Air separation backup liquid nitrogen storage tank cold energy recovery system

Abstract

The utility model relates to the technical field of nitrogen cooling capacity recovery, and solves the problem that products and carried cooling capacity are wasted due to the fact that nitrogen is directly discharged into the atmosphere. The air separation backup liquid nitrogen storage tank cold energy recovery system comprises a water cooling system, a nitrogen storage tank, a nitrogen storage tank, a nitrogen storage tank and a nitrogen storage tank, the water cooling system comprises a liquid nitrogen storage tank which is connected with a water cooling tower through a circulation pipeline, and emptying low-temperature nitrogen in the liquid nitrogen storage tank is conveyed to the water cooling tower and guides cooling capacity separation in the water cooling tower. The gas conveying device is in butt joint with the water cooling tower and guides nitrogen to be output outwards, the gas conveying device comprises a nitrogen storage tank, an output end and an input end, the output end and the input end are arranged on the nitrogen storage tank, the input end is connected with a gas conveying pipe for establishing a gas conveying channel between the water cooling tower and the nitrogen storage tank, and an outlet of the nitrogen storage tank is connected with a nitrogen compressor; the output end of the nitrogen compressor is connected with an output channel and a backflow channel which is connected with the output channel and flows back to the nitrogen storage tank.

Description

Technical Field

[0001] The utility model relates to the technical field of nitrogen cooling capacity recovery, in particular to a cooling capacity recovery system for an air separation backup liquid nitrogen storage tank. Background Art

[0002] Most domestic air separation systems today are equipped with backup systems. During normal operation, a portion of the liquid product is stored in a backup tank. If the unit shuts down for some reason, the backup system can be immediately operational to avoid disrupting the normal operation of subsequent units. If a subsequent unit experiences an abnormality, the unit can also adjust operating conditions to produce liquid product. For safety reasons, the backup liquid nitrogen storage tank must be equipped with a pressure-controlled venting device, which allows some nitrogen to enter the atmosphere, also removing some of the cooling capacity. Utility Model Content

[0003] In order to address the deficiencies of the prior art, the present invention provides a cold recovery system for an air separation backup liquid nitrogen storage tank, which solves the problem of waste of product and carried cold energy when nitrogen is directly discharged into the atmosphere.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a cold recovery system for an air separation backup liquid nitrogen storage tank, comprising:

[0005] A water cooling system that blocks the nitrogen flow path and displaces the cold energy present in the nitrogen;

[0006] The water cooling system includes a liquid nitrogen storage tank for storing liquid nitrogen, the liquid nitrogen storage tank is connected to a water cooling tower through a circulation pipeline, and the low-temperature nitrogen discharged from the liquid nitrogen storage tank is transported to the water cooling tower and guides the cooling capacity to be released in the water cooling tower;

[0007] The gas transmission device is connected to the water cooling tower and guides the nitrogen to be output outward. It includes a nitrogen storage tank and an output end and an input end arranged on the nitrogen storage tank. The input end is connected to a gas transmission pipe that establishes a gas transmission channel between the water cooling tower and the nitrogen storage tank. The outlet of the nitrogen storage tank is connected to a nitrogen compressor. The output end of the nitrogen compressor is connected to an output channel and a reflux channel connected to the output channel and refluxes to the nitrogen storage tank.

[0008] In one embodiment, a coil heat exchanger is provided in the water cooling tower, and a flow pipe is connected to the gas transmission pipe. One end of the coil heat exchanger is used for the entry of low-temperature nitrogen and the connection of nitrogen output. The water cooling tower is filled with chilled water, and the height of the coil heat exchanger is set lower than the liquid level of the chilled water.

[0009] The connection height between the circulation pipeline and the coil heat exchanger is greater than the connection height between the gas transmission pipe and the coil heat exchanger.

[0010] In one embodiment, the liquid nitrogen storage tank includes a tank body and an outlet channel provided on the tank body for connecting with a circulation pipeline to guide the low-temperature nitrogen to move toward the water cooling tower. A stop valve is installed on the outlet channel to establish or release the transmission of low-temperature nitrogen to the water cooling tower.

[0011] In one embodiment, the input end of the nitrogen storage tank is arranged at both ends thereof, and the gas pipe transports the vaporized nitrogen into the nitrogen storage tank through the input end located on the left side. The input end on the same side as the output end is arranged above the output end, the reflux channel is connected to the input end on the same side as the output end, and the gas pipeline is connected at the output end.

[0012] In one embodiment, a limit liquid level alarm is installed at one end of the tank body and the water cooling tower.

[0013] In one embodiment, the output channel guides the nitrogen gas to be discharged into the nitrogen pipeline network and then delivered to subsequent production equipment.

[0014] Compared with the existing technology, the utility model provides a cold recovery system for an air separation backup liquid nitrogen storage tank, which has the following beneficial effects:

[0015] In the technical solution disclosed by the utility model, the liquid nitrogen stored in the liquid nitrogen storage tank is exchanged with heat in the water cooling tower. On the one hand, the residual cold can be effectively stripped from the low-temperature nitrogen, thereby enhancing the recovery and utilization of the cold. On the other hand, the recovered cold is used to lower the temperature of the chilled water in the water cooling tower, thereby reducing the amount of cold supply required for the intervention of an external refrigerator, shortening the working time of the refrigerator, saving production electricity, and reducing production costs.

[0016] When the nitrogen gas that has completed heat exchange and vaporized is transported outward from the nitrogen storage tank through the utility model, a reflux channel is set up on its transport track, and the reflux channel returns to the nitrogen storage tank through the reflux valve, which is used to control the outlet flow and pressure of the nitrogen compressor, ensure the normal operation of the compressor, and enhance the overall operation stability of the recovery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0018] Figure 1 This is a schematic diagram of the overall structure of the utility model;

[0019] Figure 2 This is a schematic diagram of the structure of the water cooling system of the utility model;

[0020] Figure 3 This is a schematic structural diagram of the gas transmission device of the present utility model.

[0021] In the figure: 1. Water cooling system; 11. Liquid nitrogen storage tank; 110. Tank body; 111. Gas outlet channel; 12. Circulation pipeline; 13. Water cooling tower; 14. Coil heat exchanger; 2. Gas transmission device; 21. Nitrogen storage tank; 22. Output end; 23. Input end; 24. Gas transmission pipe; 25. Output channel; 26. Reflux channel; 27. Nitrogen compressor. DETAILED DESCRIPTION

[0022] The following will describe the implementation methods of the present application in detail with reference to the accompanying drawings and examples, so that the implementation process of how the present application applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0023] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0024] Figure 1-Figure 3 This is an embodiment of the present invention. The specific problem addressed by this specific embodiment is that most domestic air separation systems are equipped with backup systems. When the air separation unit is in normal production, a portion of the liquid product is stored in the backup storage tank. When the air separation unit is shut down for some reason, the backup system can be put into use immediately to avoid affecting the normal production of the subsequent units. When abnormal changes occur in the subsequent units, the air separation unit can also adjust the operating conditions to produce liquid products. For safety reasons, the backup liquid nitrogen storage tank 11 must be equipped with a pressure-controlled venting device, which allows a portion of the nitrogen to enter the atmosphere and also takes away a portion of the cooling capacity. Based on the above purpose of recovering cooling capacity in nitrogen, this solution proposes an air separation backup liquid nitrogen storage tank cooling capacity recovery system, which exchanges the low-temperature nitrogen discharged from the liquid nitrogen storage tank 11 with heat in the water cooling tower 13. On the one hand, it can effectively strip off the residual cold from the discharged low-temperature nitrogen and enhance the recovery and utilization of cold. On the other hand, it can use the recovered cold to lower the temperature of the chilled water in the water-cooling tower 13, reduce the amount of cold supply required for the intervention of an external refrigerator, shorten the working time of the refrigerator, save production electricity, and reduce production costs.

[0025] The disclosed air separation backup liquid nitrogen storage tank cold recovery system specifically includes: a water cooling system 1 and a gas transmission device 2, wherein the water cooling system 1 is used to cut off the nitrogen flow path and replace the cold energy in the nitrogen. Specifically, a liquid nitrogen storage tank 11 is connected to a water cooling tower 13 through a flow pipe 12. The discharged low-temperature nitrogen in the liquid nitrogen storage tank 11 is transported to the water cooling tower 13 and the cold energy is guided to be separated in the water cooling tower 13. The gas transmission device 2 is used to guide the nitrogen to be output outward through its connection with the water cooling tower 13. After passing through the water cooling tower 13, the low-temperature nitrogen exchanges heat with the chilled water in the water cooling tower 13, thereby consuming the cold energy of the low-temperature nitrogen itself and exchanging it with the chilled water to complete the cold energy recovery in the low-temperature nitrogen. A coil-type water bath vaporizer is added to the water cooling tower 13. During the heat exchange process, the nitrogen is guided to the gas transmission device 2 until it is separated from the gas transmission device 2.

[0026] The water cooling system 1 includes a liquid nitrogen storage tank 11 for storing liquid nitrogen. The liquid nitrogen storage tank 11 includes a tank body 110 and an outlet channel 111 provided on the tank body 110 for connecting with a flow pipeline 12 to guide the liquid nitrogen therein to move toward a water cooling tower 13. A stop valve is installed on the outlet channel 111 to establish or terminate the transmission of low-temperature nitrogen to the water cooling tower 13. One end of the tank body 110 and the water cooling tower 13 are both equipped with a limit liquid level alarm to monitor the low-temperature nitrogen and chilled water levels therein.

[0027] A coil heat exchanger 14 is provided in the water-cooling tower 13, and the circulation pipeline 12 is connected to the gas pipeline 24. One end of the coil heat exchanger 14 is used for the entry of low-temperature nitrogen and the connection of nitrogen output. The water-cooling tower 13 is filled with chilled water, and the height of the coil heat exchanger 14 is set lower than the liquid level of the chilled water, so that the coil heat exchanger 14 is completely immersed in the chilled water, that is, the chilled water wraps the low-temperature nitrogen filled in the coil heat exchanger 14, thereby increasing the heat exchange area between it and the low-temperature nitrogen and increasing the heat exchange efficiency. On the other hand, the connection height of the circulation pipeline 12 and the coil heat exchanger 14 is greater than the connection height of the gas pipeline 24 and the coil heat exchanger 14. During the heat exchange process, when the low-temperature nitrogen is separated from the cooling capacity, based on the setting of the front and rear pressure difference, the nitrogen enters the gas pipeline 24.

[0028] The gas delivery device 2 includes a nitrogen storage tank 21 and an output end 22 and an input end 23 provided on the nitrogen storage tank 21. The input end 23 of the nitrogen storage tank 21 is provided at both ends thereof, and the input end 23 on the same side as the output end 22 is provided above the output end 22. A gas delivery pipe 24 delivers vaporized nitrogen into the nitrogen storage tank 21 through the input end 23 located on the left side. The input end 23 is connected to a gas delivery pipe 24 that establishes a gas delivery channel between the water cooling tower 13 and the nitrogen storage tank 21. The outlet of the nitrogen storage tank 21 is connected to a nitrogen compressor 27. The output end of the nitrogen compressor is connected to an output channel 25 and a reflux channel 26 that is connected to the output channel 25 and refluxes back to the nitrogen storage tank 21. The reflux channel 26 is connected to the input end 23 on the same side as the output end 22, and the gas delivery pipe 24 is connected to the output end 22. The output channel 25 guides the nitrogen gas out into the nitrogen pipeline network for subsequent production equipment. When the nitrogen storage tank 21 transports the vaporized nitrogen after heat exchange, a reflux channel 26 is set up on its transport track. The reflux channel 26 returns to the nitrogen storage tank 21 through the reflux valve, and is used to control the outlet flow and pressure of the nitrogen compressor 27 to ensure the normal operation of the compressor and enhance the overall operation stability of the recovery system.

[0029] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0030] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A cold recovery system for an air separation backup liquid nitrogen storage tank, characterized in that: include: A water cooling system (1) that blocks the nitrogen flow path and replaces the cold energy in the nitrogen; The water cooling system (1) includes a liquid nitrogen storage tank (11) for storing liquid nitrogen. The liquid nitrogen storage tank (11) is connected to a water cooling tower (13) via a circulation pipeline (12). Low-temperature nitrogen discharged from the liquid nitrogen storage tank (11) is transported to the water cooling tower (13) and guided to release cold energy in the water cooling tower (13). A gas transmission device (2) is connected to a water cooling tower (13) and guides nitrogen to be output outward. The gas transmission device (2) comprises a nitrogen storage tank (21), an output end (22) and an input end (23) arranged on the nitrogen storage tank (21). The input end (23) is connected to a gas transmission pipe (24) for establishing a gas transmission channel between the water cooling tower (13) and the nitrogen storage tank (21). The outlet of the nitrogen storage tank (21) is connected to a nitrogen compressor (27). The outlet of the nitrogen compressor (27) is connected to an output channel (25) and a reflux channel (26) connected to the output channel (25) and refluxed to the nitrogen storage tank (21).

2. A cold recovery system according to claim 1, characterized in that: The water cooling tower (13) is provided with a coil heat exchanger (14), and the circulation pipeline (12) is connected to the gas transmission pipe (24) at one end of the coil heat exchanger (14) for the entry of low-temperature nitrogen and the connection of nitrogen output. The water cooling tower (13) is filled with chilled water, and the height of the coil heat exchanger (14) is set less than the height of the chilled water liquid level. The connection height between the circulation pipeline (12) and the coil-type heat exchanger (14) is greater than the connection height between the gas transmission pipe (24) and the coil-type heat exchanger (14).

3. The cold recovery system according to claim 1, characterized in that: The liquid nitrogen storage tank (11) comprises a tank body (110) and an outlet passage (111) provided on the tank body (110) and used for connecting with a circulation pipeline (12) to guide low-temperature nitrogen to move toward a water-cooling tower (13). A stop valve is installed on the outlet passage (111) to establish or release the transmission of low-temperature nitrogen to the water-cooling tower (13).

4. The cold recovery system according to claim 1, characterized in that: The input end (23) of the nitrogen storage tank (21) is arranged at both ends thereof, and the gas delivery pipe (24) delivers the vaporized nitrogen into the nitrogen storage tank (21) through the input end (23) located on the left side. The input end (23) on the same side as the output end (22) is arranged above the output end (22). The reflux channel (26) is connected to the input end (23) on the same side as the output end (22), and the gas delivery pipe (24) is connected to the output end (22).

5. The cold recovery system according to claim 3, characterized in that: One end of the tank body (110) and the water cooling tower (13) are both equipped with a limit liquid level alarm.

6. The cold recovery system according to claim 4, characterized in that: The output channel (25) guides the nitrogen to be discharged into the nitrogen pipe network and then fed into subsequent production equipment.

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