Hydrocarbons and their natural sources briefly. Abstract: Natural sources of hydrocarbons
Message on the topic: “Natural sources of hydrocarbons”
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Hydrocarbons
Hydrocarbons are compounds consisting only of carbon and hydrogen atoms.
Hydrocarbons are divided into cyclic (carbocyclic compounds) and acyclic.
Cyclic (carbocyclic) are compounds that contain one or more cycles consisting only of carbon atoms (in contrast to heterocyclic compounds containing heteroatoms - nitrogen, sulfur, oxygen, etc.).
d.). Carbocyclic compounds, in turn, are divided into aromatic and non-aromatic (alicyclic) compounds.
Acyclic hydrocarbons include organic compounds whose carbon skeleton molecules are open chains.
These chains can be formed by single bonds (alkanes СnН2n+2), contain one double bond (alkenes СnН2n), two or more double bonds (dienes or polyenes), one triple bond (alkynes СnН2n-2).
As you know, carbon chains are part of most organic matter. 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.
Hydrocarbons are the most important type of raw material 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 take a closer look at them.
Oil is 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); in addition to alkanes, it may 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 a dark (brown to black) color with a characteristic odor, insoluble in water. Its density is less than that of water, therefore, when oil gets into it, it spreads over the surface, preventing the dissolution of oxygen and other air gases in the water.
It is obvious that, when oil enters natural bodies of water, it causes the death of microorganisms and animals, leading to environmental disasters and even catastrophes. There are bacteria that can use oil components 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 environmental pollution with oil during its production, transportation and refining.
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 and sulfur-containing compounds and subjected to so-called fractional distillation, or rectification.
Fractional distillation is a physical method of separating a mixture of components with different boiling points.
During the rectification process, oil is divided into the following fractions:
Rectifying gases are 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 C5H12 to C11H24 (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).
The residue from oil distillation - fuel oil - contains hydrocarbons with the number of carbon atoms from 18 to 50. By distillation under reduced pressure from fuel oil, diesel oil (C18H28-C25H52), lubricating oils (C28H58-C38H78), petroleum jelly and paraffin are obtained - low-melting mixtures of solid hydrocarbons.
The solid residue from the distillation of fuel oil - tar and the products of its processing - bitumen and asphalt are used for the manufacture of road surfaces.
Associated petroleum gas
Oil fields contain, as a rule, large accumulations of so-called associated petroleum gas, which collects above the oil in the earth's crust and is partially dissolved 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, whose molecules contain from 1 to 6 carbon atoms. It is obvious that 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. Just a few decades ago, in most oil fields, associated petroleum gas was burned as a useless supplement to oil.
Currently, for example, in Surgut, the richest oil reserve in Russia, the cheapest electricity in the world is generated using associated petroleum gas as fuel.
Associated petroleum gas, compared to natural gas, is richer in composition in various hydrocarbons. Dividing them into fractions, we get:
Gas gasoline is a highly volatile mixture consisting mainly of lenthane and hexane;
A propane-butane mixture, consisting, as the name implies, of propane and butane and easily turning into a liquid state when the pressure increases;
Dry gas is a mixture containing mainly methane and ethane.
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 fuel for internal combustion engines in the Far North and as an additive to motor fuel, making it easier to start engines in winter conditions.
A propane-butane mixture in the form of liquefied gas is used as household fuel (the familiar gas cylinders at your dacha) 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 fuel.
However, the use of associated petroleum gas and its components as fuel is far from the most promising way to use it.
It is much more efficient to use the components of associated petroleum gas as raw materials for chemical production. Hydrogen, acetylene, unsaturated and aromatic hydrocarbons and their derivatives are obtained from alkanes that make up 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
Natural gas is a mixture of gaseous saturated hydrocarbons with a low 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 includes ethane, propane, butane and isobutane, as well as nitrogen and carbon dioxide.
Like associated petroleum, natural gas is used both as a fuel and as a raw material for the production of a variety of 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. Natural gas is used as fuel in power plants, in boiler systems for water heating of residential and industrial buildings, in blast furnace and open-hearth industries.
By striking a match and lighting the gas in the kitchen gas stove of a city house, you “trigger” a chain reaction of oxidation of alkanes that make up natural gas.
Coal
In addition to oil, natural and associated petroleum gases, coal is a natural source of hydrocarbons.
0n forms thick layers in the bowels of the earth, its proven reserves significantly exceed oil reserves. Like oil, coal contains a large amount of various organic substances.
In addition to organic substances, it also contains inorganic substances, such as water, ammonia, hydrogen sulfide and, of course, carbon itself - coal. One of the main methods of processing coal 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 contains hydrogen, methane, carbon dioxide and carbon dioxide, admixtures of ammonia, nitrogen and other gases;
coal tar containing several hundred times-personal organic substances, including benzene and its homologues, phenol and aromatic alcohols, naphthalene and various heterocyclic compounds;
suprasin, or ammonia water, containing, as the name implies, dissolved ammonia, as well as phenol, hydrogen sulfide and other substances;
coke is a solid residue from coking, almost 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 can hardly be overestimated.
Conclusion: thus, oil, associated petroleum and natural gases, and coal are not only the most valuable sources of hydrocarbons, but also part of a unique storehouse of irreplaceable natural resources, the careful and reasonable use of which is a necessary condition for the progressive development of human society.
Natural sources of hydrocarbons are fossil fuels. Most organic substances are obtained from natural sources. In the process of synthesis of organic compounds, natural and accompanying gases, hard and brown coal, oil, oil shale, peat, and products of animal and plant origin are used as raw materials.
What is the composition of natural gas
The qualitative composition of natural gas consists of two groups of components: organic and inorganic.
Organic components include: methane - CH4; propane - C3H8; butane - C4H10; ethane - C2H4; heavier hydrocarbons with more than five carbon atoms. Inorganic components include the following compounds: hydrogen (in small quantities) - H2; carbon dioxide - CO2; helium - He; nitrogen - N2; hydrogen sulfide - H2S.
What exactly the composition of a particular mixture will be depends on the source, that is, the deposit. The same reasons explain the various physical and chemical properties of natural gas.
Chemical composition
The main part of natural gas is methane (CH4) - up to 98%. Natural gas may also contain heavier hydrocarbons:
* ethane (C2H6),
* propane (C3H8),
* butane (C4H10)
- methane homologues, as well as other non-hydrocarbon substances:
* hydrogen (H2),
* hydrogen sulfide (H2S),
* carbon dioxide (CO2),
* nitrogen (N2),
* helium (He).
Natural gas is colorless and odorless.
To identify a leak by smell, a small amount of mercaptans, which have a strong unpleasant odor, is added to the gas.
What are the advantages of natural gas over other types of fuel?
1. simplified extraction (does not require artificial pumping)
2. ready for use without intermediate processing (distillation)
transportation in both gaseous and liquid states.
4. minimal emissions of harmful substances during combustion.
5. convenience of supplying fuel in an already gaseous state during its combustion (lower cost of equipment using this type of fuel)
reserves are more extensive than other fuels (lower market value)
7. use in larger sectors of the national economy than other types of fuel.
a sufficient amount in the depths of Russia.
9. Emissions of the fuel itself during accidents are less toxic to the environment.
10. high combustion temperature for use in technological schemes of the national economy, etc., etc.
Application in the chemical industry
It is used to produce plastics, alcohol, rubber, and organic acids. Only with the use of natural gas can one synthesize chemicals that simply cannot be found in nature, for example, polyethylene.
methane is used as a raw material for the production of acetylene, ammonia, methanol and hydrogen cyanide. At the same time, natural gas is the main raw material base for the production of ammonia. Almost three quarters of all ammonia is used to produce nitrogen fertilizers.
Hydrogen cyanide, obtained from ammonia, together with acetylene serves as the initial raw material for the production of various synthetic fibers. Acetylene can be used to produce various sheet metals, which are widely used in industry and everyday life.
It is also used to produce acetate silk.
Natural gas is one of the best types of fuel used for industrial and domestic needs. Its value as a fuel also lies in the fact that this mineral fuel is quite environmentally friendly. When it burns, much less harmful substances appear when compared with other types of fuel.
The most important petroleum products
During the refining process, petroleum is used to produce fuel (liquid and gaseous), lubricating oils and greases, solvents, individual hydrocarbons - ethylene, propylene, methane, acetylene, benzene, toluene, xylo, etc., solid and semi-solid mixtures of hydrocarbons (paraffin, petroleum jelly , ceresin), petroleum bitumen, carbon black (soot), petroleum acids and their derivatives.
Liquid fuel obtained from oil refining is divided into motor fuel and boiler fuel.
Gaseous fuels include hydrocarbon liquefied fuel gases used for municipal services. These are mixtures of propane and butane in different ratios.
Lubricating oils designed to provide liquid lubrication in various machines and mechanisms are divided depending on the application into industrial, turbine, compressor, transmission, insulating, and motor oils.
Greases are petroleum oils thickened with soaps, solid hydrocarbons and other thickeners.
Individual hydrocarbons obtained from the processing of oil and petroleum gases serve as raw materials for the production of polymers and organic synthesis products.
Of these, the most important are the limiting ones - methane, ethane, propane, butane; unsaturated – ethylene, propylene; aromatic - benzene, toluene, xylenes. Also products of petroleum refining are saturated hydrocarbons with a high molecular weight (C16 and higher) - paraffins, ceresins, used in the perfume industry and as thickeners for greases.
Petroleum bitumen, obtained from heavy oil residues by oxidation, is used for road construction, for the production of roofing materials, for the preparation of asphalt varnishes and printing inks, etc.
One of the main products of oil refining is motor fuel, which includes aviation and motor gasoline.
What are the main natural sources of hydrocarbons that you know?
Natural sources of hydrocarbons are fossil fuels.
Most organic substances are obtained from natural sources. In the process of synthesis of organic compounds, natural and accompanying gases, hard and brown coal, oil, oil shale, peat, and products of animal and plant origin are used as raw materials.
12Next ⇒
Answers to paragraph 19
1. What are the main natural sources of hydrocarbons that you know?
Oil, natural gas, shale, coal.
What is the composition of natural gas? Show on a geographical map the most important deposits: a) natural gas; b) oil; c) coal.
3. What advantages does natural gas have over other types of fuel? For what purposes is natural gas used in the chemical industry?
Natural gas, compared to other sources of hydrocarbons, is the easiest to produce, transport and process.
In the chemical industry, natural gas is used as a source of low molecular weight hydrocarbons.
4. Write the reaction equations for the production of: a) acetylene from methane; b) chloroprene rubber from acetylene; c) carbon tetrachloride from methane.
5. How do associated petroleum gases differ from natural gas?
Associated gases are volatile hydrocarbons dissolved in oil.
Their isolation occurs by distillation. Unlike natural gas, it can be isolated at any stage of oil field development.
6. Describe the main products obtained from associated petroleum gases.
Main products: methane, ethane, propane, n-butane, pentane, isobutane, isopentane, n-hexane, n-heptane, hexane and heptane isomers.
Name the most important petroleum products, indicate their composition and areas of their application.
8. What lubricating oils are used in production?
Motor oils, transmission, industrial, lubricating and cooling emulsions for metal-cutting machines, etc.
How is oil distilled?
10. What is petroleum cracking? Write an equation for the reactions of hydrocarbon splitting And
in this process.
Why is it possible to obtain no more than 20% of gasoline during direct distillation of oil?
Because the content of gasoline fraction in oil is limited.
12. How does thermal cracking differ from catalytic cracking? Give characteristics of thermal and catalytic cracking gasolines.
During thermal cracking, it is necessary to heat the reacting substances to high temperatures; during catalytic cracking, the introduction of a catalyst reduces the activation energy of the reaction, which makes it possible to significantly reduce the reaction temperature.
How can you practically distinguish cracked gasoline from straight distilled gasoline?
Cracking gasoline has a higher octane number compared to straight distilled gasoline, i.e. is more detonation resistant and is recommended for use in internal combustion engines.
14. What is oil aromatization? Write reaction equations that explain this process.
What are the main products obtained from coking coal?
Naphthalene, anthracene, phenanthrene, phenols and coal oils.
16. How is coke obtained and where is it used?
Coke is a solid, porous, gray product obtained by coconut coal at temperatures of 950-1100 without oxygen.
It is used for smelting cast iron, as a smokeless fuel, a reducing agent for iron ore, and a disintegrant for charge materials.
17. What are the main products received:
a) from coal tar; b) from tar water; c) from coke oven gas? Where are they used? What organic substances can be obtained from coke oven gas?
a) benzene, toluene, naphthalene – chemical industry
b) ammonia, phenols, organic acids – chemical industry
c) hydrogen, methane, ethylene - fuel.
Remember all the main methods for producing aromatic hydrocarbons. What are the differences between the methods for producing aromatic hydrocarbons from the products of coking coal and oil? Write the equations for the corresponding reactions.
They differ in the methods of production: primary oil refining is based on the difference in the physical properties of various fractions, and coking is based purely on the chemical properties of coal.
Explain how, in the process of solving energy problems in the country, the ways of processing and using natural hydrocarbon resources will be improved.
Search for new energy sources, optimization of oil production and refining processes, development of new catalysts to reduce the cost of entire production, etc.
20. What are the prospects for producing liquid fuel from coal?
In the future, producing liquid fuel from coal is possible, provided that the costs of its production are reduced.
Task 1.
It is known that the gas contains in volume fractions 0.9 methane, 0.05 ethane, 0.03 propane, 0.02 nitrogen. What volume of air will be required to burn 1 m3 of this gas under normal conditions?
Task 2.
What volume of air (no.s.) is needed to burn 1 kg of heptane?
Task 3. Calculate what volume (in l) and what mass (in kg) of carbon monoxide (IV) will be obtained upon combustion of 5 mol of octane (no.).
The main sources of hydrocarbons on our planet are natural gas, oil And coal. The most stable of hydrocarbons, saturated and aromatic, have survived millions of years of preservation in the bowels of the earth.
Natural gas consists mainly of methane with admixtures of other gaseous alkanes, nitrogen, carbon dioxide and some other gases; coal contains mainly polycyclic aromatic hydrocarbons.
Oil, unlike natural gas and coal, contains a whole range of components:
Other substances are also present in oil: heteroatomic organic compounds (contain sulfur, nitrogen, oxygen and other elements), water with salts dissolved in it, solid particles of other rocks and other impurities.
Interesting to know! Hydrocarbons are also found in space, including on other planets.
For example, methane makes up a significant part of Uranus's atmosphere and is responsible for its light turquoise color observed through a telescope. The atmosphere of Titan, Saturn's largest moon, consists mainly of nitrogen, but also contains the hydrocarbons methane, ethane, propane, ethylene, propyne, butadiine and their derivatives; sometimes methane rains there, and hydrocarbon rivers flow into hydrocarbon lakes on the surface of Titan.
The presence of unsaturated hydrocarbons, along with saturated and molecular hydrogen, is due to the effects of solar radiation.
Mendeleev owns the phrase: “Burning oil is the same as heating a furnace with banknotes.” Thanks to the emergence and development of oil refining technologies, in the 20th century it turned from a common fuel into the most valuable source of raw materials for the chemical industry.
Petroleum products are currently used in almost all industries.
Primary oil refining is preparation, that is, purification of oil from inorganic impurities and petroleum gas dissolved in it, and distillation, that is, physical division into factions depending on the boiling point:
From the fuel oil remaining after the distillation of oil at atmospheric pressure, components of high molecular weight are separated under the influence of vacuum, suitable for processing into mineral oils, motor fuels and other products, and the remainder - tar- used for the production of bitumen.
In the process of secondary oil refining, individual fractions are subjected to chemical transformations.
These are cracking, reforming, isomerization and many other processes that make it possible to obtain unsaturated and aromatic hydrocarbons, branched alkanes and other valuable petroleum products. Some of them are spent on the production of high-quality fuel and various solvents, and some are raw materials for the production of new organic compounds and materials for a wide variety of industries.
But it should be remembered that hydrocarbon reserves in nature are replenished much more slowly than humanity consumes them, and the process of refining and burning petroleum products itself introduces strong deviations into the chemical balance of nature.
Of course, sooner or later nature will restore balance, but this can result in serious problems for humans. Therefore it is necessary new technologies to eliminate the use of hydrocarbons as fuel in the future.
To solve such global problems it is necessary development of fundamental science and a deep understanding of the world around us.
Hydrocarbons are of great economic importance, since they serve as the most important type of raw material for the production of almost all products of the modern organic synthesis industry and are widely used for energy purposes. They seem to accumulate solar heat and energy, which are released when burned. Peat, coal, oil shale, oil, natural and associated petroleum gases contain carbon, the combination of which with oxygen during combustion is accompanied by the release of heat.
coal | peat | oil | natural gas |
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solid | solid | liquid | gas |
without smell | without smell | Strong smell | without smell |
homogeneous composition | homogeneous composition | mixture of substances | mixture of substances |
a dark-colored rock with a high content of flammable substances resulting from the burial of accumulations of various plants in sedimentary strata | accumulation of half-rotted plant matter accumulated at the bottom of swamps and overgrown lakes | natural flammable oily liquid, consisting of a mixture of liquid and gaseous hydrocarbons | a mixture of gases formed in the bowels of the Earth during the anaerobic decomposition of organic substances, the gas belongs to the group of sedimentary rocks |
Calorific value - the number of calories released when burning 1 kg of fuel | |||
7 000 - 9 000 | 500 - 2 000 | 10000 - 15000 | ? |
Coal.
Coal has always been a promising raw material for producing energy and many chemical products.
The first major consumer of coal since the 19th century was transport, then coal began to be used for the production of electricity, metallurgical coke, the production of various products through chemical processing, carbon-graphite structural materials, plastics, rock wax, synthetic, liquid and gaseous high-calorie fuels, high-nitrous acids for the production fertilizers
Coal is a complex mixture of high-molecular compounds, which include the following elements: C, H, N, O, S. Coal, like oil, contains a large number of various organic substances, as well as inorganic substances, such as water, ammonia, hydrogen sulfide and of course carbon itself - coal.
Coal processing occurs in three main directions: coking, hydrogenation and incomplete combustion. One of the main methods of processing coal is coking– calcination without air access in coke ovens at a temperature of 1000–1200°C. At this temperature, without access to oxygen, coal undergoes complex chemical transformations, resulting in the formation of coke and volatile products:
1. coke oven gas (hydrogen, methane, carbon monoxide and carbon dioxide, admixtures of ammonia, nitrogen and other gases);
2. coal tar (several hundred different organic substances, including benzene and its homologues, phenol and aromatic alcohols, naphthalene and various heterocyclic compounds);
3. tar, or ammonia, water (dissolved ammonia, as well as phenol, hydrogen sulfide and other substances);
4. coke (solid coking residue, almost pure carbon).
The cooled coke is sent to metallurgical plants.
When volatile products (coke oven gas) are cooled, coal tar and ammonia water condense.
By passing non-condensed products (ammonia, benzene, hydrogen, methane, CO 2, nitrogen, ethylene, etc.) through a solution of sulfuric acid, ammonium sulfate is released, which is used as a mineral fertilizer. Benzene is absorbed into the solvent and distilled from the solution. After this, the coke oven gas is used as fuel or as a chemical raw material. Coal tar is obtained in small quantities (3%). But, given the scale of production, coal tar is considered as a raw material for the production of a number of organic substances. If you remove products boiling at 350°C from the resin, what remains is a solid mass - pitch. It is used to make varnishes.
Hydrogenation of coal is carried out at a temperature of 400–600°C under a hydrogen pressure of up to 25 MPa in the presence of a catalyst. This produces a mixture of liquid hydrocarbons, which can be used as motor fuel. Production of liquid fuel from coal. Liquid synthetic fuel is high-octane gasoline, diesel and boiler fuel. To obtain liquid fuel from coal, it is necessary to increase its hydrogen content through hydrogenation. Hydrogenation is carried out using multiple circulation, which allows you to convert the entire organic mass of coal into liquid and gases. The advantage of this method is the possibility of hydrogenating low-grade brown coal.
Coal gasification will make it possible to use low-quality brown and hard coal in thermal power plants without polluting the environment with sulfur compounds. This is the only method for producing concentrated carbon monoxide (carbon monoxide) CO. Incomplete combustion of coal produces carbon (II) monoxide. Using a catalyst (nickel, cobalt) at normal or increased pressure, gasoline containing saturated and unsaturated hydrocarbons can be obtained from hydrogen and CO:
nCO + (2n+1)H 2 → C n H 2n+2 + nH 2 O;
nCO + 2nH 2 → C n H 2n + nH 2 O.
If dry distillation of coal is carried out at 500–550°C, then tar is obtained, which, along with bitumen, is used in the construction industry as a binding material in the manufacture of roofing and waterproofing coatings (roofing felt, roofing felt, etc.).
In nature, hard coal is found in the following regions: Moscow Region, South Yakutsk Basin, Kuzbass, Donbass, Pechora Basin, Tunguska Basin, Lena Basin.
Natural gas.
Natural gas is a mixture of gases, the main component of which is methane CH 4 (from 75 to 98% depending on the field), the rest is ethane, propane, butane and a small amount of impurities - nitrogen, carbon monoxide (IV), hydrogen sulfide and vapors water, and, almost always, hydrogen sulfide and organic petroleum compounds - mercaptans. It is they that give the gas a specific unpleasant odor, and when burned, lead to the formation of toxic sulfur dioxide SO 2 .
Typically, the higher the molecular weight of a hydrocarbon, the less of it is found in natural gas. The composition of natural gas from different fields is not the same. Its average composition in percentage by volume is as follows:
CH 4 | C 2 H 6 | C 3 H 8 | C 4 H 10 | N 2 and other gases |
75-98 | 0,5 - 4 | 0,2 – 1,5 | 0,1 – 1 | 1-12 |
Methane is formed during anaerobic (without access to air) fermentation of plant and animal residues, therefore it is formed in bottom sediments and is called “swamp” gas.
Deposits of methane in hydrated crystalline form, the so-called methane hydrate discovered under a layer of permafrost and at great depths in the oceans. At low temperatures (−800ºC) and high pressures, methane molecules are located in the voids of the crystal lattice of water ice. In the ice voids of one cubic meter of methane hydrate, 164 cubic meters of gas are “canned.”
Chunks of methane hydrate look like dirty ice, but in air they burn with a yellow-blue flame. It is estimated that the planet stores between 10,000 and 15,000 gigatons of carbon in the form of methane hydrate (“giga” equals 1 billion). Such volumes are many times greater than all currently known natural gas reserves.
Natural gas is a renewable natural resource, as it is synthesized in nature continuously. It is also called "biogas". Therefore, many environmental scientists today associate the prospects for the prosperous existence of mankind with the use of gas as an alternative fuel.
As a fuel, natural gas has great advantages over solid and liquid fuels. Its heat of combustion is much higher, when burned it does not leave ash, and the combustion products are much cleaner environmentally. Therefore, about 90% of the total volume of extracted natural gas is burned as fuel in thermal power plants and boiler houses, in thermal processes in industrial enterprises and in everyday life. About 10% of natural gas is used as a valuable raw material for the chemical industry: for the production of hydrogen, acetylene, soot, various plastics, and medicines. Methane, ethane, propane and butane are separated from natural gas. Products that can be obtained from methane are of great industrial importance. Methane is used for the synthesis of many organic substances - synthesis gas and further synthesis of alcohols based on it; solvents (carbon tetrachloride, methylene chloride, etc.); formaldehyde; acetylene and soot.
Natural gas forms independent deposits. The main deposits of natural combustible gases are located in Northern and Western Siberia, the Volga-Ural basin, the North Caucasus (Stavropol), the Komi Republic, the Astrakhan region, and the Barents Sea.
Remember: distillation (distillation) is a method of separating a mixture of volatile liquids by gradual evaporation followed by condensation.
Oil. Oil distillation
Many of the organic substances you deal with in everyday life—plastics, paints, detergents, drugs, varnishes, solvents—are synthesized from hydrocarbons. There are three main sources of hydrocarbons in nature - oil, natural gas and coal.
Oil is one of the most important mineral resources. It is impossible to imagine our life without oil and its products. It is not for nothing that oil-rich countries play an important role in the global economy.
Oil is a dark, oily liquid found in the earth's crust (Fig. 29.1). It is a homogeneous mixture of several hundred substances - mainly saturated hydrocarbons with the number of carbon atoms in the molecule from 1 to 40.
To process this mixture, both physical and chemical methods are used. First, oil is separated into simple mixtures - fractions - by distillation (distillation or rectification), based on the fact that various substances in the oil boil at different temperatures (Table 12). Distillation occurs in a distillation column under significant heating (Fig. 29.2). Fractions with the highest boiling points, decomposing at high temperatures, are distilled under reduced pressure.
Table 12. Oil distillation fractions
Number of carbon atoms in molecules |
Boiling point, °C |
Application |
|
Over 200 o C |
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Automotive fuel |
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Fuel, raw materials for synthesis |
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Aviation gasoline |
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Diesel fuel |
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Heavy gas oil (fuel oil) |
Fuel for thermal power plants |
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Decomposes when heated, distilled under reduced pressure |
Production of asphalt, bitumen, paraffin, lubricants, fuel for boiler houses |
Ukraine is quite rich in oil reserves. The main fields are concentrated in three oil and gas regions: eastern (Sumy, Poltava, Chernihiv and Kharkov regions), western (Lviv and Ivano-Frankivsk regions) and southern (Black Sea region, shelves of the Azov and Black Seas). Oil reserves in Ukraine are estimated at about 2 billion tons, but a significant part of them is concentrated at great depths (5-7 km). Annual oil production in Ukraine is about 2 million tons with a demand of 16 million tons, so, unfortunately, Ukraine is still forced to import significant volumes of oil.
Chemical refining of petroleum products
Some petroleum distillation products can be used immediately, without further processing, such as gasoline and kerosene, but they make up only 20-30% of oil. In addition, after distillation, gasoline is of low quality (with a low octane number, i.e., when compressed in the engine, it explodes rather than burns). An engine running on such fuel makes a characteristic knocking noise and quickly fails. To improve the quality of gasoline and increase its yield, oil is subjected to chemical processing.
One of the most important methods of chemical oil refining is cracking (from the English to crack - to split, break, since during cracking the carbon chains are broken) (Fig. 29.3). When heated to 500 °C without air access in the presence of special catalysts, long alkane molecules are split into smaller ones. When cracking saturated hydrocarbons, a mixture of light saturated and unsaturated hydrocarbons is formed, for example:
Thanks to this process, the yield of gasoline and kerosene increases. This type of gasoline is sometimes called cracked gasoline.
One of the characteristics that determines the quality of gasoline is the octane number, which indicates the possibility of detonation (explosion) of the fuel-air mixture in the engine. The higher the octane number, the lower the likelihood of detonation, and therefore the higher the quality of gasoline. Heptane is unsuitable as a motor fuel; it is more likely to detonate, while isooctane (2,2,4-trimethylpentane) has the opposite properties - it almost does not detonate in the engine. These two substances became the basis for the scale for determining the quality of gasoline - the octane number scale. On this scale, heptane received a value of 0, and isooctane - 100. According to this scale, gasoline with an octane rating of 95 has the same knocking properties as a mixture of 95% isooctane and 5% heptane.
Oil refining occurs at special enterprises - oil refineries. There they carry out both rectification of crude oil and chemical processing of the resulting petroleum products. There are six oil refineries in Ukraine: in Odessa, Kremenchug, Kherson, Lisichansk, Nadvornyansk and Drohobych. The total capacity of all Ukrainian oil refining enterprises exceeds 52 million tons per year.
Natural gas
The second most important source of hydrocarbons is natural gas, the main component of which is methane (93-99%). Natural gas is used primarily as an efficient fuel. When it burns, neither ash nor poisonous carbon monoxide is formed, so natural gas is considered an environmentally friendly fuel.
Large quantities of natural gas are used by the chemical industry. Processing of natural gas is reduced mainly to the production of unsaturated hydrocarbons and synthesis gas. Ethylene and acetylene are formed by the elimination of hydrogen from lower alkanes:
Synthesis gas - a mixture of carbon(II) oxide and hydrogen - is produced by heating methane with water steam:
From this mixture, using different catalysts, oxygen-containing compounds are synthesized - methyl alcohol, acetic acid, etc.
When passed over a cobalt catalyst, the synthesis gas is converted into a mixture of alkanes, which is synthetic gasoline:
Coal
Another source of hydrocarbons is coal. In the chemical industry it is processed by coking - heating to 1000 ° C without air access (Fig. 29.5, p. 170). In this case, coke and coal tar are formed, the mass of which is only a few percent of the mass of coal. Coke is used as a reducing agent in metallurgy (for example, to obtain iron from its oxides).
Coal tar contains several hundred organic compounds, mainly aromatic hydrocarbons, which are obtained from it by distillation.
Coal is also used as fuel, but this poses major environmental problems. Firstly, coal contains non-flammable impurities, which turn into slag during fuel combustion; secondly, coal contains small amounts of Sulfur and Nitrogen compounds, the combustion of which produces oxides that pollute the atmosphere. Ukraine ranks one of the first in the world in terms of coal reserves. On an area equal to 0.4% of the world's territory, Ukraine contains about 5% of the world's reserves of energy raw materials, 95% of which is coal (about 54 billion tons). In 2015, coal production amounted to 40 million tons, which is almost half as much as in 2011. Today there are 300 coal mines in Ukraine, and 40% of them produce coking coal (which can be processed into coke). Production is concentrated mainly in the Donetsk, Lugansk, Dnepropetrovsk and Volyn regions.
Linguistic task
In Greek, pyro means "fire" and lysis means "decomposition." Why do you think the terms “cracking” and “pyrolysis” are often used interchangeably?
Key idea
The main sources of hydrocarbons for industry are oil, coal and natural gas. For more effective use, these natural resources must be processed to isolate individual substances or mixtures.
Control questions
334. Name the main natural sources of hydrocarbons.
335. What is the physical method of separating oil into fractions based on?
336. What fractions is oil divided into during distillation? Describe their use. Which petroleum product is the most valuable for modern society?
337. How do the most important petroleum products differ in chemical composition?
338. Using information from this and previous paragraphs, describe the use of natural gas in the chemical industry.
339. What are the main products produced by coking coal?
340. Why is coal heated during processing without air access?
341. Why is natural gas better than coal as a fuel?
342. What substances and materials are produced by processing coal and natural gas?
Assignments for mastering the material
343. In the process of cracking the hydrocarbon C 20 H 42, two products are formed with the same number of Carbon atoms in the molecules. Write an equation for the reaction.
344. What is the fundamental difference between oil cracking and rectification?
345. Why do you think that during direct distillation of oil it is not possible to process more than 20% of it into gasoline?
346. Analyze fig. 29.2 and describe how petroleum distillation occurs.
347. Write down equations for the reactions of producing ethylene and acetylene from natural gas components.
348. One of the components of gasoline is the hydrocarbon C 8 H 18. Write an equation for the reaction of its production from carbon(I) oxide and hydrogen.
349. When gasoline burns completely, carbon dioxide and water are formed in the engine. Write an equation for the combustion reaction of gasoline, assuming that it consists of hydrocarbons of the composition C 8 H 18.
350. Car exhaust gases contain toxic substances: carbon(N) oxide and nitrogen(N) oxide. Explain what chemical reactions resulted in their formation.
351. How many times will the volume of the fuel-air mixture, consisting of 40 ml of octane vapor and 3 liters of air, increase when ignited? When making calculations, assume that the air contains 20% oxygen (by volume).
352. Gasoline sold in warm climates consists of hydrocarbons with a higher molecular weight than gasoline sold in cold climates. Guess why oil refiners do this.
353*. Oil contains so many valuable organic substances that D.I. Mendeleev said: “Burning oil in a furnace is almost the same as burning with banknotes.” How do you understand this statement? Suggest ways to rationally use natural sources of hydrocarbons.
354*. In additional sources, find information about materials and substances whose raw materials are oil, natural gas or coal. Can they be made without using natural sources of hydrocarbons? Is it possible for humanity to stop using these materials? Justify your answer.
355*. Using the knowledge gained in geography lessons in grades 8 and 9, describe the current and promising basins and areas of coal, oil, and natural gas production in Ukraine. Are the locations of processing plants for these hydrocarbon sources coordinated with their deposits?
This is textbook material
Origin of fossil fuels.
In addition to the fact that all living organisms are composed of organic substances, the main sources of organic compounds are: oil, coal, natural and associated petroleum gases.
Oil, coal and natural gas are sources of hydrocarbons.
These natural resources are used:
· As a fuel (source of energy and heat) – this is conventional combustion;
· In the form of raw materials for further processing – this is organic synthesis.
Theories of the origin of organic substances:
1- Theory of organic origin.
According to this theory, the deposits were formed from the remains of extinct plant and animal organisms, which turned into a mixture of hydrocarbons in the thickness of the earth's crust under the influence of bacteria, high pressure and temperature.
2- Theory of mineral (volcanic) origin of oil.
According to this theory, oil, coal and natural gas were formed during the primary stage of the formation of planet Earth. In this case, the metals combined with carbon to form carbides. As a result of the reaction of carbides with water vapor in the depths of the planet, gaseous hydrocarbons were formed, in particular methane and acetylene. And under the influence of heat, radiation and catalysts, other compounds contained in oil were formed from them. In the upper layers of the lithosphere, liquid oil components evaporated, the liquid thickened, turned into asphalt and then into coal.
This theory was first expressed by D.I. Mendeleev, and then in the 20th century, the French scientist P. Sabatier simulated the described process in the laboratory and obtained a mixture of hydrocarbons similar to oil.
Main component natural gas is methane. It also contains ethane, propane, butane. The higher the molecular weight of the hydrocarbon, the less of it is contained in natural gas.
Application: When natural gas burns, it releases a lot of heat, so it serves as an energy-efficient and cheap fuel in industry. Natural gas is also 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 gases are found in nature above oil or dissolved in it under pressure. Previously, associated petroleum gases were not used; they were burned. Currently, they are captured and used as fuel and valuable chemical raw materials. Associated gases contain less methane than natural gas, but they contain significantly more of its homologues. Associated petroleum gases are separated to a narrower composition.
For example: gas gasoline - a mixture of pentane, hexane and other hydrocarbons is added to gasoline to improve engine starting; propane-butane fraction in the form of liquefied gas is used as fuel; dry gas - similar in composition to natural gas - is used to produce acetylene, hydrogen, and also as fuel. Sometimes associated petroleum gases are subjected to more thorough separation and individual hydrocarbons are extracted from them, from which unsaturated hydrocarbons are then obtained.
One of the most common types of fuel and raw material for organic synthesis remains coal. What types of coal are there, where does coal come from and what products is it used to produce - these are the main questions that we will consider in today’s lesson. Coal began to be used as a source of chemicals earlier than oil and natural gas.
Coal is not an individual substance. Its composition includes: free carbon (up to 10%), organic substances containing, in addition to carbon and hydrogen, oxygen, sulfur, nitrogen, minerals that remain in the form of slag when burning coal.
Coal is a solid combustible mineral of organic origin. According to the biogenic hypothesis, it was formed from dead plants as a result of the vital activity of microorganisms in the Carboniferous period of the Paleozoic era (about 300 million years ago). Coal is cheaper than oil, it is more evenly distributed in the earth's crust, its natural reserves far exceed those of oil and, according to scientists, will not be exhausted for another century.
The formation of coal from plant residues (coalification) occurs in several stages: peat – brown coal – hard coal – anthracite.
The process of carbonification consists of a gradual increase in the relative content of carbon in organic matter as a result of its depletion in oxygen and hydrogen. The formation of peat and brown coal occurs as a result of the biochemical decomposition of plant residues without access to oxygen. The transition of brown coal to stone occurs under the influence of elevated temperatures and pressures associated with mountain-forming and volcanic processes.
Material overview
Material overview
Integrated lesson in chemistry and geography in the 10th grade on the topic "Natural sources of hydrocarbons"
“...You can drown with banknotes”
DI. Mendeleev
Equipment: Geographic maps of mineral resources of Russia and the world, maps “Fuel Industry of the World”, “Mineral Resources of the World”, textbook maps, atlases, textbook tables, statistical material. collections “Fuel”, “Oil and its products”, “Minerals”, multimedia installation, tables “Oil distillation products”, “Distillation column”, “Recycling of oil...”, “Harmful impact on the environment.. "
Lesson objectives:
1.Repeat the placement of hydrocarbon deposits on the territory of Russia and the world.
2. Generalize knowledge about natural sources of hydrocarbons: their composition, physical properties, methods of production, processing.
3. Consider the prospects for changing the structure of the fuel and energy complex (alternative energy sources).
Teaching methods: story, lecture, conversation, demonstration of collections,independent work with a geographical map, atlas.
The topic “Natural sources of hydrocarbons” is now more relevant than ever. The development of hydrocarbon deposits poses many problems for society. These are primarily social problems associated with the development of hard-to-reach areas where there is no social structure. Harsh conditions require the development of new technologies for the extraction and transportation of raw materials. The export of crude oil products, the lack of a developed industrial base for their processing, and the lack of oil products on the domestic Russian market are economic and political problems. Environmental problems associated with the production, transportation, and processing of hydrocarbons. Human society is forced to look for ways to solve all these problems. It is important to learn to make decisions, make choices, and be responsible for the results of your activities.
During the classes
On the students' desks are collections of solid fuels and minerals, atlases, and geography textbooks.
The chemistry teacher begins the lesson by telling students about the importance of gas and oil not only as sources of energy, but also as raw materials for the chemical industry. Then the question of the advantage of gaseous fuel over solid fuel is discussed with students. During the discussion, conclusions are formulated and written down.
Chemistry teacher
The main natural sources of hydrocarbons are:
Natural and associated petroleum gases
Oil
Coal
Natural and associated petroleum gases differ in their occurrence in nature, composition and application.
Let's look at the composition of natural gas.
Composition of natural gas.
СН4 93 - 98% С4Н10 0.1 - 1%
C2H6 0.5 - 4% C5H12 0 - 1%
C3H8 0.2 - 1.5% N2 2 - 13%
and other gases.
As we can see, the main part of natural gas is methane.
Associated petroleum gas contains significantly less methane (30-50%), but more of its closest homologues: ethane. propane, butane, pentane (up to 20% each) and other saturated hydrocarbons. Natural gas fields are usually found close to oil fields; Apparently, natural gas (as well as associated petroleum gas) was formed due to the breakdown of oil hydrocarbons as a result of the activity of anaerobic bacteria.
Natural and associated petroleum gases are cheap fuel and valuable chemical raw materials. The most important type of gaseous fuel is natural gas, cheap and high-calorie (up to 39,700 kJ), since its main component is methane (up to 93-98%).
Why do you think natural gas is used as a gaseous fuel?
Gaseous fuel has significant advantages over solid fuel:
mixes easily and completely with air, so when burning it, only a small excess of air is required for complete combustion;
the gas can be preheated in special generators to obtain a higher flame temperature;
the design of fireboxes is much simpler, since there is no slag or ash during combustion;
the absence of smoke has a beneficial effect on sanitary and hygienic environmental conditions; environmental cleanliness;
Gaseous fuel can be transmitted through gas pipelines.
Cheapness;
High calorific value
For this reason, gaseous fuel is increasingly used in industry, everyday life and vehicles and is one of the best types of fuel for domestic and industrial needs.
In the second half of the 20th century, world gas production increased more than 10 times and continues to grow. Until recently, gas was produced mainly in developed countries, but recently the role of Asian and African countries has been growing. The undisputed leader in gas reserves and production is Russia. 15-20% of extracted raw materials enter the world market
Students are asked questions:
1. Where do you think fuel resources are used?
After the students’ answers, the teacher summarizes and once again gives a definition of the fuel and energy complex. Then tasks are offered. (work in small groups, reading maps, tables, diagrams. Partial search work)
Task 1: Using table No. 4 of the textbook, familiarize yourself with the world production of the main types of fuel (oil and gas production).
Task 2: Using Figure 23, get acquainted with the shift in the structure of world consumption of fuel resources and answer the question: is gas consumption growing in the world? (The answer is yes)
In the course of discussing the data in Table No. 4 and Figure 23, students come to the conclusion that there are several most important oil and gas production areas. The teacher shows and names the main oil and gas production areas on a geographical map, students compare them with their atlases, name the countries and write them down in their notebooks.
The total number of oil fields is about 50 thousand. However, at the current level of production, let's calculate the resource availability of humanity.
In your notebook: Remember the calculation formula (R = W/D)
In what units is resource availability expressed? (of the year). Draw a conclusion! (few)
There are countries in the world that have enormous oil reserves. Using the table, name the 3 countries with the largest reserves. Where does Russia rank?
Many countries are producing oil. In each region, several countries can be identified as leaders in production. Using the map, name these countries and write them down in your notebook
In Europe: In Asia: In America: In Africa:
Where exactly are the largest oil fields located? Here are just some of them.
1 barrel of oil is equal to 158.988 liters, 1 barrel per day – 50 tons per year
More than 680 thousand tons of oil per day were produced in Gavar, in addition to 56.6 million m³ per day of natural gas.
Agajari operates 60 flowing wells, annual production is 31.4 million tons
There are 484 flowing wells in operation in Greater Burgan, with annual production of about 70 million tons
What is a shelf?
Do you think production from the shelf is cheaper or more expensive than on the mainland? Why?
Which countries are highlighted on the map? What do they have in common? What is the name of this organization? Her main task?
Oil is actively sold on the world market. (40%) Stable ties have developed between countries, so-called “oil bridges”. What are the most important of them? How would you explain their existence? How is oil transported?
The largest tanker is 500 meters long. Takes on board up to 500,000 tons of oil.
Supertankers are the product of the scientific and technological revolution of our time. The word itself comes from the English word “tank” - tank. A sea tanker is a vessel designed to transport liquid cargo (oil, acid, vegetable oil, molten sulfur, etc.) in ship tanks (tanks). Supertankers can carry 50 percent more oil on a single voyage than others, and have only 15 percent more operating costs for bunkering, crew, and insurance, allowing oil companies chartering the vessel to increase their profits and save savings. There will always be a demand for such oil tankers.
One of the representatives of this class of sea vessels was the oil tanker Batillus. This cargo ship was created, from start to finish, according to the original design without additional modernization during operation. It was built in 10 months, and approximately 70,000 tons of steel were used for construction. Construction cost the owner $130 million
Middle East: countries around the Persian Gulf (Saudi Arabia, United Arab Emirates, Iran, Iraq). This region accounts for 2/3 of world oil production.
North America: Alaska, Texas.
Northern and Western Africa: Algeria, Libya, Nigeria, Egypt.
South America: northern mainland, Venezuela.
Europe: shelf of the North and Norwegian seas.
Russia (Western Siberia): Tomsk and Tyumen regions.
Task 3: Using Figure 24, determine the leading countries in oil production; Using Figure 25, determine the formation of sustainable oil bridges between countries.
CONCLUSION: Oil and gas production is carried out mainly in developing countries, consumption - in developed ones.
The chemistry teacher continues.
A significant increase in the production of high-calorie and cheaper types of fuel (oil and gas) has led to a sharp decrease in the share of solid fuel in the fuel balance of countries.
Associated petroleum gas is also (by origin) natural gas. It owes its name to oil, with which it occurs in nature. Associated petroleum gas is dissolved in oil (partially), and is partially located above it, forming a gas dome. Under the pressure of this gas, oil rises through the well to the surface. When the pressure decreases, associated petroleum gas easily leaves the oil.
For a long time, associated petroleum gas was not used and was burned on site. Currently, it is captured and used as fuel or as one of the sources for organic synthesis, since it contains a large number of methane homologues. For more rational use, associated petroleum gas is divided into fractions.
Gas fractions: 1. C5H12, C6H14 and other liquids - gas gasoline;
2. C3H8, C4H10 - propane-butane mixture
3. CH4, C2H6 and other impurities - “dry gas”
Used as gasoline additives;
As fuel and as household gas;
In organic synthesis and as a fuel.
We are born and live in a world of products and things derived from oil. In the history of mankind there were Stone and Iron periods. Who knows, maybe historians will call our period oil or plastic. Oil is the most titled type of minerals. She is called both the “queen of energy” and the “queen of fertility.” And her kingship in organic chemistry is “black gold.” Oil created a new industry - petrochemistry, and it also gave rise to a number of environmental problems.
Oil has been known to mankind since ancient times. On the banks of the Euphrates it was mined 6-7 thousand years BC. e. It was used for lighting homes and for embalming. 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 used mainly for street lighting.
In the early 19th century in Russia, petroleum was distilled into a lighting oil called kerosene, which was used in lamps invented in the mid-19th century. During the same period, due to the growth of industry and the advent of steam engines, the demand for oil as a source of lubricants began to increase. Introduction in the late 60s. 19th century oil drilling is considered the birth of the oil industry.
At the turn of the 19th and 20th centuries, gasoline and diesel engines were invented. This led to the rapid development of oil production and methods of its processing.
Oil is a “clump of energy”. Using just 1 ml of this substance, 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 to extract 1 mg of nuclear fuel, tons of rocks must be processed.
Deposits of crude oil and gas arose 100-200 million years ago in the thickness of the Earth. The origin of oil is one of nature's hidden secrets.
Oil and petroleum products.
Oil is the only liquid fossil fuel. Oily liquid from yellow to dark brown, lighter than water. (oil samples are demonstrated.) There are light and heavy oils. The lungs are extracted using pumps, using the fountain method, and are mainly used to make gasoline and kerosene. Heavy ones are sometimes even mined using the mine method (Yaremskoye deposit in the Komi Republic) and processed into bitumen, fuel oil, and oils.
Unlike other minerals, oil, like gas, does not form separate layers; it fills voids in rocks: pores between grains of sand, cracks.
Oil is flammable. It retains this property even when on the surface of water, where it can ignite from a flammable torch until it spreads into a thin iridescent film. Oil is a unique fuel, its calorific value is 37-49 MJ/kg. Thus, 10 tons of oil provide the same amount of heat as 13 tons of anthracite and 31 tons of firewood. It is the basis of the energy and chemical industries. Medicinal oil rich in naphthenic and aromatic hydrocarbons is also known.
Laboratory experiment No. 1. Physical properties of oil
We examine a test tube with oil (oil liquid, dark brown in color, almost black with a characteristic odor.)
Oil does not smell like gasoline, which is what the idea of it is associated with. The aroma of oil is given by the accompanying carbon disulfide and the remains of plant and animal organisms.
Dissolve oil in water (it does not dissolve, a film forms on the surface). The density of the film is less than water, so it is on the surface.
Elemental composition of oil.
C – 84 – 87% O, N, S - 0.5 – 2%
H – 12 – 14% in some deposits up to 5% S
Oil is a complex mixture of a large number of organic compounds.
Composition of oil and its products.
Petroleum refining (chemistry)
Oil refining is a process that involves the creation of complex equipment.
Teacher: fill out the table “Oil refining”
Primary processing (physical processes) |
Cleaning |
Dehydration, desalting, distillation of volatile hydrocarbons (mainly methane) |
Distillation |
Thermal separation of oil into fractions. based on the difference in boiling points of hydrocarbons having different molecular weights |
|
Recycling (chemical processes) |
Cracking |
The breakdown of long-chain hydrocarbons and the formation of hydrocarbons with fewer carbon atoms in the molecules |
Reforming |
Changing the structure of hydrocarbon molecules by: Isomerization, alkylation, Cyclization (flavoring) |
Primary oil refining - rectification - separation into oil fractions based on the difference in boiling points.
Oil is fed into the distillation column through a tubular furnace, in which it is heated to 350⁰C. In the form of steam, oil rises up the column and, gradually cooling, is divided into fractions: gasoline, naphtha, kerosene, diesel oil, fuel oil. The non-distillable part is tar.
(the table describes the operation of the distillation column, names the fractions and their areas of application).
Oil fractions:
C5 – C11 - gasoline (fuel for cars and aircraft, solvent);
C8 - C14 – naphtha (fuel for tractors);
C12 – C18 – kerosene (fuel for tractors, rockets, airplanes);
С15 – С22 – gas oil (light oil products) – diesel. fuel.
The distillation residue is fuel oil (fuel for boiler houses). Additional distillations produce lubricating oils. The use of fuel oil is diesel oil, paraffin, petroleum jelly, lubricating oils. Application of tar – bitumen, asphalt.
Secondary oil refining: cracking (catalytic and thermal).
thermal |
catalytic |
450–550° |
400-500 °C, cat. Al2O3 nSiO2 (aluminosilicates catalyst) |
The process is slow |
The process is fast |
Many unsaturated hydrocarbons are formed |
Significantly less unsaturated hydrocarbons are formed |
Gasoline produced: 1) resistant to detonation 2) unstable during storage (unsaturated hydrocarbons are easily oxidized) |
Gasoline produced: 1) resistant to detonation 2) more stable during storage (since there are a lot of unsaturated hydrocarbons) |
С16Н34 → С8Н18 + С8Н16 СH₃- CH₂- CH₂- CH₃ → CH₃- CH- CH₃
CH₃
The brand of gasoline and its quality depend on its knock resistance on the octane scale:
Detonation resistance is taken as 0 (easily ignites spontaneously)
n. heptane;
Over 100 – (high stability) 2,2,4-trimethylpentane. The more n.heptane contained in gasoline, the higher its grade.
Branched saturated hydrocarbons, unsaturated and aromatic hydrocarbons are resistant to detonation.
Reforming (aromatization) - 450⁰ - 540⁰С
hexane → cyclohexane → benzene: C₆H₁₄ → C₆H₁₂ → C₆H₆
They are produced to increase the detonation resistance of gasoline - the ability to withstand strong compression in the engine cylinder at high temperatures without spontaneous combustion.
Geography teacher continues lesson
Distribution of major oil reserves in the world.
The word "oil" appeared in Russian in the 17th century and comes from the Arabic "nafata", which means "to spew". That's what they called it in 4-3 thousand BC. e. the inhabitants of Mesopotamia, the ancient center of civilization, a flammable oily black liquid, which indeed sometimes erupts onto the surface of the earth in the form of fountains.
Therefore, from ancient times until the mid-19th century, oil was extracted where it flowed in the form of springs, passing through faults and cracks in rocks. But when they began to look for it far from the places of direct oil output, questions arose: how to do this? where to drill wells?
In the course of long geological studies, it was found that oil is most likely to be found where thick layers of sedimentary cover are folded and torn apart by tectonic movements of the earth's crust, forming dome-shaped bends of the layers, the so-called anticlinal type of natural accumulation of hydrocarbons, called a reservoir. Areas of the earth's crust containing one or more such deposits are called deposits.
More than 27 thousand oil fields have been discovered in the world, but only a small part of them (1%) contains ¾ of the world's oil reserves, and 33 supergiants contain half of the world's reserves.
Analyzing the distribution of the world's proven oil resources by region and country, we come to the conclusion that South-West Asia plays an exceptional role, namely, 2/3 of the world's oil resources lie in the countries of the Persian Gulf (SA, Iraq, UAE, Kuwait, Iran).
I propose, using the data, to complete task No. 1 (mark on the contour map the top 10 countries in the world in terms of proven oil resources).
Fuel industry in the world economy.
Refineries that process oil and various types of fuel (gasoline, kerosene, fuel oil) are located mainly in areas of consumption. Therefore, a huge territorial gap has formed in the world economy between the areas of its production and consumption. Let's find out why?
Currently, oil is produced in more than 80 countries around the world. World production (approaching 3.5 billion tons) is distributed approximately equally between economically developed and developing countries.
Slightly more than 40% falls on OPEC countries, and among some large regions, Foreign Asia especially stands out, primarily thanks to the Gulf countries.
Let's analyze the data, so the Gulf countries account for 2/3 of the world's proven oil reserves and about 1/3 of its global production. 4 countries in this region produce more than 100 million tons of oil per year each, with SA leading the list, ranking 1st in the world. The remaining regions according to the size of oil production are distributed in the following order: Latin America, North America, Africa, CIS, Northern Europe. At the same time, most of the energy resources, primarily oil, produced in developing countries are exported to the USA, Western Europe, and Japan, which will always experience a high dependence on fuel imports in industry.
As a result, stable “energy bridges” were formed between many countries and continents - in the form of powerful, primarily oceanic, oil cargo flows.
Thus, the leading oil exporters currently remain OPEC countries (almost OPEC 2/3 of world exports), Mexico and Russia. From here, the most powerful oil export traffic flows are in the following directions:
Reinforcing the proposed material, complete task No. 2 on contour maps. Note the main oil cargo flows.
Russian technologist and designer – Shukhov V.G.;
made (1878) calculations for the first oil pipeline in Russia and supervised its construction. Received (1891) a patent for the creation of an oil hydrocarbon cracking installation;
By the beginning of the 80s, about 16 million tons of oil entered the ocean annually, which accounted for 10.23% of world production. The greatest oil losses are associated with its transportation from production areas. Emergency situations involving tankers discharging washing and ballast water overboard, all of this causes the presence of constant amounts of pollution along sea routes.
Over the past 130 years, since 1964, about 12,000 wells have been drilled in the World Ocean, of which 11,000 and 1,350 industrial wells have been equipped in the North Sea alone. Due to minor leaks, 10.1 million tons of oil are lost annually. Large quantities of oil enter the seas through rivers and industrial wastewater. Once in the marine environment, oil first spreads in the form of a film, forming layers of varying thickness. The oil film changes the composition of the spectrum and the intensity of light penetration into water. When mixed with water, oil forms two types of emulsion: direct “oil in water” and reverse “water in oil”. Direct emulsions, composed of oil droplets with a diameter of up to 10.5 microns, are less stable and are characteristic of oil containing surfactants. When volatile fractions are removed, oil forms viscous inverse emulsions that can remain on the surface, be transported by currents, washed ashore and settle to the bottom.
November 13, 2002 A tanker loaded with oil sinks off the coast of Spain. There are 77 thousand tons of oil in the holds of the tanker.
By the time the tanker sank, about 5 thousand tons of fuel oil and diesel fuel used to run the tanker’s engines had spilled into the sea, and about the same amount spilled when the tanker split into two parts. In the area of the disaster, two giant oil spills formed, the area of which was more than 100 square kilometers. The waves throw more and more portions of fuel oil onto the shore, and, as far as the eye can see, a strip of poisonous black-brown color lies along the entire coast. The black surf contrasts hideously with the green shrubs of the coastal area.
The fish become coated in oil and die from suffocation. Seabirds - loons, gulls, guillemots, cormorants - trample on the stones. They are cold, their chest, neck, wings are covered with oil, poisonous muck penetrates into the body when they try to clean their feathers with their beaks. Not understanding anything, they look at their native element, which has become alien to them, sadly, as if anticipating imminent death. The birds are resignedly handed over to enthusiasts who try to clean the oil from their plumage and use pipettes to drop the saving solution into their beady eyes. But only a few hundred of the thousands of dying birds can be helped. Irreparable damage has been caused to one of the richest fishing regions of the country. Unique places for collecting oysters, mussels, catching octopus and crabs have been polluted.
chemistry teacher
Oil purification
Methods to combat oil in the ocean:
a) self-destruction, b) chemical dispersion, c) absorption, d) fencing, e) biological treatment.
A - the oil slick is small and far from the shore (dissolution in water and evaporation)
B - chemical preparations (absorb oil, pull it into small spots and remove it with nets)
B - straw or peat absorbs small spots in calm conditions
G - fencing with “containers” and pumping out of them with pumps
D - biological drugs
To reduce harm to nature, it is necessary:
improve methods and technologies for oil production, storage, and transportation and ensure production safety.
Fossil coals are solid products of the alteration of ancient plant remains, used in industry in the form of fuel and also as chemical raw materials. They are distinguished by ash content. If the ash content is below 50%, it is coal; if it is higher, it is oil shale.
Coal contains 60-98% carbon, 1-12% hydrogen, 2-20% oxygen, 1-3% nitrogen, sulfur, phosphorus, silicon, aluminum, iron, moisture
Based on the composition of the starting material, coals are divided into humic (formed from higher plants) and sapropelic (formed from algae). Peat or sapropel gradually, under pressure and in the absence of oxygen, turns into brown coal, which turns into hard coal, and then into anthracite. Under specific geological conditions (strong pressure, high temperature), coal can turn into graphite and shungite - rocks containing cryptocrystalline carbon.
Brown coals are loose formations of brown or black-brown color. They contain 64-78% carbon, up to 6% hydrogen. They have low thermal conductivity. These are low quality coals. The largest reserves of brown coal are concentrated in the Lena and Kansk-Achinsk basins of Russia (working with a geographical map)
Stone coals are very dense. They contain 90% carbon, up to 5% hydrogen (work with the “Coals” diagram (Appendix 1)). They have a high calorific value. From them, through processing, you can get more than 400 different products, the cost of which increases by 20-25 times compared to the cost of coal itself. Coal is processed at coke plants. A very promising direction of processing is the production of liquid fuel from coal.
Fuel. chemical raw materials
Geography teacher
The largest coal basins are Tunguska, Lensky, Taimyr in Russia; Appalachian in the USA, Russian in Germany, Karaganda basin in Kazakhstan (working with a geographical map).
Anthracite contains the most carbon - up to 97% (working with the “Coals” diagram), therefore it is used as a high-quality smokeless fuel, as well as in metallurgy, the chemical and electrical industries.
Look at the coals in the collection and note that the higher the carbon content in the substance, the more intense its color, the higher the quality of the coal.
Students look at brown coal, bituminous coal, and anthracite in the “Fuel” collection
How are coals mined?
Coal is mined in two ways: open-pit and underground. The open method is more progressive and economical, since it allows the use of technology. This method is used mainly to extract thermal coals. The underground method is more expensive, but also more promising, since the highest quality coals are found at great depths. Today this is how coal is mined for metallurgy.
Which country ranks 1st in terms of proven coal reserves? (USA)
Chemistry teacher
DI. Mendeleev, who celebrated his 175th birthday this year, wrote on this issue: “There is no waste, there are unused raw materials.”
Thus, oil, gas, coal are not only the most valuable sources of hydrocarbons, but also part of a unique storehouse of irreplaceable natural resources, the careful and reasonable use of which is a necessary condition for the progressive development of human society. On this occasion, we return once again to the epigraph of our lesson - the words of the great Russian chemist D.I. Mendeleev, who said that “Oil is not a fuel; you can burn it with banknotes.” This statement can be applied to all natural hydrocarbons.
Reinforcing the material learned
1. What products are isolated from associated petroleum gas and what are they used for?
Answer: Gasoline is separated from associated petroleum gas,which is used as an additive to regular gasoline;propane-butane fraction is used asfuel; dry gas is used in organic reactionssynthesis.
2. Why is natural gas easier to ignite in an engine than regular gasoline?
Answer: Gas gasoline has a lower temperatureignition than usual.
3. Why can’t the composition of oil be expressed in one formula?
Answer: The composition of oil cannot be expressed in one formula, because...oil is a mixture of many hydrocarbons.
Homework:
1. Read according to the textbook § 20 – 22 (before cracking of petroleum products)
2. Questions and assignments: No. 4 § 20, No. 7 – 9 § 21
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