RU2552438C2 - Gas separation method and device for its implementation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: group of inventions relates to gas, gas-processing, chemical, oil industry and can be used in processes and devices for separation of liquid and mechanical impurity from gas flow. The method of separation of gas comprises the supply of mix through a branch pipe of the device at a rate of 10 m/s minimum with the unidirectional transfer of the mix into open volumetric inertial gas-distributing device, supply of liquid drops and mechanical impurity with a part of gas into channels for extraction of liquid and impurity with radial extraction of previously separated gas from the volume inertial gas-distributing device towards the direction opposite to the flow supplied into it with subsequent gas supply to the following separation section. The gas-liquid flow rate is decreased repeatedly. At first the gas-liquid flow is directed from the one-flow input of mix to radial multi-flow with simultaneous separation of liquid with impurity. Then the flow is directed to a rope porous headpiece where it is oscillated, meanwhile the liquid is selected by cords, and then centrifugal separation is performed or centrifugal mass exchange with liquid which is separated simultaneously after that it is separated by means of passing through headpieces with diagonally corrugated surfaces, then through nozzles with diagonally located ledges. The gas separation device comprises the housing with branch pipes for mix input, output of separated phases and separation sections located in the housing and the volumetric inertial gas-distributing device. The volumetric inertial gas-distributing device is designed as a punched wedge-shaped housing with channels for passing of the separated mix with open base and top where the open base of the wedge-shaped housing forms with the mix input branch pipe the passes for recirculation gases, and the open top of the wedge-shaped housing is fixed in the drainage channel. The following is series installed between branch pipes of the gas-liquid mix inlet and the drained gas outlet - the volumetric inertial gas-distributing device, the rope porous headpiece fixed rigidly on the ends of the volume inertial gas-distributing device, the dish-shaped section of centrifugal separation or mass exchange with simultaneous separation, diagonally corrugated headpiece sections and/or sections made of sheets with fine-structured ledges with effective cross-sections for passing of gas-liquid flow widened from the first section to the last section.

EFFECT: creation of effective method and device for gas separation without filtering coalescing cartridges with self-cleaning of the preliminary separation system.

5 cl, 4 dwg

Description

The group of inventions relates to the gas, gas processing, chemical, and petroleum industries and can be used in processes and apparatuses for separating liquids and solids from a gas stream, for example, in schemes for preparing gas for transport, at field facilities during a period of falling reservoir pressure, and connecting booster pumps compressor stations (BCS), in the schemes of extraction from underground gas storages (UGS).

A known method and device for gas separation according to the monograph of A.I. Gritsenko, V.A. Istomin, A.N. Kulkov, R.S. Suleymanov “Collection and field preparation of gas in the northern fields of Russia”, Moscow OJSC Nedra Publishing House 1999 (p. 341-345, fig. 7.21., 7.22.), P. 474, according to which the raw gas is supplied to booster compressor stations they are fed sequentially to primary or dust separators, where coarse separation of formation fluid (water with impurities of salts and hydrocarbon condensate) and mechanical impurities is performed, after which gas is fed to filter separators for fine gas purification from fine liquid droplets and solid parts to avoid salt deposits on the blades of the supercharger-compressor pumping unit GPA-C-16-55 and avoid their erosion.

The disadvantages of this separation method are:

- the presence of two stages of separation - the primary and the stage of gas filtration, which requires increased building areas, an increase in the length of the piping, additional fittings and control and automation devices;

- the presence of a filtration stage prone to clogging, for the continuous operation of the installation requires the use of a backup filtration stage - backup devices, which increases capital and operating costs;

- the increased and changing from the operating time the hydraulic resistance of the filter stage increases the energy costs of gas compression;

- insufficient separation efficiency requires the use of washing devices or sections to reduce the salt content.

Known devices:

- the primary separator includes centrifugal separation sections and a separation section on a porous volumetric structure, for example, mesh conical drums, Fig. 7.21., 7.22. the specified analogue;

- the filter separator includes a filter coalescence section based on filter coalescing cartridges mounted on a grate for separating mechanical particles and coalescing (enlarging) finely divided liquid droplets, and the subsequent separation stage of coarse fine droplets, based on direct-flow centrifugal elements or mesh chippers , fig. 7.21., 7.22. specified analogue.

The disadvantages of these separation devices are:

- the presence of two devices of the primary separator and filter separator;

- the presence in the filter separator of filter-coalescing cartridges, which require frequent replacement. For continuous operation of the separation system, they require the use of backup devices and the use of quick-opening shutters on them, and this increases the cost of equipment and operating costs;

- the increased and changing from the operating time the hydraulic resistance of the filter separator increases energy costs and reduces the efficiency of separation as the filter-coalescing cartridges become dirty;

- insufficient separation efficiency, in turn, requires the use of washing devices or washing sections to reduce the salt content.

Known devices for gas separation using separation and filtration equipment [see CATALOG Technological equipment and installations for the extraction, transportation, processing and underground storage of natural and associated petroleum gases, hydrocarbon condensate and oil. Moscow 1996, (IRC Gazprom), pp. (22–37)], using inlet mesh gas separators or gas separators with centrifugal elements and filter separators installed behind these devices in front of compressors.

The main disadvantages of these devices:

- the presence of two sequentially installed apparatus of the primary separator and filter separator, which requires additional building areas, increasing the length of the piping, requires additional fittings, control devices and automation;

- the presence of filter separators, prone to clogging, for the continuous operation of the installation requires the use of backup devices, which increases capital and operating costs;

- the increased and changing from the operating time the hydraulic resistance of the filter separator increases the energy costs of gas compression and reduces the separation efficiency;

- insufficient separation efficiency requires the use of flushing apparatuses or flushing sections to reduce the salt content, especially during the period of falling reservoir pressure;

- the presence in the filter separator of filter-coalescing cartridges, which require frequent replacement, requires the installation of backup devices and the use of quick-opening shutters for continuous operation, which increases capital and operating costs.

Primary separators are known in which the disadvantages of their low efficiency are partially eliminated due to the use of a washing section in them, i.e. sections for washing the gas with water, in which the gas after centrifugal separation is directed to contact with the washing liquid - water without salts and impurities, i.e. to the mass transfer section with plates on the basis of direct-flow centrifugal mass transfer elements installed between the centrifugal separation sections and the final separation sections [see Materials of the Scientific and Technical Council of RAO Gazprom, pp. (145 ÷ 146), Moscow 1997, (IRC Gazprom)].

There is a known method of gas separation and apparatus for its implementation according to the patent of the Russian Federation No. 2385756, IPC B01D 45/04 (2006/01) - a prototype comprising a direct-flow supply of raw gas (gas-liquid mixture) directly into the inertial gas distribution device at an angle (7 ÷ 10) degrees to its side wall, which allows particles of mechanical impurities and liquid droplets having a significant mass, in comparison with gas, to direct due to inertia forces to the impurity extraction channel, and the gas flow through the perforation (louvres directed channels) to the side wall inertial volumetric Timing device. After the initial inertial separation and gas distribution into many multidirectional flows, they enter the next gas separation stage with a liquid content of about 20% or less of the initial content in the raw gas.

The direct-flow supply of a gas-liquid mixture directly to the inertial volumetric gas distribution device at the level of the mixture supply reduces the height of the apparatus body and releases the body volume for installation of additional sections. The implementation of a volumetric inertial gas distribution device in the form of an open perforated casing with the mixture inlet nozzle along its axis not only increases the separation efficiency, but also provides access to internal devices and the walls of the apparatus without installing additional manholes.

The disadvantages of this method and device are:

- the need to use after them a second separation stage - an additional filter separation stage for enlarging finely dispersed liquid particles and filtering gas from mechanical impurities, which has a limited service life and requires periodic replacement of filter-coalescing cartridges with apparatus stopping and has a significant and time-varying operation hydraulic resistance and increased operating costs and requiring significant capital costs;

- pre-separation systems for gas-liquid flow require periodic cleaning.

The technical result of the group of inventions is to create an effective method and device for gas separation without the use of filter-coalescing cartridges (elements) with self-cleaning of the preliminary separation system.

A single technical result when implementing a group of inventions on an object - the method is achieved by the fact that in a gas separation method comprising supplying a mixture through an apparatus nozzle at a speed greater than or equal to 10 m / s with unidirectional transfer of the mixture into an open volumetric inertial gas distribution device, the direction of liquid droplets and mechanical impurities with a part of the gas in the channels for the selection of liquids and impurities with fan selection of pre-separated gas from the inertial gas distribution unit devices in the direction oriented backward to the flow of the stream supplied to it, followed by gas supply to the next separation section, while the gas-liquid flow rate is reduced many times: first, it is directed from a single-flow inlet of the mixture to a multi-flow fan with simultaneous separation of the liquid with impurities, then sent to a tow a porous nozzle, where it is oscillated, while the liquid is taken along bundles, and then centrifugal separation or centrifugal mass transfer with the liquid is carried out, which they are simultaneously separated, then separated by passing through nozzles with oblique surfaces, then onto nozzles with oblique protrusions.

The minimum working speed of the outlet gas stream to the cross section of the apparatus W in m / s is determined from the values of the gas velocity factor by the formula

where ρ is the gas density under operating conditions, kg / m ³ . A single technical result in the implementation of the group of inventions on the object - the device is achieved by the fact that in the device for gas separation, comprising a housing with nozzles for the inlet of the mixture, the output of the separated phases and the separation sections located inside the housing and a volumetric inertial gas distribution device made in the form of a perforated wedge-shaped housing with channels for passage of the separated mixture with an open base and a top, in which the open base of the wedge-shaped body forms with an inlet pipe with Mesi passages for recirculation gases, and the open top of the wedge-shaped body is fixed in the drainage channel, sequentially installed between the nozzles of the inlet of the gas-liquid mixture and the outlet of the dried gas:

- volume inertial gas distribution device;

- a porous tourniquet fixed rigidly at the ends of a volumetric inertial gas distribution device;

- centrifugal separation or mass transfer section with simultaneous plate-type separation;

- nozzle sections oblique and (or) from sheets with finely structured protrusions, made with live sections for the passage of gas-liquid flow, increasing from the first section to the last section.

The inertial gas distribution device is made with an inlet live section within (13–15)% higher than the live section of the inlet pipe.

The maximum live section at the exit of the packed sections is equal to (85 ÷ 98)% of the cross section of the apparatus body.

The decrease in the gas-liquid flow rate is manifold: first, it is directed from a single-flow inlet of the mixture to a multi-flow fan with simultaneous separation of liquid with impurities, then it is sent to a porous tourniquet to collect liquid from bundles, ensuring its oscillation, followed by centrifugal separation or centrifugal mass transfer with liquid its simultaneous separation, and then by separation, passing through nozzles with oblique surfaces, and then onto nozzles with oblique nnym protrusions possible to increase the efficiency of gas separation method without using a filtration process.

The choice of the velocity of the inlet stream of the gas mixture in the nozzle greater than or equal to 10 m / s made it possible, due to the increased inertia forces, to more effectively separate liquid particles and mechanical impurities.

Determination of the minimum working speed of the outlet gas stream W in m / s from the values of the gas velocity factor by the formula

where ρ is the gas density under operating conditions kg / m ³ ,

allowed to determine the range of effective operation of the method and apparatus.

The establishment between the nozzles of the inlet of the gas-liquid mixture and the outlet of the dried gas in series volume inertial gas distribution device; a porous tourniquet fixed rigidly at the ends; centrifugal separation or mass transfer sections with simultaneous plate-type separation; nozzle sections oblique and (or) from sheets with finely structured protrusions and their execution with live sections for the passage of gas-liquid flow, increasing from the first section to the last, made it possible to implement the inventive method of gas separation and achieve a single technical result.

The implementation of a volumetric inertial gas distribution device with a live section at the inlet, in the interval (13 ÷ 15)% higher than the live section of the inlet pipe, made it possible to obtain an efficiency of this device of at least 80%.

The maximum living section at the exit of the packed sections equal to (85 ÷ 98)% of the cross section of the apparatus body allowed to reduce the entrainment of liquid with gas to 5 mg / m ³ gas or less.

The authors are not aware of gas separation methods and devices for their implementation, in which an increase in gas separation efficiency would be achieved in a similar way.

In FIG. 1 is a diagram illustrating a gas separation method.

In FIG. 2 shows a device for implementing a gas separation method.

In FIG. 3 is a section along AA of FIG. 2.

In FIG. 4 is a section BB of FIG. 2.

Object — a method for separating liquid and solids from a gas stream is carried out according to the scheme shown in FIG. 1, consisting of the following technological sections:

I - section for collecting the separated liquid and impurities;

II - section of inertial separation and gas distribution;

III - section of coalescence and dynamic separation;

IV - section of centrifugal separation or mass transfer of gas with liquid and simultaneous separation of gas from the contacted liquid;

V - separation section on oblique surfaces;

VI - separation section on surfaces with oblique porous protrusions.

The gas-liquid flow G ₀ with mechanical impurities of a certain speed (Fig. 1) is sent to the inertial separation and gas distribution section II, where it is divided into partially purified gas flows g ₀ , and the liquid and particles of mechanical impurities with a specific gravity of more than the specific gravity of the gas due to the inertia forces in the direct flow with a part of the gas are directed by a stream L ₁ to the section I for collecting liquid and mechanical impurities. The use of an inertial separation system eliminates clogging, i.e. excludes the process of cleaning it.

The main gas stream in the inertial separation and gas distribution sections, divided into many streams g ₀ , fan-shaped is turned in the direction oriented in the opposite direction of the incoming gas-liquid stream, and thereby reduce its speed. Part of the gas stream g _p with drops of liquid is fed back to inertial separation and gas distribution (for recirculation). Then, the gas flow rate g _{0 is} reduced in the section of coalescence and dynamic separation III, in which fine droplets of liquid are coarsened and shaken with mechanical impurities in section I of the collection of liquid and mechanical impurities. The selection of fluid occurs under the influence of gravity, during vibration (oscillation) of the tows by the oncoming gas stream. This allows self-cleaning of the coalescence section and dynamic separation III. Then, to further reduce the speed, the purified gas flows g _{1 are} directed to the centrifugal separation section or the centrifugal mass transfer section with the liquid and the gas is simultaneously separated from the contacted liquid IV, on which, for example, gas is washed with drops of liquid from soluble salts or methanol is blown out of its aqueous solution.

After the centrifugal separation section or centrifugal mass transfer with separation, the gas is supplied by g ₂ streams for separation to the nozzle section with oblique surfaces V, in which the gas flow rate is again reduced by increasing the living cross section for gas passage compared to the centrifugal separation section, after which the gas minor impurities (traces) of the fluid flows g ₃ served on the separation section on surfaces with oblique porous protrusions or oblique surfaces VI, where they carry out approx final separation. Further, the purified gas G is supplied to the compressor units or to the consumer.

Liquid from the section of inertial separation and gas distribution II, coalescence and dynamic separation on a porous bundle nozzle III, centrifugal separation or mass transfer of gas with liquid while simultaneously separating gas from the contacted liquid L ₀ IV, separation on oblique surfaces V, separation on surfaces with oblique porous protrusions VI flows: L _1, L ₂ , L ₃ , L ₄ , L ₅ respectively served in the section for collecting the separated liquid and impurities I, from where it is removed by stream L.

An example implementation of the method.

Gas consumption, nm ³ / h - 450,000;

Fluid flow rate per gas unit, g / nm ³ - (1.5 ÷ 0.9) without supply of flushing fluid;

Flushing fluid consumption, kg / h - 80;

Gas pressure, MPa - (2.0 ÷ 2.4);

Gas temperature, ° C - (8.6 ÷ 15);

Pressure drop, kPa - (1.9 ÷ 2.7);

The liquid content in the separated gas, mg / nm ³ - (0.6 ÷ 3.4);

The gas velocity factor in the apparatus body, m / s · kg / m ³ ) ^0.5 - 5.

The object device is a gas separator for implementing the method of separation of liquid and impurities from the gas stream (Fig. 2) contains:

- building 1;

- the inlet pipe of the gas-liquid mixture 2;

- outlet pipe of the purified gas 3;

- a pipe for supplying liquid for mass transfer with gas 4;

- outlet pipe of the separated liquid and impurities 5;

- volumetric inertial gas distribution device 6 (Fig. 3), which is made in the form of a perforated wedge-shaped housing 7 with louvered channels 8 for passage of the separated mixture with an open base 9 (Fig. 3, 4) and apex 10 (Fig. 3), and open the base 9 of the wedge-shaped body 7 forms with the inlet of the mixture of 2 passages for recirculation gases 11 (Fig. 3, 4), the open top 10 of the wedge-shaped body 7 is fixed in the drainage channel 12 (Fig. 2, 3);

- nozzle 13, made in the form of a vertically oriented microstructure (Fig. 3), stretched against the louvered channels 8;

- direct-flow centrifugal plate 14 (Fig. 2) is installed in the housing 1 above the volumetric inertial gas distribution device 6. When the fluid supply through the pipe 4 is turned off, the direct-flow centrifugal plate 14 acts as a separation stage, and when the liquid is supplied through the pipe 4, it plays the role of a mass transfer stage with simultaneous separation from the droplets of the supplied liquid;

- nozzles 15 are made of oblique surfaces and mounted above a direct-flow centrifugal plate 14;

- nozzles 16 made of sheets with oblique finely structured protrusions or of oblique surfaces;

- overflow (s) 17.

The device operates as follows.

The main gas stream is supplied through the pipe 2 to the gas separator 1 body (Fig. 2, 3) to the inertial gas distribution device 6 through its open base 9 (Fig. 3) into the perforated wedge-shaped housing 7 with louver channels 8 for passage of the separated mixture into wherein a gas stream dividing into a plurality of streams g ₀ (Fig. 1) and fan-shaped in a direction oriented in the opposite direction of the gas-liquid flow decreases the speed. The open base 9 of the wedge-shaped housing 7 (Fig. 4) forms with the inlet of the mixture inlet 2 passages 11 for recirculation of gas flows. Through the open top 10 (Fig. 3) of the wedge-shaped body 7, mounted in the drainage channel 12, drain the liquid and mechanical impurities. Then, the gas flows g ₀ (Fig. 1) are fed to the nozzle 13 (Fig. 3), on which fine droplets of liquid are coarsened and shaken with mechanical impurities into the section for collecting liquid and mechanical impurities located in the lower part of the housing 1 (Fig. 2) , and are discharged through the outlet pipe of the separated liquid and impurities 5. The selection of liquid occurs under the action of gravity due to the oscillation of the nozzle 13, which occurs from the transverse forces of the gas incident on them. This allows self-cleaning nozzles 13. The nozzle 13, made in the form of a vertically oriented microstructure with an enlarged living section for the passage of the gas-liquid mixture compared with the living section of the blinds 8, reduces the gas flow rate. To further increase the living cross section for the passage of the partially purified gas-liquid mixture and to further reduce the flow rate g ₁ (Fig. 1), the partially purified gas is sent to a direct-flow centrifugal plate 14 (Fig. 2) with a live cross section larger than the live cross section of the nozzle 13. When turning off the liquid supply through the pipe 4 (Fig. 2) to the direct-flow centrifugal plate 14, it acts as a separation stage, and when the liquid is supplied through the pipe 4 (Fig. 2), it plays the role of a mass transfer stage with simultaneous separation of the supplied liquid from drops dkosti, which produce, for example, washing the gas with droplets of liquid from the soluble salts or stripping of methanol from its aqueous solution.

A further increase in the living cross section for the passage of a partially purified gas stream and reducing its speed occurs on nozzles 15 made of oblique surfaces, and then on nozzles 16 installed above them, made of sheets with oblique finely structured protrusions or from oblique surfaces, the live section of which is ( 85 ÷ 98)% of the cross section of the apparatus. On nozzles 16 of the final gas separation section, on which gas with minor impurities (traces) of liquid is directed by g ₃ flows (Fig. 1), the final separation is carried out. Then the purified gas through the outlet pipe of the purified gas 3 (Fig. 2) is discharged from the separator body 1 and is supplied to the compressor units or to the consumer. The liquid from nozzles 15 and 16 is fed to a plate with centrifugal straight-through elements 14, from where it is discharged through overflow (s) 17 (Fig. 2), and then from the lower part of the separator body 1 through the outlet pipe of the separated liquid and impurities 5.

Thus, a decrease in the velocity of the gas-liquid flow during its purification in the gas separator is achieved by a gradual increase in the living cross section for the passage of the gas-liquid mixture in each element installed in the gas separator body from the inlet to the outlet, while a single technical result is achieved, which consists in creating an effective method and gas separation devices, without the use of filter elements.

Claims (5)

1. The method of gas separation, including feeding the mixture through the nozzle of the device with a speed greater than or equal to 10 m / s with unidirectional transfer of the mixture into an open volumetric inertial gas distribution device, the direction of liquid droplets and mechanical impurities with part of the gas into the channels for the selection of liquids and impurities with a fan selection of pre-separated gas from the inertial gas distribution device in the direction oriented back to the flow of the feed supplied to it, followed by the supply of ha and to the next separation section, characterized in that the gas-liquid flow rate is reduced many times: first, it is directed from a single-flow inlet of the mixture to a multi-flow fan with simultaneous separation of the liquid with impurities, then it is sent to a porous tourniquet, where it is oscillated, and the liquid is sampled bundles, and then carry out centrifugal separation or centrifugal mass transfer with the liquid, which is simultaneously separated, then separated by passing through the nozzles from the braids with pressed surfaces, then onto nozzles with oblique protrusions. 2. The method of gas separation according to claim 1, characterized in that the minimum working speed of the outlet gas stream W in m / s is determined from the values of the gas velocity factor by the formula:
Ф = W · ρ ^0.5 = (4.0 ÷ 6.0),
where ρ is the gas density under operating conditions, kg / m ³ . 3. A device for gas separation, comprising a housing with nozzles for the inlet of the mixture, the output of the separated phases and the separation sections located inside the housing and a volumetric inertial gas distribution device made in the form of a perforated wedge-shaped housing with channels for passage of the separated mixture with an open base and apex, in which an open the base of the wedge-shaped body forms passages for recirculation gases with the inlet of the mixture of the mixture, and the open top of the wedge-shaped body is fixed in the drainage channel, about characterized in that the inertial gas distribution device, the porous tow nozzle fixed rigidly at the ends of the inertial gas distribution device, the centrifugal separation or mass transfer section with the simultaneous plate-shaped separation, the nozzle / slanted sections of sheets with finely structured protrusions made with live sections for the passage of gas-liquid sweat ka, increasing from the first section to the last section. 4. A device for gas separation according to claim 3, characterized in that the inertial gas distribution device is made with an inlet live section within (13 ÷ 15)% greater than the live section of the inlet pipe. 5. A device for gas separation according to claim 3, characterized in that the maximum live section at the outlet of the packed sections is equal to (85 ÷ 98)% of the cross section of the apparatus body.

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