Diesel (fuel) – Characteristics, properties and uses
Gas oil, gas oil or diesel is a hydrocarbon in liquid state that is basically composed of paraffins . It is obtained thanks to the distillation process of crude oil , which is subjected to purification to eliminate sulfur and other components.
It is used as fuel both in heating and in diesel engines . Gas oil or diesel has a lower cost than gasoline , due to a tax issue since its performance is much more efficient.
Diesel fuel or gas oil?
The word diesel is often used to refer to gas oil . This is linked to Rudolf Diesel, who invented the engine that also bears this name. The word association arises because this engine created by Rudolf works especially with diesel, although this fuel is also used in boilers for heating .
- Colour: Whitish or greenish ;
- Density : 850 kg/m3 ;
- Calorific Value: 8,800 kcal/kg .
It is a heavy oil and, like unleaded gasoline , is made from petroleum and other hydrocarbons . Unlike gasoline, diesel oil is not mixed with ethanol, although it does have additives that improve the performance and qualities of the engine. While it is of higher quality, the performance of the engine and its power will also be better, since the diesel will lubricate all its internal components.
Approximately 86.1% of the composition of diesel fuel is carbon. As it is denser than gasoline, it makes the diesel engine more efficient than the Otto cycle . It emits CO2 in a similar or slightly lower concentration than gasoline does.
Diesel or gas oil derived from petroleum is made up of 75% saturated hydrocarbons (isoparaffins and cycloparffins), the rest are aromatic hydrocarbons (alkalobenzenes and naphthalenes).
Its chemical formula is C12H26 , it includes other hydrocarbons with formulas between C10H22 to C15H32 , depending on its purity and purpose.
- The hydrocarbons that make up diesel are very involatile .
- It is characterized by being oily, which allows to lubricate the engine parts.
- The gasoil fraction changes from one place to another according to national standards and the oil used as raw material .
- There are light variants for wagon engines and heavy ones for naval or railway engines.
- The index used to identify or characterize diesel is the cetane number and not the octane rating , as is the case with gasoline. This index determines the flammability and volatility of the fuel.
Types of diesel or diesel
- Gasoil A: It is the one that is commonly allowed for automobiles. There are two varieties: The conventional Diesel and diesel B or Premium Diesel .
- Diesel B: A type of fuel generally used in agricultural and industrial machinery . As it usually has a different tax with respect to conventional diesel, it is known as Bonified Gasoil . It could also be used for heating, although its calorific power is lower than Diesel C. It cannot be used in non-agricultural vehicles, its use is strictly fined.
- Diesel C: Used in domestic heating for hot water and is also for industrial use. It is the diesel with the highest calorific power . It has become as clean and refined as Diesel A or B. It is not recommended for use as fuel, since its formulation has not been designed for engines.
Varieties of Gasoil for diesel engines
Seeking to approach renewable energies for a matter of ecology and environment, variants such as:
- Biodiesel: Diesel can be produced from sources other than petroleum. Biodiesel or B100 is produced based on renewable sources, such as vegetable oils or animal fats. The performance of this biofuel is compared to that derived from oil and the difference is very little.
- Biodiesel blends: Also known as B-20 , it is a mixture of 80% conventional diesel with 20% biodiesel. Another type is the B-5 , where the ratio is 95% regular diesel and 5% biodiesel.
- Ultra Low Sulfur Diesel: This class of fuel has about 20 parts per million of sulfur. This reduces gas emissions such as nitrogen oxide and soot from the engine.
- Regular diesel: It is normal diesel and has turned out to be more polluting than the previous ones, due to the sulfur it contains: about 500 parts per million.
- Diesel grade 1D, 2D and 4D: Diesel is classified in different grades, the most frequent are: 1D, 2D and 4D. This classification corresponds to the densities, with 1D being the least dense of the three. It is often used when the engine speed varies constantly and temperatures are very low. 2D is a fuel grade used in smooth, high-speed, warm-temperature engines. It can be mixed with gasoline to make fuel more effective in winter. 4D is a grade that is not commonly used because it is denser than the others. It is used in motors with very low speed.
Differences between diesel and biodiesel
Diesel and biodiesel are compounds that are used for the same purpose, but their sources are different . Both are used as fuels for diesel engines (trucks, cars, tractors, etc.).
The difference is that diesel is derived from oil ( non-renewable energy source ) and biodiesel is extracted from animals, seeds and vegetable oils ( renewable energy ).
These two compounds also vary in their availability. Diesel is a standard product at most stations, while biodiesel providers are fewer and far between.
Advantages of using diesel as fuel for vehicles
The recommendation between diesel or gasoline engines is usually given once the user’s needs are known; if you are looking for agility and/or speed it will be gasoline, if you are looking for strength or torque it will be diesel. Engines that work with the Otto cycle require gasoline, while diesel engines require gas oil or diesel for their operation.
Diesel as fuel is slightly cheaper than gasoline. Less diesel is consumed than gasoline and is usually more stable. Diesel takes longer to consume , having a positive effect on the pocket. Another advantage of using a car that runs on diesel is that it releases less CO2 into the environment , although the difference is small compared to gasoline.