Natural gas recovery device, natural gas purification system and fuel gas pipeline network

Abstract

The utility model relates to natural gas purification field, concretely relates to a natural gas recovery device, natural gas purification system and fuel gas pipe network, wherein recovery device includes the drainage tube, the drainage tube is used to communicate natural gas purification system and fuel gas pipe network, is equipped with the closing assembly and the angle valve on the drainage tube, wherein: the closing assembly is used for realizing the cut-off or seal of drainage tube, the angle valve is used for adjusting the pressure of fuel gas that drainage tube is delivered to fuel gas pipe network. The utility model realizes the recovery of residual natural gas in natural gas purification system during the shutdown of natural gas purification system, avoids causing the waste of natural gas, seals the drainage tube through the closing assembly during the normal work of natural gas purification system, avoids the high pressure gas from leaking to fuel gas pipe network, ensures the normal operation of natural gas purification system.

Description

Technical Field

[0001] This utility model relates to the field of natural gas purification, and in particular to a natural gas recovery device, a natural gas purification system, and a fuel gas pipeline network. Background Technology

[0002] After existing natural gas purification units are shut down, a large amount of fuel gas remains in the system. To ensure the safety and reliability of the shutdown process, nitrogen replacement is usually used to replace the fuel gas with fuel gas for combustion in the flare system, ensuring that the system is in an inert gas environment and providing safety assurance for subsequent shutdown and maintenance. However, this operation method results in the loss of fuel gas.

[0003] Therefore, a technical solution is needed to address the problem that a large amount of residual fuel gas in the system after the natural gas purification unit is shut down, which would result in fuel gas waste if directly discharged into the flare system for combustion. Utility Model Content

[0004] The purpose of this invention is to overcome the technical problem that a large amount of fuel gas remains in the system after the natural gas purification device is shut down, and that direct discharge into the flare system for combustion will cause fuel gas waste. This invention provides a natural gas recovery device, a natural gas system, and a fuel gas pipeline network.

[0005] In a first aspect, the present invention provides a natural gas recovery device, including a diversion pipe for connecting a natural gas purification system and a fuel gas pipeline network, wherein the diversion pipe is equipped with a shut-off component and an angle valve, wherein: The shut-off component is used to cut off or seal the drainage tube; The angle valve is used to regulate the pressure of the fuel gas delivered from the drain pipe to the fuel gas pipeline network.

[0006] This utility model discloses a natural gas recovery device. In use, the two ends of the inlet pipe are connected to a natural gas purification system and a fuel gas pipeline, respectively. During normal operation of the natural gas purification system, the inlet pipe is sealed by a shut-off component to prevent high-pressure gas from leaking into the fuel gas pipeline. During the shutdown of the natural gas purification system, the shut-off component is opened, and the residual natural gas at 5.8 MPa in the natural gas purification system is transported to the fuel gas pipeline after the pressure is reduced by an angle valve. The pressure is maintained until the pressure of the natural gas purification system is reduced to 0.4 MPa, which is equal to the pressure of the fuel gas pipeline. Then, the shut-off component and the angle valve are closed. The remaining natural gas in the natural gas purification system is replaced by nitrogen and burned in the flare system for emission.

[0007] Preferably, the shut-off component includes a first valve and a second valve, both of which can cut off or seal the drainage tube.

[0008] The shut-off assembly uses the first and second valves to control the diversion pipe, providing double protection for the sealing of the diversion pipe and reducing the probability of natural gas leaking from the purification system into the fuel gas pipeline during the purification process.

[0009] Preferably, the first valve is a gate valve and the second valve is a stop valve.

[0010] Both the gate valve used in the first valve and the stop valve used in the second valve can cut off or seal the drain pipe. However, they are different types of valves. Under the same working conditions, the probability of them failing together is smaller, which improves the safety of the shut-off component sealing the drain pipe.

[0011] Preferably, the drainage tube is provided with two pressure gauges, and the angle valve is located between the two pressure gauges.

[0012] Two pressure gauges monitor the pressure inside the drainage tube and before and after the angle valve, respectively, serving as overpressure protection and leakage monitoring.

[0013] Preferably, a one-way valve is provided on the drain pipe, and the one-way valve is located between the angle valve and the fuel gas pipeline.

[0014] To prevent natural gas in the fuel gas pipeline from flowing back into the purification system during the later stages of exhaust.

[0015] Preferably, a branch pipe platform is provided at one end of the diversion pipe that connects to the natural gas purification system.

[0016] A branch pipe assembly is a key component used to connect branch pipes to the main pipeline. It is mainly used for flow distribution in diversion or convergence pipeline systems. It can be fixed to the main pipeline by welding, threaded connection, or other methods. In natural gas purification systems, the pipeline diameter is large, while the diversion pipe diameter is small. By connecting the diversion pipe to the pipeline in the natural gas purification system through the branch pipe assembly, there is no need to cut or modify the main pipe as a whole, thereby reducing installation complexity and cost issues.

[0017] Preferably, the end of the drain pipe that connects to the fuel gas pipeline is provided with a tee.

[0018] The pipes in the fuel gas pipeline network have a small diameter, making it unsuitable for drilling holes to install branch pipe platforms. Instead, the smaller pipes can be directly cut and installed with tees, which simplifies the process and reduces the difficulty of connecting the drain pipe to the fuel gas pipeline network.

[0019] Preferably, the drainage tube includes a first pipe section and a second pipe section that are interconnected, and the angle valve is located at the end where the first pipe section connects to the second pipe section. The first pipe section is a stainless steel structural component, and the second pipe section is a carbon steel structural component.

[0020] In the drainage pipe: the section between the angle valve and the natural gas purification system is the first pipe section, which needs to withstand a gas pressure of 5.8MPa. Therefore, it is made of stainless steel to improve the pressure-bearing capacity of the first pipe section and ensure the safety of the drainage pipe during use; the section between the angle valve and the fuel gas pipeline is the second pipe section, which needs to withstand a gas pressure of 0.4MPa. Therefore, carbon steel structural components are selected, which can meet the strength requirements under low-pressure conditions and are more economical.

[0021] In a second aspect, the present invention provides a natural gas purification system, comprising a natural gas desulfurization tower, a desulfurized gas separator, a dehydration tower, and a purified natural gas separator connected in sequence by pipelines, wherein the purified natural gas separator is connected to an exhaust pipe, and further comprising a natural gas recovery device as described above, wherein the diversion pipe is connected to the exhaust pipe.

[0022] This utility model discloses a natural gas purification system. By connecting a recovery device to the exhaust pipe of the natural gas purification system, the residual natural gas in the system can be drawn out during the shutdown period, avoiding the problem of natural gas waste caused by direct discharge into the flare system.

[0023] In a third aspect, the present invention provides a fuel gas pipeline network, including a fuel gas separator tank connected to a gas transmission pipe, and also includes a natural gas recovery device as described above, wherein the diversion pipe is connected to the gas transmission pipe.

[0024] This utility model discloses a fuel gas pipeline network. By connecting a recovery device to the gas transmission pipe of the fuel gas pipeline network, the residual natural gas in the natural gas purification system is introduced into the fuel gas pipeline network during the shutdown of the purification system, and then transported to the natural gas user end, thus avoiding the waste of natural gas.

[0025] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. This utility model provides a natural gas recovery device. During the shutdown of the natural gas purification system, the residual natural gas at 5.8MPa in the natural gas purification system is depressurized through an angle valve and then transported to the fuel gas pipeline network. The device continues until the pressure of the natural gas purification system is reduced to 0.4MPa, which is equal to the pressure of the fuel gas pipeline network. Then, the shut-off component and the angle valve are closed, thereby realizing the recovery of residual natural gas in the natural gas purification system and avoiding the waste of natural gas. 2. This utility model provides a natural gas recovery device. During the normal operation of the natural gas purification system, the drain pipe is sealed by the shut-off component to prevent high-pressure gas from leaking into the fuel gas pipeline network and to ensure the normal operation of the natural gas purification system. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a natural gas recovery device according to the present invention; Figure 2 This is a diagram showing the usage status of a natural gas recovery device according to this utility model; Figure 3 This is a schematic diagram of the structure of a natural gas purification system according to this utility model; Figure 4 This is a schematic diagram of the structure of a fuel gas pipeline network according to this utility model; Marked in the image: 1-Drainage pipe, 101-First pipe section, 102-Second pipe section, 2-Shut-off assembly, 201-First valve, 202-Second valve, 3-Angle valve, 4-Pressure gauge, 5-Check valve, 6-Branch platform, 7-Tee, 8-Natural gas purification system, 801-Natural gas desulfurization tower, 802-Desulfurized gas separator, 803-Dehydration tower, 804-Purified natural gas separator, 805-Exhaust pipe, 9-Fuel gas pipeline network, 901-Fuel gas separator, 902-Gas transmission pipe. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to specific embodiments. However, it should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. All technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0028] Unless otherwise specified, the terms "upper," "lower," "left," "right," "center," "inner," and "outer" used in the description of specific embodiments of this utility model to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product / equipment / device is usually placed during use. These terms are merely for the purpose of facilitating the description of the utility model solution or simplifying the description in specific embodiments, and for enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on this utility model.

[0029] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are arranged as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when arranged in "horizontal," "vertical," "suspended," "parallel," or "coaxial" directions, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0030] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0031] Furthermore, in the description of the embodiments of this utility model, "several", "multiple", and "several" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0032] Furthermore, in the description of the technical solution of this utility model, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0033] Example 1 like Figure 1 and Figure 2 As shown, a natural gas recovery device includes a diversion pipe 1, which connects a natural gas purification system 8 and a fuel gas pipeline network 9. The diversion pipe 1 is equipped with a shut-off assembly 2 and an angle valve 3, wherein: The shut-off component 2 is used to cut off or seal the drainage tube 1; The angle valve 3 is used to regulate the pressure of the fuel gas delivered from the drain pipe 1 to the fuel gas pipeline 9.

[0034] In use, connect the two ends of the inlet pipe 1 to the natural gas purification system 8 and the fuel gas pipeline 9 respectively. During normal operation of the natural gas purification system 8, seal the inlet pipe 1 through the shut-off component 2 to prevent high-pressure gas from leaking into the fuel gas pipeline 9. During the shutdown of the natural gas purification system 8, open the shut-off component 2, and after depressurization through the angle valve 3, transport the 5.8MPa residual natural gas in the natural gas purification system 8 to the fuel gas pipeline 9 until the pressure of the natural gas purification system 8 is depressurized to 0.4MPa, which is equal to the pressure of the fuel gas pipeline 9. Then close the shut-off component 2 and the angle valve 3. The remaining natural gas in the natural gas purification system 8 is replaced by nitrogen and burned in the flare system for emission.

[0035] In one or more embodiments, the shut-off component 2 may include a first valve 201 and a second valve 202. Both the first valve 201 and the second valve 202 can cut off or seal the drainage pipe 1, providing double protection for the sealing of the drainage pipe 1 and reducing the probability of natural gas in the purification system leaking into the fuel gas pipeline 9 during the purification process.

[0036] First valve 201: First valve 201 is a gate valve.

[0037] Second valve 202: The second valve 202 is a stop valve. Both the gate valve used in the first valve 201 and the stop valve used in the second valve 202 can cut off or seal the drain pipe 1. However, they are different types of valves. Under the same working conditions, the probability of them failing together is smaller, thus improving the safety of the shut-off component 2 in sealing the drain pipe 1.

[0038] In one or more embodiments, the number of shut-off components 2 can be two, with the two shut-off components 2 respectively located on both sides of the angle valve 3. The independently set shut-off components 2 on both sides can form a double isolation barrier. Even if one side of the valve fails, the other side can still cut off the pipeline, greatly reducing the risk of natural gas leaking into the fuel gas pipeline network 9. Moreover, when the shut-off components 2 on both sides are closed at the same time, the angle valve 3 can be isolated, making it convenient to replace and maintain the angle valve 3 without having to empty the entire pipeline system, thus reducing downtime.

[0039] In one or more embodiments, a pressure gauge 4, a one-way valve 5, a branch pipe 6, and a tee 7 may also be installed on the drainage pipe 1.

[0040] Pressure gauge 4: There are two of them, one on each side of the angle valve 3, used to monitor the pressure inside the drainage pipe 1 and before and after the angle valve 3, and play the role of overpressure protection and leakage monitoring.

[0041] One-way valve 5: Located between angle valve 3 and fuel gas pipeline 9, it only allows natural gas to flow to the fuel gas pipeline, preventing natural gas in the fuel gas pipeline 9 from flowing back to the purification system in the later stage of exhaust.

[0042] Branch pipe assembly 6: Located at one end of the diversion pipe 1 that connects to the natural gas purification system 8, the branch pipe assembly 6 is a key component for connecting branch pipes to the main pipeline. It is mainly used for flow in the branch or merge pipeline system. It can be fixed to the main pipeline by welding, threaded connection or other methods. The diameter of the pipeline in the natural gas purification system 8 is larger, which is DN250, while the diameter of the diversion pipe 1 is smaller, which is DN80. By connecting the diversion pipe 1 to the pipeline in the natural gas purification system 8 through the branch pipe assembly 6, there is no need to cut or modify the main pipe as a whole, thereby reducing the complexity and cost of installation.

[0043] T-junction 7: Located at the end of the drain pipe 1 that connects to the fuel gas pipeline 9. The diameter of the pipe in the fuel gas pipeline 9 is small, DN100, which is not suitable for drilling holes to install the branch pipe platform 6. However, since the pipe is small, the t-junction 7 can be directly cut and installed, which is simpler and reduces the difficulty of connecting the drain pipe 1 and the fuel gas pipeline 9.

[0044] Example 2 like Figure 1 and Figure 2 As shown, the difference between this embodiment and the previous embodiment is that the drainage tube 1 includes a first pipe section 101 and a second pipe section 102 that are interconnected. The angle valve 3 is located at the end where the first pipe section 101 connects to the second pipe section 102. The first pipe section 101 is a stainless steel structural component with a wall thickness grade of SCH80, and the second pipe section 102 is a 20# carbon steel structural component with a wall thickness grade of SCH40.

[0045] In the drainage pipe 1: the section between the angle valve 3 and the natural gas purification system 8 is the first pipe section 101, which needs to withstand a gas pressure of 5.8MPa. Therefore, it is made of stainless steel to improve the pressure-bearing capacity of the first pipe section 101 and ensure the safety of the drainage pipe 1 during use; the section between the angle valve 3 and the fuel gas pipeline 9 is the second pipe section 102, which needs to withstand a gas pressure of 0.4MPa. Therefore, carbon steel structural components are selected, which can meet the strength requirements under low-pressure conditions and are more economical.

[0046] Example 3 like Figure 1 and Figure 3As shown, in this embodiment, a natural gas purification system is provided, including a natural gas desulfurization tower 801, a desulfurized gas separator 802, a dehydration tower 803, and a purified natural gas separator 804 connected in sequence by pipelines. The purified natural gas separator 804 is connected to an exhaust pipe 805. The system also includes a natural gas recovery device as described above, and the diversion pipe 1 is connected to the exhaust pipe 805.

[0047] This embodiment of a natural gas purification system connects a recovery device to the exhaust pipe 805 of the original natural gas purification system. During the shutdown period of the natural gas purification system, the residual natural gas in the natural gas purification system is drawn out, avoiding the problem of natural gas waste caused by direct discharge into the flare system.

[0048] Example 4 like Figure 1 and Figure 4 As shown, in this embodiment, a fuel gas pipeline network is provided, including a fuel gas separator 901, which is connected to a gas transmission pipe 902, and also includes a natural gas recovery device as described above, wherein the diversion pipe 1 is connected to the gas transmission pipe 902.

[0049] In this embodiment, a fuel gas pipeline network is provided. By connecting a recovery device to the gas transmission pipe 902 of the fuel gas pipeline network, the residual natural gas in the natural gas purification system is introduced into the fuel gas pipeline network during the shutdown of the purification system, and then transported to the natural gas user end, thus avoiding the waste of natural gas.

[0050] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A natural gas recovery device, characterized in that, Includes a drain pipe (1) for connecting the natural gas purification system (8) and the fuel gas pipeline network (9), and the drain pipe (1) is equipped with a shut-off assembly (2) and an angle valve (3), wherein: The shut-off component (2) is used to cut off or seal the drainage tube (1); The angle valve (3) is used to regulate the pressure of the fuel gas delivered from the drain pipe (1) to the fuel gas pipeline (9).

2. The natural gas recovery device according to claim 1, characterized in that, The shut-off component (2) includes a first valve (201) and a second valve (202), both of which can cut off or seal the drainage tube (1).

3. A natural gas recovery device according to claim 2, characterized in that, The first valve (201) is a gate valve, and the second valve (202) is a stop valve.

4. A natural gas recovery device according to claim 1, characterized in that, Two pressure gauges (4) are installed on the drainage tube (1), and the angle valve (3) is installed between the two pressure gauges (4).

5. A natural gas recovery device according to claim 1, characterized in that, A one-way valve (5) is provided on the drain pipe (1), and the one-way valve (5) is located between the angle valve (3) and the fuel gas pipeline (9).

6. A natural gas recovery device according to claim 1, characterized in that, The end of the diversion pipe (1) connected to the natural gas purification system (8) is provided with a branch pipe platform (6).

7. A natural gas recovery device according to claim 1, characterized in that, The end of the drain pipe (1) connected to the fuel gas pipeline (9) is provided with a tee (7).

8. A natural gas recovery device according to any one of claims 1-7, characterized in that, The drainage tube (1) includes a first pipe section (101) and a second pipe section (102) that are connected to each other. The angle valve (3) is located at the end of the first pipe section (101) that connects to the second pipe section (102). The first pipe section (101) is a stainless steel structural component, and the second pipe section (102) is a carbon steel structural component.

9. A natural gas purification system, comprising a natural gas desulfurization tower (801), a desulfurized gas separator (802), a dehydration tower (803), and a purified natural gas separator (804) connected sequentially by pipelines, wherein the purified natural gas separator (804) is connected to an exhaust pipe (805), characterized in that, It also includes a natural gas recovery device as described in any one of claims 1-8, wherein the inlet pipe (1) is connected to the exhaust pipe (805).

10. A fuel gas pipeline network, comprising a fuel gas separator (901), wherein the fuel gas separator (901) is connected to a gas transmission pipe (902), characterized in that, It also includes a natural gas recovery device as described in any one of claims 1-8, wherein the diversion pipe (1) is connected to the gas transmission pipe (902).

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