How is oil refining done? Fractional composition of oil and oil products

14.06.2019

The composition of oil and its products is determined by separation according to boiling points by distillation and rectification.

Output of oil fractions

Oil, gas condensates and their fractions are a multicomponent mixture of hydrocarbon compounds. AT . Therefore, the determination of the composition of this mixture as the totality of all the compounds included in their composition is a most difficult and not always solvable task.

The cost of purchasing crude oil, accounting for about 80% of refinery costs, is the most important factor in determining profitability oil company. The quality and value of crude oil depends on its ITC curve, which determines the content of the fraction of light oil products boiling up to 360°C, the fraction 360-540°C and the bottom product (>540°C), and the content of impurities such as sulfur, nitrogen, metals etc.

However, the ITC curve does not reflect the chemical composition of oil fractions, which, in turn, affects the yield and product properties of units for the conversion and upgrading of petroleum products at refineries. Thus, knowledge of the ITC curve and chemical nature fractions of crude oil is extremely important for improving the economic performance of refineries. Unfortunately, to obtain this information, laboratory analyzes are required, which require large financial and time costs.

Main factions

hydrocarbon gas

The gas that is part of this oil consists mainly of butanes (73.9% wt.); the yield of gases into oil is 1.5% wt. Propane-butane fraction will be used as a feedstock for gas fractionation plants to produce individual hydrocarbons, fuel and a component of motor gasoline.

Fraction NK-62°C

The NK-62°С fraction will be used as a feedstock for the catalytic isomerization process in order to increase the octane number.

Fraction 62-85°С

The 62-85°C fraction is called "benzene", it will be used as a component of commercial gasoline and for the production of benzene.

Fraction 85-120°С

The 85-120°C fraction mixed with the 120-180°C fraction will be used as feedstock for a catalytic reformer to increase the octane number. Pre-sent to hydrotreatment.

Fraction 120-180°С and 180-230°С

The 120-180°C fraction will be used in mixture with the 180-230°C fraction as a jet fuel component. Jet fuel is not suitable for flash point, so you need to remove some of the light components.

Oil extraction methods

Individual composition of petroleum products

At present, the individual composition of petroleum products can be fairly reliably determined by gas-liquid chromatography methods only for single gasoline fractions. Therefore, an individual hydrocarbon composition cannot be used as the basis for predictive methods for calculating thermophysical properties (TPP) due to its unavailability for consumers.

At the same time, the fractional composition and structural-group hydrocarbon composition can be more fruitfully used in the development of methods for calculating the thermal properties of oil.

Therefore, methods for recalculating and extrapolating distillation curves and methods for calculating the structural group hydrocarbon composition of fractions are considered below.

Fractional composition of oil and oil products

This type of composition of oil and its products is determined by separation according to boiling points by distillation and rectification.

The total yield (in percent by weight or volume) of individual fractions that boil away in certain temperature ranges is called the fractional composition of oil, oil product or mixture. For more complete characteristics the relative density and average molar mass each shoulder strap and mixture as a whole. Based on the results of evaporation, an ITC curve is built, which contains fairly complete information about the composition of the mixture.

Rectification according to GOST 11011-85 in the ARN-2 apparatus is limited by a temperature of 450-460 ° C due to the possible thermal decomposition of the residue. Carrying out this type of study of oils is recommended in the ARN-2 distillation device according to the GrozNII method in a Manovyan flask up to a boiling point of 560-580 °C. In this case, there is no distortion of the ITC curve.

Fractional composition, especially light commercial petroleum products and broad fractions, are often determined by distillation in an Engler apparatus according to GOST 2177-82, which is much simpler than rectification. The Engler distillation curve makes it possible to reliably determine the characteristic boiling points of the fractions. However, when calculating phase equilibria, it is preferable to have an ITC curve. A number of empirical procedures have been proposed to obtain such a curve.

For example, for light oil products, the BashNIINP method is known. Based on the fact that the temperature difference obtained during the distillation of a commercial oil product according to the ITC and according to the Engler, at a certain point of the boiling point of the oil product is almost constant, we can write

Characterization of physical and chemical properties (PCS) of narrow oil fractions (pseudocomponents)

When calculating the processes of distillation of multicomponent mixtures (MCM), it is necessary to use the physicochemical and thermodynamic properties of all components that make up the separated MCM. Since, in the case under consideration, the decomposition of the initial continuous mixture into pseudocomponents is rather arbitrary, the procedure for calculating the physicochemical properties of individual pseudocomponents is of particular importance.

It is known that any Chemical substance has a set of characteristic constants, and the values of the characteristic constants depend on chemical structure substance molecules. This provision can also be extended to pseudocomponents, especially if the values of the characteristic constants are determined experimentally.

By the way, read this article too: Features of heavy oil processing

The arithmetic mean (between the beginning and the end of fraction boiling off) boiling point is taken as the main and minimum required characteristic of the pseudocomponent.

However, this temperature does not fully characterize the pseudo-component, since it does not take into account the compositional features of oils. various types(various deposits). For a more accurate assessment of the FCS of pseudocomponents, information on the hydrocarbon composition of the fractions is required.

This information is indirectly contained in the RI and ITC curves. Moreover, according to the mass conservation law, the averaged (average integral) values of the pseudo-characteristic constants and the probable hydrocarbon composition for the fractions isolated from the compared curves at the same consumption boiling ranges must match (with the exception of their boiling temperature limits) .

Therefore, to assess the hydrocarbon composition of motor fuels, it is quite acceptable to use the RI curve, as it is simpler and more convenient for experimental determination. However, when calculating separation processes (primarily rectification), it is necessary to use only the ITC curve.

For calculations, as pseudocharacteristic constants of all components (pseudocomponents) of the MCS, standard properties are used (boiling points, phase transition temperatures, saturated vapor pressures, densities of gas and liquid phases under standard conditions, refractive indices, viscosity, enthalpy, etc.), as well as critical properties. These constants characterize the chemical identity of the component, i.e. represent the "chemical passport" of the substance. Characteristic properties are functions of specific chemical parameters of a substance: molar mass and structure of a molecule of a substance:

It follows from (1.1) that all standard properties turn out to be interconnected and can be expressed through each other. So the molar mass of any hydrocarbon (pseudocomponent) can be expressed as a function of its standard properties: boiling point, density, refractive index and other properties, as well as a combination of these properties. As an example, we can cite the formulas of B.P. Voinov, Kreg and Mamedov for calculating the molecular weight of hydrocarbons:

Therefore, the number of options for calculating the TFS of pseudocomponents turns out to be quite large, which to a certain extent complicates their practical use.

To calculate the FCS of wide oil fractions, consisting of several pseudo-components, the additivity rule is used, i.e. the contribution of each narrow fraction to the properties of the wider fraction is determined by the relative concentration of the narrow fraction in the wider one.

By the way, read this article too: Translation kinematic viscosity into dynamic

In UMP, the procedures for calculating FCS for continuous mixtures are automated: the user, in accordance with the accepted temperature breakdown of the ITC curve into pseudo-components, sets the boiling limits of individual pseudo-components (individual narrow fractions), after which he fills in the specification for each selected pseudo-component, setting its characteristic properties known to the user.

As the minimum required information, as already mentioned, should be given average temperature the boiling point of the pseudo-component, and the properties (density, refractive index, etc.) known to the user are set as an additional one. The more fully this information is defined, the more accurately each pseudo-component will be characterized, and, therefore, the results of subsequent modeling will be more accurate. For an example in fig. 1.7 shows the distribution curves of the characteristic properties ( tWed,p,n) for straight-run hydrotreated gasoline.

Rice. 1.7. Boiling temperature distribution curves ( tWed), density ( p) and refractive index ( n) fractions of straight-run hydrotreated gasoline

In accordance with the accepted condition for a fairly smooth change in the characteristic properties with a change in the boiling point of individual components (the number of individual components is very large), the dependences of all properties on the fraction of distillation of the substance (or on the distillation temperature) should also be continuous.

Based on this information, all basic properties can be calculated ( Tkr, Pkr, Zkr, enthalpy characteristics) of both individual pseudo-components, and the mean integral values of these properties for the fraction as a whole, and also the probable gross formulas of hypothetical pseudo-components are determined. In fact, the same approach is used in the mutual recalculation of the RI and ITC curves.

At the same time, the presence of even incomplete information (only individual properties for individual fractions, even in a limited range of change in the fraction of distillate) can significantly increase the adequacy of the generalizing information. So, for the example shown in Fig. 1.4, taking into account only one property for the fraction as a whole (fuel oil density) noticeably refines the form of the final characteristic (ITC curve).

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The essence of the oil refining industry
The oil refining process can be divided into 3 main stages:
1. Separation of crude oil into fractions that differ in boiling point ranges (primary processing);
2. Processing of the obtained fractions by chemical transformations of the hydrocarbons contained in them and the development of components of marketable petroleum products (recycling);
3. Mixing of components with the involvement, if necessary, of various additives, to obtain commercial petroleum products with specified quality indicators (commodity production).
The products of the refinery are motor and boiler fuels, liquefied gases, different kinds raw materials for petrochemical industries, as well as, depending on the technological scheme of the enterprise - lubricating, hydraulic and other oils, bitumen, petroleum coke, paraffins. Based on a set of technological processes, from 5 to more than 40 positions of marketable petroleum products can be obtained at the refinery.
Oil refining - continuous production, the period of operation of production between overhauls at modern factories is up to 3 years. The functional unit of the refinery is the technological installation- a production facility with a set of equipment that allows to carry out a full cycle of a particular technological process.
This article briefly describes the main technological processes fuel production - obtaining motor and boiler fuels, as well as coke.

Delivery and reception of oil
In Russia, the main volumes of crude oil supplied for processing are delivered to refineries from producing associations via main oil pipelines. Small quantities of oil, as well as gas condensate, are supplied by railway. In oil-importing countries with access to the sea, delivery to port refineries is carried out by water transport.
Raw materials accepted at the plant enter the appropriate containers commodity base(Fig. 1), connected by pipelines with all technological units of the refinery. The amount of oil received is determined according to instrumental accounting, or by measurements in raw containers.

Preparation of oil for processing (electric desalination)
Crude oil contains salts that cause severe corrosion of process equipment. To remove them, the oil coming from the feed tanks is mixed with water, in which the salts dissolve, and enters the ELOU - electrical desalination plant(Fig. 2). The desalination process is carried out in electric dehydrators- cylindrical devices with electrodes mounted inside. Under the influence of a high voltage current (25 kV or more), the mixture of water and oil (emulsion) is destroyed, water is collected at the bottom of the apparatus and pumped out. For more effective destruction of the emulsion, special substances are introduced into the raw materials - demulsifiers. Process temperature - 100-120°C.

Primary oil refining
Desalted oil from ELOU is supplied to the atmospheric vacuum distillation unit, which at Russian refineries is abbreviated ABT - atmospheric vacuum tube. This name is due to the fact that the heating of raw materials before separating it into fractions is carried out in coils tube furnaces(Fig. 6) due to the heat of fuel combustion and the heat of flue gases.
AWT is divided into two blocks - atmospheric and vacuum distillation.

1. Atmospheric distillation
Atmospheric distillation (Fig. 3.4) is intended for selection light oil fractions- gasoline, kerosene and diesel, boiling up to 360°C, the potential yield of which is 45-60% for oil. The rest of the atmospheric distillation is fuel oil.
The process consists in separating the oil heated in the furnace into separate fractions in distillation column- a cylindrical vertical apparatus, inside which are located contact devices (plates) through which the vapor moves up and the liquid moves down. Distillation columns of various sizes and configurations are used in almost all oil refining plants, the number of plates in them varies from 20 to 60. Heat supply is provided in lower part column and heat removal from the upper part of the column, in connection with which the temperature in the apparatus gradually decreases from the bottom to the top. As a result, the gasoline fraction is removed from the top of the column in the form of vapors, and the vapors of the kerosene and diesel fractions condense in the corresponding parts of the column and are removed, the fuel oil remains liquid and is pumped out from the bottom of the column.

2. Vacuum distillation
Vacuum distillation (Fig. 3,5,6) is intended for selection from fuel oil oil distillates at refineries of the fuel-oil profile, or a wide oil fraction (vacuum gas oil) at the refinery of the fuel profile. The remainder of the vacuum distillation is tar.
The need to select oil fractions under vacuum is due to the fact that at temperatures above 380 ° C, thermal decomposition of hydrocarbons begins. (cracking), and the end of boiling vacuum gas oil - 520°C or more. Therefore, the distillation is carried out at a residual pressure of 40-60 mm Hg. Art., which allows to reduce maximum temperature in the apparatus up to 360-380°C.
The vacuum in the column is created using appropriate equipment, the key devices are steam or liquid ejectors(Fig. 7).

3. Stabilization and secondary distillation of gasoline
The gasoline fraction obtained at the atmospheric unit contains gases (mainly propane and butane) in a volume that exceeds the quality requirements and cannot be used either as a component of motor gasoline or as commercial straight-run gasoline. In addition, refinery processes aimed at increasing the octane number of gasoline and the production aromatic hydrocarbons narrow gasoline fractions are used as raw materials. This is the reason for the inclusion of this process in the technological scheme of oil refining (Fig. 4), in which liquefied gases are distilled from the gasoline fraction, and it is distilled into 2-5 narrow fractions on the corresponding number of columns.

Products of primary oil refining are cooled in heat exchangers, in which they give off heat to the cold raw material entering for processing, due to which process fuel is saved, in water and air coolers and are taken out of production. A similar heat exchange scheme is used at other refinery units.

Modern primary processing plants are often combined and may include the above processes in various configurations. The capacity of such installations is from 3 to 6 million tons of crude oil per year.
Several primary processing units are being built at the plants in order to avoid a complete shutdown of the plant when one of the units is taken out for repairs.

Products of primary oil refining

Name	Boiling intervals (compound)	Where is selected	Where is used (in order of priority)
Reflux stabilization	propane, butane, isobutane	Stabilization block	Gas fractionation, marketable products, process fuel
Stable straight-run gasoline (naphtha)		Secondary distillation of gasoline	Gasoline blending, commercial products
Stable light petrol		Stabilization block	Isomerization, gasoline blending, marketable products
benzene		Secondary distillation of gasoline	Production of corresponding aromatic hydrocarbons
Toluene		Secondary distillation of gasoline
xylene		Secondary distillation of gasoline
Catalytic Reforming Feedstock		Secondary distillation of gasoline	catalytic reforming
heavy gasoline		Secondary distillation of gasoline	Blending kerosene, winter diesel fuel, catalytic reforming
Kerosene component		atmospheric distillation	Mixing of kerosene, diesel fuels
Diesel		atmospheric distillation	Hydrotreatment, blending of diesel fuels, fuel oils
		Atmospheric distillation (residue)	Vacuum distillation, hydrocracking, fuel oil blending
Vacuum gas oil		vacuum distillation	Catalytic cracking, hydrocracking, marketable products, fuel oil blending.
		Vacuum distillation (residue)	Coking, hydrocracking, blending of fuel oils.

*) - n.c. - the beginning of the boil
**) - k.k. - end of boil

Photographs of primary processing plants of various configurations


Fig.5. Vacuum distillation unit with a capacity of 1.5 million tons per year at the Turkmenbashi refinery under the project of Uhde.	Rice. 6. Vacuum distillation unit with a capacity of 1.6 million tons per year at the LUKOIL-PNOS refinery. In the foreground is a tube furnace (yellow).	Fig.7. Vacuum generating equipment from Graham. 3 ejectors are visible, into which vapors enter from the top of the column.

Sergey Pronin

Oil fractions are determined in the laboratory, since the product contains organic substances that have different pressure saturated vapors. It is impossible to talk about the boiling point, as such, but the starting point and limit are calculated. A certain interval interval of oil boiling is +28-540°C. It determines the fractional composition of oil. It is regulated by the GOST 2177-99 standard. The temperature at which condensate appears is taken as the onset of boiling. The end of boiling is considered the moment of cessation of evaporation of vapors. Laboratory tests are carried out on distillation apparatus, where stable readings are recorded and a curve of boiling points is derived by distillation. Separation of oil and oil products into fractions up to +200°C is carried out at atmospheric pressure. The rest at higher temperatures are sampled under vacuum so that decomposition does not occur.

Methods for determining the fractional composition of petroleum products

Fractionation of oil is necessary to choose the direction of processing of the raw material base, to find out the exact content of base oils during oil distillation. Based on this, all properties of the fractions are classified.

Method A - the use of automatic devices for determining the fractional composition of oil and individual pseudo-components. Flasks are used from heat-resistant glass, the bottom and walls of which are of the same thickness.
Method B - using a four-slot or six-slot device. Flasks with a round bottom with a capacity of 250 cm3. The method is used only for distillation of dark oil products.

Types and properties of oil fractions

The fractional composition of oil is determined according to the Russian distillation or rectification standard, which corresponds to the Egler distillation. It is based on the division of the complex composition of carbohydrate gases into intermediate elements. Based on boiling high temperatures, 3 types of oil refining are classified.

Simple distillation - during evaporation, the vapor condenses.
Reflux - only high-boiling vapors emit condensate and return back to the general mixture in the form of reflux. Low-boiling vapors evaporate completely.
Rectification is the process of combining the two previous types of processing, when the maximum concentration and condensation of low-boiling vapors is reached.

In the process of determining the fractional composition of oil and oil products, as well as their properties, there is a division into the following types of fractions:

light (this type includes gasoline and petroleum) - they come out at temperatures up to 140 ° C at atmospheric pressure;
medium (this includes: kerosene, diesel, naphtha) at atmospheric pressure in the temperature range of 140-350°C;
at vacuum processing and temperatures above 350 ° C, fractions are obtained, which are called heavy (Vacuum gas oil, tar).

Fractions are also divided into light (this includes light and medium) and dark or fuel oil (these are heavy fractions).

Oil fractions table

And now more about the main types of oil fractions:

Petroleum fraction

Ether or Sherwood oil is a colorless liquid that is composed of pentane and hexane. Evaporates immediately at low temperatures. It is a solvent for creating extracts, fuel for lighters, burners. It is obtained at temperatures up to + 100°C.

Gasoline fraction

The gasoline fraction of oil is built on a complex scheme of carbon compounds that boil away at a temperature of + 140°C. The main application is used to obtain fuel for internal combustion engines and as a raw material in petrochemicals. The gasoline fraction is based on paraffinic substances: methylcyclopentane, cyclohexane, methylcyclohexane. Gasoline contains liquid alkanes in composition - natural, associated, gaseous. They are also divided into branched and unbranched. The composition depends on the qualitative ratio of the components of the raw material. This suggests that good gasoline is far from being obtained from all grades of oil. The value of the species is that in the process of decomposition into compounds, aromatic hydrocarbons are formed, the share of which in the raw mass is catastrophically small.

Naphtha fraction

The subspecies includes heavy elements. The saturation with aromatic hydrocarbons is greater than that of other compounds. It is a component for the production of commercial gasoline, lighting kerosene, jet fuel, an organic solvent. Acts as a filler household appliances. Chemical composition: polycyclic, cyclic and unsaturated hydrocarbons. The presence of sulfur differs, the percentage of total mass which depends on the deposit, the level of occurrence and the quality of the raw product.

Kerosene fraction

The kerosene fraction of oil is primarily a fuel for jet engines. It is used in the manufacture of paints and varnishes and is added as a solvent to paint for walls and floors. Acts as a raw material in the processes of synthesis of substances. Compounds of carbohydrates with a high content of paraffin. There is a low content of aromatic carbohydrates. The kerosene fraction is released during atmospheric distillation within + 220°C.

Diesel fraction

The subspecies is used in the manufacture of diesel fuel for high-speed modes of transport, and is also used as a secondary raw material. In the process of processing, kerosene is released, which is used for the paint and varnish industry and instrument making, the manufacture of chemicals for vehicles. The predominance of mixtures of naphthene hydrocarbons. To obtain fuel that does not solidify at -60°C, the composition undergoes carbamide dewaxing. This is mixing of all components for 1 hour and subsequent filtration through a Buchner funnel.

fuel oil

The qualitative composition of the mixture: resin oils, organic compounds with trace elements. Hydrocarbon components: asphaltene, carbene, carboid. During vacuum distillation, tar, paraffin, technical oils are produced from fuel oil. The main application is liquid fuel for boilers for its viscosity characteristics. Furnace fuel oil is divided into 3 main types: naval, medium-boiler and heavy. The latter is used in CHP, middle view- in boiler plants. Naval - an integral part of the work of shipping transport.

Tar

The quality of the components as a percentage is determined as follows:

Paraffin, naphthene - 95%.
Asphalten - 3%.
Resins - 2%.

Vacuum tar is obtained as a result of the completion of all separation and distillation processes. Boiling point + 500°С. The output is a viscous black consistency. The liquid composition is used in road construction. Bitumen for roofing materials is produced from it. Tar is needed to create coke - a product strategic purpose. The component is used in the manufacture of boiler fuel. It contains the largest percentage heavy metals contained in oil.

Raw indicators of oil products depend on the depth and type of deposit. This is taken into account when forming oil fractions and achieving the percentage ratio of components.

Rectification is a process of separation of binary or multicomponent mixtures due to countercurrent mass and heat exchange between vapor and liquid.

Rectification of oil consists in separation into fractions when heated, while fractions differing in boiling point are separated. Low-boiling fractions are called light, and high-boiling fractions are called heavy.

As a result of the rectification of oil, gasoline, kerosene, diesel fuel, oils and other fractions are obtained.

Light oil products - gasoline, kerosene and diesel fuel are obtained at installations called atmospheric or atmospheric tubes (AT), since the process takes place under atmospheric pressure, and the oil is heated in a tube furnace. The residue obtained at these plants - fuel oil - can be sent to a vacuum plant, where, as a result of distillation, various grades of lubricating oils are obtained.

Distillation with distillation is the most common mass transfer process in chemical and oil and gas technology, carried out in apparatuses - distillation columns - by repeated countercurrent contacting of vapors and liquids.

The main fractions isolated during the primary distillation of oil:

21 . Production of hydrogen from methane.

Steam reforming of natural gas/methane

Steam reforming- production of pure hydrogen from light hydrocarbons (for example, methane, propane-butane fraction) by steam reforming (catalytic conversion of hydrocarbons in the presence of steam).

CH 4 + H 2 O \u003d CO + 3H 2 - steam reforming reaction;

Hydrogen can be obtained in different purity: 95-98% or extra pure. Depending on the further use, hydrogen is obtained under different pressures: from 1.0 to 4.2 MPa. The raw material (natural gas or light oil fractions) is heated up to 350-400°C in a convection oven or heat exchanger and enters the desulfurization apparatus. The converted gas from the furnace is cooled in the recovery furnace, where steam of the required parameters is produced. After the stages of high-temperature and low-temperature conversion of CO, the gas is fed to the adsorption of CO 2 and then to the methanation of residual oxides. The result is hydrogen of 95-98.5% purity containing 1-5% methane and traces of CO and CO 2 .

In the event that it is required to obtain highly pure hydrogen, the unit is supplemented with a section for the adsorption separation of the converted gas. In contrast to the previous scheme, CO conversion here is single-stage. Gas mixture containing H 2 , CO 2 , CH 4 , H 2 O and not a large number of CO is cooled to remove water and sent to adsorption apparatuses filled with zeolites. All impurities are adsorbed in one stage at ambient temperature. The result is hydrogen with a purity of 99.99%. The pressure of the resulting hydrogen is 1.5-2.0 MPa.

Oil refining is a rather complicated process, which requires involvement. Many products are obtained from the extracted natural raw materials - different types fuels, bitumen, kerosene, solvents, lubricants, petroleum oils and others. Oil refining begins with the transportation of hydrocarbons to the plant. Manufacturing process takes place in several stages, each of which is very important from a technological point of view.

Recycling process

The process of oil refining begins with its specialized preparation. This is due to the presence of numerous impurities in natural raw materials. An oil deposit contains sand, salts, water, soil, and gaseous particles. Water is used to extract a large number of products and save energy deposits. This has its advantages, but significantly reduces the quality of the resulting material.

The presence of impurities in the composition of petroleum products makes it impossible to transport them to the plant. They provoke the formation of plaque on heat exchangers and other containers, which significantly reduces their service life.

Therefore, the extracted materials are subjected to complex cleaning - mechanical and fine. At this stage of the production process, the resulting raw material is separated into oil and. This happens with the help of special oil separators.

To purify the raw material, it is mainly settled in hermetic tanks. To activate the separation process, the material is exposed to cold or high temperature. Electric desalination plants are used to remove salts contained in raw materials.

How does the process of separating oil and water take place?

After primary purification, a sparingly soluble emulsion is obtained. It is a mixture in which particles of one liquid are evenly distributed in the second. On this basis, 2 types of emulsions are distinguished:

hydrophilic. It is a mixture where oil particles are in water;
hydrophobic. The emulsion mainly consists of oil, where there are particles of water.

The process of breaking the emulsion can be mechanical, electrical or by chemical means. The first method involves settling the liquid. This happens under certain conditions - heating to a temperature of 120-160 degrees, increasing the pressure to 8-15 atmospheres. The stratification of the mixture usually occurs within 2-3 hours.

In order for the process of separation of the emulsion to be successful, it is necessary to prevent the evaporation of water. Also, the extraction of pure oil is carried out using powerful centrifuges. The emulsion is divided into fractions when reaching 3.5-50 thousand revolutions per minute.

The use of a chemical method involves the use of special surfactants called demulsifiers. They help to dissolve the adsorption film, as a result of which the oil is cleaned of water particles. The chemical method is often used in conjunction with the electrical method. The last cleaning method involves exposing the emulsion to an electric current. It provokes the association of water particles. As a result, it is more easily removed from the mixture, resulting in the highest quality oil.

Primary processing

Extraction and processing of oil takes place in several stages. A feature of the production of various products from natural raw materials is that even after high-quality purification, the resulting product cannot be used for its intended purpose.

The starting material is characterized by the content of various hydrocarbons, which differ significantly in molecular weight and boiling point. It contains substances of naphthenic, aromatic, paraffinic nature. Also, the feedstock contains sulfur, nitrogen and oxygen compounds of the organic type, which must also be removed.

All existing ways oil refining is aimed at dividing it into groups. During the production process, wide range products with different characteristics.

Primary processing of natural raw materials is carried out on the basis of different temperatures boiling of its constituent parts. For the implementation of this process, specialized installations are involved, which make it possible to obtain various oil products - from fuel oil to tar.

If natural raw materials are processed in this way, it will not be possible to obtain a material ready for further use. Primary distillation is aimed only at determining the physical and chemical properties of oil. After it is carried out, it is possible to determine the need for further processing. They also set the type of equipment that needs to be involved to perform the necessary processes.

Primary oil refining

Oil distillation methods

There are the following methods of oil refining (distillation):

single evaporation;
repeated evaporation;
distillation with gradual evaporation.

The flash method involves the processing of oil under the influence of a high temperature with a given value. As a result, vapors are formed that enter a special apparatus. It is called an evaporator. AT this device cylindrical pairs are separated from the liquid fraction.

With repeated evaporation, the raw material is subjected to processing, in which the temperature is increased several times according to a given algorithm. The last distillation method is more complex. Processing of oil with gradual evaporation implies a smooth change in the main operating parameters.

Distillation equipment

Industrial oil refining is carried out using several devices.

Tube furnaces. In turn, they are also divided into several types. These are atmospheric, vacuum, atmospheric-vacuum furnaces. With the help of equipment of the first type, shallow processing of petroleum products is carried out, which makes it possible to obtain fuel oil, gasoline, kerosene and diesel fractions. In vacuum furnaces, as a result of more effective work raw materials are divided into:

tar;
oil particles;
gas oil particles.

The resulting products are fully suitable for the production of coke, bitumen, lubricants.

distillation columns. The process of processing crude oil using this equipment involves heating it in a coil to a temperature of 320 degrees. After that, the mixture enters the intermediate levels of the distillation column. On average, it has 30-60 chutes, each spaced at a certain interval and equipped with a liquid bath. Due to this, the vapors flow down in the form of droplets, as condensation forms.

There is also processing using heat exchangers.

Recycling

After determining the properties of the oil, depending on the need for a particular final product, the type of secondary distillation is selected. Basically, it consists in a thermal-catalytic effect on the feedstock. Deep processing of oil can occur using several methods.

Fuel. Application this method secondary distillation makes it possible to obtain a number of high-quality products - motor gasoline, diesel, jet, boiler fuels. Recycling does not require a lot of equipment. As a result of the application this method the finished product is obtained from the heavy fractions of raw materials and sediment. The fuel distillation method includes:

cracking;
reforming;
hydrotreating;
hydrocracking.

Fuel oil. As a result of this distillation method, not only various fuels are obtained, but also asphalt, lubricating oils. This is done using the extraction method, deasphalting.

Petrochemical. As a result of applying this method with the involvement of high-tech equipment, a large number of products are obtained. This is not only fuel, oils, but also plastics, rubber, fertilizers, acetone, alcohol and much more.

How objects around us are obtained from oil and gas - accessible and understandable

This method is considered the most common. With its help, the processing of sour or sour oil is carried out. Hydrotreating can significantly improve the quality of the resulting fuels. Various additives are removed from them - sulfur, nitrogen, oxygen compounds. The material is processed on special catalysts in a hydrogen environment. At the same time, the temperature in the equipment reaches 300-400 degrees, and the pressure - 2-4 MPa.

As a result of distillation, organic compounds contained in raw materials decompose when interacting with hydrogen circulating inside the apparatus. As a result, ammonia and hydrogen sulfide are formed, which are removed from the catalyst. Hydrotreating makes it possible to recycle 95-99% of raw materials.

catalytic cracking

Distillation is carried out using zeolite-containing catalysts at a temperature of 550 degrees. Cracking is considered to be a very efficient method of processing prepared raw materials. With its help, high-octane motor gasoline can be obtained from fuel oil fractions. The yield of pure product in this case is 40-60%. Liquid gas is also obtained (10-15% of the original volume).

catalytic reforming

Reforming is carried out using an aluminum-platinum catalyst at a temperature of 500 degrees and a pressure of 1-4 MPa. At the same time, a hydrogen environment is present inside the equipment. This method is used to convert naphthenic and paraffinic hydrocarbons to aromatics. This allows you to significantly increase the octane number of products. When using catalytic reforming, the yield of pure material is 73-90% of the feedstock.

Hydrocracking

Allows you to get liquid fuel when exposed to high pressure(280 atmospheres) and temperature (450 degrees). Also, this process occurs with the use of strong catalysts - molybdenum oxides.

If hydrocracking is combined with other methods of processing natural raw materials, the yield of pure products in the form of gasoline and jet fuel is 75-80%. When using high-quality catalysts, their regeneration may not be carried out for 2-3 years.

Extraction and deasphalting

Extraction involves the separation of the prepared raw materials into the desired fractions using solvents. Subsequently, deparaffinization is carried out. It allows you to significantly reduce the pour point of the oil. Also for products High Quality it is hydrotreated. As a result of the extraction, distilled diesel fuel can be obtained. Also, using this technique, aromatic hydrocarbons are extracted from the prepared raw materials.

Deasphalting is necessary in order to obtain resinous-asphaltene compounds from the end products of the distillation of petroleum feedstock. The resulting substances are actively used for the production of bitumen, as catalysts for other processing methods.

Other processing methods

Processing of natural raw materials after primary distillation can be carried out in other ways.

Alkylation. After processing the prepared materials, high-quality components for gasoline are obtained. The method is based on the chemical interaction of olefinic and paraffinic hydrocarbons, resulting in a high-boiling paraffinic hydrocarbon.

Isomerization. The use of this method makes it possible to obtain a substance with a higher octane number from low-octane paraffinic hydrocarbons.

Polymerization. Allows the conversion of butylenes and propylene into oligomeric compounds. As a result, materials are obtained for the production of gasoline and for various petrochemical processes.

Coking. It is used for the production of petroleum coke from heavy fractions obtained after the distillation of oil.

The oil refining industry is a promising and developing one. The production process is constantly being improved through the introduction of new equipment and techniques.