Basic properties of lubricating oil
Lubricating oil is a technically advanced product composed of a complex mixture of hydrocarbons. Its actual performance is the result of multiple physical and chemical changes that occur simultaneously.
Lubricating oil properties encompass general and special physical and chemical properties, as well as the results of bench simulation tests.
General physical and chemical properties
Each type of lubricating grease has specific general physical and chemical properties that are indicative of its internal quality.
The general physical and chemical properties of lubricating oil are as follows:
Appearance (chromaticity)
The color of a petroleum product can often indicate its level of refinement and stability. Higher refining levels result in the removal of hydrocarbon oxides and sulfides, leading to a lighter color.
However, even if the refining process is identical, the color and clarity of base oils produced from different sources and types of crude oil may vary.
For newly produced lubricating oils, the addition of additives negates the importance of color as an indicator of the refinement level of the base oil.
Density
Density is a simple and widely used physical property of lubricating oil.
The density of lubricating oil increases with increasing carbon, oxygen and sulfur content.
Therefore, under the same viscosity or molecular weight, the lubricating oil with the highest proportion of aromatics, colloids and asphaltenes will have the highest density. Lubricating oil with more cycloalkanes will have a moderate density, while lubricating oil with more alkanes will have the lowest density.
Viscosity
Viscosity is a measure of the internal friction of petroleum derivatives and reflects the oiliness and fluidity of the product.
Without the addition of functional additives, higher viscosity generally corresponds to a stronger oil film but lower fluidity.
Flash point
The flash point is a measure of the rate of evaporation of the oil. The lighter the oil fraction, the higher its evaporation rate and the lower its flash point. On the other hand, heavier oil fractions have lower evaporation rates and higher flash points.
Flash point is also an indicator of the fire risk of petroleum products. The danger level of petroleum products is determined based on their flash point. Products with flash points below 45°C are considered flammable, while those with flash points above 45°C are considered non-flammable.
It is strictly prohibited to heat petroleum products to flash point temperature during storage and transportation.
In general, higher flash points are preferred, especially when choosing lubricating oil based on operating temperature and working conditions. A flash point 20 to 30°C higher than the operating temperature is considered safe for use.
Freezing point and pour point
Freezing point refers to the maximum temperature at which oil stops flowing under specific cooling conditions.
The solidification of petroleum products is different from that of pure compounds and there is no defined solidification temperature for petroleum products. Instead, “solidification” refers only to the loss of fluidity as a whole, as not all components become solid.
The freezing point of lubricating oil is a crucial quality index that indicates its fluidity at low temperatures. It is important for production, transportation and use. Lubricating oil with a high freezing point cannot be used in low-temperature environments, while oil with a low freezing point is unnecessary in high-temperature areas as it increases the production cost.
Normally, the freezing point of lubricating oil should be 5 to 7°C lower than the minimum operating temperature. However, it is important to consider the freezing point, low-temperature viscosity, and temperature and viscosity characteristics of the oil when choosing low-temperature lubricating oil. Oil with a low pour point may not have the desired characteristics of low temperature viscosity and viscosity temperature.
Freezing point and pour point are both indicators of the low-temperature fluidity of petroleum products, but the determination methods are slightly different. Although the pour point and freezing point of the same oil are not always the same, the pour point is generally 2 to 3°C higher than the freezing point, although there are exceptions.
Acid value, alkaline value and neutralization value
The acid number is a measure of the presence of acidic substances in the lubricating oil and is expressed in units of mgKOH/g. It can be divided into strong and weak acidity values, with the combination of the two referred to as the total acid number (TAN). When referring to “acidity value”, it usually means “total acidity value (TAN)”.
The alkaline value is an indicator of the amount of alkaline substances in the lubricating oil and is expressed in units of mgKOH/g. It can also be divided into strong and weak alkaline values, with the combination of the two referred to as total alkaline value (TBN). When referring to “alkaline value”, it usually means “total alkaline value (TBN)”.
The neutralization value encompasses both the total acid value and the total base value, but unless otherwise specified, “neutralization value” normally refers to the “total acid value” and is expressed in units of mgKOH/g.
water content
Water content refers to the percentage of water in the lubricating oil, typically expressed by weight.
The presence of water in lubricating oil can break the oil film and negatively impact lubrication. It also accelerates corrosion caused by organic acids on metal surfaces, causing rust on equipment and increasing the risk of sedimentation.
In short, the lower the water content in the lubricating oil, the better.
Mechanical impurities
Mechanical impurities refer to insoluble precipitates or colloidal suspensions in lubricating oil that cannot be dissolved in solvents such as gasoline, ethanol and benzene.
These impurities generally consist of sand and iron filings, as well as some organic metal salts brought by additives that are difficult to dissolve in solvents.
In general, mechanical impurities in lubricating base oil should be kept below 0.005% (a level of 0.005% or lower is considered absent).
Ash and sulphated ash
Ash refers to the non-combustible substances that remain after burning under specific conditions.
Ash typically consists of metallic elements and their salts.
The concept of ash may vary for different petroleum products. For base oils or derivatives without additives, ash can be used to evaluate the depth of refining of the product. For petroleum products with metal salt additives, ash serves as a means of quantifying the amount of additives added.
In some foreign countries, sulfuric acid ash is used as an ash substitute. This involves adding a small amount of concentrated sulfuric acid to the oil sample after burning but before it is incinerated, converting the metallic elements in the additive to sulfate.
Residual carbon
Under the specified experimental conditions, the black residue that forms after the heated evaporation and combustion of petroleum products is called Carbon Residue.
Carbon Residue is an essential quality index for base lubricating oils, used to determine their nature and depth of refining.
The amount of carbon residue in the lubricating oil base oil is influenced not only by its chemical composition, but also by the oil's refining depth.
The main components that contribute to carbon residue in lubricating oil are gum, asphaltene and polycyclic aromatic hydrocarbons.
In conditions of insufficient air, these substances undergo intense thermal decomposition and condensation, leading to the formation of Carbon Waste.
Typically, the deeper the oil refining depth, the lower the Carbon Residue value.
As a general rule, the lower the Carbon Residue value of the base oil, the better its quality.
However, many petroleum products now contain additives of metallic elements, sulfur, phosphorus and nitrogen, which result in high Carbon Residue values.
Therefore, the Carbon Residue of the added oil no longer maintains its original meaning in determining the quality of the oil.
Mechanical impurities, moisture, ash and carbon residues are quality indicators that reflect the purity of petroleum derivatives and the depth of refining of the lubricating base oil.
Special physical and chemical properties
In addition to general physical and chemical properties, each lubricating oil must also have specific physical and chemical properties that characterize its usage characteristics.
The higher the quality requirements or the more specific the application of the oil, the more pronounced its unique physical and chemical properties become.
The following are brief introductions to test methods that reflect these special physical and chemical properties:
Oxidation stability
Oxidation stability refers to the anti-aging performance of lubricants.
For industrial lubricants with a long service life, this index is a requirement and has become a specific performance requirement for these types of oils.
There are numerous methods for determining the oxidation stability of petroleum products.
Essentially, a specific amount of oil is subjected to oxidation at a specific temperature over a set period of time in the presence of air (or oxygen) and metal catalysts. The resulting acidity value, viscosity change and sediment formation of the oil are then measured.
All lubricants have varying tendencies to self-oxidize, depending on their chemical composition and external conditions.
With use, oxidation occurs and some substances such as aldehydes, ketones, acids, colloids, asphaltenes and others are gradually generated.
Oxidation stability is the action of inhibiting the formation of these substances, which are harmful to the usability of petroleum derivatives.
Thermal stability
The quality of thermal stability refers to the high temperature resistance of petroleum products, or the ability of lubricating oil to resist thermal decomposition, specifically, the thermal decomposition temperature.
Some high-quality anti-wear hydraulic oils and compressor oils have established thermal stability requirements.
The thermal stability of petroleum derivatives depends mainly on the composition of the base oil.
Many additives with low decomposition temperatures can have a negative impact on the stability of petroleum products.
Antioxidants cannot significantly increase the thermal stability of petroleum products.
Oiliness and extreme pressure
Oiliness refers to the ability of polar substances in lubricating oil to form a solid physical and chemical adsorption film on the metal surface of friction parts, providing resistance to high loads and reducing friction and wear.
Extreme pressure refers to the decomposition of polar substances in the lubricating oil on the metal surface of friction parts under high temperature and high load, resulting in a reaction with the metal surface to form an extreme pressure soft (or plastic) film with low point fusion point.
This film provides lubrication and resistance to impacts, high loads and high temperatures.
Corrosion and rust
Oil oxidation or the effects of additives can often lead to corrosion of steel and other non-ferrous metals.
A typical corrosion test involves placing a red copper bar in oil and exposing it to 100°C for 3 hours, followed by observing any changes in the copper.
Another corrosion resistance test is performed by exposing steel surfaces to rust under the action of water and steam.
Determining rust resistance involves adding 30ml of distilled water or artificial seawater to 300ml of test oil and then placing a steel bar into the mixture, stirring at 54℃ for 24 hours and observing whether the steel bar is corroded.
Petroleum products must have the ability to resist metal corrosion and rust. These two properties are normally tested and required in industrial lubricant standards.
Anti-foam property
During the operation of lubricating oil, the presence of air often leads to foaming, especially when the oil contains surfactant additives. Foam is difficult to dissipate and its formation can have negative consequences.
The generation of foam in the lubricating oil can destroy the oil film, cause sintering of the friction surface or increase wear, accelerate the oxidation and deterioration of the lubricating oil, and increase air resistance in the lubrication system, affecting the circulation of the lubricating oil . Consequently, antifoam is a crucial quality index for lubricating oil.
Hydrolytic stability
Hydrolytic stability describes the stability of the oil when exposed to water and metals (mainly copper).
If the oil has a high acidity index or contains additives that easily decompose into acidic substances when it comes into contact with water, this index is usually unsatisfactory.
The measurement method involves adding a specific amount of water to the test oil, mixing and shaking the copper strip at a certain temperature for a certain period of time, and then measuring the acid value of the water layer and the loss of weight of the copper strip. .
Demulsibility
In industrial use, lubricating oil is often mixed with some cooling water.
If the lubricating oil has weak anti-emulsifying properties, it will form an emulsion with the mixed water, making it difficult to separate and discharge water from the bottom of the circulating oil tank, leading to poor lubrication.
Therefore, demulsibility is a crucial physical and chemical property of industrial lubricants.
Normally, 40ml of test oil and 40ml of distilled water are stirred vigorously at a specific temperature for a certain period of time, and then the separation time of the oil layer, water layer and emulsion layer at 40-37 -3ml is observed.
For industrial gear oil, the test involves mixing the oil with water, shaking for 5 minutes at a specific temperature and 6,000 rpm, letting it sit for 5 hours, and then measuring the milliliters of oil, water and emulsion layer.
Air release value
The hydraulic oil standard requires that the oil has good air release properties, because in hydraulic systems, if the air dissolved in the oil is not released in a timely manner, it may affect the precision and sensitivity of the hydraulic transmission and, in serious cases, , fail. to meet hydraulic system requirements.
The method of measuring this property is similar to that of defoamer, but measures the air release time (MIST) dissolved in the oil.
Rubber grip
In hydraulic systems, rubber is commonly used as seals.
Petroleum products in machines inevitably come into contact with some seals.
Petroleum products with poor rubber compatibility can cause swelling, shrinkage, hardening and cracking, affecting its sealing ability.
As a result, petroleum derivatives must have good compatibility with rubber.
The hydraulic oil standard requires a rubber seal index, which is determined by observing the change in size of a rubber ring after being soaked in oil for a certain period of time.
Shear stability
When using oil with tackifiers, mechanical shear can cause the oil's high molecular weight polymer to break down, reducing its viscosity and impairing normal lubrication.
As a result, shear stability is a crucial physical and chemical property that must be tested for this type of oil.
There are several methods for determining shear stability, including the ultrasonic shear method, the nozzle shear method, the Vickers pump shear method, and the FZG sprocket shear method.
Ultimately, these methods measure the rate of decline in the oil's viscosity.
Solubility
Solubility is often measured by the aniline point.
Different grades of oil have different aniline points, which represent the solubility limit for compound additives. The limit value for low ash oil is higher than that of peralkaline oil, and the limit value for single-stage oil is higher than that of multi-stage oil.
Volatility
Base oil volatility affects fuel consumption, viscosity stability and oxidation stability.
These properties are especially crucial for multi-stage oils and energy-saving oils.
Rust resistance
Refers to the specific physical and chemical properties of anti-rust grease.
Its testing methods include moisture test, salt spray test, lamination test, water displacement test, as well as shutter box test, long-term storage test, etc.
Electrical performance
Electrical performance is a unique characteristic of insulating oil, mainly consisting of dielectric loss angle, dielectric constant, breakdown voltage, pulse voltage, etc.
Refining depth, impurities and moisture in the base oil significantly impact the electrical performance of petroleum products.
Special physical and chemical properties of lubricating grease
In addition to the general physical and chemical properties of lubricating grease, specialized grease has specific physical and chemical properties.
For example, a grease with good water resistance requires a water immersion test;
Low-temperature grease must pass a low-temperature torque test;
Multipurpose grease must be tested for resistance to wear under extreme pressure and rust;
Long-life grease must pass a bearing life test.
There are corresponding test methods to determine these properties.
Other special physical and chemical properties
In addition to general performance, each petroleum product must have its own special and unique performance.
For example, the cooling rate of quenching oil must be measured;
The emulsified oil must pass an emulsion stability test;
The anti-creep coefficient should be measured for hydraulic guide rail oil;
Spray lubricating oil must be tested for oil mist diffusivity;
The coagulation point of the refrigerant oil must be determined;
Low temperature gear oil should be tested for pour point formation, etc. These characteristics require a special chemical composition of the base oil or specific additives to be guaranteed.
Instructions for using lubricating oil:
Oil Storage:
- To prevent water and debris intrusion, do not store the oil drum in an upright position outdoors.
- To facilitate extraction, internal storage can be done vertically with the barrel facing upwards.
- Make sure the sealing cap is tight to keep the oil barrel sealed.
- Maintain a clean and clear surface on the oil barrel.
- Keep the ground clean to promptly detect oil leaks.
- Maintain proper warehouse records on a first-come, first-serve basis.
- Store frequently extracted oil on the oil barrel shelf and control the discharge using a switch.
- Store new oil and used oil separately. Containers filled with used oil should not be reused for new oil to avoid contamination.
Oil safety:
- Store petroleum products separately and keep flammable products away from the storage area.
- Prohibit the use of fireworks and ignition sources in the oil depot.
- Equip the storage area with at least two fire extinguishers.
- Do not allow tarps or oil residue to accumulate after cleaning machines, as this may increase the risk of fire.
- Store flammable special petroleum products and chemical solvents separately, and clearly mark the storage area with flammability signs.
Usage Notes:
- To minimize the use of different types of oil, consult lubrication experts and use lubricants with the appropriate specifications.
- Display a simple diagram on each machine showing the parts that require lubrication, the name of the petroleum product and the lubrication cycle, and assign a designated person to ensure that the correct petroleum product is used.
- Clean and wipe down containers and tools, such as oil pumps and oil kettles, before refilling.
- Clearly mark each oil container with the name of the oil it contains to avoid contamination.
- Before changing the oil, clean the machine with solvent. Do not use water-soluble cleaning agents.
- Keep records of mechanical maintenance after each oil addition or change.
- If any abnormal petroleum products are detected or the oil change cycle has expired, collect samples and send them to a professional company for testing and verification.
Environmental protection and health:
- It is strictly prohibited to discharge used oils directly into ditches or soil, as this may cause environmental pollution.
- Collect used oil and waste liquid in special barrels and deliver them to a government-approved recycling company for proper disposal. Don't discard them randomly.
- People with skin allergies or skin abrasions should avoid direct contact with lubricating oil.
- Do not wear oil-stained clothing and do not place oil-contaminated rags in bags.
- When cleaning oil stains from your skin, do not use dirty rags as this can cause skin infection due to metal debris that may be present on the rags.
Glossary of technical terms
Abrasive Wear: Mechanical wear caused by the sliding of two contact surfaces in relative movement.
Additive: A small amount of substances added to improve lubrication performance.
Adhesion improver: Additives added to oils and greases to improve adhesion, such as polyisobutylene.
Adhesion Lubricant: A lubricant that contains an adhesion modifier to prevent sagging due to centrifugal force.
AF Coating (Anti-Friction Coating): The most widely used dry film solid lubricant, which can be cured at room temperature or with heat. The formula consists of solid lubricating materials (known as “raw materials”) and binding materials, see “Binder”.
Anti-aging: Aging of materials caused by factors such as oxidation, overheating or the presence of certain metals (e.g. copper, lead, silver). The aging resistance of materials can be improved by adding additives such as antioxidants.
ASTM: American Society for Testing and Materials.
Base Oil: The fundamental components of lubricating oil and grease.
Binder: A non-volatile medium or excipient used to improve the bond between particles of solid lubricating material or to increase adhesion between the solid lubricating film and the friction surface.
Loosening torque: The force required to loosen a bolt connection.
Chemical Inertness: A lubricant that does not react with certain substances.
Coefficient of friction: The relationship between the friction force and the normal force between two contacting surfaces.
Low temperature performance: Cloud point, pour point and freezing point are used to evaluate the performance of lubricating oil, while Kesternich flow pressure and low temperature torque tests can be used to measure the lubricating grease.
Colloid: Particles in a stable liquid ranging in size from 10^-5 to 10^-7 cm, used as a solution without particle sedimentation.
Composite Grease: Lubricating grease made with a metallic soap thickener and various acids, especially suitable for high temperatures and prolonged use.
Consistency: A lubricating grease index that is divided into non-functional cone penetration and functional cone penetration and is measured according to the NLGI (National Lubricating Grease Institute) standard.
Simply divide the consistency into nine grades, such as:
| Degree of consistency | Working taper (1/10mm) |
| 00 | #:400-430 |
| 0 | #：350—385 |
| 1 | #：310—340 |
| two | #：265—295 |
Density: The mass of the lubricant per unit volume at 20°C, expressed in g/cm 3 .
Detergents: Surfactants that remove surface residues and sediments.
Dispersibility: Improves the dispersibility of insoluble substances in a liquid.
DN value: A reference value for the rotational speed of bearing grease, expressed as the bearing pitch diameter (mm) multiplied by revolutions per minute.
Drip point: The temperature at which the lubricating grease changes from the semi-solid state to the liquid state, indicating the heat resistance of the lubricating grease. The drip point temperature is defined as the temperature at which the first drop falls from the container as the temperature increases.
Dynamic Viscosity: Also known as absolute viscosity, which reflects the internal resistance between fluid molecules during the flow of lubricating oil. It is measured by the flow of lubricating oil through a tube or slot.
EP Additive: Chemical substance used to improve the ability to withstand heavy loads and high temperatures, increasing the wear resistance of oils and greases.
Emcor: A corrosion resistance test for bearing lubricating grease in water. At least two grease-lubricated bearings are tested after running in water for about a week. The corrosion resistance value ranges from 0 to 5, with 0 indicating no corrosion and 5 indicating severe corrosion.
Ester Oil: Compounds of acids and alcohols used as lubricating materials and in the production of lubricating greases.
Flash Point: The lowest temperature at which a mixture of oil vapor and air will ignite and ignite.
Fluorosilicone Oil: A silicone oil containing fluorine atoms in its molecules.
Frictional corrosion wear: A type of mechanochemical wear caused by slight sliding of two contacting bodies, resulting in corrosion on the friction surface and accumulation of oxide chips between the friction surfaces.
Friction: The phenomenon of tangential resistance at the contact interface of two objects in relative motion.
Grease: Lubricating medium composed of base oil and a thickener.
Inhibitor: An additive used in lubricants to delay aging and corrosion.
Freezing point: The maximum temperature of the petroleum product when the cooled oil sample no longer moves under specified test conditions, expressed in °C.
Pour point: The lowest temperature at which a cooled sample can flow under specified test conditions, expressed in °C. It is a conventional index used to measure the fluidity of lubricating oil at low temperature. The pour point is slightly higher than the freezing point. Previously, pour point was commonly used, but now freezing point is widely used internationally.
Lubricating oil development outlook
In the next decade, demand for lubricating oil in the Asia-Pacific region is expected to reach 15.5 million tons, with China responsible for 40% of the region's demand.
In 2020, demand for lubricants in China doubled and surpassed that of the United States.
The rapid growth of domestic demand for automobile oil and the trend towards high-quality automobile oil will lead the automobile lubricant industry into a period of rapid development.
As demand for automotive lubricants continues to increase, so does the quality of petroleum, with high-quality petroleum products directly aligned with international standards.
Does high viscosity of lubricating oil indicate good quality of lubricating oil?
In general, when the operating speed of components is high, the surface load is likely to be lower and the corresponding lubricating oil is expected to have a lower viscosity, such as spindle oil. On the other hand, if the operating speed is low, the surface load will be greater and the lubricating oil must have a higher viscosity, such as gear oil. However, it is important to emphasize that the lubricating oil must meet the standards established by the equipment supplier for oil selection.
It is important to highlight that the quality of lubricating oil cannot be assessed solely based on its viscosity, as it has several other indicators to be considered.
Lubricant
Lubricating oil is generally produced from fractionated oil or refined vegetable oil. It is also known as grease and is a non-volatile lubricating oil. According to their sources, lubricating oils can be divided into animal and vegetable oils, petroleum lubricants and synthetic lubricants.
Petroleum lubricating oil accounts for more than 97% of total consumption, and as a result, lubricating oil is often used interchangeably with petroleum lubricating oil. The main purpose of lubricating oil is to reduce friction between moving parts and it also serves as a cooling agent, seals surfaces, prevents corrosion and rust, provides insulation, transmits power, cleans impurities and much more.
The raw materials for the production of lubricating oil are the lubricating oil fraction and the residual fraction from crude oil distillation units. Components such as free carbon forming substances, low viscosity index substances, substances with low oxidation stability, paraffin and color affecting chemicals are reduced or removed through processes such as solvent deasphalting, solvent dewaxing, solvent refining , hydrofining, acid-base refining and clay refining. The result is a qualified lubricating oil base oil.
After additives are added, the base oil becomes a lubricating oil. The main properties of lubricating oil are viscosity, oxidation stability and lubricity, all closely related to the composition of lubricating oil fractions.
Viscosity is an important quality indicator that reflects the fluidity of the lubricating oil. Different service conditions have different viscosity requirements, with high viscosity lubricating oil being preferred for heavy loads and low speed machines.
Oxidation stability refers to the ability of the petroleum product to resist oxidation in service environments due to temperature, air oxygen, and metal catalysis. Oil oxidation results in the formation of fine asphaltene-based carbon substances, viscous paint-like substances, or paint films, or viscous aqueous substances, which reduce or eliminate the oil's performance.
Lubricity is a measure of the lubricating oil's ability to reduce friction.
Function of lubricating oil
Lubricating oil is a liquid lubricant used in various types of machines to reduce friction, protect machines and extend the life of machined parts. It performs several important functions, including lubrication, cooling, rust prevention, cleaning, sealing and cushioning. Lubricating oil represents 85% of all lubricants used and there are numerous brands available with an annual consumption rate of approximately 38 million tons worldwide.
General requirements for lubricating oil include:
- Reducing friction and wear, reducing frictional resistance to save energy, and extending mechanical life to improve economic benefits.
- Provides effective cooling by discharging frictional heat from the machine at all times.
- Sealing to prevent leakage, dust and cross gas.
- Providing corrosion resistance and rust prevention to protect the friction surface from oil deterioration or external erosion.
- Cleaning and washing to remove dirt in the friction area.
- Provides stress dispersion, load dispersion, impact mitigation and shock absorption.
- Transmitting kinetic energy, acting on hydraulic systems and controlling friction in engines for continuous speed change.
Lubricating oil consists of a base oil and additives. The base oil is the main component of the lubricating oil and determines its basic properties. Additives are used to improve base oil performance and add new properties, making them an important part of the lubricating oil.
Lube oil storage
Barrel and canned lubricating oils should be stored in a warehouse to protect them from the effects of weather.
Open barrels of lubricating oil should be kept in the warehouse and stored horizontally with both ends firmly fixed with wooden wedges to prevent rolling.
Regularly inspect barrels for leaks and make sure the markings on their surfaces are clear.
If it is necessary to store the barrel vertically, it is advisable to turn it upside down, with the lid facing downwards, or tilt it slightly to prevent rainwater from accumulating on the surface and potentially flooding the back of the barrel.
Water can have negative effects on lubricating oils, and although it is not easy to penetrate the pipe cover, it can enter the pipe if the pipe is exposed to extreme temperature changes.
Exposure to hot sun during the day and cold temperatures at night can cause thermal expansion and contraction, leading to changes in air pressure inside the barrel. This “breathing” effect can cause air to be expelled from the barrel during the day and inhaled again at night, potentially bringing water into the barrel if the lid is immersed. Over time, this can result in a significant amount of water mixing with the oil.
When dispensing oil, place the barrel on a wooden frame of suitable height and use a tap on the lid to drain the oil into a container to prevent drips. Alternatively, insert an oil tube into the end of the pipe and use a hand pump to distribute the oil.
When storing bulk oil in a tank, it is inevitable that condensation and dirt will mix and form a layer of sludge at the bottom, potentially contaminating the lubricating oil. To avoid this, the bottom of the tank should be designed in a butterfly shape or inclined, and a drain tap should be installed to regularly discharge waste. Regular cleaning of the tank interior is also recommended.
Lubricating grease is more sensitive to temperature changes than lubricating oil. Prolonged exposure to high temperatures (such as sunlight) can cause the oil components in lubricating grease to separate, so it is important to store barrels of lubricating grease in a warehouse, with the barrel mouth facing upwards.
The larger opening of lubricating grease cylinders makes it easier for dirt and water to penetrate, so be sure to close the end of the cylinder immediately after dispensing.
Lubricating oils should not be stored in very cold or very hot areas for long periods of time, as extreme temperatures can have adverse effects on the oil.
Lubricant Base oil
Lube oil base oils are mainly categorized into mineral and synthetic base oils. Although mineral base oils are widely used and make up a large portion of the market (about 95% or more), certain applications require products blended with synthetic base oils, leading to rapid growth in the use of synthetic base oils.
Mineral base oils are derived from crude oil and undergo various refining processes such as atmospheric and vacuum distillation, solvent deasphalting, solvent refining, solvent and clay dewaxing, or hydrorefining.
In 1995, the standard for lubricating base oils in China was updated, with a modification in the classification method and the addition of two special base oil standards for low pour point and deep refining. Selecting the best crude oil is crucial in the production of mineral lubricants.
The chemical composition of mineral base oils includes high-boiling hydrocarbons with high molecular weight and non-hydrocarbon mixtures. These compositions typically consist of alkanes (linear chain, branched chain and multi-branched chain), cycloalkanes (monocyclic, bicyclic and polycyclic), aromatics (monocyclic and polycyclic), cycloalkyl aromatics, oxygen-containing, nitrogen-containing, sulfur-containing. containing organic compounds, colloids, asphaltenes and other non-hydrocarbon compounds.
In the past, major foreign oil companies classified base oils based on the nature and processing technology of crude oil into categories such as paraffin base oil, intermediate base oil and naphthenic base oil. However, with the trend toward low-viscosity, multi-grade, and universal engine oils in the 1980s, higher viscosity index requirements were imposed on base oils. As a result, the original classification method became obsolete and foreign oil companies began classifying base oils based on viscosity index without a strict standard.
In 1993, API introduced a five-category classification system for base oils (API-1509) and incorporated it into the API Engine Oil Licensing and Certification System (EOLCS).
