Diesel fuel, diesel oil (Gasoil) is a liquid fuel specifically designed for use in diesel engines such as light and heavy vehicles, generators, boats and ships, industries and power plants, pleasure boats and rail transport. Diesel is obtained from the middle height of the atmospheric distillation tower of the refinery in one phase (200 to 350 degrees Celsius) by cooling the oil in several stages, and after processing and reducing disturbing elements and mixing with a small percentage of kerosene (up to 5%). And the modification of some specifications, such as flash point and boiling point, to standard indicators, is launched on the market.
The characteristics of diesel differ according to its applications in diesel engines and the origin of the primary crude oil from which it is obtained. One of the important characteristics of diesel is its density, which has a relatively higher weight than other common fuels. The density of diesel is usually in the range of 0.8 kg/liter to 0.87 kg/liter. The higher the amount of hydrocarbons and aromatics in diesel, the higher its density. Another thing that defines the characteristics of diesel is distillation. The starting point of diesel distillation is at a temperature of about 180 degrees Celsius and the end point of its distillation is at a temperature of about 370 degrees Celsius. This characteristic is obtained through the ASTM standard, which is the distillation percentage of diesel at different temperatures as follows:
– Less than 65% at 250°C
– More than 85% at 350°C
– More than 95% at 370°C
The yellow color of diesel is only due to the presence of sulfur; Euro 6, Euro 5, Euro 4 diesels are colorless white and have 0/50/10 ppm sulfur respectively.
Its average chemical formula is considered to be C12H23 and its hydrocarbon range is between C14-C20 and even C25 with a boiling point range of 150-385 degrees Celsius.
Gas oil mainly consists of three paraffinic, naphthenic and aromatic groups, has a minimum flash point of 54°C and a maximum pour point of 0°C. The most important characteristic of diesel is the number of cylinders, which must be more than 50 for the engine to work smoothly and quietly. The amount of cetane depends on the process from which diesel is produced. The higher this number, the better the quality of diesel combustion. Gasoil is a broad term that can refer to a range of intermediates and final petroleum products in the range of diesel or VGO.
Intermediates sometimes referred to as diesel include:
Light Atmospheric Gasoline (LAGO) – direct material in the diesel range from the atmospheric distillation tower Heavy Atmospheric Gasoline (HAGO) – Direct material between diesel and VGO range from atmospheric distillation tower Vacuum Gasoline (VGO) – the lighter residue fraction from the vacuum distillation tower Diesel coker – VGO range product of hydrocracked diesel coker
Diesel Fuel Class No. 1 products have fewer energy components and are more expensive than their basic counterpart, Class 2 products. Due to the absence of paraffin in the chemical mixture D1, it remains in liquid form during the winter months, and it rarely causes problems in cold weather conditions compared to grade 2 products. Fuel number 1 has the following disadvantages:
– Low energy content due to high fluctuations.
-High cost due to need for higher volume due to low energy content.
-Poor lubrication of parts due to the lack of paraffin wax.
Grade 2 diesel fuel is readily available at most gas stations around the world. Because it has the highest amount of energy components and lubricating properties. It also offers the best fuel efficiency on the market. Generally, No. 2 diesel is cheaper than No. 1 due to the simpler refining process. The paraffin in Grade 2 diesel fuel tends to freeze at low temperatures, often causing hard starting and other problems during the winter. The advantages of grade 2 diesel fuel are:
-Complete combustion -Improved cold start
– Engine noise and impact less
– Reduction of white smoke and heating time
-Less errors
-Less emissions of nitrogen oxide, hydrocarbon, carbon monoxide and suspended particles from the exhaust
Diesel D6, which is known as Residual Fuel Oil, has a high viscosity. This hydrocarbon, which is used as a fuel, needs to be preheated at a temperature between 100 and 125 degrees Celsius before consumption. D6 diesel is a type of residual fuel that It is mostly used for generators and huge engines such as ship engines and power plants. Despite this recent change, D6 is less popular due to its high viscosity, as well as the need to preheat before use, and because it contains large amounts of pollutants such as sulfur, and since it requires preheating, it is used in small ships, boats, or automobiles. cannot be used. D6 is the common name of this fuel in the United States. It has other names in other parts of the world. D6 fuel is also known as Residual Fuel Oil (RFO) by the Navy specification Bunker C or by the Pacific specification PS-400. The name residue hence refers to the fuel that remains after boiling off the more valuable parts of crude oil. The residue may contain various undesirable impurities, including 2% water and 0.5% mineral soil. D6 diesel prices traditionally increase in the colder months as demand for heating oil increases, and refining does so in much the same way. Due to recent changes in D6 fuel quality regulations, additional refining is required to remove sulfur, which sometimes increases the cost of the product. In Sweden, a D6 diesel fuel is also sold as MK-1 (Environmental Diesel Class 1). This fuel is a ULSD or very low sulfur diesel, which has less aromatics (about 5%). This D6 fuel is slightly more expensive to produce than regular ULSD.
The first product of the vacuum distillation tower that is obtained after cutting kerosene is L40 diesel with a specific gravity of 0.830 to 0.840. Considering that the feed unit (crude oil) is based on paraffin, the cetane number of this product is acceptable without any additives to improve cetane. In addition, due to the fact that the food is paraffinic, it also has a favorable freezing point; Therefore, it can be used as a fuel for diesel engines.
This product is the second product of vacuum distillation after cutting L40 diesel and has a specific gravity in the range of 0.840 to 0.860 at a temperature of 15.6 degrees Celsius. L62 diesel product has almost all the features of L40 diesel, the only obvious difference between these two products is in their specific weight and relatively in their color.
