Natural gas freezing water removal device

Abstract

The utility model relates to a natural gas freezing dewatering device which comprises a vertical dewatering tower, a cooling liquid tank, a circulating pump, a heat exchanger and an air-cooled refrigerator, in the vertical dehydration tower, the wet natural gas moves upwards, the cooled washing liquid flushes downwards, and the washing liquid carrying impurities in the wet natural gas enters a cooling liquid tank; the wet natural gas is discharged after water mist is continuously removed upwards; the washing liquid carrying impurities is sequentially settled in the cooling liquid tank, heavy components, liquid-phase components and light components are respectively discharged, and the liquid-phase components are driven by the circulating pump to enter the heat exchanger for heat exchange and then return to the vertical dehydration tower to form a countercurrent washing circulation loop; the heat exchanger is connected with the air-cooled refrigerator to form a refrigeration circulation loop. According to the utility model, a countercurrent washing circulation loop is adopted, settling separation is realized in the cooling liquid tank through uninterrupted water flow taking-out, and the defect of easy blockage in a conventional coalescence filtering method is avoided. Natural cold energy is input through the air-cooled refrigerator, and the heat transfer efficiency in the heat exchange process is improved.

Description

Technical Field

[0001] The utility model belongs to the field of oil and gas field equipment, and in particular relates to a natural gas freezing and water removal device. Background Art

[0002] Natural gas from natural gas wells is called wet natural gas because it contains a small amount of condensate oil, condensate and saturated water vapor. Wet natural gas has a high liquid holdup. In addition to a large amount of free water, untreated wet natural gas also contains a part of hydrocarbon components (ethane mass fraction 6% to 10%). During transportation, when the temperature in the pipeline is lower than the hydrate formation temperature, hydrocarbon components and free water are likely to form hydrates, leading to pipeline blockage, affecting pipeline safety, and causing economic waste and losses. Therefore, wet natural gas needs to be dehydrated before pipeline transportation.

[0003] Conventional water removal treatment uses a collision coalescence filtration method. The operating temperature of this method is generally high, and additional water cooling or air cooling is required for natural gas heat exchange and cooling. Because gas is a poor conductor of heat, has a low heat capacity and a large thermal resistance, and is prone to form an adhesion layer on the surface of the heat exchange tube due to condensation adsorption, the heat transfer efficiency of the heat exchange tube to the natural gas is low, the actual cooling effect is poor, and the loss of refrigeration power is large. The interface of the condensate is also a corrosion-prone area, and stress concentration is prone to occur at the corrosion location, which leads to premature damage to the equipment and increases safety risks. During the working process of coalescence filtration, the filter material will gradually become saturated and block the filter equipment, resulting in degradation of working conditions, and the filter equipment needs to be replaced regularly; the auxiliary rotary liquid separation effect is closely related to the air flow velocity. If the air flow velocity is too small, the liquid separation will fail. If the air flow velocity is too large, it will also cause the natural gas to break through the fog capture layer and be carried out. Therefore, in order to improve the water removal effect, a natural gas freezing water removal device is needed. Utility Model Content

[0004] In order to solve the above problems existing in the prior art, the utility model provides a natural gas freezing and water removal device. The technical problem to be solved by the utility model is achieved through the following technical solutions:

[0005] The utility model provides a natural gas freezing and dehydration device, comprising: a vertical dehydration tower, a coolant tank, a circulation pump, a heat exchanger and an air-cooling refrigerator;

[0006] The vertical dehydration tower comprises: a washing filling area, a demisting filling area, a total feed inlet, a clean gas outlet, a cooling liquid inlet and a washing liquid outlet;

[0007] The demisting packing area is arranged above the washing packing area, the main feed port is arranged below the washing packing area, the clean gas outlet is located above the demisting packing area, the cooling liquid inlet is located between the washing packing area and the demisting packing area, and the washing liquid outlet is arranged at the bottom of the vertical dehydration tower;

[0008] Wet natural gas enters from the main feed port and passes upward through the washing packing area; cooled washing liquid enters from the cooling liquid inlet, washes the wet natural gas downward, and then the washing liquid carrying impurities in the wet natural gas enters the cooling liquid tank from the washing liquid outlet; the washed wet natural gas passes upward through the demisting packing area and is discharged from the clean gas outlet;

[0009] The washing liquid carrying impurities in the wet natural gas is sequentially precipitated and separated into heavy components, liquid components and light components in the cooling liquid tank and discharged respectively, wherein the liquid components are driven upward by the circulation pump to the heat exchanger for heat exchange, and the liquid components after heat exchange enter the vertical dehydration tower from the washing liquid outlet to form a countercurrent washing circulation loop;

[0010] The heat exchanger is connected to the air-cooling refrigerator to form a refrigeration cycle.

[0011] In one embodiment of the utility model, the vertical dehydration tower further comprises: an overpressure relief port;

[0012] The overpressure relief port is arranged at the top of the vertical dehydration tower and is connected to the station area venting torch for overpressure relief.

[0013] In one embodiment of the utility model, the washing filler is filled in the washing filler area, the washing filler is a ball ring filler, and the filling height of the washing filler is 2 to 4 times the inner diameter of the washing filler area.

[0014] In one embodiment of the present invention, the demisting filler area is filled with a demisting filler, and the demisting filler is a 250Y structured filler.

[0015] In one embodiment of the utility model, the vertical dehydration tower is connected to the cooling liquid tank through a gas phase communication port, and the diameter of the gas phase communication port is 0.3 to 0.6 times the diameter of the washing liquid outlet.

[0016] In one embodiment of the present invention, the diameter of the washing liquid outlet is 3 to 6 times the diameter of the cooling liquid inlet.

[0017] In one embodiment of the utility model, the coolant tank comprises: a middle partition and a high partition;

[0018] The middle partition is arranged near the washing liquid inlet, and the middle partition and the high partition divide the cooling liquid tank into three equal-length areas, which are the sewage discharge area, the cooling liquid area and the light area in sequence;

[0019] The heavy components are discharged from the sewage outlet arranged at the bottom of the sewage discharge area;

[0020] The coolant area is located between the middle baffle and the high baffle, and the liquid phase component is discharged from a coolant outlet arranged at the bottom of the coolant area, and the coolant outlet is connected to the circulation pump;

[0021] The light component is discharged from a drain port arranged at the bottom of the light oil area.

[0022] In one embodiment of the present invention, the height of the middle partition is half of the inner diameter of the coolant tank.

[0023] In one embodiment of the present invention, the height of the high-position partition is two-thirds of the inner diameter of the coolant tank.

[0024] In one embodiment of the utility model, the heat exchanger adopts an internal floating head heat exchanger or a U-tube heat exchanger with free expansion space, and the liquid phase components to be heat exchanged enter from the bottom of the heat exchanger, and the liquid phase components after heat exchange flow out from the top.

[0025] Compared with the prior art, the beneficial effects of the utility model are:

[0026] The utility model of the natural gas freezing and dehydration device adopts a countercurrent washing circulation loop, uses cooling washing liquid to wash and absorb water and impurities such as light hydrocarbons, hydrogen sulfide, carbon dioxide and micro-particles in the natural gas, and takes them out through uninterrupted water flow, and achieves sedimentation separation in the cooling liquid tank, avoiding the easy clogging disadvantage of conventional coalescence and filtration methods, and realizes instant internal renewal. The cold energy of nature is input through an air-cooled refrigerator, and the heat transfer efficiency of the heat exchange process is improved through liquid-liquid heat exchange, which also improves the freezing and dehydration effect of natural gas.

[0027] The utility model of natural gas freezing and dehydration device forms a local low temperature zone at the upper part of the vertical dehydration tower by circulating and cooling the washing liquid, simulating the cloud-making and rain-making process in nature, and promoting the spontaneous condensation and agglomeration of impurities entrained in the wet natural gas through strong cold absorption. In the cooling liquid tank, the washing liquid after washing is subjected to three-stage sedimentation separation, and the heavy components are discharged immediately. The main component of the liquid phase is water, which is absorbed after self-circulation cooling. The light component phase on the upper layer is rich in hydrocarbon light oil and is discharged and recovered separately. Each component is treated separately to meet environmental protection requirements.

[0028] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a natural gas freezing and water removal device provided in an embodiment of the utility model.

[0030] Icons: 10-vertical dehydration tower; 11-washing packing area; 12-demist packing area; 13-main feed inlet; 14-overpressure relief port; 15-clean gas outlet; 16-cooling liquid inlet; 17-gas phase connection port; 18-washing liquid outlet; 20-cooling liquid tank; 21-middle partition; 22-high partition; 23-washing liquid inlet; 24-sewage outlet; 25-cooling liquid outlet; 26-drain port; 27-liquid level meter; 30-circulating pump; 40-heat exchanger; 50-air-cooled refrigerator. DETAILED DESCRIPTION

[0031] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the present invention, a natural gas freezing and water removal device proposed according to the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0032] The above and other technical contents, features and effects of the utility model are clearly presented in the following detailed description of the specific implementation mode in conjunction with the accompanying drawings. Through the description of the specific implementation mode, the technical means and effects adopted by the utility model to achieve the predetermined purpose can be more deeply and specifically understood. However, the attached drawings are only for reference and explanation, and are not used to limit the technical solution of the utility model.

[0033] Embodiment 1

[0034] See also Figure 1 The natural gas freezing and dehydration device of this embodiment includes: a vertical dehydration tower 10, a cooling liquid tank 20, a circulating pump 30, a heat exchanger 40 and an air-cooled refrigerator 50. The wet natural gas enters the vertical dehydration tower 10 and moves from bottom to top for dehydration. After the washing liquid is cooled in the heat exchanger 40, it washes the wet natural gas in the vertical dehydration tower 10 from top to bottom, washing and absorbing the water and impurities such as light hydrocarbons, hydrogen sulfide, carbon dioxide and micro-particulate matter in the wet natural gas. The washing liquid carrying impurities enters the cooling liquid tank 20 to settle and separate in turn. The separated cooling liquid is driven by the circulating pump 30 and returns to the vertical dehydration tower 10 through the heat exchanger 40 to form a countercurrent washing circulation loop. The heat exchanger 40 is connected to the air-cooled refrigerator 50 to form a refrigeration circulation loop.

[0035] In this embodiment, the vertical dehydration tower 10 includes: a washing packing area 11, a demisting packing area 12, a total feed inlet 13, a clean gas outlet 15, a cooling liquid inlet 16 and a washing liquid outlet 18; the demisting packing area 12 is arranged above the washing packing area 11, the total feed inlet 13 is arranged below the washing packing area 11, the clean gas outlet 15 is located above the demisting packing area 12, the cooling liquid inlet 16 is located between the washing packing area 11 and the demisting packing area 12, and the washing liquid outlet 18 is arranged at the bottom of the vertical dehydration tower 10.

[0036] In this embodiment, wet natural gas enters from the main feed port 13 and passes upward through the washing packing area 11; cooled washing liquid enters from the cooling liquid inlet 16, and after flushing the wet natural gas downward, the washing liquid carrying impurities in the wet natural gas enters the cooling liquid tank 20 from the washing liquid outlet 18; the washed wet natural gas passes upward through the demisting packing area 12 and is discharged from the clean gas outlet 15; the washing liquid carrying impurities in the wet natural gas is sequentially precipitated and separated into heavy components, liquid components and light components in the cooling liquid tank 20 and discharged separately, wherein the liquid components are driven upward by the circulating pump 30 to the heat exchanger 40 for heat exchange, and the liquid components after heat exchange enter the vertical dehydration tower 10 from the washing liquid outlet 18, forming a countercurrent washing circulation loop.

[0037] In an optional embodiment, the vertical dehydration tower 10 further includes: an overpressure relief port 14; the overpressure relief port 14 is arranged at the top of the vertical dehydration tower 10 and connected to the venting torch in the dehydration area for overpressure relief. Furthermore, a safety valve is arranged at the overpressure relief port 14, and the overpressure natural gas enters the dehydration torch in the dehydration area through the relief port and the pipeline for combustion and discharge, thereby providing overpressure safety protection for the entire equipment.

[0038] In this embodiment, a washing filler is filled in the washing filler area 11. Preferably, the washing filler is a ball ring filler, which has the advantage of being not easily blocked, and the filling height of the washing filler is 2 to 4 times the inner diameter of the washing filler area 11. A maintenance manhole is also provided on the filler for easy maintenance and observation.

[0039] In this embodiment, the demisting filler is filled in the demisting filler area 12. Preferably, the demisting filler is 250Y structured filler, the filling joints are dense, the upper part of the filler is pressed tightly to prevent blowing off, and an inspection manhole is set on the filler.

[0040] In an optional embodiment, the vertical dehydration tower 10 and the cooling liquid tank 20 are connected through the gas phase communication port 17 to form a communicating vessel, which is conducive to the discharge and flow of the washing liquid. Preferably, the diameter of the gas phase communication port 17 is 0.3 to 0.6 times the diameter of the washing liquid outlet 18.

[0041] In an optional embodiment, the diameter of the washing liquid outlet 18 is 3 to 6 times the diameter of the cooling liquid inlet 16 .

[0042] In this embodiment, the cooling liquid tank 20 includes: a middle partition 21 and a high partition 22; the middle partition 21 is arranged near the washing liquid inlet 23, and the middle partition 21 and the high partition 22 divide the cooling liquid tank 20 into three equal-length areas, namely, the sewage discharge area, the cooling liquid area and the light area, wherein the cooling liquid area is located between the middle partition 21 and the high partition 22. The washing liquid carrying impurities in the wet natural gas is precipitated and separated in the sewage discharge area, the cooling liquid area and the light area in the cooling liquid tank 20, and the heavy components, the liquid components and the light components are also discharged from the outlets arranged in the respective areas.

[0043] Specifically, the heavy components are discharged from the sewage outlet 24 arranged at the bottom of the sewage area; the liquid components are discharged from the coolant outlet 25 arranged at the bottom of the coolant area, and the coolant outlet 25 is connected to the circulation pump 30; the light components are discharged from the drainage port 26 arranged at the bottom of the light oil area.

[0044] In an optional embodiment, the height of the middle partition 21 is half of the inner diameter of the coolant tank 20, and the height of the high partition 22 is two-thirds of the inner diameter of the coolant tank 20, and the bottom of the middle partition 21 and the high partition 22 connected to the coolant tank 20 is ensured to be tight.

[0045] In an optional embodiment, a liquid level meter 27 is further provided at the rear of the coolant tank 20 for detecting the liquid level height of the light area.

[0046] Preferably, the heat exchanger 40 adopts an internal floating head heat exchanger or a U-tube heat exchanger with free expansion space, and the liquid phase components to be heat exchanged enter from the bottom of the heat exchanger 40, and the liquid phase components after heat exchange flow out from the top, so that the liquid phase components to be heat exchanged can fully saturate the heat exchange area inside the heat exchanger 40. Specifically, inside the heat exchanger 40, the circulating liquid flows through the shell side, and the refrigerated liquid flows through the tube side to avoid ice formation in the heat exchange tubes and affect the operation of the heat exchanger 40.

[0047] It is worth noting that the air-cooled refrigerator 50 can adapt to the harsh natural environment of the desert Gobi, avoid water freezing and frostbite and dust blockage, thereby improving the efficiency and reliability of the natural gas cooling and water removal device.

[0048] In the specific use process, the wet natural gas enters from the main feed port 13, passes upward through the washing packing area 11, and quickly reduces the kinetic energy. The heavy component impurities therein first fall or are adsorbed on the washing packing. The cooling washing liquid enters the washing liquid from the cooling liquid inlet 16, and contacts the wet natural gas in the reverse direction, so that the wet natural gas is fully cooled, and the water and light components such as light hydrocarbons entrained therein are fully condensed and absorbed, and fall with the washing liquid. The washing liquid continues to wash the washing packing area 11 and the bottom of the vertical dehydration tower 10 downward, so that the heavy components also enter the cooling liquid tank 20 with the washing liquid from the washing liquid outlet 18. On the contrary, the washed wet natural gas continues to move upward in the vertical dehydration tower 10, passes through the demisting packing area 12 to further remove the water mist, becomes clean gas, and is discharged from the clean gas outlet 15. Since the flow direction of the wet natural gas and the washing liquid is opposite, it is called countercurrent washing. The washing liquid carrying impurities in the wet natural gas settles in the coolant tank 20 in sequence, achieving three-stage separation, and correspondingly, is separated into heavy components, liquid components and light components according to the gradually decreasing density. The heavy components settle first and are blocked by the middle partition 21 and remain in the sewage discharge area. The liquid components continue to move to the coolant area between the middle partition 21 and the high partition 22. The light components are the lightest and reach the light area. Among them, the heavy components are discharged from the sewage discharge outlet 24, the liquid components are discharged from the coolant outlet 25, and the light components are discharged from the liquid discharge outlet 26.

[0049] Furthermore, the liquid phase components are driven upward by the circulation pump 30 to the heat exchanger 40 for heat exchange, and the liquid in the heat exchanger 40 is cooled by the air-cooled refrigerator 50, forming a refrigeration cycle. The cooled liquid phase components enter the vertical dehydration tower 10 again through the washing liquid outlet 18 as a new cooling washing liquid, so that the wet natural gas is washed by the cooling washing liquid, and then precipitated and separated and then circulated and cooled, forming a countercurrent washing cycle. After the cycle is established, as the washing liquid continuously washes and removes impurities, blockage can be avoided, and the steps of replacing the filter element of conventional coalescence filtration can be eliminated, achieving instant internal renewal, improving the dewatering quality, and saving operating costs.

[0050] The utility model of the natural gas freezing and dehydration device adopts a countercurrent washing circulation loop, uses cooling washing liquid to wash and absorb water and impurities such as light hydrocarbons, hydrogen sulfide, carbon dioxide and micro-particles in the natural gas, and takes them out through uninterrupted water flow, and achieves sedimentation separation in the cooling liquid tank, avoiding the easy clogging disadvantage of conventional coalescence and filtration methods, and realizes instant internal renewal. The cold energy of nature is input through an air-cooled refrigerator, and the heat transfer efficiency of the heat exchange process is improved through liquid-liquid heat exchange, which also improves the freezing and dehydration effect of natural gas.

[0051] The utility model of natural gas freezing and dehydration device forms a local low temperature zone at the upper part of the vertical dehydration tower by circulating and cooling the washing liquid, simulating the cloud-making and rain-making process in nature, and promoting the spontaneous condensation and agglomeration of impurities entrained in the wet natural gas through strong cold absorption. In the cooling liquid tank, the washing liquid after washing is subjected to three-stage sedimentation separation, and the heavy components are discharged immediately. The main component of the liquid phase is water, which is absorbed after self-circulation cooling. The light component phase on the upper layer is rich in hydrocarbon light oil and is discharged and recovered separately. Each component is treated separately to meet environmental protection requirements.

[0052] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant is intended to cover non-exclusive inclusion, so that the article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the article or device including the elements. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The orientation or position relationship indicated by "up", "down", "left", "right", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the utility model 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 a limitation to the utility model.

[0053] The above contents are further detailed descriptions of the present invention in combination with specific preferred implementations, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A natural gas freezing and dehydration device, characterized in that: include: A vertical dehydration tower (10), a cooling liquid tank (20), a circulating pump (30), a heat exchanger (40) and an air-cooling refrigerator (50); The vertical dehydration tower (10) comprises: a washing filling area (11), a demisting filling area (12), a main feed inlet (13), a clean gas outlet (15), a cooling liquid inlet (16) and a washing liquid outlet (18); The demisting packing area (12) is arranged above the washing packing area (11), the main feed port (13) is arranged below the washing packing area (11), the clean gas outlet (15) is located above the demisting packing area (12), the cooling liquid inlet (16) is located between the washing packing area (11) and the demisting packing area (12), and the washing liquid outlet (18) is arranged at the bottom of the vertical dehydration tower (10); Wet natural gas enters from the main feed inlet (13) and passes upward through the washing packing area (11); cooled washing liquid enters from the cooling liquid inlet (16), washes the wet natural gas downward, and then the washing liquid carrying impurities in the wet natural gas enters the cooling liquid tank (20) from the washing liquid outlet (18); the washed wet natural gas passes upward through the demisting packing area (12) and is discharged from the clean gas outlet (15); The washing liquid carrying impurities in the wet natural gas is sequentially precipitated and separated into heavy components, liquid components and light components in the cooling liquid tank (20) and discharged respectively, wherein the liquid components are driven upward by the circulation pump (30) to the heat exchanger (40) for heat exchange, and the liquid components after heat exchange enter the vertical dehydration tower (10) through the washing liquid outlet (18), forming a countercurrent washing circulation loop; The heat exchanger (40) is connected to the air-cooling refrigerator (50) to form a refrigeration cycle.

2. The natural gas freezing and dehydration device according to claim 1, characterized in that: The vertical dehydration tower (10) further comprises: an overpressure relief port (14); The overpressure relief port (14) is arranged at the top of the vertical dehydration tower (10) and is connected to the station area venting torch for overpressure relief.

3. The natural gas freezing and dehydration device according to claim 1, characterized in that: The washing filler area (11) is filled with a washing filler, which is a ball ring filler. The filling height of the washing filler is 2 to 4 times the inner diameter of the washing filler area (11).

4. The natural gas freezing and dehydration device according to claim 1, characterized in that: The demisting filler area (12) is filled with a demisting filler, and the demisting filler is a 250Y structured filler.

5. The natural gas freezing and dehydration device according to claim 1, characterized in that: The vertical dehydration tower (10) is connected to the cooling liquid tank (20) via a gas phase communication port (17), and the diameter of the gas phase communication port (17) is 0.3 to 0.6 times the diameter of the washing liquid outlet (18).

6. The natural gas freezing and dehydration device according to claim 1, characterized in that: The diameter of the washing liquid outlet (18) is 3 to 6 times the diameter of the cooling liquid inlet (16).

7. The natural gas freezing and dehydration device according to claim 1, characterized in that: The cooling liquid tank (20) comprises: a middle partition (21) and a high partition (22); The middle partition (21) is arranged near the washing liquid inlet (23), and the middle partition (21) and the high partition (22) divide the cooling liquid tank (20) into three equal-length areas, which are the sewage discharge area, the cooling liquid area and the light area in sequence; The heavy components are discharged from a sewage outlet (24) arranged at the bottom of the sewage discharge area; The coolant region is located between the middle baffle (21) and the high baffle (22), and the liquid phase component is discharged from a coolant outlet (25) arranged at the bottom of the coolant region, and the coolant outlet (25) is connected to the circulation pump (30); The light component is discharged from a drain port (26) arranged at the bottom of the light area.

8. The natural gas freezing and dehydration device according to claim 7, characterized in that: The height of the middle partition (21) is half of the inner diameter of the coolant tank (20).

9. The natural gas freezing and dehydration device according to claim 7, characterized in that: The height of the high-position partition (22) is two-thirds of the inner diameter of the coolant tank (20).

10. The natural gas freezing and dehydration device according to claim 1, characterized in that: The heat exchanger (40) is an internal floating head heat exchanger or a U-tube heat exchanger with a free expansion space. The liquid phase components to be heat exchanged enter from the bottom of the heat exchanger (40), and the liquid phase components after heat exchange flow out from the top.

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