During the lesson you will be able to study the topic “Natural sources of hydrocarbons. Oil refining". More than 90% of all energy currently consumed by humanity is obtained from fossil natural organic compounds. You will learn about natural resources (natural gas, oil, coal), what happens to oil after its extraction.
Topic: Saturated hydrocarbons
Lesson: Natural Sources of Hydrocarbons
About 90% of the energy consumed by modern civilization is generated by burning natural fossil fuels - natural gas, oil and coal.
Russia is a country rich in reserves natural fossil fuels. There are large reserves of oil and natural gas in Western Siberia and the Urals. Coal is mined in the Kuznetsk, South Yakutsk basins and other regions.
Natural gas consists on average of 95% methane by volume.
In addition to methane, natural gas from various fields contains nitrogen, carbon dioxide, helium, hydrogen sulfide, as well as other light alkanes - ethane, propane and butanes.
Natural gas is extracted from underground deposits where it is under high pressure. Methane and other hydrocarbons are formed from organic substances of plant and animal origin during their decomposition without access to air. Methane is constantly being formed as a result of the activity of microorganisms.
Methane discovered on planets solar system and their companions.
Pure methane has no odor. However, the gas used in everyday life has a characteristic bad smell. This is what special additives smell like - mercaptans. The smell of mercaptans allows you to detect a domestic gas leak in time. Mixtures of methane with air are explosive in a wide range of ratios - from 5 to 15% gas by volume. Therefore, if you smell gas in a room, you should not only light a fire, but also not use electrical switches. The slightest spark can cause an explosion.
Rice. 1. Oil from different fields
Oil- a thick liquid similar to oil. Its color ranges from light yellow to brown and black.
Rice. 2. Oil fields
Oil from different fields varies greatly in composition. Rice. 1. The main part of oil is hydrocarbons containing 5 or more carbon atoms. Basically, these hydrocarbons are classified as limiting, i.e. alkanes. Rice. 2.
Oil also contains organic compounds containing sulfur, oxygen, nitrogen. Oil contains water and inorganic impurities.
Gases that are released during its production are dissolved in oil - associated petroleum gases. These are methane, ethane, propane, butanes with admixtures of nitrogen, carbon dioxide and hydrogen sulfide.
Coal, like oil, is a complex mixture. The share of carbon in it accounts for 80-90%. The rest is hydrogen, oxygen, sulfur, nitrogen and some other elements. In brown coal the proportion of carbon and organic matter is lower than in stone. Even less organic matter in oil shale.
In industry, coal is heated to 900-1100 0 C without air access. This process is called coking. The result is coke with a high carbon content, necessary for metallurgy, coke oven gas and coal tar. Many organic substances are released from gas and tar. Rice. 3.
Rice. 3. Construction of a coke oven
Natural gas and oil are the most important sources of raw materials for the chemical industry. Oil as it is extracted, or “crude oil,” is difficult to use even as fuel. Therefore, crude oil is divided into fractions (from the English “fraction” - “part”), using differences in the boiling points of its constituent substances.
Oil separation method based on different temperatures boiling of its constituent hydrocarbons is called distillation or distillation. Rice. 4.
Rice. 4. Petroleum products
The fraction that distills from approximately 50 to 180 0 C is called gasoline.
Kerosene boils at temperatures of 180-300 0 C.
A thick black residue containing no volatile substances is called fuel oil.
There are also a number of intermediate fractions that boil in narrower ranges - petroleum ethers (40-70 0 C and 70-100 0 C), white spirit (149-204 ° C), and gas oil (200-500 0 C). They are used as solvents. Fuel oil can be distilled under reduced pressure to produce lubricating oils and paraffin. Solid residue from fuel oil distillation - asphalt. It is used for the production of road surfaces.
Processing of associated petroleum gases is a separate industry and produces a number of valuable products.
Summing up the lesson
During the lesson you studied the topic “Natural sources of hydrocarbons. Oil refining". More than 90% of all energy currently consumed by humanity is obtained from fossil natural organic compounds. You learned about natural resources (natural gas, oil, coal), what happens to oil after its extraction.
Bibliography
1. Rudzitis G.E. Chemistry. Fundamentals of general chemistry. 10th grade: textbook for general education institutions: a basic level of/ G. E. Rudzitis, F. G. Feldman. - 14th edition. - M.: Education, 2012.
2. Chemistry. Grade 10. Profile level: academic. for general education institutions/ V.V. Eremin, N.E. Kuzmenko, V.V. Lunin et al. - M.: Bustard, 2008. - 463 p.
3. Chemistry. Grade 11. Profile level: academic. for general education institutions/ V.V. Eremin, N.E. Kuzmenko, V.V. Lunin et al. - M.: Bustard, 2010. - 462 p.
4. Khomchenko G.P., Khomchenko I.G. Collection of problems in chemistry for those entering universities. - 4th ed. - M.: RIA "New Wave": Publisher Umerenkov, 2012. - 278 p.
Homework
1. No. 3, 6 (p. 74) Rudzitis G.E., Feldman F.G. Chemistry: Organic chemistry. 10th grade: textbook for general education institutions: basic level / G. E. Rudzitis, F.G. Feldman. - 14th edition. - M.: Education, 2012.
2. How does associated petroleum gas differ from natural gas?
3. How is oil distilled?
The most important natural sources of hydrocarbons are oil , natural gas And coal . They form rich deposits in various regions of the Earth.
Previously, extracted natural products were used exclusively as fuel. Currently, methods for their processing have been developed and are widely used, making it possible to isolate valuable hydrocarbons, which are used both as high-quality fuel and as raw materials for various organic syntheses. Processes natural sources of raw materials petrochemical industry . Let's look at the main methods of processing natural hydrocarbons.
The most valuable source of natural raw materials is oil . It is an oily liquid of dark brown or black color with a characteristic odor, practically insoluble in water. Oil density is 0.73–0.97 g/cm3. Oil is a complex mixture of various liquid hydrocarbons in which gaseous and solid hydrocarbons are dissolved, and the composition of oil from different fields may differ. Alkanes, cycloalkanes, aromatic hydrocarbons, as well as oxygen-, sulfur- and nitrogen-containing organic compounds may be present in oil in varying proportions.
Crude oil is practically not used, but is processed.
Distinguish primary oil refining (distillation ), i.e. dividing it into fractions with different boiling points, and recycling (cracking ), during which the structure of hydrocarbons is changed
dovs included in its composition.
Primary oil refining is based on the fact that the higher the boiling point of hydrocarbons, the higher their molar mass. Oil contains compounds with boiling points from 30 to 550°C. As a result of distillation, oil is divided into fractions that boil at different temperatures and contain mixtures of hydrocarbons with different molar masses. These fractions have a variety of uses (see Table 10.2).
Table 10.2. Products of primary oil refining.
| Fraction | Boiling point, °C | Compound | Application |
| Liquefied gas | <30 | Hydrocarbons C 3 -C 4 | Gaseous fuels, raw materials for the chemical industry |
| Gasoline | 40-200 | Hydrocarbons C 5 – C 9 | Aviation and automobile fuel, solvent |
| Naphtha | 150-250 | Hydrocarbons C 9 – C 12 | Diesel fuel, solvent |
| Kerosene | 180-300 | Hydrocarbons C 9 -C 16 | Fuel for diesel engines, household fuel, lighting fuel |
| Gas oil | 250-360 | Hydrocarbons C 12 -C 35 | Diesel fuel, feedstock for catalytic cracking |
| Fuel oil | > 360 | Higher hydrocarbons, O-, N-, S-, Me-containing substances | Fuel for boiler plants and industrial furnaces, raw materials for further distillation |
Fuel oil accounts for about half the mass of oil. Therefore, it is also subjected to thermal processing. To prevent decomposition, fuel oil is distilled under reduced pressure. In this case, several fractions are obtained: liquid hydrocarbons, which are used as lubricating oils ; mixture of liquid and solid hydrocarbons – petrolatum , used in the preparation of ointments; mixture of solid hydrocarbons – paraffin , used for the production of shoe polish, candles, matches and pencils, as well as for impregnating wood; non-volatile residue - tar , used to produce road, construction and roofing bitumen.
Oil recycling involves chemical reactions that change the composition and chemical structure of hydrocarbons. Its variety is
ty – thermal cracking, catalytic cracking, catalytic reforming.
Thermal cracking usually subject to fuel oil and other heavy fractions of oil. At a temperature of 450-550°C and a pressure of 2–7 MPa, hydrocarbon molecules are split by the free radical mechanism into fragments with a smaller number of carbon atoms, and saturated and unsaturated compounds are formed:
S 16 H 34 ¾® S 8 H 18 + S 8 H 16
C 8 H 18 ¾®C 4 H 10 +C 4 H 8
This method is used to obtain motor gasoline.
Catalytic cracking carried out in the presence of catalysts (usually aluminosilicates) at atmospheric pressure and temperature 550 - 600°C. At the same time, aviation gasoline is produced from kerosene and gas oil fractions of oil.
The breakdown of hydrocarbons in the presence of aluminosilicates occurs according to the ionic mechanism and is accompanied by isomerization, i.e. the formation of a mixture of saturated and unsaturated hydrocarbons with a branched carbon skeleton, for example:
CH 3 CH 3 CH 3 CH 3 CH 3
cat., t||
C 16 H 34 ¾¾® CH 3 -C -C-CH 3 + CH 3 -C = C - CH-CH 3
Catalytic reforming carried out at a temperature of 470-540°C and a pressure of 1–5 MPa using platinum or platinum-rhenium catalysts deposited on an Al 2 O 3 base. Under these conditions, the transformation of paraffins and
cycloparaffins petroleum into aromatic hydrocarbons
cat., t, p
¾¾¾¾® + 3Н 2
cat., t, p
C 6 H 14 ¾¾¾¾® + 4H 2
Catalytic processes make it possible to obtain gasoline of improved quality due to its high content of branched and aromatic hydrocarbons. The quality of gasoline is characterized by its octane number. The more the mixture of fuel and air is compressed by the pistons, the greater the engine power. However, compression can only be carried out to a certain limit, above which detonation (explosion) occurs.
gas mixture, causing overheating and premature engine wear. Normal paraffins have the lowest resistance to detonation. With a decrease in chain length, an increase in its branching and the number of double
It increases in the number of connections; it is especially high in aromatic hydrocarbons
before giving birth. To assess the resistance to detonation of various types of gasoline, they are compared with similar indicators for the mixture isooctane And n-hep-tana with different ratios of components; octane number equal to the percentage of isooctane in this mixture. The higher it is, the higher the quality of gasoline. The octane number can also be increased by adding special anti-knock agents, for example, tetraethyl lead Pb(C 2 H 5) 4, however, such gasoline and its combustion products are toxic.
In addition to liquid fuel, catalytic processes produce lower gaseous hydrocarbons, which are then used as raw materials for organic synthesis.
Another important natural source of hydrocarbons, the importance of which is constantly increasing, is natural gas. It contains up to 98% vol. methane, 2–3% vol. its closest homologues, as well as impurities of hydrogen sulfide, nitrogen, carbon dioxide, noble gases and water. Gases released during oil production ( passing ), contain less methane, but more of its homologues.
Natural gas is used as fuel. In addition, individual saturated hydrocarbons are isolated from it by distillation, as well as synthesis gas , consisting mainly of CO and hydrogen; they are used as raw materials for various organic syntheses.
Mined in large quantities coal – heterogeneous solid material of black or gray-black color. It is a complex mixture of various high molecular weight compounds.
Coal is used as a solid fuel and is also subjected to coking – dry distillation without air access at 1000-1200°C. As a result of this process, the following are formed: coke , which is finely ground graphite and is used in metallurgy as a reducing agent; coal tar , which is distilled to produce aromatic hydrocarbons (benzene, toluene, xylene, phenol, etc.) and pitch used for the preparation of roofing felt; ammonia water And coke oven gas , containing about 60% hydrogen and 25% methane.
Thus, natural sources of hydrocarbons provide
the chemical industry with a variety of and relatively cheap raw materials for carrying out organic syntheses, which make it possible to obtain numerous organic compounds that are not found in nature, but are necessary for humans.
The general scheme of using natural raw materials for basic organic and petrochemical synthesis can be presented as follows.
Arenas Synthesis gas Acetylene AlkenesAlkanes
Basic organic and petrochemical synthesis
Test tasks.
1222. What is the difference between primary oil refining and secondary refining?
1223. What compounds determine high quality gasoline?
1224. Suggest a method that makes it possible to obtain ethyl alcohol from oil.
During the lesson you will be able to study the topic “Natural sources of hydrocarbons. Oil refining". More than 90% of all energy currently consumed by humanity is obtained from fossil natural organic compounds. You will learn about natural resources (natural gas, oil, coal), what happens to oil after its extraction.
Topic: Saturated hydrocarbons
Lesson: Natural Sources of Hydrocarbons
About 90% of the energy consumed by modern civilization is generated by burning natural fossil fuels - natural gas, oil and coal.
Russia is a country rich in natural fossil fuel reserves. There are large reserves of oil and natural gas in Western Siberia and the Urals. Coal is mined in the Kuznetsk, South Yakutsk basins and other regions.
Natural gas consists on average of 95% methane by volume.
In addition to methane, natural gas from various fields contains nitrogen, carbon dioxide, helium, hydrogen sulfide, as well as other light alkanes - ethane, propane and butanes.
Natural gas is extracted from underground deposits where it is under high pressure. Methane and other hydrocarbons are formed from organic substances of plant and animal origin during their decomposition without access to air. Methane is constantly being formed as a result of the activity of microorganisms.
Methane has been discovered on the planets of the solar system and their satellites.
Pure methane has no odor. However, the gas used in everyday life has a characteristic unpleasant odor. This is what special additives smell like - mercaptans. The smell of mercaptans allows you to detect a domestic gas leak in time. Mixtures of methane with air are explosive in a wide range of ratios - from 5 to 15% gas by volume. Therefore, if you smell gas in a room, you should not only light a fire, but also not use electrical switches. The slightest spark can cause an explosion.
Rice. 1. Oil from different fields
Oil- a thick liquid similar to oil. Its color ranges from light yellow to brown and black.
Rice. 2. Oil fields
Oil from different fields varies greatly in composition. Rice. 1. The main part of oil is hydrocarbons containing 5 or more carbon atoms. Basically, these hydrocarbons are classified as limiting, i.e. alkanes. Rice. 2.
Oil also contains organic compounds containing sulfur, oxygen, nitrogen. Oil contains water and inorganic impurities.
Gases that are released during its production are dissolved in oil - associated petroleum gases. These are methane, ethane, propane, butanes with admixtures of nitrogen, carbon dioxide and hydrogen sulfide.
Coal, like oil, is a complex mixture. The share of carbon in it accounts for 80-90%. The rest is hydrogen, oxygen, sulfur, nitrogen and some other elements. In brown coal the proportion of carbon and organic matter is lower than in stone. Even less organic matter in oil shale.
In industry, coal is heated to 900-1100 0 C without air access. This process is called coking. The result is coke with a high carbon content, necessary for metallurgy, coke oven gas and coal tar. Many organic substances are released from gas and tar. Rice. 3.
Rice. 3. Construction of a coke oven
Natural gas and oil are the most important sources of raw materials for the chemical industry. Oil as it is extracted, or “crude oil,” is difficult to use even as fuel. Therefore, crude oil is divided into fractions (from the English “fraction” - “part”), using differences in the boiling points of its constituent substances.
The method of separating oil based on the different boiling points of its constituent hydrocarbons is called distillation or distillation. Rice. 4.
Rice. 4. Petroleum products
The fraction that distills from approximately 50 to 180 0 C is called gasoline.
Kerosene boils at temperatures of 180-300 0 C.
A thick black residue containing no volatile substances is called fuel oil.
There are also a number of intermediate fractions that boil in narrower ranges - petroleum ethers (40-70 0 C and 70-100 0 C), white spirit (149-204 ° C), and gas oil (200-500 0 C). They are used as solvents. Fuel oil can be distilled under reduced pressure to produce lubricating oils and paraffin. Solid residue from fuel oil distillation - asphalt. It is used for the production of road surfaces.
Processing of associated petroleum gases is a separate industry and produces a number of valuable products.
Summing up the lesson
During the lesson you studied the topic “Natural sources of hydrocarbons. Oil refining". More than 90% of all energy currently consumed by humanity is obtained from fossil natural organic compounds. You learned about natural resources (natural gas, oil, coal), what happens to oil after its extraction.
Bibliography
1. Rudzitis G.E. Chemistry. Fundamentals of general chemistry. 10th grade: textbook for general education institutions: basic level / G. E. Rudzitis, F.G. Feldman. - 14th edition. - M.: Education, 2012.
2. Chemistry. Grade 10. Profile level: academic. for general education institutions/ V.V. Eremin, N.E. Kuzmenko, V.V. Lunin et al. - M.: Bustard, 2008. - 463 p.
3. Chemistry. Grade 11. Profile level: academic. for general education institutions/ V.V. Eremin, N.E. Kuzmenko, V.V. Lunin et al. - M.: Bustard, 2010. - 462 p.
4. Khomchenko G.P., Khomchenko I.G. Collection of problems in chemistry for those entering universities. - 4th ed. - M.: RIA "New Wave": Publisher Umerenkov, 2012. - 278 p.
Homework
1. No. 3, 6 (p. 74) Rudzitis G.E., Feldman F.G. Chemistry: Organic chemistry. 10th grade: textbook for general education institutions: basic level / G. E. Rudzitis, F.G. Feldman. - 14th edition. - M.: Education, 2012.
2. How does associated petroleum gas differ from natural gas?
3. How is oil distilled?
Disputes about the shape of the Earth do not diminish the importance of its contents. The most important resource has always been groundwater. They provide a priority need human body. However, without fossil fuels, which are the main supplier of energy for human civilization, human life seems completely different.
Fuel is a source of energy
Among all the fossils hidden in the depths of the Earth, fuel belongs to the combustible (or sedimentary) type.
The base is hydrocarbon, so one of the effects of the combustion reaction is the release of energy, which can easily be used to improve the comfort of human life. Behind last decade About 90% of all energy used on Earth was produced using fossil fuels. This fact gives us a lot to think about, given that the riches of the planet’s interior are non-renewable energy sources and are depleted over time.
Fuel types
Main fuels |
|||
hard | liquid | gaseous | dispersed |
The suppliers of all fossil fuels are oil, coal and natural gas.
Brief use as fuel
The raw materials for the production of energy resources are oil, coal, oil shale, natural gas, gas hydrates, and peat.
Oil- a liquid related to combustible (sedimentary) fossils. Consists of hydrocarbons and other chemical elements. The color of the liquid, depending on the composition, varies between light brown, dark brown and black. Compositions of yellow-green and colorless color are rarely found. The presence of nitrogen, sulfur and oxygen-containing elements in oil determines its color and smell.
Coal- name of Latin origin. Carbō is the international name for carbon. The composition contains bitumen masses and plant remains. This is an organic compound that has become the object of slow decomposition under the influence of external factors (geological and biological).
Oil shale, like coal, are a representative of the group of solid combustible fossils, or caustobiolites (which literally translated from Greek sounds like “combustible life stone”). During dry distillation (under the influence of high temperatures) it forms resins that are similar in nature chemical composition to oil. The composition of shale is dominated by minerals(calcide, dolomite, quartz, pyrite, etc.), but there are also organic ones (kerogen), which only in high-quality rocks reach 50% of the total composition.
Natural gas- a gaseous substance formed during the decomposition of organic substances. In the bowels of the Earth there are three types of accumulation of mixtures of gases: individual accumulations, gas caps of oil fields and as part of oil or water. At optimal climatic conditions the substance is only in a gaseous state. It may be found in the bowels of the earth in the form of crystals (natural gas hydrates).
Gas hydrates- crystalline formations formed from water and gas under certain conditions. They belong to the group of compounds of variable composition.
Peat- loose rock used as fuel, thermal insulation material, fertilizer. It is a gas-bearing mineral and is used as fuel in many regions.
Origin
Everything, that modern man extracts from the bowels of the earth and is a non-renewable natural resource. It took millions of years and special geological conditions for their appearance. A large number of fossil fuels formed in the Mesozoic.
Oil- according to the biogenic theory of its origin, formation lasted for hundreds of millions of years from organic substances of sedimentary rocks.
Coal- is formed when decaying plant material is replenished faster than its decomposition occurs. Swamps are a suitable place for such a process. Standing water protects the layer of plant mass from complete destruction by bacteria due to its low oxygen content. Coal is divided into humic (comes from the remains of wood, leaves, stems) and sapropelite (formed mainly from algae).
The raw material for the formation of coal can be called peat. If it is immersed under layers of sediment, water and gases are lost under compression and coal is formed.
Oil shale- the organic component is formed using biochemical transformations of the simplest algae. Divided into two types: thallomoalginite (contains algae with intact cellular structure) and colloalginite (algae with loss of cellular structure).
Natural gas- according to the same theory of the biogenic origin of fossils, natural gas is formed at higher pressure and temperature readings than oil, which is proven by the deeper occurrence of deposits. They are formed from the same natural material(remains of living organisms).
Gas hydrates- these are formations whose appearance requires special thermobaric conditions. Therefore, they are formed mainly on sea bottom sediments and frozen rocks. They can also form on the walls of pipes during gas production, and therefore the fossil is heated to a temperature above hydrate formation.
Peat- formed in swamp conditions from incompletely decomposed organic plant remains. Deposited on the soil surface.
Production
Coal and natural gas differ not only in the way they rise to the surface. Gas deposits are located deeper than others - from one to several kilometers deep. The substance is located in the pores of reservoirs (a layer containing natural gas). The force that forces the substance to rise upward is the pressure difference in the underground formations and the collection system. Extraction occurs using wells, which they try to distribute evenly throughout the entire field. Fuel extraction thus avoids gas flows between sites and untimely watering of deposits.
Oil and gas production technologies have some similarities. Types of oil production are distinguished by methods of raising the substance to the surface:
- fountain (a technology similar to gas, based on the difference in pressure underground and in the liquid delivery system);
- gas lift;
- using an electric centrifugal pump;
- with installation of an electric screw pump;
- rod pumps (sometimes connected to a ground pump).
The extraction method depends on the depth of the substance. There are a huge number of options for bringing oil to the surface.
The method of developing a coal deposit also depends on the characteristics of the occurrence of coal in the soil. Open-pit mining is carried out when the fossil is found at a level of one hundred meters from the surface. Often produced mixed type production: first open method, then underground (using faces). Coal deposits are rich in other resources of consumer significance: these are valuable metals, methane, rare metals, The groundwater.
Shale deposits are developed either by mining (considered to be ineffective) or by in situ mining, which involves heating the rock underground. Due to the complexity of the technology, production is carried out in very limited quantities.
Peat is extracted by draining swamps. Due to the appearance of oxygen, aerobic microorganisms are activated, decomposing its organic matter, which leads to the release of carbon dioxide at enormous speed. Peat is the cheapest type of fuel; its extraction is carried out constantly in compliance with certain rules.
Recoverable reserves
One of the assessments of society's well-being is based on fuel consumption per capita: the higher the consumption, the more comfortable people live. This fact (and not only) forces humanity to increase the volume of fuel production, affecting pricing. The price of oil today is determined by such an economic term as “netback”. This term implies a price that includes the weighted average cost of petroleum products (produced from the purchased substance) and delivery of raw materials to the enterprise.
Trading exchanges sell oil at CIF prices, which literally translates to “cost, insurance and freight.” From this we can conclude that the price of oil today based on transaction quotes includes the price of raw materials and transportation costs for its delivery.
Consumption rates
Taking into account the increasing rates of consumption natural resources It is difficult to give an unambiguous assessment of fuel availability for a long period. Given the current dynamics, oil production in 2018 will be 3 billion tons, which will lead to the depletion of world reserves by 80% by 2030. The supply of black gold is projected to be within 55 - 50 years. Natural gas could be exhausted within 60 years at current consumption rates.
There are much more coal reserves on Earth than oil and gas. However, over the last decade its production has increased, and if the pace does not slow down, then out of the planned 420 years (existing forecasts) the reserves will be depleted in 200.
Environmental impact
The active use of fossil fuels leads to an increase in the emission of carbon dioxide (CO2) into the atmosphere, the detrimental effect of which on the planet’s climate has been confirmed by international environmental organizations. If CO2 emissions are not reduced, it is inevitable ecological catastrophy, the beginning of which can be observed by contemporaries. According to preliminary estimates, from 60% to 80% of all fossil fuel reserves must remain untouched to stabilize the situation on Earth. However, this is not the only one by-effect use of fossil fuels. Extraction itself, transportation, and refining at refineries contribute to pollution environment much more toxic substances. An example is the accident in the Gulf of Mexico, which led to the suspension of the Gulf Stream.
Limitations and Alternatives
Mining of fossil fuels - profitable business for companies whose main limitation is the depletion of natural reserves. People usually forget to mention that the voids formed by human activity in the bowels of the earth contribute to the disappearance of fresh water on the surface and its withdrawal into deeper layers. Disappearance drinking water on Earth, no benefits of fossil fuel mining can be justified. And it will happen if humanity does not rationalize its stay on the planet.
Five years ago, motorcycles and cars with new generation engines (fuel-free) appeared in China. But they were released in strictly limited quantities (for a certain circle of people), and the technology became classified. This only speaks of the short-sightedness of human greed, because if you can “make money” on oil and gas, no one will interfere oil tycoons do this.
Conclusion
Along with well-known alternative (renewable) energy sources, there are less expensive, but classified technologies. Nevertheless, their use must inevitably enter into a person’s life, otherwise the future will not be as long and cloudless as “businessmen” imagine it to be.
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 hydrocarbons with low molecular weight. 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 gas is specific to each field. There is the following pattern: the higher the relative molecular weight of the hydrocarbon, the less it is contained in natural gas.
Natural gas is widely used as a cheap fuel with a high calorific value (up to 54,400 kJ is released when 1 m 3 is burned). This is one of best views fuels for domestic and industrial needs. In addition, natural gas serves as 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 oil is extracted 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 vapors, 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 household fuel. Gas gasoline (a mixture of pentane and hexane) is used as an additive to gasoline for better ignition of the fuel when starting the engine. The oxidation of hydrocarbons produces organic acids, alcohols and other products.
Oil– an oily, flammable liquid of dark brown or almost black color with a characteristic odor. It is lighter than water (= 0.73–0.97 g/cm3) and is practically insoluble in water. In terms of composition, oil is a complex mixture of hydrocarbons of different 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). Typically these are alkanes (mostly of normal structure), cycloalkanes and arenes, the ratio of which in oils from different fields varies widely. Ural oil contains more arenes. In addition to hydrocarbons, oil contains oxygen, sulfur and nitrogenous organic compounds.
Crude oil is not usually used. To obtain technically valuable products from oil, it is subjected to processing.
Primary processing oil consists of its distillation. Distillation is carried out at oil refineries after separation of associated gases. When distilling oil, light petroleum products are obtained:
gasoline ( t boil = 40–200 °C) contains hydrocarbons C 5 – C 11,
naphtha ( t boil = 150–250 °C) contains hydrocarbons C 8 – C 14,
kerosene ( t boil = 180–300 °C) contains hydrocarbons C 12 – C 18,
gas oil ( t kip > 275 °C),
and the remainder is a viscous black liquid - fuel oil.
The fuel oil is subjected to further processing. It is distilled under reduced pressure (to prevent decomposition) and lubricating oils are isolated: spindle, machine, cylinder, etc. Vaseline and paraffin are isolated from fuel oil of some types of oil. The remainder of the fuel oil after distillation - tar - after partial oxidation is used to produce asphalt. The main disadvantage of oil distillation is the low yield of gasoline (no more than 20%).
Petroleum distillation products have various uses.
Petrol It is used in large quantities as aviation and automobile fuel. It usually consists of hydrocarbons containing an average of 5 to 9 C atoms in their molecules. Naphtha It is used as fuel for tractors, and also as a solvent in the paint and varnish industry. Large quantities of it are processed into gasoline. Kerosene It is used as fuel for tractors, jet aircraft and rockets, as well as for domestic needs. Solar oil – gas oil– used as motor fuel, and lubricating oils– for lubrication of mechanisms. Petrolatum used in medicine. It consists of a mixture of liquid and solid hydrocarbons. Paraffin used for the production of higher carboxylic acids, for impregnating wood in the production of matches and pencils, for making 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, the structure of the hydrocarbons included in its composition changes. Among these methods great importance has cracking of petroleum hydrocarbons, carried out to increase the yield of gasoline (up to 65–70%).
Cracking– the process of splitting hydrocarbons contained in oil, which results in the formation of hydrocarbons with a smaller number of C atoms in the molecule. 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),
This method is used to produce mainly motor gasoline. Its yield from oil reaches 70%. Thermal cracking was discovered by Russian engineer V.G. Shukhov in 1891.
Catalytic cracking carried out in the presence of catalysts (usually aluminosilicates) at 450–500 °C and atmospheric pressure. This method produces aviation gasoline with a yield of up to 80%. This type of cracking mainly affects kerosene and gas oil fractions of oil. During catalytic cracking, along with splitting 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 cracking gasoline has a higher quality. The process of obtaining it proceeds much faster, with less thermal energy consumption. In addition, catalytic cracking produces relatively many branched-chain hydrocarbons (isocompounds), which are of great value for organic synthesis.
At t= 700 °C and above pyrolysis occurs.
Pyrolysis– decomposition of organic substances without air access during high temperature. In the pyrolysis of oil, 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 (gasoline upgrading).
Reforming- This is the aromatization of gasoline, 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 last years Petroleum hydrocarbons are widely used as a source of chemical raw materials. Different ways from them we obtain substances necessary for the production of plastics, synthetic textile fibers, synthetic rubber, alcohols, acids, synthetic detergents, explosives, pesticides, synthetic fats, etc.
Coal Just like natural gas and oil, it is a source of energy and valuable chemical raw materials.
The main method of processing coal is coking(dry distillation). When coking (heating to 1000 °C - 1200 °C without air access), various products are obtained: coke, coal tar, tar water and coke oven gas (diagram).
Scheme
Coke is used as a reducing agent in the production of cast 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. Pitch is a thick black mass remaining after distillation of the resin, used for the preparation of electrodes and roofing felt.
Ammonia, ammonium sulfate, phenol, etc. are obtained from tar water.
Coke oven gas is used to heat coke ovens (about 18,000 kJ are released when 1 m 3 is burned), but it is mainly subjected to chemical processing. Thus, hydrogen is isolated 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.