Two-stage synergistic degassing type tubular gas-liquid separator

Abstract

The invention provides a two-stage synergistic degassing type tubular gas-liquid separator which comprises an outer pipe, an axial static swirling element and a central exhaust pipe, and the interior of the outer pipe is divided into a first-stage gas-liquid separation section and a second-stage gas-liquid separation section; the axial static rotation starting element is located on the first-stage gas-liquid separation section and comprises a central cylinder, rotation starting blades are arranged on the central cylinder and are of a spiral structure, and the outer edges of the rotation starting blades are tightly attached to the inner wall of the outer pipe; the central exhaust pipe is communicated with the first-stage gas-liquid separation section and the second-stage gas-liquid separation section, an annular space exists between the central exhaust pipe and the outer pipe, an annular slit is formed in the peripheral wall of an outlet section of the central exhaust pipe, the annular slit is located in the second-stage gas-liquid separation section, and a second-stage liquid phase outlet is located below the annular slit. Through the synergistic effect of the two gas-liquid separation processes, the problems that an existing degassing type tubular gas-liquid separator is poor in separation efficiency, gas and liquid outlets cannot reach the standard at the same time, and the occupied space is large can be effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of gas-liquid separation in oil and gas field gathering and transportation processing technology, and in particular to a two-stage coordinated degassing type tubular gas-liquid separator. Background Art

[0002] Gas-liquid separation is an essential and key link in oil and gas gathering and transportation in offshore and onshore oil and gas fields. Compared with conventional tank or tower gas-liquid separation equipment, tubular gas-liquid separators have attracted great attention due to their compact structure, high separation efficiency, and ease of modular production. Tubular gas-liquid separators can be divided into deliquescence type (gas content > 0.1), phase separation type (gas content 0.2-0.95) and degassing type (gas content < 0.6) according to the different inlet gas content. According to the working principle, they can be divided into gravity type, centrifugal type, hybrid type, etc. At present, degassing tubular gas-liquid separators still have problems such as incomplete gas-liquid separation and difficulty in achieving the standards for gas and liquid outlets at the same time. Therefore, it is of great significance to develop an efficient and compact two-stage coordinated degassing tubular gas-liquid separator.

[0003] Domestic and foreign scholars have conducted relevant research on degassing gas-liquid separators based on gravity sedimentation. For example, in 2018, Ye Weidong and others from Northeast Petroleum University designed a gravity gas-liquid separator and performed numerical simulations on it to address the problem of high gas content in oil production. The results showed that the larger the inner diameter of the outer tube of the gravity gas-liquid separator and the smaller the outer diameter of the central tube, the better the separation effect; the "vertical gas-liquid two-phase gravity separator for geothermal deep wellheads" proposed in patent ZL201520123254.2 uses the gravity sedimentation separation principle to process gas-containing liquids with large flow rates. But objectively speaking, the separation effect that can be achieved by relying solely on gravity sedimentation is very poor, and the corresponding equipment is large in size and the structure is not compact and centralized enough.

[0004] The applicant has discovered that the prior art has at least the following technical problems: Although the degassing tubular gas-liquid separator has been applied to the field of oil and gas field gathering and transportation, the degassing tubular gas-liquid separator in the prior art still has problems such as a narrow range of adaptable working conditions, failure to meet the simultaneous gas and liquid outlet standards, and difficulty in modular production. The most important problem is that the gas-liquid separator in the prior art has poor separation efficiency, which limits its application in industrial production. Summary of the invention

[0005] The purpose of the present invention is to provide a two-stage coordinated degassing tubular gas-liquid separator to solve the technical problem of poor separation efficiency of gas-liquid separators in the prior art. The preferred technical solutions among the many technical solutions provided by the present invention can produce many technical effects as described below.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The two-stage coordinated degassing tubular gas-liquid separator provided by the present invention comprises an outer tube having a gas-liquid mixture inlet and a gas phase outlet, an axial stationary swirl element located in the outer tube, and a central exhaust pipe, wherein:

[0008] The outer tube is divided into a primary gas-liquid separation section having a primary liquid phase outlet and a secondary gas-liquid separation section having a secondary liquid phase outlet;

[0009] The axial static rotating element is located in the primary gas-liquid separation section, and the axial static rotating element comprises a central cylinder, on which rotating blades are arranged, the rotating blades are in a spiral structure, and the outer edge of the rotating blades is tightly fitted with the inner wall of the outer tube;

[0010] The central exhaust pipe is connected to the primary gas-liquid separation section and the secondary gas-liquid separation section. An annular space exists between the central exhaust pipe and the outer pipe. An annular slit is provided on the outer peripheral wall of the outlet section of the central exhaust pipe. The annular slit is located in the secondary gas-liquid separation section, and the secondary liquid phase outlet is located below the annular slit.

[0011] Preferably, the axial stationary rotating element further comprises an end ellipsoidal body guide, the end ellipsoidal body guide is fixed to the windward end of the central cylinder, and the convex surface of the end ellipsoidal body guide is the windward surface.

[0012] Preferably, the axial stationary rotating element further comprises a tail end conical guide body, the tail end conical guide body is fixed to the leeward end of the central cylinder, and the conical end surface of the tail end conical guide body is the leeward surface.

[0013] Preferably, the rotating blades are evenly spaced in the circumferential direction of the central cylinder.

[0014] Preferably, the central exhaust pipe comprises an end baffle, a hollow column section and a hollow cone section, wherein:

[0015] The hollow cone section is fixedly connected to the air inlet end of the hollow column section, the inner diameter of the hollow cone section gradually decreases in the direction away from the hollow column section, the annular slit is located on the peripheral wall of the hollow column section, the end baffle is fixed to the air outlet end of the hollow column section, and the end baffle is provided with an air outlet hole.

[0016] Preferably, the annular slits are evenly spaced and arranged on the peripheral wall of the hollow column section.

[0017] Preferably, the axial stationary rotating element, the central exhaust pipe and the outer pipe are arranged coaxially.

[0018] Preferably, an annular baffle is fixed inside the outer tube, and the inner ring of the annular baffle is fixedly connected to the outer wall of the central exhaust pipe. The area between the gas-liquid mixture inlet and the annular baffle is the primary gas-liquid separation section, and the area between the annular baffle and the gas phase outlet is the secondary gas-liquid separation section.

[0019] Preferably, the ratio of the length of the rotating blade to the length of the central cylinder is 0.5-1, the number of the rotating blades is 5-8, and the cone angle range of the tail end conical guide body is 25-60°.

[0020] Preferably, the ratio of the diameter of the hollow column section to the diameter of the end baffle is 0.5-0.75, and the cone angle of the hollow cone section is in the range of 3-5°.

[0021] The two-stage cooperative degassing tubular gas-liquid separator provided by the present invention has the following beneficial effects compared with the prior art: the two-stage cooperative degassing tubular gas-liquid separator provided by the present invention can realize two gas-liquid separations, separate the gas phase step by step, effectively prevent the gas phase from escaping from the primary liquid phase outlet and the secondary liquid phase outlet, and promote the gas and liquid outlets to meet the standards at the same time. Through the primary gas-liquid separation section, the first gas-liquid separation is achieved under the strong centrifugal force of the swirling blades to ensure that the primary liquid outlet meets the standards; the structure of the central exhaust pipe and the axial static swirling element can maximize the stability and separation effect of the gas core while ensuring the compact structure. The gas core carrying the liquid phase still has a certain swirling effect after entering the central exhaust pipe, and the liquid phase entrained in the gas phase can be thrown to the outer wall of the central exhaust pipe, and enter the annular space between the central exhaust pipe and the outer pipe through the annular slit, and further perform gravity sedimentation separation, and the pure gas phase is discharged from the gas phase outlet, realizing the second separation of the gas and liquid phases, thereby ensuring that the gas content rate of the secondary liquid outlet and the liquid content rate of the gas phase outlet meet the standards at the same time. The synergistic effect of the two gas-liquid separation processes can effectively overcome the problems of the current degassing tubular gas-liquid separator, such as poor separation efficiency, inability to meet the simultaneous gas and liquid outlet standards, and large space occupation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a cross-sectional schematic diagram of a two-stage coordinated degassing tubular gas-liquid separator provided by an embodiment of the present invention;

[0024] Figure 2is a front schematic view of an axially stationary rotating element provided by an embodiment of the present invention;

[0025] Figure 3 It is a front view schematic diagram of a central exhaust pipe provided in an embodiment of the present invention.

[0026] In the figure, 1, outer tube; 2, axial stationary rotating element; 21, tail end conical guide body; 22, central cylinder; 23, end ellipsoidal guide body; 24, rotating blades; 3, central exhaust pipe; 31, end baffle; 32, annular slit; 33, hollow column section; 34, hollow cone section; 4, primary liquid phase outlet; 5, secondary liquid phase outlet; 6, annular baffle; 7, gas phase outlet; 8, gas-liquid mixture inlet. DETAILED DESCRIPTION

[0027] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0028] In the description of the present invention, it should be understood that the terms "center", "length", "width", "height", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "side" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0029] The embodiment of the present invention provides a two-stage coordinated degassing tubular gas-liquid separator, which utilizes the two-stage coordination of secondary gas-liquid cyclone + gravity sedimentation separation to achieve efficient separation of gas and liquid in a limited tubular space.

[0030] Combine the following Figure 1-Figure 3 The technical solution provided by the present invention is described in more detail.

[0031] like Figure 1-Figure 3As shown, the two-stage collaborative degassing tubular gas-liquid separator provided by the present invention comprises an outer tube 1 having a gas-liquid mixture inlet 8 and a gas phase outlet 7, an axial stationary swirling element 2 located in the outer tube 1, and a central exhaust pipe 3, wherein: the outer tube 1 is divided into a primary gas-liquid separation section having a primary liquid phase outlet 4 and a secondary gas-liquid separation section having a secondary liquid phase outlet 5; the axial stationary swirling element 2 is located in the primary gas-liquid separation section, the axial stationary swirling element 2 comprises a central cylinder 22, on which swirling blades 24 are arranged, the swirling blades 24 are in a spiral structure, and the outer edges of the swirling blades 24 are tightly fitted with the inner wall of the outer tube 1; the central exhaust pipe 3 connects the primary gas-liquid separation section and the secondary gas-liquid separation section, there is an annular space between the central exhaust pipe 3 and the outer tube 1, an annular slit 32 is arranged on the outer peripheral wall of the outlet section of the central exhaust pipe 3, the annular slit 32 is located in the secondary gas-liquid separation section, and the secondary liquid phase outlet 5 is located below the annular slit 32.

[0032] The working principle is as follows: after the gas-liquid mixture enters from the gas-liquid mixture inlet 8, the strong centrifugal effect of the swirl generated by the axially stationary swirl element 2 causes the liquid phase with higher density to gather near the inner wall of the outer tube 1 and be discharged from the first-level liquid phase outlet 4, ensuring that the first-level liquid phase outlet 4 meets the standards, and the gas phase with lower density forms a gas core and gathers at the center of the pipeline, and enters the second-level gas-liquid separation section from the central exhaust pipe 3; the purpose of setting the second-level gas-liquid separation section is to separate the gas and liquid phases that have not been completely separated in the first stage again. The gas and liquid phases entering the central exhaust pipe 3 still have a certain swirl intensity due to inertia, and part of the liquid phase carried in the gas phase is thrown to the inner wall of the central exhaust pipe 3, and falls into the second-level gas-liquid separation section through the annular slit 32 by gravity, and is discharged from the second-level liquid phase outlet 5. The pure gas phase after the second-level separation is discharged from the gas phase outlet 7.

[0033] The present invention provides a two-stage collaborative degassing tubular gas-liquid separator. The first stage adopts gas-liquid cyclone centrifugal separation, and the second stage adopts gas-liquid cyclone + gravity sedimentation separation. The two stages collaborate to achieve simultaneous gas and liquid outlet compliance, and have the advantages of compact structure and easy modular design.

[0034] The structure of the axial stationary rotating element 2 in this embodiment is as follows: Figure 1 and Figure 2As shown, the axial stationary rotating element 2 also includes an end ellipsoidal flow guide 23, which is fixed to the windward end of the central cylinder 22, and the convex surface of the end ellipsoidal flow guide 23 is the windward surface. The axial stationary rotating element 2 also includes a tail end conical flow guide 21, which is fixed to the leeward end of the central cylinder 22, and the conical end surface of the tail end conical flow guide 21 is the leeward surface. The rotating blades 24 are evenly spaced in the circumferential direction of the central cylinder 22. The ratio of the length of the rotating blades 24 to the length of the central cylinder 22 is 0.5-1, the number of the rotating blades 24 is 5-8, and the cone angle range of the tail end conical flow guide 21 is 25-60°.

[0035] The convex surface of the end ellipsoidal flow guide 23 is the windward surface, which facilitates guiding the airflow to shear and break into uniform micro droplets.

[0036] The gas-liquid flow is sheared and broken through the end ellipsoidal guide body 23, and enters the spiral guide space between the swirling blades 24 and the inner wall of the outer tube 1, generating a swirling centrifugal force, causing the liquid phase with a higher density to converge near the inner wall of the outer tube 1. Under the guidance of the tail end conical guide body 21, the gas phase is mixed with the unseparated liquid phase and enters the central exhaust pipe 3.

[0037] Regarding the structure of the central exhaust pipe 3 in this embodiment: the central exhaust pipe 3 includes an end baffle 31, a hollow column section 33 and a hollow cone section 34, wherein: the hollow cone section 34 is fixedly connected to the air inlet end of the hollow column section 33, the inner diameter of the hollow cone section 34 gradually decreases in the direction away from the hollow column section 33, the annular slit 32 is located on the peripheral wall of the hollow column section 33, the end baffle 31 is fixed to the air outlet end of the hollow column section 33, and an air outlet hole is provided on the end baffle 31. The annular slits 32 are evenly spaced and arranged on the peripheral wall of the hollow column section 33. The hollow cone section 34 facilitates the concentrated airflow to enter the central exhaust pipe 3.

[0038] The gas-liquid two phases that are not completely separated in the first stage are separated again. The gas-liquid two phases that enter the central exhaust pipe 3 still have sufficient cyclone intensity due to inertia. Part of the liquid phase carried in the gas phase is thrown to the inner wall of the central exhaust pipe 3, and the liquid phase is thrown into the annular space between the central exhaust pipe 3 and the outer pipe 1 from the annular slit 32, and is discharged from the secondary liquid phase outlet 5 under the action of gravity.

[0039] The end baffle 31 restricts the outflow of the liquid phase, and the gas phase after the secondary separation is discharged from the gas outlet holes on the end baffle 31 .

[0040] As an optional implementation, the axial stationary swirling element 2, the central exhaust pipe 3 and the outer tube 1 are arranged coaxially, which can ensure the stability of the gas core while ensuring a compact structure. The central exhaust pipe 3 can utilize the gas-liquid cyclone effect in the primary gas-liquid separation section to perform gas-liquid cyclone separation.

[0041] As an optional embodiment, an annular baffle 6 is fixed inside the outer tube 1, and the inner ring of the annular baffle 6 is fixedly connected to the outer wall of the central exhaust pipe 3. The area between the gas-liquid mixture inlet 8 and the annular baffle 6 is a primary gas-liquid separation section, and the area between the annular baffle 6 and the gas phase outlet 7 is a secondary gas-liquid separation section. The annular baffle 6 is sealed and fixed to the inner wall of the outer tube 1 by welding or flange connection to form a two-stage gas-liquid separation section.

[0042] As an optional embodiment, the ratio of the diameter of the hollow column section 33 to the diameter of the end baffle 31 is 0.5-0.75, and the cone angle of the hollow cone section 34 is in the range of 3-5°.

[0043] The present invention provides a two-stage coordinated degassing tubular gas-liquid separator, which mainly realizes two gas-liquid separations in a limited tubular space through the first-stage gas-liquid cyclone centrifugal separation and the second-stage gas-liquid cyclone + gravity sedimentation separation, and separates the gas phase step by step, effectively preventing the gas phase from escaping from the liquid phase outlet, and promoting the gas and liquid outlets to meet the standards at the same time. Through the first-stage gas-liquid separation section, the first gas-liquid separation is achieved under the action of strong centrifugal force to ensure that the first-stage liquid outlet meets the standards; the central exhaust pipe 3 is coaxially arranged vertically with the axial static swirl element 2 and the outer tube 1, which can ensure the stability and separation effect of the gas core to the maximum extent while ensuring the compact structure. On the other hand, the gas core carrying the liquid phase still has a certain cyclone effect after entering the central exhaust pipe 3, which can throw the liquid phase entrained in the gas phase to the inner wall of the central exhaust pipe 3, and enter the annular space of the central exhaust pipe 3 and the outer tube 1 through the circumferentially arranged annular slit 32 for further gravity sedimentation, and the pure gas phase is discharged from the gas phase outlet 7, realizing the second separation of the gas and liquid phases, thereby ensuring that the secondary liquid outlet and the gas phase outlet 7 meet the standards. The synergistic effect of the two gas-liquid separation processes can effectively overcome the problems of the current degassing tubular gas-liquid separator, such as poor separation efficiency, inability to meet the simultaneous gas and liquid outlet standards, and large footprint.

[0044] In the description of this specification, specific features, structures or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0045] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0046] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A two-stage coordinated degassing tubular gas-liquid separator, characterized in that: It comprises an outer tube with a gas-liquid mixture inlet and a gas phase outlet, an axial stationary swirl element located in the outer tube, and a central exhaust pipe, wherein: The outer tube is divided into a primary gas-liquid separation section with a primary liquid phase outlet and a secondary gas-liquid separation section with a secondary liquid phase outlet; the axial static rotating element is located in the primary gas-liquid separation section, and the axial static rotating element includes a central cylinder, on which a rotating blade is arranged, the rotating blade is in a spiral structure, and the outer edge of the rotating blade is tightly fitted with the inner wall of the outer tube; The central exhaust pipe is connected to the primary gas-liquid separation section and the secondary gas-liquid separation section. An annular space exists between the central exhaust pipe and the outer pipe. An annular slit is provided on the outer peripheral wall of the outlet section of the central exhaust pipe. The annular slit is located in the secondary gas-liquid separation section, and the secondary liquid phase outlet is located below the annular slit.

2. The two-stage coordinated degassing tubular gas-liquid separator according to claim 1, characterized in that: The axial stationary rotating element further comprises an end ellipsoidal guide body, which is fixed to the windward end of the central cylinder, and the convex surface of the end ellipsoidal guide body is the windward surface.

3. The two-stage coordinated degassing tubular gas-liquid separator according to claim 2, characterized in that: The axial stationary rotating element further comprises a tail end conical guide body, the tail end conical guide body is fixed to the leeward end of the central cylinder, and the conical end surface of the tail end conical guide body is the leeward surface.

4. The two-stage coordinated degassing tubular gas-liquid separator according to claim 1, characterized in that: The rotating blades are evenly spaced and arranged in the circumferential direction of the central cylinder.

5. The two-stage coordinated degassing tubular gas-liquid separator according to claim 1, characterized in that: The central exhaust pipe comprises an end baffle, a hollow column section and a hollow cone section, wherein: The hollow cone section is fixedly connected to the air inlet end of the hollow column section, the inner diameter of the hollow cone section gradually decreases in the direction away from the hollow column section, the annular slit is located on the peripheral wall of the hollow column section, the end baffle is fixed to the air outlet end of the hollow column section, and the end baffle is provided with an air outlet hole.

6. The two-stage coordinated degassing tubular gas-liquid separator according to claim 5, characterized in that: The annular slits are evenly spaced and arranged on the peripheral wall of the hollow column section.

7. The two-stage coordinated degassing tubular gas-liquid separator according to claim 1, characterized in that: The axial stationary rotating element, the central exhaust pipe and the outer pipe are arranged coaxially.

8. The two-stage coordinated degassing tubular gas-liquid separator according to claim 1, characterized in that: An annular baffle is fixed inside the outer tube, and the inner ring of the annular baffle is fixedly connected to the outer wall of the central exhaust pipe. The area between the gas-liquid mixture inlet and the annular baffle is the primary gas-liquid separation section, and the area between the annular baffle and the gas phase outlet is the secondary gas-liquid separation section.

9. The two-stage coordinated degassing tubular gas-liquid separator according to claim 3, characterized in that: The ratio of the length of the rotating blade to the length of the central cylinder is 0.5-1, the number of the rotating blades is 5-8, and the cone angle range of the tail end conical guide body is 25-60°.

10. The two-stage coordinated degassing tubular gas-liquid separator according to claim 5, characterized in that: The ratio of the diameter of the hollow column section to the diameter of the end baffle is 0.5-0.75, and the cone angle of the hollow cone section is in the range of 3-5°.

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