Many scientists predict in the future, Indonesia will be experiencing an energy crisis due to the country’s reliance on only one type of energy source. Petroleum will eventually run out due to its increasing use. Over time, fuel reserves in the earth will become increasingly scarce due to their continuous use. One alternative of renewable fuel is biodiesel. Biodiesel is an alkyl ester compound produced through an alcoholysis process (transesterification) between triglycerides and methanol/ethanol with the help of alkaline catalysts and glycerol. There is also the esterification of (free) fatty acids with methanol or ethanol with the help of alkaline catalysts, transforming into alkyl esters and water. Biodiesel is known as an environmentally friendly and renewable fuel. Biodiesel produced from plant oils or animal fats is usually more expensive than conventional diesel from petroleum. Biodiesel is possible to produce from used vegetable oil, namely used cooking oil. Biodiesel can also be made from seaweed, such as Sargassum sp.
Professor Amin Alamsjah stated,”Sargassum sp. contains sodium alginate (Na-alginate), laminarin, fukoidin, cellulose, mannitol, iron, iodine, vitamin C and minerals such as Ca, K, Mg, Na, Fe, Cu, Zn, S, P, Mn and minerals the other”. “Sargassum also has several advantages, such as relatively short harvesting age, no interfere with the food supply and its cultivation system does not sacrifice food production.”, add professor in seaweed from Faculty of Fisheries and Marine Universitas Airlangga.
This study aimed to produce biodiesel from seaweed and compared it with others biodiesel (commercial, used cooking oil and their combination). The biodiesel efficiency test was conducted on the transesterified oil. The efficiency test of the biodiesel was proven by the flash point, freezing point and viscosity test.
The result of flash point showed that biodiesel made from Sargassum sp. was easy to store because it was not flammable at room temperature. The flash point of biodiesel made from 100% Sargassum was in accordance with the flash point of SNI 04-4182-2006. which had a minimum value of 100°C. Flash point is the lowest temperature where the fuel is still flammable when reacting with air. If the flash occurs continuously at a certain temperature, then it is called the fire point. The higher the flash point of the fuel, then the safer its handling and storage because it is not flammable.
The study of freezing point result showed that Sargassum biodiesel had a very low freezing point; this was in accordance with the SNI-04-7182-2006 standard at a maximum of 0°C. This indicated thatthat biodiesel can be produced and commercialized in high latitude countries due to its very low freezing point. Freezing point is the highest temperature that causes solidification in a liquid substance. The freezing point in biodiesel is an important parameter in several countries. If the commercial fuel has a high freezing point, then the fuel will solidify easily and be unable to flow into the engine.
Unfortunately, the results of viscosity showed that the biodiesel from Sargassum sp. was not in accordance with the viscosity standard of SNI04-7182-2006 at 2.3-6.0 mm2/s. It had the lowest viscosity value of 0.165 mm2/s. However if we combined with 75% of commercial biodiesel, it would produce good viscosity. It met the standard of American biodiesel viscosity (ASTM D6751-12) of 1.9- 6.0 mm2 /s, despite not meeting the SNI standard. Viscosity is a value expressing the amount of resistance of a liquid material to flow or the resistivity of a liquid. Higher viscosity liquids are thicker and more difficult to flow. When injected into the combustion chamber, a low viscosity fuel will be atomized more efficiently, resulting in smaller fuel grains. With these conditions, the process of mixing fuel with air will be more homogeneous so then more fuel is burned. Because more fuel is burned, more energy is released, resulting in an increase in the final combustion pressure.
In conclusion, this study proved that seaweed oil from Sargassum sp. can be used as the materials to produce biodiesel. The use of seaweed for biodiesel has several advantages. Seaweed is highly available, and even abundant at certain times. The greatest abundance of Sargassum sp. usually occurs between June and October with the thallus length reaching 200 cm. In these months, the Sargassum sp. stock is abundant and can pollute the beach. Sargassum sp. biodiesel has high economic efficiency because the raw materials can be found easily in nature and completely unused materials can be utilized.
Author
Muhammad Browijoyo Santanumurti
Faculty of Fisheries and Marine
Email: m-browijoyo@gmail.com
Source
https://iopscience.iop.org/article/10.1088/1755-1315/236/1/012011
