|Fuel from the Wok|
Declining energy sources forces us to find new solutions. Siti Kartina Abdul Karim sees that biodiesel from plant oil can be in place of fossil fuels as it has similar characteristics to fossil fuels. The testing done by Malaysian Palm Oil Board shows that Malaysian palm oil biodiesel has achieved the standards set by the European Standards for Biodiesel (EN 14214) and American Standards Specifications for Biodiesel Fuel (ASTM D6751). Therefore, the oil palm may be able to reduce dependency on fossil fuels.
Palm oil can be changed to biofuel in several manners. The simplest and most widely used is transesterification. If not changed to fuel, the crude palm oil (CPO) and waste cooking oil (WCO) are only to be turned to feedstock.
In this test, three samples of WCO and one of CPO were used for transesterification. The sources of WCO were the KKUiTM cafe, the McDonalds restaurant (Section 2, Shah Alam) and a fried banana stall (Section 2, Shah Alam). The chemicals used were potassium hydroxide (KOH), magnesium sulphate heptahydrate (MgSO4.7H2O) and methanol. Then the two yields of biodiesel and methyl esters were compared.
The results showed that the yield from the CPO (97 wt%) was very similar with that of all WCO samples, which was in the range of 93-98 wt%. However, the methyl ester compositions of biodiesel from CPO produced a higher value of C16 and C18 compared to that of the WCO samples.
The yield of biodiesel from CPO in this experiment was about 97%. In comparison, the sunflower oil shows similar results using very similar experimental conditions. Nevertheless, the yields of the crude oil were found to be in the range of 70 to 90%, for crude oils with acid value of 1 to 6%. Generally, the higher acid value of around 6%, found in crude peanut oil, greatly reduces the ester yield to only 70%. This is partly due to the presence of impurities in crude oils. Thus the authors proposed using refined or crude oils that contain lower acidity for another result.
The yield trend for the WCO relies greatly on the amount of moisture and the free fatty acid (FFA) contents. A good feedstock for an alkali-catalysed transesterification should only contain less than 0.5% of water. This study illustrated that the ester yields were reduced with the increasing amount of water and FFA contents. In this case, the water content favours saponification reaction, and the soap produced, prevented glycerol separation and therefore reduced the ester yield. Preheating prior to transesterification and removing water content after transesterification might be the reason of higher biodiesel yield.
Siti Kartina said that further research on the physical properties of this type of biodiesel, its cost implication of the feedstock and alternative feedstocks are needed for industrial purposes.