What are lubricant base oils and what are the classifications of lubricant base oils?

Lubricating oil base oils are mainly divided into two categories: mineral base oils and synthetic base oils.

Mineral Base Oils:

Mineral base oils are widely used in large quantities (about 95% or more), but some applications require the use of synthetic base oil blends, which has led to the rapid development of synthetic base stocks.

Mineral oil base oil is refined from **. The main production processes of lubricating oil base oil are: atmospheric and vacuum distillation, solvent deasphalting, solvent refining, solvent dewaxing, clay or hydrogenation supplemental refining.

In 1995, China's current lubricating oil base oil standards were revised, mainly revising the classification method, and adding two types of special base oil standards for low condensation and deep refining. The most important thing in the production of mineral lubricants is to use the best **.

The chemical composition of mineral base oils includes a mixture of high boiling point, high molecular weight hydrocarbons and non-hydrocarbons. Its composition is generally alkanes (straight, branched, multi-branched), naphthenes (monocyclic, bicyclic, polycyclic), aromatics (monocyclic aromatic hydrocarbons, polycyclic aromatic hydrocarbons), naphthenic aromatic hydrocarbons and oxygen-containing, nitrogen-containing, sulfur-containing organic compounds and non-hydrocarbon compounds such as colloids and asphaltenes.

Synthetic Base Oils:

1. Poly-olefin oil: made by polymerization of -olefin. Compared with mineral oil, it has excellent demulsification, excellent resistance to high temperature coking and carbon deposition, excellent viscosity and temperature, good thermal and oxidation stability, good lubricity, low volatility and high cost.

2. Ester oil: it is made of esterification of alcohol and acid. Compared with mineral oil, it has excellent thermal oxidation stability, excellent resistance to high temperature coking and carbon deposition, excellent thermal conductivity, excellent lubricity, excellent demulsification, excellent viscosity and temperature, good lubricity, low volatility and high cost.

3. Silicone oil: polymerized from siloxane. Compared with mineral oil, it has excellent viscosity and temperature, excellent chemical stability, excellent electrical insulation, excellent water and moisture resistance, low volatility, high cost, and poor lubricity.

4. Fluorine oil and fluorochlorine oil: polymerized by fluorinating agent fluorination or fluorinated ethylene. Compared with mineral oil, it has special chemical inertness, excellent thermal stability, excellent lubricity, high cost, and poor viscosity and temperature.

5. Polyether: polymerized from epoxy alkane. Compared with mineral oil, it has excellent thermal conductivity, excellent lubricity, excellent viscosity and temperature, good resistance to light hydrocarbon dilution, good oxidation resistance, and high cost.

Refined base oil - Shandong Jiangshan.

Lubricating oil base oils are divided into:

There are five categories of base oils: Class I, Group II, Group III, Group IV base oil, and Class V base oil.

The sulfur content is greater than that, the saturated hydrocarbon content is less than 90%, and the viscosity index is 80 to 120, which is mainly used for light load situations with low requirements;

The sulfur content is less than 90%, the saturated hydrocarbon content is greater than 90%, the viscosity index is 80 to 120, and the relative properties, purity, color and oxidation resistance are improved;

The sulfur-like content is less than 90%, the saturated hydrocarbon content is greater than 90%, the viscosity index is greater than 120, and the relative viscosity is higher, which can be used for higher requirements and the pollutants are reduced.

It is a synthetic oil, which has a high viscosity index, low volatility, excellent low temperature performance, oxidation resistance and thermal stability to meet the higher and higher performance requirements of lubricating oils;

Classes are all base oils other than the first four categories, including alkylated aromatics and esters, which are usually blended with other base oils to meet specific performance requirements;

The U.S. API classifies base oils into 5 categories according to the main characteristics of base oil composition:

Class I is a solvent-refined base oil with a high sulfur content and unsaturated hydrocarbons (mainly aromatics);

Class II is mainly hydrotreated base oils, which have low sulfur and nitrogen content and aromatic hydrocarbon content;

Class III is mainly hydroisomerization base oil, which not only has low sulfur and aromatic hydrocarbon content, but also has a high viscosity index;

Class IV is a poly-A-olefin (PAO) synthetic oil base oil;

Group V is a variety of base oils other than Group I-IV.

Five categories of differences and advantages:

Class I base oil is mainly refined and produced by physical methods, that is to say, the molecular chemical structure of raw materials will not be changed in the production process, and all properties are based on raw materials. Vice versa. Therefore, this type of base oil is limited in performance.

Group II base oils are produced by chemical methods, using a combination of solvent processes and hydrogenation processes, and their performance is not limited by the properties of raw materials, and can change the original chemical molecular structure. Therefore, the impurities of the group II base oil are relatively much less (the content of aromatic hydrocarbons is less than 10%), the content of saturated hydrocarbons is higher, the thermal stability and antioxidant properties are better, and the low temperature and soot dispersion performance are better than those of the group I base oil.

Group III base oils are hydrogenated base oils with a high viscosity index compared to Group II base oils, also known as unconventional base oils (UCBO). Group III base oils far outperform Group I and Group II base oils in terms of performance, especially with a high viscosity index and very low volatility. Some Group III oils are comparable in performance to poly-olefin (PAO), but are much less expensive than synthetic oils.

Group IV base oils are poly-olefin (PAO) synthetic oils. Commonly used production methods are paraffin decomposition and ethylene polymerization. PAO can be divided into low polymerization, medium polymerization and high polymerization according to different polymerization degrees, which are used to prepare different oils.

Compared to mineral oils, these base oils are free of S, P and metals, and because they do not contain waxes, they have a very low pour point, usually below 40, and a viscosity index of more than 140. But the Pao boundary has poor lubrication. In addition, due to its small polarity, its ability to dissolve polar additives is poor, and it has a certain shrinkage to rubber seals, but these problems can be overcome by adding a certain amount of esters.

Class V base oils (synthetic hydrocarbons, esters, silicone oils, etc.), vegetable oils, recycled base oils, etc.