A precooling device for LNG pipeline

Abstract

The utility model discloses a precooling device for LNG pipelines. The utility model relates to the technical field of the precooling device structure, which includes a base, a buffer tank fixed on the top surface of the base, an air inlet main pipeline and an air outlet main pipeline are fixed on the top and on the left and right sides of the buffer tank, respectively, and a bend connected to the air inlet main pipeline is connected to the left port; a vaporization manifold for vaporizing liquid nitrogen is respectively arranged on the base and on the front and rear sides of the buffer tank, and the vaporization manifold located on the front side of the buffer tank includes a liquid nitrogen input pipe and a nitrogen output pipe; a plurality of liquid nitrogen branch pipes are connected to the liquid nitrogen input pipe at intervals along its length direction, and the left port of the nitrogen output pipe is connected to the bottom port of the bend pipe; a plurality of nitrogen branch pipes corresponding to the liquid nitrogen branch pipes are connected to the nitrogen output pipe along its length direction. The beneficial effects of the utility model are: improving the precooling efficiency and preventing the LNG pipeline from being damaged.

Description

Technical Field

[0001] The utility model relates to the technical field of precooling device structures, in particular to a precooling device for an LNG pipeline. Background Art

[0002] At present, with the increasing demand for natural gas energy, liquid natural gas (LNG) has begun to be imported from abroad in large quantities, and the number of corresponding LNG receiving stations built on land has also gradually increased. The LNG receiving station is used to receive LNG transported from cargo ships. An LNG pipeline is connected between the LNG receiving station and the cargo ship, and the LNG exported from the cargo ship is transported through the LNG pipeline.

[0003] Due to the low temperature of LNG, the LNG pipeline must be pre-cooled by a pre-cooling device [if LNG is directly introduced into the LNG pipeline, it will cause damage to the LNG pipeline, causing a greater safety hazard]. The working principle of the pre-cooling device used in a certain area is: first, the low-temperature liquid nitrogen in the tank truck is vaporized into low-temperature nitrogen through a vaporizer, and then the vaporizer passes the low-temperature nitrogen into the LNG pipeline. The low-temperature nitrogen pre-cools the LNG pipeline. After working for a period of time, the LNG pipeline can be pre-cooled.

[0004] However, although this precooling device can be used, it still has the following technical defects:

[0005] I. The precooling device is only equipped with one vaporizer, which results in insufficient amount of low-temperature nitrogen input into the LNG pipeline, which in turn requires a long time to cool the entire LNG pipeline to the required temperature, and there is a technical defect of low precooling efficiency.

[0006] II. The low-temperature nitrogen vaporized by the vaporizer also contains some liquid nitrogen, and when the liquid nitrogen is introduced into the LNG pipeline, it will cause damage to the LNG pipeline.

[0007] III. During the precooling process, when the low-temperature nitrogen input into the LNG pipeline is too low, the LNG pipeline will be damaged, and this precooling device cannot control the temperature of the low-temperature nitrogen input into the LNG pipeline. Therefore, a precooling device that improves the precooling efficiency and prevents damage to the LNG pipeline is urgently needed. Utility Model Content

[0008] The utility model aims to overcome the shortcomings of the prior art and provide a precooling device for an LNG pipeline which can improve the precooling efficiency and prevent the LNG pipeline from being damaged.

[0009] The purpose of the utility model is achieved through the following technical solutions: a precooling device for an LNG pipeline, which includes a base, a buffer tank fixedly mounted on the top surface of the base, an inlet main pipeline and an outlet main pipeline are fixedly mounted on the top and left and right sides of the buffer tank, a temperature gauge and a pressure detector are sequentially connected to the end of the outlet main pipeline, and a bend pipe connected to the left end of the inlet main pipeline is connected to the left end of the inlet main pipeline;

[0010] A vaporization manifold for vaporizing liquid nitrogen is respectively arranged on the base and located at the front and rear sides of the buffer tank, and the vaporization manifold located at the front side of the buffer tank includes a liquid nitrogen input pipe and a nitrogen output pipe; the liquid nitrogen input pipe is connected to a plurality of liquid nitrogen branch pipes at intervals along its length direction, each of which is connected to a valve A, and the left port of the nitrogen output pipe is connected to the bottom port of the elbow; the nitrogen output pipe is connected to a plurality of nitrogen branch pipes corresponding to the liquid nitrogen branch pipes along its length direction, each of which is connected to a valve B;

[0011] The left end of the buffer tank is connected with a bending pipe and a stop valve in sequence, the bending pipe is communicated with the buffer tank, and the other end of the stop valve is connected with a normal temperature nitrogen storage tank.

[0012] The two vaporization manifolds are symmetrically arranged front and rear of the buffer tank.

[0013] A ball valve is arranged on the bent pipe.

[0014] The diameter of the liquid nitrogen branch pipe is smaller than the diameter of the nitrogen branch pipe.

[0015] The nitrogen output pipe is arranged at the rear side of the liquid nitrogen input pipe, and an opening and closing valve is connected at the head end of the liquid nitrogen input pipe.

[0016] A cabinet located on the left side of the buffer tank is arranged on the base.

[0017] The cabinet is electrically connected to the ball valve, valve A, valve B, ball valve, opening and closing valve, temperature gauge and pressure detector via signal lines.

[0018] The utility model has the following advantages: improving precooling efficiency and preventing LNG pipeline from being damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the utility model;

[0020] Figure 2 for Figure 1 The structural diagram without the cabinet is shown in FIG.

[0021] Figure 3 for Figure 1 The main view;

[0022] Figure 4 for Figure 1 A top view of

[0023] Figure 5 A schematic diagram for connecting multiple carburetors;

[0024] In the figure:

[0025] 1- base, 2- buffer tank, 3- air inlet main pipe, 4- air outlet main pipe, 5- temperature gauge, 6- pressure detector, 7- elbow;

[0026] 8-vaporization manifold, 9-liquid nitrogen input pipe, 10-nitrogen output pipe, 11-liquid nitrogen branch pipe, 12-valve A, 13-nitrogen branch pipe, 14-valve B;

[0027] 15-bending pipe, 16-stop valve, 17-opening and closing valve, 18-cabinet, 19-vaporizer. DETAILED DESCRIPTION

[0028] The utility model is further described below in conjunction with the accompanying drawings, and the protection scope of the utility model is not limited to the following:

[0029] like Figure 1~Figure 4 As shown, a precooling device for an LNG pipeline comprises a base 1, a buffer tank 2 fixedly mounted on the top surface of the base 1, an inlet main pipeline 3 and an outlet main pipeline 4 are fixedly mounted on the top and on the left and right sides of the buffer tank 2, a thermometer 5 and a pressure detector 6 are sequentially connected to the end of the outlet main pipeline 4, a bend pipe 7 connected to the left end of the inlet main pipeline 3 is connected to the bend pipe 7, and a ball valve is arranged on the bend pipe 7;

[0030] The base 1 is provided with vaporization manifolds 8 for vaporizing liquid nitrogen on the front and rear sides of the buffer tank 2, respectively. The two vaporization manifolds 8 are symmetrically arranged about the front and rear sides of the buffer tank 2. The vaporization manifold 8 located on the front side of the buffer tank 2 includes a liquid nitrogen input pipe 9 and a nitrogen output pipe 10; the liquid nitrogen input pipe 9 is connected with a plurality of liquid nitrogen branch pipes 11 at intervals along its length direction, each of which is connected with a valve A12, and the left port of the nitrogen output pipe 10 is connected with the bottom port of the elbow 7; the nitrogen output pipe 10 is connected with a plurality of nitrogen branch pipes 13 corresponding to the liquid nitrogen branch pipes 11 along its length direction, each of which is connected with a valve B14; the diameter of the liquid nitrogen branch pipe 11 is smaller than the diameter of the nitrogen branch pipe 13.

[0031] The left end of the buffer tank 2 is connected with a bending pipe 15 and a stop valve 16 in sequence. The bending pipe 15 is in communication with the buffer tank 2, and the other end of the stop valve 16 is connected with a normal temperature nitrogen storage tank.

[0032] The nitrogen output pipe 10 is arranged at the rear side of the liquid nitrogen input pipe 9, and the head end of the liquid nitrogen input pipe 9 is connected with an on-off valve 17. The base 1 is provided with a cabinet 18 located on the left side of the buffer tank 2, and the cabinet 18 is electrically connected with the ball valve, valve A12, valve B14, ball valve, on-off valve 17, thermometer 5 and pressure detector 6 via a signal line. The cabinet 18 can control the start or close of the ball valve, valve A12, valve B14, ball valve and on-off valve 17, thereby facilitating the operation of the workers, and the thermometer 5 can feed back the temperature signal of the low-temperature nitrogen to the cabinet 18 in real time.

[0033] The working process of the utility model is as follows:

[0034] S1. A worker connects the end port of the pressure detector 6 on the main gas outlet pipeline 4 to the LNG pipeline;

[0035] S2. A worker connects a vaporizer 19 between the end of the liquid nitrogen branch pipe 11 on the front vaporization manifold 8 and the first end of the nitrogen branch pipe 13;

[0036] S3, the worker repeats the operation of step S2 for several times, and then connects a vaporizer 19 between the end port of each liquid nitrogen branch pipe 11 and the first port of the nitrogen branch pipe 13, such as Figure 5 As shown;

[0037] S4. The worker connects the pipeline on the liquid nitrogen tank truck to the left port of the liquid nitrogen input pipe 9; opens the on-off valve 17, each valve A12 and each valve B14 at the head end of the liquid nitrogen input pipe 9; opens the valve on the liquid nitrogen tank truck. At this time, the liquid nitrogen in the liquid nitrogen tank truck is under pressure and passes through the left port of the liquid nitrogen input pipe 9, the on-off valve 17, the liquid nitrogen input pipe 9, the liquid nitrogen branch pipe 11, and finally enters the vaporizer 19. The vaporizer 19 vaporizes the liquid nitrogen entering therein into low-temperature nitrogen. The low-temperature nitrogen passes through the nitrogen branch pipe 13, the nitrogen output pipe 10, the elbow 7, the ball valve, the air inlet main pipe 3, and finally enters the buffer tank 2. Among them, when the nitrogen enters the buffer tank 2, part of the liquid nitrogen entrained in the nitrogen falls to the bottom of the buffer tank 2, and the dry low-temperature nitrogen passes through the air outlet main pipe 4, the thermometer 5, and the pressure detector 6 in sequence, and finally enters the LNG pipeline. The low-temperature nitrogen precools the LNG pipeline;

[0038] It can be seen from step S4 that after the nitrogen enters the buffer tank 2, part of the liquid nitrogen entrained in the nitrogen has fallen to the bottom of the buffer tank 2, ensuring that the low-temperature nitrogen entering the LNG pipeline is always dry. Therefore, compared with the existing precooling device, the precooling device effectively avoids damage to the LNG pipeline.

[0039] S5. During the precooling process, the thermometer 5 detects the temperature of the low-temperature nitrogen discharged from the buffer tank 2 in real time, and transmits the temperature signal to the cabinet in real time. If the cabinet detects that the temperature is too low, the cabinet 18 controls the stop valve 16 to open, and the normal temperature nitrogen in the normal temperature nitrogen storage tank passes through the stop valve 16 and the bending pipe 15 in sequence under air pressure, and finally enters the buffer tank 2. After the normal temperature nitrogen enters the buffer tank 2, it mixes with the low temperature nitrogen, thereby increasing the temperature of the low temperature nitrogen, thereby controlling the temperature of the low temperature nitrogen to be input into the LNG pipeline to avoid damage to the LNG pipeline; when the thermometer 5 detects that the temperature of the low temperature nitrogen discharged from the buffer tank 2 returns to the set temperature, the cabinet 18 controls the stop valve 16 to close;

[0040] S6. When the LNG pipeline is precooled to the set temperature, close the valve on the liquid nitrogen tank truck, disconnect the pipeline on the liquid nitrogen tank truck from the left port of the liquid nitrogen input pipe 9, and then close valve A12, valve B14, ball valve and on-off valve 17.

[0041] Among them, it can be seen from steps S2~S3 that since multiple vaporizers 19 can be connected to one vaporization manifold 8, the output of nitrogen is increased, and the entire LNG pipeline can be cooled to the required temperature in a short time. Compared with a precooling device with only one vaporizer, the precooling efficiency of the LNG pipeline is greatly improved.

[0042] Finally, it should be noted that the above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A precooling device for an LNG pipeline, characterized in that: It comprises a base (1), a buffer tank (2) fixedly mounted on the top surface of the base (1), an air inlet main pipe (3) and an air outlet main pipe (4) fixedly mounted on the top and left and right sides of the buffer tank (2), a temperature gauge (5) and a pressure detector (6) being connected in sequence at the end of the air outlet main pipe (4), and a bend pipe (7) connected thereto being connected to the left end of the air inlet main pipe (3); A vaporization manifold (8) for vaporizing liquid nitrogen is respectively arranged on the base (1) and located at the front and rear sides of the buffer tank (2), and the vaporization manifold (8) located at the front side of the buffer tank (2) comprises a liquid nitrogen input pipe (9) and a nitrogen output pipe (10); the liquid nitrogen input pipe (9) is connected to a plurality of liquid nitrogen branch pipes (11) at intervals along its length direction, and each liquid nitrogen branch pipe (11) is connected to a valve A (12); the left end of the nitrogen output pipe (10) is connected to the bottom end of the elbow (7); the nitrogen output pipe (10) is connected to a plurality of nitrogen branch pipes (13) corresponding to the liquid nitrogen branch pipes (11) along its length direction, and each nitrogen branch pipe (13) is connected to a valve B (14); The left end of the buffer tank (2) is connected in sequence to a bent pipe (15) and a stop valve (16); the bent pipe (15) is in communication with the buffer tank (2); and the other end of the stop valve (16) is connected to a normal temperature nitrogen storage tank.

2. The precooling device for LNG pipeline according to claim 1, characterized in that: The two vaporization manifolds (8) are symmetrically arranged front and rearwardly with respect to the buffer tank (2).

3. The precooling device for LNG pipeline according to claim 2, characterized in that: A ball valve is provided on the curved pipe (7).

4. The precooling device for LNG pipeline according to claim 3, characterized in that: The diameter of the liquid nitrogen branch pipe (11) is smaller than the diameter of the nitrogen branch pipe (13).

5. The precooling device for LNG pipeline according to claim 4, characterized in that: The nitrogen output pipe (10) is arranged at the rear side of the liquid nitrogen input pipe (9), and an opening and closing valve (17) is connected to the head end of the liquid nitrogen input pipe (9).

6. The precooling device for LNG pipeline according to claim 5, characterized in that: The base (1) is provided with a cabinet (18) located on the left side of the buffer tank (2).

7. The precooling device for LNG pipeline according to claim 6, characterized in that: The cabinet (18) is electrically connected to the ball valve, valve A (12), valve B (14), the ball valve, the on-off valve (17), the temperature gauge (5) and the pressure detector (6) via signal lines.

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