The word “biodiesel” is derived from the Greek word “bio” which means life and “diesel” which is lifted from Rudolf Diesel. According to Ayhan Demirbas (n.d.), “Biodiesel refers to a diesel-equivalent, processed fuel derived from biological sources”. It is specified chemically as monoalkyl esters of long-chain fatty acids. With gas prices skyrocketing and our fossil fuel reservoir slowly dwindling, biodiesel is arguably an extremely viable alternative fuel for trucks and buses.
Biodisel is gleaned from renewable lipids through a process called transesterification. There are various sources of biodiesel.
2.1 Production Technology
Biodiesel is a a chemical compound precipitated via vegetable oils such as soybean and sunflower oil. Biodiesel is also known as methyl esters. These chemical compounds are produced by the reaction between either vegetable oil or animal fat with an alcohol. This reaction is usually catalysed by a potent acid or base, for example, potassium hydroxide or sulphuric acid. The process of making biodiesel is called transesterification. Variables such as fatty acid composition, fatty acid content of oil, type of alcohol, type of catalyst, water content and the rate of stirring will affect transesterification.
2.2 Sources of Biodiesel
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Biodiesel can be manufactured from an array of biolipids such as virgin vegetable oil feedstock, sunflower, hemp and soybean. The common source of biodiesel varies from country to country. In the USA, soybean is the primary source of biodiesel. In Europe, rapeseed is used, while in Malaysia and Indonesia, palm oil is a major biodiesel source. Biodiesel can also be derived from excess vegetable oil, animal fats, non edible oils and algae. Algae as a source of biodiesel is lucrative because it has high yield of biodiesel.
3.0 Advantages of Biodiesel
Biodiesel has many advantages, and it's usage has been gaining in popularity over time due to it's many benefits.
3.1 Made from renewable and easy to obtain oils
Biodiesel is produced from fats and oils such as canola oil, which are easily obtained and are renewable sources.
Biodiesel has been proven to degrade at least four times faster than traditional petroleum diesel. This means that biodiesel is able to be broken down by biological agents.
3.3 Cleaner for the environment
Biodiesel is said to be cleaner and kinder to the environment because not only is it biodegradable, but it is also non-toxic and more or less free of sulphur and aromatics. Therefore, biodiesel usage would result in less putrid odour, which would be a great advantage in confined places and vast urban areas. Biodiesel usage would also cause a reduction of pollutants such as carbon dioxide, therefore it would help to reduce problems like ozone layer depletion and acid rain.
3.4 Reduces hydrocarbon pollution
Regular diesel creates a substantial amount of pollution by the way of hydrocarbons and sulphur emissions. These hydrocarbon causes the ouflow of gases and chemicals into the atmosphere, which contributes to ozone layer depletion. It also alters the pH level of water, so much so that entire fish communities in American freshwater lakes have been eradicated. Besides< that, output of sulphur dioxide and sulphuric acid can also potentially cause detriment to marble and limestone structures. The usage of biodiesel would contribute to the reduction of greenhouse gas components such as carbon monoxide and hazardous diesel particulate in the atmosphere. Biodiesel also has a nicer odour when compared to petroleum diesel.
3.5 Lowers health risks
Biodiesel usage would significantly reduce the health risks that have been associated with conventional petroleum diesel. This is because biodiesel emits less polycyclic aromatic hydrocarbons (PAH) and nitrated polycyclic aromatic hydrocarbons (nPAH), both of which have been distinguished ascompounds that have the potential to cause cancer. Besides that, biodiesel will not cause eye irritation as it is oxygenated, and will undergo more complete combustion than petroleum.
3.6 Offers similar power to diesel fuel
In operation, blends of biodiesel performs much the same as low sulphurdiesel without considerable changes to the engines or fuel systems. This is an advantage as it means that biodiesel can be used in pre-existing engines and fuel injecting equipment without major impact to it's performance.
3.7 Improved lubricity
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The lubricating feature of diesel fuel is important because diesel fuel injection equipment relies on diesel fuel to lubricate it. Fuel with low lubricity may cause it to be worn out easily, while fuel with higher lubricity would potentially result in the equipment being less easily worn out, thus extending the component life.
Currently, biodiesel is more expensive than regular diesel. However, if more biodiesel fuel was used, the cost of it would potentially decrease as more agricultural land could be used to grow crops to be used for making biodiesel.
4.0 Disadvantages of Biodiesel
Although biodiesel usage has many benefits and advantages, it also has some notable disadvantages.
4.1 Technical disadvantages
One technical disadvantage of biodiesel is that it will freeze under conditions which are too cold. Besides that, the energy density will be reduced, and fuel may degrade when stored long-term.
4.2 Enviromental disadvantages
Biodiesel causes higher nitrogen oxide emissions, which could present a problem to the environment as nitrogen oxide is a greenhouse gas that contributes to the enhanced greenhouse effect as well as the thinning of the ozone layer and ultimately, global warming.
4.3 Other disadvantages
Besides technical disadvantages, other disadvantages of biodiesel includes the fact that it has higher viscosity. Other than that, it also has energy content which is lower and higher cloud and pour pointsm as well as injector coking. It may also cause greater engine wear after long-term usage.
In conclusion, the usage of biodiesel brings many significant advantages to us. It is important for us to consider biodiesel as an alternative fuel because we may no longer have petroleum in the future, as the reservoir of fossil fuels is slowly depleting. In such a case, and even before that happens, biodiesel can definitely be considered as a viable alternative fuel to diesel for trucks and buses.