Today, many different gases are known. Some of them a person receives by laboratory methods, from chemical substances, some form themselves as a result of reactions as by-products. And what gases are born in nature? To the main such gases of natural, natural origin four include:
- natural gas, whose formula is CH 4;
- nitrogen, N 2 ;
- hydrogen, H 2 ;
- carbon dioxide, CO2.
Of course, there are some others - oxygen, hydrogen sulfide, ammonia, carbon monoxide. However, the ones listed above are practically significant for people and are used by them for various purposes, including as fuel.
What is natural gas?
Natural gas is the gas that nature gives us. That is, the content of which in the bowels of the Earth is much higher and greater than the amount that is obtained in industry as a result of chemical reactions.
It is common to call natural gas methane, but this is not entirely true. If we consider the composition of such a gas by fractions, then we can see the following component composition:
- methane (up to 96%);
- ethane;
- propane;
- butane;
- hydrogen;
- carbon dioxide;
- nitrogen;
- hydrogen sulfide (small, trace amounts).
Thus, it turns out that natural gas is a mixture of several
Natural gas formula
From a chemical point of view, natural gas is a mixture of linear hydrocarbons of a simple structure - methane, ethane, propane and butane. But since methane still makes up a larger volume, it is customary to express the general formula of natural gas by the formula of methane itself. So, it turns out that the chemical formula of natural gas is methane -CH 4.
The remaining components have the following empirical formulas in chemistry:
- ethane - C 2 H 6;
- propane - C 3 H 8;
- butane - C 4 H 10;
- carbon dioxide - CO 2;
- nitrogen - N 2;
- hydrogen - H 2;
- hydrogen sulfide - H 2 S.
A mixture of these substances is natural gas. The formula of its main compound, methane, shows that the carbon content in it is very small. This affects its physical properties, such as the ability to burn with a colorless, completely non-smoky flame. While other representatives of its saturated hydrocarbons or alkanes) form a black smoky flame when burned.
Being in nature
In nature, this gas is found deep underground, under thick and dense layers. sedimentary rocks. There are two main theories about the origin of natural gas in nature.
- Theory of tectonic rock movements. Supporters of this theory believe that hydrocarbons are always contained in the bowels of the earth and rise as a result of tectonic movements and upward contractions. At the top, high pressure and changing temperatures turn them through chemical reactions into two natural minerals - oil and gas.
- The biogenic theory speaks of a different method by which natural gas was formed. The formula reflects qualitative composition- carbon and hydrogen, which indicates that living organic beings took part in its formation, whose bodies were for the most part built from these elements, like all life on our planet that still exists. Over time, the dead remains of animals and plants sank lower and lower to the bottom of the ocean, where there was neither oxygen nor bacteria capable of decomposing and processing this organic mass. As a result of anaerobic oxidation, biomass decayed, and over millions of years two sources of minerals were formed - oil and gas. At the same time, the basis of both is the same - and partially low molecular weight substances. The chemical formula of gas and oil proves this. However, when exposed different conditions different products are also formed: high pressure and temperature - gas, low indicators - oil.
Today, the main gas fields and reserves are owned by such countries as Russia, the USA, Canada, Iran, Norway and the Netherlands.
According to its state of aggregation, natural gas cannot always be contained only in the state of gas. There are several options for its condensation:
- Gas is dissolved in oil molecules.
- The gas is dissolved in water molecules.
- The gas forms solid gas hydrates.
- Under normal conditions - a gaseous compound.
Each of these states has its own deposit and is very valuable for a person.
Obtaining in laboratory and industry
In addition to natural places of gas formation, there are a number of ways to get it in the laboratory. However, these methods, of course, are used only for small portions of the product, since it is not economically profitable to carry out the synthesis of natural gas in the laboratory.
Laboratory methods:
- Hydrolysis of a low molecular weight compound - aluminum carbide: AL 4 C 3 + 12H 2 O \u003d 3CH 4 + 4AL (OH) 3.
- From sodium acetate in the presence of alkali: CH 3 COOH + NaOH = CH 4 + Na 2 CO 3.
- From synthesis gas: CO + 3H 2 \u003d CH 4 + H 2 O.
- From simple substances - hydrogen and carbon - at elevated temperature and pressure.
The chemical formula of natural gas is reflected by the formula of methane, so everything is for this gas.
In industry, methane is obtained by extraction from natural deposits and further processing by fractions. Also, the resulting gas must be purified. After all, the formula of natural gas methane shows only a part of those components that it contains. And for domestic use, you need a clean gas that does not contain other substances except methane. Separated ethane, propane, butane and other gases are also widely used.
Physical Properties
The formula of a gas gives an idea of what physical properties it should have. Let's take a look at what these features are.
- A colorless, odorless substance.
- The approximate density varies between 0.7-1 kg / m 3.
- Burning temperature 650 0 С.
- Almost twice as light as air.
- The heat released during the combustion of one cubic meter of gas is 46 million Joules.
- At elevated concentrations (over 15%) in air, the gas is highly explosive.
- When used as a fuel, it exhibits an octane rating of 130.
Pure gas is obtained only after passing it through special treatment plants(installations), which are erected at the place of extraction of the mineral.
Application
There are several main applications for natural gas. Indeed, in addition to its main component, the gas formula of which is CH 4, all other components of the mixture are used.
1. Domestic sphere of people's lives. This includes gas for cooking, heating residential buildings, fuel for boilers, and so on. In the gas that is used for cooking, add special substances belonging to the group of mercaptans. This is done so that in the event of a pipe leak or other omission of gas, people can smell it and take action. A mixture of household gas (and this is a mixture of propane and butane) is extremely explosive in high concentrations. Mercaptans, on the other hand, make natural gas specific and odorless. Their formula includes elements such as sulfur and phosphorus, which gives them such specificity.
2. Chemical production. In this area, one of the main initial substances for many reactions of obtaining important compounds is natural gas, the formula of which shows in which syntheses it can take part:
- basis in the production of plastics, which are the most common modern material for almost all industries;
- raw material in the synthesis of ethine, hydrogen cyanide and ammonia. The listed products themselves are further used in the production of many synthetic fibers and fabrics, fertilizers and insulation in construction;
- rubber, methanol, organic acids - are formed from methane and other substances. They find application in almost all spheres of human life;
- polyethylene and many other synthetic compounds were obtained thanks to methane.
3. Use as a fuel. Moreover, for any type of human activity, starting from refueling of the appropriate type table lamps and before the operation of thermal power plants. This type fuel is considered environmentally correct and expedient against the backdrop of all alternative methods. However, when burned, methane forms carbon dioxide, like any other organic substance. And he, as you know, is the cause of the greenhouse effect of the Earth. Therefore, people are faced with the task of finding an even cleaner and better source of thermal energy.
So far, these are all the main sources that use natural gas. Its formula, if we take all the complex components, shows that it is a practically renewable resource, only it takes a lot of time for this. Our country is extremely lucky with gas reserves, because such a quantity of natural resources will last for many hundreds of years, not only for Russia itself, but also for many countries of the world through export.
Nitrogen
Is an integral part oil and gas natural fields. In addition, this gas takes most volume in the air (78%), and also occurs in the form of natural saltpeter compounds in the lithosphere.
As a simple substance, nitrogen is practically not used by living organisms. Its formula has the form N 2 , or, in terms of chemical bonds, N≡N. The presence of such a strong bond indicates the high stability and chemical inertness of the molecule under normal conditions. This explains the possibility of the existence of a large amount of this gas in free form in the atmosphere.
In the form of a simple substance, nitrogen is able to be fixed by special organisms - nodule bacteria. They then process this gas into a more suitable form for plants and thus carry out mineral nutrition of plant root systems.
There are several basic compounds in the form of which nitrogen exists in nature. Their formula is as follows:
- oxides - NO 2, N 2 O, N 2 O 5;
- acids - nitrous HNO 2 and nitric HNO 3 (formed during lightning discharges from oxides in the air atmosphere);
- saltpeter - KNO 3, NaNO 3 and so on.
Man uses nitrogen not only in but also in the liquid state. It has the ability to pass into a liquid state at temperatures below -170 0 C, which allows it to be used for freezing plant and animal tissues, many materials. That is why liquid nitrogen is widely used in medicine.
Nitrogen is also the basis for obtaining one of its main compounds - ammonia. Production given substance large-tonnage, as it is very widely used in everyday life and industry (obtaining rubbers, dyes, plastics, synthetic fibers, organic acids, paint and varnish production, explosives, and so on).
Carbon dioxide
What is the formula of the substance? Carbon dioxide is written as CO 2 . The bond in the molecule is covalent, weakly polar, double strong chemical forces between carbon and oxygen. This indicates the stability and inertness of the molecule under normal conditions. This fact is confirmed by the free existence of carbon dioxide in the Earth's atmosphere.
This substance is an integral part of natural gas and oil, and also accumulates in the upper atmosphere of the planet, causing the so-called greenhouse effect.
A huge amount of carbon dioxide is formed during the combustion of any type of organic fuel. Whether it is coal, wood, gas or other fuel, complete combustion results in the formation of water and this substance.
Hence, it turns out that its accumulation in the atmosphere is inevitable. Therefore, an important task modern society is the search for an alternative fuel that gives a minimum of the greenhouse effect.
Hydrogen
Another associated compound found in natural minerals is hydrogen. A gas whose formula is H 2. The lightest substance known to date.
Thanks to their special properties ranks in periodic system two positions - among alkali metals and halogens. Having one electron, it is capable of both giving it away (metallic properties, reducing) and accepting it (non-metallic properties, oxidizing).
The main area of use is environmentally friendly fuel, for which scientists see the future. Causes:
- unlimited reserves of this gas;
- formation as a result of combustion of only water.
However, the full technology for the development of hydrogen as an energy source still needs to be refined in many more nuances.
Formulas for calculating the mass, density and volume of gases
In physics and chemistry, several basic methods are used to calculate gases. So, for example, if we are talking about one of the most basic parameters, such as the mass of gas, the formula for calculating will be as follows:
m = V*þ, where þ is the density of the substance, and V is its volume.
For example, if we need to calculate the mass of natural gas with a volume of 1 cubic meter under normal conditions, then we take the standard average value of its density in reference materials. It will be equal to 0.68 kg / m 3. Now that we know the volume and density of the gas, the calculation formula is quite satisfactory. Then:
m (CH 4) \u003d 0.68 kg / m 3 * 1 m 3 \u003d 0.68 kg, since cubic meters are reduced.
The formula for the volume of a gas, on the contrary, is the sum of the mass and density indicators. That is, we can express this value from the configuration above:
V \u003d m / þ, then under standard conditions the volume of 2 kg of methane will be equal to: 2 / 0.68 \u003d 2.914 m 3.
Also, in more complex cases (when the conditions are non-standard), to calculate the mass and volume of gases, the Mendeleev-Clapeyron equation is used, which has the form:
p*V = m/M*R*T, where p is the gas pressure, V is its volume, m and M are the mass and molar mass, respectively, R is the universal gas constant equal to 8.314, T is the temperature in Kelvin.
This formula for the volume of gas makes it possible to obtain calculations that are very close to the value ideal gas, which exists purely hypothetically and is used to abstract concept when solving problems in physics and chemistry. You can also calculate the volume using the Boyle-Mariotte equation, which has the form:
V=p n *V n *T/p*T n, where values with index n are values under normal standard conditions.
In order for the calculation to be as accurate as possible and correspond to reality, it is necessary to take into account such a parameter as The formula for calculating this parameter is still a moot point. It is customary to use the most common simple one, which looks like:
þ \u003d m 0 * n, where m 0 is the mass of the molecule (kg), and n is the concentration, the unit of measurement is 1 / m 3.
However, in some cases it is necessary to use other, more complex and complete calculations with multiple variables to get accurate and close to perfect results.
Mankind has known about the existence of natural gas for a long time. According to the most conservative estimates, natural gas was used in China for heating and lighting as early as the 4th century BC. To obtain it, wells were drilled, and pipelines were made of bamboo. Moreover, for a long time a bright flame that does not leave ashes was the subject of a mystical and religious cult for some peoples. For example, on the Absheron Peninsula ( modern territory Azerbaijan) in the 7th century, a temple of fire worshipers Ateshgah was erected, services in which took place until the 19th century.
The word "gas" itself was coined at the beginning of the 17th century by the Flemish naturalist Jan Baptist van Helmont to refer to the "dead air" (carbon dioxide) he received. Helmont wrote: "I called such steam gas, because it almost does not differ from the chaos of the ancients." But in this case, we are dealing with one of the forms of the existence of matter.
There is still no consensus among scientists regarding the origin of natural gas. Two basic concepts - biogenic and mineral - state different reasons formation of hydrocarbon minerals in the bowels of the Earth.
- mineral theory. Formation of minerals in seams rocks- part of the process of degassing of the Earth. Due to the internal dynamics of the Earth, hydrocarbons found on great depths, rise to the zone of least pressure, forming gas deposits as a result.
- Biogenic theory. Living organisms that died and sank to the bottom of water bodies decomposed in an airless space. Sinking deeper and deeper due to geological movements, the remains of decomposed organic matter turned under the influence of thermobaric factors (temperature and pressure) into hydrocarbon minerals, including natural gas.
Relatively recently, a group of scientists from the Institute of Oil and Gas Problems of the Russian Academy of Sciences, led by Doctor of Geological and Mineralogical Sciences Azariy Barenbaum, developed a new concept of the origin of oil and gas. According to this theory, large deposits of hydrocarbons can arise not over millions of years, as previously thought, but only over decades.
Natural gas can exist in the form of gas deposits located in the layers of certain rocks, in the form of gas caps (above oil), as well as in dissolved or crystalline form. Also, natural gas can be in the form of gas hydrates (natural gas hydrates are gas hydrates or clathrates - crystalline compounds formed under certain thermobaric conditions from water and gas).
Natural gas has a number of advantages over other fuels and feedstocks:
- the cost of extracting natural gas is much lower than other types of fuel; labor productivity in its extraction is higher than in the extraction of oil and coal;
- the absence of carbon monoxide in natural gases prevents the possibility of poisoning people with gas leaks;
- at gas heating cities and settlements the air basin is much less polluted;
- when working on natural gas, it is possible to automate combustion processes, high efficiency is achieved;
- high temperatures during combustion (over 2000°C) and specific heat combustion allow efficient use of natural gas as an energy and process fuel.
Gas is a younger fuel than oil. The era of natural gas, in fact, began with the discovery in 1959 of the Groningen field in the Netherlands and the subsequent discovery of gas reserves by Great Britain in the southern North Sea basin in the mid-1960s.
According to the IEA, since the early 70s. the share of gas in the global energy balance increased from 16% to 21% in 2008. According to the BP Statistical Review of World Energy, this share in 2008-2010. in world energy consumption was even higher - about 24%. BP's Global Energy Outlook 2030 study states that natural gas will be the fastest growing fuel in the next 25 years. At the same time, experts from the International Energy Agency believe that the share of gas in the global energy balance will increase from 21% to 25% by 2035, gas will become the second energy carrier after oil, displacing coal to third place.
The chemical composition of natural gas is quite simple. The main part of this type of gas is methane (CH4) - the simplest hydrocarbon (an organic compound consisting of carbon and hydrogen atoms), its share exceeds 92%.
Depending on the content of methane, two main groups of natural gas are distinguished:
- Natural gas group H(H-gas, i.e. high-calorie gas) due to the high content of methane (from 87% to 99%) is the highest quality. Russian natural gas belongs to the H group and has a high calorific value. Due to its high content of methane (~98%), it is the highest quality natural gas in the world.
- Natural gas group L(L-gas, i.e. low-calorie gas) is natural gas with a lower methane content - from 80% to 87%. If the quality requirements are not met (11.1 kWh/m3), then often the gas cannot be delivered directly to the end user without additional processing.
In addition to methane, natural gas may contain heavier hydrocarbons, methane homologues: ethane (C2H6), propane (C3H8), butane (C4H10) and some non-hydrocarbon impurities. At the same time, it is important that the composition of natural gas is not constant and varies from field to field.
Approximate physical characteristics (depending on the composition):
- Density: from 0.7 to 1.0 kg/m3 (dry gaseous, under normal conditions) or 400 kg/m3 (liquid).
- Ignition temperature: t = 650°C.
- The heat of combustion of one m3 of natural gas in the gaseous state at n.c.: 28-46 MJ, or 6.7-11.0 Mcal.
- Octane number when used in internal combustion engines: 120-130.
- It is 1.8 times lighter than air, therefore, when leaking, it does not collect in the lowlands, but rises up.
Application
With advantages over other energy carriers such as economy and environmental friendliness, natural gas is becoming increasingly important in industry and households.
Natural gas as a fossil energy carrier is mainly used for heating residential and industrial premises, for cooking, power generation, as well as in the industrial sector for the generation of thermal energy.
Natural gas is used to a small extent as a motor fuel. Due to the rise in gasoline prices for last years and for months the number of private vehicles converted to gas engines has increased. In addition, trucks and buses are being re-equipped to run on natural gas. Along with the cost factor, an important argument in favor of natural gas is the lower level of emissions to the atmosphere harmful substances.
Top 20 world countries in terms of proven gas reserves (according to the results of 2010)
| The country | Stocks (trillion cubic meters) | Share of global (%) | |
| 1 | RF | 44,76 | 23,9 |
| 2 | Iran | 29,61 | 15,8 |
| 3 | Qatar | 25,32 | 13,5 |
| 4 | Turkmenistan | 8,03 | 4,3 |
| 5 | Saudi Arabia | 8,01 | 4,3 |
| 6 | USA | 7,71 | 4,1 |
| 7 | UAE | 6,43 | 3,4 |
| 8 | Venezuela | 5,45 | 2,9 |
| 9 | Nigeria | 5,29 | 2,8 |
| 10 | Algeria | 4,50 | 2,4 |
| 11 | Iraq | 3,16 | 1,7 |
| 12 | Indonesia | 3,06 | 1,6 |
| 13 | Australia | 2,92 | 1,6 |
| 14 | China | 2,80 | 1,5 |
| 15 | Malaysia | 2,39 | 1,3 |
| 16 | Egypt | 2,21 | 1,2 |
| 17 | Norway | 2,04 | 1,1 |
| 18 | Kazakhstan | 1,84 | 1 |
| 19 | Kuwait | 1,78 | 1 |
| 20 | Canada | 1,72 | 0,9 |
A source
Top 20 countries in the world in terms of gas consumption (according to the results of 2010)
| The country | Consumption (billion cubic meters) | Share of global (%) | |
| 1 | USA | 683,4 | 21,7 |
| 2 | RF | 414,1 | 13 |
| 3 | Iran | 136,9 | 4,3 |
| 4 | China | 109,0 | 3,4 |
| 5 | Japan | 94,5 | 3 |
| 6 | Great Britain | 93,8 | 3 |
| 7 | Canada | 93,8 | 3 |
| 8 | Saudi Arabia | 83,9 | 2,6 |
| 9 | Germany | 81,3 | 2,6 |
| 10 | Italy | 76,1 | 2,4 |
| 11 | Mexico | 68,9 | 2,2 |
| 12 | India | 61,9 | 1,9 |
| 13 | UAE | 60,5 | 1,9 |
| 14 | Ukraine | 52,1 | 1,6 |
| 15 | France | 46,9 | 1,5 |
| 16 | Uzbekistan | 45,5 | 1,4 |
| 17 | Egypt | 45,1 | 1,4 |
| 18 | Thailand | 45,1 | 1,4 |
| 19 | Netherlands | 43,6 | 1,4 |
| 20 | Argentina | 43,3 | 1,4 |
A source: BP Statistical Review of World Energy 2011
20 leading countries in the world in terms of gas production (according to the results of 2010)
| The country | Mining (billion cubic meters) | Share of global (%) | |
| 1 | USA | 611 | 19,3 |
| 2 | Russia | 588,9 | 18,4 |
| 3 | Canada | 159,8 | 5 |
| 4 | Iran | 138,5 | 4,3 |
| 5 | Qatar | 116,7 | 3,6 |
| 6 | Norway | 106,4 | 3,3 |
| 7 | China | 96,8 | 3 |
| 8 | Saudi Arabia | 83,9 | 2,6 |
| 9 | Indonesia | 82 | 2,6 |
| 10 | Algeria | 80,4 | 2,5 |
| 11 | Netherlands | 70,5 | 2,2 |
| 12 | Malaysia | 66,5 | 2,1 |
| 13 | Egypt | 61,3 | 1,9 |
| 14 | Uzbekistan | 59,1 | 1,8 |
| 15 | Great Britain | 57,1 | 1,8 |
| 16 | Mexico | 55,3 | 1,7 |
| 17 | UAE | 51 | 1,6 |
| 18 | India | 50,9 | 1,6 |
| 19 | Australia | 50,4 | 1,6 |
| 20 | Trinidad and Tobago | 42,4 | 1,3 |
A source: BP Statistical Review of World Energy 2011
There is a mixture of methane CH 4 with a small amount of nitrogen N 2 and carbon dioxide CO 2 - that is, that it is qualitatively identical in composition with the gas emitted from swamps.
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Subtitles
Chemical composition
The main part of natural gas is methane (CH 4) - from 70 to 98%. The composition of natural gas may include heavier hydrocarbons - methane homologues:
- ethane (C 2 H 6),
- propane (C 3 H 8),
- butane (C 4 H 10).
Natural gas also contains other substances that are not hydrocarbons:
- helium (He) and other inert gases.
Pure natural gas is colorless and odorless. To facilitate the possibility of determining the leakage of gas into it in not in large numbers add odorants - substances that have a sharp bad smell(rotten cabbage, rotten hay, rotten eggs). The most commonly used odorants are thiols (mercaptans), such as ethyl mercaptan (16 g per 1000 m³ of natural gas).
Physical Properties
Approximate physical characteristics (depending on the composition; under normal conditions, unless otherwise indicated):
Natural gas fields
Huge deposits of natural gas are concentrated in the sedimentary shell of the earth's crust. According to the theory of the biogenic (organic) origin of oil, they are formed as a result of the decomposition of the remains of living organisms. It is believed that natural gas is formed in the sedimentary shell at higher temperatures and pressures than oil. Consistent with this is the fact that gas fields are often deeper than oil fields.
Huge reserves of natural gas are possessed by Russia (Urengoyskoye field), Iran, most of the countries of the Persian Gulf, the USA, Canada. From European countries it is worth noting Norway, the Netherlands. Among former republics Soviet Union large gas reserves are owned by Turkmenistan, Azerbaijan, Uzbekistan, and Kazakhstan (Karachaganak field).
Methane and some other hydrocarbons are widely distributed in space. Methane is the third most abundant gas in the universe, after hydrogen and helium. In the form of methane ice, it is involved in the structure of many planets and asteroids distant from the sun, however, such accumulations, as a rule, are not classified as natural gas deposits, and they have not yet been found. practical application. A significant amount of hydrocarbons is present in the Earth's mantle, but they are also of no interest.
Gas hydrates
In science, it has long been believed that accumulations of hydrocarbons with a molecular weight of more than 60 are in the earth's crust in a liquid state, while lighter ones are in a gaseous state. However, in the second half of the 20th century, a group of researchers A. A. Trofimuk, N. V. Chersky, F. A. Trebin, Yu. earth's crust into a solid state and form gas hydrate deposits. Later it turned out that the reserves of natural gas in this state are huge.
The gas passes into a solid state in the earth's crust, connecting with formation water at hydrostatic pressures up to 250 atm and relatively low temperatures(up to +22 °C ). Gas hydrate deposits have an incomparably higher concentration of gas per unit volume of the porous medium than in ordinary gas deposits, since one volume of water binds up to 220 volumes of gas when it passes into the hydrated state. The zones of gas hydrate deposits are concentrated mainly in the areas of permafrost distribution, as well as at a shallow depth under the ocean floor.
Natural gas reserves
Extraction and transportation
Natural gas is found in the ground at depths ranging from 1,000 m to several kilometers. Super deep well near the city of Novy Urengoy, a gas inflow was received from a depth of more than 6,000 meters. In the bowels of the gas is in microscopic voids (pores). The pores are interconnected by microscopic channels - cracks, through these channels the gas comes from the pores with high pressure into lower pressure pores until it is in the well. The movement of gas in a reservoir obeys certain laws.
Gas is extracted from the bowels of the earth with the help of wells. Wells are trying to be placed evenly throughout the field, for a uniform drop in reservoir pressure in the deposit. Otherwise, gas flows between areas of the deposit are possible, as well as premature flooding of the deposit.
Gas comes out of the bowels due to the fact that in the reservoir it is under pressure many times higher than atmospheric pressure. Thus, the driving force is the pressure difference between the reservoir and the collection system.
World natural gas production in 2014 amounted to 3460.6 bcm. The leading position in gas production is occupied by Russia and the United States.
| The country | 2010 | 2006 | ||
| Mining, billion m³ |
Share of world market (%) |
Mining, billion m³ |
Share of world market (%) |
|
| Russia | 647 | 673,46 | 18 | |
| USA | 619 | 667 | 18 | |
| Canada | 158 | |||
| Iran | 152 | 170 | 5 | |
| Norway | 110 | 143 | 4 | |
| China | 98 | |||
| Netherlands | 89 | 77,67 | 2,1 | |
| Indonesia | 82 | 88,1 | 2,4 | |
| Saudi Arabia | 77 | 85,7 | 2,3 | |
| Algeria | 68 | 171,3 | 5 | |
| Uzbekistan | 65 | |||
| Turkmenistan | 66,2 | 1,8 | ||
| Egypt | 63 | |||
| Great Britain | 60 | |||
| Malaysia | 59 | 69,9 | 1,9 | |
| India | 53 | |||
| UAE | 52 | |||
| Mexico | 50 | |||
| Azerbaijan | 41 | 1,1 | ||
| Other countries | 1440,17 | 38,4 | ||
| World gas production | 100 | 3646 | 100 | |
Preparation of natural gas for transportation
The gas coming from the wells must be prepared for transportation to the end user - a chemical plant, boiler room, CHP, city gas networks. The need for gas preparation is caused by the presence in it, in addition to the target components (different components are targeted for different consumers), also impurities that cause difficulties during transportation or use. Thus, water vapor contained in a gas, under certain conditions, can form hydrates or, condensing, accumulate in various places(for example, bending of the pipeline), interfering with the advancement of gas; hydrogen sulfide is highly corrosive gas equipment(pipes, heat exchanger tanks, etc.). In addition to preparing the gas itself, it is also necessary to prepare the pipeline. Nitrogen plants are widely used here, which are used to create an inert atmosphere in the pipeline.
Gas is prepared according to various schemes. According to one of them, a plant is being built in the immediate vicinity of the field. integrated training gas (GTP), where gas is cleaned and dried in absorption columns. Such a scheme has been implemented at the Urengoyskoye field. Gas treatment by membrane technology is also expedient.
To prepare gas for transportation, technological solutions using membrane gas separation, which can isolate heavy hydrocarbons (C 3 H 8 and above), nitrogen, carbon dioxide, hydrogen sulfide, and also significantly reduce the dew point temperature for water and hydrocarbons before being fed into the GTS.
If the gas contains a large amount of helium or hydrogen sulfide, then the gas is processed at a gas processing plant, where sulfur is isolated at amine treatment plants and Claus plants, and helium at cryogenic helium plants (CGU). This scheme has been implemented, for example, at the Orenburg field. If the hydrogen sulfide content in the gas is less than 1.5% by volume, then it is also advisable to consider the membrane technology for natural gas treatment, since its use allows reducing capital and operating costs by 1.5-5
Natural gas transportation
Currently, the main mode of transport is pipeline. Gas at a pressure of 75 atm is pumped through pipes up to 1.42 m in diameter. As the gas moves through the pipeline, it, overcoming friction forces both between the gas and the pipe wall and between the gas layers, loses potential energy, which is dissipated in the form of heat. Therefore, at certain intervals, it is necessary to build compressor stations (CS), in which the gas is usually boosted to a pressure of 55 to 120 atm and then cooled. The construction and maintenance of the pipeline is very expensive, but nevertheless it is the cheapest way to transport gas over short and medium distances in terms of initial investment and organization.
In addition to pipeline transport, special gas carriers are widely used. These are special vessels on which gas is transported in a liquefied state in specialized isothermal tanks at a temperature of -160 to -150 °C.
For liquefaction, the gas is cooled at high blood pressure. At the same time, the compression ratio reaches 600 times, depending on the needs. Thus, to transport gas in this way, it is necessary to stretch a gas pipeline from the field to the nearest sea coast, build a terminal on the coast, which is much cheaper than a conventional port, to liquefy gas and pump it into tankers, and the tankers themselves. The usual capacity of modern tankers is between 150,000 and 250,000 m³. This method of transportation is much more economical than pipeline transportation, starting from the distances to the consumer. liquefied gas more than 2000-3000 km, since the main cost is not transportation, but loading and unloading, but it requires higher initial investments in infrastructure than pipelines. Its advantages also include the fact that liquefied gas is much safer during transportation and storage than compressed gas.
In 2004, international gas supplies through pipelines amounted to 502 billion m³, liquefied gas - 178 billion m³.
There are also other technologies for transporting gas, for example, using railway tanks.
Gas transportation projects were also developed using
Natural gas is a mixture of such gases that were formed in the bowels of the earth during the decomposition of various organic substances. Of course, the composition of natural gas should be adjusted for specific samples. However, all natural gases undoubtedly have many common substances and chemical elements in the structure, and also any natural gas has approximately the same physical composition and properties as others. We will talk about this with you.
General information
Natural gas is one of the most important minerals actively used in industry and in everyday life. Under conditions of occurrence (or, as gasmen say, in reservoir conditions), natural gas is exclusively in a gaseous state, either in the form of a so-called "gas cap" in common oil and gas fields, or in the form of gas deposits (that is, individual accumulations), or dissolved in water or oil. True, under certain conditions, natural gas can be not only in a gaseous state, but also in a solid state in the form of crystals.
Chemical composition of natural gas
As for the main substances that make up natural gas, they are methane (CH 4), carbon dioxide (CO 2) and nitrogen in the form of molecules (N 2). Almost any natural gas, whether mine or swamp, consists of these substances and elements. As for the composition of natural gas as a percentage, the main substance that makes up natural gas is certainly methane. Its share is from 90 to 98% - depending on the gas field. Natural gas also contains substances such as butane, propane, ethane (hydrocarbons, also called methane homologues, since they consist of the same chemical elements, differing only in the number of carbon and hydrogen atoms and, accordingly, in the structure of molecules). Of the non-hydrocarbon components of natural gas, we note, in addition to the already described nitrogen and carbon dioxide (carbon dioxide), hydrogen (H 2), helium (He) and hydrogen sulfide (H 2 S).
Physical properties of natural gas
First of all, we note that natural gas, which is in its pure form, is colorless and odorless. In order to determine the leakage of gas, so-called odorants or substances that have a sharp and rather unpleasant odor are added to it in small quantities: for example, thiols, among which ethyl mercaptan occupies a leading position. For 1000 cubic meters of natural gas, usually no more than 15-16 g of ethyl mercaptan is added. The density of natural gas in its gaseous state is on average 0.75 kg per cubic meter. In the crystalline state, the density reaches 400 kg per m 3. Natural gas ignites spontaneously only at a very high temperature - about 650 degrees Celsius. At a certain concentration of natural gas in the air (approximately 5-15%), explosions can occur. Also known is the specific heat of combustion of natural gas, which averages 35 MJ/m? or 9 Mcal/m?. When used in various internal combustion engines, natural gas has an octane rating of 120 to 130. Finally, natural gas is about 1.8 times lighter than air, so it rises when it leaks rather than pooling in lowlands.
Application of natural gas
First of all, natural gas modern world used as fuel and fuel. So, in many multi-apartment and private houses, people use natural gas for cooking, heating water, and heating. As for other uses of natural gas as a fuel, in Lately it is actively used not only as a fuel for various thermal power plants and boiler houses, but also as a fuel for the fuel systems of some cars. In addition, modern engineers and designers have even launched the production of vehicles running on natural gas - for example, buses. V chemical industry natural gas is used as a raw material for the manufacture of all kinds of substances - for example, various plastics and plastics. And in the early days of its production, many European and North American cities used natural gas as a street lighting and it was used even in the very first traffic lights.
Natural gas, which we are all so accustomed to in our kitchens, is a close relative of oil. It consists mostly of methane with impurities of heavier hydrocarbons (ethane, propane, butane). Under natural conditions, it also often contains impurities of other gases (helium, nitrogen, hydrogen sulfide, carbon dioxide).
Typical composition of natural gas:
hydrocarbons:
- Methane - 70-98%
- Ethane - 1-10%
- Propane - up to 5%
- Butane - up to 2%
- Pentane - up to 1%
- Hexane - up to 0.5%
impurities:
- Nitrogen - up to 15%
- Helium - up to 5%
- Carbon dioxide - up to 1%
- Hydrogen sulfide - less than 0.1%
Natural gas is extremely widespread in the bowels of the earth. It can be found in the thickness of the earth's crust at a depth of several centimeters to 8 kilometers. As well as oil, natural gas, in the process of migration in the earth's crust, falls into traps (permeable layers limited by an impermeable rock mass), as a result of which gas fields are formed.
Five largest gas fields in Russia:
- Urengoy (gas)
- Yamburgskoye (oil and gas condensate)
- Bovanenkovo (oil and gas condensate)
- Shtokmanovskoye (gas condensate)
- Leningrad (gas)
Natural (hydrocarbon) gas is a frequent companion of oil fields. It is usually contained in oil in dissolved form, and in some cases accumulates in the upper part of the deposits, forming the so-called gas cap. For a long time, the gas released during oil production, called associated gas, was an undesirable component of the extraction process. Most often it was simply burned in torches.
Only in the last few decades, mankind has learned to fully use all the advantages of natural gas. Such a delay in the development of this extremely valuable type of fuel is largely due to the fact that the transportation of gas and its use in industry and everyday life require a fairly high technical and technological level of development. In addition, natural gas, when mixed with air, forms an explosive mixture, which requires increased safety measures when using it.
Gas application
Some attempts to use gas were made as early as the 19th century. Luminous gas, as it was then called, served as a source of illumination. The development of gas fields at that time was not yet carried out, and gas produced together with oil was used for lighting. Therefore, such gas is often called oil. Such oil gas, for example, has long illuminated Kazan. It was also used to illuminate St. Petersburg and Moscow.
Nowadays, gas is playing an increasingly significant role in the world's energy sector. The range of its application is very wide. It is used in industry, at home, in boiler houses, thermal power plants, as a motor fuel for cars and as a feedstock in the chemical industry.
Gas is considered a relatively clean fuel. When gas is burned, only carbon dioxide and water are produced. At the same time, carbon dioxide emissions are almost two times less than when burning coal and 1.3 times less than when burning oil. Not to mention the fact that when oil and coal are burned, soot and ash remain. Due to the fact that of all fossil fuels, gas is the most environmentally friendly type, it occupies a dominant position in the energy of modern megacities.
How gas is produced
Just like oil, natural gas is extracted using wells, which are distributed evenly over the entire area of the gas field. Production occurs due to the pressure difference in the gas-bearing reservoir and on the surface. Under the action of reservoir pressure, the gas is pushed through the wells to the surface, where it enters the collection system. Further, the gas is fed to the complex gas treatment plant, where it is purified from impurities. If there is a small amount of impurities in the produced gas, then it can be immediately sent to the gas processing plant, bypassing the complex treatment unit.
How gas is transported
Gas is transported mainly through pipelines. The main volumes of gas are transported by main gas pipelines, where the gas pressure can reach 118 atm. Consumers get gas through distribution and intra-house gas pipelines. First, the gas passes through the gas distribution station, where its pressure is reduced to 12 atm. Then, through gas distribution pipelines, it is supplied to gas control points, where its pressure is again lowered, this time to 0.3 atm. After that, through the intra-house gas pipelines, the gas enters our kitchen.
All this huge gas distribution infrastructure is a truly large-scale picture. Hundreds and hundreds of thousands of kilometers of gas pipelines that have entangled almost the entire territory of Russia. If all this web of gas pipelines is stretched in one line, then its length will be enough to get from the Earth to the Moon and back. And this is only the gas transportation system of Russia. If we talk about the entire global gas transportation infrastructure, then we will talk about millions of kilometers of pipelines.
Since natural gas has neither odor nor color, in order to be able to quickly detect gas leaks, it is artificially given an unpleasant odor. This process is called odorization and takes place at gas distribution stations. Sulfur-containing compounds, such as ethanethiol (EtSH), are commonly used as odorants, that is, unpleasant smelling substances.
Gas consumption is seasonal. In winter, its consumption increases, and in summer it decreases. To smooth out seasonal fluctuations in gas consumption, underground gas storage facilities (UGS) are being built near large industrial centers. These may be depleted gas fields adapted for gas storage or artificially created underground salt caves. In summer, the surplus of transported gas is sent to underground storage facilities, and in winter, on the contrary, a possible lack of capacity of the pipeline system is compensated by gas withdrawal from storage facilities.
In world practice, in addition to gas pipelines, natural gas is often transported in liquefied form via special courts– gas carriers (methane carriers). In liquefied form, the volume of natural gas is reduced by 600 times, which is convenient not only for transportation, but also for storage. For liquefaction, the gas is cooled to the condensation temperature (-161.5 ° C), as a result of which it turns into a liquid. In such a chilled form, it is transported. The main producers of liquefied natural gas are Qatar, Indonesia, Malaysia, Australia and Nigeria.
Outlook and trends
Due to its environmental friendliness and the constant improvement of technology and technology, both in the production and use of gas, this type of fuel is becoming increasingly popular. BP, for example, forecasts demand for gas to outpace other fossil fuels.
The growing demand for gas leads to the search for new, often unconventional, sources of gas. These sources can be:
- Coal bed gas
- Shale gas
- Gas hydrates
♦ Coal bed gas mining began only in the late 1980s. This was first done in the USA, where the commercial feasibility of this type of mining has been proven. In Russia, Gazprom began testing this method in 2003, when it began trial production of coal-bed methane in Kuzbass. Gas production from coal seams is also carried out in other countries - Australia, Canada and China.
♦ Shale gas. The shale revolution in gas production that has taken place in the United States in the past decade has been on the front pages of periodicals. The development of horizontal drilling technology has made it possible to extract gas from low-permeability shale in volumes that pay back the costs of its extraction. The phenomenon of the rapid development of shale gas production in the United States is spurring other countries to develop this direction. In addition to the United States, active work on the extraction of shale gas is being carried out in Canada. China also has significant potential for the development of large-scale shale gas production.
♦ Gas hydrates. A significant part of natural gas is in a crystalline state in the form of so-called gas hydrates (methane hydrates). Large reserves of gas hydrates exist in the oceans and in the permafrost zones of the continents. Estimated gas hydrate reserves currently exceed the combined reserves of oil, coal and conventional gas. The development of economically viable technologies for the extraction of gas hydrates is being intensively pursued in Japan, the USA and some other countries. Japan pays special attention to this topic, deprived of traditional gas reserves and forced to purchase this type of resource at extremely high prices.
Natural gas as a fuel and a source of chemical elements has a great future. In the long term, it is it that is considered as the main type of fuel that will be used during the transition of the world energy sector to cleaner renewable resources.