CN212748494U

CN212748494U - LNG online sampling and cold insulation device

Info

Publication number: CN212748494U
Application number: CN202021519380.7U
Authority: CN
Inventors: 李德刚; 吕晓翠; 于松涛; 秦克胜; 杨朋飞; 谢腾腾; 白珍龙
Original assignee: China National Offshore Oil Corp CNOOC; CNOOC Petrochemical Engineering Co Ltd; CNOOC Oil and Petrochemicals Co Ltd
Current assignee: China National Offshore Oil Corp CNOOC; CNOOC Petrochemical Engineering Co Ltd; CNOOC Oil and Petrochemicals Co Ltd
Priority date: 2020-07-28
Filing date: 2020-07-28
Publication date: 2021-03-19
Anticipated expiration: 2030-07-28

Abstract

The utility model belongs to the technical field of LNG online sampling, and discloses an LNG online sampling and cold insulation device, which comprises a cold insulation circulating pipe, a sampling pipe, a jacket valve, a first connecting pipe and a second connecting pipe, wherein one end of the cold insulation circulating pipe is communicated with a main pipeline, the sampling pipe is arranged in the cold insulation circulating pipe in a penetrating way, one end of the main pipeline is communicated with the main pipeline, the other end of the main pipeline is communicated with the vaporizer, LNG in the main pipeline can flow through the sampling pipe to enter the vaporizer, the jacket valve is arranged on the sampling pipe, the LNG in the main pipeline can sequentially flow through the cold insulation circulating pipe, the first connecting pipe, the jacket valve and the second connecting pipe to flow back into the main pipeline. The device can ensure that LNG is kept in a supercooled state before vaporization.

Description

LNG online sampling and cold insulation device

Technical Field

The utility model belongs to the technical field of the online sample of LNG, especially, relate to an online sample cold insulation of LNG device.

Background

In the LNG (liquefied natural gas) trade, LNG components need to be measured, and a gas chromatograph is generally used for analysis, and LNG needs to be converted into normal temperature gas so as to meet the analysis requirements of the gas chromatograph. For the on-line sampling of LNG, the key to the successful detection is to ensure that the gas sample after sampling and vaporization is consistent with the liquid components. ISO8943 requires that the LNG sample must be kept in a subcooled, i.e. fully liquid, state prior to vaporization, and that no fractional vaporization of any components occurs, which would result in a deviation of the sample entering the on-line analysis system and sample collection system from the actual sample. However, the conventional static cold insulation mode has limited cold insulation effect, and fractionation and vaporization still occur.

Therefore, an LNG online sampling and cold insulation device is needed to solve the above technical problems.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an LNG online sampling cold insulation device can guarantee that the LNG sample remains the full liquid state all the time before the vaporization, and no fractionation vaporization takes place to effectively improve the probability that detects successfully.

To achieve the purpose, the utility model adopts the following technical proposal:

an LNG online sampling cold insulation device comprises:

one end of the cold insulation circulating pipe is communicated with the main pipeline;

the sampling pipe penetrates through the cold insulation circulating pipe, one end of the sampling pipe is communicated with the main pipeline, the other end of the sampling pipe is communicated with the vaporizer, and LNG in the main pipeline can flow through the sampling pipe and enter the vaporizer;

the jacket valve is arranged on the sampling tube and used for controlling the opening and closing of the sampling tube, and the jacket valve is connected to the other end of the cold insulation circulating tube;

one end of the first connecting pipe is communicated with the cold insulation circulating pipe, and the other end of the first connecting pipe is communicated with one interface of the jacket valve;

and one end of the second connecting pipe is communicated with the other interface of the jacket valve, the other end of the second connecting pipe is communicated with the main pipeline, and the LNG in the main pipeline can sequentially flow through the cold insulation circulating pipe, the first connecting pipe, the jacket valve and the second connecting pipe and then flow back into the main pipeline so as to carry out cold insulation on the LNG in the sampling pipe.

Preferably, an inlet thermometer is disposed at an interface where the jacket valve is connected to the first connection pipe, and the inlet thermometer is configured to detect a temperature of the LNG flowing into the jacket valve.

Preferably, an outlet thermometer is arranged at a joint of the jacket valve and the second connecting pipe, and the outlet thermometer is used for detecting the temperature of the LNG flowing out of the jacket valve.

Preferably, the cold insulation circulation pipe is a double-layer pipe, a space between an inner pipe and an outer pipe of the double-layer pipe is a reflux layer, the sampling pipe penetrates through the inner pipe, a space between the inner pipe and the sampling pipe is a cooling layer, the LNG can flow into the cooling layer from the main pipeline, flows through the reflux layer and flows back into the main pipeline, and the first connection pipe is communicated with the cooling layer.

Preferably, the sampling tube further comprises a cold insulation part, the cold insulation part comprises a vacuum sleeve, the vacuum sleeve is connected to one end, away from the cold insulation circulating tube, of the jacket valve, and the vacuum sleeve is sleeved on the sampling tube.

Preferably, a heat insulation layer is arranged between the vacuum sleeve and the sampling tube.

Preferably, the outer walls of the sampling tube corresponding to the two ends of the vacuum casing are respectively provided with a first thermometer and a second thermometer.

Preferably, the vacuum sleeve is provided with an evacuation valve and a vacuum transmitter, the vacuum transmitter is used for measuring the vacuum degree in the vacuum sleeve, and the evacuation valve is used for adjusting the vacuum degree in the vacuum sleeve.

Preferably, the BOG system further comprises a third connecting pipe, one end of the third connecting pipe is communicated with the second connecting pipe, the other end of the third connecting pipe is communicated with the BOG system, a safety valve is arranged on the third connecting pipe, and the safety valve is used for safely emptying when the second connecting pipe is in overpressure.

Preferably, the cold insulation circulating pipe, the jacket valve, the first connecting pipe and the second connecting pipe are coated with heat insulation layers.

The utility model has the advantages that:

the utility model provides an LNG online sampling cold insulation device, wherein, the overcooled LNG in the main pipeline flows into a vaporizer through a sampling tube, and is vaporized by the vaporizer for detection; the super-cooled LNG can flow into the cold insulation circulating pipe, and the sampling pipe is arranged in the cold insulation circulating pipe in a penetrating mode, so that the super-cooled LNG flows out of the wall of the sampling pipe; the jacket valve arranged on the sampling tube can control the opening and closing of the sampling tube, supercooling LNG flows between the sampling tube and the outer wall of the jacket valve, when the pressure in the sampling tube drops suddenly or the cold insulation efficiency is reduced, the fractionation phenomenon occurs to the external LNG, the phase change enthalpy of the external LNG reduces the external temperature, and the supercooling degree of the LNG in the sampling tube is effectively ensured. The utility model provides a LNG online sampling cold insulation device can guarantee that the LNG sample remains the full liquid state before the vaporization throughout, and no fractionation vaporization takes place to effectively improve the probability that detects successfully.

Drawings

Fig. 1 is a cross-sectional view of the online sampling and cold insulation device for LNG provided by the embodiment of the present invention.

In the figure:

10. a main pipeline;

1. a cold insulation circulating pipe; 2. a jacket valve; 3. a first connecting pipe; 4. a second connecting pipe; 5. a sampling tube; 8. a BOG system; 9. a heat-insulating layer;

11. a cooling layer; 12. a reflow layer; 61. an inlet thermometer; 62. an outlet thermometer; 71. a vacuum bushing; 72. a thermal insulation layer; 73. a first thermometer; 74. a second thermometer; 75. an evacuation valve; 76. and a vacuum transmitter.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar parts throughout, or parts having the same or similar functions. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "mounted" are to be construed broadly and can include, for example, both fixed and removable connections, mechanical and electrical connections, direct connections, indirect connections through an intermediary, communication between two elements, or an interaction between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the description of the present invention, unless otherwise expressly specified or limited, the first feature "on" or "under" the second feature may include both the first and second features being in direct contact, and may also include the first and second features being in contact, not in direct contact, but with another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The technical solution of the present invention is further explained by the following embodiments with reference to the accompanying drawings.

As shown in fig. 1, the present embodiment provides an LNG online sampling and cold insulation device, which includes a cold insulation circulation pipe 1, a sampling pipe 5, a jacket valve 2, a first connection pipe 3 and a second connection pipe 4, wherein one end of the cold insulation circulation pipe 1 is communicated with a main pipeline 10; the sampling pipe 5 is arranged in the cold insulation circulating pipe 1 in a penetrating mode, one end of the sampling pipe 5 is communicated with the main pipeline 10, the other end of the sampling pipe 5 is communicated with the vaporizer, and LNG in the main pipeline 10 can flow through the sampling pipe 5 and enter the vaporizer; the jacket valve 2 is arranged on the sampling tube 5 and used for controlling the opening and closing of the sampling tube 5, and the jacket valve 2 is connected to the other end of the cold insulation circulating tube 1; one end of the first connecting pipe 3 is communicated with the cold insulation circulating pipe 1, and the other end is communicated with one interface of the jacket valve 2; one end of the second connecting pipe 4 is communicated with the other interface of the jacket valve 2, the other end is communicated with the main pipeline 10, and LNG in the main pipeline 10 can sequentially flow through the cold insulation circulating pipe 1, the first connecting pipe 3, the jacket valve 2 and the second connecting pipe 4 to flow back into the main pipeline 10 so as to carry out cold insulation on the LNG in the sampling pipe 5.

In the LNG online sampling and cold insulation device provided by this embodiment, the supercooled LNG in the main pipeline 10 flows into the vaporizer through the sampling tube 5, and is vaporized by the vaporizer and then detected; the supercooled LNG can flow into the cold insulation circulating pipe 1, and the sampling pipe 5 is arranged in the cold insulation circulating pipe 1 in a penetrating mode, so the supercooled LNG flows out of the wall of the sampling pipe 5; the jacket valve 2 arranged on the sampling tube 5 can control the opening and closing of the sampling tube 5, supercooling LNG flows between the sampling tube 5 and the outer wall of the jacket valve 2, when the pressure in the sampling tube 5 drops suddenly or the cooling efficiency is reduced, fractionation phenomenon of the external LNG occurs, the phase change enthalpy of the external LNG reduces the external temperature, and the supercooling degree of the LNG in the sampling tube 5 is effectively ensured. The LNG online sampling cold insulation device provided by the embodiment can ensure that an LNG sample is always in a full liquid state before vaporization, no fractionation vaporization occurs, and therefore the probability of successful detection is effectively improved.

As shown in fig. 1, the second connection pipe 4 is connected to the downstream of the main pipeline 10, so as to prevent the LNG returned from the second connection pipe 4 to the main pipeline 10 from entering the cold insulation circulation pipe 1 and the sampling pipe 5, and ensure that the LNG flowing into the cold insulation circulation pipe 1 and the sampling pipe 5 is in a supercooled state.

Specifically, an inlet thermometer 61 is provided at an interface of the jacket valve 2 connected to the first connection pipe 3, for detecting the temperature of the LNG flowing into the jacket valve 2. An outlet thermometer 62 is arranged at the interface of the jacketed valve 2 connected to the second connecting pipe 4 and used for detecting the temperature of the LNG flowing out of the jacketed valve 2. The inlet thermometer 61 and the outlet thermometer 62 can observe the temperature change before entering the vaporizer from the jacket valve 2 at any time, so that whether the LNG is flashed or not can be judged.

Specifically, cold insulation circulating pipe 1 is the double-deck pipe, and the space between the inner tube of double-deck pipe and the outer tube is reflux layer 12, and the inner tube is worn to locate by sampling tube 5, and the space between inner tube and sampling tube 5 is cooling layer 11, and LNG can flow into cooling layer 11 from main line 10, flows through reflux layer 12 backward flow and goes into main line 10, and first connecting pipe 3 communicates in cooling layer 11. LNG in the cooling layer 11 keeps cold to the LNG in the sampling tube 5, and the backward flow layer 12 forms the return circuit with the 11 intercommunication of cooling layer for the dynamic supercooling LNG that flows in all the time in the cooling layer 11. In this embodiment, the first connecting tube 3 is communicated with one end of the cooling layer 11 away from the main pipeline 10, and the LNG flowing out of the cooling layer 11 is divided into two branches, and flows into the first connecting tube 3 and the reflux layer 12 respectively, so as to cool different positions of the sampling tube 5 respectively.

The online sampling cold insulation device of LNG that this embodiment provided still includes cold insulation spare, and cold insulation spare includes vacuum sleeve 71, and vacuum sleeve 71 connects in the one end that presss from both sides sleeve valve 2 and deviates from cold insulation circulating pipe 1, and vacuum sleeve 71 cover is located sampling tube 5. The vacuum casing 71 is in a vacuum state, does not have a heat conduction condition, and can continuously cool the LNG in the sampling tube 5, thereby ensuring the supercooled state of the LNG.

In particular, a thermal insulation layer 72 is provided between the vacuum sleeve 71 and the sampling tube 5. In this embodiment, a plurality of layers of overlapped thermal insulation layers 72 are provided, the thermal insulation layers 72 are made of super thermal insulation materials, the super thermal insulation materials are existing materials in the field, and the detailed components are not described herein.

Optionally, a first thermometer 73 and a second thermometer 74 are respectively disposed on the outer wall of the sampling tube 5 corresponding to the two ends of the vacuum casing 71. The first thermometer 73 and the second thermometer 74 are provided to facilitate the observation and judgment of the flash vaporization of LNG before the LNG is introduced from the vacuum jacket 71 to the vaporizer.

Specifically, the vacuum casing 71 is provided with an evacuation valve 75 and a vacuum transducer 76, the vacuum transducer 76 being used to measure the degree of vacuum in the vacuum casing 71, and the evacuation valve 75 being used to adjust the degree of vacuum in the vacuum casing 71. First, the vacuum degree in the vacuum casing 71 can be measured by using the vacuum transducer 76, and when the vacuum degree cannot meet the requirement, the vacuum degree in the vacuum casing 71 can be adjusted by externally connecting the vacuum pump to the evacuation valve 75, so as to ensure that the required vacuum state is achieved in the vacuum casing 71.

The online sampling cold insulation device of LNG that this embodiment provided still includes the third connecting pipe, and the one end of third connecting pipe communicates in second connecting pipe 4, and the other end communicates in BOG system 8, is provided with the relief valve on the third connecting pipe, and the relief valve is used for carrying out safe unloading when the 4 superpressures of second connecting pipe. When the flash evaporation appears in the LNG that circulates between jacket valve 2 and the

sampling tube

5, 4 pressure on the second connecting pipe rises, and the relief valve will open automatically, and the LNG of flash evaporation passes through the third connecting pipe and gets into BOG system 8, and BOG system 8 is used for the liquefaction to handle the flash evaporation vapour, and prior art can be referred to its concrete structure and theory of operation, and no longer repeated here.

Specifically, the cold insulation circulating pipe 1, the jacket valve 2, the first connecting pipe 3, the second connecting pipe 4, the vacuum sleeve 71 and the main pipeline 10 are coated with the heat insulation layer 9, so that the cold insulation effect is further achieved. In the present embodiment, the cold insulation circulation pipe 1 is connected to the main pipeline 10 by a flange, and both ends of the jacket valve 2 are respectively connected to the vacuum jacket 71 and the cold insulation circulation pipe 1 by a flange.

It is obvious that the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. The utility model provides a LNG online sampling cold insulation device which characterized in that includes:

a cold insulation circulating pipe (1), one end of which is communicated with the main pipeline (10);

the sampling pipe (5) is arranged in the cold insulation circulating pipe (1) in a penetrating mode, one end of the sampling pipe (5) is communicated with the main pipeline (10), the other end of the sampling pipe is communicated with the vaporizer, and LNG in the main pipeline (10) can flow through the sampling pipe (5) and enter the vaporizer;

the jacket valve (2) is arranged on the sampling pipe (5) and used for controlling the opening and closing of the sampling pipe (5), and the jacket valve (2) is connected to the other end of the cold insulation circulating pipe (1);

one end of the first connecting pipe (3) is communicated with the cold insulation circulating pipe (1), and the other end of the first connecting pipe is communicated with one interface of the jacket valve (2);

one end of the second connecting pipe (4) is communicated with the other interface of the jacket valve (2), the other end of the second connecting pipe is communicated with the main pipeline (10), and the LNG in the main pipeline (10) can sequentially flow through the cold insulation circulating pipe (1), the first connecting pipe (3), the jacket valve (2) and the second connecting pipe (4) and flow back into the main pipeline (10) so as to carry out cold insulation on the LNG in the sampling pipe (5).

2. LNG online sampling cold insulation according to claim 1, characterized in that an inlet thermometer (61) is provided at the interface of the jacket valve (2) connected to the first connection pipe (3), the inlet thermometer (61) being used for detecting the temperature of the LNG flowing into the jacket valve (2).

3. LNG online sampling cold insulation according to claim 1, characterized in that an outlet thermometer (62) is provided at the interface of the jacket valve (2) to the second connection pipe (4), the outlet thermometer (62) being used to detect the temperature of the LNG flowing out of the jacket valve (2).

4. The LNG online sampling and cold insulation device of claim 1, wherein the cold insulation circulation pipe (1) is a double-layer pipe, a space between an inner pipe and an outer pipe of the double-layer pipe is a reflux layer (12), the sampling pipe (5) is arranged in the inner pipe in a penetrating manner, a space between the inner pipe and the sampling pipe (5) is a cooling layer (11), the LNG can flow into the cooling layer (11) from the main pipeline (10), flows through the reflux layer (12) and flows back into the main pipeline (10), and the first connection pipe (3) is communicated with the cooling layer (11).

5. The LNG online sampling and cold insulation device according to claim 1, further comprising a cold insulation member, wherein the cold insulation member comprises a vacuum sleeve (71), the vacuum sleeve (71) is connected to an end of the jacket valve (2) facing away from the cold insulation circulation pipe (1), and the vacuum sleeve (71) is sleeved on the sampling pipe (5).

6. LNG online sampling cold insulation according to claim 5, characterized in that a thermal insulation layer (72) is arranged between the vacuum sleeve (71) and the sampling tube (5).

7. The LNG online sampling and cold insulation device according to claim 5, characterized in that the sampling tube (5) is provided with a first thermometer (73) and a second thermometer (74) at the outer walls corresponding to the two ends of the vacuum casing (71), respectively.

8. LNG online sampling cold insulation according to claim 5, characterized in that the vacuum casing (71) is provided with an evacuation valve (75) and a vacuum transducer (76), the vacuum transducer (76) is used for measuring the vacuum degree in the vacuum casing (71), and the evacuation valve (75) is used for adjusting the vacuum degree in the vacuum casing (71).

9. The on-line LNG sampling and cold insulation device of claim 1, further comprising a third connection pipe, one end of the third connection pipe is connected to the second connection pipe (4), the other end of the third connection pipe is connected to the BOG system (8), and a safety valve is disposed on the third connection pipe and used for safety venting when the second connection pipe (4) is over-pressurized.

10. The LNG online sampling and cold insulation device according to any one of claims 1 to 9, wherein the cold insulation circulation pipe (1), the jacket valve (2), the first connection pipe (3) and the second connection pipe (4) are coated with an insulation layer (9).