It should be noted that hydrocarbons are widely distributed in nature. Majority organic matter obtained from natural sources. In the process of synthesis of organic compounds, natural and associated gases, coal and brown coal, oil, peat, products of animal and vegetable origin are used as raw materials.
Natural sources of hydrocarbons: natural gases.
Natural gases are natural mixtures of hydrocarbons of various structures and some gas impurities (hydrogen sulfide, hydrogen, carbon dioxide) that fill the rocks in the earth's crust. These compounds are formed as a result of hydrolysis of organic substances at great depths in the Earth's thickness. They are found in a free state in the form of huge accumulations - gas, gas condensate and oil and gas fields.
The main structural component of combustible natural gases is CH₄ (methane - 98%), С₂Н₆ (ethane - 4.5%), propane (С₃Н₈ - 1.7%), butane (С₄Н₁₀ - 0.8%), pentane (С₅Н₁₂ - 0 .6%). Associated petroleum gas is part of the oil in a dissolved state and is released from it due to a decrease in pressure when the oil rises to the surface. In gas and oil fields, one ton of oil contains from 30 to 300 sq. m of gas. Natural sources of hydrocarbons are a valuable fuel and raw material for the organic synthesis industry. Gas is supplied to gas processing enterprises, where it can be processed (oil, low-temperature adsorption, condensation and rectification). It is divided into separate components, each of which is used for specific purposes. For example, from methane synthesis gas, which are the basic raw materials for the production of other hydrocarbons, acetylene, methanol, methanal, chloroform.
Natural sources of hydrocarbons: oil.
Oil is a complex mixture that consists mainly of naphthenic, paraffinic and aromatic hydrocarbons. The composition of oil includes asphalt-resinous substances, mono- and disulfides, mercaptans, thiophene, thiophane, hydrogen sulfide, piperidine, pyridine and its homologues, as well as other substances. Based on the products, more than 3,000 different products are obtained using petrochemical synthesis methods, incl. ethylene, benzene, propylene, dichloroethane, vinyl chloride, styrene, ethanol, isopropanol, butylenes, various plastics, chemical fibers, dyes, detergents, drugs, explosives, etc.
Peat is a sedimentary rock of plant origin. This substance is used as a fuel (mainly for thermal power plants), as a chemical raw material (for the synthesis of many organic substances), as an antiseptic bedding on farms, especially in poultry farms, as a component of fertilizers for gardening and field crops.
Natural sources of hydrocarbons: xylem or wood.
Xylem is a tissue of higher plants, through which water and dissolved nutrients come from the rhizome of the system to the leaves, as well as other plant organs. It consists of cells with a stiff shell, which have a vascular conduction system. Depending on the type of wood, it contains different amounts of pectin and mineral compounds (mainly calcium salts), lipids and essential oils. Wood is used as a fuel; methyl alcohol, acetic acid, cellulose, and other substances can be synthesized from it. From some types of wood, dyes are obtained (sandalwood, logwood), tannins (oak), resins and balsams (cedar, pine, spruce), alkaloids (plants of the nightshade, poppy, ranunculus, umbrella families). Some alkaloids are used as medicines (chitin, caffeine), herbicides (anabasine), insecticides (nicotine).
The most important sources of hydrocarbons are natural and associated petroleum gases, oil, and coal.
By reserves natural gas the first place in the world belongs to our country. Natural gas contains low molecular weight hydrocarbons. It has the following approximate composition (by volume): 80-98% methane, 2-3% of its closest homologues - ethane, propane, butane and a small amount of impurities - hydrogen sulfide H 2 S, nitrogen N 2 , noble gases, carbon monoxide (IV ) CO 2 and water vapor H 2 O . The composition of the gas is specific to each field. There is the following pattern: the higher the relative molecular weight of hydrocarbon, the less it is contained in natural gas.
Natural gas is widely used as a cheap fuel with high calorific value (combustion of 1m 3 releases up to 54,400 kJ). This is one of the best views fuel for domestic and industrial needs. In addition, natural gas is a valuable raw material for the chemical industry: the production of acetylene, ethylene, hydrogen, soot, various plastics, acetic acid, dyes, medicines and other products.
Associated petroleum gases are in deposits together with oil: they are dissolved in it and are located above the oil, forming a gas “cap”. When extracting oil to the surface, gases are separated from it due to a sharp drop in pressure. Previously, associated gases were not used and were flared during oil production. Currently, they are captured and used as fuel and valuable chemical raw materials. Associated gases contain less methane than natural gas, but more ethane, propane, butane and higher hydrocarbons. In addition, they contain basically the same impurities as in natural gas: H 2 S, N 2, noble gases, H 2 O vapor, CO 2 . Individual hydrocarbons (ethane, propane, butane, etc.) are extracted from associated gases, their processing makes it possible to obtain unsaturated hydrocarbons by dehydrogenation - propylene, butylene, butadiene, from which rubbers and plastics are then synthesized. A mixture of propane and butane (liquefied gas) is used as a household fuel. Natural gasoline (a mixture of pentane and hexane) is used as an additive to gasoline for better ignition of the fuel when starting the engine. Oxidation of hydrocarbons produces organic acids, alcohols and other products.
Oil- oily flammable liquid of dark brown or almost black color with a characteristic odor. It is lighter than water (= 0.73–0.97 g / cm 3), practically insoluble in water. By composition, oil is a complex mixture of hydrocarbons of various molecular weights, so it does not have a specific boiling point.
Oil consists mainly of liquid hydrocarbons (solid and gaseous hydrocarbons are dissolved in them). Usually these are alkanes (mainly of a normal structure), cycloalkanes and arenes, the ratio of which in oils from various fields varies widely. Ural oil contains more arenes. In addition to hydrocarbons, oil contains oxygen, sulfur and nitrogenous organic compounds.
Crude oil is not normally used. To obtain technically valuable products from oil, it is subjected to processing.
Primary processing oil consists in its distillation. Distillation is carried out at refineries after the separation of associated gases. During the distillation of oil, light oil products are obtained:
gasoline ( t kip \u003d 40–200 ° С) contains hydrocarbons С 5 -С 11,
naphtha ( t kip \u003d 150–250 ° С) contains hydrocarbons С 8 -С 14,
kerosene ( t kip \u003d 180–300 ° С) contains hydrocarbons С 12 -С 18,
gas oil ( t kip > 275 °C),
and in the remainder - a viscous black liquid - fuel oil.
Oil is subjected to further processing. It is distilled under reduced pressure (to prevent decomposition) and lubricating oils are isolated: spindle, engine, cylinder, etc. Petroleum jelly and paraffin are isolated from fuel oil of some grades of oil. The residue of fuel oil after distillation - tar - after partial oxidation is used to produce asphalt. Main disadvantage oil distillation - a small yield of gasoline (no more than 20%).
Oil distillation products have various uses.
Petrol used in large quantities as aviation and automotive fuel. It usually consists of hydrocarbons containing an average of 5 to 9 C atoms in molecules. Naphtha It is used as a fuel for tractors, as well as a solvent in the paint and varnish industry. Large quantities are processed into gasoline. Kerosene It is used as a fuel for tractors, jet planes and rockets, as well as for domestic needs. solar oil - gas oil- used as a motor fuel, and lubricating oils- for lubricating mechanisms. Petrolatum used in medicine. It consists of a mixture of liquid and solid hydrocarbons. Paraffin used to obtain higher carboxylic acids, to impregnate wood in the production of matches and pencils, for the manufacture of candles, shoe polish, etc. It consists of a mixture of solid hydrocarbons. fuel oil in addition to processing into lubricating oils and gasoline, it is used as boiler liquid fuel.
At secondary processing methods oil is a change in the structure of the hydrocarbons that make up its composition. Among these methods, of great importance is the cracking of oil hydrocarbons, which is carried out in order to increase the yield of gasoline (up to 65–70%).
Cracking- the process of splitting hydrocarbons contained in oil, as a result of which hydrocarbons with a smaller number of C atoms in the molecule are formed. There are two main types of cracking: thermal and catalytic.
Thermal cracking is carried out by heating the feedstock (fuel oil, etc.) at a temperature of 470–550 °C and a pressure of 2–6 MPa. At the same time, hydrocarbon molecules with a large number C atoms are split into molecules with a smaller number of atoms of both saturated and unsaturated hydrocarbons. For example:
(radical mechanism),
In this way, mainly automobile gasoline is obtained. Its output from oil reaches 70%. Thermal cracking was discovered by Russian engineer V.G. Shukhov in 1891.
catalytic cracking carried out in the presence of catalysts (usually aluminosilicates) at 450–500 °C and atmospheric pressure. In this way, aviation gasoline is obtained with a yield of up to 80%. This type of cracking is mainly subjected to kerosene and gas oil fractions of oil. In catalytic cracking, along with cleavage reactions, isomerization reactions occur. As a result of the latter, saturated hydrocarbons with a branched carbon skeleton of molecules are formed, which improves the quality of gasoline:
Catalytic cracked gasoline is of higher quality. The process of obtaining it proceeds much faster, with less consumption of thermal energy. In addition, during catalytic cracking, relatively many branched-chain hydrocarbons (isocompounds) are formed, which are great value for organic synthesis.
At t= 700 °C and above, pyrolysis occurs.
Pyrolysis- decomposition of organic substances without air access at high temperature. During oil pyrolysis, the main reaction products are unsaturated gaseous hydrocarbons (ethylene, acetylene) and aromatic hydrocarbons - benzene, toluene, etc. Since oil pyrolysis is one of the most important ways to obtain aromatic hydrocarbons, this process is often called oil aromatization.
Aromatization– transformation of alkanes and cycloalkanes into arenes. When heavy fractions of petroleum products are heated in the presence of a catalyst (Pt or Mo), hydrocarbons containing 6–8 C atoms per molecule are converted into aromatic hydrocarbons. These processes occur during reforming (upgrading of gasoline).
Reforming- this is the aromatization of gasolines, carried out as a result of heating them in the presence of a catalyst, for example, Pt. Under these conditions, alkanes and cycloalkanes are converted into aromatic hydrocarbons, as a result of which the octane number of gasoline also increases significantly. Aromatization is used to obtain individual aromatic hydrocarbons (benzene, toluene) from gasoline fractions of oil.
AT last years petroleum hydrocarbons are widely used as a source of chemical raw materials. In various ways, they are used to 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 a valuable chemical raw material.
Main processing method hard coal – coking(dry distillation). During coking (heating up to 1000 °С - 1200 °С without air access), various products are obtained: coke, coal tar, tar water and coke oven gas (scheme).
Scheme
Coke is used as a reducing agent in the production of iron in metallurgical plants.
Coal tar serves as a source of aromatic hydrocarbons. It is subjected to rectification distillation and benzene, toluene, xylene, naphthalene, as well as phenols, nitrogen-containing compounds, etc. are obtained.
Ammonia, ammonium sulfate, phenol, etc. are obtained from tar water.
Coke oven gas is used to heat coke ovens (combustion of 1 m 3 releases about 18,000 kJ), but it is mainly subjected to chemical processing. So, hydrogen is extracted from it for the synthesis of ammonia, which is then used to produce nitrogen fertilizers, as well as methane, benzene, toluene, ammonium sulfate, and ethylene.
Natural sources of hydrocarbons are fossil fuels - oil and
gas, coal and peat. Crude oil and gas deposits arose 100-200 million years ago
back from microscopic marine plants and animals that turned out to be
included in the sedimentary rocks formed at the bottom of the sea, Unlike
that coal and peat began to form 340 million years ago from plants,
growing on dry land.
Natural gas and crude oil are usually found along with water in
oil-bearing layers located between layers of rocks (Fig. 2). Term
"natural gas" also applies to gases that are formed in natural
conditions as a result of the decomposition of coal. Natural gas and crude oil
developed on all continents except Antarctica. the largest
natural gas producers in the world are Russia, Algeria, Iran and
United States. The largest producers of crude oil are
Venezuela, Saudi Arabia, Kuwait and Iran.
Natural gas consists mainly of methane (Table 1).
Crude oil is an oily liquid, the color of which can
be the most diverse - from dark brown or green to almost
colorless. It contains a large number of alkanes. Among them are
straight chain alkanes, branched alkanes and cycloalkanes with the number of atoms
carbon five to 40. The industrial name for these cycloalkanes is numbered. AT
crude oil, in addition, contains approximately 10% aromatic
hydrocarbons, as well as a small amount of other compounds containing
sulfur, oxygen and nitrogen.
Table 1 Composition of natural gas
Coal is the oldest source of energy known to
humanity. It is a mineral (Fig. 3), which was formed from
plant matter during metamorphism. Metamorphic
called rocks, the composition of which has undergone changes in conditions
high pressures as well as high temperatures. The product of the first stage in
process of formation of coal is peat, which is
decomposed organic matter. Coal is formed from peat after
it is covered with sedimentary rocks. These sedimentary rocks are called
overloaded. Overloaded precipitation reduces the moisture content of peat.
Three criteria are used in the classification of coals: purity (determined by
relative carbon content in percent); type (defined
the composition of the original plant matter); grade (depending on
degree of metamorphism).
Table 2 Carbon content in some types of fuel and their calorific value
ability
The lowest grade fossil coals are lignite and
lignite (Table 2). They are closest to peat and are characterized by relatively
characterized by a lower moisture content and is widely used in
industry. The driest and hardest grade of coal is anthracite. His
used for home heating and cooking.
In recent years, thanks to technological advances, it is becoming more and more
economical gasification of coal. Coal gasification products include
carbon monoxide, carbon dioxide, hydrogen, methane and nitrogen. They are used in
as a gaseous fuel or as a raw material for the production of various
chemicals and fertilizers.
Coal, as discussed below, is an important source of raw materials for
aromatic compounds. Coal Represents
a complex mixture of chemicals, which include carbon,
hydrogen and oxygen, as well as small amounts of nitrogen, sulfur and other impurities
elements. In addition, the composition of coal, depending on its grade, includes
varying amounts of moisture and various minerals.
Hydrocarbons occur naturally not only in fossil fuels, but also in
in some materials of biological origin. natural rubber
is an example of a natural hydrocarbon polymer. rubber molecule
consists of thousands of structural units, which are methylbuta-1,3-diene
(isoprene);
natural rubber. Approximately 90% natural rubber, which
currently mined all over the world, obtained from the Brazilian
rubber tree Hevea brasiliensis, cultivated mainly in
equatorial countries of Asia. The sap of this tree, which is latex
(a colloidal aqueous solution of polymer), collected from incisions made with a knife on
bark. Latex contains approximately 30% rubber. Its tiny pieces
suspended in water. The juice is poured into aluminum containers, where acid is added,
causing the rubber to coagulate.
Many other natural compounds also contain isoprene structural
fragments. For example, limonene contains two isoprene moieties. Limonene
is the main integral part oils extracted from the peel of citrus fruits,
such as lemons and oranges. This connection belongs to the class of connections,
called terpenes. Terpenes contain 10 carbon atoms in their molecules (C
10-compounds) and include two isoprene fragments connected to each other
the other sequentially (“head to tail”). Compounds with four isoprene
fragments (C 20 compounds) are called diterpenes, and with six
isoprene fragments - triterpenes (C 30 compounds). Squalene
found in shark liver oil is a triterpene.
Tetraterpenes (C 40 compounds) contain eight isoprene
fragments. Tetraterpenes are found in the pigments of vegetable and animal fats.
origin. Their coloration is due to the presence of a long conjugated system
double bonds. For example, β-carotene is responsible for the characteristic orange
coloring of carrots.
Oil and coal processing technology
AT late XIX in. under the influence of progress in the field of thermal power engineering, transport, engineering, military and a number of other industries, demand has increased immeasurably and an urgent need has arisen for new types of fuel and chemical products.
At this time, the oil refining industry was born and rapidly progressed. A huge impetus to the development of the oil refining industry was given by the invention and rapid spread of the internal combustion engine running on petroleum products. The technique of processing coal, which is not only one of the main types of fuel, but, which is especially noteworthy, became an essential raw material for the chemical industry during the period under review, also developed intensively. A large role in this matter belonged to coke chemistry. Coke plants, which previously supplied coke to the ferrous metallurgy, turned into coke-chemical enterprises, which, in addition, produced a number of valuable chemical products: coke oven gas, crude benzene, coal tar and ammonia.
The production of synthetic organic substances and materials began to develop on the basis of oil and coal processing products. They are widely used as raw materials and semi-finished products in various branches of the chemical industry.
Ticket number 10
State budgetary educational institution
secondary school No. 225 of the Admiralteisky district of St. Petersburg
ESSAY
IN CHEMISTRY
Hydrocarbons and their natural sources
Chemistry teacher:Voronaev Ivan Gennadievich
Grade
St. Petersburg
2018
Introduction
Hydrocarbons are organic compounds consisting of C (carbon) and H (hydrogen) atoms - gaseous, liquid and solid, depending on the molecular weight and on the chemical structure.
The purpose of the abstract is to consider organic compounds, what groups they are divided into, where they occur and the possibility of using hydrocarbons.
Relevance of the topic: It is organic chemistry that is one of the most rapidly developing chemical disciplines that comprehensively affect human life. It is known that the number of organic compounds is too large and, according to some data, reaches about 18 million.
Hydrocarbon classification
A large group of hydrocarbons is divided into aliphatic and aromatic. Aliphatic, in turn, are divided into two subgroups: - saturated or limiting; - unsaturated or unsaturated. In saturated hydrocarbons, all carbon valences are used for connection with neighboring carbon atoms and connection with hydrogen atoms. Unsaturated hydrocarbons are called hydrocarbons, in the molecules of which there are carbon atoms linked by double or triple bonds. The classification of hydrocarbons is systematized in table 1.
Table 1
general characteristics hydrocarbons
Alkanes - these are acyclic hydrocarbons of a linear or branched structure, in the molecules of which carbon atoms are interconnected by simple -connections. Alkanes form a homologous series with the general formula C n H 2n+2 , where n is the number of carbon atoms.
Picture 1. Structural formula of methane
Alkenes - acyclic unsaturated hydrocarbons of a linear or branched structure, in the molecule of which there is one double bond between atomscarbon. General formulaC n H 2n .
Figure 2. Structural formula of ethylene
Alkynes - unsaturated acyclic hydrocarbons containing one C≡C triple bond. Homologous series of acetylene. General formulaC n H 2n–2 . Possible isomerism of the carbon skeleton, isomerism of the position of the triple bond, interclass and spatial. The most characteristic reactions are addition, combustion.
Figure 3 Structural formula of acetylene
Alkadienes - unsaturated acyclic hydrocarbons containing two C=C double bonds. Homologous series of diene hydrocarbons. General formulaC n H 2n–2 . Carbon skeleton isomerism, double bond position isomerism, interclass, cis-trans isomerism are possible. The most typical reactions are addition.
Figure 4 Structural formula of butadiene-1,3
Cycloalkanes - saturated carbocyclic hydrocarbons with single C–C bonds. Homologous series of polymethylenes. General formulaC n H 2n. Possible isomerism of the carbon skeleton, spatial, interclass. For cycloalkanes with n = 3–4, addition reactions with ring opening are most characteristic.
Figure 5 Structural formula of cyclopropane
The formation of hydrocarbons. Application area
The main theory of the origin of hydrocarbons is the decay of plant organisms and animal remains.
Hydrocarbons are used as fuel and as starting products for the synthesis of various substances. The main sources of hydrocarbon production are natural gas and oil.
Natural gas contains mainly low molecular weight hydrocarbons from methane CH 4 to butane C 4 H 10 . Oil contains a variety of hydrocarbons that are higher in molecular weight than natural gas hydrocarbons, such asliquid alkanesWith 5 H 12 - WITH 16 H 34 , make up the bulk of the liquid fractions of oil and solid alkanes of the compositionWith 17 H 36 - WITH 53 H 108 and more, which are included in heavy oil fractions and solid paraffins.
Hydrocarbons, especially cyclic hydrocarbons, are also obtained by dry distillation of coal and oil shale.
A wide variety of products that contain hydrocarbons, and the conditions under which they can be formed again and again, so hydrocarbons can play the role of occupational hazards in almost all industries:
in the extraction of natural liquid and gaseous fuels (gas, oil industry);
in the processing of oil and products derived from it (oil refining and petrochemical industry);
when using products of thermal processing of hard and brown coal, shale, peat, oil for a variety of purposes (as fuel for aircraft, cars, tractors);
as solvents in many industries, as mineral oils.
Hydrocarbons can act as household poisons:
when smoking tobacco (polyaromatic, such as naphthalene C 10 H 8 pyrene C 16 H 10);
as solvents in everyday life (for example, when cleaning clothes);
in case of accidental poisoning, mainly of children, with liquid mixtures of hydrocarbons (gasoline, kerosene).
Hydrocarbons containing up to 5 carbon atoms per molecule (CH 4, C 2 H 2, C 3 H 8, C 4 H 10, C 5 H 12 ) and representing at ordinary temperature and pressure gaseous substances, can be contained in the air in any concentration and lead in some cases to a lack of oxygen in the air (for example, the accumulation of CH4 in coal mines) and to explosions.
Limit hydrocarbons containing from 6 to 9 carbon atoms in a molecule (C 6 H 14, C 7 H 16, C8H 18 octane, C 9 H 20 ), - liquid substances that make up gasoline, kerosene. They are widely used as solvents and thinners for adhesives, varnishes, paints, as well as degreasing agents and can create high vapor concentrations in industrial premises (rubber, paintwork, machine building and other industries).
Heavy hydrocarbons with 10 or more carbon atoms per molecule (petroleum and mineral oils, paraffins, naphthalene, phenanthrene, anthracene, bitumen) are characterized by low volatility, but cause certain lesions with chronic exposure to the skin and mucous membranes, have a general toxic effect. When working with cooling lubricating fluids, for example, fresol and emulsols and emulsions made on their basis (metal cutting), oil folliculitis may develop ( inflammatory process purulent character).
Conclusion
The main classes of hydrocarbons are considered. Finding in nature and scope.
Hydrocarbons have found wide application in industry. Main scope:
as a fuel;
For the synthesis of plastics, rubber, rubber, synthetic fibers, paints, fertilizers, dyes;
For the production of pharmaceutical, hygienic, cosmetics;
For the production of detergents;
For the production of food additives and food products.
Bibliography
Paffengolts K.N. Geological dictionary. - M .: Nedra, 1978. V.2.– 456 p.
Terney A. Modern organic chemistry. - M.: Mir, 1981. V.1-2. - 678 p., 651 p.
Network electronic textbook on organic chemistry, http://cnit.ssau.ru/organics/chem2/
slide 1
slide 2
slide 3
Natural combustible gases - mixtures of gaseous hydrocarbons of various structures, filling the pores and voids of rocks, dispersed in soils, dissolved in formation waters. Associated petroleum gases are mixtures of hydrocarbons that are dissolved in oil or above it in the form of a gas cap. They are released due to a decrease in pressure when oil rises to the surface of the Earth.
slide 4
- West Siberian base (92% of the country's total gas): Urengoy, Yamburg, Medvezhye; - Orenburg - Astrakhan base (6%); - Timano - Pechora base (1%). Urengoy field
slide 5
Gas Natural Associated petroleum Composition Methane 80-97% Ethane, propane, butane, pentane. Nitrogen and other gases. Methane (less than in natural) Ethane, propane, butane, pentane (the greater the mass, the greater the amount of hydrocarbon. Application 90% as a fuel 10% as a chemical raw material for the production of hydrogen, acetylene, soot, ethylene. 90% as a valuable chemical raw materials for the production of hydrogen, acetylene, ethane, propane, etc., Fuel for household and car use, Additive to gasoline.
slide 6
Slide 7
Oil is a dark brown or black viscous liquid. Oil contains alkanes, cycloalkanes and arenes. The composition depends on the deposit. In addition to hydrocarbons, oil contains organic compounds containing oxygen, sulfur, nitrogen, and resins. In total, oil contains about 100 different compounds.
Slide 8
- West Siberian base (70% of the country's total oil): Samotlor, Megion; - Volga-Ural base (25% of all oil): Romashkinskoye, Tuymazy. - Perspective - the shelf of the Barents Sea, Sakhalin (Sea of Okhotsk).
Slide 9
Baku-Supsa oil pipeline Onshore drilling rig Floating drilling rig Offshore oil rig
slide 10
Rectification Naphtha Gasoline Kerosene Gas oil Fuel oil Automotive fuel Factory fuel, lubricating oils Diesel and boiler fuel Jet and rocket fuel Tractor fuel
slide 11
Knock resistance is the ability of a fuel to withstand high compression in an engine (without premature combustion). Octane number is a quantitative indicator of the knock resistance of gasolines. CH3-CH2-CH2-CH2-CH2-CH2-CH3 n-heptane octane number = 0 CH3 2,2,4 - trimethylpentane CH3-C - CH2-CH-CH3 (isooctane) CH3 CH3 octane number = 100
slide 12
Cracking is a chemical process of breaking down petroleum hydrocarbons into more volatile substances in order to increase the yield of gasoline. Reforming is a process of processing gasoline fractions under hydrogen pressure at T = 5000C, in the presence of a platinum catalyst, in order to obtain aromatic and branched saturated hydrocarbons. Pyrolysis is the process of splitting hydrocarbons with strong heating (up to 700 - 9000C).
slide 13
Types of cracking Thermal Catalytic Conditions t = 470-550°С t = 500°С (Al2O3 nSiO2) Products Gasoline containing unsaturated hydrocarbons Gasoline containing unsaturated and branched hydrocarbons Chemistry (CH2)6 -CH2 ||CH2-(CH2) 6 | | CH3 CH3 ≈ 500 °С C8H18 +C8H10 See thermal cracking Cat isomerization, t CH3 -CH2 -CH2 -CH2 –CH3 CH3 -CH -CH2 –CH3 | CH3
slide 14
Coal is a complex mixture of macromolecular compounds, which include: carbon, hydrogen, oxygen, sulfur and nitrogen. Coal coking - heating up to 10000С without air access.
slide 15
1. Kuznetsk basin (Kuzbass) - 40% of production. 2. Kansko - Achinsk brown coal. 3. Pechora basin.
slide 16
Back to Contents Coke oven gas: hydrogen, methane, carbon dioxide, nitrogen, ethylene, etc. Fuel Chemical raw materials Coking products and their use Ammonia water: ammonia, phenol, hydrogen sulfide, etc. Nitrogen fertilizers. Coke At metallurgical plants for blast furnaces. Coal tar: benzene and its homologues, phenol, naphthalene, etc. Chemical raw materials
slide 17
Currently, oil ranks 6th in air pollution and 2nd in water pollution. When fuel is burned, more than 200 million tons of oxides of sulfur, carbon, and nitrogen enter the atmosphere annually. When coal is burned, non-combustible impurities turn into slag, which falls into environment. Up to 60% of all harmful emissions come from cars.
slide 18
- D.I. Mendeleev wrote: "There is no waste in chemistry, but there is inexhaustible raw material." It is necessary to introduce non-waste technologies into production, the integrated use of raw materials; - at the enterprises of the chemical industry, it is necessary to install treatment facilities, use filter materials and dust collectors;
