family psychology 

Natural sources of aromatic hydrocarbons. Production of aromatic hydrocarbons. natural sources. Composition of minerals

NATURAL SOURCES OF HYDROCARBONS

Hydrocarbons are all so different -
Liquid, solid, and gaseous.
Why are there so many of them in nature?
It's insatiable carbon.

Indeed, this element, like no other, is “insatiable”: it strives to form chains, straight and branched, then rings, then grids from a multitude of its atoms. Hence the many compounds of carbon and hydrogen atoms.

Hydrocarbons are both natural gas - methane, and another household combustible gas, which is filled with cylinders - propane C 3 H 8. Hydrocarbons are oil, gasoline, and kerosene. And also - an organic solvent C 6 H 6, paraffin, from which New Year's candles are made, petroleum jelly from a pharmacy, and even a plastic bag for food packaging ...

The most important natural sources of hydrocarbons are minerals - coal, oil, gas.

COAL

More known around the world 36 thousand coal basins and deposits, which together occupy 15% territories of the globe. Coal fields can stretch for thousands of kilometers. In total, the general geological reserves of coal on the globe are 5 trillion 500 billion tons, including explored deposits - 1 trillion 750 billion tons.

There are three main types of fossil coals. When burning brown coal, anthracite, the flame is invisible, the combustion is smokeless, and coal makes a loud crack when burning.

Anthraciteis the oldest fossil coal. Differs in the big density and gloss. Contains up to 95% carbon.

Coal- contains up to 99% carbon. Of all fossil coals, it is the most widely used.

Brown coal- contains up to 72% carbon. Has a brown color. As the youngest fossil coal, it often retains traces of the structure of the tree from which it was formed. Differs in high hygroscopicity and high ash content ( from 7% to 38%), therefore, it is used only as a local fuel and as a raw material for chemical processing. In particular, valuable types of liquid fuels are obtained by hydrogenation: gasoline and kerosene.

Carbon is the main constituent of coal 99% ), brown coal ( up to 72%). The origin of the name carbon, i.e., “bearing coal”. Similarly, the Latin name "carboneum" at the base contains the root carbo-coal.

Like oil, coal contains a large amount of organic matter. In addition to organic substances, it also includes inorganic substances, such as water, ammonia, hydrogen sulfide and, of course, carbon itself - coal. One of the main ways of coal processing is coking - calcination without air access. As a result of coking, which is carried out at a temperature of 1000 0 C, the following is formed:

coke oven gas- it consists of hydrogen, methane, carbon monoxide and carbon dioxide, impurities of ammonia, nitrogen and other gases.

Coal tar - contains several hundred different organic substances, including benzene and its homologues, phenol and aromatic alcohols, naphthalene and various heterocyclic compounds.

Top-tar or ammonia water - containing, as the name implies, dissolved ammonia, as well as phenol, hydrogen sulfide and other substances.

Coke– solid coking residue, practically pure carbon.

Coke is used in the production of iron and steel, ammonia is used in the production of nitrogen and combined fertilizers, and the importance of organic coking products cannot be overestimated. What is the geography of distribution of this mineral?

The main part of coal resources falls on the northern hemisphere - Asia, North America, Eurasia. What countries stand out in terms of reserves and coal production?

China, USA, India, Australia, Russia.

Countries are the main exporters of coal.

USA, Australia, Russia, South Africa.

main import centers.

Japan, Overseas Europe.

It is a very environmentally dirty fuel. Explosions and fires of methane occur during coal mining, and certain environmental problems arise.

Environmental pollution - this is any undesirable change in the state of this environment as a result of human activities. This also happens in mining. Imagine a situation in a coal mining area. Together with coal, a huge amount of waste rock rises to the surface, which, as unnecessary, is simply sent to dumps. Gradually formed waste heaps- huge, tens of meters high, cone-shaped mountains of waste rock, which distort the appearance of the natural landscape. And will all the coal raised to the surface be necessarily exported to the consumer? Of course not. After all, the process is not hermetic. A huge amount of coal dust settles on the surface of the earth. As a result, the composition of soils and groundwater changes, which will inevitably affect the flora and fauna of the region.

Coal contains radioactive carbon - C, but after the fuel is burned, the hazardous substance, along with smoke, enters the air, water, soil, and is baked into slag or ash, which is used to produce building materials. As a result, in residential buildings, walls and ceilings “glow” and pose a threat to human health.

OIL

Oil has been known to mankind since ancient times. On the banks of the Euphrates, it was mined

6-7 thousand years BC uh . It was used to illuminate dwellings, to prepare mortars, as medicines and ointments, and for embalming. Oil in the ancient world was a formidable weapon: fiery rivers poured on the heads of those who stormed the fortress walls, burning arrows dipped in oil flew to the besieged cities. Oil was an integral part of the incendiary agent that went down in history under the name "Greek fire" In the Middle Ages, it was mainly used for street lighting.

More than 600 oil and gas basins have been explored, 450 are being developed , and the total number of oil fields reaches 50 thousand.

Distinguish between light and heavy oil. Light oil is extracted from the subsoil by pumps or by the fountain method. Mostly gasoline and kerosene are made from such oil. Heavy grades of oil are sometimes extracted even by the mine method (in the Komi Republic), and bitumen, fuel oil, and various oils are prepared from it.

Oil is the most versatile fuel, high-calorie. Its extraction is relatively simple and cheap, because when extracting oil, there is no need to lower people underground. Transporting oil through pipelines is not a big problem. The main disadvantage of this type of fuel is the low availability of resources (about 50 years ) . General geological reserves are equal to 500 billion tons, including explored 140 billion tons .

IN 2007 Russian scientists proved to the world community that the underwater ridges of Lomonosov and Mendeleev, which are located in the Arctic Ocean, are a shelf zone of the mainland, and therefore belong to the Russian Federation. The chemistry teacher will tell about the composition of oil, its properties.

Oil is a "bundle of energy". With only 1 ml of it, you can heat a whole bucket of water by one degree, and in order to boil a bucket samovar, you need less than half a glass of oil. In terms of energy concentration per unit volume, oil ranks first among natural substances. Even radioactive ores cannot compete with it in this regard, since the content of radioactive substances in them is so small that 1mg can be extracted. nuclear fuel must be processed tons of rocks.

Oil is not only the basis of the fuel and energy complex of any state.

Here, the famous words of D. I. Mendeleev are in place “burning oil is the same as heating a furnace banknotes". Each drop of oil contains more than 900 various chemical compounds, more than half of the chemical elements of the Periodic Table. This is truly a miracle of nature, the basis of the petrochemical industry. Approximately 90% of all oil produced is used as fuel. In spite of “ own 10%” , petrochemical synthesis provides many thousands of organic compounds that satisfy the urgent needs of modern society. No wonder people respectfully call oil “black gold”, “the blood of the Earth”.

Oil is an oily dark brown liquid with a reddish or greenish tint, sometimes black, red, blue or light and even transparent with a characteristic pungent odor. Sometimes oil is white or colorless, like water (for example, in the Surukhanskoye field in Azerbaijan, in some fields in Algeria).

The composition of oil is not the same. But all of them usually contain three types of hydrocarbons - alkanes (mainly normal structure), cycloalkanes and aromatic hydrocarbons. The ratio of these hydrocarbons in the oil of different fields is different: for example, Mangyshlak oil is rich in alkanes, and oil in the Baku region is rich in cycloalkanes.

The main oil reserves are in the northern hemisphere. Total 75 countries of the world produce oil, but 90% of its production falls on the share of only 10 countries. About ? world oil reserves are in developing countries. (The teacher calls and shows on the map).

Main producing countries:

Saudi Arabia, USA, Russia, Iran, Mexico.

At the same time more 4/5 oil consumption falls on the share of economically developed countries, which are the main importing countries:

Japan, Overseas Europe, USA.

Oil in its raw form is not used anywhere, but refined products are used.

Oil refining

A modern plant consists of an oil heating furnace and a distillation column where the oil is separated into factions - individual mixtures of hydrocarbons according to their boiling points: gasoline, naphtha, kerosene. The furnace has a long tube coiled into a coil. The furnace is heated by the combustion products of fuel oil or gas. Oil is continuously supplied to the coil: there it is heated to 320 - 350 0 C in the form of a mixture of liquid and vapor and enters the distillation column. The distillation column is a steel cylindrical apparatus with a height of about 40m. It has inside several dozen horizontal partitions with holes - the so-called plates. Oil vapors, entering the column, rise up and pass through the holes in the plates. As they gradually cool as they move upwards, they partially liquefy. Less volatile hydrocarbons are liquefied already on the first plates, forming a gas oil fraction; more volatile hydrocarbons are collected above and form a kerosene fraction; even higher - naphtha fraction. The most volatile hydrocarbons leave the column as vapors and, after condensation, form gasoline. Part of the gasoline is fed back to the column for "irrigation", which contributes to a better mode of operation. (Entry in a notebook). Gasoline - contains hydrocarbons C5 - C11, boiling in the range from 40 0 ​​C to 200 0 C; naphtha - contains hydrocarbons C8 - C14 with a boiling point of 120 0 C to 240 0 C; kerosene - contains hydrocarbons C12 - C18, boiling at a temperature of 180 0 C to 300 0 C; gas oil - contains hydrocarbons C13 - C15, distilled off at a temperature of 230 0 C to 360 0 C; lubricating oils - C16 - C28, boil at a temperature of 350 0 C and above.

After distillation of light products from oil, a viscous black liquid remains - fuel oil. It is a valuable mixture of hydrocarbons. Lubricating oils are obtained from fuel oil by additional distillation. The non-distilling part of fuel oil is called tar, which is used in construction and when paving roads. (Demonstration of a video fragment). The most valuable fraction of direct distillation of oil is gasoline. However, the yield of this fraction does not exceed 17-20% by weight of crude oil. The problem arises: how to meet the ever-increasing needs of society in automotive and aviation fuel? The solution was found at the end of the 19th century by a Russian engineer Vladimir Grigorievich Shukhov. IN 1891 year, he first carried out an industrial cracking kerosene fraction of oil, which made it possible to increase the yield of gasoline to 65-70% (calculated as crude oil). Only for the development of the process of thermal cracking of petroleum products, grateful mankind inscribed the name of this unique person in the history of civilization with golden letters.

The products obtained as a result of oil rectification are subjected to chemical processing, which includes a number of complex processes, one of them is the cracking of petroleum products (from the English "Cracking" - splitting). There are several types of cracking: thermal, catalytic, high pressure cracking, reduction. Thermal cracking consists in the splitting of hydrocarbon molecules with a long chain into shorter ones under the influence of high temperature (470-550 0 C). In the process of this splitting, along with alkanes, alkenes are formed:

Currently, catalytic cracking is the most common. It is carried out at a temperature of 450-500 0 C, but at a higher speed and allows you to get higher quality gasoline. Under the conditions of catalytic cracking, along with cleavage reactions, isomerization reactions take place, that is, the transformation of hydrocarbons of a normal structure into branched hydrocarbons.

Isomerization affects the quality of gasoline, since the presence of branched hydrocarbons greatly increases its octane number. Cracking is referred to the so-called secondary processes of oil refining. A number of other catalytic processes, such as reforming, are also classified as secondary. Reforming- this is the aromatization of gasolines by heating them in the presence of a catalyst, for example, platinum. Under these conditions, alkanes and cycloalkanes are converted into aromatic hydrocarbons, as a result of which the octane number of gasoline also increases significantly.

Ecology and oilfield

For petrochemical production, the problem of the environment is especially relevant. Oil production is associated with energy costs and environmental pollution. A dangerous source of pollution of the oceans is offshore oil production, and the oceans are also polluted during the transportation of oil. Each of us has seen on TV the consequences of oil tanker accidents. Black, oil-covered shores, black surf, choking dolphins, Birds whose wings are covered in viscous oil, people in protective suits collecting oil with shovels and buckets. I would like to cite the data of a serious environmental disaster that occurred in the Kerch Strait in November 2007. 2,000 tons of oil products and about 7,000 tons of sulfur got into the water. The Tuzla Spit, which is located at the junction of the Black and Azov Seas, and the Chushka Spit suffered the most because of the disaster. After the accident, fuel oil settled to the bottom, which killed a small shell-heart-shaped, the main food of the inhabitants of the sea. It will take 10 years to restore the ecosystem. More than 15 thousand birds died. A liter of oil, having fallen into the water, spreads over its surface in spots of 100 sq.m. The oil film, although very thin, forms an insurmountable barrier to the path of oxygen from the atmosphere to the water column. As a result, the oxygen regime and the ocean are disturbed. "suffocate". Plankton, which is the backbone of the ocean food chain, is dying. Currently, about 20% of the area of ​​the World Ocean is covered with oil spills, and the area affected by oil pollution is growing. In addition to the fact that the World Ocean is covered with an oil film, we can also observe it on land. For example, in the oil fields of Western Siberia, more oil is spilled per year than a tanker can hold - up to 20 million tons. About half of this oil ends up on the ground as a result of accidents, the rest is “planned” fountains and leaks during well startups, exploratory drilling, and pipeline repairs. The largest area of ​​oil-contaminated land, according to the Committee for the Environment of the Yamalo-Nenets Autonomous Okrug, falls on the Purovsky District.

NATURAL AND ASSOCIATED PETROLEUM GAS

Natural gas contains hydrocarbons with a low molecular weight, the main components are methane. Its content in the gas of various fields ranges from 80% to 97%. In addition to methane - ethane, propane, butane. Inorganic: nitrogen - 2%; CO2; H2O; H2S, noble gases. When natural gas is burned, a lot of heat is released.

In terms of its properties, natural gas as a fuel surpasses even oil, it is more caloric. This is the youngest branch of the fuel industry. Gas is even easier to extract and transport. It is the most economical of all fuels. True, there are also disadvantages: the complex intercontinental transportation of gas. Tankers - methane manure, transporting gas in a liquefied state, are extremely complex and expensive structures.

It is used as: effective fuel, raw material in the chemical industry, in the production of acetylene, ethylene, hydrogen, soot, plastics, acetic acid, dyes, medicines, etc. production. Petroleum gas contains less methane, but more propane, butane and other higher hydrocarbons. Where is the gas produced?

More than 70 countries of the world have commercial gas reserves. Moreover, as in the case of oil, developing countries have very large reserves. But gas production is carried out mainly by developed countries. They have opportunities to use it or a way to sell gas to other countries that are on the same continent with them. International gas trade is less active than oil trade. About 15% of the world's produced gas enters the international market. Almost 2/3 of world gas production is provided by Russia and the USA. Undoubtedly, the leading gas production region not only in our country, but also in the world is the Yamalo-Nenets Autonomous Okrug, where this industry has been developing for 30 years. Our city Novy Urengoy is rightfully recognized as the gas capital. The largest deposits include Urengoyskoye, Yamburgskoye, Medvezhye, Zapolyarnoye. The Urengoy field is included in the Guinness Book of Records. The reserves and production of the deposit are unique. Explored reserves exceed 10 trillion. m 3 , 6 trln. m 3. In 2008 JSC "Gazprom" plans to produce 598 billion m 3 of "blue gold" at the Urengoy field.

Gas and ecology

The imperfection of the technology of oil and gas production, their transportation causes the constant burning of the volume of gas in the heat units of compressor stations and in flares. Compressor stations account for about 30% of these emissions. About 450,000 tons of natural and associated gas are burned annually at flare installations, while more than 60,000 tons of pollutants enter the atmosphere.

Oil, gas, coal are valuable raw materials for the chemical industry. In the near future, they will find a replacement in the fuel and energy complex of our country. Currently, scientists are looking for ways to use solar and wind energy, nuclear fuel in order to completely replace oil. Hydrogen is the most promising fuel of the future. Reducing the use of oil in thermal power engineering is the way not only to its more rational use, but also to the preservation of this raw material for future generations. Hydrocarbon raw materials should be used only in the processing industry to obtain a variety of products. Unfortunately, the situation is not changing yet, and up to 94% of the produced oil is used as fuel. D. I. Mendeleev wisely said: “Burning oil is the same as heating the furnace with banknotes.”

Compounds containing only carbon and hydrogen atoms.

Hydrocarbons are divided into cyclic (carbocyclic compounds) and acyclic.

Cyclic (carbocyclic) compounds are called compounds that include one or more cycles consisting only of carbon atoms (as opposed to heterocyclic compounds containing heteroatoms - nitrogen, sulfur, oxygen, etc.). Carbocyclic compounds, in turn, are divided into aromatic and non-aromatic (alicyclic) compounds.

Acyclic hydrocarbons include organic compounds whose carbon skeleton of molecules is open chains.

These chains can be formed by single bonds (al-kanes), contain one double bond (alkenes), two or more double bonds (dienes or polyenes), one triple bond (alkynes).

As you know, carbon chains are part of most organic substances. Thus, the study of hydrocarbons is of particular importance, since these compounds are the structural basis of other classes of organic compounds.

In addition, hydrocarbons, especially alkanes, are the main natural sources of organic compounds and the basis of the most important industrial and laboratory syntheses (Scheme 1).

You already know that hydrocarbons are the most important feedstock for the chemical industry. In turn, hydrocarbons are quite widespread in nature and can be isolated from various natural sources: oil, associated petroleum and natural gas, coal. Let's consider them in more detail.

Oil- a natural complex mixture of hydrocarbons, mainly linear and branched alkanes, containing from 5 to 50 carbon atoms in molecules, with other organic substances. Its composition significantly depends on the place of its extraction (deposit), it can, in addition to alkanes, contain cycloalkanes and aromatic hydrocarbons.

Gaseous and solid components of oil are dissolved in its liquid components, which determines its state of aggregation. Oil is an oily liquid of dark (from brown to black) color with a characteristic odor, insoluble in water. Its density is less than that of water, therefore, getting into it, oil spreads over the surface, preventing the dissolution of oxygen and other air gases in water. Obviously, getting into natural water bodies, oil causes the death of microorganisms and animals, leading to environmental disasters and even catastrophes. There are bacteria that can use the components of oil as food, converting it into harmless products of their vital activity. It is clear that the use of cultures of these bacteria is the most environmentally safe and promising way to combat oil pollution in the process of its production, transportation and processing.

In nature, oil and associated petroleum gas, which will be discussed below, fill the cavities of the earth's interior. Being a mixture of various substances, oil does not have a constant boiling point. It is clear that each of its components retains its individual physical properties in the mixture, which makes it possible to separate the oil into its components. To do this, it is purified from mechanical impurities, sulfur-containing compounds and subjected to the so-called fractional distillation, or rectification.

Fractional distillation is a physical method for separating a mixture of components with different boiling points.

Distillation is carried out in special installations - distillation columns, in which the cycles of condensation and evaporation of liquid substances contained in oil are repeated (Fig. 9).

Vapors formed during the boiling of a mixture of substances are enriched with a lighter-boiling (i.e., having a lower temperature) component. These vapors are collected, condensed (cooled to below boiling point) and brought back to a boil. In this case, vapors are formed that are even more enriched with a low-boiling substance. By repeated repetition of these cycles, it is possible to achieve almost complete separation of the substances contained in the mixture.

The distillation column receives oil heated in a tubular furnace to a temperature of 320-350 °C. The distillation column has horizontal partitions with holes - the so-called plates, on which the oil fractions condense. Light-boiling fractions accumulate on the higher ones, high-boiling fractions on the lower ones.

In the process of rectification, oil is divided into the following fractions:

Rectification gases - a mixture of low molecular weight hydrocarbons, mainly propane and butane, with a boiling point of up to 40 ° C;

Gasoline fraction (gasoline) - hydrocarbons of composition from C 5 H 12 to C 11 H 24 (boiling point 40-200 ° C); with a finer separation of this fraction, gasoline (petroleum ether, 40-70 ° C) and gasoline (70-120 ° C) are obtained;

Naphtha fraction - hydrocarbons of composition from C8H18 to C14H30 (boiling point 150-250 ° C);

Kerosene fraction - hydrocarbons of composition from C12H26 to C18H38 (boiling point 180-300 ° C);

Diesel fuel - hydrocarbons of composition from C13H28 to C19H36 (boiling point 200-350 ° C).

Residue of oil distillation - fuel oil- contains hydrocarbons with the number of carbon atoms from 18 to 50. Distillation under reduced pressure from fuel oil produces solar oil (C18H28-C25H52), lubricating oils (C28H58-C38H78), vaseline and paraffin - fusible mixtures of solid hydrocarbons. The solid residue of fuel oil distillation - tar and its processing products - bitumen and asphalt are used for the manufacture of road surfaces.

The products obtained as a result of oil rectification are subjected to chemical processing, which includes a number of complex processes. One of them is the cracking of petroleum products. You already know that fuel oil is separated into components under reduced pressure. This is due to the fact that at atmospheric pressure, its components begin to decompose before reaching the boiling point. This is what underlies cracking.

Cracking - thermal decomposition of petroleum products, leading to the formation of hydrocarbons with a smaller number of carbon atoms in the molecule.

There are several types of cracking: thermal cracking, catalytic cracking, high pressure cracking, reduction cracking.

Thermal cracking consists in the splitting of hydrocarbon molecules with a long carbon chain into shorter ones under the influence of high temperature (470-550 ° C). In the process of this splitting, along with alkanes, alkenes are formed.

In general, this reaction can be written as follows:

C n H 2n+2 -> C n-k H 2(n-k)+2 + C k H 2k
alkane alkane alkene
long chain

The resulting hydrocarbons can be cracked again to form alkanes and alkenes with an even shorter chain of carbon atoms in the molecule:

During conventional thermal cracking, many low molecular weight gaseous hydrocarbons are formed, which can be used as raw materials for the production of alcohols, carboxylic acids, and high molecular weight compounds (for example, polyethylene).

catalytic cracking occurs in the presence of catalysts, which are used as natural aluminosilicates of the composition

The implementation of cracking using catalysts leads to the formation of hydrocarbons having a branched or closed chain of carbon atoms in the molecule. The content of hydrocarbons of such a structure in motor fuel significantly improves its quality, primarily knock resistance - the octane number of gasoline.

Cracking of petroleum products proceeds at high temperatures, so carbon deposits (soot) are often formed, contaminating the surface of the catalyst, which sharply reduces its activity.

Cleaning the catalyst surface from carbon deposits - its regeneration - is the main condition for the practical implementation of catalytic cracking. The simplest and cheapest way to regenerate a catalyst is its roasting, during which carbon deposits are oxidized by atmospheric oxygen. Gaseous oxidation products (mainly carbon dioxide and sulfur dioxide) are removed from the catalyst surface.

Catalytic cracking is a heterogeneous process involving solid (catalyst) and gaseous (hydrocarbon vapor) substances. It is obvious that the regeneration of the catalyst - the interaction of solid deposits with atmospheric oxygen - is also a heterogeneous process.

heterogeneous reactions(gas - solid) flow faster as the surface area of ​​the solid increases. Therefore, the catalyst is crushed, and its regeneration and cracking of hydrocarbons are carried out in a "fluidized bed", familiar to you from the production of sulfuric acid.

The cracking feedstock, such as gas oil, enters the conical reactor. The lower part of the reactor has a smaller diameter, so the feed vapor flow rate is very high. The gas moving at high speed captures the catalyst particles and carries them to the upper part of the reactor, where, due to the increase in its diameter, the flow rate decreases. Under the action of gravity, the catalyst particles fall into the lower, narrower part of the reactor, from where they are again carried upwards. Thus, each grain of the catalyst is in constant motion and is washed from all sides by a gaseous reagent.

Some catalyst grains enter the outer, wider part of the reactor and, without encountering gas flow resistance, sink to the lower part, where they are picked up by the gas flow and carried away to the regenerator. There, too, in the "fluidized bed" mode, the catalyst is burned and returned to the reactor.

Thus, the catalyst circulates between the reactor and the regenerator, and the gaseous products of cracking and roasting are removed from them.

The use of cracking catalysts makes it possible to slightly increase the reaction rate, reduce its temperature, and improve the quality of cracked products.

The obtained hydrocarbons of the gasoline fraction mainly have a linear structure, which leads to a low knock resistance of the obtained gasoline.

We will consider the concept of “knock resistance” later, for now we only note that hydrocarbons with branched molecules have a much greater detonation resistance. It is possible to increase the proportion of isomeric branched hydrocarbons in the mixture formed during cracking by adding isomerization catalysts to the system.

Oil fields contain, as a rule, large accumulations of the so-called associated petroleum gas, which collects above the oil in the earth's crust and partially dissolves in it under the pressure of the overlying rocks. Like oil, associated petroleum gas is a valuable natural source of hydrocarbons. It contains mainly alkanes, which have from 1 to 6 carbon atoms in their molecules. Obviously, the composition of associated petroleum gas is much poorer than oil. However, despite this, it is also widely used both as a fuel and as a raw material for the chemical industry. Until a few decades ago, in most oil fields, associated petroleum gas was burned as a useless addition to oil. At present, for example, in Surgut, Russia's richest oil pantry, the world's cheapest electricity is generated using associated petroleum gas as fuel.

As already noted, associated petroleum gas is richer in composition in various hydrocarbons than natural gas. Dividing them into fractions, they get:

Natural gasoline - a highly volatile mixture consisting mainly of lentane and hexane;

Propane-butane mixture, consisting, as the name implies, of propane and butane and easily turns into a liquid state when pressure increases;

Dry gas - a mixture containing mainly methane and ethane.

Natural gasoline, being a mixture of volatile components with a small molecular weight, evaporates well even at low temperatures. This makes it possible to use gas gasoline as a fuel for internal combustion engines in the Far North and as an additive to motor fuel, which makes it easier to start engines in winter conditions.

A propane-butane mixture in the form of liquefied gas is used as household fuel (gas cylinders familiar to you in the country) and for filling lighters. The gradual transition of road transport to liquefied gas is one of the main ways to overcome the global fuel crisis and solve environmental problems.

Dry gas, close in composition to natural gas, is also widely used as a fuel.

However, the use of associated petroleum gas and its components as a fuel is far from the most promising way to use it.

It is much more efficient to use associated petroleum gas components as feedstock for chemical production. Hydrogen, acetylene, unsaturated and aromatic hydrocarbons and their derivatives are obtained from alkanes, which are part of associated petroleum gas.

Gaseous hydrocarbons can not only accompany oil in the earth's crust, but also form independent accumulations - natural gas deposits.

Natural gas - a mixture of gaseous saturated hydrocarbons with a small molecular weight. The main component of natural gas is methane, the share of which, depending on the field, ranges from 75 to 99% by volume. In addition to methane, natural gas contains ethane, propane, butane and isobutane, as well as nitrogen and carbon dioxide.

Like associated petroleum gas, natural gas is used both as a fuel and as a raw material for the production of various organic and inorganic substances. You already know that hydrogen, acetylene and methyl alcohol, formaldehyde and formic acid, and many other organic substances are obtained from methane, the main component of natural gas. As a fuel, natural gas is used in power plants, in boiler systems for water heating of residential buildings and industrial buildings, in blast furnace and open-hearth production. Striking a match and lighting gas in the kitchen gas stove of a city house, you "start" a chain reaction of oxidation of alkanes, which are part of natural gas. , In addition to oil, natural and associated petroleum gases, coal is a natural source of hydrocarbons. 0n forms powerful layers in the bowels of the earth, its explored reserves significantly exceed those of oil. Like oil, coal contains a large amount of various organic substances. In addition to organic, it also includes inorganic substances, such as water, ammonia, hydrogen sulfide and, of course, carbon itself - coal. One of the main ways of coal processing is coking - calcination without air access. As a result of coking, which is carried out at a temperature of about 1000 ° C, the following are formed:

Coke oven gas, which includes hydrogen, methane, carbon monoxide and carbon dioxide, impurities of ammonia, nitrogen and other gases;
coal tar containing several hundred different organic substances, including benzene and its homologues, phenol and aromatic alcohols, naphthalene and various heterocyclic compounds;
over-tar, or ammonia water, containing, as the name implies, dissolved ammonia, as well as phenol, hydrogen sulfide and other substances;
coke - solid residue of coking, almost pure carbon.

coke used in the production of iron and steel, ammonia - in the production of nitrogen and combined fertilizers, and the importance of organic coking products can hardly be overestimated.

Thus, associated petroleum and natural gases, coal are not only the most valuable sources of hydrocarbons, but also part of the unique pantry of irreplaceable natural resources, the careful and reasonable use of which is a necessary condition for the progressive development of human society.

1. List the main natural sources of hydrocarbons. What organic substances are included in each of them? What do they have in common?

2. Describe the physical properties of oil. Why doesn't it have a constant boiling point?

3. After summarizing the media reports, describe the environmental disasters caused by the oil spill and how to overcome their consequences.

4. What is rectification? What is this process based on? Name the fractions obtained as a result of oil rectification. How do they differ from each other?

5. What is cracking? Give the equations of three reactions corresponding to the cracking of petroleum products.

6. What types of cracking do you know? What do these processes have in common? How do they differ from each other? What is the fundamental difference between different types of cracked products?

7. Why is associated petroleum gas so named? What are its main components and their uses?

8. How does natural gas differ from associated petroleum gas? What do they have in common? Give the equations of combustion reactions of all components of associated petroleum gas known to you.

9. Give the reaction equations that can be used to obtain benzene from natural gas. Specify the conditions for these reactions.

10. What is coking? What are its products and their composition? Give the equations of reactions typical for the products of coal coking known to you.

11. Explain why burning oil, coal and associated petroleum gas is far from being the most rational way to use them.

Target. Generalize knowledge about natural sources of organic compounds and their processing; show the successes and prospects for the development of petrochemistry and coke chemistry, their role in the technical progress of the country; deepen knowledge from the course of economic geography about the gas industry, modern directions of gas processing, raw materials and energy problems; develop independence in working with a textbook, reference and popular science literature.

PLAN

Natural sources of hydrocarbons. Natural gas. Associated petroleum gases.
Oil and oil products, their application.
Thermal and catalytic cracking.
Coke production and the problem of obtaining liquid fuel.
From the history of the development of OJSC Rosneft-KNOS.
The production capacity of the plant. Manufactured products.
Communication with the chemical laboratory.
Environmental protection in the factory.
Plant plans for the future.

Natural sources of hydrocarbons.
Natural gas. Associated petroleum gases

Before the Great Patriotic War, industrial stocks natural gas were known in the Carpathian region, in the Caucasus, in the Volga region and in the North (Komi ASSR). The study of natural gas reserves was associated only with oil exploration. Industrial reserves of natural gas in 1940 amounted to 15 billion m 3 . Then gas fields were discovered in the North Caucasus, Transcaucasia, Ukraine, the Volga region, Central Asia, Western Siberia and the Far East. On the
On January 1, 1976, explored reserves of natural gas amounted to 25.8 trillion m 3, of which 4.2 trillion m 3 (16.3%) in the European part of the USSR, 21.6 trillion m 3 (83.7 %), including
18.2 trillion m 3 (70.5%) - in Siberia and the Far East, 3.4 trillion m 3 (13.2%) - in Central Asia and Kazakhstan. As of January 1, 1980, potential reserves of natural gas amounted to 80–85 trillion m 3 , explored - 34.3 trillion m 3 . Moreover, the reserves increased mainly due to the discovery of deposits in the eastern part of the country - explored reserves there were at a level of about
30.1 trillion m 3, which was 87.8% of the all-Union.
Today, Russia has 35% of the world's natural gas reserves, which is more than 48 trillion m 3 . The main areas of occurrence of natural gas in Russia and the CIS countries (fields):

West Siberian oil and gas province:
Urengoyskoye, Yamburgskoye, Zapolyarnoye, Medvezhye, Nadymskoye, Tazovskoye – Yamalo-Nenets Autonomous Okrug;
Pokhromskoye, Igrimskoye - Berezovskaya gas-bearing region;
Meldzhinskoye, Luginetskoye, Ust-Silginskoye - Vasyugan gas-bearing region.
Volga-Ural oil and gas province:
the most significant is Vuktylskoye, in the Timan-Pechora oil and gas region.
Central Asia and Kazakhstan:
the most significant in Central Asia is Gazli, in the Ferghana Valley;
Kyzylkum, Bairam-Ali, Darvaza, Achak, Shatlyk.
North Caucasus and Transcaucasia:
Karadag, Duvanny - Azerbaijan;
Dagestan Lights - Dagestan;
Severo-Stavropolskoye, Pelagiadinskoye - Stavropol Territory;
Leningradskoye, Maykopskoye, Staro-Minskoye, Berezanskoye - Krasnodar Territory.

Also, natural gas deposits are known in Ukraine, Sakhalin and the Far East.
In terms of natural gas reserves, Western Siberia stands out (Urengoyskoye, Yamburgskoye, Zapolyarnoye, Medvezhye). Industrial reserves here reach 14 trillion m 3 . The Yamal gas condensate fields (Bovanenkovskoye, Kruzenshternskoye, Kharasaveyskoye, etc.) are now acquiring particular importance. On their basis, the Yamal-Europe project is being implemented.
Natural gas production is highly concentrated and focused on areas with the largest and most profitable deposits. Only five deposits - Urengoyskoye, Yamburgskoye, Zapolyarnoye, Medvezhye and Orenburgskoye - contain 1/2 of all industrial reserves of Russia. The reserves of Medvezhye are estimated at 1.5 trillion m 3 , and those of Urengoy – at 5 trillion m 3 .
The next feature is the dynamic location of natural gas production sites, which is explained by the rapid expansion of the boundaries of the identified resources, as well as the relative ease and cheapness of their involvement in development. In a short time, the main centers for the extraction of natural gas moved from the Volga region to Ukraine, the North Caucasus. Further territorial shifts were caused by the development of deposits in Western Siberia, Central Asia, the Urals and the North.

After the collapse of the USSR in Russia, there was a drop in the volume of natural gas production. The decline was observed mainly in the Northern economic region (8 billion m 3 in 1990 and 4 billion m 3 in 1994), in the Urals (43 billion m 3 and 35 billion m And
555 billion m 3) and in the North Caucasus (6 and 4 billion m 3). Natural gas production remained at the same level in the Volga region (6 bcm) and in the Far East economic regions.
At the end of 1994, there was an upward trend in production levels.
Of the republics of the former USSR, the Russian Federation provides the most gas, in second place is Turkmenistan (more than 1/10), followed by Uzbekistan and Ukraine.
Of particular importance is the extraction of natural gas on the shelf of the World Ocean. In 1987, offshore fields produced 12.2 billion m 3 , or about 2% of the gas produced in the country. Associated gas production in the same year amounted to 41.9 bcm. For many areas, one of the reserves of gaseous fuel is the gasification of coal and shale. Underground gasification of coal is carried out in the Donbass (Lysichansk), Kuzbass (Kiselevsk) and the Moscow Basin (Tula).
Natural gas has been and remains an important export product in Russian foreign trade.
The main natural gas processing centers are located in the Urals (Orenburg, Shkapovo, Almetyevsk), in Western Siberia (Nizhnevartovsk, Surgut), in the Volga region (Saratov), ​​in the North Caucasus (Grozny) and in other gas-bearing provinces. It can be noted that gas processing plants tend to sources of raw materials - deposits and large gas pipelines.
The most important use of natural gas is as a fuel. Recently, there has been a trend towards an increase in the share of natural gas in the country's fuel balance.

The most valued natural gas with a high content of methane is Stavropol (97.8% CH 4), Saratov (93.4%), Urengoy (95.16%).
Natural gas reserves on our planet are very large (approximately 1015 m 3). More than 200 deposits are known in Russia, they are located in Western Siberia, in the Volga-Ural basin, in the North Caucasus. Russia holds the first place in the world in terms of natural gas reserves.
Natural gas is the most valuable type of fuel. When gas is burned, a lot of heat is released, so it serves as an energy-efficient and cheap fuel in boiler plants, blast furnaces, open-hearth furnaces and glass melting furnaces. The use of natural gas in production makes it possible to significantly increase labor productivity.
Natural gas is a source of raw materials for the chemical industry: the production of acetylene, ethylene, hydrogen, soot, various plastics, acetic acid, dyes, medicines and other products.

Associated petroleum gas- this is a gas that exists together with oil, it is dissolved in oil and is located above it, forming a "gas cap", under pressure. At the exit from the well, the pressure drops, and the associated gas is separated from the oil. This gas was not used in the past, but was simply burned. It is currently being captured and used as a fuel and valuable chemical feedstock. The possibilities of using associated gases are even wider than those of natural gas. their composition is richer. Associated gases contain less methane than natural gas, but they contain significantly more methane homologues. In order to use associated gas more rationally, it is divided into mixtures of a narrower composition. After separation, gas gasoline, propane and butane, dry gas are obtained. Individual hydrocarbons are also extracted - ethane, propane, butane and others. By dehydrogenating them, unsaturated hydrocarbons are obtained - ethylene, propylene, butylene, etc.

Oil and oil products, their application

Oil is an oily liquid with a pungent odor. It is found in many places on the globe, impregnating porous rocks at various depths.
According to most scientists, oil is the geochemically altered remains of plants and animals that once inhabited the globe. This theory of the organic origin of oil is supported by the fact that oil contains some nitrogenous substances - the decomposition products of substances present in plant tissues. There are also theories about the inorganic origin of oil: its formation as a result of the action of water in the strata of the globe on hot metal carbides (compounds of metals with carbon), followed by a change in the resulting hydrocarbons under the influence of high temperature, high pressure, exposure to metals, air, hydrogen, etc.
When oil is extracted from oil-bearing strata, which sometimes lie in the earth's crust at a depth of several kilometers, oil either comes to the surface under the pressure of gases located on it, or is pumped out by pumps.

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? Oil is a raw material for petrochemistry 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 material for obtaining a number of protein preparations used as additives in livestock feed to stimulate its growth.
Oil is our national wealth, the source of the country's power, the foundation of its economy. The oil complex of Russia includes 148 thousand oil wells, 48.3 thousand km of main oil pipelines, 28 oil refineries with a total capacity of more than 300 million tons of oil per year, as well as a large number of other production facilities.
About 900 thousand people are employed at the enterprises of the oil industry and its service industries, including about 20 thousand people in the field of science and scientific services.
Over the past decades, fundamental changes have taken place in the structure of the fuel industry associated with a decrease in the share of the coal industry and the growth of oil and gas extraction and processing industries. If in 1940 they amounted to 20.5%, then in 1984 - 75.3% of the total production of mineral fuel. Now natural gas and open pit coal are coming to the fore. The consumption of oil for energy purposes will be reduced, on the contrary, its use as a chemical raw material will expand. Currently, in the structure of the fuel and energy balance, oil and gas account for 74%, while the share of oil is declining, while the share of gas is growing and is approximately 41%. The share of coal is 20%, the remaining 6% is electricity.
Oil refining was first started by the Dubinin brothers in the Caucasus. Primary oil refining consists in its distillation. Distillation is carried out at refineries after the separation of petroleum gases.

A variety of products of great practical importance are isolated from oil. First, dissolved gaseous hydrocarbons (mainly methane) are removed from it. After distillation of volatile hydrocarbons, the oil is heated. Hydrocarbons with a small number of carbon atoms in the molecule, which have a relatively low boiling point, are the first to go into a vapor state and are distilled off. As the temperature of the mixture rises, hydrocarbons with a higher boiling point are distilled. In this way, individual mixtures (fractions) of oil can be collected. Most often, with this distillation, four volatile fractions are obtained, which are then subjected to further separation.
The main oil fractions are as follows.
Gasoline fraction, collected from 40 to 200 ° C, contains hydrocarbons from C 5 H 12 to C 11 H 24. Upon further distillation of the isolated fraction, gasoline (t kip = 40–70 °C), petrol
(t kip \u003d 70–120 ° С) - aviation, automobile, etc.
Naphtha fraction, collected in the range from 150 to 250 ° C, contains hydrocarbons from C 8 H 18 to C 14 H 30. Naphtha is used as fuel for tractors. Large quantities of naphtha are processed into gasoline.
Kerosene fraction includes hydrocarbons from C 12 H 26 to C 18 H 38 with a boiling point of 180 to 300 °C. Kerosene, after being refined, is used as a fuel for tractors, jet planes and rockets.
Gas oil fraction (t bale > 275 °C), otherwise called diesel fuel.
Residue after distillation of oil - fuel oil- contains hydrocarbons with a large number of carbon atoms (up to many tens) in the molecule. The fuel oil is also fractionated by reduced pressure distillation to avoid decomposition. As a result, get solar oils(diesel fuel), lubricating oils(autotractor, aviation, industrial, etc.), petrolatum(technical petroleum jelly is used to lubricate metal products in order to protect them from corrosion, purified petroleum jelly is used as a basis for cosmetics and in medicine). From some types of oil paraffin(for the production of matches, candles, etc.). After distillation of volatile components from fuel oil remains tar. It is widely used in road construction. In addition to processing into lubricating oils, fuel oil is also used as liquid fuel in boiler plants. Gasoline obtained during the distillation of oil is not enough to cover all needs. In the best case, up to 20% of gasoline can be obtained from oil, the rest is high-boiling products. In this regard, chemistry faced the task of finding ways to obtain gasoline in large quantities. A convenient way was found with the help of the theory of the structure of organic compounds created by A.M. Butlerov. High-boiling oil distillation products are unsuitable for use as a motor fuel. Their high boiling point is due to the fact that the molecules of such hydrocarbons are too long chains. If large molecules containing up to 18 carbon atoms are broken down, low-boiling products such as gasoline are obtained. This way was followed by the Russian engineer V.G. Shukhov, who in 1891 developed a method for the splitting of complex hydrocarbons, later called cracking (which means splitting).

The fundamental improvement of cracking was the introduction of the catalytic cracking process into practice. This process was first carried out in 1918 by N.D. Zelinsky. Catalytic cracking made it possible to obtain aviation gasoline on a large scale. In catalytic cracking units at a temperature of 450 °C, under the action of catalysts, long carbon chains are split.

Thermal and catalytic cracking

The main way of processing oil fractions are various types of cracking. For the first time (1871–1878), oil cracking was carried out on a laboratory and semi-industrial scale by A.A. Letniy, an employee of the St. Petersburg Technological Institute. The first patent for a cracking plant was filed by Shukhov in 1891. Cracking has become widespread in industry since the 1920s.
Cracking is the thermal decomposition of hydrocarbons and other constituents of oil. The higher the temperature, the greater the cracking rate and the greater the yield of gases and aromatics.
Cracking of oil fractions, in addition to liquid products, produces a raw material of paramount importance - gases containing unsaturated hydrocarbons (olefins).
There are the following main types of cracking:
liquid phase (20–60 atm, 430–550 °C), gives unsaturated and saturated gasoline, gasoline yield is about 50%, gases 10%;
headspace(normal or reduced pressure, 600 °C), gives unsaturated aromatic gasoline, the yield is less than with liquid-phase cracking, a large amount of gases is formed;
pyrolysis oil (normal or reduced pressure, 650–700 °C), gives a mixture of aromatic hydrocarbons (pyrobenzene), a yield of about 15%, more than half of the raw material is converted into gases;
destructive hydrogenation (hydrogen pressure 200–250 atm, 300–400 °C in the presence of catalysts - iron, nickel, tungsten, etc.), gives marginal gasoline with a yield of up to 90%;
catalytic cracking (300–500 °С in the presence of catalysts - AlCl 3 , aluminosilicates, MoS 3 , Cr 2 O 3 , etc.), gives gaseous products and high-grade gasoline with a predominance of aromatic and saturated hydrocarbons of isostructure.
In technology, the so-called catalytic reforming– conversion of low-grade gasolines into high-grade high-octane gasolines or aromatic hydrocarbons.
The main reactions during cracking are the reactions of splitting hydrocarbon chains, isomerization and cyclization. Free hydrocarbon radicals play a huge role in these processes.

Coke production
and the problem of obtaining liquid fuel

Stocks hard coal in nature far exceed oil reserves. Therefore, coal is the most important type of raw material for the chemical industry.
Currently, industry uses several ways of coal processing: dry distillation (coking, semi-coking), hydrogenation, incomplete combustion, and calcium carbide production.

Dry distillation of coal is used to obtain coke in metallurgy or domestic gas. When coking coal, coke, coal tar, tar water and coking gases are obtained.
Coal tar contains a wide variety of aromatic and other organic compounds. It is separated into several fractions by distillation at normal pressure. Aromatic hydrocarbons, phenols, etc. are obtained from coal tar.
coking gases contain mainly methane, ethylene, hydrogen and carbon monoxide (II). Some are burned, some are recycled.
Hydrogenation of coal is carried out at 400–600 °C under a hydrogen pressure of up to 250 atm in the presence of a catalyst, iron oxides. This produces a liquid mixture of hydrocarbons, which are usually subjected to hydrogenation on Nickel or other catalysts. Low-grade brown coals can be hydrogenated.

Calcium carbide CaC 2 is obtained from coal (coke, anthracite) and lime. Later it is converted into acetylene, which is used in the chemical industry of all countries on an ever-increasing scale.

From the history of the development of OJSC Rosneft-KNOS

The history of the development of the plant is closely connected with the oil and gas industry of the Kuban.
The beginning of oil production in our country is a distant past. Back in the X century. Azerbaijan traded oil with various countries. In the Kuban, industrial oil development began in 1864 in the Maykop region. At the request of the head of the Kuban region, General Karmalin, D.I. Mendeleev in 1880 gave an opinion on the oil content of the Kuban: Ilskaya".
During the years of the first five-year plans, large-scale prospecting work was carried out and commercial oil production began. Associated petroleum gas was partially used as household fuel in workers' settlements, and most of this valuable product was flared. In order to put an end to the wastefulness of natural resources, the USSR Ministry of the Oil Industry in 1952 decided to build a gas and gasoline plant in the village of Afipsky.
During 1963, an act was signed for the commissioning of the first stage of the Afipsky gas and gasoline plant.
At the beginning of 1964, the processing of gas condensates from the Krasnodar Territory began with the production of A-66 gasoline and diesel fuel. The raw material was gas from Kanevsky, Berezansky, Leningradsky, Maikopsky and other large fields. Improving production, the staff of the plant mastered the production of B-70 aviation gasoline and A-72 gasoline.
In August 1970, two new technological units for the processing of gas condensate with the production of aromatics (benzene, toluene, xylene) were put into operation: a secondary distillation unit and a catalytic reforming unit. At the same time, treatment facilities with biological wastewater treatment and the commodity and raw material base of the plant were built.
In 1975, a plant for the production of xylenes was put into operation, and in 1978, an import-made toluene demethylation plant was put into operation. The plant has become one of the leaders in the Minnefteprom for the production of aromatic hydrocarbons for the chemical industry.
In order to improve the management structure of the enterprise and the organization of production units in January 1980, the production association Krasnodarnefteorgsintez was established. The association included three plants: the Krasnodar site (in operation since August 1922), the Tuapse oil refinery (in operation since 1929) and the Afipsky oil refinery (in operation since December 1963).
In December 1993, the enterprise was reorganized, and in May 1994 Krasnodarnefteorgsintez OJSC was renamed into Rosneft-Krasnodarnefteorgsintez OJSC.

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Ending to be

Lesson Objectives:

Training:

  • To develop the cognitive activity of students.
  • To acquaint students with natural sources of hydrocarbons: oil, natural gas, coal, their composition and processing methods.
  • To study the main deposits of these resources on a global scale and in Russia.
  • Show their importance in the national economy.
  • Consider environmental protection issues.

Educational:

  • Raising interest in studying the topic, instilling speech culture in chemistry lessons.

Developing:

  • Develop attention, observation, the ability to listen and draw conclusions.

Pedagogical methods and techniques:

  • Perceptive approach.
  • Gnostic approach.
  • cybernetic approach.

Equipment: Interactive board, multimedia, electronic textbooks MarSTU, Internet, collections "Oil and the main products of its processing", "Coal and the most important products of its processing".

During the classes

I. Organizational moment.

I introduce the purpose and objectives of this lesson.

II. Main part.

The most important natural sources of hydrocarbons are: oil, coal, natural and associated petroleum gases.

Oil is “black gold” (I introduce students to the origin of oil, the main reserves, production, composition of oil, physical properties, refined products).

In the process of rectification, oil is divided into the following fractions:

I demonstrate samples of fractions from the collection (demonstration is accompanied by an explanation).

  • Fractionation gases- a mixture of low molecular weight hydrocarbons, mainly propane and butane, with t boiling up to 40 ° C,
  • Gasoline fraction (gasoline)- HC composition C 5 H 12 to C 11 H 24 (bp ​​t 40-200 ° C, with a finer separation of this fraction, gas oil(petroleum ether, 40 - 70°C) and petrol(70 - 120°С),
  • Naphtha fraction- HC composition from C 8 H 18 to C 14 H 30 (bp t 150 - 250 ° C),
  • Kerosene fraction- HC composition from C 12 H 26 to C 18 H 38 (bp t 180 - 300 ° C),
  • Diesel fuel- HC composition from C 13 H 28 to C 19 H 36 (bp t 200 - 350 ° C)

Residue of oil refining - fuel oil- contains hydrocarbons with the number of carbon atoms from 18 to 50. Distillation under reduced pressure from fuel oil is obtained solar oil(S 18 H 28 - S 25 H 52), lubricating oils(S 28 H 58 - S 38 H 78), petrolatum And paraffin– fusible mixtures of solid hydrocarbons. The solid residue of the distillation of fuel oil - tar and products of its processing - bitumen And asphalt used for the manufacture of road surfaces.

The products obtained as a result of oil rectification are subjected to chemical processing. One of them is cracking.

Cracking is the thermal decomposition of petroleum products, which leads to the formation of hydrocarbons with a smaller number of carbon atoms in the molecule. (I use the MarSTU electronic textbook, which tells about the types of cracking).

Students compare thermal and catalytic cracking. (Slide number 16)

Thermal cracking.

The splitting of hydrocarbon molecules proceeds at a higher temperature (470-5500 C). The process proceeds slowly, hydrocarbons with an unbranched chain of carbon atoms are formed. In gasoline obtained as a result of thermal cracking, along with saturated hydrocarbons, there are many unsaturated hydrocarbons. Therefore, this gasoline has a greater knock resistance than straight-run gasoline. Thermal cracking gasoline contains many unsaturated hydrocarbons, which are easily oxidized and polymerized. Therefore, this gasoline is less stable during storage. When it burns, various parts of the engine can become clogged.

catalytic cracking.

The splitting of hydrocarbon molecules proceeds in the presence of catalysts and at a lower temperature (450-5000 C). The focus is on petrol. They try to get more and necessarily better quality. Catalytic cracking appeared precisely as a result of the long-term, stubborn struggle of oilmen to improve the quality of gasoline. Compared to thermal cracking, the process proceeds much faster; in this case, not only the splitting of hydrocarbon molecules occurs, but also their isomerization, i.e. hydrocarbons with a branched chain of carbon atoms are formed. Compared to thermally cracked gasoline, catalytic cracked gasoline has even greater knock resistance.

Coal. (I introduce students to the origin of coal, the main reserves, mining, physical properties, processed products).

Origin: (I use the electronic textbook MarGTU, where they talk about the origin of coal).

Main stocks: (slide number 18) On the map, I show students the largest coal deposits in Russia in terms of production - these are the Tunguska, Kuznetsk, and Pechora basins.

Mining:(I use the MarGTU electronic textbook, where they talk about coal mining).

  • coke oven gas- which includes H 2, CH 4, CO, CO 2, impurities NH 3, N 2 and other gases,
  • Coal tar- contains several hundred different organic substances, including benzene and its homologues, phenol and aromatic alcohols, naphthalene and various heterocyclic compounds,
  • Nadsmolnaya, or ammonia water- contains dissolved ammonia, as well as phenol, hydrogen sulfide and other substances,
  • Coke– solid coking residue, almost pure carbon.

Natural and petroleum associated gases. (I introduce students to the main reserves, production, composition, processed products).

III. Generalization.

In the generalizing part of the lesson, using the Turning Point program, I made a test. The students were armed with remotes. When a question appears on the screen, by pressing the corresponding button, they choose the correct answer.

1. The main components of natural gas are:

  • Ethane;
  • Propane;
  • Methane;
  • Butane.

2. What oil distillation fraction contains from 4 to 9 carbon atoms in a molecule?

  • Naphtha;
  • gas oil;
  • Petrol;
  • Kerosene.

3. What is the meaning of heavy oil cracking?

  • Getting methane;
  • Obtaining gasoline fractions with high detonation resistance;
  • Obtaining synthesis gas;
  • Obtaining hydrogen.

4. Which process does not apply to oil refining?

  • Coking;
  • Fractional distillation;
  • catalytic cracking;
  • Thermal cracking.

5. Which of the following events is the most dangerous for aquatic ecosystems?

  • Violation of the tightness of the oil pipeline;
  • Oil spill as a result of a tanker accident;
  • Violation of technology during deep oil production on land;
  • Transportation of coal by sea.

6. From methane forming natural gas, get:

  • synthesis gas;
  • Ethylene;
  • Acetylene;
  • Butadiene.

7. What features distinguish catalytic cracked gasoline from straight-run gasoline?

  • The presence of alkenes;
  • The presence of alkynes;
  • The presence of hydrocarbons with a branched chain of carbon atoms;
  • High detonation resistance.

The test result is immediately visible on the screen.

Homework:§ 10, exercise 1 - 8

Literature:

  1. L.Yu.Alikberova "Entertaining chemistry" - M.: "AST-Press", 1999.
  2. O.S.Gabrielyan, I.G.Ostroumov “Desk book of a chemistry teacher Grade 10” - M .: “Blik and K”, 2001.
  3. O.S.Gabrielyan, F.N.Maskaev, S.Yu.Ponomarev, V.I.Terenin "Chemistry Grade 10".

The most important sources of hydrocarbons are natural and associated petroleum gases, oil, and coal.

By reserves natural gas the first place in the world belongs to our country. Natural gas contains low molecular weight hydrocarbons. It has the following approximate composition (by volume): 80-98% methane, 2-3% of its closest homologues - ethane, propane, butane and a small amount of impurities - hydrogen sulfide H 2 S, nitrogen N 2 , noble gases, carbon monoxide (IV ) CO 2 and water vapor H 2 O . The composition of the gas is specific to each field. There is the following pattern: the higher the relative molecular weight of hydrocarbon, the less it is contained in natural gas.

Natural gas is widely used as a cheap fuel with high calorific value (combustion of 1m 3 releases up to 54,400 kJ). It is one of the best types of fuel for domestic and industrial needs. In addition, natural gas is a valuable raw material for the chemical industry: the production of acetylene, ethylene, hydrogen, soot, various plastics, acetic acid, dyes, medicines and other products.

Associated petroleum gases are in deposits together with oil: they are dissolved in it and are located above the oil, forming a gas “cap”. When extracting oil to the surface, gases are separated from it due to a sharp drop in pressure. Previously, associated gases were not used and were flared during oil production. Currently, they are captured and used as fuel and valuable chemical raw materials. Associated gases contain less methane than natural gas, but more ethane, propane, butane and higher hydrocarbons. In addition, they contain basically the same impurities as in natural gas: H 2 S, N 2, noble gases, H 2 O vapor, CO 2 . Individual hydrocarbons (ethane, propane, butane, etc.) are extracted from associated gases, their processing makes it possible to obtain unsaturated hydrocarbons by dehydrogenation - propylene, butylene, butadiene, from which rubbers and plastics are then synthesized. A mixture of propane and butane (liquefied gas) is used as a household fuel. Natural gasoline (a mixture of pentane and hexane) is used as an additive to gasoline for better ignition of the fuel when starting the engine. Oxidation of hydrocarbons produces organic acids, alcohols and other products.

Oil- oily flammable liquid of dark brown or almost black color with a characteristic odor. It is lighter than water (= 0.73–0.97 g / cm 3), practically insoluble in water. By composition, oil is a complex mixture of hydrocarbons of various molecular weights, so it does not have a specific boiling point.

Oil consists mainly of liquid hydrocarbons (solid and gaseous hydrocarbons are dissolved in them). Usually these are alkanes (mainly of a normal structure), cycloalkanes and arenes, the ratio of which in oils from various fields varies widely. Ural oil contains more arenes. In addition to hydrocarbons, oil contains oxygen, sulfur and nitrogenous organic compounds.



Crude oil is not normally used. To obtain technically valuable products from oil, it is subjected to processing.

Primary processing oil consists in its distillation. Distillation is carried out at refineries after the separation of associated gases. During the distillation of oil, light oil products are obtained:

gasoline ( t kip \u003d 40–200 ° С) contains hydrocarbons С 5 -С 11,

naphtha ( t kip \u003d 150–250 ° С) contains hydrocarbons С 8 -С 14,

kerosene ( t kip \u003d 180–300 ° С) contains hydrocarbons С 12 -С 18,

gas oil ( t kip > 275 °C),

and in the remainder - a viscous black liquid - fuel oil.

Oil is subjected to further processing. It is distilled under reduced pressure (to prevent decomposition) and lubricating oils are isolated: spindle, engine, cylinder, etc. Petroleum jelly and paraffin are isolated from fuel oil of some grades of oil. The residue of fuel oil after distillation - tar - after partial oxidation is used to produce asphalt. The main disadvantage of oil refining is the low yield of gasoline (no more than 20%).

Oil distillation products have various uses.

Petrol used in large quantities as aviation and automotive fuel. It usually consists of hydrocarbons containing an average of 5 to 9 C atoms in molecules. Naphtha It is used as a fuel for tractors, as well as a solvent in the paint and varnish industry. Large quantities are processed into gasoline. Kerosene It is used as a fuel for tractors, jet planes and rockets, as well as for domestic needs. solar oil - gas oil- used as a motor fuel, and lubricating oils- for lubricating mechanisms. Petrolatum used in medicine. It consists of a mixture of liquid and solid hydrocarbons. Paraffin used to obtain higher carboxylic acids, to impregnate wood in the production of matches and pencils, for the manufacture of candles, shoe polish, etc. It consists of a mixture of solid hydrocarbons. fuel oil in addition to processing into lubricating oils and gasoline, it is used as boiler liquid fuel.

At secondary processing methods oil is a change in the structure of the hydrocarbons that make up its composition. Among these methods, of great importance is the cracking of oil hydrocarbons, which is carried out in order to increase the yield of gasoline (up to 65–70%).

Cracking- the process of splitting hydrocarbons contained in oil, as a result of which hydrocarbons with a smaller number of C atoms in the molecule are formed. There are two main types of cracking: thermal and catalytic.

Thermal cracking is carried out by heating the feedstock (fuel oil, etc.) at a temperature of 470–550 °C and a pressure of 2–6 MPa. In this case, hydrocarbon molecules with a large number of C atoms are split into molecules with a smaller number of atoms of both saturated and unsaturated hydrocarbons. For example:

(radical mechanism),

In this way, mainly automobile gasoline is obtained. Its output from oil reaches 70%. Thermal cracking was discovered by Russian engineer V.G. Shukhov in 1891.

catalytic cracking is carried out in the presence of catalysts (usually aluminosilicates) at 450–500 °C and atmospheric pressure. In this way, aviation gasoline is obtained with a yield of up to 80%. This type of cracking is mainly subjected to kerosene and gas oil fractions of oil. In catalytic cracking, along with cleavage reactions, isomerization reactions occur. As a result of the latter, saturated hydrocarbons with a branched carbon skeleton of molecules are formed, which improves the quality of gasoline:

Catalytic cracked gasoline is of higher quality. The process of obtaining it proceeds much faster, with less consumption of thermal energy. In addition, relatively many branched-chain hydrocarbons (isocompounds) are formed during catalytic cracking, which are of great value for organic synthesis.

At t= 700 °C and above, pyrolysis occurs.

Pyrolysis- decomposition of organic substances without air access at high temperature. During oil pyrolysis, the main reaction products are unsaturated gaseous hydrocarbons (ethylene, acetylene) and aromatic hydrocarbons - benzene, toluene, etc. Since oil pyrolysis is one of the most important ways to obtain aromatic hydrocarbons, this process is often called oil aromatization.

Aromatization– transformation of alkanes and cycloalkanes into arenes. When heavy fractions of petroleum products are heated in the presence of a catalyst (Pt or Mo), hydrocarbons containing 6–8 C atoms per molecule are converted into aromatic hydrocarbons. These processes occur during reforming (upgrading of gasoline).

Reforming- this is the aromatization of gasolines, carried out as a result of heating them in the presence of a catalyst, for example, Pt. Under these conditions, alkanes and cycloalkanes are converted into aromatic hydrocarbons, as a result of which the octane number of gasoline also increases significantly. Aromatization is used to obtain individual aromatic hydrocarbons (benzene, toluene) from gasoline fractions of oil.

In recent years, petroleum hydrocarbons have been widely used as a source of chemical raw materials. Substances necessary for the production of plastics, synthetic textile fibers, synthetic rubber, alcohols, acids, synthetic detergents, explosives, pesticides, synthetic fats, etc. are obtained from them in various ways.

Coal just like natural gas and oil, it is a source of energy and a valuable chemical raw material.

The main method of coal processing is coking(dry distillation). During coking (heating up to 1000 °С - 1200 °С without air access), various products are obtained: coke, coal tar, tar water and coke oven gas (scheme).

Scheme

Coke is used as a reducing agent in the production of iron in metallurgical plants.

Coal tar serves as a source of aromatic hydrocarbons. It is subjected to rectification distillation and benzene, toluene, xylene, naphthalene, as well as phenols, nitrogen-containing compounds, etc. are obtained.

Ammonia, ammonium sulfate, phenol, etc. are obtained from tar water.

Coke oven gas is used to heat coke ovens (combustion of 1 m 3 releases about 18,000 kJ), but it is mainly subjected to chemical processing. So, hydrogen is extracted from it for the synthesis of ammonia, which is then used to produce nitrogen fertilizers, as well as methane, benzene, toluene, ammonium sulfate, and ethylene.