The concept of using vegetable as fuel dates back to 1985 when Dr Rudolf Diesel developed the first diesel engine to run on vegetable oil. He demonstrated his engine at the world exhibition in Paris in 1900 and described an experiment using peanut oil as fuel in his engine. However, transesterification of vegetable oil was conducted as early as 1853 by scientists E. Duffy and J. Patrick, many years before the first diesel engine became functional.
Chemically, transesterified biodiesel comprises a mix of mono-alkyl esters of long chain fatty acids. The most common form uses methanol to produce methyl esters as it is the cheapest alcohol available. Ethanol can also be used to produce an ethyl ester biodiesel. The use of higher molecular weight alcohol such as isopropanol and butanol will improve the cold flow properties of the resulting ester but is less efficient during the transesterification reaction. Glycerol is an inevitable byproduct of this reaction.
A variety of oil can be used to produce biodiesel such as palm oil, soyabean oil, sunflower oil, algae oil, waste vegetable oil and animal fats. In addition, the thermal depolymerization process can also be used to produce biodiesel. This process can reduce almost any hydrocarbon based feedstock, including non oil based feedstock, into light crude oil.
However, the latest technology to produce biodiesel uses ultrasound technology or ultrasonic transesterification to produce biodiesel from oil. This ultrasonication can achieve a biodiesel yield in excess of 99%. Ultrasound reduces the processing time from the conventional 1 to 5 hour processing batch to less than 5 minutes. Ultrasonication can also help to reduce the separation time from 5 to 10 hours. Moreover, the international standards for biodisel ensures that important factors such as complete reaction, the removal of glycerin, the removal of a catalyst, the removal of alcohol, the absence of free fatty acid and low sulfur content are adhered to.
Blends of 20 percent biodiesel with 80 percent petroleum diesel (B20) can generally be used in unmodified diesel engines. Biodiesel can also be used in its pure form (B100), but may require certain engine modifications to avoid maintenance and performance problems.
Major issues, with regard to the mass production of biodeisel cousers the environment. Most develop countries will cut large areas of tropical forest in order to grow palm oil for biodisel. For example, in the Philippines and Indonesia, both countries plan to increase their biodiesel production level significantly, which will lead to the deforestation of tens of millions of acres and the loss of numerous species of plants and animals. The usage of pesticides will triple.
According to a study written by Drs. Van Dyne and Raymer for the Tennessee Valley Authority, the average US farm consumes fuel at the rate of 82 liters per hectare (L/ha) (8.75 US gallons per acre) of land to produce one crop. However, average crops of rapeseed produce oil at an average rate of 1,029 L/ha (110 US gal/acre), and high-yield rapeseed fields produce about 1,356 L/ha (145 US gal/acre).
Alternatively, a recent paper from Michael Briggs(1996), “Aquatic Species Program” discuss using algae as a source of biodiesel because it has a natural oil content greater than 50%. Briggs also suggests that algae can be grown on ponds at wastewater treatment plants. This oil-rich algae can then be extracted and processed into biodiesel comparison, palm oil can produce 5950 litre oil/ha, while algae can produce 95,000 litre oil/ha. Comparatively speaking, only 28,000 km² or 0.3% of the land area of the US would be utilized to produce enough biodiesel to replace all transportation fuel the country currently utilizes.
On May 11, 2006 the Aquaflow Bionomic Corporation in Marlborough, New Zealand announced that it had produced its first sample of bio-diesel fuel made from algae found in sewage ponds. Unlike previous attempts, the algae was naturally grown in pond discharge from the Marlborough District Council’s sewage treatment works.
In conclusion, Biodiesel is attracting of interest in commercial scale production in Malaysia Additional factors must be taken into account, such as; the fuel equivalent of the energy required for processing, the yield of fuel from raw oil, the return on cultivating food, and the relative cost of biodiesel versus petrodiesel.
However, using plants to feed our fuel needs, may be a great idea but people may go hungry as food prices rise if farmers sense higher profits in fuel crops than in growing plants to feed people.