A dynamic sealing device for a petrochemical flare system

Abstract

The application discloses a dynamic sealing device for a petrochemical flare system. The device comprises a cylinder, a first baffle and a second baffle. The cylinder is used for being installed on the petrochemical flare system; the first baffle is arranged on the inner wall of the cylinder; the second baffle is arranged in the cylinder; and a gas flow channel is defined between the first baffle and the second baffle. Compared with a conventional dynamic sealing device, the occurrence of a nitrogen flow rate peak is moved from the center of the flare to the vicinity of the cylinder wall. At the same nitrogen flow rate, the flow field can be more sufficient to resist the invasion of external air. Therefore, the dynamic sealing device for the petrochemical flare system is safer. Under the condition of keeping the same sealing effect, the dynamic sealing flare head of the annular channel can save the consumption of nitrogen.

Description

Technical Field

[0001] This invention relates to the field of petrochemical equipment, and more specifically to a dynamic sealing device for petrochemical flare systems. Background Technology

[0002] In the prior art, in order to prevent backflow of air into the flare tube when there is no emission or low flow rate in the petrochemical flare system, which could cause backfire or explosion, a sealing device needs to be installed in the petrochemical flare system to seal the flare tube when there is no emission or low flow rate, thereby preventing air from entering.

[0003] The sealing devices include dynamic seals and molecular seals. Dynamic seals ensure that air does not flow back into the flare tube and cause backfire or explosion accidents when there are no emissions or at low flow rates in the petrochemical flare system.

[0004] The molecular seal is a separate device installed between the flare head and the flare tube, and its structure is an inverted bell type. (See reference...) Figure 1 As shown, the working principle is to continuously introduce a purge gas (nitrogen or natural gas) with a molecular weight lighter than air into the inlet. The buoyancy of the purge gas creates a slightly positive pressure area inside the bell jar of the molecular seal, preventing air from entering. The advantage of molecular seals is that a relatively low purge gas flow rate is sufficient to achieve a sealing effect. However, the complexity of its structure results in greater resistance to flare discharge and a larger equipment weight, increasing investment. Summary of the Invention

[0005] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0006] To at least partially solve the above problems, a dynamic sealing device for a petrochemical flare system is provided, characterized in that it comprises:

[0007] A cylindrical body for installation on the petrochemical flare system;

[0008] The first baffle is disposed on the inner wall of the cylinder;

[0009] A second baffle is disposed inside the cylinder;

[0010] A gas flow channel is defined between the first baffle and the second baffle.

[0011] Optionally, the first baffle is a plate that extends upwardly at an angle from the inner wall of the cylinder.

[0012] Optionally, the included angle between the first baffle and the inner wall of the cylinder is between 0 and 90 degrees, and the first baffle is arranged along the circumferential direction of the cylinder.

[0013] Optionally, the second baffle is in an inverted conical structure, and the diameter of the second baffle gradually increases along the gas flow direction.

[0014] Optionally, the axis of the second baffle coincides with the axis of the cylinder.

[0015] Optionally, the included angle of the cross section of the second baffle along the gas flow direction is between 0 and 90 degrees.

[0016] Optionally, the second baffle is fixedly arranged in the cylinder by a support arranged on the inner wall of the cylinder.

[0017] Optionally, the second baffle is one or more.

[0018] Compared with the conventional dynamic sealing device, the occurrence of the nitrogen flow rate peak moves from the torch center to the vicinity of the cylinder wall. At the same nitrogen flow rate, the flow field can be more sufficient to resist the invasion of external air. Therefore, the dynamic sealing device of the application is safer. Under the condition of keeping the same sealing effect, the dynamic sealing torch head of the annular channel can save the consumption of nitrogen. In addition, the dynamic sealing ring is in the form of double baffle plates, which greatly improves the flow area while ensuring the same flow diameter ratio. BRIEF DESCRIPTION OF DRAWINGS

[0019] The following drawings for the present application are hereby incorporated into this application as part of the present application for the purpose of understanding the present application. The embodiments of the present application and their description shown in the drawings are used to explain the device and principles of the present application. In the drawings,

[0020] Figure 1 is a working principle diagram of a molecular seal;

[0021] Figure 2 is a structural schematic diagram of a dynamic sealing device of the prior art;

[0022] Figure 3a is a structural diagram of a dynamic sealing device for a petrochemical torch system provided by an embodiment of the present application;

[0023] Figure 3b is a top view of a dynamic sealing device for a petrochemical torch system provided by an embodiment of the present application;

[0024] Figure 4 is a gas flow direction diagram of a dynamic sealing device for a petrochemical torch system provided by an embodiment of the present application;

[0025] Figure 5Annular flow channel formed for dynamic sealing device for petrochemical flare system.

[0026] Figure 6a Structure diagram of dynamic sealing device without second baffle for d:D = 0.8 in the implementation of the present application;

[0027] Figure 6b Top view of dynamic sealing device without second baffle for d:D = 0.8 in the implementation of the present application;

[0028] Figure 7a Structure diagram of dynamic sealing device with second baffle for d:D = 0.8 in the implementation of the present application;

[0029] Figure 7b Top view of dynamic sealing device with second baffle for d:D = 0.8 in the implementation of the present application;

[0030] Figure 8a Structure diagram of dynamic sealing device without second baffle for d:D = 0.7 in the implementation of the present application;

[0031] Figure 8b Top view of dynamic sealing device without second baffle for d:D = 0.7 in the implementation of the present application;

[0032] Figure 9a Structure diagram of dynamic sealing device with second baffle for d:D = 0.7 in the implementation of the present application;

[0033] Figure 9b Top view of dynamic sealing device with second baffle for d:D = 0.7 in the implementation of the present application. DETAILED DESCRIPTION

[0034] In the following description, numerous specific details are set forth to provide a more thorough understanding of the present application. However, it will be apparent to one of skill in the art that the present application can be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the present application.

[0035] For a thorough understanding of the present application, reference is made to the following detailed description in conjunction with the accompanying drawings. It is to be understood that the application is not limited to the specific details of the preferred embodiments, and that other embodiments can be used and that obvious modifications and equivalents will occur to one of ordinary skill in the art. The following description of the preferred embodiments is provided for the purpose of illustration only.

[0036] Hereinafter, a specific embodiment of the present application will be described in more detail with reference to the accompanying drawings, which show a representative embodiment of the present application and are not intended to limit the present application.

[0037] In the prior art, in the commonly used dynamic sealing technology, when the gas fluid flows slowly from bottom to top in the pipe, the flow rate at the wall is zero due to the effect of fluid viscous force, and the fluid on the central axis is least affected by the pipe wall and has the maximum flow rate. The distribution of the flow field is as shown in Figure 2 , which further causes poor sealing effect at the cylinder wall.

[0038] The commonly used dynamic sealing is to solve the problem of poor sealing effect at the cylinder wall, that is, a circle or several circles of truncated cone baffles are arranged at the wall of the flare head. When the air from the vicinity of the wall penetrates, it immediately changes its flow direction after encountering the baffle, and is discharged with the sweep gas. As shown in Figure 2 , the structure of this kind of dynamic sealing device is very simple, and does not need a separate device. The speed of the sweep gas forms a barrier, and the flow rate of the sweep gas directly affects the safety of the device.

[0039] However, for a long time, in the absence of relevant research, personnel in this field only rely on engineering experience and add a certain safety margin in the selection of sweep speed. Therefore, it leads to a relatively large nitrogen consumption of dynamic sealing.

[0040] After discovering this technical problem, based on the technical problem, one preferred embodiment of the present application provides a dynamic sealing device for a petrochemical flare system. In combination with FIG. 3 and Figure 4 , the present application provides a dynamic sealing device for a petrochemical flare system.

[0041] Referring to Figure 3a and Figure 3b , the device can include a cylinder body 10, a first baffle 20 and a second baffle 30. The cylinder body 10 can be a structure of metal material, such as a cylindrical structure of stainless steel. The cylinder body 10 can be arranged between the petrochemical flare cylinder and the flare head, so that the dynamic sealing device can be located between the petrochemical flare cylinder and the flare head.

[0042] The first baffle 20 can be arranged on the inner wall of the cylinder body 10. For example, the first baffle 20 is a plate extending upwardly inclined to the inner wall of the cylinder body 10, which can be arranged circumferentially along the inner side wall of the cylinder body 10, so that the first baffle 20 is a trapezoidal structure with one end truncated. The included angle between the first baffle 20 and the inner wall of the cylinder body 10 is between 0 degrees and 90 degrees. The dynamic sealing device of the prior art (such as Figure 2The skilled in the art can understand the specific structure, function and setting mode of the first baffle by reading the disclosed materials, and thus the detailed description is omitted here.

[0043] The second baffle 30 can be arranged in the cylinder 10. For example, preferably, the second baffle 30 can be arranged at the middle position of the cylinder 10, that is, when the second baffle 30 is a reverse conical structure, the axis of the second baffle 30 coincides with the axis of the cylinder 10.

[0044] The second baffle 30 can be one or more, and the one or more second baffles 30 can be fixedly arranged in the cylinder 10 by the support 40 arranged on the inner wall of the cylinder 10. For example, the support 40 can be a section steel, and a plurality of section steels can be arranged at equal intervals on the side wall of the cylinder 10, and the plurality of section steels extend upwardly and obliquely, thereby jointly fixing the second baffle 30 at a predetermined position in the cylinder 10, so that the second baffle 30 can be more stably fixed in the cylinder 10. When the second baffle 30 is a reverse conical structure, the included angle of the cross section of the second baffle 30 along the gas flow direction is between 0 degree and 90 degrees.

[0045] The application provides a dynamic sealing device for a petrochemical torch system, which can be arranged in the cylinder 10, for example, a circle of reverse conical second baffles 30 (as shown in Figure 3a ) on the central axis of the cylinder 10, thereby forming an annular channel (as shown in Figure 5 the shadow area of the top view). The dynamic sealing ring of the annular channel is arranged to make the peak value of the nitrogen flow rate close to the cylinder wall (as shown in Figure 4 ), and the cylinder wall is the part where the air is most likely to invade. Compared with the conventional dynamic sealing device, the appearance of the peak value of the nitrogen flow rate moves from the center of the torch to the vicinity of the cylinder wall, so that the flow rate of the gas at the cylinder wall is relatively large. Under the same nitrogen flow rate, the flow field can be more sufficient to resist the invasion of external air. Therefore, the sealing effect of the dynamic sealing device of the application is better, and it is safer.

[0046] Meanwhile, under the condition of keeping the same sealing effect, the dynamic sealing torch head of the annular channel can save the consumption of nitrogen. The dynamic sealing ring is in the form of double baffles, which greatly improves the flow area while ensuring the same flow diameter ratio. For example, taking a DN1000 torch as an example, when d:D=0.8 (as shown in Figure 6a ), wherein d represents the diameter of the fluid flow of the gas, and D represents the diameter of the annular channel (cylinder 10). Referring to Figure 6a and 6b , wherein Figure 6b is a top view of the dynamic sealing device without the second baffle 30 in the prior art and shows the fluid flow area. Continue to refer to Figure 7aand 7b As shown, Figure 7b This is a top view of a dynamic sealing device equipped with a second baffle, showing the fluid flow area. Due to the presence of the second baffle 30, taking nitrogen as an example, the peak flow velocity of nitrogen will move closer to the cylinder wall, narrowing the distance between the side wall of the cylinder and the peak velocity. Figure 7a The width of the first baffle 20 in the middle can be set compared to Figure 6a The smaller size allows for a larger fluid flow area, enabling the annular channel dynamic sealing device to increase the fluid flow area by 25% compared to currently used dynamic sealing devices. In another embodiment, referring to... Figure 8a and 8b as well as Figure 9a and 9b As shown, when d:D = 0.7, the flow area increases by 43%, thereby reducing the resistance of the gas in the flare during exhaust. Simultaneously, at the same nitrogen flow rate, the sealing effect is better, thus improving the sealing performance.

[0047] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for descriptive purposes only and is not intended to limit the invention. Terms such as “part” or “component” appearing herein can refer to a single part or a combination of multiple parts. Terms such as “installation” or “installation” appearing herein can refer to one component being directly attached to another component or one component being attached to another component via an intermediary. A feature described in one embodiment herein may be applied, alone or in combination with other features, to another embodiment, unless that feature is not applicable in that other embodiment or is otherwise stated.

[0048] The present invention has been described through the above embodiments. However, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit the present invention to the described embodiments. Furthermore, those skilled in the art will understand that the present invention is not limited to the above embodiments, and many variations and modifications can be made based on the teachings of the present invention, all of which fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A dynamic sealing device for a petrochemical flare system, characterized in that, The utility model relates to a flare gas recovery device for petrochemical flare system, comprising: a cylinder body for being installed on the petrochemical flare system; a first baffle arranged on the inner wall of the cylinder body; a second baffle arranged in the cylinder body, the second baffle is inverted conical structure, the diameter of the second baffle gradually increases along the gas flow direction, and the second baffle is fixedly arranged in the cylinder body through the support arranged on the inner wall of the cylinder body; a gas flow channel is defined between the first baffle and the second baffle; d:D is 0.7 or 0.8, wherein d represents the diameter of the fluid flow of the gas, and D represents the diameter of the cylinder body.

2. The dynamic sealing device of a petrochemical flare system according to claim 1, characterized in that, The first baffle is a plate that extends upwardly and obliquely from the inner wall of the cylinder body.

3. The dynamic sealing device of a petrochemical flare system according to claim 2, characterized in that, The included angle between the first baffle and the inner wall of the cylinder body is between 0 degrees and 90 degrees, and the first baffle is arranged along the circumferential direction of the cylinder body.

4. The dynamic sealing device of a petrochemical flare system of claim 1, wherein, The axis of the second baffle coincides with the axis of the cylinder body.

5. The dynamic sealing device of a petrochemical flare system according to any one of claims 1 to 4, characterized in that, The included angle of the cross section of the second baffle along the gas flow direction is between 0 degrees and 90 degrees.

6. The dynamic sealing device of a petrochemical flare system of claim 1, wherein, The second baffle is one or more.

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