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Composition of natural and associated petroleum gases. Presentation "natural and associated petroleum gas"

Natural gas – this is a mixture that consists of: 88-95% methane (CH 4), 3-8% ethane (C 2 H 6), 0.7-2% propane (C 3 H 8), 0.2-0.7 % butane (C 4 H 10), 0.03-0.5% pentane (C 5 H 12), carbon dioxide (CO 2), nitrogen (N 2), helium (He). There is a pattern: The higher the relative molecular weight of a hydrocarbon, the less of it is contained in natural gas. Application:

1) fuel in industry and in everyday life, because CH 4 + 2O 2 = CO 2 + 2H 2 O + 890 KJ

2) obtaining halogenated hydrocarbons and hydrogen chloride:

CH 4 + Cl 2 → CH 3 Cl + HCl, CH 3 Cl - chloromethane - solvent, raw material for organosilicon compounds; HCl – production of hydrochloric acid

3) production of unsaturated hydrocarbons: 2 CH 4 → C 2 H 2 + 3H 2, (C 2 H 2 - acetylene - ethylene - welding and cutting of metals); C 2 H 6 → C 2 H 4 + H 2 (C 2 H 4 – ethylene – ethene - production of polyethylene, ethanol, acetic acid)

4) production of hydrogen and soot: CH 4 → C + 2H 2, (C – soot → rubber and printing inks, H 2 → ammonia NH 3)

5) obtaining oxygen-containing organic compounds:

CH 3 ─ (CH 2) 2 ─ CH 3 → 2CH 3 COOH + H 2 O, CH 3 COOH - acetic acid, production of dyes, medicines….

Associated petroleum gas be located above oil deposits or dissolved in it under pressure.

Contains hydrocarbons, which for rational use are divided into mixtures:

1) gas gasoline(pentane (C 5 H 12) and hexane (C 6 H 14)) are added to gasoline to improve engine performance;

2) propane - butane(propane (C 3 H 8) and butane (C 4 H 10)) in liquefied form as fuel;

3) dry gas(similar in composition to natural) to produce C 2 H 2 - acetylene, H 2 and other substances as fuel: CH 4 + H 2 O ↔ 3H 2 + CO; CO + H 2 ↔ CH 3 OH, CH 3 OH - methanol

About synthesis gas

CH 4 + O 2 → H 2 O + HC, HCHO – methanal, formic aldehyde.

Arenas

Arenas, aromatic hydrocarbons – organic compounds whose molecules contain stable cyclic structures - benzene rings, with a special nature of bonds. General formula:CnH2n-6, where n ≥ 6.

Physical properties:

C6H6- benzene– liquid, colorless, characteristic odor, T bp = 80 ° C, T pl = 5.5 ° C, insoluble in H 2 O, density = 0.879 g/cm³, molar mass = 78.11 g/mol, good solvent , poisonous. Discovered by M. Faraday in illuminating gas in 1825.

Structure

The molecule is flat, the carbon atoms are combined into a regular hexagon, and are in a state sp 2 – hybridization, bond angle = 120°; length (C≡WITH)=0.140 nm.Six unpaired non-hybrid p electrons form a single π -electronic system(aromatic ring), which is located perpendicular to the plane of the benzene ring, overlapping with each other above and below this plane.

Chemical properties

I. Similarity with saturated hydrocarbons.

1. Qualitative reactions. Resistance to conventional oxidizing agents: solutions of bromine water (Br 2 aq) (under normal conditions) and potassium permanganate (KMnO 4) do not discolor.

2. Substitution reactions:

A) Halogenation, interaction with halogens (when heated and in the presence of catalysts): C 6 H 6 + Cl 2 FeCl3 C 6 H 5 Cl + HCl, chlorobenzene

B) Nitration, interaction with concentrated nitric acid (when heated and in the presence of concentrated sulfuric acid):

C 6 H 6 + HNO 3 H 2 SO 4 C 6 H 5 NO 2 + H 2 O, nitrobenzene

B) Alkylation, interaction with halogen derivatives (with heating and in the presence of catalysts) (Friedel-Crafts reaction):

C 6 H 6 + C 2 H 5 Cl AlCl3 C 6 H 5 C 2 H 5 + HCl, ethylbenzene

II. Similarities with unsaturated hydrocarbons. Addition reactions:

1. Hydrogenation, addition of hydrogen (with heating and in the presence of catalysts): C 6 H 6 + 3H 2 t kat C 6 H 12, cyclohexane

2. Halogenation, addition of halogens (in light and in the presence of a catalyst):

C 6 H 6 + 3Cl 2 lighting C 6 H 6 Cl 6 , hexachlorocyclohexane, hexochlorane

3. Unlike unsaturated hydrocarbons, they do not interact with H 2 O, hydrogen halides, or KMnO 4 solution.

Receipt:

1. Isolation from natural sources: oil, coal;

2. Aromatization of oil: 1) dehydrogenation of cycloalkanes: C 6 H 12 t kat C 6 H 6 + 3H 2 ;

2) cyclization and dehydrogenation of alkanes: C 6 H 14 t kat C 6 H 6 + 3H 2;

3) trimerization of alkynes: 2C 2 H 2 t kat C 6 H 6

Application:

1. Solvent; 2. Additive to motor fuel; 3. In organic syntheses: obtaining nitrobenzene, aniline and dyes; chlorobenzene, phenol and phenol-formaldehyde resins, etc.

Biological effect

Short-term inhalation of benzene vapor does not cause immediate poisoning, therefore, until recently, the procedure for working with benzene was not particularly regulated. In large doses, benzene causes nausea and dizziness, and in some severe cases, poisoning can be fatal. Benzene vapor can penetrate intact skin. If the human body is exposed to benzene in small quantities for a long time, the consequences can also be very serious. In this case, chronic benzene poisoning can cause leukemia (blood cancer) and anemia (lack of hemoglobin in the blood). Strong carcinogen.

Oil

Oil - dark, oily liquid with a peculiar odor, lighter than water and insoluble in it (this explains a large number of environmental disasters associated with oil spills during production and transportation at sea and on land).

Oil contains mainly straight and branched alkanes, cycloalkanes (naphthenes) and aromatic hydrocarbons. Their presence and ratio in oil depends on its field. There are also organic compounds that contain oxygen, nitrogen, sulfur and other elements, as well as high-molecular substances (resins and asphalt substances).

Petroleum products. Fractional distillation of “crude” oil leads to the formation of:

1) gasoline contains hydrocarbons C 6 - C 9, boil at temperatures from 40 to 200 ° C, used for internal combustion engines;

2) naphtha contains hydrocarbons C 8 - C 14, boils at temperatures from 150 to 250 ° C, is used as fuel for tractors;

3) kerosene contains hydrocarbons C 9 - C 16, boil at temperatures from 220 to 275 ° C, used as fuel for turbine engines, cracking to lower hydrocarbons;

4) gas oil or diesel fuel boil at temperatures from 200 to 400 ° C, used as fuel for diesel engines;

5) fuel oil contains hydrocarbons C 20 - ..., high boiling, it is divided into fractions: solar oils- diesel fuel, lubricating oils- automotive, aviation, industrial, etc., petrolatum– basis for cosmetics and medicines. Sometimes they get paraffin– for the production of matches, candles, etc. After distillation, it remains tar, which is used in road construction.

For a long time, associated petroleum gas had no value. It was considered a harmful impurity during oil production and was burned directly when gas came out of an oil-bearing well. But time passed. New technologies have emerged that have allowed us to take a different look at APG and its properties.

Compound

Associated petroleum gas is located in the “cap” of the oil-bearing formation - the space between the soil and the deposits fossil oil. Also, some of it is in a dissolved state in the oil itself. Essentially, APG is the same natural gas, the composition of which is big amount impurities.

Associated petroleum gas has a wide variety of contents various kinds hydrocarbons. These are mainly ethane, propane, methane, butane. It also contains heavier hydrocarbons: pentane and hexane. In addition, petroleum gas includes a certain amount of non-flammable components: helium, hydrogen sulfide, carbon dioxide, nitrogen and argon.

It is worth noting that the composition of associated petroleum gas is extremely unstable. The same APG deposit can noticeably change the percentage of certain elements over the course of several years. This is especially true for methane and ethane. But even despite this, oil gas is highly energy-intensive. One cubic meter of APG, depending on the type of hydrocarbons that are included in its composition, is capable of releasing from 9,000 to 15,000 kcal of energy, which makes it promising for use in various economic secateurs.

The leaders in associated petroleum gas production are Iran, Iraq, Saudi Arabia, Russian Federation and other countries in which the main oil reserves are concentrated. Russia accounts for about 50 billion cubic meters of associated petroleum gas per year. Half of this volume goes to needs production areas, 25% for additional processing, and the rest is incinerated.

Cleaning

Associated petroleum gas is not used in its original form. Its use becomes possible only after preliminary cleaning. To do this, layers of hydrocarbons having different densities are separated from each other in equipment specially designed for this purpose - a multi-stage pressure separator.

Everyone knows that water in the mountains boils at a lower temperature. Depending on the altitude, its boiling point can drop to 95 ºС. This happens due to the difference atmospheric pressure. This principle is used in the operation of multi-stage separators.

Initially, the separator supplies a pressure of 30 atmospheres and after a certain period of time gradually reduces its value in steps of 2-4 atmospheres. This ensures uniform separation of hydrocarbons from different temperatures boiling from each other. Next, the resulting components are sent directly to the next stage of purification to oil refining plants.

Application of associated petroleum gas

Now it is actively in demand in some areas of production. First of all, this is the chemical industry. For her, APG serves as a material for the production of plastics and rubber.

The energy industry is also partial to the byproduct of oil production. APG is the raw material from which the following types of fuel are produced:

Dry stripped gas.
Wide fraction of light hydrocarbons.
Gas motor fuel.
Liquefied petroleum gas.
Stable gas gasoline.
Separate fractions based on carbon and hydrogen: ethane, propane, butane and other gases.

The volume of use of associated petroleum gas would be even higher if not for a number of difficulties that arise during its transportation:

The need to remove mechanical impurities from the gas composition. When APG flows out of a well, tiny soil particles enter the gas, which significantly reduce its transport properties.
Associated petroleum gas must undergo a petroleum treatment procedure. Without this, the liquefied fraction will precipitate in the gas pipeline during its transportation.
The composition of associated petroleum gas must be purified from sulfur. Increased sulfur content is one of the main reasons for the formation of corrosion spots in the pipeline.
Removal of nitrogen and carbon dioxide to increase the heating value of the gas.

Due to the above reasons for a long time Associated petroleum gas was not utilized, but burned directly near the well where the oil was located. It was especially good to watch this while flying over Siberia, where torches with black clouds of smoke emanating from them were constantly visible. This continued until environmentalists intervened, realizing all the irreparable harm that was being caused to nature in this way.

Consequences of burning

Gas combustion is accompanied by an active thermal effect on environment. Within a radius of 50-100 meters from the immediate location of the fire, there is a noticeable decrease in the volume of vegetation, and at a distance of up to 10 meters there is a complete absence of vegetation. This is mainly due to burnout nutrients soils on which all kinds of trees and grasses depend so much.

A burning torch serves as a source of carbon monoxide, the same one that is responsible for the destruction of the Earth's ozone layer. In addition, the gas contains sulfur dioxide and nitrogen oxide. These elements belong to the group toxic substances for living organisms.

Thus, people living in areas with active oil production have an increased risk of developing various types of pathologies: oncology, infertility, weakened immunity, etc.

For this reason, at the end of the 2000s, the issue of APG utilization arose, which we will consider below.

Methods for utilization of associated petroleum gas

On this moment There are many options for disposing of oil waste without harming the environment. The most common ones are:

Sent directly to the oil refinery. It is the most optimal solution, both from a financial and environmental point of view. But provided that there is already a developed gas pipeline infrastructure. In its absence, a significant investment of capital will be required, which is justified only in the case of large deposits.
Recycling by using APG as fuel. Associated petroleum gas is supplied to power plants, where, using gas turbines it is produced from it electrical energy. The disadvantage of this method is the need to install equipment for pre-cleaning, as well as its transportation to its destination.
Injection of spent APG into the underlying oil reservoir, thereby increasing the oil recovery factor of the well. This happens due to the increase under the soil layer. This option It is characterized by ease of implementation and relatively low cost of the equipment used. There is only one drawback here - the lack of actual utilization of APG. There is only a delay, but the problem remains unresolved.

Associated petroleum gas.

Associated petroleum gas is also natural gas in origin. It received a special name because it is located in deposits together with oil - it is dissolved in it and is located above the oil, forming a gas “cap”. Associated gas dissolves in oil, since great depth is under pressure. When extracted to the surface, the pressure in the liquid-gas system drops, as a result of which the solubility of the gas decreases and gas is released from the oil. This phenomenon makes oil production a fire and explosion hazard. The composition of natural and associated gases from different fields is different. Associated gases are more diverse in hydrocarbon components than natural gases, so it is more profitable to use them as chemical raw materials.

Associated gas, unlike natural gas contains mainly propane and butane isomers.

Characteristics of associated petroleum gases

Associated petroleum gas is also formed as a result of natural cracking of oil, therefore it includes saturated (methane and homologues) and unsaturated (ethylene and homologues) hydrocarbons, as well as non-flammable gases - nitrogen, argon and carbon dioxide CO 2. Previously, associated gas was not used and was immediately flared at the field. It is now increasingly being captured because, like natural gas, it is a good fuel and a valuable chemical feedstock.

Associated gases are processed at gas processing plants. From them they produce methane, ethane, propane, butane and “light” gas gasoline containing hydrocarbons with the number of carbon atoms 5 or more. Ethane and propane are dehydrogenated to produce unsaturated hydrocarbons - ethylene and propylene. A mixture of propane and butane (liquefied gas) is used as household fuel. Gasoline is added to regular gasoline to speed up its ignition when starting internal combustion engines.

Oil

Oil is a liquid combustible fossil of an oily appearance from yellow or light brown to black with a characteristic odor, with a density of 0.70 - 1.04 g/cm³, lighter than water, insoluble in water, it is a natural complex mixture of predominantly liquid hydrocarbons, in mainly alkanes of linear and branched structure, containing from 5 to 50 carbon atoms in molecules, with others organic substances. Since oil is a mixture of various hydrocarbons, it does not have a specific boiling point. Gaseous and solid components of oil are dissolved in its liquid components, which determines its state of aggregation.

Its composition significantly depends on the place of its extraction. The composition of oils is paraffinic, naphthenic and aromatic. For example, Baku oil is rich in cyclic hydrocarbons (up to 90%), saturated hydrocarbons predominate in Grozny oil, and aromatic hydrocarbons predominate in Ural oil. The most common oils are of mixed composition. Based on density, light and heavy oil are distinguished. However, oil is the most common mixed type. In addition to hydrocarbons, oil contains impurities of organic oxygen and sulfur compounds, as well as water and calcium and magnesium salts dissolved in it. In total, oil contains about 100 different compounds. Oil also contains mechanical impurities – sand and clay.

D.I. Mendeleev believed that oil is a valuable raw material for the production of many organic products.

Oil is a valuable raw material for producing high-quality motor fuels. After purification from water and other unwanted impurities, the oil is processed.

Most of the oil is used for production (90%) is used for production various types fuels and lubricants. Oil is a valuable raw material for chemical industry. Although the portion of oil that is used to produce petrochemical products is small, these products have very great importance. Many thousands of organic compounds are obtained from petroleum distillation products. They, in turn, are used to produce thousands of products that satisfy not only basic needs modern society, but also the need for comfort. From substances extracted from oil we obtain:

Synthetic rubbers;

Plastics;

Explosives;

Medications;

Synthetic fibers;

Natural gases are gases in a free state or in a bound form of the atmosphere, surface or interior of the Earth, and even gases found in the waters of the world's oceans. Natural gases are often the result of geological or biological activity; these are gases of the “current moment”, that is, produced and released at the current moment in time (volcanic - during a volcanic eruption, biochemical - during the activity of saprophyte bacteria decomposing protein remains, etc.)

Associated petroleum gas is also a kind of natural gas, but it is dissolved in oil or located in the “cap” oil fields. That is, it is once formed gas that remains in a stable state until oil production. As a rule, it is not released into the environment by itself, does not undergo changes and does not interact with the inhabitants of biocenoses.

Differences in composition:

natural gas is methane and ethane (mainly), associated petroleum gas contains significantly less methane and ethane, a significant proportion of propanes, butanes, heavy hydrocarbon vapors, non-hydrocarbon components (helium, nitrogen, argon, hydrogen sulfide, marcaptans, etc.)

Another major difference is the harmfulness factor. Natural gas is, in principle, safe for the environment; in addition, it is actively used in everyday life (all of our kitchen stoves run on this fuel). But once in a while you’ll be tormented by recycling (at least in our country, with the mentality “it’s easier to throw it away than to put it in good hands"), because most of it is simply burned in flares and colossal harm is caused to nature.

6. 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.

Related petroleum gases divided into the following fractions:

1) Dry gas - similar in composition to natural gas.

2) Propane-butane fraction - a mixture of propane and butane.

3) Gas gasoline is a mixture of pentane and hexane isomers.

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 by oil refining, are divided into motor and boiler. TO gaseous fuel include hydrocarbon liquefied fuel gases used for public utilities. 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 (C 16 and higher) - paraffins, ceresins, used in the perfume industry and in the form of 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.

Associated petroleum gas

Associated petroleum gas (PNG) - a mixture of various gaseous hydrocarbons dissolved in oil; they are released during the extraction and distillation process (these are the so-called associated gases, mainly composed of propane and butane isomers). Petroleum gases also include petroleum cracking gases, consisting of saturated and unsaturated (ethylene, acetylene) hydrocarbons. Petroleum gases are used as fuel and to produce various chemical substances. From petroleum gases, propylene, butylenes, butadiene, etc. are obtained through chemical processing, which are used in the production of plastics and rubbers.

Compound

Associated petroleum gas is a mixture of gases released from hydrocarbons of any phase state, consisting of methane, ethane, propane, butane and isobutane, containing high molecular weight liquids dissolved in it (from pentanes and higher in the homologous series) and impurities of various compositions and phase states.

Approximate composition of APG

Receipt

APG is a valuable hydrocarbon component released from mined, transported and processed hydrocarbon-containing minerals at all stages of the investment life cycle before the sale of finished products to the final consumer. Thus, the peculiarity of the origin of oil associated gas is that it is released at any stage from exploration and production to final sale, from oil, gas, (other sources omitted) and during their processing from any incomplete product state to any of the numerous final products.

A specific feature of APG is usually the low consumption of the resulting gas, from 100 to 5000 Nm³/hour. The content of hydrocarbons C3 + can vary in the range from 100 to 600 g/m³. At the same time, the composition and quantity of APG is not a constant value. Both seasonal and one-time fluctuations are possible (normal changes in values are up to 15%).

The gas from the first separation stage is usually sent directly to the gas processing plant. Significant difficulties arise when trying to use gas with a pressure of less than 5 bar. Until recently, such gas in the vast majority of cases was simply flared, however, now, due to changes in state policy in the field of APG utilization and a number of other factors, the situation is changing significantly. In accordance with the Decree of the Government of Russia of January 8, 2009 No. 7 “On measures to stimulate the reduction of pollution atmospheric air products of combustion of associated petroleum gas in flares”, a target indicator for flaring of associated petroleum gas was established in the amount of no more than 5 percent of the volume of produced associated petroleum gas. At the moment, the volumes of extracted, utilized and flared APG cannot be estimated due to the lack of gas metering stations at many fields. But according to rough estimates, this is about 25 billion m³.

Disposal routes

The main ways of APG utilization are processing at gas processing plants, generating electricity, burning for own needs, injection back into the reservoir to enhance oil recovery (maintaining reservoir pressure), injection into production wells - the use of “gas lift”.

APG utilization technology

Gas flare in the West Siberian taiga in the early 1980s

The main problem in the utilization of associated gas is the high content of heavy hydrocarbons. Today, there are several technologies that improve the quality of APG by removing a significant portion of heavy hydrocarbons. One of them is the preparation of APG using membrane units. When using membranes, the methane number of gas increases significantly, the lowest calorific value(LHV), heat equivalent and dew point temperature (both hydrocarbon and water) are reduced.

Membrane hydrocarbon units can significantly reduce the concentration of hydrogen sulfide and carbon dioxide in the gas flow, which allows them to be used to purify gas from acidic components.

Design

Gas flow distribution diagram in the membrane module

By its design, the hydrocarbon membrane is a cylindrical block with permeate, product gas outlets and an APG inlet. Inside the block there is a tubular structure of selective material that allows only certain type molecules. General scheme flow inside the cartridge is shown in the figure.

Principle of operation

The installation configuration in each specific case is determined specifically, since the initial composition of APG can vary greatly.

Installation diagram in basic configuration:

Pressure scheme for APG preparation

Vacuum scheme for APG preparation

Pre-separator for cleaning from coarse impurities, large droplets of moisture and oil,
Receiver at the input,
Compressor,
Refrigerator for additional cooling of gas to a temperature of +10 to +20 °C,