Composition and classification of crude oil in industrial lubricants

The crude oil in industrial lubricants is a brownish black flammable viscous liquid extracted from deep underground. It is a mixture formed by the long-term evolution of organisms in ancient oceans or lakes. Petroleum is mainly composed of two elements, carbon and hydrogen, including hydrocarbons and non hydrocarbon compounds. Its main compounds are hydrocarbons such as alkanes, cycloalkanes, and aromatic hydrocarbons. Non hydrocarbon compounds include compounds containing sulfur, oxygen, and nitrogen, as well as small amounts of metal sulfides, oxides, nitrides, organic compounds, and composite organic compounds composed of small amounts of sulfur, oxygen, nitrogen, and metals. The main chemical elements that make up petroleum are carbon (83%~87%), hydrogen (11%~14%), and the rest are sulfur (0.06%~0.8%), nitrogen (0.02%~1.7%), oxygen (0.08%~1.82%), and trace metal elements (nickel, vanadium, iron, etc.). The hydrocarbons formed by the combination of carbon and hydrogenation are the main components of petroleum, accounting for about 95% to 99%. Generally speaking, compounds of sulfur, oxygen, and nitrogen are harmful to petroleum products and should be removed as much as possible in petroleum processing. The structure and proportion of various hydrocarbons in petroleum from different origins vary greatly, but they mainly belong to three categories: alkanes, cycloalkanes, and aromatic hydrocarbons. Crude oil in industrial lubricants is a liquid hydrocarbon at room temperature, containing solid components such as wax and asphalt. The combination of carbon and hydrogen increases in boiling point with the increase of carbon elements in the molecule. The carbon number of petroleum products is generally 3-4 for liquefied petroleum gas and 5-10 for gasoline, followed by kerosene, diesel, lubricants, asphalt, etc. 1.1.2 Classification of Crude Oil

According to different chemical compositions, crude oil can be divided into several categories, including paraffin based (alkanes>70%), cyclic based (cycloalkanes>60%), intermediate based (alkanes, cycloalkanes, and aromatic hydrocarbons with similar content), and asphaltene based (asphaltene>60%). In addition, crude oil is also divided into low sulfur crude oil (<0.5%), sulfur-containing crude oil (0.5%~1.5%), and high sulfur crude oil (>1.5%) according to their high and low content. Crude oil mainly composed of alkanes is called crude wax based crude oil, crude oil mainly composed of cycloalkanes and aromatic hydrocarbons is called cyclic hydrocarbon based crude oil, and crude oil between the two is called intermediate base crude oil. 1.1.3 Properties of Crude Oil The properties of crude oil vary depending on the place of origin, with a density of 0.8~1.0g/mL, a wide viscosity range, and a large difference in freezing point (-60~muscle). The boiling point range is above 500 zhang. It is soluble in various organic substances and insoluble in water, but can form emulsions with water

⑴ Paraffin based crude oil

Gasoline obtained from paraffin based crude oil has a low octane number, kerosene has good combustibility, and diesel has a high cetane number. This type of crude oil is suitable for producing high-grade lubricating oils and solid waxes with high viscosity indices. The main characteristics of Daqing crude oil in China are high wax content, high pour point, low sulfur content, and it belongs to low sulfur paraffin based crude oil.

(2) Cycloalkyl crude oil

This crude oil is refined to produce gasoline with high octane value, poor combustibility of kerosene, low cetane number of diesel, and low pour point of light lubricating oil fractions, making it a good raw material for electrical insulation oil. Cycloalkyl crude oil is one of the noblest types of crude oil in the world, with reserves accounting for only 2% of the total crude oil reserves 2%. Currently, only the United States, Venezuela, and China have resources of cyclic alkyl crude oil in the world. From the characteristics of cyclic alkyl crude oil, the chemical composition of its lubricating oil fractions is mainly composed of cycloalkanes and aromatic hydrocarbons, with less straight chain paraffin hydrocarbons and lower pour point. It is a good raw material for producing electrical and refrigeration oil, as well as suitable for producing white oil, cosmetic oil, and special process oil.

(3) Intermediate base crude oil

The quality of kerosene produced from intermediate base crude oil is good, and the octane value of gasoline is not high, which can be used to produce lubricating oil, heavy oil, Tochige oil, etc.