A LNG cylinder group gasification station BOG preferential gas supply device
By installing a check valve and a self-regulating inlet pressure regulating valve on the gas phase manifold of the LNG cylinder group vaporization station, the problem of pressure rise and overpressure caused by BOG was solved, ensuring the stability and continuity of gas supply, and reducing safety hazards and maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUANGZHOU EASTERN DEV GAS CO LTD
- Filing Date
- 2025-06-16
- Publication Date
- 2026-06-19
AI Technical Summary
Existing LNG cylinder regasification stations face the risk of pressure rise and overpressure during the gas supply process due to BOG (Boiler Gas). Furthermore, existing solutions increase construction costs and operation and maintenance expenses, and are not conducive to equipment miniaturization and skid-mounting.
Check valves are installed on the gas phase manifolds of the two sets of cryogenic steel cylinders at the LNG cylinder group vaporization station. A self-regulating pressure regulating valve and a BOG pressure regulator are installed on the gas phase main pipe before the BOG heater. The valve opening and closing are automatically controlled by the BOG pressure itself to prevent BOG backflow and ensure that BOG enters the pipeline network first.
It has achieved continuity and stability in the gas supply process of LNG cylinder group gasification station, reduced the probability of operational errors and accidents, reduced safety hazards and failure points, and simplified the complexity of maintenance and repair.
Smart Images
Figure CN224381267U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of gas supply device technology, and in particular to a BOG priority gas supply device for an LNG cylinder group gasification station. Background Technology
[0002] LNG cylinder depots are characterized by their flexibility, small footprint, simple supporting facilities, and low investment. In areas where municipal gas pipelines cannot reach in the near future, liquefied natural gas cylinder depots (LNG cylinder depots) are typically used as the gas source to supply residential and industrial users. To ensure continuous and stable gas supply during the LNG cylinder depot's gasification process, the LNG cryogenic cylinders are divided into two groups, operating in a one-in-use, one-in-standby mode.
[0003] During normal operation, LNG cylinders at an LNG vaporization station continuously evaporate LNG due to external heat input, producing boil-off gas (BOG). This is the main cause of increased pressure in LNG cylinders and even overpressure release. BOG priority supply means that when the pressure of any cylinder group exceeds the set value of the self-regulating valve's inlet pressure control valve, the BOG generated by that group of LNG cylinders enters the pipeline network before the LNG vaporized gas. This ensures that no cylinder group and its corresponding liquid / gas manifolds exceed the pressure limit, and does not affect the pressure of another cylinder group, thus ensuring a continuous and stable gas supply during the LNG vaporization station's operation.
[0004] The existing technology involves installing a self-regulating pressure regulating valve and pressure regulator on the gas phase main after the BOG heater. This solution ensures that the gas phase pipeline of the cylinder group is maintained below the set value of the self-regulating pressure regulating valve. However, as downstream users continuously consume natural gas, the LNG in the operating cylinder group decreases, and the pressure of natural gas in the gas phase pipeline gradually drops to the cylinder group switching pressure value, which is relatively low. After switching to the standby cylinder group, because the pressure in the cylinder group's gas phase space has dropped to a low level, there is not enough pressure differential for LNG to flow into the ambient air vaporizer, posing a risk of supply interruption.
[0005] Another option is to install a self-regulating pressure regulating valve on the vapor phase pipe of each cylinder group and a pressure regulator on the vapor phase main pipe after the BOG heater. In this option, the pressure in the vapor phase manifold of each cylinder group is independent; the pressure in the vapor phase pipe of the operating cylinder group will decrease, while the pressure in the vapor phase pipe of the standby cylinder group remains constant, allowing the liquid phase to smoothly enter the ambient air vaporizer after cylinder group switching. However, this option adds a set of self-regulating pressure regulating valves and a set of safety valves, increasing construction and operation / maintenance costs, and hindering equipment miniaturization and skid-mounting. Utility Model Content
[0006] The purpose of this utility model is to address the aforementioned shortcomings by providing a BOG priority gas supply device for LNG cylinder regasification stations.
[0007] To solve the above-mentioned technical problems, this utility model adopts the following technical solution: a BOG priority gas supply device for an LNG cylinder group vaporization station, which is respectively installed on the gas phase manifolds of two groups of LNG cryogenic steel cylinders, including:
[0008] Check valves are installed on the gas phase manifolds of the first and second bottle groups.
[0009] A self-operated pressure regulating valve is installed on the gas phase main pipe before the BOG heater.
[0010] The BOG regulator is installed on the vapor phase pipe after the BOG heater;
[0011] The check valve automatically opens and closes its disc based on the pressure flow of the BOG itself to prevent BOG backflow.
[0012] Furthermore, the number of check valves is two sets, namely a first check valve and a second check valve.
[0013] Furthermore, the first check valve and the second check valve are respectively installed at the ends of the first gas phase manifold and the second gas phase manifold of the first bottle group.
[0014] The beneficial effects of this utility model are reflected in:
[0015] This invention features a simple design that ensures that when the pressure of any LNG cylinder group exceeds the set value of the self-regulating valve, the BOG generated by that group can enter the pipeline network before the LNG vaporization gas. This guarantees that no LNG cylinder group and its corresponding liquid / gas manifold will be overpressurized, while also not affecting the pressure of other cylinder groups. This ensures the continuity and stability of the gas supply process of the LNG cylinder vaporization station. In addition, the system is intuitive and controllable to operate, effectively reducing the probability of operational errors and accidents, and minimizing potential safety hazards and points of failure. At the same time, its ease of maintenance significantly reduces the probability of malfunctions and the complexity of repairs. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the pipeline of this utility model;
[0017] Figure 2 This is a comparison diagram of the prior art of this utility model;
[0018] Figure 3 Comparative diagrams of two prior art technologies of this utility model;
[0019] Figure 4 This is a schematic diagram of the check valve pipeline flow according to this utility model.
[0020] In the picture:
[0021] 01. Gas phase manifold for the first bottle group; 02. Gas phase manifold for the second bottle group;
[0022] 1. Check valve; 11. First check valve; 12. Second check valve;
[0023] 2. Self-operated inlet pressure regulating valve;
[0024] 3. BOG voltage regulator;
[0025] 4. BOG heater. Detailed Implementation
[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present utility model, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.
[0027] Please see Figure 1-4 This utility model discloses an unattended LNG (liquefied natural gas) cylinder regasification station BOG (evaporated gas) priority gas supply device, which is respectively installed on the gas phase manifolds of two sets of LNG cryogenic steel cylinders, including:
[0028] Check valve 1 is installed on the gas phase manifold 01 of the first bottle group and the gas phase manifold 02 of the second bottle group.
[0029] Self-operated pressure regulating valve 2 is installed on the gas phase main pipe before BOG heater 4;
[0030] BOG regulator 3 is installed on the gas phase pipe after BOG heater 4;
[0031] The check valve 1 automatically opens and closes its disc based on the pressure flow of the BOG itself to prevent BOG backflow.
[0032] The gas supply device proposed in this application includes a first gas phase manifold 01 and a second gas phase manifold 02 connected to bottle group A and bottle group B respectively. A gas phase main pipe is provided at the intersection of the first gas phase manifold 01 and the second gas phase manifold 02. The gas phase main pipe is connected to the BOG heater 4. The output end of the BOG heater 4 is connected to the gas phase pipe. The BOG pressure regulator 3 is provided on the gas phase pipe.
[0033] It should be noted in this application that the number of check valves 1 is two sets, namely the first check valve 11 and the second check valve 12.
[0034] Furthermore, the first check valve 11 and the second check valve 12 are respectively installed at the ends of the first gas phase manifold 01 and the second gas phase manifold 02 of the first bottle group.
[0035] like Figure 4 As shown, through the above-mentioned check valve structure, during the normal operation of the LNG cylinder group vaporization station, due to the input of external heat energy, the LNG cylinders continuously generate BOG. At the same time, BOG gradually accumulates in the standby cylinder group B, causing the pressure to rise. Although the operating cylinder group A also generates BOG, due to the continuous consumption of natural gas by downstream users, the LNG liquid level gradually decreases, and the gas phase space increases accordingly, thus causing the pressure to drop. The pressure of the second cylinder group gas phase manifold 02 of cylinder group B is always greater than the pressure of the first cylinder group gas phase manifold 01 of cylinder group A. The valve disc of the second check valve 12 installed at the end of the gas phase manifold of cylinder group B is in the open state, and the BOG in cylinder group B flows into the gas phase main pipe before the BOG heater. Because the pressure of the gas phase main pipe before the BOG heater is greater than the pressure of the gas phase manifold of cylinder group A, the valve disc of the first check valve 11 installed at the end of the gas phase manifold of cylinder group A is in the closed state, and the BOG in the gas phase main pipe before the BOG heater cannot flow into the gas phase manifold of cylinder group A, ensuring that the pressures of cylinder groups A and B do not affect each other.
[0036] As the natural gas inside cylinder group B is continuously consumed, the internal pressure of the gas phase manifold 02 of the second cylinder group also decreases until the internal pressure of the corresponding cylinder group A rises under the input of external heat energy, until the pressure difference between the internal pressure of the gas phase manifold 01 of the first cylinder group and the gas phase manifold 02 of the second cylinder group can close the second check valve 12, and then the gas is transported by cylinder group A.
[0037] It should be noted that the first check valve 11 and the second check valve 12 will only conduct when there is a certain threshold pressure difference on both sides.
[0038] The pressure P1 generated by the BOG in the BOG heater's pre-vacuum main acts on the valve core of the self-operated pre-vacuum pressure regulating valve 2. Simultaneously, P1 is input through the control pipe to the upper diaphragm chamber of the actuator, acting on the top plate. The resulting force and the spring's reaction force determine the relative position of the valve core and valve seat, thus controlling the pre-vacuum pressure. When the pre-vacuum pressure P1 of the self-operated pre-vacuum pressure regulating valve 2 increases to the set value, the force of the top plate exceeds the spring's reaction force, causing the valve core to move away from the valve seat until the force of the top plate and the spring's reaction force are balanced. At this point, the flow area between the valve core and valve seat increases, the flow resistance decreases, and the BOG in the BOG heater's BOG becomes the post-vacuum pressure P2 after being throttled by the self-operated pre-vacuum pressure regulating valve 2.
[0039] The outlet pressure P3 of the BOG regulator 3 is set higher than the outlet pressure P4 of the LNG vaporization main line regulator. BOG gas at pressure P2 is heated by the BOG heater and then reduced to P3 by the BOG regulator 3. Since P3 is higher than P4, the LNG vaporization main line regulator will be closed. Therefore, the BOG gas preferentially passes through check valve 1, self-regulating inlet pressure regulating valve 2, and BOG regulator 3, ensuring priority entry into the pipeline network and preventing excessive pressure in the LNG cylinders and gas venting due to excessive pressure.
[0040] The design in this application is simple and enables the BOG generated by any LNG cylinder group to enter the pipeline network before the LNG vaporization gas when the pressure of any LNG cylinder group exceeds the set value of the self-regulating valve. This ensures that no LNG cylinder group and its corresponding liquid and gas manifold will be overpressurized, while not affecting the pressure of other cylinder groups. This guarantees the continuity and stability of the gas supply process of the LNG cylinder group vaporization station. In addition, the system is intuitive and controllable to operate, effectively reducing the probability of operational errors and accidents, and reducing potential safety hazards and failure points. At the same time, its ease of maintenance also significantly reduces the probability of failure and the complexity of maintenance.
[0041] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.
[0042] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.
[0043] Additionally, "multiple" refers to two or more.
[0044] 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, improvements, etc., 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 BOG priority gas supply device for an LNG cylinder group vaporization station, respectively installed on the gas phase manifolds of two sets of LNG cryogenic steel cylinders, characterized in that, include: Check valve (1) is installed on the gas phase manifold (01) of the first bottle group and the gas phase manifold (02) of the second bottle group; The self-operated pressure regulating valve (2) is installed on the gas phase main pipe in front of the BOG heater (4); BOG regulator (3) is installed on the gas phase pipe after BOG heater (4); The check valve (1) automatically opens and closes its disc by relying on the pressure flow of the BOG itself to prevent BOG backflow.
2. The BOG prioritization device for an LNG vessel group vaporization station of claim 1, wherein: The number of check valves (1) is two sets, namely the first check valve (11) and the second check valve (12).
3. The BOG priority gas supply device for an LNG cylinder group regasification station according to claim 2, characterized in that: The first check valve (11) and the second check valve (12) are respectively installed at the ends of the first gas phase manifold (01) and the second gas phase manifold (02).