Cascade tubular column type gas-liquid separation device

Abstract

The invention relates to a cascade tubular column type gas-liquid separation device which comprises a first-stage separation tubular column structure, the first-stage separation tubular column structure comprises a lower cylinder, at least one tangential inlet is formed in the top end of the side wall of the lower cylinder, a guide cylinder is arranged in the lower cylinder, and a first annular space is formed between the guide cylinder and the lower cylinder; the two-stage separation tubular column structure comprises an upper barrel, a gas phase outlet is formed in the top end of the upper barrel, an inner tubular column which extends downwards and penetrates out of the flow guide barrel is arranged in the upper barrel, the top end of the inner tubular column is closed, and an inner tubular side outlet is formed in the top end of the side wall of the inner tubular column. The inner tubular column and the guide cylinder are arranged at intervals to form a second annular space; and the liquid discharge pipe is arranged at the axis of the cascade tubular column type gas-liquid separation device, and the bottom end of the liquid discharge pipe is connected with the electric submersible pump. A multi-stage separation tubular column structure is adopted, and the natural gas produced gas is subjected to multiple times of cyclone separation; an annular gap is formed between the inner tubular column and the guide cylinder, and liquid flow flowing downwards through the annular gap forms a backflow liquid film, so that the phenomenon of carrying liquid in a gas phase is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas exploration and development, and in particular to a cascade column type gas-liquid separation device. Background Art

[0002] Natural gas hydrates, high-pressure gas (water-soluble gas) and deep-layer gas, the world's unconventional natural gas resources have great potential and broad development prospects. So far, the exploitation of natural gas has been relatively limited, and new technologies need further research, and various problems faced in the exploitation process need to be solved. With the further development of oil and gas exploration and development technology, the effective exploitation of unconventional natural gas will inevitably be realized, which is increasingly important for meeting the current growing energy demand. Unconventional natural gas will surely become a new generation of environmentally friendly, efficient and high-quality alternative energy. Natural gas hydrates are widely distributed in nature in the slopes of continents and islands, the uplifts of active and passive continental margins, the polar continental shelves, and the deep-water environments of oceans and some inland lakes.

[0003] After natural gas is extracted, it must be dehydrated and purified. In petrochemical plants, there are various gas phase deliquidation equipment. Among them, the column type gas-liquid separation device is widely used in various gas-liquid separation occasions due to its simple and compact structure, light weight, low energy consumption, low price, excellent performance, easy operation, simple maintenance and easy installation. The column type gas-liquid separation device has a mutually coupled separation mechanism of centrifugal gravity, which enables it to have efficient separation capabilities. However, the current column type gas-liquid separation device generally has the phenomenon of gas phase carrying liquid, resulting in poor liquid phase separation efficiency, which limits its engineering application.

[0004] Therefore, the inventor, relying on many years of experience and practice in related industries, proposes a cascade column type gas-liquid separation device to overcome the defects of the prior art. Summary of the invention

[0005] The object of the present invention is to provide a cascade pipe column type gas-liquid separation device, which adopts a multi-stage separation pipe column structure to perform multiple cyclone separations on natural gas production gas; an annular gap is arranged between the inner pipe column and the guide tube, and the liquid phase discharged into the upper cylinder can return to the lower cylinder through the annular gap to complete the gas-liquid separation, and the liquid flow flowing downward through the annular gap forms a reflux liquid film, which prevents the natural gas production gas from directly entering the inner pipe column in the form of short-circuit flow, thereby greatly reducing the gas phase carrying liquid phenomenon and improving the separation efficiency; a liquid discharge pipe is arranged at the axis of the entire gas-liquid separation device, which plays the role of a central stabilizing column, so that the cyclone field inside the lower cylinder and the inner pipe column is more stable, thereby ensuring the cyclone separation effect.

[0006] The object of the present invention is achieved by a cascade column type gas-liquid separation device, comprising:

[0007] The first-stage separation column structure comprises a lower cylinder with closed ends, at least one tangential inlet is arranged at the top of the side wall of the lower cylinder, a guide cylinder is coaxially arranged at a position corresponding to the tangential inlet in the lower cylinder, and both ends of the guide cylinder are open, and a first annular space capable of strong swirling of the produced natural gas is formed between the guide cylinder and the lower cylinder;

[0008] A two-stage separation column structure comprises an upper cylinder whose bottom end is connected to the lower cylinder, and the upper cylinder and the lower cylinder form an outer column; a gas phase outlet is arranged at the top of the upper cylinder, an inner column extending downward and passing through the guide cylinder is arranged in the upper cylinder, the top of the inner column is closed, and an inner tube side outlet is arranged at the top of the side wall of the inner column; the inner column and the guide cylinder are spaced to form a second annular space, and the second annular space can communicate with the inner cavities of the upper cylinder and the lower cylinder;

[0009] A liquid discharge pipe is arranged at the axis of the cascade column type gas-liquid separation device, and extends upward from the bottom end of the lower cylinder body through the lower cylinder body, the inner column, the upper cylinder body and the gas phase outlet. The bottom end of the liquid discharge pipe is connected to an electric submersible pump that provides liquid discharge power.

[0010] In a preferred embodiment of the present invention, a diameter reducing portion is provided on the outer wall of the drainage pipe at the connection between the upper cylinder and the lower cylinder, and a swirl blade capable of generating strong swirl on the produced natural gas is provided between the diameter reducing portion and the inner pipe column.

[0011] In a preferred embodiment of the present invention, an arc plate is connected to the outer wall of the lower cylinder at the position of the tangential inlet, and the flow area between the inner wall of the arc plate and the outer wall of the lower cylinder is gradually reduced. The produced natural gas is guided by the arc plate to rotate and accelerate through the tangential inlet to enter the first annular space to form a strong vortex to separate the gas-liquid two phases.

[0012] In a preferred embodiment of the present invention, the central angle of the tangential inlet on the circle where the cross section of the lower cylinder is located is greater than 60° and less than 90°.

[0013] In a preferred embodiment of the present invention, an upper shield plate is provided at the top end of the lower cylinder, a connecting hole is provided on the upper shield plate, and the connecting hole is connected to the guide cylinder extending downward; a lower shield plate is provided on the outer wall of the lower cylinder below the tangential inlet, and an inlet flow channel is formed between the lower shield plate, the arc plate and the upper shield plate, and the cross-sectional area of ​​the inlet flow channel is gradually reduced.

[0014] In a preferred embodiment of the present invention, the radial width of the second annular space is less than 1 / 5 of the inner diameter of the guide tube, and the length of the bottom end of the inner pipe column extending out of the guide tube is greater than 1 / 5 of the inner diameter of the guide tube and less than 2 / 3 of the inner diameter of the guide tube.

[0015] In a preferred embodiment of the present invention, a stop plate is provided at the top end of the inner pipe string, and the outer diameter of the stop plate is larger than the outer diameter of the inner pipe string.

[0016] In a preferred embodiment of the present invention, a conical cylinder with a diameter gradually decreasing from top to bottom is arranged in the lower cylinder below the guide cylinder, the bottom end of the conical cylinder is connected to the underflow pipe, and the electric submersible pump is arranged below the underflow pipe.

[0017] In a preferred embodiment of the present invention, a top cover plate is provided at the top end of the upper cylinder, a gas phase outlet pipe connected to the inner cavity of the upper cylinder is provided at the center of the top cover plate, and the inner cavity of the gas phase outlet pipe constitutes the gas phase outlet.

[0018] In a preferred embodiment of the present invention, the variable diameter portion includes a lower cone portion whose diameter gradually increases from bottom to top, the top end of the lower cone portion is connected to a cylindrical portion, and the top end of the cylindrical portion is connected to an upper cone portion whose diameter gradually decreases from bottom to top; the rotation-generating blade is arranged between the cylindrical portion and the inner pipe column.

[0019] As described above, the cascade column type gas-liquid separation device of the present invention has the following beneficial effects:

[0020] In the cascade column type gas-liquid separation device of the present invention, a multi-stage separation column structure is adopted to perform multiple cyclone separations on the produced natural gas; an annular gap is arranged between the inner column and the guide tube, and the liquid phase that enters the inner column with the gas phase and is discharged into the internal space of the upper cylinder from the inner tube side outlet can return to the lower cylinder through the annular gap to complete the gas-liquid separation, and the liquid flow flowing downward through the annular gap forms a reflux liquid film, which prevents the produced natural gas from directly entering the inner column in the form of short-circuit flow, thereby greatly reducing the gas phase carrying liquid phenomenon and improving the separation efficiency; a liquid discharge pipe is arranged at the axis of the entire gas-liquid separation device, which plays the role of a central stabilizing column, so that the cyclone field inside the lower cylinder and the inner column is more stable, thereby ensuring the cyclone separation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The following drawings are only intended to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0022] in:

[0023] Figure 1 : is a schematic diagram of the cascade column type gas-liquid separation device of the present invention.

[0024] Figure 2 :for Figure 1 Middle AA section view.

[0025] Figure 3 :for Figure 1 Middle BB section view.

[0026] In the figure:

[0027] 101. first annular space; 102. second annular space;

[0028] 1. Gas phase outlet pipe; 2. Top cover plate; 3. Flange; 4. Stop plate; 5. Upper cylinder; 6. Inner pipe column; 7. Upper shield plate; 8. Guide tube; 9. Lower shield plate; 10. Lower cylinder; 11. Cone; 12. Bottom flow pipe; 13. Curved plate; 14. Drain pipe; 15. Variable diameter part; 16. Swirl blade; 17. Submersible pump; 18. Tangential inlet; 19. Gas phase outlet; 20. Inner pipe side outlet. DETAILED DESCRIPTION

[0029] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0030] The specific embodiments of the present invention described herein are only used to explain the purpose of the present invention and cannot be understood as limiting the present invention in any way. Under the guidance of the present invention, technicians can conceive of any possible variations based on the present invention, which should be considered to belong to the scope of the present invention. It should be noted that when an element is referred to as "arranged on" another element, it can be directly on the other element or there can also be a central element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a central element at the same time. The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be the internal communication of two elements, it can be directly connected, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation method.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0032] like Figure 1 , Figure 2 , Figure 3 As shown, the present invention provides a cascade column type gas-liquid separation device, comprising:

[0033] The first-stage separation column structure comprises a lower cylinder 10 with closed ends, at least one tangential inlet 18 is arranged at the top of the side wall of the lower cylinder 10, a guide cylinder 8 is coaxially arranged at a position corresponding to the tangential inlet 18 in the lower cylinder 10, and both ends of the guide cylinder 8 are open, and a first annular space 101 capable of strong swirling of the produced natural gas is formed between the guide cylinder 8 and the lower cylinder 10;

[0034] The secondary separation column structure comprises an upper cylinder 5 whose bottom end is connected to a lower cylinder 10, and the upper cylinder 5 and the lower cylinder 10 form an outer column; the upper cylinder 5 and the lower cylinder 10 are coaxially arranged; a gas phase outlet 19 is arranged at the top of the upper cylinder 5, an inner column 6 extending downward and passing through the guide cylinder 8 is arranged in the upper cylinder 5, the top of the inner column 6 is closed, and an inner tube side outlet 20 is arranged at the top of the side wall of the inner column 6; the inner column 6 and the guide cylinder 8 are spaced to form a second annular space 102, and the second annular space 102 can communicate with the inner cavities of the upper cylinder 5 and the lower cylinder 10;

[0035] The drainage pipe 14 is arranged at the axis center of the cascade column type gas-liquid separation device, extending upward from the bottom end of the lower cylinder 10 through the lower cylinder 10, the inner column 6, the upper cylinder 5 and the gas phase outlet 19. The bottom end of the drainage pipe 14 is connected to the electric submersible pump 17 that provides drainage power.

[0036] The outer pipe column is composed of an upper cylinder 5 and a lower cylinder 10. The entire outer pipe column can be arranged in a three-dimensional manner, and according to actual working conditions, a support member can be added at the bottom of the outer pipe column to enhance the stability of the pipe column gas-liquid separation device.

[0037] The connection portion between the upper cylinder 5 and the lower cylinder 10 is located in the middle of the outer pipe column, and the tangential inlet 18 is arranged at this position. One or two tangential inlets 18 can be arranged, and the number is determined according to the actual working conditions.

[0038] The produced natural gas enters the first annular space 101 through the tangential inlet to form a strong vortex to separate the gas-liquid two phases. The water in the heavy phase is gradually gathered to the inner wall of the lower cylinder 10 by centrifugal force and converges downward under the action of gravity. The light phase natural gas refluxes upward to form a core flow (the bottom end of the lower cylinder 10 is closed, which can make the natural gas reflux upward to form a core flow), and enters the internal space of the inner pipe column 6 and flows upward along the inner pipe column 6, forming a strong vortex field again in the inner pipe column 6. Under the separation effect of the strong vortex field and the impact effect of the natural gas and the closed top of the inner pipe column, the aggregation and separation of the liquid phase components in the natural gas are further realized; and the vortex field inside the lower cylinder 10 and the inner pipe column 6 is more stable under the steady flow guiding effect of the axial discharge pipe 14.

[0039] The gas phase discharged from the inner tube side outlet 20 of the inner tube column 6 continues to flow upward inside the upper cylinder 5, and is finally discharged from the gas phase outlet 19, while the liquid phase discharged from the inner tube side outlet 20 of the inner tube column 6 flows downward under the action of gravity, and flows down from the second annular space 102 (annular gap) between the inner tube column 6 and the guide tube 8 to the internal space of the lower cylinder 10, and finally gathers at the bottom of the lower cylinder 10, and is driven by the electric submersible pump 17 to be discharged from the upper end through the discharge pipe 14, completing the separation of the gas phase and the liquid phase in the produced natural gas. The liquid flow flowing downward through the second annular space 102 (annular gap) forms a reflux liquid film, which prevents the produced natural gas from directly entering the inner tube column 6 in the form of short-circuit flow, thereby greatly reducing the gas phase carrying liquid phenomenon and improving the separation efficiency.

[0040] In the cascade column type gas-liquid separation device of the present invention, a multi-stage separation column structure is adopted to perform multiple cyclone separations on the natural gas production gas; an annular gap (second annular space 102) is arranged between the inner column 6 and the guide tube 8, and the liquid phase that enters the inner column 6 with the gas phase and is discharged into the internal space of the upper cylinder 5 from the inner tube side outlet 20 can return to the lower cylinder 10 through the annular gap to complete the gas-liquid separation, and the liquid flow flowing downward through the annular gap forms a reflux liquid film, which prevents the natural gas production gas from directly entering the inner column 6 in the form of short-circuit flow, thereby greatly reducing the gas phase carrying liquid phenomenon and improving the separation efficiency; a discharge pipe 14 is arranged at the axis of the entire gas-liquid separation device, which plays the role of a central stabilizing column, so that the cyclone field inside the lower cylinder 10 and the inner column 6 is more stable, thereby ensuring the cyclone separation effect.

[0041] Further, if Figure 1 As shown, a reducing portion 15 is provided on the outer wall of the liquid discharge pipe 14 at the connection between the upper cylinder 5 and the lower cylinder 10, and a swirl blade 16 capable of strongly swirling the produced natural gas is provided between the reducing portion 15 and the inner pipe column 6. The swirl blade 16 strengthens the rotation intensity of the swirl flow field in the inner pipe column 6 and strengthens the secondary separation effect.

[0042] The reducing portion 15 is a solid structure, which enlarges the inner diameter of the annular flow channel between the discharge pipe 14 and the inner pipe column 6 to reduce the flow area, and a swirl blade 16 is provided between the reducing portion 15 and the inner pipe column 6. The swirl blade 16 swirls the rising flow in the inner pipe column 6 (generated by the action of the cone 11) again to produce enhanced swirl separation, thereby enhancing the separation efficiency of the entire gas-liquid separation device.

[0043] In a specific embodiment of the present invention, the variable diameter portion 15 includes a lower cone portion whose diameter gradually increases from bottom to top, the top end of the lower cone portion is connected to the cylindrical portion, and the top end of the cylindrical portion is connected to an upper cone portion whose diameter gradually decreases from bottom to top; a swirl blade 16 is arranged between the cylindrical portion and the inner pipe column 6 (using existing technology).

[0044] Further, if Figure 1 , Figure 2 As shown, the arc plate 13 is connected to the position of the tangential inlet 18 on the outer wall of the lower cylinder 10, and the flow area between the inner wall of the arc plate 13 and the outer wall of the lower cylinder 10 is gradually reduced. The natural gas produced is guided by the arc plate 13 to rotate and accelerate through the tangential inlet 18 to enter the first annular space 101 to form a strong vortex to separate the gas-liquid two phases.

[0045] The tangential inlet 18 is a rectangular opening arranged on the side wall of the lower cylinder 10, and an arc plate 13 is extended and connected to one side of the rectangular opening. The arc plate 13 is tangentially connected to the outer wall surface of the lower cylinder 10, and extends outward from the tangential connection to completely cover the tangential inlet and continues to expand for a certain distance. In this embodiment, the arc plate 13 extends outward from the tangential connection with the outer wall surface of the lower cylinder 10 to cover a range of 90 degrees, thereby covering the tangential inlet 18.

[0046] An inlet for natural gas production gas to enter is formed between the outer wall surface of the lower cylinder 10 and the side of the arc plate 13 away from the lower cylinder 10. The flow channel area between the inlet and the tangential inlet 18 gradually decreases. After entering from the inlet, the natural gas production gas is first guided by the arc plate 13, thereby rotating into the tangential inlet 18 of the lower cylinder 10. Under the influence of the gradually decreasing flow channel area, the flow velocity of the natural gas production gas increases, and a strong vortex is formed in the first annular space 101 (between the inner wall surface of the lower cylinder 10 and the guide tube 8), thereby realizing the two-phase separation of gas and liquid.

[0047] Furthermore, one or two tangential inlets 18 are provided. In a specific embodiment, two tangential inlets 18 are provided, and the two tangential inlets 18 are rotationally symmetrically distributed along the central axis of the lower cylinder 10, and the central angle α of the rectangular opening of each tangential inlet 18 along the circle where the cross section of the lower cylinder 10 is located is greater than 60° and less than 90°. Figure 2 As shown, Figure 1 The AA cross-sectional view in the middle omits the visual field structure of the drainage pipe 14 and the electric submersible pump 17, and specifically shows the schematic diagram of the tangential inlet structure of the cascade column gas-liquid separation device of the present invention. Figure 2 The schematic diagram of the embodiment when two tangential inlets 18 are provided is shown, and the points of the two tangential inlets 18 along the central axis of the outer pipe string (lower cylinder 10) are distributed in rotational symmetry.

[0048] In this specific embodiment, a line is drawn from the side of the tangential inlet 18 that is not tangentially connected to the arc plate 13 to the center of the lower cylinder 10. Figure 2 The angle between the middle horizontal center lines is 28°, that is, a line is drawn from one side where the tangential inlet 18 is tangentially connected to the arc plate 13 to the center of the lower cylinder 10, and a line is drawn from the other side that is not in contact with the arc plate 13 to the center of the lower cylinder 10, and the angle between the two lines is greater than 60°.

[0049] Further, if Figure 1 As shown, an upper shield plate 7 is arranged at the top of the lower cylinder 10, and a connecting hole is arranged on the upper shield plate 7, and the connecting hole is connected to the guide cylinder 8 extending downward; a lower shield plate 9 is arranged on the outer wall of the lower cylinder 10 below the tangential inlet 18, and an inlet flow channel is formed between the lower shield plate 9, the arc plate 13 and the upper shield plate 7, and the cross-sectional area of ​​the inlet flow channel is gradually reduced.

[0050] The present invention redesigns the structure of the tangential inlet, and utilizes the structural shape of the arc plate to form a bell-mouth-like flow channel with a gradually decreasing flow channel area. After the natural gas production gas enters from the inlet, it is first guided by the arc plate, thereby rotating into the tangential inlet 18 of the lower cylinder 10, and under the influence of the gradually decreasing flow channel area, the flow velocity of the natural gas production gas increases, thereby increasing the cyclone intensity, which is beneficial to improving the separation efficiency.

[0051] Furthermore, the inner pipe column 6 is connected and fixed to the guide tube 8 through a support rod to achieve the positioning of the inner pipe column 6 inside the outer pipe column.

[0052] Furthermore, the radial width of the second annular space 102 is less than 1 / 5 of the inner diameter of the guide tube, and the length of the bottom end of the inner pipe column extending out of the guide tube is greater than 1 / 5 of the inner diameter of the guide tube and less than 2 / 3 of the inner diameter of the guide tube.

[0053] In a specific embodiment of the present invention (DN100 pilot test device), the inner diameter of the outer pipe column (upper cylinder 5 and lower cylinder 10) is 100 mm, the inner diameter of the guide tube 8 is 58 mm, the inner diameter of the inner pipe column is 40 mm, the radial width of the second annular space 102 is 5 mm, and the length of the lower end of the inner pipe column 6 extending out of the guide tube 8 is 20 mm. The pilot device within this size limit basically eliminates the occurrence of liquid carryover, and the gas-liquid separation efficiency is greatly improved compared with the traditional column-type gas-liquid separation equipment.

[0054] Further, if Figure 1 As shown, a stop plate 4 is provided at the top end of the inner pipe column 6, and the outer diameter of the stop plate 4 is larger than the outer diameter of the inner pipe column 6. The stop plate 4 seals the top end of the inner pipe column 6.

[0055] In a specific embodiment, two inner tube side outlets 20 are symmetrically arranged on the side wall of the inner tube column 6. Figure 3 As shown (the view of the discharge pipe 14, the reducing portion 15, and the swirl blades 16 are omitted), a structural relationship diagram of the two inner tube side outlets 20 at the top end of the side wall of the inner tube column is specifically shown.

[0056] The rising natural gas flow in the inner pipe column 6 (at the center position of the cascade pipe column gas-liquid separation device of the present invention) is blocked by the stop plate 4 and flows out of the inner pipe column 6 from the two inner pipe side outlets 20. Under the impact of the stop plate 4, the aggregation and descent of the trace liquid phase carried in the gas phase are promoted, thereby enhancing the separation effect.

[0057] Further, if Figure 1 As shown, a conical cylinder 11 with a diameter gradually decreasing from top to bottom is arranged in the lower cylinder 10 below the guide cylinder 8 , and the bottom end of the conical cylinder 11 is connected to the underflow pipe 12 , and an electric submersible pump 17 is arranged below the underflow pipe 12 .

[0058] Further, if Figure 1 As shown, a top cover plate 2 is provided at the top end of the upper cylinder 5, and the top cover plate 2 is connected to the upper cylinder 5 through a flange 3; a gas phase outlet pipe 1 connected to the inner cavity of the upper cylinder 5 is provided at the center of the top cover plate 2, and the inner cavity of the gas phase outlet pipe 1 constitutes a gas phase outlet 19.

[0059] The drain pipe 14 is located at the axis of the entire cascade column gas-liquid separation device. The top end of the drain pipe 14 passes through the gas phase outlet pipe 1 and is connected to an external pipeline or equipment to discharge the liquid phase. The lower end of the drain pipe 14 is connected to an electric submersible pump 17 installed at the bottom of the outer column (lower cylinder 10). The electric submersible pump 17 provides power for discharging the liquid phase from the upper end.

[0060] The working principle of the cascade column type gas-liquid separation device of the present invention is as follows:

[0061] The produced natural gas enters from the two tangential inlets 18 of the present invention, and enters the first annular space 101 (the annular space between the outer pipe column and the guide tube 8) and forms a strong vortex under the flow-guiding and vortex-generating effect of the arc plate 13 and the flow channel structure with a gradually shrinking flow channel area between the arc plate 13 and the wall of the outer pipe column, and forms a strong vortex. The heavy phase of water is gradually gathered to the inner wall of the outer pipe column by centrifugal force and converges downward under the action of gravity. The light phase of natural gas refluxes upward to form a core flow, and enters the internal space of the inner pipe column 6 and flows upward along the inner pipe column 6, forming a strong vortex field again in the inner pipe column 6, and the vortex-generating blades 16 perform a secondary enhanced vortex. The separation effect of the strong vortex field and the impact-stopping effect of the natural gas and the impact-stopping plate 4 at the top of the inner pipe column further realize the aggregation and separation of the liquid phase components in the natural gas; and the vortex field inside the lower cylinder 10 and the inner pipe column 6 is more stable under the steady flow guiding effect of the axial discharge pipe 14.

[0062] The gas phase discharged from the inner tube side outlet 20 (the side outlet near the upper port) of the inner pipe column 6 continues to flow upward inside the upper cylinder 5 and is finally discharged from the gas phase outlet pipe 1, while the liquid phase discharged from the inner tube side outlet 20 of the inner pipe column 6 flows downward under the action of gravity, and flows down from the second annular space 102 (the annular gap between the inner pipe column 6 and the guide tube 8) to the internal space of the lower cylinder 10, and finally gathers to the bottom flow pipe 12 and is discharged to the bottom of the lower cylinder 10, and is driven by the electric submersible pump 17 to be discharged from the upper end through the discharge pipe 14, completing the separation of the gas phase and the liquid phase in the produced natural gas. The liquid flow flowing downward through the annular gap forms a reflux liquid film, which prevents the produced natural gas from directly entering the inner pipe column in the form of short-circuit flow, thereby greatly reducing the gas-phase liquid carrying phenomenon and improving the separation efficiency.

[0063] As described above, the cascade column type gas-liquid separation device of the present invention has the following beneficial effects:

[0064] In the cascade column type gas-liquid separation device of the present invention, a multi-stage separation column structure is adopted to perform multiple cyclone separations on the produced natural gas; an annular gap is arranged between the inner column and the guide tube, and the liquid phase that enters the inner column with the gas phase and is discharged into the internal space of the upper cylinder from the inner tube side outlet can return to the lower cylinder through the annular gap to complete the gas-liquid separation, and the liquid flow flowing downward through the annular gap forms a reflux liquid film, which prevents the produced natural gas from directly entering the inner column in the form of short-circuit flow, thereby greatly reducing the gas phase carrying liquid phenomenon and improving the separation efficiency; a liquid discharge pipe is arranged at the axis of the entire gas-liquid separation device, which plays the role of a central stabilizing column, so that the cyclone field inside the lower cylinder and the inner column is more stable, thereby ensuring the cyclone separation effect.

[0065] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A cascade column type gas-liquid separation device, It is characterized in that include, The first-stage separation column structure comprises a lower cylinder with closed ends, at least one tangential inlet is arranged at the top of the side wall of the lower cylinder, a guide cylinder is coaxially arranged at a position corresponding to the tangential inlet in the lower cylinder, and both ends of the guide cylinder are open, and a first annular space capable of strong swirling of the produced natural gas is formed between the guide cylinder and the lower cylinder; A two-stage separation column structure comprises an upper cylinder whose bottom end is connected to the lower cylinder, and the upper cylinder and the lower cylinder form an outer column; a gas phase outlet is arranged at the top of the upper cylinder, an inner column extending downward and passing through the guide cylinder is arranged in the upper cylinder, the top of the inner column is closed, and an inner tube side outlet is arranged at the top of the side wall of the inner column; the inner column and the guide cylinder are spaced to form a second annular space, and the second annular space can communicate with the inner cavities of the upper cylinder and the lower cylinder; A liquid discharge pipe is arranged at the axis of the cascade column type gas-liquid separation device, and extends upward from the bottom end of the lower cylinder body through the lower cylinder body, the inner column, the upper cylinder body and the gas phase outlet. The bottom end of the liquid discharge pipe is connected to an electric submersible pump that provides liquid discharge power.

2. The cascade column type gas-liquid separation device according to claim 1, It is characterized in that A diameter reducing portion is arranged on the outer wall of the liquid discharge pipe at the connection between the upper cylinder and the lower cylinder, and a swirl blade capable of generating strong swirl for the produced natural gas is arranged between the diameter reducing portion and the inner pipe column.

3. The cascade column type gas-liquid separation device according to claim 2, It is characterized in that An arc plate is connected to the outer wall of the lower cylinder at the position of the tangential inlet, and the flow area between the inner wall of the arc plate and the outer wall of the lower cylinder is gradually reduced. The produced natural gas is guided by the arc plate to rotate and accelerate through the tangential inlet to enter the first annular space to form a strong vortex to separate the gas-liquid two phases.

4. The cascade column type gas-liquid separation device according to claim 3, It is characterized in that The central angle of the tangential inlet on the circle where the cross section of the lower cylinder is located is greater than 60° and less than 90°.

5. The cascade column type gas-liquid separation device according to claim 3, It is characterized in that An upper shield plate is arranged on the top of the lower cylinder, and a connecting hole is arranged on the upper shield plate, and the connecting hole is connected to the guide cylinder extending downward; a lower shield plate is arranged on the outer wall of the lower cylinder below the tangential inlet, and an inlet flow channel is formed between the lower shield plate, the arc plate and the upper shield plate, and the cross-sectional area of ​​the inlet flow channel is gradually reduced.

6. The cascade column type gas-liquid separation device according to claim 3, It is characterized in that The radial width of the second annular space is less than 1 / 5 of the inner diameter of the guide tube, and the length of the bottom end of the inner pipe column extending out of the guide tube is greater than 1 / 5 of the inner diameter of the guide tube and less than 2 / 3 of the inner diameter of the guide tube.

7. The cascade column type gas-liquid separation device according to claim 3, It is characterized in that A stop plate is arranged at the top end of the inner pipe column, and the outer diameter of the stop plate is larger than the outer diameter of the inner pipe column.

8. The cascade column type gas-liquid separation device according to claim 3, It is characterized in that A conical cylinder with a diameter gradually decreasing from top to bottom is arranged in the lower cylinder body below the guide cylinder, the bottom end of the conical cylinder is connected to the underflow pipe, and the electric submersible pump is arranged below the underflow pipe.

9. The cascade column type gas-liquid separation device according to claim 3, It is characterized in that A top cover plate is arranged at the top end of the upper cylinder, a gas phase outlet pipe communicating with the inner cavity of the upper cylinder is arranged at the center of the top cover plate, and the inner cavity of the gas phase outlet pipe constitutes the gas phase outlet.

10. The cascade column type gas-liquid separation device according to claim 2, It is characterized in that The variable diameter portion includes a lower cone portion whose diameter gradually increases from bottom to top, the top end of the lower cone portion is connected to the cylindrical portion, and the top end of the cylindrical portion is connected to an upper cone portion whose diameter gradually decreases from bottom to top; the swirl blade is arranged between the cylindrical portion and the inner pipe column.

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