with silver acetate (AgCH3COO).
The extraction process was carried out by varying the concentration of AgNO3 (1 M and 5 M), the concentration of methanol solvent in the solution (10%-v, 25%-v, and 50%-v), and the ratio of biodiesel to AgNO3 (1 : 1 and 1 : 2) at 25-35°C for 3 hours and followed by separation of the extract and raffinate for 45 minutes. On the other hand, the adsorption process was carried out at temperature 25-30°C for 15 minutes followed by the separation of AgCH3COO from biodiesel through filtration.
According to this research, induction period for all variation decreased compare to biodiesel before extraction. However, the GC-MS and iodine number analysis showed a reduction in polyunsaturated fatty acids methyl ester after extraction. The best result for extraction method were shown by sample 1 M, 10%-v methanol, 1: 1 with rancimat induction period 15.26 hours, polyunsaturated fatty acids methyl ester compositions 0.08%, and iodine value 49.755 g iod/100g. For the adsorption process, the best result was shown by sample with biodiesel volume 30 ml without nitrogen injection with rancimat induction period 10.64 hours, polyunsaturated fatty acids methyl ester compositions 0%, and iodine number 39.703 g iod/100g. |
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