Gas replacement purification method and gas replacement purification device for system pipeline

Abstract

The present invention discloses a gas replacement purification method and a gas replacement purification device for system pipelines, wherein the gas replacement purification method comprises: providing a system to be purified, introducing replacement gas into the system to be purified, and when the pressure in the system to be purified rises from the initial pressure P1 to the final pressure P2, stopping the introduction of replacement gas to exhaust and reduce the pressure of the system to be purified, so that the pressure in the system to be purified drops to the initial pressure P1, so as to complete a pulse replacement; repeating the above steps S101 to 103, so as to complete the pulse replacement for no less than n times. The present invention replaces the gas in the system by introducing replacement gas into the system to be purified, and replaces the gas in the system to be purified n times at the same time, thereby purifying the environment in the system. This method can realize efficient purification and replacement of complex system pipelines, further ensure the testing and operation safety of the FGSS system, especially the excellent replacement and purification effect of the "dead zone" inside the pipeline network.

Description

Technical Field

[0001] The invention relates to the technical field of ships and marine engineering, and in particular to a gas replacement purification method and a gas replacement purification device for system pipelines. Background Art

[0002] In recent years, the global liquefied gas shipping trade has grown significantly, and the number of liquefied gas ship orders has also risen accordingly. With the improvement of environmental protection requirements, dual-fuel powered ships are more popular with shipowners. The reliquefaction system and the fuel gas supply system (FGSS) are the two most representative liquid cargo systems of the current mainstream liquefied gas ships, and they are usually designed in a unitized manner. Before use, these system units need to use inert gas (usually nitrogen) to replace the air inside the system to reduce the oxygen content in the system. Generally, the target oxygen content of liquefied natural gas (LNG) is <5%, and the target oxygen content of liquefied petroleum gas (LPG) is <2%. Then the inert gas is replaced with the corresponding fuel gas (LNG / LPG) to ensure the safety of system startup.

[0003] However, reliquefaction systems and FGSS systems generally adopt a unitized design, with the characteristics of high integration, complex pipe networks, and many elbows and branches. If conventional purge method is used for replacement, not only the gas exchange efficiency is low, but also the "dead corners" of the complex pipe network cannot be thoroughly purified effectively, posing a safety hazard. Therefore, how to perform gas replacement to ensure that the complex pipe network can be replaced efficiently and safely has become an urgent problem to be solved. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a gas replacement and purification method and a gas replacement and purification device for system pipelines, so as to realize gas replacement and purification of complex piping systems and improve the replacement and purification efficiency.

[0005] In order to achieve the above-mentioned object and other related objects, the present invention provides a gas replacement purification method for a system pipeline, the gas replacement purification method comprising:

[0006] S101: providing a system to be purified;

[0007] S102: introducing replacement gas into the system to be purified, and when the pressure in the system to be purified rises from the initial pressure P1 to the final pressure P2, stopping introducing the replacement gas;

[0008] S103: exhaust and reduce the pressure of the system to be purified, so that the pressure in the system to be purified drops to the initial pressure P1, so as to complete a pulse replacement;

[0009] S104: Repeat the above steps S101 to S103 to complete the pulse replacement for no less than n times, wherein:

[0010]

[0011] n is the number of permutations, C SR is the target O2 concentration in the system to be purified, C SI is the O2 concentration in the system during gas replacement, C SG is the initial O2 concentration in the system to be purified, P1 is the initial pressure in the system to be purified, and P2 is the final pressure in the system to be purified.

[0012] Optionally, the system to be purified includes an air inlet and an air outlet; introducing the replacement gas into the system to be purified, further comprising:

[0013] The replacement gas is introduced from the air inlet of the system to be purified, and the air outlet of the system to be purified is closed.

[0014] Optionally, a first stop valve is provided on an air inlet pipe connected to an air inlet of the system to be purified, and a second stop valve is provided on an exhaust pipe connected to an air outlet of the system to be purified; before the replacement gas is introduced into the air inlet of the system to be purified and the air outlet of the system to be purified is closed, the method further includes:

[0015] Open the first stop valve and close the second stop valve.

[0016] Optionally, the exhaust gas pressure reduction of the system to be purified further includes:

[0017] Open the gas outlet of the system to be purified to discharge the replacement gas in the system to be purified;

[0018] When the pressure of the system to be purified drops to the initial pressure P1, the gas outlet of the system to be purified is closed.

[0019] Optionally, the exhaust gas pressure reduction of the system to be purified further includes:

[0020] Open the second stop valve on the exhaust pipe of the gas outlet of the system to be purified to discharge the replacement gas in the system to be purified;

[0021] When the pressure of the system to be purified drops to the initial pressure P1, the second stop valve on the gas outlet pipeline of the system to be purified is closed.

[0022] Optionally, the replacement gas is an inert gas.

[0023] Optionally, the system to be purified is a fuel gas supply system or a reliquefaction system.

[0024] The present invention also provides a gas replacement purification device for a system pipeline, comprising:

[0025] A replacement gas providing device, including a gas output end;

[0026] The system to be purified comprises an air inlet and an air outlet, wherein the air inlet of the system to be purified is connected to the gas output end through an air inlet channel;

[0027] The air permeable gardenia is connected with the air outlet of the system to be purified through an exhaust channel.

[0028] Optionally, the system to be purified is a reliquefaction system or a fuel gas supply system.

[0029] Optionally, the gas replacement purification device further comprises:

[0030] A first stop valve is arranged on an air inlet pipeline at an air inlet of the system to be purified;

[0031] The second stop valve is arranged on the exhaust pipe at the air outlet of the system to be purified.

[0032] Compared with the prior art, the gas replacement purification method and gas replacement purification device for system pipelines of the present invention have at least the following beneficial effects:

[0033] The gas replacement purification method of the present invention replaces the gas in the system by introducing replacement gas into the system to be purified, and replaces the gas in the system to be purified for no less than n times, thereby purifying the environment in the system. This method can achieve efficient purification and replacement of complex system pipe networks, further ensuring the testing and operation safety of the FGSS system, especially the replacement and purification effect of the "dead zone" inside the pipe network is excellent. In addition, the operation of this method does not require the installation of additional equipment, does not increase costs, has low operating difficulty, and has great feasibility.

[0034] According to calculations, compared with the traditional purging method, for general complex pipe networks, each replacement operation saves at least 50% of nitrogen consumption compared with the traditional purging method, which can significantly reduce costs and improve efficiency. At the same time, this method can be extended to the purification and replacement of other complex system pipelines, and can also be used for pipeline replacement and purification before the commissioning of gas, chemical and other pipelines for civil and industrial use.

[0035] The gas replacement purification device of the present invention uses a gas replacement purification method and also has the above-mentioned effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The figure is a schematic diagram of pipeline replacement of a part of the gas supply system (FGSS) of a liquefied petroleum gas (LPG) fuel-powered ship in an embodiment of the present invention, wherein the bold solid line with an arrow indicates the pipeline that needs nitrogen purification and replacement;

[0037] Figure 2 It is a schematic structural diagram of a pipeline replacement and purification device for a fuel gas supply system (FGSS) in an embodiment of the present invention.

[0038] List of reference numerals:

[0039] 1 System to be purified

[0040] 11 Air Inlet

[0041] 12 Air outlet

[0042] 2 First stop valve

[0043] 3 Second stop valve

[0044] 4 Replacement gas supply device

[0045] 41 Gas output

[0046] 5 Breathable Gardenia

[0047] 6 Metal hose DETAILED DESCRIPTION

[0048] The following specific embodiments illustrate the embodiments of the present invention, and those familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0049] It should be noted that the diagrams provided in the embodiments of the present invention are only used to illustrate the basic concept of the present invention in a schematic manner. Although the diagrams only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation, the form, quantity and proportion of each component can be changed at will during actual implementation, and the layout of the components may also be more complex. The structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions that can be implemented in this application, so they have no technical substantive significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in this application without affecting the effects and purposes that can be achieved by the present invention.

[0050] Example 1

[0051] This embodiment provides a gas replacement purification method for a system pipeline, comprising:

[0052] S101: providing a system to be purified;

[0053] Reference Figure 2, provide a system to be purified 1, which can be a gas supply system or a reliquefaction system. In this embodiment, refer to Figure 1 The system to be purified 1 is a gas supply system. This embodiment takes the gas supply system as an example and performs pulse gas replacement on it. The system to be purified 1 also includes an air inlet 11 and an air outlet 12. The air inlet 11 is used to pass gas into the system to be purified 1, and the air outlet 12 is used to discharge gas from the system to be purified 1.

[0054] Reference Figure 2 , a replacement gas providing device 4 is provided. The replacement gas in the replacement gas providing device 4 is an inert gas. In this embodiment, the replacement gas providing device 4 is a nitrogen bottle group or a nitrogen generator. The replacement gas is nitrogen, and the nitrogen is high-purity nitrogen with a concentration of ≥98%.

[0055] In this embodiment, refer to Figure 2 A first stop valve 2 is provided on the air inlet pipe connected to the air inlet 11 of the system to be purified 1, and the first stop valve 2 is used to control the introduction of replacement gas. A second stop valve 3 is provided on the exhaust pipe connected to the air outlet 12 of the system to be purified 1, and is used to control the discharge of gas in the system to be purified 1. When the replacement gas is introduced into the system to be purified 1, the first stop valve 2 needs to be opened. At the same time, the second stop valve 3 is closed to prevent the introduced replacement gas from flowing outward. Optionally, the replacement gas providing device 4 is connected to the system to be purified 1 through a metal hose 6, and the replacement gas is supplied from the replacement gas providing device 4 to the system to be purified 1 through the metal hose 6.

[0056] S102: introducing replacement gas into the system to be purified, and when the pressure in the system to be purified rises from the initial pressure P1 to the final pressure P2, stopping introducing the replacement gas;

[0057] Reference Figure 2 , connect the gas output end 41 of the replacement gas providing device 4 to the air inlet 11 of the system to be purified 1, so as to introduce the replacement gas into the air inlet 11 of the system to be purified 1, and at the same time, close the air outlet 12 of the system to be purified 1. Before the replacement gas is introduced, the initial pressure P1 of the system to be purified 1. In this embodiment, the first stop valve 2 on the air inlet pipeline at the air inlet 11 of the system to be purified 1 is opened, and the second stop valve 3 on the air outlet pipeline at the air outlet 12 of the system to be purified 1 is closed, so as to realize the introduction of replacement gas into the system to be purified 1.

[0058] Reference Figure 2In the process of introducing replacement gas into the air inlet 11 of the system to be purified 1, the pressure in the pipeline of the system to be purified 1 continues to rise. When the initial pressure P1 in the system to be purified 1 rises to the final pressure P2, at this time, the replacement gas supply of the replacement gas providing device 4 is closed, that is, the first stop valve 2 on the air inlet pipeline at the air inlet 11 of the system to be purified 1 is closed.

[0059] S103: exhaust and reduce the pressure of the system to be purified, so that the pressure in the system to be purified drops to the initial pressure P1, so as to complete a pulse replacement;

[0060] Reference Figure 2 , open the air outlet 12 of the system to be purified 1 to exhaust and reduce the pressure of the system to be purified 1. Keep the first stop valve 2 of the air inlet 11 of the system to be purified 1 closed, open the second stop valve 3 on the exhaust pipe of the air outlet 12 of the system to be purified 1, and let the high-pressure mixed gas in the pipe be discharged along the pipe. Optionally, a breathable valve 5 is also connected to the exhaust pipe of the air outlet 12 of the system to be purified 1. The high-pressure mixed gas in the system to be purified 1 is discharged by the breathable valve 5 through the air outlet 12 of the system to be purified 1. When the pressure in the system to be purified 1 drops to the initial pressure P1, close the second stop valve 3 of the air outlet 12 of the system to be purified 1, thereby completing a pulse replacement.

[0061] S104: Repeat the above steps S101 to S103 to complete pulse replacement for no less than n times, wherein:

[0062]

[0063] n is the number of permutations, C SR is the target O2 concentration in the system to be purified, C SI is the O2 concentration in the system during gas replacement, C SG is the initial O2 concentration in the system to be purified, P1 is the initial pressure in the system to be purified, and P2 is the final pressure in the system to be purified.

[0064] Among them, a portable oxygen concentration analyzer can be used to sample and detect the oxygen content in the system to be purified 1, and the sampling point should be selected according to the characteristics of the pipe network system of the system to be purified 1. Generally, the system designer will set exhaust valves or discharge valves at high and low points of the pipeline, and use these valves to take samples to check whether the pipe network purification is qualified. When the oxygen concentration at all sampling points, that is, C SR When <2%, the replacement operation is completed.

[0065] It should be noted that a pressure measuring device is also connected to the system to be purified 1 to test the initial pressure and the final pressure in the system to be purified 1 .

[0066] Example 2

[0067] This embodiment also provides a replacement purification device for system pipelines. Figure 2 The pipeline replacement purification device of the system includes a replacement gas providing device 4, a system to be purified 1, and a ventilating device 5. The pipeline replacement gas providing device 4 includes a gas output terminal 41; the system to be purified 1 includes an air inlet 11 and an air outlet 12, the air inlet 11 of the system to be purified 1 is connected to the gas output terminal 41, and the air outlet 12 of the system to be purified 1 is connected to the ventilating device 5.

[0068] The replacement gas providing device 4 is used to provide replacement gas to the system to be purified 1. The replacement gas in the replacement gas providing device 4 is an inert gas. In this embodiment, the replacement gas providing device 4 is a nitrogen bottle group or a nitrogen generator, and the replacement gas is nitrogen, which is high-purity nitrogen with a concentration of ≥98%.

[0069] The system to be purified 1 may be a gas supply system or a reliquefaction system. Figure 1 The system to be purified 1 is a gas supply system. This embodiment takes the gas supply system as an example and performs pulse gas replacement on it. The system to be purified 1 also includes an air inlet 11 and an air outlet 12. The air inlet 11 is used to pass gas into the system to be purified 1, and the air outlet 12 is used to discharge gas from the system to be purified 1.

[0070] In this embodiment, a first stop valve 2 is provided on the air inlet pipe connected to the air inlet 11 of the system to be purified 1, and the first stop valve 2 is used to control the introduction of replacement gas. A second stop valve 3 is provided on the exhaust pipe connected to the air outlet 12 of the system to be purified 1, and is used to control the discharge of gas in the system to be purified 1. When the replacement gas is introduced into the system to be purified 1, the first stop valve 2 needs to be opened. At the same time, the second stop valve 3 is closed to prevent the introduced replacement gas from flowing outward. Optionally, the replacement gas providing device 4 is connected to the system to be purified 1 through a metal hose 6, and the replacement gas is supplied from the replacement gas providing device 4 to the system to be purified 1 through the metal hose 6.

[0071] The exhaust pipe at the air outlet 12 of the system to be purified 1 is also connected to a ventilation device 5, which is used for ventilation of the system to be purified 1.

[0072] In summary, the gas replacement purification method of the present invention replaces the gas in the system by introducing replacement gas into the system to be purified, and replaces the gas in the system to be purified n times, thereby purifying the environment in the system. This method can achieve efficient purification and replacement of complex system pipe networks, further ensuring the testing and operation safety of the FGSS system, especially the replacement and purification effect of the "dead zone" inside the pipe network is excellent. In addition, the operation of this method does not require the installation of additional equipment, does not increase costs, has low operating difficulty, and has great feasibility.

[0073] According to calculations, compared with the traditional purging method, for general complex pipe networks, each replacement operation saves at least 50% of nitrogen consumption compared with the traditional purging method, which can significantly reduce costs and improve efficiency. At the same time, this method can be extended to the purification and replacement of other complex system pipelines, and can also be used for pipeline replacement and purification before the commissioning of gas, chemical and other pipelines for civil and industrial use.

[0074] The gas replacement purification device of the present invention uses a system replacement purification method and also has the above-mentioned effects.

[0075] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A gas replacement purification method for system pipelines, characterized in that: include: S101: providing a system to be purified; S102: introducing replacement gas into the system to be purified, and when the pressure in the system to be purified rises from an initial pressure P1 to a final pressure P2, stopping introducing the replacement gas; S103: exhausting and reducing the pressure of the system to be purified, so that the pressure in the system to be purified drops to the initial pressure P1, so as to complete a pulse replacement; S104: Repeat steps S101 to S103 to complete pulse replacement for no less than n times, wherein: n is the number of permutations, C SR is the target O2 concentration in the system to be purified, C SI is the O2 concentration in the system during gas replacement, C SG is the initial O2 concentration in the system to be purified, P1 is the initial pressure in the system to be purified, P2 is the final pressure in the system to be purified.

2. The gas replacement purification method according to claim 1, characterized in that: The system to be purified comprises an air inlet and an air outlet; introducing the replacement gas into the system to be purified, and further comprising: The replacement gas is introduced from the air inlet of the system to be purified, and the air outlet of the system to be purified is closed.

3. The gas replacement purification method according to claim 2, characterized in that: A first stop valve is provided on the air inlet pipe connected to the air inlet of the system to be purified, and a second stop valve is provided on the exhaust pipe connected to the air outlet of the system to be purified; before the replacement gas is introduced into the air inlet of the system to be purified and the air outlet of the system to be purified is closed, the method further includes: Open the first stop valve and close the second stop valve.

4. The gas replacement purification method according to claim 2, characterized in that: Exhausting and reducing the pressure of the system to be purified also includes: Opening the gas outlet of the system to be purified to discharge the replacement gas in the system to be purified; When the pressure of the system to be purified drops to the initial pressure P1, the gas outlet of the system to be purified is closed.

5. The gas replacement purification method according to claim 3, characterized in that: The exhaust pressure reduction of the system to be purified also includes: Opening the second stop valve on the exhaust pipe of the gas outlet of the system to be purified to discharge the replacement gas in the system to be purified; When the pressure of the system to be purified drops to the initial pressure P1, the second stop valve on the gas outlet pipeline of the system to be purified is closed.

6. The gas replacement purification method according to claim 1, characterized in that: The replacement gas is an inert gas.

7. The gas replacement purification method according to claim 1, characterized in that: The system to be purified is a gas supply system or a reliquefaction system.

8. A gas replacement purification device for a system pipeline, characterized in that: The gas replacement purification device is applied to the gas replacement purification method according to any one of claims 1 to 7, and the gas replacement purification device comprises: A replacement gas providing device, including a gas output end; The system to be purified comprises an air inlet and an air outlet, wherein the air inlet of the system to be purified is connected to the gas output end through an air inlet channel; The air-permeable gardenia is connected with the air outlet of the system to be purified through an exhaust passage.

9. The gas replacement purification device according to claim 8, characterized in that: The system to be purified is a reliquefaction system or a gas supply system.

10. The gas replacement purification device according to claim 8, characterized in that: The gas replacement purification device also includes: A first stop valve is arranged on an air inlet pipeline at an air inlet of the system to be purified; The second stop valve is arranged on the exhaust pipe at the air outlet of the system to be purified.

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