Gas condensate: types, properties and processing. Natural gas Gas condensate application

Gas condensate is a colorless or slightly colored liquid. In natural conditions (in deposits), as a rule, it is located in gaseous state. Condenses from natural (reservoir) gases with increasing pressure (above dew point pressure) and/or a decrease in temperature ( hydrocarbon dew point). It consists of gasoline (boiling range from 30-80 to 200°C), kerosene (200-300°C) and, to a lesser extent, higher boiling components. For most gas condensates, the yield of gasoline fractions is 70-85%.

Depending on the presence/absence of gases in the product, they distinguish unstable gas condensate (raw gas condensate), which contains dissolved gases, and stable gas condensate , obtained by degassing the unstable (mainly by rectification).

In its turn stable condensate depending on the place of production it is divided into field condensate (lease condensate- English), obtained directly in the field, next to the well, and factory condensate (plant condensate- English), produced at gas processing plants.

Source

When the pressure decreases, as gas is consumed, gas condensate is released in the geological formation and disappears for the consumer. Therefore, when exploiting fields with a high content of gas condensate, hydrocarbons C 3 and higher are released from the gas produced to the surface of the earth, and the C 1 -C 2 fraction is pumped back in to maintain pressure in the formation.

Resources and reserves

At the beginning of 2013, promising resources (C3) and proven recoverable reserves (A+B+C1) of gas condensate in Russia were estimated at 2 billion tons.

Accumulation when using gas engines

Gas condensate can accumulate in automotive gas equipment. The liquid is brownish-brown in color, has an unpleasant, corrosive odor of benzene resins (depending on the composition of the gas combustible mixture) and can have a range of odors from a sharp acetone to the smell of tobacco smoke (this depends on the composition of the additives that are added to make the gas smell). It is recommended to drain the gas reducer regularly. It is advisable not to touch it with your hands, because... it can be dangerous to your health.

) and temperature, some gasoline and kerosene fractions and, less commonly, higher molecular weight liquid components of oil are in a vapor state. When developing fields, the pressure drops several times - to 4-8 MPa, and a raw, unstable condensate is released from the gas, which, in contrast to the stable one, contains not only hydrocarbons C 5 and higher, but also dissolved gases of the methane-butane fraction.

Resources and reserves

At the beginning of 2013, promising resources (C3) and proven recoverable reserves (A+B+C1) of gas condensate in Russia were estimated at 2 billion tons.

Accumulation when using gas engines

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// Geology, geography and global energy. 2013. No. 2 (49)

Fossil

Oil and petroleum products

Renewable
and biological

Artificial

An excerpt characterizing Gas condensate

Rostov saw the tears filling the sovereign’s eyes, and heard him, as he drove away, say in French to Czartoryski:
– What a terrible thing war, what a terrible thing! Quelle terrible chose que la guerre!
The vanguard troops positioned themselves in front of Wischau, in sight of the enemy line, which gave way to us at the slightest skirmish throughout the entire day. The sovereign's gratitude was expressed to the vanguard, rewards were promised, and a double portion of vodka was distributed to the people. Even more cheerfully than the previous night, the campfires crackled and soldiers' songs were heard.
That night Denisov celebrated his promotion to major, and Rostov, already quite drunk at the end of the feast, proposed a toast to the health of the sovereign, but “not the sovereign emperor, as they say at official dinners,” he said, “but to the health of the good sovereign, a charming and great man; We drink to his health and to a certain victory over the French!”
“If we fought before,” he said, “and did not give way to the French, as at Shengraben, what will happen now that he is ahead?” We will all die, we will die with pleasure for him. So, gentlemen? Maybe I'm not saying that, I drank a lot; Yes, I feel that way, and so do you. For the health of Alexander the First! Hurray!
- Hurray! – the inspired voices of the officers sounded.
And old captain Kirsten shouted with enthusiasm and no less sincerely than twenty-year-old Rostov.
When the officers drank and broke their glasses, Kirsten poured others and, in only a shirt and leggings, with a glass in his hand, approached the soldiers' fires and in a majestic pose, waving his hand upward, with his long gray mustache and white chest visible from behind his open shirt, stopped in the light of the fire.
- Guys, for the health of the Emperor, for victory over the enemies, hurrah! - he shouted in his brave, senile, hussar baritone.
The hussars crowded together and responded with a loud cry.
Late at night, when everyone had left, Denisov patted his favorite Rostov on the shoulder with his short hand.
“There’s no one to fall in love with on a hike, so he fell in love with me,” he said.
“Denisov, don’t joke about this,” Rostov shouted, “this is such a high, such a wonderful feeling, such...
- “We”, “we”, “d”, and “I share and approve” ...
- No, you don’t understand!
And Rostov got up and went to wander between the fires, dreaming about what happiness it would be to die without saving a life (he did not dare to dream about this), but simply to die in the eyes of the sovereign. He really was in love with the Tsar, and with the glory of Russian weapons, and with the hope of future triumph. And he was not the only one who experienced this feeling in those memorable days preceding the Battle of Austerlitz: nine-tenths of the people of the Russian army at that time were in love, although less enthusiastically, with their Tsar and with the glory of Russian weapons.

Stable gas condensate

A hydrocarbon liquid consisting of heavy hydrocarbons C 5+, in which no more than 2-3% of the mass is dissolved. propane-butane fraction. Two groups (I and II) of stable condensate have been established depending on the content of impurities - water, mechanical impurities, chloride salts.

In accordance with the OST 51.65 - 80 standard, stable condensate is defined as a mixture of methane, naphthenic and aromatic hydrocarbons that meets the requirements for a number of physicochemical parameters. The main indicator - saturated vapor pressure - at plus 38º C should be 66650 Pa (500 mm Hg). Thus, the vapor pressure of a stable condensate must be such that, at normal atmospheric pressure, it can be stored in a liquid state up to a temperature of the order of plus 60°C.

Properties of the transported fluid

The properties of oil that characterize the possibility of transportation through a pipeline or transportation in tanker tanks depend on its composition. The properties of oil are determined by the quantitative ratio between paraffin, naphthenic, aromatic hydrocarbons and other components. These properties must be taken into account at all stages of handling oil (and oil products):

· during commodity accounting operations;

· during pumping or transportation;

· when processed and used as fuel.

Density. Density usually varies from 650 to 920 kg/m3. The concept of relative density is also used, which is determined by the ratio of the density of liquid hydrocarbons to the density of water at 20°C. Accurate determination of the density of liquid hydrocarbons is of great commercial importance, since the volumes of the tanks used are well known, and this allows for more accurate determination of the commercial weight of the pumped product.

General property densities of liquid hydrocarbons - they decrease with increasing temperature (1 oil barrel = 42 gallons = 0.158988 m 3 = 159 l).

From the following graph it follows (see Fig. 2.) that for the considered oils, with an increase in temperature by 100 degrees. Celsius, their density decreases by 120-150 kg/m 3, i.e. by 15-18%.

Rice. 2.

The volumetric compression coefficient is a value that characterizes the change in the relative volume of a liquid when the pressure changes by one unit. The characteristic values of this coefficient for oil and condensate are in the range (5-15).10 - 4 1/MPa, i.e. these products have low compressibility.

Such large values of the volumetric compression ratio of oil and liquid hydrocarbons are responsible for strong hydraulic shocks in pipelines that occur when unsteadiness occurs during the movement of the transported product.

The general pattern is that the volumetric compression ratio decreases as the density of the liquid increases.

The coefficient of volumetric expansion is a value characterizing the relative change in the volume of a liquid when the temperature changes by 1º C.

Liquefied hydrocarbon gases have a particularly high coefficient of volumetric expansion among liquid hydrocarbons. At the same temperature increase, propane (butane) expands 16.1 (11.2) times more than water, and 3.2 (2.2) times more than a petroleum product such as kerosene.

As the temperature rises, LPG expands and creates dangerous stresses in the metal, which can lead to destruction of the tanks. This should be taken into account when filling the latter, maintaining the volume of the vapor phase required for safe operation, i.e. it is necessary to provide a steam "cushion". For tanks where the design temperature rise of the stored product does not exceed 40° C, the degree of filling is taken to be 0.85; with a larger design temperature difference, the degree of filling is taken to be even less.

The overwhelming majority of liquid hydrocarbons pumped in main pipelines under transportation conditions belong to the so-called. Newtonian fluids, the main property of which is the ability to move even when a minimum shear stress is applied to them.

By ensuring the pumping of a liquid hydrocarbon mixture in a single-phase state and maintaining its “Newtonian” properties, not only minimal energy losses for its transportation are ensured, but also stable conditions for its pumping.

To do this, when transporting liquid hydrocarbon mixtures, the necessary thermobaric parameters are maintained, and the liquid mixtures themselves, if necessary, are appropriately processed in order to achieve the properties necessary for pipeline transportation.

Viscosity. The choice of pumping technology, energy consumption for transporting liquid hydrocarbons, etc. depend on the viscosity of the transported product. physical properties liquid is a very wide range of its values for different hydrocarbon liquid systems, as well as its strong dependence on transportation temperature. A general property of the viscosity of liquid hydrocarbons is that it decreases with increasing temperature.

In the international system of SI units, dynamic (molecular, shear) viscosity is measured in poise (centipoise, cP) or in mPa. c: the viscosity of liquid hydrocarbons varies over a wide range - from 0.5 to 250 mPa. With.

Pour point- this is the temperature at which the oil (petroleum product) in the test tube does not change its level when the test tube is tilted 45° for 1 minute. The transition of oil from liquid to solid occurs gradually, over a certain temperature range. From the standpoint of physicochemical mechanics of petroleum dispersed systems, the pour point of oil is defined as the transition from a freely dispersed sol to a bound dispersed state (gel).

The temperature of oil (liquid hydrocarbon product) pumped through an underwater pipeline depends (except for the temperature at the entrance to the pipeline) depends on the temperature of the bottom layer of sea water in the case when the pipeline is laid on the seabed without burial, or on the temperature of the soil in the case when the pipeline located in an underwater trench.

The temperature of the pumped liquid determines the viscosity value and its other rheological characteristics and thus affects the pumping mode; it determines the possibility of oil (liquid hydrocarbon product) solidification if its temperature reaches the pour point value.

Since the temperature of the transported product usually decreases as it moves through the pipeline, this can lead to a noticeable increase in its viscosity and coefficient of hydraulic resistance and, as a consequence, to an increase in hydraulic friction losses as long as the temperature of the product drops. Sometimes, this can lead to a complete stop of the pipeline.

If the oil being transported is a waxy or highly waxy (non-Newtonian for transport conditions) environment, such loading fluctuations complicate the operation of pipelines, especially in the case of offshore fields and subsea pipelines. Transport of products with low productivity leads to the formation of stagnant zones and the accumulation of paraffin deposits (sometimes, even when using paraffin deposit inhibitors) with a gradual increase in pressure drop in the pipeline.

The main reason for the formation of paraffin deposits is the temperature factor - its decrease during transportation, and the distribution of paraffin deposits in the pipeline is determined by the characteristics of its thermal regime.

On short offshore pipelines, most often field ones, a technology is sometimes used based on the use of associated heating of the product, which occurs due to heating of the pipe walls.

Gas condensate is a mixture of liquid hydrocarbons condensed from natural gases. Gas condensate is a colorless or slightly colored liquid. Externally, as a rule, gas condensate is a transparent liquid. The color of this liquid can vary from straw yellow to yellow-brown. What does the color of a substance depend on?

It turns out that the intensity of the color of a liquid depends on the amount of oil impurities it contains. You may have heard the name “white oil”. So, this is the generally accepted name for gas condensate.

How is gas condensate separated? Deep in the depths of our earth lie various minerals. Including gas and gas condensate. Having discovered these deposits, the mining company drills a well into the thickness of the earth, trying to get to gas-containing layers. During drilling, the pressure in the formations decreases and at the same time the temperature decreases. As you know, any condensation appears when either the temperature drops significantly environment, or pressure. This is exactly the process that occurs in gas production. The pressure and temperature drop, and at the same time liquid hydrocarbons of mixed composition (C5 and higher) begin to be released from the gas. This is our “white oil”.

Moreover, the higher the barothermal indicators before condensation begins, the greater the amount of hydrocarbons that can be dissolved in the produced gas. The amount of hydrocarbons is also affected by the composition of the gas in the reservoir and the presence of “oil rims”. An oil rim is a part of a reservoir containing oil, as well as gas and condensate. Gas condensate can concentrate in the formation within varying limits - from 5 g/m? up to 1000 g/m?. If gas deposits are located at great depths, then to obtain condensate it is necessary not only to lower the temperature of the gas, but also to additionally absorb and rectify it.

In order for the pressure in the formation to remain at a high level for as long as possible, hydrocarbons of the C1-C2 fraction are pumped back into the well. As a result, so-called “unstable” condensate is obtained directly from the well. It reaches consumers via special conductive systems. Unstable condensate is thoroughly cleaned from impurities and gas is removed from the composition. Now it becomes "stable". This type of gas condensate reaches the end consumer either through pipelines or liquid transport.

What is the composition of gas condensate? The composition of gas condensate is influenced by many factors. The hydrocarbon composition of the condensate and the number of fractions in it are influenced by the formation conditions; conditions under which the selection of a substance occurs. It is very important to take into account the period of time during which a given deposit is exploited. Earlier we mentioned the influence of the “oil rims” present in the reservoir on the composition of the condensate. The conditions for migration of gas condensate into deposits during its formation should also be taken into account, as well as chemical composition reservoir gas. In general, the contents of gas condensate are similar to oil. But, unlike oil, gas condensate does not contain resinous substances and asphaltenes. Basically, it includes gasoline and kerosene components.

Gasoline fractions boil at a temperature of +30 °C - +200 °C, kerosene fractions - within +200 °C - +300 °C. The condensate also contains a small amount of high-boiling components. The yield of gasoline fractions is usually more than half. If the formation is located at great depth, then its composition is dominated by kerosene components and gas oil. More often there are condensates containing methane and naphthenes, less often - containing aromatic or naphthenic hydrocarbons.

What is gas condensate used for? Gas condensate serves as the basis for obtaining fuel or petrochemical products. So from gas condensate or gasoline High Quality. To improve quality, gasoline fractions obtained from condensate are subjected to additional processing. In order to increase the fuel's resistance to detonation, anti-knock agents are added to the composition. Without additional processing, these types of fuel can only be used in the warm season, as they quickly become cloudy and solidify. In order for these types of fuel to work even in cold weather, paraffin is removed from their composition.

For the production of plastics, synthetic rubbers, various types of fibers and resins, aromatic hydrocarbons, olefins and other monomer molecules obtained by processing gas condensate are used. Mining companies are interested in developing condensates available in large fields. They commission installations with a large unit capacity.

For example, the Gazprom company owns fields with gas condensate reserves amounting to more than 1 billion tons. In year this company produces about 13 million tons of gas condensate.
Liquid mixtures of hydrocarbons (all of them differ in different molecular structures and boil at high temperatures), which are released as a by-product in gas condensate, gas and oil fields, are collectively called gas condensates. Their composition and quantity depend on the location and conditions of extraction, and therefore vary widely. However, they can be divided into two types: stable gas condensate in the form of gasoline-kerosene fractions (and sometimes higher molecular weight liquid components of oil), an unstable product, which, in addition to hydrocarbons C5 and higher, includes gaseous hydrocarbons in the form of methane-butane fraction .

Condensate can come from three types of wells where it is produced: Crude oil (it comes in the form of associated gas, which can lie underground separately from crude oil (in layers) or be dissolved in it). Dry natural gas (features a low content of hydrocarbons dissolved in it, condensate yield is low). Wet natural gas (produced from gas condensate fields and has a high content of gasoline condensate). The amount of liquid components in natural gases varies from 0.000010 to 0.000700 m? by 1 m? gas For example, the yield of stable gas condensate at various fields: Vuktylskoye (Komi Republic) - 352.7 g/m?; Urengoyskoe ( Western Siberia) - 264 g/m?; Gazlinskoe (Central Asia) - 17 g/m?; Shebelinskoye (Ukraine) - 12 g/m?.

Natural gas condensate is a multicomponent mixture of various liquid hydrocarbons with low density, in which gaseous components are present. It condenses from the raw gas during the temperature drop during well drilling (below the dew point of the produced hydrocarbons). It is often called simply "condensate" or "gas gasoline". Schemes for separating condensate from natural gas or oil are varied and depend on the field and purpose of the products. As a rule, at a technological installation built next to a gas or gas condensate field, the extracted gas is prepared for transportation: water is separated, purified to a certain extent from sulfur compounds, hydrocarbons C1 and C2 are transported to the consumer, a small fraction of them (of the extracted) is pumped into the formations for maintaining pressure. The separated fraction (after removing C3 components from it, but with a small content of them) is the gas condensate that is sent as a feed stream to oil refineries or petrochemical synthesis plants. Transportation is carried out by pipeline or liquid transport.

Gas condensate at oil refineries is used as a raw material for the production of gasoline with a low octane number, to increase which anti-knock additives are used. In addition, the product is characterized high temperature cloudiness and solidification, so it is used to produce summer fuel. Gas condensate is used less frequently as diesel fuel, since additional dewaxing is required. This direction uses less than a third of the produced condensates.

The most interesting technological solution is the use of a product such as a wide fraction of light hydrocarbons for petrochemical synthesis. With its receipt, the processing of gas condensate begins. Deeper processes continue in pyrolysis plants, where NGLs are used as feedstock to produce important monomers such as ethylene, propylene and many other related products. Then the ethylene is sent to polymerization units, from which various grades of polyethylene are produced. As a result of the polymerization of propylene, polypropylene is obtained. The butylene-butadiene fraction is used to make rubber. Hydrocarbons C6 and higher are the raw material for the production of petrochemical synthesis (benzene is obtained), and only the C5 fraction, which is the raw material for obtaining valuable products, is not yet used effectively.

Gas condensate distillate is an analogue of diesel fuel, close to it in density and other characteristics. It contains gasoline and kerosene fractions, but asphaltenes and resinous substances are absent. Gas condensate distillate is a transparent liquid with a specific odor. It can be light, medium and heavy, differing in composition and scope of application.

We can say that gas condensate distillate, the price of which is relatively low, can be an excellent alternative to diesel fuel. And also, thanks to its decent quality, this product has gained immense popularity in the petrochemical and paint industries. 01/31/18

Gas condensate is a mixture of liquid hydrocarbons,

released from natural gases during the exploitation of gas condensate deposits as a result of a decrease in reservoir pressure and temperature.

Another name for condensate is “white oil”, since condensate is usually transparent or slightly yellow in color due to oil impurities.

Gas condensate serves as the basis for obtaining fuel or petrochemical products. So from gas condensate they get different kinds jet, diesel or boiler fuel or high quality gasoline. To improve quality, gasoline fractions obtained from condensate are subjected to additional processing.

Various minerals lie in the depths of our earth. Including gas and gas condensate. Having discovered these deposits, the mining company drills a well into the thickness of the earth, trying to get to gas-containing layers. During drilling, the pressure in the formations decreases and at the same time the temperature decreases. As you know, any condensation appears when either the ambient temperature or pressure decreases significantly. This is exactly the process that occurs in gas production. The pressure and temperature drop, and at the same time liquid hydrocarbons of mixed composition begin to be released from the gas. This is “white oil”.

4. Properties of natural gases Natural gas is a mineral in a gaseous state. It is used widely as a fuel. But natural gas itself is not used as fuel; its components are separated from it for separate use. Up to 98% of natural gas is methane; it also includes methane homologues - ethane, propane and butane. Sometimes carbon dioxide, hydrogen sulfide and helium may be present. Natural gas is colorless and odorless (if it does not contain hydrogen sulfide), it is lighter than air. Properties of individual components of natural gas Methane is a colorless, odorless gas, lighter than air. Ethane is a colorless, odorless, and colorless gas, slightly heavier than air. Not used as fuel. Propane is a colorless, odorless gas that is poisonous. Butane is similar in properties to propane, but has a higher density. Twice as heavy as air. Carbon dioxide is a colorless, odorless gas with an acidic taste. Unlike other components of natural gas (except helium), carbon dioxide does not burn. Helium is colorless, very light in color and odor. Does not burn. It is not toxic, but at elevated pressure it can cause narcosis, like other inert gases. Hydrogen sulfide is a colorless heavy gas with the smell of rotten eggs. Very poisonous, even at very low concentrations it causes paralysis of the olfactory nerve. Natural gas has several dangerous properties: Toxicity. This is the most dangerous property. It depends on the composition of the gas. For example, methane and ethane in their pure form are not poisonous, but with a lack of oxygen in the air they lead to suffocation. Gases that contain too much carbon monoxide and hydrogen sulfide are also hazardous to health. Explosiveness. All natural gases that contain oxygen form a substance that can easily explode in the presence of a fire source. Each gas has a certain ignition temperature, which depends on its molar mass. Natural gases do not always explode, but only if they contain too much oxygen.