Bitumen is one of the petroleum products that is derived from processes such as distillation and evaporation of crude oil. Tar is a complex chemical substance that includes a mixture of aromatic and aliphatic hydrocarbons.
Bitumen, also known as heavy distillation residue, is a variable fraction of crude oil, ranging from zero to more than half of it. Moreover, Bitumen obtained from different sources can have significant differences.
The history of Bitumen dates back to human discovery of crude oil. Bitumen has been used as an ideal material in various construction projects since ancient times. Due to its properties such as water resistance and desirable mechanical properties, it has been widely used in general construction.
The history of Bitumen dates back to human discovery of crude oil. Bitumen has been used as an ideal material in various construction projects since ancient times. Due to its properties such as water resistance and desirable mechanical properties, it has been widely used in general construction. Some uses of Bitumen include asphalt coating on roads, waterproofing roofs and floors, as well as in various oil and gas industries.
The important application of Bitumen is due to its two key properties: impermeability to water and high adhesiveness. Based on these characteristics, tar is mainly used in road construction and insulation work.
The use of tar dates back more than 5,000 years.
Ancient Susa artists obtained a mixture of tar and calcite by heating this substance, which had a great resemblance to stone. They used this material for making various objects, sculptures, and reliefs.
In the early 20th century, petroleum tar obtained from crude oil refining entered the market and replaced natural and mineral tars in asphalt pavements and other industrial uses. These types of tars are obtained from crude oil refining in distillation towers and remain at the bottom of the tower at temperatures above 380 degrees Celsius.
Tar storage tanks:
Fixed emulsion tar tanks (horizontal and vertical) should be double-walled and have a hot oil pipeline system. In addition to being double-walled and having a hot oil pipeline, these tanks should be equipped with a mixer for circulation.
The use of vertical tanks in emulsion tar storage has priority over horizontal tanks, as the lower contact surface of tar with air in vertical tanks reduces the degradation of emulsion tar’s useful life.
Transportation of emulsion tars with double-walled tankers:
The use of double-walled insulated tankers prevents temperature loss during loading and also saves fuel consumption. It also helps to reduce time spent during discharge and increase safety by eliminating the need to heat tar during discharge. It also does not pollute the environment.
Additionally, tar can be classified based on other properties such as penetration rate, softening point, flash point, density, color, etc.
The classification of tar is carried out based on its properties and applications. One of the tar grading systems is the Penetration system, which is determined based on the hardness and softness of tar. In this system, tar is categorized based on the number representing the depth in millimeters to which a standard needle penetrates the tar in 10 seconds at a temperature of 25 degrees Celsius. For example, 60/70 tar means that the tar penetrates to a depth of 25 millimeters at a temperature of 25 degrees Celsius. Different grades of tar are used in the construction and road industry, with each grade suitable for specific applications.
Types of petroleum tar and analysis:
During the distillation of crude oil, lighter oils evaporate at lower temperatures, and as the temperature increases, heavier oils separate. What remains at the bottom of these towers is pure tar, which can be obtained by adjusting the temperature and pressure inside the distillation tower to obtain tars with different levels of hardness.
Blown tars are obtained from blowing hot air into pure tar in the final stage of purification. The pure tar, which is in liquid form and at high temperature, is introduced into a special chamber, and it is blown from the bottom of this chamber using perforated air pipes. This operation is usually carried out at temperatures between 200 to 300 degrees Celsius, and the tar acquires the desired properties.
Emulsified tars have advantages such as not requiring heating during use, not requiring intermediate solvents for preparing liquid tar, non-flammability during storage, transportation, or use, and not polluting the environment. Emulsion tars are used in road construction for purposes such as producing cold mix asphalt, surface asphalt, tack coat, slurry seal, and also have applications