LNG (Liquefied Natural Gas) pressurizing and vaporizing gas supply system

Abstract

The utility model discloses an LNG (liquefied natural gas) pressurization vaporization gas supply system which comprises a main liquid supply pipe, and a first low-temperature stop valve, a filter, an LNG plunger pump, a check valve, a damper, a pressure transmitter, a second low-temperature stop valve, a first electric stop valve, a first air temperature type vaporizer, a pressure gauge and a temperature transmitter are sequentially mounted on the main liquid supply pipe in the LNG conveying direction. The portion, between the second low-temperature stop valve and the first electric stop valve, of the main liquid supply pipe and the portion, between the first air temperature type vaporizer and the pressure gauge, of the main liquid supply pipe are connected with an emptying main pipe through connecting pipes correspondingly, and a first safety valve and a second safety valve are installed on the two connecting pipes correspondingly. By arranging the LNG plunger pump, the PLC control cabinet and the two air temperature type vaporizers, utilization after LNG pressurization and vaporization is achieved, the problem of large-flow LNG pressurization is solved, full-automatic control is basically achieved in the whole operation process, safety accidents such as man-made misoperation, overpressure and leakage are reduced to the maximum extent, operation is easy and convenient, and safety is high.

Description

Technical Field

[0001] The utility model relates to the technical field of LNG gas supply equipment, and specifically relates to an LNG pressurizing and vaporizing gas supply system. Background Technique

[0002] At present, LNG (liquefied natural gas) pressurization mostly adopts the method of submersible pump pressurization. However, submersible pumps with large flow rates and high lift are expensive, and because the submersible pump must be installed in the pump pool and must be immersed in low-temperature LNG, this installation method is very likely to cause natural vaporization of LNG, and the leakage risk is relatively high; in L-CNG (the process of converting LNG into compressed natural gas (CNG) through vaporization and pressurization) gas filling stations, generally after LNG is vaporized, the method of pressurization by a compressor is adopted, and this method requires additional supporting equipment such as a buffer tank at the inlet end of the compressor, and the investment is relatively high; so there are deficiencies. Content of the Utility Model

[0003] In view of the deficiencies existing in the prior art, the utility model provides an LNG pressurizing and vaporizing gas supply system, which is used to solve the problems of relatively high cost and safety risks existing in LNG pressurizing and vaporizing in the prior art.

[0004] To solve the above technical problems, the utility model provides the following technical solutions:

[0005] An LNG pressurizing and vaporizing gas supply system includes a main liquid supply pipe, and a cryogenic stop valve I, a filter, an LNG piston pump, a check valve, a damper, a pressure transmitter, a cryogenic stop valve II, an electric cut-off valve I, an air-cooled vaporizer I, a pressure gauge and a temperature transmitter are sequentially installed on the main liquid supply pipe along the LNG transportation direction;

[0006] On the main liquid supply pipe between the cryogenic stop valve II and the electric cut-off valve I and on the main liquid supply pipe between the air-cooled vaporizer I and the pressure gauge are respectively connected to the vent main pipe through connecting pipes, and a safety valve I and a safety valve II are respectively installed on the two connecting pipes;

[0007] It further includes a PLC control cabinet, and the LNG piston pump, the electric cut-off valve I, the pressure transmitter and the temperature transmitter are all electrically connected to the PLC control cabinet.

[0008] Preferably, a liquid supply pipe is connected in parallel to the main liquid supply pipe at the positions corresponding to the electric cut-off valve I and the air-cooled vaporizer I, and an electric cut-off valve II and an air-cooled vaporizer II are sequentially installed on the liquid supply pipe along the LNG transportation direction.

[0009] Preferably, the electric cut-off valve II is electrically connected to the PLC control cabinet.

[0010] Preferably, both the air-cooled vaporizer I and the air-cooled vaporizer II are aluminum fin vaporizers formed by integral welding.

[0011] Preferably, it further includes a combustible gas detector, and the combustible gas detector is electrically connected to the PLC control cabinet.

[0012] Preferably, it further includes an explosion-proof audible and visual alarm, and the explosion-proof audible and visual alarm is electrically connected to the PLC control cabinet.

[0013] Compared with the prior art, the present utility model has the following beneficial effects:

[0014] The present utility model realizes the utilization of LNG after pressurization and vaporization by setting an LNG piston pump, a PLC control cabinet and two air-cooled vaporizers. It not only solves the problem of large-flow LNG pressurization, but also the whole operation process is basically fully automatic controlled, including the start and stop of the LNG piston pump, pressure control, leakage monitoring, and the switching of the two air-cooled vaporizers, minimizing the occurrence of safety accidents such as human error, overpressure, and leakage. It can be widely applied to L-CNG filling stations, natural gas to hydrogen, natural gas to methanol, etc. It has broad market promotion and application prospects, is easy to operate and has high safety, and solves the problems of high cost and high safety risk existing in LNG pressurization and vaporization in the prior art. Description of the Drawings

[0015] Figure 1 is the overall structural schematic diagram of the present utility model;

[0016] Figure 2 is the system schematic diagram of the present utility model.

[0017] In the figure: 1, total liquid supply pipe; 2, low-temperature stop valve I; 3, filter; 4, LNG piston pump; 5, check valve; 6, damper; 7, pressure transmitter; 8, low-temperature stop valve II; 9, electric cut-off valve I; 10, air-cooled vaporizer I; 11, pressure gauge; 12, temperature transmitter; 13, connecting pipe; 14, vent main pipe; 15, safety valve I; 16, safety valve II; 17, PLC control cabinet; 18, liquid supply pipe; 19, electric cut-off valve II; 20, air-cooled vaporizer II; 21, combustible gas detector; 22, explosion-proof audible and visual alarm. Detailed Embodiments

[0018] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present utility model.

[0019] As Figure 1-2 shown, the present utility model provides a technical solution: an LNG pressurizing and vaporizing gas supply system, including a main liquid supply pipe 1, on which a cryogenic stop valve 1, a filter 3, an LNG plunger pump 4, a check valve 5, a damper 6, a pressure transmitter 7, a cryogenic stop valve 2, an electric cut-off valve 1, an air-cooled vaporizer 1, a pressure gauge 11 and a temperature transmitter 12 are successively installed along the LNG transportation direction;

[0020] On the main liquid supply pipe 1 between the cryogenic stop valve 2 and the electric cut-off valve 1 and on the main liquid supply pipe 1 between the air-cooled vaporizer 1 and the pressure gauge 11 are respectively connected to the vent main pipe 14 through connecting pipes 13, and a safety valve 1 and a safety valve 2 are respectively installed on the two connecting pipes 13;

[0021] A liquid supply pipe 18 is connected in parallel at the positions of the main liquid supply pipe 1 corresponding to the electric cut-off valve 1 and the air-cooled vaporizer 1. An electric cut-off valve 2 and an air-cooled vaporizer 2 are successively installed on the liquid supply pipe 18 along the LNG transportation direction. Both the air-cooled vaporizer 1 and the air-cooled vaporizer 2 are aluminum fin vaporizers integrally welded and formed;

[0022] It also includes a PLC control cabinet 17. The LNG plunger pump 4, the electric cut-off valve 1, the pressure transmitter 7 and the temperature transmitter 12 are all electrically connected to the PLC control cabinet 17. The electric cut-off valve 2 is electrically connected to the PLC control cabinet 17. It also includes a combustible gas detector 21, which is electrically connected to the PLC control cabinet 17. It also includes an explosion-proof sound and light alarm 22, which is electrically connected to the PLC control cabinet 17.

[0023] Working principle:

[0024] By setting the damper 6, the vibration impact of the LNG piston pump 4 on the total liquid supply pipe 1 is reduced; the LNG piston pump 4 is electrically connected to the PLC control cabinet 17, and the PLC control cabinet 17 self-detects, controls and adjusts the operating state of the LNG piston pump 4 itself. When the outlet pressure of the LNG piston pump 4 reaches the upper pressure limit, it stops running, and when the pressure drops to the lower pressure limit, it starts running; by setting two air-cooled vaporizers, namely the air-cooled vaporizer 10 and the air-cooled vaporizer 20, and the inlet ends are respectively provided with an electric cut-off valve 9 and an electric cut-off valve 19, and the outlet end of the air-cooled vaporizer is provided with a temperature transmitter 12 electrically connected to the PLC control cabinet 17. When the outlet temperature of the air-cooled vaporizer is lower than the lower limit, the PLC control cabinet 17 drives the opening and closing of the electric cut-off valve 9 and the electric cut-off valve 19 to realize the switching and operation between the air-cooled vaporizer 10 and the air-cooled vaporizer 20, ensuring that the outlet temperature requirement is met when the air-cooled vaporizer is continuously used, and preventing serious consequences caused by low-temperature gas or even liquid flowing into the downstream carbon steel pipeline system such as the total liquid supply pipe 1; the LNG flows through the cryogenic stop valve and the filter 3 and then enters the LNG piston pump 4. The LNG piston pump 4 pressurizes the LNG and transports it to the air-cooled vaporizer 10 or the air-cooled vaporizer 20. The natural gas passing through the air-cooled vaporizer 10 or the air-cooled vaporizer 20 is close to normal temperature and is supplied to the downstream gas-using points; the PLC control cabinet 17 is connected with a combustible gas detector 21 and an explosion-proof sound and light alarm 22, which can give timely reminders when an accident occurs.

[0025] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0026] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An LNG pressurized vaporization gas supply system, comprising a main liquid supply pipe (1), characterized in that: The main liquid supply pipe (1) is provided with a low-temperature stop valve (2), a filter (3), an LNG plunger pump (4), a check valve (5), a damper (6), a pressure transmitter (7), a low-temperature stop valve (8), an electric shut-off valve (9), an air-temperature vaporizer (10), a pressure gauge (11) and a temperature transmitter (12) in sequence along the LNG delivery direction; The main liquid supply pipe (1) between the second low-temperature stop valve (8) and the first electric shut-off valve (9) and the main liquid supply pipe (1) between the first air-temperature vaporizer (10) and the pressure gauge (11) are connected to the main vent pipe (14) through connecting pipes (13), and the two connecting pipes (13) are respectively installed with a safety valve (15) and a safety valve (16); It also includes a PLC control cabinet (17), and the LNG plunger pump (4), the electric shut-off valve (9), the pressure transmitter (7) and the temperature transmitter (12) are all electrically connected to the PLC control cabinet (17).

2. The LNG pressurized vaporization gas supply system according to claim 1, characterized in that: A liquid supply pipe (18) is connected in parallel to the main liquid supply pipe (1) at positions corresponding to the electric shut-off valve 1 (9) and the air-temperature type vaporizer 1 (10), and the electric shut-off valve 2 (19) and the air-temperature type vaporizer 2 (20) are sequentially installed on the liquid supply pipe (18) along the LNG delivery direction.

3. The LNG pressurized vaporization gas supply system according to claim 2, characterized in that: The second electric shut-off valve (19) is electrically connected to the PLC control cabinet (17).

4. The LNG pressurized vaporization gas supply system according to claim 2, characterized in that: The air-temperature vaporizer 1 (10) and the air-temperature vaporizer 2 (20) are both aluminum fin vaporizers formed by integral welding.

5. The LNG pressurized vaporization gas supply system according to claim 1, characterized in that: It also includes a combustible gas detector (21), wherein the combustible gas detector (21) is electrically connected to the PLC control cabinet (17).

6. The LNG pressurized vaporization gas supply system according to claim 1, characterized in that: It also includes an explosion-proof sound and light alarm (22), wherein the explosion-proof sound and light alarm (22) is electrically connected to the PLC control cabinet (17).

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