Manufacture of oil > Base oils > Aircraft oils > Engine oils
Base oils according to the composition may be petroleum, synthetic or semisynthetic.
Petroleum base oil - obtained from the residue (oil) formed after atmospheric distillation of crude oil and removing therefrom gasoline and diesel fractions. The residue is subjected to further processing, including vacuum distillation, purification, deasphalting, dewaxing and others. Refinery processes: distillation -vakuumnaya eliminates the high boiling components (tar) and divided into a number of processed product fractions (distillates) having different boiling temperatures, and thus and the different molecular weight, composition and properties (density, viscosity, viscosity index, flash point and others.); - Cleaning (selective, sulfuric acid, hydrotreating, adsorption, etc.) Is performed to remove undesirable components (sulfur and oxygen-containing compounds, unsaturated hydrocarbons, et al.), Which are in the process oils can have a detrimental effect. The above purification methods selected depending on the process scheme may be used alone or in combination with other methods.
- Deasphalting is carried out to remove the highly viscous residue after vacuum distillation of asphaltenes - Macromolecular products causing increased sludging and lakoobra-tion when using oils. Purified oil fraction is used as component base oils.
- Dewaxing is used to remove distillates and deasfaltiza-ing high melting wax, pour point increase.
The processes of production and purification of base oils may be combined in various ways.
Distillate base oil - components are typically prepared by the following scheme:
a) oil -> vacuum distillation -> selective treatment -> dewaxing -> hydrotreating,
and the fraction > 500 0C under the scheme:
b) tar -> deasphalting -> selective treatment -> dewaxing -> hydrotreating.
Compounded prepared by mixing base oils and residual distilyatnyh components. Mixing of the components is carried out as to obtain the desired viscosity and to achieve the desired composition of the hydrocarbon base oils
Petroleum base oils produced by conventional production and purification schemes are complex mixtures of hydrocarbons (isoparaffin, naphthene-p-paraffins, naphthenic, aromatic, cyclic aromatic varying degrees) with a molecular weight of 300-750 and a molecular composition containing 20-60 atoms carbon and hetero-compounds (containing oxygen, sulfur, nitrogen and some metals). These oils have a viscosity index of about 90-100 units.
Synthetic base oils produced by targeted synthesis of organic and organometallic compounds with properties superior hydrocarbons of petroleum oils. Represent a mixture of chemical compounds of the same or different structure. The largest application received synthetic hydrocarbons (polyolefins, alkylated aromatics), polyethers, esters of organic and inorganic acids, esters of polyhydric alcohols, poly-halogenated hydrocarbons are siloxy et al. Development of synthetic oils started at the end of the XIX century., And in the early 20-ies of XX century. they are already commercially available. By this time the first attempts of their use in lubricating oils. However, their widespread use has begun in the last three decades. Synthetic base oils are superior oil for low-temperature characteristics, thermal stability and oxidation resistance, but inferior to them at cost.
Semisynthetic base oils are usually obtained by mixing synthetic and petroleum components, which allows to obtain products which combine high performance lubricants, superior oil and their reasonable cost.
Particular important is the base oils obtained with use of technology hydrocracking (HC - synthesis of) lube oil. In this process, all hydrocarbon groups and classes of compounds with hydrogen (hydrotreating) in the presence of particular catalysts at elevated temperatures (360-420 * C) and pressure (10-20 MPa) undergo profound transformations.
Application of the hydrocracking process ensures the necessary quality of oil is not due to the removal of unwanted components, as is customary in conventional processes, but due to the chemical conversion of undesirable components in the desired. The raw material for the preparation of lubricating oils are distillates boiling deasphalting and is a complex mixture of hydrocarbons of various groups, hetero (containing sulfur, nitrogen, oxygen, and other elements.) As well as high molecular weight compounds (tar, asphalt). . When processing paraffinic feedstock occurs isomerization of paraffinic hydrocarbons, which also improves the viscosity properties of the products.
In performance lubricating oils produced using hydrocracking products are not inferior to conventional synthetic and semi-synthetic oils, but have a lower price. Depending on the composition of the base oils derived from hydrocracking technology, relates to synthetic or semisynthetic types.
For the production of lubricants and related products including greases require purified base oil with varying levels of viscosity and different properties: composition, oxidation resistance, viscosity-temperature characteristics. As a rule, paraffinic and naphthenic feedstock is processed at the same major oil refineries. Two kinds of products varying degrees of purification, which must meet all the requirements for quality and be inexpensive. However, due to the depletion of sources of raw materials in recent years, naphthenic oil became scarce; therefore only a few refineries still receives a limited amount of oil of this type, and it is not always possible to find a replacement.
Obtained from crude oil, typically three to five oil distillates including refined residual fraction> 500 0C, the number and depth of the distillate depends on the purification requirements specified.
The extracts were also selective treatment is used as base oils for the so-called "dark" process oils. Their composition and viscosity differ depending on the cleaned oil boiling range fraction, the nature and depth of the oil purification. When shallow purification, vysokoaromatizirovannye extracts with high sulfur content. Of the individual fractions using individual depth cleaning, receive various finished products: transformer, white and light oil technology.
All fractions and extracts, raffinates, which are not subjected to post treatment are placed in separate containers. For oils with specified standards outside viscosities spend blending (mixing) oil components with similar viscosity. The reduced viscosity to the desired value by mixing fractions with boiling range, significantly different from each other, spend only on special occasions; the same applies to obtaining a three- or multi-component mixtures, where the boiling range deliberately expanded by the addition of light or heavy fractions to fractions with medium viscosity..
Fractions were mixed lubrication oils, not only to achieve the required viscosity, but also to obtain a mixture of certain hydrocarbon oils using various kinds of raw materials, and furthermore, to stabilize the properties of lubricants.
This is particularly necessary in the case of dark process oils, which require a specific viscosity and specific structural characteristics.
Oil fractions used in the future to produce finished products, usually regarded not as a commodity product, but as for the selection of the viscosity of the mixture
If required high oxidation stability, a better water separation, anticorrosive properties, viscosity index in the range of 90-110, the oil should be applied in the following range of viscosity grades by ISO: 32, 48, 68, 100. oils must meet strict requirements in respect of the low temperature performance .
For the lubrication of objects with mixed types of friction (sliding friction with high load, change the direction of sliding or rolling, frequent starts and stops) are recommended oils containing oil-soluble anti-wear additives. Solid lubricants such as MoS2 or graphite, are added to oils only in special cases, as they can be planted out and impede its oil supply. Oils containing oil-soluble anti-wear additives and meet the requirements of the lubrication mechanisms at high loads. Oils with lower content of additives does not meet the requirements of the standard in relation to the bearing capacity at high loads, but they are used in many cases for some types of equipment for cost reasons.
Cravnivaya properties of different types of oils according to the standards clearly discernible limits on the use of certain types of oils, especially their suitability for use in harsh conditions under which requirements increase the ability of the oil to maintain its performance characteristics in contact with water and air. Minimum requirements in the standards based on the experimental data obtained in more than 10 trials. Selection depends on the viscosity of the speed, load and temperature of operation most heavily loaded node. Machine builders usually determine the choice of lubricant for their cars given level of viscosity.
Thus, for lubricating oil are typically required with the viscosity grade of 5 or 7, depending on the class of surface treatment slip speed and bearing. Bearings operating at high loads (eg, eccentric presses) require the use of oils with the viscosity grade ISO 68 or 100; Roller bearing lubricating oil viscosity at the operating temperature should be approximately equal to 12 cSt.
Manufacture of oil > Base oils > Aircraft oils > Engine oils