Biodiesel is a biofuel obtained from renewable sources such as vegetable oils or animal fats. Let’s see its characteristics.
Biodiesel, despite what is commonly believed, is not a pure and simple vegetable oil (such as rapeseed oil). Instead, it is the result of a chemical process: that is, the transesterification of vegetable oil with ethyl alcohol or methyl alcohol. This fuel is liquid , amber in color and transparent.
What is biodiesel
Biodiesel is a fuel made entirely from vegetable oil, such as rapeseed or sunflower or other types. The viscosity of this fuel is very similar to that of gas oil which is obtained from the fractional distillation of crude oil. As regards the identification of blends, biodiesel is identified with the initials BD, while for bioalcohol the initials BA is used.
Sometimes biodiesel is assigned the abbreviation BD100. The blends will instead be identified with an abbreviation to which a number will be added that refers to the percentage of biodiesel contained: for example, the abbreviation BD20 will be used, for a diesel cut with a percentage of biodiesel at 20 percent.
How it is produced
In the production of biodiesel, the specifications determine and fix some important points, with regards to the production processes . These important points are:
- the completeness of the chemical reaction;
- the removal of glycerol;
- removal of catalyst and alcohols
- the absence of free fatty acids.
If there is full compliance with these particular characteristics, verified by gas chromatography, we can speak of biodiesel. The fuel obtained following these production phases will be absolutely not very toxic.
Bioediesel can be safely combined and mixed with diesel in any type of percentage and used in modern diesel engines : however some vehicles characterized by an older production could, following the combustion of biodiesel, suffer a degradation of the pipes and joints in eraser. Cars produced after 1992 should theoretically not have this type of problem.
Since biodiesel is mainly used as a blended fuel with petroleum diesel, there is not much information and many studies related to the effect of pure biodiesel on automotive engines. However, the opinions of the engineers agree on one fact: there should be no particular problems of using pure biodiesel.
Biodiesel has a higher quantity of cetane than the quantity present in diesel: this makes biodiesel easier to ignite , once it has been injected into the engines. However, unlike petroleum diesel , it is not explosive . Furthermore, unlike diesel, it is biodegradable, non-toxic and significantly reduces toxic emissions when it is burned as a fuel.
One of the main advantages of using biodiesel as a fuel is its minimal environmental impact , when compared to diesel. In fact, compared to diesel, it reduces net carbon monoxide emissions by 50 percent. There is also a 78.4 percent reduction in carbon dioxide.
The carbon that is emitted in the combustion phases is simply that already normally present in the atmosphere: the plant has fixed it during its growth. Unlike the emissions of diesel fuel, whose carbon had previously been trapped in the earth’s crust. However, the energy costs in the phases of cultivation of the raw material for obtaining biodiesel will certainly be considered. The energy costs of processing and transporting biodiesel will also be considered.
Another important and significant advantage of this fuel is that it practically does not contain aromatic hydrocarbons whose emissions in condensed rings, such as benzopyrenes, are in fact reduced by 71 percent. Biodiesel is also not characterized by sulfur dioxide emissions, since it does not contain sulfur at all.
As a last advantage, the reduction of fine dust emissions reduced by up to 65 percent will be considered. The biofuel sector has continued to grow significantly in recent years. For this reason, many interests derive from it, which are increasingly at the center of international geopolitical agreements. However, in recent years, internationally there is a lot of discussion about the problem, of agro-energy monocultures on biodiversity.
Undoubtedly, the use of biodiesel as a fuel also has disadvantages. This substance certainly produces more nitrogen oxide emissions , when compared to diesel emissions. This emissions disadvantage of biodiesel can be remedied by redesigning diesel engines.
Particular catalysts can be added to the exhausts. The use of biodiesel as a fuel certainly has negative socio-environmental consequences. First of all, the land is subtracted from the cultivation of food for humans, in favor of crops for fuel to power the machines.
There could also be an increase in the cost of raw materials , especially in Third World countries (problem of food insecurity). If monoculture biodiesel cultivation techniques were implemented, this would inevitably lead to a reduction in biodiversity: consequently the erosion of the subsoil would increase and the risk of crop destruction by insects and bacteria would increase .
There has been much discussion in recent years about other local food productions. Certainly there is a high risk for developing or defined Third World countries. In the event of an uncontrolled growth of biofuel crops, a large deficit in local food production could occur . This following an inevitable exodus of local food producers.
For these reasons, many economists believe that the spread of biofuel production can have a decidedly negative influence on the phenomenon of hunger in the world. In fact, the subtraction of land that today is used for the cultivation of cereals would be too high. Today they constitute the main nourishment of the populations who live in poor countries. These countries base their economy mainly on the primary sector. It should be considered that the FAO price index for basic foodstuffs reached its all-time high in 2010. For this reason, many revolts broke out in North Africa in 2011.