A high-efficiency oil-gas separation device and method

Abstract

This invention discloses a high-efficiency oil-gas separation device, including a separator body. The separator body is provided with a flow channel and a primary oil outlet. A primary separation mechanism is provided inside the separator body below the flow channel, and a secondary separation mechanism is provided inside the separator body above the flow channel. In this invention, by setting up a two-stage or multi-stage precision separation structure with different filtration accuracies, high-efficiency oil-gas separation is achieved, reducing the probability of gas film formation and improving filtration capacity. The separator body adopts a vertical structure, allowing oil to settle by gravity and accumulate at the bottom, then be discharged from the primary and secondary oil outlets respectively. The two-stage filter element structure adopts a porous media structure with a large specific surface area, strictly controlling the flow velocity of the gas and liquid phases. The lower flow velocity can minimize the occurrence of macroscopic droplet breakage.

Description

Technical Field

[0001] This invention relates to the field of cryogenic vacuum technology, and in particular to a high-efficiency oil-gas separation device and method. Background Technology

[0002] GM refrigerators used in cryogenic pumps require high-purity helium gas with a purity of 99.99% or higher, and the helium gas must be free of oil vapor. If oil vapor is introduced into the refrigerator system, the entire system will be contaminated. Under low-temperature conditions, oil vapor accumulates on the surface of cryogenic components, reducing the heat exchange efficiency of the regenerator, decreasing the cooling capacity, and even preventing the refrigerator from reaching the required cooling temperature, thus rendering the refrigerator inoperable. Furthermore, lubricating oil is essential for oil-lubricated compressors. This necessitates a highly efficient oil separation structure to ensure that clean, high-purity helium gas enters the refrigerator.

[0003] The oil-gas mixture exiting the compressor typically produces oil droplets with diameters ranging from 1 to 50 μm, but a small portion are smaller than 1 μm. Under gravity, as long as the flow rate of the oil-gas mixture isn't too high, the larger oil droplets will eventually fall to the bottom of the oil-gas separator. The smaller the droplet diameter, the longer it takes to fall. However, very small lubricating oil particles can remain suspended in the air for extended periods, unable to be separated from the gas due to their own gravity.

[0004] For different oil droplet sizes, two oil-gas separation methods with different separation mechanisms are usually selected. One is called the mechanical method, which relies on the oil droplets' own gravity or centrifugal force to separate larger oil droplets from the gas. The other is the affinity coalescence method, which uses elements made of special materials to coalesce smaller oil droplets into larger droplets before separating them.

[0005] Helium compressors typically employ both mechanical and affinity coalescence methods for oil-gas separation: mechanical separation for coarse separation and affinity coalescence for fine separation. Current technology generally involves winding single or multiple layers of glass fiber onto a cylindrical structure, using a multi-layered glass fiber layer. However, no structure has yet been found that employs a separate multi-layered, multi-stage structure with a dedicated drainage layer. Since oil droplet sizes mostly span two orders of magnitude between 0.01µm and 1µm, using filter materials of the same specifications in existing technologies is detrimental to filtration efficiency. Even using different specifications between different layers of the same filter element, without gaps, the lack of large droplet settling also hinders filtration. Furthermore, beneficial arrangements and doping of materials with different structural and wetting properties have been implemented. During the doping process, a new mechanism and structure for efficient drainage were discovered, leading to the development of novel, high-efficiency oil-gas separation devices and methods. Summary of the Invention

[0006] The purpose of this invention is to provide a high-efficiency oil-gas separation device and method to solve the above-mentioned problems.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A high-efficiency oil-gas separation device includes a separator body, on which a flow channel and a primary oil outlet are provided. A primary separation mechanism is provided inside the separator body below the flow channel, and a secondary separation mechanism is provided inside the separator body above the flow channel.

[0009] Preferably, the primary separation mechanism includes a primary stainless steel porous cylinder, a primary filter element, and a primary plug. The primary filter element covers the outside of the primary stainless steel porous cylinder, and the primary plug seals the bottom of the primary stainless steel porous cylinder and the primary filter element.

[0010] Preferably, the secondary separation mechanism includes a secondary stainless steel porous cylinder, a secondary filter element, and a secondary plug. The secondary filter element covers the outside of the secondary stainless steel porous cylinder, and the secondary plug seals the top of the secondary stainless steel porous cylinder and the secondary filter element.

[0011] Preferably, both the primary filter element and the secondary filter element include a filtration layer and a drainage layer. The main body of the drainage layer is made of oleophobic fiber material for drainage. Finer and more oleophilic materials are mixed in between the oleophobic fiber materials to introduce the surrounding oil droplets into the drainage layer.

[0012] Preferably, the mesh size of the secondary filter element is smaller than that of the primary filter element, the main body of the filter layer is made of glass fiber, and nanofiber materials are mixed in the glass fiber. Both the primary stainless steel porous cylinder and the secondary stainless steel porous cylinder have hollow structures and several through holes on their outer walls.

[0013] Preferably, one end of the flow channel is connected to an oil and gas inlet, and the other end is connected to a secondary oil outlet. Both the primary and secondary oil outlets are equipped with oil filters. Both the primary and secondary oil outlets are externally connected to capillary tubes, which are designed in a spiral shape.

[0014] Preferably, the separator body has a wool felt at the top inside, a perforated plate at the bottom of the wool felt, and an exhaust port at the top of the separator body.

[0015] Preferably, the separation method of the high-efficiency oil-gas separation device includes the following steps:

[0016] S1. The oil and gas are introduced into the separator body through the oil and gas inlet, and the oil and gas enter the first-stage separation mechanism through the flow channel.

[0017] S2. The oil and gas entering the primary separation unit pass through the primary stainless steel porous cylinder, the primary filter element's filter layer, and the drain layer in sequence. After the oil droplets are filtered, the small oil droplets agglomerate into large oil droplets and then undergo gravity settling after passing through the drain layer, and are finally discharged through the primary oil outlet.

[0018] S3. The remaining oil and gas enter the secondary separation mechanism through the flow channel, and pass through the secondary stainless steel porous cylinder, the secondary filter element filter layer, and the drainage layer in sequence. After the oil droplets are filtered, the small oil droplets are affinity-coagulated into large oil droplets and then undergo gravity sedimentation after passing through the drainage layer, and are finally discharged through the secondary oil outlet.

[0019] S4. The separated gas passes through a perforated plate and wool felt in sequence and is then discharged through the exhaust port.

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0021] 1. The separator body in this application adopts a vertical structure, which allows the oil to settle by gravity and accumulate at the bottom, and be discharged from the primary and secondary oil outlets respectively; the two-stage filter element structure adopts a porous media structure with a large specific surface area, and strictly controls the flow rate of the gas and liquid phases. The flow rate of the general gas and liquid two-phase flow is less than 2m / s. The lower flow rate can minimize the occurrence of macroscopic droplet breakage.

[0022] 2. All oil drain ports in this application are designed with oil filters to ensure that the discharged oil is free of impurities and to prevent oil from clogging the capillary tubes connected to the oil drain ports. The capillary tubes connected to the oil drain ports are designed in a spiral shape to reduce vibration on the one hand and to design appropriate flow resistance on the other hand to ensure smooth oil return while preventing gas from passing through.

[0023] 3. This application sets up a two-stage or multi-stage precision separation structure with different filtration precision for efficient oil-gas separation, reducing the probability of gas film formation and improving filtration capacity. Attached Figure Description

[0024] Figure 1 A schematic diagram of the internal structure of the separator body provided according to an embodiment of the present invention is shown;

[0025] Figure 2 A schematic diagram of the filter layer and drainage layer structure provided according to an embodiment of the present invention is shown;

[0026] Figure 3 A schematic diagram of a capillary structure provided according to an embodiment of the present invention is shown;

[0027] Figure 4 A schematic diagram of an affinity coagulation method provided according to an embodiment of the present invention is shown;

[0028] Figure 5Metallographic images of glass fibers and nanofibers provided according to embodiments of the present invention are shown;

[0029] Figure 6 A comparison diagram of the accuracy of a multi-stage separation mechanism provided according to an embodiment of the present invention is shown;

[0030] Figure 7 The diagram shows the state of oil droplets in oleophobic and oleophilic fibers according to an embodiment of the present invention.

[0031] Legend:

[0032] 1. Flow channel; 2. Primary oil outlet; 3. Primary stainless steel perforated cylinder; 4. Primary filter element; 5. Primary plug; 6. Secondary stainless steel perforated cylinder; 7. Secondary filter element; 8. Secondary plug; 9. Filter layer; 10. Drainage layer; 11. Oil and gas inlet; 12. Secondary oil outlet; 13. Wool felt; 14. Perforated plate; 15. Exhaust port. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The separation target of the fine separation structure in the prior art is the oil-gas mixture after passing through the coarse separator. Small oil droplets account for the majority of the oil-gas mixture. Small oil droplets refer to oil droplets with a diameter of less than 1 μm.

[0035] like Figure 4 As shown, the existing affinity coalescence method is mainly used to separate oil droplets with a diameter of less than 1 μm, and consists of two processes: filtration and coalescence. The element used in this separation method is actually a porous filter material. Before the oil-gas mixture enters the filter element, oil droplets with a diameter larger than the pore size of the element material are filtered out at the surface of the element. Then, by utilizing changes in the shape and size of the internal flow channels of the filter material, small-diameter oil droplets entering the material can coalesce into large-diameter oil droplets on the fibers of the material under the action of various mechanisms (direct collision, inertial interception, and electrostatic adsorption), and are then filtered out. The steps from left to right in the figure are filtration (large oil droplets are blocked), affinity coalescence (small oil droplets coalesce into large oil droplets), and separation (large oil droplets settle).

[0036] After the oil-gas mixture enters the filter element, large droplets larger than the gap between the filter elements will be directly blocked outside the filter element and settle out under the action of inertial force. Small droplets entering the filter element will collide with glass fibers under the action of inertial force and be adsorbed onto the fibers, and then agglomerate into large-diameter droplets. After the large droplets pass through the filter element, they settle on the surface of the filter element, thus achieving separation from the gas. The efficiency of oil-gas separation is related to the state of the oil mist itself, the geometric dimensions of the filter material (thickness of the filter layer, diameter of the fibers, pore size, etc.), and the surface of the filter material.

[0037] Please see Figure 1-7 The present invention provides a technical solution:

[0038] A high-efficiency oil-gas separation device includes a separator body, on which a flow channel 1 and a primary oil outlet 2 are provided. A primary separation mechanism is provided inside the separator body below the flow channel 1, and a secondary separation mechanism is provided inside the separator body above the flow channel 1. The separator body adopts a vertical structure.

[0039] Specifically, such as Figure 1 As shown, the primary separation mechanism consists of a primary stainless steel porous cylinder 3, a primary filter element 4, and a primary plug 5. The primary filter element 4 covers the outside of the primary stainless steel porous cylinder 3, and the primary plug 5 seals the bottom of the primary stainless steel porous cylinder 3 and the primary filter element 4. The secondary separation mechanism consists of a secondary stainless steel porous cylinder 6, a secondary filter element 7, and a secondary plug 8. The secondary filter element 7 covers the outside of the secondary stainless steel porous cylinder 6, and the secondary plug 8 seals the top of the secondary stainless steel porous cylinder 6 and the secondary filter element 7. The main body of the filter element is an ultra-fine glass fiber mesh, constructed in an integrally compacted form, resulting in a stable structure.

[0040] The stainless steel porous cylinder has a stable structure and a porous structure that allows gas to pass through smoothly while providing excellent support for the glass fiber.

[0041] The filter element is sintered at the plug to form stable mechanical dimensions. At the same time, the expansion and locking mechanism at the end compresses the filter element. High-temperature resistant sealant is used to seal the plug and locking mechanism, forming a stable and reliable end sealing structure to prevent oil leakage caused by end seal failure.

[0042] Specifically, such as Figure 1 and Figure 2 As shown, both the primary filter element 4 and the secondary filter element 7 include a filter layer 9 and a drainage layer 10. The main body of the drainage layer 10 is made of oleophobic fiber material for drainage. Finer and more oleophilic materials are mixed in the gaps between the oleophobic fiber materials to introduce the surrounding oil droplets into the drainage layer 10, thereby achieving efficient drainage. The oil droplets coagulate in the oleophilic fibers and settle in the oleophobic fibers.

[0043] Existing technologies employ a single-stage separation mechanism, with the main body made of oleophilic fiber material, which can effectively promote the adsorption and growth of oil droplets by the fibers. However, during the separation stage, this oleophilic property makes it difficult for the droplets to separate and easily forms an oil film, causing some of the oil to revert to small oil droplets.

[0044] The mesh size of the secondary filter element 7 is smaller than that of the primary filter element 4. The main body of the filter layer 9 is made of glass fiber, and nanofiber materials are mixed in the glass fiber. Both the primary stainless steel porous cylinder 3 and the secondary stainless steel porous cylinder 6 are hollow structures and have several through holes on their outer walls.

[0045] Specifically, such as Figure 7 As shown, oil droplets coalesce in oleophilic fibers and settle in oleophobic fibers. In oil-gas separators, smaller filter media fibers more easily adsorb small oil droplets. Mixing nanofiber materials into conventional fiber ratios can significantly increase the total effective oil capture area. It is important to note that the diameter of the nanofiber material used should be significantly different from the diameter of the main filter media fibers; otherwise, it may not achieve the desired effect. Generally, the ratio of the nanofiber diameter to the main filter media fiber diameter is between 1:10 and 1:100.

[0046] Furthermore, nanofibers exhibit a significant electrostatic effect compared to glass fibers. Under airflow disturbance, they generate relative motion with the main glass fibers; this relative motion produces two beneficial effects: first, it generates electrostatics, which enhances the adsorption of oil droplets; second, it disrupts the surface tension between droplets, promoting droplet fusion and growth. Metallographic images of glass fibers and nanofibers are shown below. Figure 5 As shown, the thicker fibers are glass fibers, and the thinner fibers are nanofibers.

[0047] Specifically, such as Figure 1 and Figure 3 As shown, one end of the flow channel 1 is connected to the oil and gas inlet 11, and the other end is connected to the secondary oil outlet 12. Both the primary oil outlet 2 and the secondary oil outlet 12 are designed with oil filters. Both the primary oil outlet 2 and the secondary oil outlet 12 are connected to capillary tubes. The capillary tubes are designed in a spiral shape to reduce vibration on the one hand, and to design appropriate flow resistance on the other hand (specifically by controlling the diameter and length of the capillary tubes) to ensure smooth oil return while preventing gas from passing through.

[0048] The separator body has a wool felt 13 at the top and a perforated plate 14 at the bottom. The top of the separator body is connected to an exhaust port 15.

[0049] A separation method for a high-efficiency oil-gas separator includes the following steps:

[0050] S1. The oil and gas are introduced into the separator body through the oil and gas inlet 11, and the oil and gas enter the first-stage separation mechanism through the flow channel 1.

[0051] S2. The oil and gas entering the primary separation mechanism pass through the primary stainless steel porous cylinder 3, the primary filter element 4, the filter layer 9, and the drain layer 10 in sequence. After the oil droplets are filtered, the small oil droplets are affinity-coagulated into large oil droplets and then undergo gravity sedimentation after passing through the drain layer 10, and are then discharged through the primary oil outlet 2.

[0052] S3. The remaining oil and gas enter the secondary separation mechanism through the flow channel 1, and pass through the filter layer 9 of the secondary stainless steel porous cylinder 6 and the secondary filter element 7 in sequence, and the drain layer 10. After the oil droplets are filtered, the small oil droplets are affinity-coagulated into large oil droplets and then undergo gravity sedimentation after passing through the drain layer 10, and are then discharged through the secondary oil outlet 12.

[0053] S4. The separated gas passes through the perforated plate 14 and the wool felt 13 in sequence and is then discharged through the exhaust port 15.

[0054] The oil-gas separation effect is related to the size of the oil droplets in the separated gas, the mesh diameter of the filter material, the fiber diameter of the filter material, and the thickness of the filter layer.

[0055] During the filtration process, the effectiveness of oil particle coagulation is mainly related to the collision efficiency between oil droplets and the filter element. Obviously, the larger the mesh diameter of the filter media and the smaller the droplets, the lower the collision probability. On the other hand, if the mesh is too small, an air film will form on the mesh. Under the action of pressure difference, the air film will break into small oil droplets, which will also reduce the filtration capacity.

[0056] Therefore, the diameter of the mesh openings must match the size of the oil droplets, such as... Figure 6 As shown, this application employs a two- or multi-stage precision separation structure with different filtration accuracies for efficient oil-gas separation. This reduces the probability of gas film formation and improves filtration capacity.

[0057] It is worth noting that even if there is only one separation mechanism, if this separation mechanism contains two or more such mechanisms... Figure 4 The complete process of filtration, affinity coagulation, and separation shown (i.e., multi-stage) should also be regarded as an extended application of this application.

[0058] The above description of the embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-efficiency oil-gas separation device, comprising a separator body, characterized in that, The separator body is provided with a flow channel (1) and a primary oil outlet (2). The separator body below the flow channel (1) is provided with a primary separation mechanism, and the separator body above the flow channel (1) is provided with a secondary separation mechanism. The primary separation mechanism is provided with a primary stainless steel porous cylinder (3), a primary filter element (4) and a primary plug (5). The primary filter element (4) covers the outside of the primary stainless steel porous cylinder (3), and the primary plug (5) seals the bottom of the primary stainless steel porous cylinder (3) and the primary filter element (4). The secondary separation mechanism is provided with a secondary stainless steel porous cylinder (6), a secondary filter element (7) and a secondary plug (8). The secondary filter element (7) covers the outside of the secondary stainless steel porous cylinder (6), and the secondary plug (8) seals the top of the secondary stainless steel porous cylinder (6) and the secondary filter element (7). Both the primary filter element (4) and the secondary filter element (7) include a filter layer (9) and a drainage layer (10). The main body of the drainage layer (10) is made of oleophobic fiber material for drainage. Finer and more oleophilic materials are mixed in the gaps between the oleophobic fiber materials to introduce the surrounding oil droplets into the drainage layer (10). The mesh size of the secondary filter element (7) is smaller than that of the primary filter element (4). The filter layer (9) is mainly made of glass fiber, and nanofiber material is mixed in the glass fiber. The ratio of the fiber diameter of the nanofiber material to the diameter of the main filter material is between 1:10 and 1:

100. The nanofiber material has a significant electrostatic effect relative to the glass fiber. Under airflow disturbance, the nanofiber material will generate relative movement with the glass fiber. The primary stainless steel porous cylinder (3) and the secondary stainless steel porous cylinder (6) are both hollow structures and have several through holes on their outer walls. One end of the flow channel (1) is connected to an oil and gas inlet (11), and the other end is connected to a secondary oil outlet (12). Both the primary oil outlet (2) and the secondary oil outlet (12) are equipped with oil filters. Both the primary oil outlet (2) and the secondary oil outlet (12) are connected to capillary tubes, which are designed in a spiral shape.

2. The high-efficiency oil-gas separation device according to claim 1, characterized in that, The separator body has a wool felt (13) at the top inside, a perforated plate (14) at the bottom of the wool felt (13), and an exhaust port (15) at the top of the separator body.

3. The separation method of the high-efficiency oil-gas separation device according to claim 2, characterized in that, Includes the following steps: S1. The oil and gas are introduced into the separator body through the oil and gas inlet (11), and the oil and gas enter the first-stage separation mechanism through the flow channel (1); S2. The oil and gas entering the primary separation mechanism pass through the filter layer (9) of the primary stainless steel porous cylinder (3), the primary filter element (4), and the drain layer (10) in sequence. After the oil droplets are filtered, the small oil droplets are affinity-coagulated into large oil droplets and then undergo gravity sedimentation after passing through the drain layer (10), and are then discharged through the primary oil outlet (2). S3. The remaining oil and gas enter the secondary separation mechanism through the flow channel (1), and pass through the filter layer (9) of the secondary stainless steel porous cylinder (6), the secondary filter element (7), and the drain layer (10) in sequence. After the oil droplets are filtered, the small oil droplets are affinity-coagulated into large oil droplets and then undergo gravity sedimentation after passing through the drain layer (10), and are then discharged through the secondary oil outlet (12). S4. The separated gas passes through the perforated plate (14) and wool felt (13) in sequence and is discharged through the exhaust port (15).

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