CN217816171U

CN217816171U - LNG gas supply system

Info

Publication number: CN217816171U
Application number: CN202222010362.1U
Authority: CN
Inventors: 王金成; 刘斌; 施伟佳
Original assignee: China International Marine Containers Group Co Ltd; CIMC Enric Holding Shenzhen Co Ltd; Jingmen Hongtu Special Aircraft Manufacturing Co Ltd
Current assignee: China International Marine Containers Group Co Ltd; CIMC Enric Holding Shenzhen Co Ltd; Jingmen Hongtu Special Aircraft Manufacturing Co Ltd
Priority date: 2022-07-28
Filing date: 2022-07-28
Publication date: 2022-11-15
Anticipated expiration: 2032-07-28

Abstract

The utility model provides a LNG gas supply system, it includes LNG storage tank, buffer tank and pressure release unit. The utility model discloses an among the LNG gas supply system, the buffer tank can realize keeping in of gaseous state LNG, realizes the stability to gaseous state LNG's pressure, temperature and flow before the use. Meanwhile, when the internal pressure of the LNG storage tank rises, the pressure relief unit in the LNG supply system can realize the storage of gaseous LNG in the buffer tank, so that the LNG storage tank gradually recovers normal safe pressure, and meanwhile, the situation that the gaseous LNG is discharged and relieved due to the take-off of the safety valve caused by the rise of the pressure is avoided, the zero emission of the whole LNG supply system is effectively guaranteed, and the LNG in the LNG storage tank can be efficiently utilized.

Description

LNG gas supply system

Technical Field

The utility model relates to a LNG utilizes technical field, in particular to LNG gas supply system.

Background

The LNG is used as fuel and has the advantages of cleanness, high efficiency, high heat value and the like. Due to the continuous perfection of LNG mining, storage and transportation technologies, LNG is widely used in various industries at present. LNG is increasingly accepted as the primary fuel in newly built gas turbine power generation projects.

LNG belongs to cryogenic medium, can not directly enter a gas turbine for combustion, and needs to be gasified and heated to be natural gas at normal temperature. The volume ratio of natural gas to LNG of the same mass is about 600, and natural gas is generally liquefied into LNG for storage in a storage tank. The operating mode difference between storage and the air feed makes no matter static or dynamic operating mode of LNG storage tank, all has the environment heat to leak into and leads to the circumstances of LNG gasification for pressure rise in the jar brings the safety risk, thereby leads to needing to discharge the pressure release, causes the loss.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve among the prior art LNG gas supply system, the environmental heat leaks into and leads to LNG gasification to cause the tank internal pressure to rise, and the system discharges the pressure release and causes the technical problem of loss.

In order to solve the technical problem, the utility model provides a LNG gas supply system which is used for supplying gaseous LNG to gas-using equipment and comprises a LNG storage tank, a buffer tank and a pressure relief unit, wherein the LNG storage tank is used for containing LNG; the LNG storage tank is provided with a liquid outlet and a gas phase port, and the liquid outlet and the gas phase port are both communicated with the interior of the LNG storage tank; the buffer tank is used for containing gaseous LNG and provided with a buffer inlet and a buffer outlet, the buffer inlet is communicated with a liquid outlet of the LNG storage tank through a pipeline, and the buffer outlet is used for being communicated with the gas-using equipment; the pressure relief unit comprises a pressure relief pipeline, and a pressure relief carburetor and a compressor which are arranged on the pressure relief pipeline; and the inlet of the pressure relief pipeline is communicated with the gas phase port of the LNG storage tank, and the outlet of the pressure relief pipeline is communicated with the buffer inlet of the buffer tank, so that gaseous LNG in the LNG storage tank enters the buffer tank through the temperature rise of the pressure relief vaporizer and the pressurization of the compressor.

Optionally, the LNG gas supply system further includes a storage tank pressure transmitter, and the storage tank pressure transmitter is disposed on the LNG storage tank and is configured to measure a pressure value signal inside the LNG storage tank; the LNG storage tank is provided with a gas phase valve, and the gas phase valve is arranged close to the gas phase port so as to open or close the gas phase port; the storage tank pressure transmitter is electrically connected with a controller of the LNG supply system so as to transmit the measured pressure value signal to the controller; the controller is electrically connected with the gas phase valve to control the opening or closing of the gas phase valve according to the pressure value signal.

Optionally, the pressure relief unit comprises two pressure relief vaporizers, and the two pressure relief vaporizers are arranged in parallel; the pressure relief unit comprises two compressors which are arranged in parallel.

Optionally, the gas supply system further comprises a liquid outlet unit, the liquid outlet unit comprises a pump pool, an immersed pump arranged in the pump pool, a liquid outlet vaporizer and a gas outlet pipeline, and the gas outlet pipeline is communicated between an outlet of the liquid outlet vaporizer and a buffer inlet of the buffer tank; an inlet of the pump pool is communicated with the liquid outlet through a pipeline, so that LNG in the LNG storage tank enters the pump pool; the immersed pump is communicated with an inlet of the liquid outlet vaporizer through a pipeline so as to pump the LNG in the pump pool into the liquid outlet vaporizer; the liquid outlet vaporizer vaporizes LNG into gaseous LNG, and the gaseous LNG is conveyed into the buffer tank through the gas outlet pipeline.

Optionally, the liquid outlet units are provided with two groups, the two groups of liquid outlet units are respectively a first liquid outlet unit and a second liquid outlet unit, and the first liquid outlet unit and the second liquid outlet unit are arranged in parallel; the number of the buffer tanks is two, and the two buffer tanks are respectively a first buffer tank and a second buffer tank; and the gas outlet pipeline in the first liquid outlet unit is communicated with the first buffer tank, and the gas outlet pipeline in the second liquid outlet unit is communicated with the second buffer tank.

Optionally, the liquid outlet unit further comprises a liquid outlet pressure transmitter, and the liquid outlet pressure transmitter is arranged on a pipeline between the immersed pump and the liquid outlet vaporizer and is used for measuring a pressure value signal of LNG entering the liquid outlet vaporizer; the liquid outlet pressure transmitter is electrically connected with a controller of the LNG supply system so as to transmit the measured pressure value signal to the controller; the controller is electrically connected with the immersed pump so as to control the frequency of the immersed pump according to the pressure value signal.

Optionally, the liquid outlet unit further comprises a liquid outlet temperature transmitter and a cut-off stop valve, and the cut-off stop valve is arranged on a pipeline between the immersed pump and the liquid outlet vaporizer; the liquid outlet temperature transmitter is arranged on the gas outlet pipeline and is used for measuring a temperature value signal of the gaseous LNG output by the liquid outlet vaporizer; the liquid outlet temperature transmitter is electrically connected with a controller of the LNG supply system so as to transmit the measured temperature value signal to the controller; the controller is electrically connected with the cut-off stop valve to control the cut-off stop valve to be opened or closed according to the temperature value signal, so that the on-off of a pipeline between the immersed pump and the liquid outlet vaporizer is controlled.

Optionally, the LNG gas supply system further comprises an unloading unit, wherein the unloading unit comprises an unloading liquid phase pipeline; the LNG storage tank is also provided with a storage tank liquid inlet, the unloading liquid phase pipe is communicated with an unloading liquid phase port of the LNG tank wagon and the storage tank liquid inlet, and the LNG tank wagon is also provided with an unloading gas phase port; the LNG gas supply system further comprises a pressurization gas phase pipeline, the inlet of the pressurization gas phase pipeline is communicated with the buffer outlet of the buffer tank, and the outlet of the pressurization gas phase pipeline is communicated with the unloading gas phase port.

Optionally, the unloading unit further comprises an unloading pressurization pipeline and an unloading pressurizer, and the LNG tanker is further provided with an unloading pressurization port; the unloading booster pipeline is communicated between an unloading booster port of the LNG tank car and an inlet of the unloading booster, and an outlet of the unloading booster is communicated with the unloading gas phase port through a pipeline, so that LNG in the LNG tank car enters the unloading booster, is gasified into gaseous LNG by the unloading booster, and enters the LNG tank car through the unloading gas phase port, and the LNG tank car is pressurized.

Optionally, the LNG storage tank is further provided with a storage tank air inlet, and the LNG gas supply system further comprises a pressurized gas phase pipeline; and the inlet of the pressurized gas phase pipeline is communicated with the buffer outlet of the buffer tank, and the outlet of the pressurized gas phase pipeline is communicated with the air inlet of the storage tank.

According to the above technical scheme, the beneficial effects of the utility model are that: the utility model discloses LNG gas supply system includes LNG storage tank, buffer tank and pressure release unit, and wherein, the buffer tank can realize keeping in of gaseous state LNG, realizes the stability to gaseous state LNG's pressure, temperature and flow before the use. Meanwhile, the pressure relief unit can realize the storage of the gaseous LNG in the buffer tank inside the LNG storage tank when the internal pressure of the LNG storage tank rises, so that the LNG storage tank gradually recovers normal safe pressure, and meanwhile, the situation that the gaseous LNG is discharged and relieved due to the take-off of the safety valve caused by the pressure rise is avoided, the zero emission of the whole LNG gas supply system is effectively guaranteed, and the LNG in the LNG storage tank can be efficiently utilized.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the LNG supply system of the present invention.

The reference numerals are explained below: 100. an LNG supply system; 10. an LNG storage tank; 11. a liquid outlet; 12. a gas phase port; 13. a top liquid inlet; 14. a bottom liquid inlet; 15. an air return port; 16. a storage tank pressure transmitter; 17. a gas phase valve; 20. a buffer tank; 201. a first buffer tank; 202. a second buffer tank; 21. a buffer inlet; 22. a buffer outlet; 30. a pressure relief unit; 31. a pressure relief pipeline; 32. a pressure relief vaporizer; 33. a compressor; 40. a piping unit; 41. a liquid phase main line; 42. a gas phase main pipeline; 43. a main return air line; 50. an unloading unit; 51. unloading the liquid phase pipeline; 52. unloading the booster pipeline; 53. unloading the supercharger; 60. a liquid outlet unit; 601. a first liquid outlet unit; 602. a second liquid outlet unit; 61. a pump pool; 611. a pump pool air port; 612. a pump pool liquid port; 62. an immersed pump; 63. a liquid outlet vaporizer; 64. an air outlet pipeline; 65. a liquid outlet pressure transmitter; 66. a liquid outlet temperature transmitter; 67. a liquid outlet cut-off stop valve; 70. a pressurized gas phase pipeline; 200. a gas using device; 301. unloading the liquid phase port; 302. unloading a pressurizing port; 303. and unloading the gas phase port.

Detailed Description

Exemplary embodiments that embody features and advantages of the present invention will be described in detail in the following description. It is to be understood that the invention is capable of other and different embodiments and its several details are capable of modification without departing from the scope of the invention, and that the description and drawings are to be regarded as illustrative in nature and not as restrictive.

In the description of the present application, it is to be understood that the indications of directions or positional relationships (such as up, down, left, right, front, rear, and the like) in the embodiments shown in the drawings are merely for convenience of description and simplicity of description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated. These illustrations are appropriate when the elements are in the positions shown in the figures. If the description of the positions of these elements changes, the indication of these directions changes accordingly.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

Referring to fig. 1, an embodiment of the present application provides an LNG gas supply system 100 for supplying gaseous LNG to a gas using facility 200. The LNG supply system 100 includes an LNG storage tank 10, a buffer tank 20, and a pressure relief unit 30.

Wherein, the inside LNG that is used for holding of LNG storage tank 10. LNG storage tank 10 is equipped with liquid outlet 11 and gaseous phase mouth 12, and liquid outlet 11 and gaseous phase mouth 12 all communicate with the inside of LNG storage tank 10. The buffer tank 20 is used for containing the gaseous LNG therein, and the buffer tank 20 is provided with a buffer inlet 21 and a buffer outlet 22. The buffer inlet 21 is connected to the liquid outlet 11 of the LNG storage tank 10 through a pipeline, and the buffer outlet 22 is used for being connected to the gas utilization apparatus 200.

The pressure relief unit 30 includes a pressure relief line 31, and a pressure relief carburetor 32 and a compressor 33 provided on the pressure relief line 31. An inlet of the pressure relief pipeline 31 is communicated with the gas phase port 12 of the LNG storage tank 10, and an outlet of the pressure relief pipeline 31 is communicated with the buffer inlet 21 of the buffer tank 20, so that the gaseous LNG in the LNG storage tank 10 enters the buffer tank 20 through the temperature rise of the pressure relief vaporizer 32 and the pressurization of the compressor 33.

In this embodiment, the LNG storage tank 10 is provided with a gas port 12, a liquid port 11, a liquid inlet, and a gas return port 15, which are communicated with the inside of the LNG storage tank 10. Wherein the gas phase port 12 is provided at the top of the LNG storage tank 10. The loading ports comprise a top loading port 13 arranged at the top of the LNG tank 10 and a bottom loading port 14 arranged at the bottom of the LNG tank 10. The liquid outlet 11 is disposed at the bottom of the LNG storage tank 10, and the gas return port 15 is disposed at the top of the LNG storage tank 10.

The LNG supply system 100 of the present embodiment further includes a piping unit 40, and the piping unit 40 includes a liquid-phase main line 41, a gas-phase main line 42, and a gas-return main line 43.

In this embodiment, the LNG supply system 100 further includes an unloading unit 50, and the unloading unit 50 is used for unloading the LNG tank to the LNG storage tank 10. The unloading unit 50 includes an unloading liquid phase line 51, an unloading booster line 52, and an unloading booster 53. The LNG tank wagon is provided with a discharge liquid phase port 301, a discharge pressurization port 302 and a discharge gas phase port 303.

The inlet of the unloading liquid phase pipeline 51 is communicated with the unloading liquid phase port 301, and the top liquid inlet 13 and the bottom liquid inlet 14 of the LNG storage tank 10 are respectively communicated with the unloading liquid phase pipeline 51 through pipelines. A low-temperature stop valve and a low-temperature starting cut-off stop valve are arranged on a pipeline between the top liquid inlet 13 and the unloading liquid phase pipeline 51 so as to control the on-off of the pipeline. A low-temperature stop valve and a low-temperature starting and cutting-off stop valve are arranged on a pipeline between the bottom liquid inlet 14 and the unloading liquid phase pipeline 51 so as to control the on-off of the pipeline.

The unloading liquid phase pipeline 51 is communicated with the unloading liquid phase port 301 and the top liquid inlet 13 and the bottom liquid inlet 14 of the LNG storage tank 10, LNG in the LNG tank wagon can enter the LNG storage tank 10 through the unloading liquid phase pipeline 51, the top liquid inlet 13 and the bottom liquid inlet 14, and accordingly liquid unloading of the LNG tank wagon into the LNG storage tank 10 is achieved.

In the present embodiment, the outlet of the gas phase main pipeline 42 is communicated with the unloading gas phase port 303 of the LNG tanker, and the gas phase port 12 of the LNG tank 10 is communicated with the gas phase main pipeline 42 through a pipeline. The unloading pressurization line 52 communicates between the unloading pressurization port 302 of the LNG tanker and the inlet of the unloading pressurizer 53 to allow LNG in the LNG tanker to enter the unloading pressurizer 53 and be vaporized into gaseous LNG in the unloading pressurizer 53.

The outlet of the unloading booster 53 is communicated with the gas phase main pipeline 42 through a pipeline to be communicated with the unloading gas phase port 303 of the LNG tank wagon through the gas phase main pipeline 42, so that the gas-state LNG enters the LNG tank wagon, and the pressure inside the LNG tank wagon is increased. The internal pressure of the LNG tank wagon rises, and a pressure difference can be formed between the LNG tank wagon and the LNG storage tank 10, so that LNG in the LNG tank wagon can be rapidly and efficiently introduced into the LNG storage tank 10 through the unloading liquid phase pipeline 51, thereby improving the unloading efficiency.

Further, the LNG supply system 100 of the present embodiment further includes a liquid outlet unit 60, and the liquid outlet unit 60 includes a pump pool 61, an immersed pump 62 disposed in the pump pool 61, a liquid outlet vaporizer 63, and a gas outlet pipeline 64.

The pump sump 61 is provided with a pump sump air port 611 and a pump sump liquid port 612. In the present embodiment, the outlet of the liquid-phase main pipeline 41 is communicated with the inlet of the pump sump 61, and the liquid outlet 11 of the LNG storage tank 10 is communicated with the liquid-phase main pipeline 41 through a pipeline, so that the LNG in the LNG storage tank 10 can enter the pump sump 61 through the liquid-phase main pipeline 41.

The immersed pump 62 is communicated with the inlet of the liquid outlet vaporizer 63 through a pipeline, and the outlet of the liquid outlet vaporizer 63 is communicated with the buffer inlet 21 of the buffer tank 20 through a gas outlet pipeline 64.

The immersed pump 62 pumps the LNG in the pump pool 61 into the liquid outlet vaporizer 63, the liquid outlet vaporizer 63 vaporizes the LNG into gaseous LNG, the gaseous LNG enters the buffer tank 20 through the gas outlet pipeline 64, temporary storage of the gaseous LNG in the buffer tank 20 is realized, and the buffer tank 20 can stabilize the pressure, temperature and flow rate of the gaseous LNG.

In this embodiment, a thermometer and a temperature transmitter are disposed on the buffer tank 20, so that a worker can monitor the temperature of the gaseous LNG inside the buffer tank 20 in real time. Still be equipped with manometer and pressure transmitter on buffer tank 20 to make the pressure condition of the inside gaseous state LNG of buffer tank 20 of staff real-time supervision.

The liquid outlet unit 60 of this embodiment further includes a liquid outlet pressure transmitter 65, the liquid outlet pressure transmitter 65 is disposed on the pipeline between the immersed pump 62 and the liquid outlet vaporizer 63, and the liquid outlet pressure transmitter 65 is configured to measure a pressure value signal of the LNG entering the liquid outlet vaporizer 63.

The liquid outlet pressure transmitter 65 is electrically connected to the controller of the LNG supply system 100 to transmit the measured pressure value signal to the controller. The controller is electrically connected to the immersed pump 62 to control the frequency of the immersed pump 62 based on the received pressure value signal measured by the effluent pressure transmitter 65 so that the pressure of the LNG pumped by the immersed pump 62 into the effluent vaporizer 63 is within the allowable fluctuation range.

In addition, the liquid outlet unit 60 further includes an outlet temperature transmitter 66 and an outlet shutoff valve 67. Wherein, a liquid outlet cut-off valve 67 is provided on the piping between the immersed pump 62 and the liquid outlet vaporizer 63. A liquid outlet temperature transmitter 66 is arranged on the gas outlet line 64 for measuring the temperature value signal of the gaseous LNG outputted by the liquid outlet vaporizer 63.

The liquid outlet temperature transmitter 66 is electrically connected with a controller in the LNG supply system 100 to transmit a measured temperature value signal of the gaseous LNG output from the liquid outlet vaporizer 63 to the controller, and the controller is electrically connected with the liquid outlet cut-off valve 67 to control the opening or closing of the liquid outlet cut-off valve 67 according to the temperature value signal, thereby controlling the opening and closing of the pipeline between the immersed pump 62 and the liquid outlet vaporizer 63.

When the controller receives the temperature value signal of the gaseous LNG outputted from the boil-off vaporizer 63 measured by the boil-off temperature transmitter 66 and analyzes that the temperature of the gaseous LNG outputted from the boil-off vaporizer 63 reaches a set temperature, the controller controls the boil-off cutoff valve 67 to open so that the LNG pumped out by the immersed pump 62 can enter the boil-off vaporizer 63.

The gas-using apparatus 200 of the present embodiment is a gas turbine, and the buffer outlet 22 of the buffer tank 20 is connected to the gas turbine through a pipeline, so that the gaseous LNG in the buffer tank 20 can enter the gas turbine and be used by the gas turbine. In other examples, the gas-using apparatus 200 may be a plant fuel apparatus, a backup fuel apparatus, a natural gas automobile, or the like, in addition to a gas turbine.

Further, one end of the return air main line 43 of the present embodiment communicates with the sump air port 611 of the sump 61, and the return air port 15 of the LNG tank 10 communicates with the return air main line 43 through a pipe.

In this embodiment, two sets of liquid outlet units 60 are provided, and the two sets of liquid outlet units 60 are respectively a first liquid outlet unit 601 and a second liquid outlet unit 602. The first liquid outlet unit 601 and the second liquid outlet unit 602 both comprise a pump pool 61, an immersed pump 62 arranged in the pump pool 61, a liquid outlet vaporizer 63 and a gas outlet pipeline 64. The first liquid outlet unit 601 and the second liquid outlet unit 602 are arranged in parallel.

The buffer tanks 20 of the present embodiment are also provided in two, and the two buffer tanks 20 are a first buffer tank 201 and a second buffer tank 202, respectively. The outlet pipeline 64 in the first liquid outlet unit 601 is communicated with the buffer inlet 21 of the first buffer tank 201, and the outlet pipeline 64 in the second liquid outlet unit 602 is communicated with the buffer inlet 21 of the second buffer tank 202.

By arranging two sets of liquid outlet units 60 and two buffer tanks 20, the purpose of one use and one standby can be realized, thereby ensuring the stability of the whole LNG supply system 100.

Further, the pressure relief unit 30 of the present embodiment includes a pressure relief line 31, and a pressure relief vaporizer 32 and a compressor 33 provided on the pressure relief line 31.

In this embodiment, an inlet of the pressure relief pipeline 31 is communicated with the gas phase main pipeline 42 to communicate with the gas phase port 12 of the LNG storage tank 10, and an outlet of the pressure relief pipeline 31 is communicated with the gas outlet pipeline 64 to enable the gaseous LNG in the LNG storage tank 10 to enter the buffer tank 20 through the pressure relief pipeline 31.

During the operation of the LNG storage tank 10, gaseous LNG gradually accumulates inside the LNG storage tank 10, so that the pressure inside the LNG storage tank 10 rises. The pressure relief pipe 31 is provided with a pressure relief carburetor 32 and a compressor 33. The gaseous LNG in the LNG storage tank 10 can enter the pressure relief vaporizer 32 through the pressure relief pipeline 31 to be heated, and then enter the buffer tank 20 after being pressurized to a set pressure value by the compressor 33.

In the present embodiment, the LNG storage tank 10 is provided with a gas phase valve 17, and the gas phase valve 17 is disposed near the gas phase port 12 to open or close the gas phase. The LNG tank 10 is provided with a tank pressure transmitter 16, and the tank pressure transmitter 16 of the LNG tank 10 is electrically connected to a controller of the LNG gas supply system 100 to transmit a signal indicating a measured pressure value inside the LNG tank 10 to the controller. The controller is electrically connected to the gas phase valve 17 to control the opening or closing of the gas phase valve 17 according to the pressure value signal.

When the controller receives the pressure value signal transmitted by the storage tank pressure transmitter 16 and analyzes that the pressure value inside the LNG storage tank 10 is greater than the set working pressure and less than the safe discharge pressure, the controller controls the gas phase valve 17 to open, and the gaseous LNG in the LNG storage tank 10 enters the pressure relief pipeline 31 through the gas phase main pipeline 42 and enters the buffer tank 20 through the temperature rise of the pressure relief vaporizer 32 and the pressurization of the compressor 33.

The pressure relief unit 30 of the LNG gas supply system 100 of this embodiment can realize the storage of the gaseous LNG inside the LNG storage tank 10 in the buffer tank 20 when the internal pressure of the LNG storage tank 10 rises, so that the LNG storage tank 10 gradually recovers the normal safety pressure, and meanwhile, the condition that the take-off of the safety valve leads to the discharge and pressure relief of the gaseous LNG due to the pressure rise is also avoided, thereby effectively ensuring the zero emission of the whole LNG gas supply system 100, and ensuring that the LNG in the LNG storage tank 10 can be efficiently utilized.

In this embodiment, the pressure relief unit 30 includes two pressure relief vaporizers 32, and the two pressure relief vaporizers 32 are arranged in parallel. The pressure relief unit 30 comprises two compressors 33, the two compressors 33 being arranged in parallel. Two pressure relief vaporizers 32 are provided as one use and two compressors 33 are provided as one use and one use, thereby stably ensuring zero discharge of the LNG feed system 100.

Further, the LNG supply system 100 of the present embodiment further includes a pressurized gas phase pipeline 70. An inlet of the pressurized gas phase line 70 communicates on a line between the buffer outlet 22 of the buffer tank 20 and the gas using device 200 to communicate with the buffer outlet 22. The outlet of the pressurized gas phase line 70 communicates on the gas phase main line 42 to communicate with the unloading gas phase port 303 of the LNG tanker.

By providing the pressurized gas phase line 70, the unloading booster 53 and the unloading booster line 52 can be omitted from the unloading unit 50, and the structure of the LNG gas supply system 100 can be simplified. The pressurized gas phase pipeline 70 can lead the gaseous LNG in the buffer tank 20 into the LNG tank wagon to pressurize the internal pressure of the LNG tank wagon, thereby improving the unloading efficiency.

In the present embodiment, the pressurized gas-phase pipeline 70 is connected to the gas-phase main pipeline 42 and can also be connected to the gas-phase port 12 of the LNG tank 10 through the gas-phase main pipeline 42, so that the gaseous LNG in the buffer tank 20 can enter the LNG tank 10 through the pressurized gas-phase pipeline 70 and the gas-phase main pipeline 42, and thus the LNG in the LNG tank 10 can be smoothly discharged when the internal pressure of the LNG tank 10 is too low.

For the LNG gas supply system of the present embodiment, it includes an LNG storage tank, a buffer tank, and a pressure relief unit. The buffer tank can realize the temporary storage of gaseous state LNG, realizes the stability to gaseous state LNG's pressure, temperature and flow before using. Meanwhile, the pressure relief unit can realize the storage of the gaseous LNG in the buffer tank inside the LNG storage tank when the internal pressure of the LNG storage tank rises, so that the LNG storage tank gradually recovers normal safe pressure, and meanwhile, the situation that the gaseous LNG is discharged and relieved due to the take-off of the safety valve caused by the pressure rise is avoided, the zero emission of the whole LNG gas supply system is effectively guaranteed, and the LNG in the LNG storage tank can be efficiently utilized.

While the present invention has been described with reference to several exemplary embodiments, it is understood that the terminology used is intended to be in the nature of words of description and illustration, rather than of limitation. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.

Claims

1. An LNG supply system for supplying gaseous LNG to a gas-using facility, the LNG supply system comprising:

the LNG storage tank is used for containing LNG inside; the LNG storage tank is provided with a liquid outlet and a gas phase port, and the liquid outlet and the gas phase port are both communicated with the interior of the LNG storage tank;

the buffer tank is internally used for containing gaseous LNG and provided with a buffer inlet and a buffer outlet, the buffer inlet is communicated with a liquid outlet of the LNG storage tank through a pipeline, and the buffer outlet is used for being communicated with the gas-using equipment;

the pressure relief unit comprises a pressure relief pipeline, and a pressure relief carburetor and a compressor which are arranged on the pressure relief pipeline; the inlet of the pressure relief pipeline is communicated with the gas phase port of the LNG storage tank, and the outlet of the pressure relief pipeline is communicated with the buffer inlet of the buffer tank, so that the gaseous LNG in the LNG storage tank enters the buffer tank through the temperature rise of the pressure relief vaporizer and the pressurization of the compressor.

2. The LNG gas supply system according to claim 1, further comprising a storage tank pressure transmitter provided on the LNG storage tank for determining a pressure value signal inside the LNG storage tank; the LNG storage tank is provided with a gas phase valve, and the gas phase valve is arranged close to the gas phase port so as to open or close the gas phase port;

the storage tank pressure transmitter is electrically connected with a controller of the LNG supply system so as to transmit the measured pressure value signal to the controller; the controller is electrically connected with the gas phase valve to control the opening or closing of the gas phase valve according to the pressure value signal.

3. The LNG gas supply system according to claim 1, wherein the pressure relief unit comprises two pressure relief vaporizers arranged in parallel; the pressure relief unit comprises two compressors which are arranged in parallel.

4. The LNG supply system according to claim 1, wherein the gas supply system further comprises a liquid outlet unit, the liquid outlet unit comprises a pump pool, an immersed pump disposed in the pump pool, a liquid outlet vaporizer, and a gas outlet pipeline, the gas outlet pipeline is communicated between an outlet of the liquid outlet vaporizer and a buffer inlet of the buffer tank;

an inlet of the pump pool is communicated with the liquid outlet through a pipeline, so that LNG in the LNG storage tank enters the pump pool; the immersed pump is communicated with an inlet of the liquid outlet vaporizer through a pipeline so as to pump the LNG in the pump pool into the liquid outlet vaporizer; the liquid outlet vaporizer vaporizes LNG into gaseous LNG, and the gaseous LNG is conveyed into the buffer tank through the gas outlet pipeline.

5. The LNG gas supply system according to claim 4, wherein the liquid outlet units are provided in two groups, the two groups of liquid outlet units are a first liquid outlet unit and a second liquid outlet unit, and the first liquid outlet unit and the second liquid outlet unit are arranged in parallel;

the number of the buffer tanks is two, and the two buffer tanks are respectively a first buffer tank and a second buffer tank; and the gas outlet pipeline in the first liquid outlet unit is communicated with the first buffer tank, and the gas outlet pipeline in the second liquid outlet unit is communicated with the second buffer tank.

6. The LNG supply system of claim 4, wherein the tapping unit further comprises a tapping pressure transmitter disposed on a pipeline between the immersed pump and the tapping vaporizer for determining a pressure value signal of the LNG entering the tapping vaporizer; the liquid outlet pressure transmitter is electrically connected with a controller of the LNG supply system so as to transmit the measured pressure value signal to the controller; and the controller is electrically connected with the immersed pump so as to control the frequency of the immersed pump according to the pressure value signal.

7. The LNG supply system according to claim 4, wherein the liquid outlet unit further includes a liquid outlet temperature transmitter and a cut-off valve provided on a pipeline between the immersed pump and the liquid outlet vaporizer; the liquid outlet temperature transmitter is arranged on the gas outlet pipeline and is used for measuring a temperature value signal of the gaseous LNG output by the liquid outlet vaporizer;

the liquid outlet temperature transmitter is electrically connected with a controller of the LNG supply system so as to transmit the measured temperature value signal to the controller; the controller is electrically connected with the cut-off stop valve to control the cut-off stop valve to be opened or closed according to the temperature value signal, so that the on-off of a pipeline between the immersed pump and the liquid outlet vaporizer is controlled.

8. The LNG gas supply system of claim 1, further comprising an unloading unit comprising an unloading liquid phase pipeline; the LNG storage tank is also provided with a storage tank liquid inlet, the unloading liquid phase pipe is communicated with an unloading liquid phase port of the LNG tank wagon and the storage tank liquid inlet, and the LNG tank wagon is also provided with an unloading gas phase port;

the LNG gas supply system further comprises a pressurization gas phase pipeline, the inlet of the pressurization gas phase pipeline is communicated with the buffer outlet of the buffer tank, and the outlet of the pressurization gas phase pipeline is communicated with the unloading gas phase port.

9. The LNG supply system of claim 8, wherein the unloading unit further comprises an unloading pressurization pipeline and an unloading pressurizer, and the LNG tank wagon is further provided with an unloading pressurization port;

the unloading booster pipeline is communicated between an unloading booster port of the LNG tank car and an inlet of the unloading booster, and an outlet of the unloading booster is communicated with the unloading gas phase port through a pipeline, so that LNG in the LNG tank car enters the unloading booster, is gasified into gaseous LNG by the unloading booster, and enters the LNG tank car through the unloading gas phase port, and the LNG tank car is pressurized.

10. The LNG gas supply system according to claim 1, wherein the LNG storage tank is further provided with a storage tank gas inlet, the LNG gas supply system further comprising a pressurized gas phase pipeline; and the inlet of the pressurized gas phase pipeline is communicated with the buffer outlet of the buffer tank, and the outlet of the pressurized gas phase pipeline is communicated with the air inlet of the storage tank.