What is biodiesel

Qué es el biodiesel

Biodiesel is a liquid synthetic biofuel that is obtained from natural lipids such as vegetable oils or animal fats. The product manufactured industrially by esterification and transesterification processes, is applied in the preparation of total or partial substitutes for petrodiesel or gas oil obtained from petroleum. As a total substitute, it is called B100, while other names such as B5 or B30 refer to the proportion or % of biodiesel used in the mixture. Biodiesel, whose properties have been known since the mid-19th century, is intended for combustion in conventional or adapted diesel cycle engines, according to the manufacturer, and for this reason, at the beginning of the 21st century, its development as an alternative fuel for automobiles to derivatives was promoted. of the oil. The environmental impact and social consequences of its foreseeable mass production and commercialization, especially in developing or Third World countries, is the subject of debate among specialists and different international social and governmental agents.
Biodiesel is not a novelty of recent years, much less a discovery of the last decades, since the first

er motor diesel del mundo, utilizado en el 1903 en suiza, por el señor Rudolf Diesel, utilizo aceite de maní como combustible.

Physicochemical properties

Biodiesel is chemically described as organic compounds of monoalkyl esters of long-chain fatty acids.

Synthesis reactions

The transesterification process consists of combining the oil (usually vegetable oil) with a light alcohol, usually methanol, leaving glycerin as a value-added residue that can be used by the cosmetics industry, among others.

Raw Materials

The source of vegetable oil is usually rapeseed oil, as it is a species with a high oil content, which adapts well to cold climates. However, there are other varieties with higher yields per hectare, such as palm, jatropha curcas, etc. Used oils (for example, frying oils) can also be used, in which case the raw material is very cheap and, in addition, what would otherwise be waste is recycled. However, the alcohol that is formed remains at 95% purity, this being something very bad for the engine since it is promoting impurity.

Advantages and disadvantages


  • Biodiesel significantly reduces the main emissions from vehicles, such as carbon monoxide and volatile hydrocarbons, in the case of gasoline engines, and particles, in the case of diesel engines.
  • Biodiesel production is an alternative land use that avoids erosion and desertification phenomena to which those agricultural lands that, for market reasons, are being abandoned by farmers may be exposed.
  • Biodiesel represents a saving of between 25% and 80% of CO2 emissions produced by fuels derived from petroleum, thus constituting an important element to reduce greenhouse gases produced by transport.
  • Due to its higher cetane number(1) and lubricity, it reduces wear on the injection pump and nozzles.
  • It does not have sulfur compounds, so it does not eliminate them as combustion gases.
  • Biodiesel is also used as an oil alternative for two-stroke engines, in various percentages; the most used percentage is 10/1.
  • Biodiesel can also be used as an additive for gasoline engines (naphtha) for internal cleaning of these. 

(1) The cetane number, similar to the octane number in gasoline, is the measure that diesel has as an antiknock. This is indicative of the energy efficiency of the reaction that takes place in internal combustion engines.
This cetane number corresponds to the amount (volume percentage) of cetane (hexadecane) present in a reference mixture with the same flash point as the fuel (hydrocarbon) under test.
The cetane number is higher the shorter the ignition index


The exploitation of oil palm plantations (used to make biodiesel) was responsible for 87% of Malaysia's deforestation until the year 2000. In Sumatra and Borneo, millions of hectares of forest were converted to cultivation land for these palm trees and in recent years more than double that figure has been achieved, logging and fires continue. They even completely deforested Kalimantan's famous Tanjung Puting National Park. Orangutans, gibbons, rhinos, tiger tapirs, clouded leopards, etc… will become extinct due to habitat destruction. Thousands of indigenous people have been evicted from their lands 1500 Indonesians were tortured. But governments, as long as Europe continues to buy their oil palm to make biodiesel, will continue to promote the cultivation of these plants for their own benefit.

Despite its many advantages, it also presents some problems. One of them is derived from its better solvent capacity than petrodiesel, which is why the existing residues are dissolved and sent through the fuel line, which can clog the filters. Another item is a lower energy capacity, approximately 5% less, although this, in practice, is not so noticeable since it is compensated by the higher cetane index, which produces more complete combustion with less compression.

There is no record of them producing larger combustion deposits or degrading cold start of engines.

Other problems that it presents refer to the area of storage logistics, since it is a hydrophilic and degradable product, for which an exact planning of its production and expedition is necessary. The product degrades significantly faster than petrodiesel.

Until now, the useful life of biodiesel is still not clear; some say that it has a very short life time (months) and others that its useful life is even 10 years or more. But all agree that it depends on its handling and storage.

The average yield for oilseeds such as sunflower, peanuts, rice, cotton, soybeans or castor beans is around 900 liters of biodiesel per hectare harvested. This can make it impractical for countries with little arable land; however, the great variety of seeds suitable for its production, many of them complementary in their rotation or with by-products that can be used in other industries, makes it a sustainable project. However, jatropha is beginning to be used to produce vegetable oil and, later, biodiesel, and it can be grown even in desert areas.

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