Recycling device for natural gas conveying leakage gas

Abstract

The utility model discloses a natural gas conveying leakage gas recycling device which comprises a recycling chamber, a gas inlet pipe, a gas outlet pipe and a gas outlet pipe. The pressure control module is used for controlling the gas pressure in the recovery chamber; a compressor for increasing gas pressure; the buffer tank is used for stabilizing the pressure of gas flowing into the compressor; the compressor is provided with an output pipe used for outputting gas, and the output pipe is connected with a natural gas conveying pipeline. Leaked gas is recycled by arranging a recycling device, control over gas pressure is increased by arranging a pressure control module, and the situation that pressure in a recycling chamber is too large, and end face sealing in a natural gas conveying pipeline is affected is avoided; when the pressure in the recovery chamber is high, part of gas is discharged to reduce the pressure; the buffer tank is arranged and used for stabilizing the pressure of gas conveyed to the compressor, the pressure of a gas inlet of the compressor is kept stable, and the situation that the pressure fluctuation amplitude is too large or too frequent is avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of gas recovery, and in particular relates to a device for recovering and utilizing leaked gas during natural gas transportation. Background Art

[0002] The natural gas pipelines that have been built so far include the West-East Gas Pipeline Line 1, Line 2, and Line 3, the Yulin-Jinan Pipeline, the Shaanxi-Beijing Pipeline, the Sichuan-Eastern Gas Pipeline, and other main pipelines. Compressor stations are set up in the natural gas pipeline transportation, and compressor units are installed to pressurize the natural gas. The axial end seals of the compressor units generally use series dry gas seals without intermediate labyrinths. The first-level seal leaks more natural gas, and the first-level seal is the seal on the medium side, while the second-level seal leaks less gas.

[0003] At present, there are two methods to deal with the leakage of shaft-end seals in natural gas transportation. First, directly vent it through the vent pipe, which will not only waste energy but also cause environmental pollution. Second, the leaked gas is recycled, mainly the leakage of the primary seal. The dry gas seal vent pipes of all compressors at the drive end and non-drive end of the compressor station are connected together after passing through a one-way valve, and then filtered into the reciprocating compressor for pressurization. According to the equipment conditions on site of the compressor station, the recovered natural gas can be used for domestic gas or generator gas, etc. However, this recovery system has relatively high environmental requirements and a simple structure, and is less suitable for compressor stations operating in the field.

[0004] The above information disclosed in the background technology is only used to increase the understanding of the background technology of the present application, and therefore, it may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] In view of the above problems in the prior art, the utility model proposes a device for recycling leaked gas during natural gas transportation, which can recover the leaked gas and has strong matching and applicability; and the recovered gas is re-transported to the natural gas transmission pipeline, thereby reducing the loss during the natural gas transportation process.

[0006] In order to achieve the above-mentioned utility model purpose, the utility model adopts the following technical solutions:

[0007] A device for recycling leaked gas during natural gas transmission, comprising:

[0008] a recovery chamber, which is used to collect leaking natural gas;

[0009] A pressure control module, which is used to control the gas pressure in the recovery chamber;

[0010] A compressor, which is used to increase the pressure of the gas;

[0011] A buffer tank for stabilizing the pressure of the gas flowing into the compressor;

[0012] The compressor is provided with an output pipe for outputting gas, and the output pipe is connected to the natural gas transmission pipeline.

[0013] In some embodiments of the present application, a gas processing module is further included, which is arranged between the recovery chamber and the buffer tank, and is used to filter and remove liquid from the recovered gas; the gas processing module has two filters arranged in parallel.

[0014] In some embodiments of the present application, a flow meter for measuring the amount of recovered gas is further included, and the flow meter is arranged between the gas processing unit and the buffer tank.

[0015] In some embodiments of the present application, a return pipe for stabilizing the compressor inlet pressure is further included, and the return pipe transports the gas output by the compressor to the buffer tank.

[0016] In some embodiments of the present application, a control valve for controlling the opening or closing of the reflux pipe is provided on the reflux pipe.

[0017] In some embodiments of the present application, a main control module and a pressure sensor for measuring the pressure in the buffer tank are further included, and the frequency of the compressor is adjustable.

[0018] In some embodiments of the present application, the pressure control module has a back pressure valve and a pneumatic switch valve respectively connected to the recovery chamber, and the starting pressure of the back pressure valve is lower than the starting pressure of the pneumatic switch valve.

[0019] In some embodiments of the present application, the pressure control module also has a manual switch valve connected to the recovery chamber, a first pressure relief pipe connected between the recovery chamber and the back pressure valve, a second pressure relief pipe connected between the recovery chamber and the pneumatic switch valve, and a bypass pipe connected between the first pressure relief pipe and the second pressure relief pipe, and the manual switch valve is arranged on the bypass pipe.

[0020] In some embodiments of the present application, the recovery chamber is connected to a primary sealed exhaust pipe of a compressor on a natural gas transmission pipeline, and a one-way valve is provided on the exhaust pipe.

[0021] In some embodiments of the present application, an impeller is provided at the inlet of the recovery chamber.

[0022] Compared with the prior art, the advantages and positive effects of the utility model are: by setting up a recycling device to recycle the leaked gas, by setting up a pressure control module, the control of the gas pressure is increased to avoid excessive pressure in the recovery chamber, which affects the end face seal in the natural gas transmission pipeline; when the pressure in the recovery chamber is high, part of the gas is discharged to reduce the pressure; by setting up a buffer tank, the gas pressure delivered to the compressor is stabilized to keep the gas inlet pressure of the compressor stable to avoid excessive or too frequent pressure fluctuations. By setting up the recycled gas to be re-delivered to the natural gas transmission pipeline, the pipeline for recycling the leaked gas is reduced, and the loss during the natural gas transmission process is reduced.

[0023] After reading the specific embodiments of the present invention in conjunction with the accompanying drawings, other features and advantages of the present invention will become more clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, a brief introduction will be given below to the drawings required for use in the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 This is a schematic structural diagram of an embodiment of a device for recycling leaked gas during natural gas transmission proposed by the utility model;

[0026] Figure 2 for Figure 1 A schematic diagram of the structure from another angle;

[0027] Figure 3 for Figure 1 A schematic diagram of the structure of the recovery chamber and the pressure control module;

[0028] Among them, the recycling device 100;

[0029] Buffer tank 1; flow meter 2; recovery chamber 3; main chamber 31; impeller 32; back pressure valve 4; pneumatic switch valve 5; manual switch valve 6; filter 7; 8. Motor; output pipe 9; compressor 10; main control module 11; return pipe 12; first pressure discharge pipe 13; second pressure discharge pipe 14. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present utility model clearer, the technical solution in the embodiments of the present utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the present utility model.

[0031] In the description of the present utility model, it should be noted that the terms "upper", "lower", "left", "right", etc. indicate directions or positional relationships based on the positional relationships shown in the accompanying drawings, with the gas delivery direction being "front" and the opposite being "back". The terms are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0032] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0034] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples, and the purpose is not to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and / or the use of other materials.

[0035] See also Figure 1-Figure 3 , is an embodiment of a natural gas transmission leaked gas recovery and utilization device proposed by the utility model, a natural gas transmission leaked gas recovery and utilization device 100 comprises: a buffer tank 1, a recovery chamber 3, a compressor 10 and a pressure control module, the recovery chamber 3 is used to collect leaked natural gas, and the pressure control module is used to control the gas pressure in the recovery chamber 3. The compressor 10 is used to increase the gas pressure, and the buffer tank 1 is used to stabilize the gas pressure flowing into the compressor 10. The compressor 10 is provided with an output pipe 9 for outputting gas, and the output pipe 9 is connected to the natural gas transmission pipeline.

[0036] In this embodiment, a recycling device 100 is provided to recycle the leaked gas. By providing a pressure control module, the control of the gas pressure is increased to avoid excessive pressure in the recovery chamber 3, which may affect the end face seal in the natural gas transmission pipeline. When the pressure in the recovery chamber 3 is high, part of the gas is discharged to reduce the pressure. By providing a buffer tank 1, the gas pressure delivered to the compressor 10 is stabilized to keep the gas inlet pressure of the compressor 10 stable and avoid excessive or frequent pressure fluctuations. By providing the recovered gas to be re-delivered to the natural gas transmission pipeline, the pipeline for recycling the leaked gas is reduced, and the loss during the natural gas transmission process is reduced.

[0037] In some embodiments of the present application, the recycling device 100 also includes a gas processing module arranged between the recovery chamber 3 and the buffer tank 1, which is used to filter and remove liquid from the recovered gas to prevent particles or liquids in the natural gas from affecting the operation of the subsequent compressor. The gas processing module has two filters 7 arranged in parallel, and cut-off valves are arranged upstream and downstream of the filter 7 to cut off the gas flow path and replace the filter element of the filter 7. A condensate discharge valve is arranged at the bottom of the filter 7. By setting two filters 7 arranged in parallel, the filter element can be replaced without stopping the machine. Only one filter 7 is used in normal operation, and the other is in standby state. When the working filter 7 is blocked, the upstream and downstream cut-off valves of the standby filter 7 can be opened, and the upstream and downstream cut-off valves of the blocked filter 7 can be closed. After the pressure is released through the bottom condensate discharge valve, the filter element of the filter 7 can be replaced.

[0038] In some embodiments of the present application, the recycling device 100 also includes a flow meter 2 for measuring the amount of recovered gas, and the flow meter 2 is arranged between the gas processing unit and the buffer tank 1. The recovered natural gas is measured after filtration and is used to accumulate the recovered natural gas. It is also possible to monitor and record the temperature, pressure, and instantaneous flow of the recovered natural gas in real time, and accurately calculate the volume accumulation under standard conditions and operating conditions. The monitoring of instantaneous flow is of great significance because it can help us judge the operating status of the end face seal of the natural gas unit. By monitoring the instantaneous flow, possible problems in the dry gas sealing system can be discovered and solved in a timely manner, ensuring the normal operation of the system and reducing the leakage and waste of natural gas. The flow meter 2 not only provides accurate measurement and accounting of the recovered natural gas, but also provides key operating status information by monitoring the instantaneous flow, thereby improving the operating efficiency and energy conservation and environmental protection level of the system.

[0039] In some embodiments of the present application, the recycling device 100 further includes a return pipe 12 for stabilizing the compressor inlet pressure, and the return pipe 12 delivers the gas output by the compressor to the buffer tank 1. This is to supplement the insufficient supply of recycled natural gas, stabilize the inlet pressure of the compressor 10, and ensure the normal operation and gas supply pressure of the compressor 10. A control valve for controlling the opening or closing of the return pipe 12 is provided on the return pipe 12, and the opening or closing of the control valve can be driven according to the pressure in the buffer tank 1.

[0040] In some embodiments of the present application, the recycling device 100 further includes a main control module 11 and a pressure sensor for measuring the pressure in the buffer tank 1, and the frequency of the compressor 10 is adjustable. The reciprocating frequency of the compressor 10 can be changed by a frequency converter to control the recycling amount of the recycling device 100. When the pressure in the buffer tank 1 is high, the reciprocating frequency of the compressor 10 is increased, and vice versa, the reciprocating frequency of the compressor 10 is reduced.

[0041] In some embodiments of the present application, the pressure control module has a back pressure valve 4 and a pneumatic switch valve 5 respectively connected to the recovery chamber 1, and the starting pressure of the back pressure valve 4 is less than the starting pressure of the pneumatic switch valve 5. If the leakage of the first level of the shaft end seal exceeds the maximum processing capacity of the recycling device 100, it will cause the pressure in the recovery chamber 3 to rise. When the pressure reaches the starting pressure of the back pressure valve 4, the back pressure valve will automatically open to discharge gas for pressure reduction. When the pressure in the recovery chamber 3 reaches the starting pressure of the pneumatic switch valve 5, the main control module 11 controls the pneumatic switch valve 5 to open.

[0042] In some embodiments of the present application, the pressure control module further comprises a manual switch valve 6 connected to the recovery chamber 3, a first pressure discharge pipe 13 connected between the recovery chamber 3 and the back pressure valve 4, a second pressure discharge pipe 14 connected between the recovery chamber 3 and the pneumatic switch valve 5, and a bypass pipe connected between the first pressure discharge pipe 13 and the second pressure discharge pipe 14, and the manual switch valve 6 is arranged on the bypass pipe. The manual switch valve 6 is used as a bypass of the back pressure valve 4 and the pneumatic switch valve 5 when the machine is turned on; when the recycling device 100 is out of use for a long time, the manual switch valve 6 can also be opened as a discharge pipe.

[0043] In some embodiments of the present application, the recovery chamber 3 is connected to the primary sealed exhaust pipe of the compressor on the natural gas transmission pipeline, and a one-way valve is provided on the exhaust pipe; the recovery chamber 3 has a main chamber 31, and an impeller 32 is provided at the entrance of the main chamber 31, and the impeller 32 is used to drive the gas to flow into the main chamber 31.

[0044] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the above embodiments, or to replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present invention.

Claims

1. A device for recycling leaked natural gas during transportation, characterized in that: include: a recovery chamber, which is used to collect leaking natural gas; A pressure control module, which is used to control the gas pressure in the recovery chamber; A compressor, which is used to increase the pressure of the gas; A buffer tank for stabilizing the pressure of the gas flowing into the compressor; The compressor is provided with an output pipe for outputting gas, and the output pipe is connected to the natural gas transmission pipeline.

2. The recycling device according to claim 1, characterized in that: It also includes a gas processing module arranged between the recovery chamber and the buffer tank, which is used to filter and remove liquid from the recovered gas; the gas processing module has two filters arranged in parallel.

3. The recycling device according to claim 2, characterized in that: It also includes a flow meter for measuring the amount of recovered gas, and the flow meter is arranged between the gas processing module and the buffer tank.

4. The recycling device according to claim 1, characterized in that: The utility model also comprises a return pipe for stabilizing the inlet pressure of the compressor, wherein the return pipe conveys the gas output by the compressor to the buffer tank.

5. The recycling device according to claim 4, characterized in that: The return pipe is provided with a control valve for controlling the opening or closing of the return pipe.

6. The recycling device according to any one of claims 1 to 5, characterized in that: It also includes a main control module and a pressure sensor for measuring the pressure in the buffer tank, and the frequency of the compressor is adjustable.

7. The recycling device according to any one of claims 1 to 5, characterized in that: The pressure control module comprises a back pressure valve and a pneumatic switch valve respectively connected to the recovery chamber, and the starting pressure of the back pressure valve is lower than the starting pressure of the pneumatic switch valve.

8. The recycling device according to claim 7, characterized in that: The pressure control module also has a manual switch valve connected to the recovery chamber, a first pressure relief pipe connected between the recovery chamber and the back pressure valve, a second pressure relief pipe connected between the recovery chamber and the pneumatic switch valve, and a bypass pipe connected between the first pressure relief pipe and the second pressure relief pipe, and the manual switch valve is arranged on the bypass pipe.

9. The recycling device according to any one of claims 1 to 5, characterized in that: The recovery chamber is connected to a primary sealed exhaust pipe of a compressor on a natural gas transmission pipeline, and a one-way valve is arranged on the exhaust pipe.

10. The recycling device according to any one of claims 1 to 5, characterized in that: An impeller is arranged at the inlet of the recovery chamber.

Images