The main technological processes of fuel production. Refining in brief

Oil is a mineral, which is a water-insoluble oily liquid that can be either almost colorless or dark brown. The properties and methods of oil refining depend on the percentage ratio of predominantly hydrocarbons in its composition, which differs in different fields.

So, in the Sosninskoye field (Siberia) alkanes (paraffin group) account for 52 percent, cycloalkanes - about 36%, aromatic hydrocarbons - 12 percent. And, for example, in the Romashkino field (Tatarstan) the share of alkanes and aromatic carbons is higher - 55 and 18 percent, respectively, while cycloalkanes have a share of 25 percent. In addition to hydrocarbons, this feedstock may include sulfur, nitrogen compounds, mineral impurities, etc.

For the first time oil was "refined" in 1745 in Russia

This natural fossil is not used in its raw form. To obtain technically valuable products (solvents, motor fuel, components for chemical production), oil is refined using primary or secondary methods. Attempts to transform these raw materials were made as early as the middle of the eighteenth century, when, in addition to candles and torches used by the population, "burning oil" was used in the lamps of a number of churches, which was a mixture of vegetable oil and refined oil.

Oil refining options

Refining is often not included directly in oil refining processes. Rather, it is a preliminary stage, which may consist of:

Chemical cleaning, when oil is exposed to oleum and concentrated sulfuric acid. This removes aromatic and unsaturated hydrocarbons.

Adsorption cleaning. Here, resins and acids can be removed from oil products by treatment with hot air or by passing oil through an adsorbent.

Catalytic cleaning - mild hydrogenation to remove nitrogenous and sulfur compounds.

Physical and chemical cleaning. In this case, excess constituents are selectively isolated by means of solvents. For example, the polar solvent phenol is used to remove nitrogenous and sulfur compounds, while non-polar solvents - butane and propane - release tar, aromatic hydrocarbons, etc.

No chemical changes ...

Oil refining through primary processes does not involve chemical transformations of the feedstock. Here, the mineral is simply separated into its constituent components. The first oil distillation device was invented in 1823, in the Russian Empire. The Dubinin brothers guessed to put the boiler into a heated furnace, from where a pipe went through a barrel with cold water into an empty container. In the furnace boiler the oil was heated, passed through the "refrigerator" and settled.

Modern methods of preparing raw materials

Today, at oil refining complexes, oil refining technology begins with additional purification, during which the product is dehydrated on ELOU devices (electrical desalting plants), freed from mechanical impurities and light carbohydrates (C1 - C4). Then the raw material can go to atmospheric distillation or vacuum distillation. In the first case, the factory equipment, according to the principle of operation, resembles that which was used back in 1823.

Only the oil refining unit itself looks different. The company has furnaces that are the size of houses without windows, made of the finest refractory bricks. Inside them are many kilometers of pipes, in which oil moves at a high speed (2 meters per second) and is heated up to 300-325 C with a flame from a large nozzle (at higher temperatures, hydrocarbons simply decompose). The pipe for condensation and cooling of vapors today is replaced by rectification columns (can be up to 40 meters in height), where vapors are separated and condensed, and whole townships from different reservoirs are built to receive the resulting products.

What is material balance?

Oil refining in Russia gives different material balances during the atmospheric distillation of raw materials from a particular field. This means that the output can be different proportions for different fractions - gasoline, kerosene, diesel, fuel oil, associated gas.

For example, for West Siberian oil, gas yield and losses are one percent each, respectively, gasoline fractions (released at temperatures from about 62 to 180 C) occupy about 19%, kerosene - about 9.5%, diesel fraction - 19% , fuel oil - almost 50 percent (released at temperatures from 240 to 350 degrees). The resulting materials are almost always subjected to additional processing, since they do not meet the operational requirements for the same machine motors.

Production with less waste

Vacuum processing of oil is based on the principle of boiling substances at a lower temperature with a decrease in pressure. For example, some hydrocarbons in oil boil only at 450 ° C (atmospheric pressure), but they can be made to boil at 325 ° C if the pressure is reduced. Vacuum processing of raw materials is carried out in rotary vacuum evaporators, which increase the distillation rate and make it possible to obtain ceresins, paraffins, fuel, oils from fuel oil, and use the heavy residue (tar) further for the production of bitumen. Vacuum distillation produces less waste than atmospheric distillation.

Recycling allows you to get high-quality gasoline

The secondary oil refining process was invented in order to obtain more motor fuel from the same feedstock by acting on the molecules of petroleum hydrocarbons, which acquire formulas more suitable for oxidation. Recycling includes different types of so-called "cracking", including hydrocracking, thermal and catalytic options. This process was also originally invented in Russia, in 1891, by engineer V. Shukhov. It is the cleavage of hydrocarbons into forms with fewer carbon atoms per molecule.

Refining oil and gas at 600 degrees Celsius

The principle of operation of cracking plants is approximately the same as for installations. atmospheric pressure vacuum production. But here the processing of raw materials, which is most often represented by fuel oil, is carried out at temperatures close to 600 C. Under this influence, the hydrocarbons that make up the fuel oil mass break down into smaller ones, of which the same kerosene or gasoline consists. Thermal cracking is based on processing at high temperatures and produces gasoline with a large amount of impurities, catalytic cracking also on thermal processing, but with the addition of catalysts (for example, special clay dust), which allows you to get more gasoline of good quality.

Hydrocracking: basic types

Oil production and refining today can include various types of hydrocracking, which is a combination of hydrotreating processes, the splitting of large hydrocarbon molecules into smaller ones and the saturation of unsaturated hydrocarbons with hydrogen. Hydrocracking can be light (pressure 5 MPa, temperature about 400 C, one reactor is used, mainly diesel fuel and material for catalytic cracking) and hard (pressure 10 MPa, temperature about 400 C, several reactors, diesel, gasoline and kerosene faction). Catalytic hydrocracking allows the production of a number of oils with high viscosity coefficients and low content of aromatic and sulfurous hydrocarbons.

Refining of oil, in addition, can use the following technological processes:

Visbreaking. In this case, at temperatures up to 500 C and pressures ranging from half to three MPa, secondary asphaltenes, hydrocarbon gases, and gasoline are obtained from the raw material due to the splitting of paraffins and naphthenes.

Coking of heavy oil residues is a deep processing of oil, when the feedstock is processed at temperatures close to 500 C under a pressure of 0.65 MPa to obtain gas oil components and petroleum coke. The stages of the process end with the production of a "coke cake", which is preceded (in reverse order) by densification, polycondensation, aromatization, cyclization, dehydrogenation and cracking. In addition, the product is also subject to drying and calcination.

Reforming. This method of processing petroleum products was invented in Russia in 1911 by engineer N. Zelinsky. Today, catalytic reforming is used to obtain high-quality aromatic hydrocarbons and gasolines from naphtha and gasoline fractions, as well as hydrogen-containing gas for further processing in hydrocracking.

Isomerization. Refining of oil and gas in this case involves obtaining an isomer from a chemical compound due to changes in the carbon skeleton of the substance. Thus, high-octane components are isolated from low-octane oil components to obtain commercial gasolines.

Alkylation. This process is based on the incorporation of alkyl substituents into the organic molecule. Thus, from hydrocarbon gases of unsaturated nature, components for high-octane gasolines are obtained.

Striving for European standards

Oil and gas processing technology at refineries is constantly being improved. So, at domestic enterprises, an increase in the efficiency of processing of raw materials was noted in terms of: depth of processing, an increase in the selection of light oil products, a decrease in irrecoverable losses, etc. The plans of factories for the 10-20s of the twenty-first century include a further increase in the depth of processing (up to 88 percent) , improving the quality of manufactured products to European standards, reducing the technogenic impact on the environment.

The Russian Federation is one of the world leaders in oil extraction and production. There are more than 50 enterprises operating in the state, the main tasks of which are oil refining and petrochemicals. Among them are Kirishi NOS, Omsk Oil Refinery, Lukoil-NORSI, RNK, YaroslavNOS and so on.

On this moment most of them are linked to well-known oil and gas companies such as Rosneft, Lukoil, Gazprom and Surgutneftegaz. The period of operation of such a production is about 3 years.

Basic refined products- this is gasoline, kerosene and diesel fuel. Now more than 90% of all mined black gold is used to obtain fuel: aviation, jet, diesel, furnace, boiler, - as well as lubricating oils and raw materials for future chemical processing.

Refining technology

Refining technology consists of several stages:

separation of products into fractions that differ in boiling point;

processing of these associations using chemical compounds and the production of commercial petroleum products;

mixing of components using a variety of mixtures.

The department of science, which is dedicated to the processing of combustible minerals, is petrochemistry. She studies the processes of obtaining products from black gold and the final chemical workings. These include alcohol, aldehyde, ammonia, hydrogen, acid, ketone, and the like. Today, only 10% of the oil produced is used as feedstock for the petrochemical industry.

Basic oil refining processes

Refining processes are divided into primary and secondary. The former do not imply a chemical change in black gold, but provide for its physical separation into fractions. The second task is to increase the volume of fuel produced. They facilitate the chemical transformation of hydrocarbon molecules, which is part of oil, into simpler compounds.

Primary processes take place in three stages. Beginner is the preparation of black gold. It undergoes additional cleaning from mechanical impurities, elimination of light gases and water is carried out using modern electrical desalting equipment.

This is followed by atmospheric distillation. Oil is transferred to a distillation column, where it is divided into fractions: gasoline, kerosene, diesel and finally into fuel oil. The quality of the products at this stage of processing does not correspond to the commercial characteristics, therefore the fractions are subjected to secondary processing.

Secondary processes can be divided into several types:

deepening (catalytic and thermal cracking, visbreaking, slow coking, hydrocracking, bitumen production, etc.);

refining (reforming, hydrotreating, isomerization, and the like);

other operations for the production of oil and aromatic hydrocarbons, and alkylation.

Reforming is used for the gasoline fraction. As a result, it is saturated with aromatic mixtures. The recovered raw material is used as an element for the production of gasoline.

Catalytic cracking is used to break down heavy gas molecules, which are then used to release fuel.

Hydrocracking is a method of breaking down gas molecules in excess of hydrogen. As a result of this process, diesel fuel and elements for gasoline are obtained.

Coking is an operation for the extraction of petroleum coke from the heavy fraction and residues from the secondary process.

Hydrocracking, hydrogenation, hydrotreating, hydrodearomatization, hydrodewaxing - these are all hydrogenation processes in oil refining. Their distinctive characteristic is to carry out catalytic conversions with the presence of hydrogen or a gas that contains water.

Modern installations for primary industrial oil refining are often combined and can perform some secondary processes in various volumes.

Oil refining equipment

Oil refining equipment is:

generators;

reservoirs;

filters;

heaters for liquid and gas;

incinerators (devices for thermal waste disposal);

flare systems;

gas compressors;

steam turbines;

heat exchangers;

hydraulic testing stands for pipelines;

pipes;

fittings and the like.

In addition, the enterprises use technological furnaces for oil refining. They are designed to heat the process medium using the heat released during fuel combustion.

There are two types of these units: tube furnaces and devices for the incineration of liquid, solid and gaseous production residues.

The basics of oil refining are that, first of all, production begins with the distillation of oil and its formation into separate fractions.

Then the main part of the obtained compounds is converted into more needed products by changing their physical characteristics and the structure of molecules under the influence of cracking, reforming and other operations that are related to secondary processes. Further, petroleum products undergo sequentially different types of purification and separation.

Large refineries are involved in fractionating, converting, processing and blending black gold with lubricants. In addition, they produce heavy fuel oil and asphalt, and can also carry out further distillation of petroleum products.

Refinery design and construction

To begin with, it is necessary to design and build an oil refinery. This is a rather complicated and responsible process.

The design and construction of an oil refinery takes place in several stages:

formation of the main goals and objectives of the enterprise and investment analysis;

selection of a territory for production and obtaining permission to build a plant;

the project itself of the oil refining complex;

collection of the necessary devices and mechanisms, construction and installation, as well as commissioning;

the final stage is the commissioning of the oil producing enterprise.

The production of black gold products is carried out using specialized mechanisms.

Modern oil refining technologies at the exhibition

The oil and gas industry is widely developed in the territory Russian Federation... Therefore, the question arises about the creation of new industries and the improvement and modernization of technical equipment. In order to bring the Russian oil and gas industry to a new, higher level, an annual exhibition is held scientific advances in this area "Neftegaz".

Exposition "Oil and Gas" will be distinguished by its scale and a large number of invited companies. Among them are not only popular domestic firms, but also representatives of other states. They will demonstrate their achievements, innovative technologies, fresh business projects and the like.

In addition, the exhibition will feature oil refining products, alternative fuels and energy, modern equipment for enterprises, and so on.

Within the framework of the event, it is planned to hold a variety of conferences, seminars, presentations, discussions, master classes, lectures and discussions.

Read our other articles.

Introduction

I. Primary oil refining

1. Secondary distillation of gasoline and diesel fractions

1.1 Secondary distillation of gasoline fraction

1.2 Secondary distillation of the diesel fraction

II. Thermal processes of oil refining technologies

2. Theoretical foundations of control over the processes of delayed coking and coking in the coolant layer

2.1 Delayed coking processes

2.2 Coking in the coolant layer

III. Thermocatalytic and thermohydrocatalytic processes technology

oil refining

3. Hydrotreating of kerosene fractions

IV. Gas processing technologies

4. Refinery gases processing - absorption-gas fractionation units (AGFU) and gas fractionation (GFC) units

4.1 Gas fractionation plants (HFCs)

4.2 Absorption and gas fractionation plants (AGFU)

Conclusion

Bibliography

Introduction

The oil industry today is a large national economic complex that lives and develops according to its own laws. What does oil mean today for the national economy of the country? These are: raw materials for petrochemicals in the production of synthetic rubber, alcohols, polyethylene, polypropylene, a wide range of various plastics and finished products from them, artificial fabrics; a source for the production of motor fuels (gasoline, kerosene, diesel and jet fuels), oils and lubricants, as well as boiler and furnace fuel (fuel oil), building materials(bitumen, tar, asphalt); raw materials for obtaining a number of protein preparations used as additives in livestock feed to stimulate its growth.

Currently, the oil industry of the Russian Federation ranks third in the world. The oil complex of Russia includes 148 thousand oil wells, 48.3 thousand km of main oil pipelines, 28 refineries with a total capacity of more than 300 million tons / year of oil, as well as a large number of other production facilities.

The enterprises of the oil industry and the branches serving it employ about 900 thousand workers, including in the field of science and scientific service- about 20 thousand people.

Industrial organic chemistry has passed a long and difficult path of development, during which its raw material base has changed dramatically. Starting with the processing of plant and animal raw materials, it then transformed into coal or coke chemistry (utilizing waste from coal coking), in order to eventually turn into a modern petrochemistry, which has long been no longer content with oil refining waste. For the successful and independent functioning of its main industry - heavy, that is, large-scale, organic synthesis, a pyrolysis process was developed, around which modern olefinic petrochemical complexes are based. Basically, they receive and then process lower olefins and diolefins. The feedstock base for pyrolysis can vary from associated gases to naphtha, gas oil and even crude oil. Originally intended only for the production of ethylene, the process is now also a large-scale supplier of propylene, butadiene, benzene and other products.

Oil is our national wealth, the source of the country's power, the foundation of its economy.

technology processing oil gas

I... Primary oil refining

1. Secondary distillation of gasoline and diesel fractions

Secondary distillation - separation of fractions obtained during primary distillation into narrower shoulder straps, each of which is then used for its own purpose.

At the refinery, secondary distillation is carried out with a wide gasoline fraction, a diesel fraction (when receiving raw materials for an adsorption paraffin extraction unit), oil fractions, etc. The process is carried out in separate installations or units that are part of the AT and AVT installations.

Distillation of oil - the process of separating it into fractions according to boiling points (hence the term "fractionation") - is the basis of oil refining and obtaining at the same time motor fuel, lubricating oils and various other valuable chemical products. Primary distillation of oil is the first stage in the study of its chemical composition.

The main fractions released during the primary distillation of oil:

1. Gasoline fraction- oil strand with a boiling point from n.to. (the beginning of boiling, individual for each oil) up to 150-205 0 С (depending on the technological purpose of obtaining auto, aviation, or other special gasoline).

This fraction is a mixture of alkanes, naphthenes and aromatic hydrocarbons. All of these hydrocarbons contain from 5 to 10 C atoms.

2. Kerosene fraction- oil cut with a boiling point from 150-180 0 С to 270-280 0 С. This fraction contains С10-С15 hydrocarbons.

It is used as a motor fuel (tractor kerosene, a component of diesel fuel), for domestic needs (lighting kerosene), etc.

3. Gas oil fraction- boiling point from 270-280 0 С to 320-350 0 С. This fraction contains С14-С20 hydrocarbons. Used as diesel fuel.

4. Fuel oil- the residue after distillation of the above listed fractions with a boiling point above 320-350 0 С.

Fuel oil can be used as a boiler fuel, or undergo further processing - either distillation under reduced pressure (in vacuum) with the selection of oil fractions or a wide fraction of vacuum gas oil (in turn, serving as a feedstock for catalytic cracking in order to obtain a high-octane gasoline component), or cracking.

5. Tar- almost solid residue after distillation of oil fractions from fuel oil. From it, so-called residual oils and bitumen are obtained, from which asphalt is obtained by oxidation, which is used in the construction of roads, etc. From tar and other residues of secondary origin, coke can be obtained by coking, which is used in the metallurgical industry.

1 .1 Secondary distillation of gasoline fraction

Secondary distillation of gasoline distillate is either an independent process, or is part of a combined unit that is part of an oil refinery. In modern factories, gasoline distillate secondary distillation units are designed to obtain narrow fractions from it. These fractions are further used as feedstock for catalytic reforming, a process that produces individual aromatic hydrocarbons - benzene, toluene, xylenes, or gasoline with a higher octane number. In the production of aromatic hydrocarbons, the initial gasoline distillate is separated into fractions with boiling points: 62-85 ° C (benzene), 85-115 (120) ° C (toluene) and 115 (120) -140 ° C (xylene).

Gasoline fraction is used to obtain various types of motor fuel. It is a mixture of various hydrocarbons, including unbranched and branched alkanes. The combustion characteristics of unbranched alkanes are not ideally suited to internal combustion engines. Therefore, the gasoline fraction is often subjected to thermal reforming in order to convert unbranched molecules into branched ones. Before use, this fraction is usually mixed with branched alkanes, cycloalkanes and aromatics obtained from other fractions by catalytic cracking or reforming.

The quality of gasoline as a vehicle fuel is determined by its octane rating. It indicates the percentage by volume of 2,2,4-trimethylpentane (isooctane) in a mixture of 2,2,4-trimethylpentane and heptane (straight chain alkane) that has the same knock combustion characteristics as the gasoline tested.

Poor motor fuel has a zero octane number, and a good fuel-octane number is 100. The octane number of gasoline fraction obtained from crude oil usually does not exceed 60. The combustion characteristics of gasoline are improved by the addition of an antiknock additive, which is used as tetraethyl lead (IV) , Pb (C 2 H 5) 4. Tetraethyl lead is a colorless liquid that is obtained by heating chloroethane with an alloy of sodium and lead:

When gasoline containing this additive burns, lead and lead (II) oxide particles are formed. They slow down certain stages of the combustion of gasoline fuel and thereby prevent its detonation. Together with tetraethyl lead, more 1,2-dibromoethane is added to gasoline. It reacts with lead and lead (II) to form lead (II) bromide. Since lead (II) bromide is a volatile compound, it is removed from the car engine with the exhaust fumes. Gasoline distillate of a wide fractional composition, for example, from the boiling point to 180 ° C, is pumped through the heat exchangers and fed to the first coil of the furnace, and then to the distillation column. The top product of this column is the n-fraction. K. - 85 ° C, passing through the air cooler and refrigerator, enters the receiver. Part of the condensate is pumped as reflux to the top of the column, and the rest is fed to another column. Heat is supplied to the bottom of the column by circulating reflux (fraction 85-180 ° C), which is pumped through the second coil of the furnace and fed to the bottom of the column. The remainder from the bottom of the column is pumped to another column.

Leaving from the top of the column, vapors of the head fraction (n. To. - 62 ° C) are condensed in the air cooler; condensate, cooled in a water cooler, is collected in a receiver. From here the condensate is pumped into the tank, and part of the fraction serves as reflux for the column. The residual product - fraction 62-85 ° C - at the bottom of the column is pumped through the heat exchanger and coolers into the tank. As the upper product of the column, a fraction of 85-120 ° C is obtained, which, after passing through the apparatus, enters the receiver. Part of the condensate is returned to the top of the column as reflux, and its balance amount is removed from the installation by a pump to the tank.

Crude oil is the term used to refer to unprocessed oil - the raw material that comes out of the ground as it is. Thus, crude oil is a fossil fuel, which means that it is produced naturally from decaying plants and animals that inhabit ancient seas millions of years ago - most of the places where oil is most often found were once the bottom of the seas. Crude oil varies depending on the field and varies in color and consistency: from bright black (wet asphalt) and very viscous, to slightly transparent and almost hard.

The main value and benefit of oil is that it is the starting point for so many different substances, as it contains hydrocarbons. Hydrocarbons are molecules that apparently contain hydrogen and carbon, and differ from each other only in that they can be of different lengths and structures - from straight chains to branched chains with rings.

There are two things that make hydrocarbons interesting to chemists:

Hydrocarbons contain a lot of potential energy. Much of what is obtained from crude oil, such as gasoline, diesel, paraffin, etc. - is valuable precisely by this potential energy.
Hydrocarbons can take many different forms. The smallest hydrocarbon (in terms of number of atoms) is methane (CH 4), which is a gas that is lighter than air. Longer chains with 5 or more carbon atoms are overwhelmingly liquid. And very long chains are hard, for example, wax or resin. By the chemical structure of the "crosslinking" of hydrocarbon chains, you can get everything: from synthetic rubber to nylon and plastic. Hydrocarbon chains are actually very versatile!

The main classes of hydrocarbons in crude oil include:

Paraffin with the general formula C n H 2n + 2 (n is an integer, usually from 1 to 20) with a straight structure or a branched chain can represent gases or liquids that already boil at room temperature, depending on the examples of molecules: methane, ethane, propane, butane, isobutane, pentane, hexane.
Aromatics with the general formula: C 6 H 5 -Y (Y is a large, straight molecule that connects to the benzene ring) are ring-like structures with one or more rings that contain six carbon atoms, with alternating double simple bonds between carbon atoms. Notable examples of aromatics are benzene and naphthalene.
Naphthenes or cycloalkanes with the general formula C n H 2n (n is an integer, usually from 1 to 20) are ring-like structures with one or more rings that contain only simple bonds between carbon atoms. These are, as a rule, liquids: cyclohexane, methylcyclopentane and others.
Alkenes with the general formula C n H 2n (n is an integer, usually from 1 to 20) are linear or branched chain molecules containing one carbon-carbon double bond, which can be liquid or gas, for example: ethylene, butene, isobutene ...
Alkyne with the general formula: C n H 2n-2 (n is an integer, usually from 1 to 20) are linear or branched chain molecules containing two carbon-carbon double bonds, which can be liquid or gas, for example: acetylene, butadienes.

Now that we know the structure of oil, let's see what we can do with it.

How does oil refining work?

The refining process begins with a fractional distillation column.

Typical refinery

The main problem with crude oil is that it contains hundreds of different types hydrocarbons mixed all together. And our job is to separate the different types of hydrocarbons in order to get something useful. Fortunately, there is an easy way to separate these things, and this is what refining does.

Different hydrocarbon chain lengths have progressively higher boiling points so that they can be separated by simple distillation at different temperatures. Simply put, by heating oil to a certain temperature, certain chains of hydrocarbons begin to boil, and, thus, we can separate "grains from chaff". This is what happens in a refinery - in one part of the process, the oil is heated and the various chains are boiled away at their respective boiling points. Each different chain length has its own unique property that makes it useful in its own way.

To understand the diversity found in crude oil, and to understand why refining crude oil is so important to our civilization, take a look at the following list of products that are derived from crude oil:

Petroleum gases- used for heating, cooking, making plastics:

these are small alkanes (from 1 to 4 carbon atoms)
widely known by names such as methane, ethane, propane, butane
boiling range - less than 40 degrees Celsius
gases often liquefied under pressure

Naphtha or naphtha- an intermediate product that will be further processed to subsequently become gasoline:

contains from 5 to 9 carbon atoms of alkanes
boiling range - from 60 to 100 degrees Celsius

Petrol- motor fuel:

always a liquid product
is a mixture of alkanes and cycloalkanes (5 to 12 carbon atoms)
boiling range - from 40 to 205 degrees Celsius

Kerosene- fuel for jet engines and tractors; raw material for the manufacture of other products:

liquid
mixture of alkanes (10 to 18 carbon atoms) and aromatic hydrocarbons
boiling range - from 175 to 325 degrees Celsius

Diesel distillate- used for diesel fuel and fuel oil; raw material for the manufacture of other products:

liquid
alkanes containing 12 or more carbon atoms
boiling range - from 250 to 350 degrees Celsius

Lubricating oils- used for the manufacture of engine oil, fat, other lubricants:

liquid
long chain structures (20 to 50 carbon atoms) alkanes, cycloalkanes, aromatics
boiling range - from 300 to 370 degrees Celsius

Fuel oil- used for industrial fuels; raw material for the manufacture of other products:

liquid
long chain structures (20 to 70 carbon atoms) alkanes, cycloalkanes, aromatics
boiling range - 370 to 600 degrees Celsius

Remains of processed products- coke, asphalt, tar, paraffins; raw material for the manufacture of other products:

solid particles
multiple ring compounds with 70 or more carbon atoms
boiling range of at least 600 degrees Celsius.

You may have noticed that these foods all come in different sizes and boiling ranges. Chemists have taken advantage of these properties for refining. Let's now further learn the details of this fascinating process!

Detailed oil refining process

As mentioned earlier, a barrel of crude oil has a mixture of all kinds of hydrocarbons in it. Oil refining separates useful substances from this whole "racial company". At the same time, the following groups of industrial chemical processes take place, which, in principle, are at every oil refinery:

The oldest and most common way to separate various components (called fractions) from oil is to do so using differences in boiling points. This process is called fractional distillation .
New methods of using chemical treatment in some of the fractions use the conversion method. Chemical treatments, for example, can break long chains into shorter ones. This allows the refinery to convert diesel to gasoline based on demand, for example.
Refineries, in addition, after the fractional distillation process must purify fractions in order to remove impurities from them.
Refineries combine different fractions (processed and unprocessed) in a mixture to make the desired products. For example, different mixtures from different chains can create gasolines with different octane numbers.

Refined petroleum products are sent for short storage in special tanks until they are delivered to various markets: gas stations, airports and chemical plants. In addition to making oil-based products, factories must also take care of the inevitable waste to minimize air and water pollution.

Fractional distillation

The different components of the oil have different sizes, weights and boiling points; so, the first step is to separate these components. Because they have different boiling points, they can be separated easily using a process called fractional distillation.

Fractional distillation steps are as follows:

You heat a mixture of two or more substances (liquids) with different boiling points to a high temperature. Heating is usually done with high pressure steam up to a temperature of about 600 degrees Celsius.
The mixture boils producing steam (gases); most substances pass in the vapor phase.
Steam enters the bottom of a long column, which is filled with trays or trays. The trays have many holes or bubble caps (similar to the perforated lid on plastic bottle) in them to allow steam to pass through them. They increase the contact time between vapor and liquid in the column and aid in the collection of liquids that form at different heights in the column. There is a temperature difference in this column (very hot at the bottom and colder at the top).
Thus, the steam rises in the column.
As the vapor rises through the trays in the column, it cools.
When a vaporous material reaches a height where the column temperature equals the boiling point of that material, it will condense to form a liquid. In this case, substances with the lowest boiling point will condense at the highest point in the column, and substances with higher boiling points will condense lower in the column.
The trays collect various liquid fractions.
The collected liquid fractions can go to condensers, which cool them further, and then go to storage tanks, or they can go to other areas for further chemical processing.

Fractional distillation is useful for separating a mixture of substances with narrow differences in boiling points and is the most important step in the refining process. The refining process begins with a fractional distillation column. Very few of the components will leave the fractionator ready for sale in the petroleum market. Many of them must be chemically treated in order to be converted to other fractions. For example, only 40% of distilled crude oil will become gasoline, however, gasoline is one of the main products produced by oil companies. Instead of constantly distilling in large quantities crude oil, oil companies chemically treating other fractions from the distillation column to obtain the same gasoline; and this treatment increases the yield of gasoline from every barrel of crude oil.

Chemical transformation

You can convert one faction to another using one of three methods:

Break down large hydrocarbons into smaller ones (cracking)
Combine small hydrocarbons to make them larger (unification)
Rearrange or replace different parts of hydrocarbons to obtain the desired hydrocarbons (hydrothermal change)

Cracking

Cracking takes in large hydrocarbons and breaks them down into smaller ones. There are several types of cracking:

Thermal- You heat large hydrocarbons at high temperatures (sometimes also at high pressures) until they decompose.
Steam - heat steam (over 800 degrees Celsius) is used to break down ethane, butane and naphtha into ethylene and benzene, which are used to make chemicals.
Visbreaking- the residues from the distillation column are heated to almost 500 degrees Celsius, cooled and quickly burned in the distillation column. This process reduces the viscosity of substances and the number of heavy oils in them and produces resins.
Coking- the residual substances from the distillation column are heated to a temperature above 450 degrees Celsius, as a result of which heavy almost pure carbon remains (coke); coke is cleaned from coking and sold.
Catalization- a catalyst is used to accelerate the cracking reaction. Catalysts include zeolite, hydrated aluminum silicate, bauxite, and aluminosilicate. Catalytic cracking is when a hot catalyst fluid (538 degrees Celsius) breaks down a heavy substance into diesel oils and gasoline.
Hydrocracking- similar to catalytic cracking, but uses a different catalyst with lower temperatures, high pressure and hydrogen. This allows heavy oil to be broken down into gasoline and kerosene (jet fuel).

Unification

Sometimes you need to combine smaller hydrocarbons to make larger ones - a process called unification. In this case, the main process of unification is catalytic reforming and in this case, a catalyst (a mixture of platinum and platinum-rhenium) is used to combine the low weight of naphtha into aromatics, which are used in the creation of chemicals and in gasoline blending. A significant byproduct of this reaction is hydrogen gas, which is then either used for hydrocracking or simply sold.

Hydrothermal alteration

Sometimes the structures of molecules in one fraction are rearranged to produce another. This is typically done through a process called by alkylation... In alkylation, low molecular weight compounds such as propylene and butylene are mixed in the presence of a catalyst such as hydrofluoric acid or sulfuric acid (a by-product from the removal of impurities from many petroleum products). Alkylation products are high-octane hydrocarbons, which are used in gasoline mixtures to increase the octane number.

Final processing (refining) of petroleum products

Distilled and chemically treated oil fractions are processed again to remove impurities - mainly organic compounds containing sulfur, nitrogen, oxygen, water, dissolved metals and inorganic salts. Finishing is usually done in the following ways:

The sulfuric acid column removes unsaturated hydrocarbons (carbon-carbon-double bonds), nitrogen compounds, oxygen compounds and residual solids (tar, asphalt).
The absorption tower is filled with a desiccant to remove water.
Hydrogen sulfide scrubbers remove sulfur and all sulfur compounds.

After the fractions are processed, they are cooled and then mixed together to make various products such as:

Gasoline of various brands, with or without additives.
Lubricating oils of various brands and types (for example, 10W-40, 5W-30).
Kerosene of various brands.
Jet fuel.
Fuel oil.
Other chemical substances of various brands for the manufacture of plastics and other polymers.

The oil refining process can be divided into 3 main technological processes:

1. Primary processing - Separation of crude oil into fractions of different boiling ranges;

2. Secondary processing - Processing of primary processing fractions by chemical transformation of the hydrocarbons contained in them and the production of commercial oil product components;

3. Commercial production - Mixing of components with the use of various additives, with the receipt of commercial products with specified quality indicators.

The range of products of an oil refinery (refinery) can include up to 40 items, including:

Motor fuel,

Raw materials for petrochemical production,

Lubricating, hydraulic and other oil,

Other n / products.

The nomenclature of n / products obtained at specific refineries depends on the composition and properties of the supplied crude oil and the requirements for n / products.

Faction characteristics:

The gases dissolved in oil in the amount of 1.9% of the mass of oil, and obtained from the primary distillation of oil, consist mainly of propane and butane. These are the feedstock of gas fractionation plants and fuel (household liquefied gas).

Fractions nk -62 and 62-85 o C have a small octane number, therefore they are sent to the isomerization unit to increase the octane number.

Fraction 85-120 о С is a feedstock of catalytic reforming for the production of benzene and toluene, components of high-octane gasoline.

Fractions 85-120 and 120-180 о С - feedstock of catalytic reforming for obtaining components of high-octane gasoline, and a component of jet fuel.

Fraction 180-230 о С - a component of jet and diesel fuel.

Fractions 230-280 о С and 280-350 о С are fractions of summer and winter diesel fuel. The cetane number of the combined fraction is 240 - 350 о С = 55. The pour point is -12 о С. Dewaxing of the fraction 230 - 350 о С allows to obtain winter diesel fuel.

Fraction 350-500 о С - vacuum gas oil - feedstock of catalytic cracking and hydrocracking processes for obtaining high-octane gasoline.

The fraction that boils away at temperatures above 500 ° C - tar - is used as feedstock for thermal cracking, visbreaking, coking, and bitumen production units.

Oil refining is a continuous technological process, the shutdown of which is provided only for scheduled preventive maintenance (PPR), approximately every 3 years.

One of the main tasks of refinery modernization carried out by the companies is to increase the turnaround time, which, for example, for the Moscow Refinery is about 4.5 years.

The main technical unit of the refinery is a technological unit, the complex of equipment of which allows performing all operations of the main technological processes of refining.

Basic operations

1. Delivery and reception of oil.

The main routes for the delivery of raw materials to the refinery:

Trunk oil pipelines (MNP) are the main option for the Russian Federation for the delivery of crude oil,

By rail using tank wagons,

Oil tankers for coastal refineries

Oil enters the plant's oil terminal (Fig. 1) in (usually, Shukhov's type), which is connected by oil pipelines with all the plant's technological units.

The accounting of oil received at the oil terminal is carried out by instruments or by measuring in oil reservoirs.

2. Primary processing

2.1. Oil preparation for refining (electrical desalination).

Desalting serves to reduce corrosion of process equipment from crude oil.

Crude oil coming from oil tanks is mixed with water to dissolve salts and sent to ELOU - an electrical desalination plant.

2.2.3. Stabilization and secondary distillation of gasoline

The gasoline fraction obtained at the AVT unit cannot be used for the following reasons:

Contains gases, mainly propane and butane, in excess of the quality requirements, which does not allow their use as components of motor gasoline or commercial straight-run gasoline,

Refining processes aimed at increasing the octane number of gasoline and the production of aromatic hydrocarbons use narrow gasoline fractions as raw materials.

Therefore, a technical process is used, as a result of which liquefied gases are distilled off from the gasoline fraction, and it is distilled into 2-5 narrow fractions on an appropriate number of columns.

Products of primary oil refining, in fact, like products in other technological processes of refining, are cooled:

In heat exchangers, which saves process fuel,

In water and air refrigerators.

Primary processing unit - usually combined ELOU-AVT-6 with a processing capacity of up to 6 million tons / year of oil, consisting of:

Block ELOU, designed to prepare oil for processing by removing water and salts from it,

Block AT, designed for distillation of light oil products into narrow fractions,

Block VT, designed for distillation of fuel oil (> 350 о С) into fractions,

Stabilization unit designed to remove gaseous components from gasoline, including corrosive hydrogen sulfide and hydrocarbon gases,

A block for the secondary distillation of gasoline fractions, designed to separate gasoline into fractions.

In the standard configuration of the unit, crude oil is mixed with a demulsifier, heated in heat exchangers, desalted in 4 parallel flows in 2 stages of horizontal electric dehydrators, additionally heated in heat exchangers and sent to a topping column.

Heat is supplied to the bottom of this column by a hot jet circulating through the furnace.

Further, partially stripped oil from the column, after heating in the furnace, is sent to the main column, where rectification is carried out to obtain gasoline vapors in the upper part of the column, 3 side distillates from the stripping columns and fuel oil in the lower part of the column.

Heat removal in the column is carried out by the upper evaporative reflux and 2 intermediate circulating refluxes.

The mixture of gasoline fractions from the columns is sent to the column for stabilization, where light head fractions (liquid head) are taken from above, and stable gasoline is taken from the bottom.

Stable gasoline in the columns undergoes secondary distillation to obtain narrow cuts used as feedstock for catalytic reforming.

Heat is supplied to the bottom of the stabilizer and secondary distillation columns by circulating refluxes heated in a furnace.

Photos of primary processing plants of various configurations

3. Secondary oil refining

Primary oil refining products, as a rule, are not marketable n / products.

For example, the octane number of the gasoline fraction is about 65 points, the sulfur content in the diesel fraction can reach 1.0% or more, while the standard is, depending on the brand, 0.005% - 0.2%.

In addition, dark petroleum fractions can be subjected to further qualified processing.

Therefore, petroleum fractions are fed to secondary process units, which improve the quality of oil products and deepen oil refining.

Catalytic cracking () is the most important refining process that significantly affects the efficiency of the refinery as a whole.

The essence of the process is the decomposition of hydrocarbons that make up the feedstock (vacuum gas oil) under the influence of temperature in the presence of a zeolite-containing aluminosilicate catalyst.

The target product of the KK unit is a high-octane component of gasoline with an octane number of 90 p and more, its yield is 50 - 65%, depending on the raw material used, the technology used and the mode.

The high octane number is due to the fact that isomerization also occurs during cat cracking.

During the process, gases containing propylene and butylenes are formed, which are used as feedstock for petrochemicals and the production of high-octane gasoline components, light gas oil - a component of diesel and furnace fuels, and heavy gas oil - a raw material for the production of soot, or a component of fuel oil.

The capacity of modern installations is on average 1.5-2.5 million tons / year, but there are also 4.0 million tons / year.

The key section of the facility is the reactor-regeneration unit.

The unit includes a feed heating furnace, a reactor in which cracking reactions take place, and a catalyst regenerator.

The purpose of the regenerator is to burn off coke formed during cracking and deposited on the catalyst surface. The reactor, regenerator and feedstock input unit are connected by pipelines (pneumatic conveying lines) through which the catalyst circulates.

The catalytic cracking capacity at Russian refineries is currently insufficient, and the introduction of new units is solving the problem with the projected shortage of gasoline.

Raw material with a temperature of 500-520 ° C mixed with a pulverized catalyst moves up the riser reactor for 2-4 seconds and undergoes cracking.

Cracking products enter the separator located at the top of the riser reactor, where chemical reactions are completed and the catalyst is separated, which is removed from the lower part of the separator and flows by gravity into the regenerator, in which coke is burned out at a temperature of 700 ° C.

Thereafter, the recovered catalyst is returned to the feedstock input unit.

The pressure in the reactor-regenerator block is close to atmospheric.

The total height of the reactor-regenerator unit is 30 - 55 m, the diameters of the separator and regenerator are 8 and 11 m, respectively, for a unit with a capacity of 2.0 million tons / year.

Cracking products leave the top of the separator, are cooled and fed to rectification.

Catcracking can be part of combined units, including preliminary hydrotreating or light hydrocracking of feedstock, purification and fractionation of gases.

On the right is the reactor, to the left of it is the regenerator

Hydrocracking is a process aimed at obtaining high-quality kerosene and diesel distillates, as well as vacuum gas oil by cracking hydrocarbons of the feedstock in the presence of hydrogen.

Simultaneously with cracking, products are purified from sulfur, olefins and aromatic compounds are saturated, which leads to high operational and environmental characteristics of the resulting fuels.

The resulting gasoline fraction has a low octane number, its heavy part can serve as a raw material for reforming.

Hydrocracking is also used in oil production to obtain high quality base oils with performance characteristics similar to synthetic ones.

The range of hydrocracking feedstocks is quite wide - straight-run vacuum gas oil, catalytic cracking and coking gas oils, oil block by-products, fuel oil, tar.
Hydrocracking units, as a rule, are built with a large unit processing capacity - 3-4 million tons / year.

Typically, the volume of hydrogen produced in reformers is not enough to support hydrocracking, therefore, separate units for the production of hydrogen by steam reforming of hydrocarbon gases are being built at the refinery.

Technological schemes are fundamentally similar to hydrotreating units - the raw material mixed with hydrogen-containing gas (HSG) is heated in a furnace, enters the reactor with a catalyst bed, the products from the reactor are separated from the gases and fed to rectification.

However, the hydrocracking reactions proceed with the release of heat, therefore, the technological scheme provides for the introduction of cold HSG into the reaction zone, the flow rate of which is controlled by the temperature. Hydrocracking is one of the most dangerous processes in oil refining; when the temperature regime goes out of control, a sharp rise in temperature occurs, leading to an explosion of the reactor block.

The hardware and technological regime of hydrocracking units differ depending on the tasks associated with the technological scheme of a particular refinery and the raw materials used.

For example, to obtain low-sulfur vacuum gas oil and a relatively small amount of light oil (light hydrocracking), the process is carried out at a pressure of up to 80 atm in one reactor at a temperature of about 350 ° C.

For the maximum yield of light (up to 90%, including up to 20% of gasoline fraction for raw materials), the process is carried out in 2 reactors.

In this case, the products after the 1st reactor enter the distillation column, where the light obtained as a result of chemical reactions are distilled off, and the remainder enters the 2nd reactor, where it is re-subjected to hydrocracking.

In this case, in the hydrocracking of vacuum gas oil, the pressure is about 180 atm, and in the hydrocracking of fuel oil and tar - more than 300.

The process temperature, accordingly, varies in the range of 380 - 450 ° C and above.

In Russia, the hydrocracking technology was introduced in the 2000s at refineries in Perm, Yaroslavl and Ufa, at a number of plants, hydrotreating units were reconstructed for the process of light hydrocracking.

The joint construction of hydrocracking and catalytic cracking units within the framework of deep oil refining complexes seems to be the most effective for the production of high-octane gasolines and high-quality middle distillates.

4. Commercial production

In the course of the above technological processes, only components of motor, aviation and boiler fuels with different quality indicators are produced.

For example, the octane number of straight-run gasoline is about 65, reformate - 95-100, coking gasoline - 60.

Other quality indicators (for example, fractional composition, sulfur content) are also different for the components.

To obtain commercial n / products, the resulting components are mixed in the appropriate refinery tanks in ratios that provide standardized quality indicators.

The calculation of the mixing recipe () of the components is carried out using the modules of mathematical models used for planning the production of the refinery as a whole.

The initial data for modeling are the projected balances of raw materials, components and marketable products, the plan for the sale of non-products in the context of the assortment, the planned volume of oil supplies. In this way it is possible to calculate the most effective mixing ratios between the components.

Often, factories use established mixing recipes, which are adjusted when the technological scheme changes.

The components of n / products in a given ratio are pumped into a mixing vessel, where additives can also be supplied.

The received commodity n / products undergo quality control and are pumped into the tanks of the commodity base, from where they are shipped to the consumer.

5. Delivery of petroleum products

Transportation by rail is the main method of delivery of n / products in Russia. Loading racks are used for loading.

On the main oil product pipelines () Transnefteproduct,

River and sea vessels.