RU2344869C2 - Method of liquid separation from gas flow and device for its realisation - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: method of liquid separation from gas flow includes swirling of gas-liquid flow, formation of rotating liquid layer on surfaces of cylindrical nozzle and axial revolution body, separation of flows into liquid and gas phases. Thickness of liquid layer is increased on maximum radius of peripheral edge of axial revolution body provided with inclined teeth, and discrete enlarged liquid drops are shaped by exposure of liquid layers to swirled gas flow. Device for separation comprises face of plate with direct-flow-centrifugal elements, every of which comprises cylindrical nozzle with swirler at the inlet and separation device in the form of cap film stripper at the outlet, annular partition between external wall of nozzle and internal wall of film stripper, displacer installed inside cylindrical nozzle, recirculation channel. Displacer is equipped with inclined teeth provided on its peripheral edge. Incline of teeth is oriented to the side of gas flow swirling. Annular partition is arranged with oppositely installed channels for bleeding of liquid and gas phases.

EFFECT: higher efficiency of separation at changing loads by gas and liquid and expansion of application field.

7 cl, 6 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 liquid from a gas stream after it is in contact with a liquid, for separating a gas-liquid stream, for absorbing moisture by liquid absorbers, and for drying natural and oil gas.

The known method and device for separating gas-liquid flow into gas and liquid phases in the field of centrifugal forces when twisting the gas flow to patent No. 1072865 of the Russian Federation, IPC 4: B01D 3/26. By the specified known method produce:

- twisting the main gas stream;

- separation of the gas-liquid flow in the field of centrifugal forces with the formation of a liquid film on the inner wall of the pipe;

- subsequent removal of the film with a portion of the gas through the gap between the cylindrical pipe and the cap film stripper.

The device includes a direct-flow centrifugal element consisting of a cylindrical nozzle, a swirl at the inlet, a film stripper at the outlet, and a fluid supply device in the form of a flanged vertical wall inside the nozzle.

The disadvantage of this method and device is the inefficient separation of liquid droplets from the axial zone of the element, i.e. at small radii, due to small centrifugal forces.

The known method and device according to patent No. 1149475, IPC 6: B01D 3/26, in which the above disadvantages are eliminated by supplying liquid along the axis of the swirling gas stream to the surface of the body of revolution (displacer), which allows you to transfer liquid drops from the zero radius of the axis of the element to the initial radius equal to the radius of the displacer edge. This increases the separation efficiency of the gas-liquid flow by increasing the centrifugal force acting on the liquid drop in the axial zone of the element.

The device includes a base with direct-flow centrifugal elements, each of which consists of a cylindrical nozzle with a swirl at the inlet, a cap film stripper at the outlet, a displacer made in the form of a rotation paraboloid mounted on the tube wall along the nozzle axis.

The disadvantages of the method and device are:

- reduced efficiency of the separation of the gas-liquid mixture due to repeated crushing of the liquid on the walls of the tube;

- uneven diameter of the drops falling from the displacer;

- the need for the location of the edges of the displacer strictly in a horizontal plane along the axis of the nozzle.

The closest method of the same purpose to the claimed method in the group of inventions according to the totality of features is “Method of gas and liquid contact and a device for its implementation” - patent No. 2192912, IPC 7 B01D 3/26 (prototype method), which includes twisting the gas stream, supplying liquid to the low pressure zone, dispersing and forming it into a film on the surface of the body of revolution, separation of the gas-liquid flow into liquid and gas phases upon preliminary contact of the gas with a cylindrical rotating liquid layer.

The device includes a base with direct-flow centrifugal elements, each of which consists of a cylindrical nozzle equipped with a separation device in the upper part and a tangential swirl, a diaphragm annular partition, and a flow recirculation tube in the lower part.

The disadvantage of this method and device is the low separation efficiency of liquid droplets of various diameters that break down along the entire perimeter of the displacer, the deterioration of the separation efficiency with increased fluid loads.

Known direct-flow centrifugal separation element according to the patent of the Russian Federation No. 1409312, IPC: B01D 45/12, containing a vertical cylindrical nozzle placed on the plate, swirl at the inlet and cap film stripper at the outlet of the cylindrical nozzle, a transverse support wall between the nozzles and the film stripper with segment cuts along the outer diameter for the selection of gas-liquid mixture.

The disadvantage of this device is the secondary entrainment of fluid at the outlet of the cap film strip along the moving gas stream when dumping it on the base - the plate of the plate. A gas with a lower density escapes from the scraper along a smaller radius up, a liquid with a higher density moves down a larger radius, that is, the separated phases intersect. When the phases intersect, secondary entrainment of the liquid by a gas stream occurs.

The closest device of the same purpose to the claimed device in the group of inventions for the totality of features is "Direct-flow centrifugal separation element" - patent No. 2094073, IPC: B01D 3/26; B01D 45/12 (prototype device). The direct-flow centrifugal element includes a cylindrical nozzle with a swirl in the lower part and a film stripper in the upper part, an annular support partition made of two sectors placed one above the other, one of which is mounted on the outer surface of the nozzle, and the other with axial rotation.

The specified technical solution allows the selection of liquid along the inner radius of the dropper (a large radius), and the selection of the gas phase along the outer diameter of the nozzle, which reduces the repeated entrainment of the fluid by the associated gas stream coming out from under the dropper.

The disadvantage of this device is the exit of the gas-liquid stream from one channel — the annular sector, on the one hand, which leads to the re-crushing of the liquid by the gas stream coming out from under the dropper and the deterioration of the separation efficiency.

The problem to which the claimed group of inventions is directed is to create an effective method and device for separating liquid from a gas stream under varying loads of gas and liquid.

A single technical result in the implementation of the group of inventions in terms of the object method is achieved by the fact that in the method of separating liquid from a gas stream, including swirling a gas-liquid stream, forming a rotating liquid layer on the surfaces of the axial and peripheral bodies of revolution, separating the flows into liquid and gas phases and their subsequent selection, at the maximum radii of the rotating fluid layers formed on the axial and (or) peripheral bodies of revolution by exposing these layers to a swirling gas stream, Braz discrete enlarged liquid droplets.

The selection of liquid and gas is carried out separately, and the selection of the liquid phase is carried out at the maximum radius, and the gas phase at the minimum radius.

The rotating fluid layer on the surface of the peripheral body of revolution is formed by the diaphragm of a swirling gas-liquid flow, while part of the liquid is sampled immediately before its diaphragm and the gas-liquid mixture is recycled after the diaphragm.

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 separating liquid from the gas stream, including the plate plate with direct-flow centrifugal elements, each of which consists of a cylindrical nozzle with a swirl at the inlet and a separation device in the form of a cap a film stripper at the exit, an annular support partition and a displacer inside a cylindrical pipe, a recirculation channel, a displacer and (or) a cylindrical pipe are provided on inclined teeth located on their peripheral edge, and the inclination of the teeth is oriented towards the swirl of the gas stream.

An annular diaphragm partition is located on the inner wall of the nozzle above the plate plate, directly above and below which are channels for supplying a gas-liquid mixture and for taking liquid.

Between the inner wall of the cap dropper and the outer wall of the cylindrical nozzle there is a support ring U-shaped partition with oppositely arranged channels for sampling the liquid and gas phases, and the channels for sampling the liquid phase are made at the maximum radius, and for the selection of the gas phase at the minimum radius.

The cylindrical nozzle is made of a diamond-shaped sheet, when the sides are connected, a spiral joint is formed, oriented in the direction of gas-liquid flow, and the recirculation channel is made in the form of holes or a recirculation tube with central walls flanged upwards, on which the displacer is fixed.

The separation of the liquid from the gas stream by enlarging the liquid droplets to a narrow range of the same size, and the implementation of the device, the design of which made it possible to enlarge the liquid droplets, made it possible to create an effective method and device for separating liquid from a swirling gas stream under varying gas and liquid loads.

The authors are not aware of methods for separating liquid from a gas stream and devices for its implementation, in which an increase in the efficiency of liquid separation under varying loads of gas and liquid would be achieved in a similar way.

Figure 1 presents a diagram illustrating the proposed method for separating liquid from a gas stream.

Figure 2 presents a device for implementing a method of separating a liquid from a gas stream.

Figure 3, 4, 5 shows a cross section: aa, bb, bb of Fig.2.

Figure 6 presents a device for implementing the method of separating liquid from a gas stream with a recirculation tube.

Object - a method of separating liquid from a gas stream is as follows. The gas-liquid flow G ₀ (FIG. 1) is divided into a plurality of gas flows q ₀ and liquids L ₀ , which are twisted, forming a plurality of tangentially directed gas and liquid jets (FIGS. 1, 5). A cylindrical rotating layer L is formed from the liquid by tangentially directed gas jets. Then a cylindrical rotating layer of liquid L is diaphragmed, and a part of the liquid (stream L ₁ ) is selected from the cylindrical rotating layer of liquid L immediately before its diaphragm. After diaphragm from the liquid droplets, rotating fluid layers L ₂ and L _{3 are formed} on the surfaces of the axial and peripheral bodies of revolution (on the surface of the displacer and the inner surface of the cylindrical pipe), respectively. At the maximum radius of the rotating liquid layer L ₂ formed on the surface of the axial body of revolution, discrete enlarged droplets of liquid L _{are formed} by transferring it by a gas stream q. These discrete enlarged drops of liquid L _in the gas stream q are transferred to a rotating liquid layer L ₃ formed on the peripheral body of revolution (inner surface of the cylindrical pipe).

In the separation zone at the maximum radius of the rotating fluid layer L ₃ formed on the peripheral body of revolution, discrete enlarged fluid drops L _p can also be formed by acting on this layer with a swirling gas stream q.

Coarse liquid droplets L _p are transferred by a swirling gas stream q ₁ into the separation zone and precipitated as a liquid layer on its surface (inner surface of the cap dropper), from where it is taken (stream L ₄ ) at the maximum radius. Gas (stream G ₁ ) is taken at a minimum radius, while the selection of gas and liquid is carried out in oppositely located channels.

The main swirling gas stream G is taken from the axial separation zone.

The gas stream G ₁ selected from the separation zone is divided into two flows G ₂ and G _p . The stream G _{2 is} connected to the main swirling gas stream G, selected from the axial separation zone. And the gas stream G _p and part of the liquid L _{p of the} stream L ₄ taken from the separation zone is sent for recirculation as a gas-liquid mixture G _p L _p to the zone after diaphragm. The remaining main fluid stream L _{t is} fed onto the plate web, from where it is diverted.

Example.

The maximum gas consumption, kg / h - 64447

Gas pressure, MPa - 12.48

Temperature, gas, ° С - 29

The volumetric flow rate of liquid, m ³ / s - 0,0072

The diameter of the direct-flow centrifugal element, m - 0.1

Displacer diameter, m - 0.05

Discrete surface area, m ² - (0.001 · 0.001) = 1 · 10 ^-6

The number of discrete surfaces (teeth), pcs. - 24

The increase in droplet diameter on discrete surfaces, times

(0.05 · 3.14 · 0.001 / 24 · 1 · 10 ^-6 ) = 6.5

Working speed in a direct-flow centrifugal element, m / s - 0.6

Fluid entrainment with gas, g / 1000 nm ³ ≈12

The object is a device for implementing the method of separating liquid from a gas stream (Fig. 2) contains direct-flow centrifugal elements 1 mounted on a plate of plate 2, each element consists of a cylindrical pipe 3, at the inlet of which a swirler 4 with louvred channels 5 is installed (Fig. 2, 5), and at the output a separation device made in the form of a cap dropper 6, and inside the cylindrical pipe 3 there is an annular diaphragm septum 7 and a displacer 8 equipped with pointed oblique teeth 9 (Fig. 2, 3). Over the annular diaphragm septum 7, which is located above the plate 2, there is a recirculation channel 10 for supplying a gas-liquid mixture, and below it a channel for liquid selection 11. The upper part of the cylindrical pipe 3 can be equipped with pointed inclined teeth 12 (Fig.2, 3) . Between the outer wall of the cylindrical pipe 3 and the inner wall of the cap dropper 6, a support U-shaped partition 13 is installed, on which there is a larger radius for the fluid sampling channel 14 (Figs. 2, 4) and a small radius for the gas sampling ducts 15 (Fig. 2, four). The channel for the selection of liquid 14 and channels for the selection of gas 15 are made opposite.

The cylindrical pipe 3 is made of a sheet in the form of a parallelogram. When connecting the sides of the sheet, a spiral joint 16 is formed with an inclination angle of ≈45 °, oriented in the direction of gas-liquid flow movement.

At low fluid loads, the fluid withdrawal channel 11 is absent, and the recirculation channel 10 is in the form of a tube 17 with walls 18 flanged upwards in the center and on which a displacer 8 is fixed along the pipe axis (Fig. 6).

The device operates as follows.

The gas-liquid flow G ₀ (Fig. 1) is fed to the direct-flow centrifugal element 1 through the louvre channels 5 of the swirler 4 (Figs. 2, 5), on which it is divided into many gas flows q ₀ and liquid L ₀ and twisted (Fig. 1 , 5). The liquid layer L on the inner surface of the cylindrical pipe 3 is set by the inner diameter of the annular diaphragm septum 7. With large mass ratios of the liquid to gas (more than 0.02), the liquid (stream L ₁ ) is taken from the inner surface of the cylindrical pipe 3 through channels 11 onto the plate 2 from where they take it away.

When using a direct-flow centrifugal element 1 as mass transfer channels 11 are not executed or are drowned out, and channels 10 are supplied with liquid from the plate 2 to contact with gas flows q ₀ (Figs. 1, 5).

After the diaphragm, the liquid under the action of centrifugal forces serves on the surface of the bodies of revolution: the inner surface of the cylindrical pipe 3 (figure 2), forming a layer of liquid L _{3 on it} (figure 1), and the surface of the displacer 8 (figure 2), forming on it a layer of liquid L ₂ (figure 1).

A layer of liquid L ₂ from the surface of the displacer 8 is transferred to swirling gas flows q on the surface of the teeth 9, thereby increasing its thickness. Then, on the tips of evenly spaced inclined teeth 9, the surface of which is minimal, coarse drops of liquid L _{in are formed} (Fig. 1). Coarse droplets L _in from the tips of the teeth 9 with a gas stream q are transferred to the inner surface of the cylindrical nozzle 3 into a layer of liquid L ₃ , which is then transferred to the surface of the teeth 12 (if any) in the upper part of the cylindrical nozzle 3. On the tips of the teeth 12, coarsened liquid droplets L _p. Formed liquid droplets L _p are transferred by a gas stream G ₁ to the inner surface of the cap dropper 6, forming a layer of liquid L _{4 on it} . The gas separated from the liquid is taken off by a swirling flow G in the center of the cap dropper 6. The separated liquid from under the cap dropper 6 is taken off through the liquid withdrawal channel 14 (stream L ₄ ), and the gas (stream G ₁ ) through the gas withdrawal channels 15. From the selected gas (stream G ₁ ), a part of the gas is separated (stream G _p ) and sent for recirculation to the channel 10. To increase the separation efficiency, the gas-liquid mixture (stream G _p , L ₄ ) formed from the separated liquid stream L ₄ and the gas stream is recycled G _p, from mezhpat ubkovogo space via channels 10 which are located above the diaphragmed walls 7. The remaining part of gas (stream G ₂₎ 1 connected to a separated liquid from the gas (stream G).

If there is one recirculation channel 10 (without channel 11) (Fig. 6), recirculation flows L _p and G _p are fed through channel 10 of the tube 17 to the surface of the displacer 7.

The use of the proposed method and device for separating liquid from a gas stream made it possible to ensure effective separation of liquid from a swirling gas stream, including under varying gas and liquid loads. An increase in the separation efficiency was achieved by increasing the diameter of the separated droplets in a centrifugal field, bringing the droplets to a uniform diameter and their uniform distribution on the perimeter of rotation bodies with a maximum radius. By diaphragming the liquid flow above the plate web, an extended range of effective operation of the separation device is achieved. The scope of the device, which can be used as mass transfer and separation, has been expanded. The implementation of the teeth on the upper part of the nozzle allows the dropper to fit on the nozzle with the transfer of fluid directly to the inner wall of the dropper without crushing the liquid by the gas stream and the possibility of warranty coaxial installation and to ensure the exit cross-sectional area of the gas-liquid dropper and nozzle mixture.

Claims (7)

1. A method of separating liquid from a gas stream, including swirling a gas-liquid stream, forming a rotating fluid layer on the surfaces of a cylindrical pipe and an axial body of revolution, separating the flows into liquid and gas phases and their subsequent selection, characterized in that at the maximum radius of the peripheral edge of the axial body rotation, equipped with inclined teeth, increase the thickness of the liquid layer and form discrete enlarged liquid droplets by exposing the liquid layers to a swirling gas flow m 2. The method of separating liquid from a gas stream according to claim 1, characterized in that the selection of liquid and gas is carried out separately. 3. The method of separating liquid from a gas stream according to claim 1, characterized in that the rotating liquid layer on the surface of the cylindrical nozzle is diaphragmed, while part of the liquid is taken directly before the diaphragm and the gas-liquid mixture is recycled after diaphragm. 4. A device for separating liquid from a gas stream, including a plate cloth with straight-through-centrifugal elements, each of which consists of a cylindrical nozzle with a swirl at the inlet and a separation device in the form of a cap film stripper at the outlet, an annular partition between the outer wall of the cylindrical nozzle and the inner wall cap film stripper, a displacer located inside the cylindrical nozzle, a recirculation channel, characterized in that the displacer is equipped with inclined teeth, located on its peripheral edge, and the inclination of the teeth is oriented towards the swirl of the gas stream, while the annular partition is made with oppositely arranged channels for the selection of liquid and gas phases, and the channels for the selection of the liquid phase are made at the maximum radius of the partition, and for the selection of the gas phase at its minimum radius. 5. A device for separating liquid from a gas stream according to claim 4, characterized in that an annular partition is located on the inner wall of the cylindrical pipe above the plate blade, directly above and below which there is a recirculation channel for supplying a gas-liquid mixture and a liquid withdrawal channel, and a peripheral edge the cylindrical nozzle is equipped with inclined teeth, the inclination of which is oriented towards the swirl of the gas stream. 6. A device for separating liquid from a gas stream according to claim 4, characterized in that the cylindrical pipe is made of a sheet in the form of a parallelogram, when connecting the sides of which a spiral joint is formed, oriented in the direction of movement of the gas-liquid stream. 7. A device for separating liquid from a gas stream according to claim 4, characterized in that the recirculation channel for supplying a gas-liquid mixture is made in the form of holes or a recirculation tube with central walls flanged upwards, on which the displacer is fixed.

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