Liquid nitrogen cold energy recovery system

Abstract

The utility model relates to a liquid nitrogen cooling capacity recovery system. The device comprises a liquid nitrogen storage tank, a water bath type vaporizer, an air bath type vaporizer, a secondary refrigerant storage tank, an ethylene oxide storage tank and an ice maker system, and the outlet end of the liquid nitrogen storage tank is connected with the liquid nitrogen inlet end of the water bath type vaporizer through a first liquid nitrogen branch and connected with the inlet end of the air bath type vaporizer through a second liquid nitrogen branch. The outlet end of the air bath type vaporizer is connected with nitrogen using equipment through a nitrogen tail end conveying pipe; the nitrogen outlet end of the water bath type vaporizer is connected with the inlet end of the air bath type vaporizer through a nitrogen middle conveying pipe. During normal operation, liquid nitrogen in the liquid nitrogen storage tank sequentially passes through the water bath type vaporizer and the air bath type vaporizer for heat exchange, and the water bath type vaporizer, a heat exchange jacket of the ethylene oxide storage tank and the secondary refrigerant storage tank form a closed circulation pipeline of the secondary refrigerant. When the conditions such as abnormal temperature of the secondary refrigerant occur in the water bath type vaporizer, the bypass technological process can be used for vaporization of the liquid nitrogen and circulation of the refrigerant in the ethylene oxide storage tank.

Description

Technical Field

[0001] The utility model relates to a liquid nitrogen cold energy recovery system, belonging to the technical field of production systems for preparing nitrogen by vaporizing liquid nitrogen. Background Art

[0002] In the industrial field, liquid nitrogen can be used for deep refrigeration, and the nitrogen gas generated by its vaporization can be used as a protective gas. Most enterprises use air-cooled vaporizers to vaporize liquid nitrogen into nitrogen gas. During the vaporization process of liquid nitrogen, a large amount of cold energy is generated when the temperature rises from -196°C to normal temperature. If this cold energy is directly discharged into the air, it will cause energy waste. Therefore, in the prior art, it is usually considered to jointly use the cooling water in the air-cooled vaporizer and other cooling water using equipment. For example, the Chinese patent document with the publication number CN220870613U discloses a liquid nitrogen cold energy recovery device, which includes a liquid nitrogen storage tank. The gas outlet of the liquid nitrogen storage tank is connected in parallel with a water bath vaporization unit and a vaporizer. The exhaust ports of the water bath vaporization unit and the vaporizer are combined and connected to the upstream of a control valve group. The downstream of the control valve group is sequentially connected in series with a flow meter and a nitrogen gas tank; the water bath vaporization unit includes a water path and a gas path; the inlet of the water path is communicated with a water collector, and the outlet of the water path is communicated with a water distributor; the inlet of the gas path is communicated with the liquid nitrogen storage tank, and the outlet of the gas path is communicated with the control valve group; through the return water pressure of the water collector, the inlet water enters the inner cavity of the box body, and a temperature probe detects the water temperature. If it meets the requirements of chilled water, the liquid in the inner cavity of the box body is pumped by a water pump, drawn into the inner cavity of the water distributor and provided for other equipment to use. If not, the liquid nitrogen in the inner cavity of the liquid nitrogen storage tank enters the inner cavity of the box body from the air inlet of the vaporization device, and is discharged from the air outlet of the vaporization device into the inner cavity of the nitrogen gas tank. During the process of liquid nitrogen to nitrogen gas, a large amount of cold energy is absorbed, and the liquid in the inner cavity of the box body also absorbs a large amount of cold energy until the chilled water temperature is reached, and then the liquid in the inner cavity of the box body is pumped by a water pump into the inner cavity of the water distributor, so as to be provided for other equipment to use. However, in this scheme, it does not consider how other equipment that requires chilled water can operate normally when the chilled water in the water collector does not meet the requirements; in addition, the vaporizer in this scheme is idle for a long time, and only when the water bath vaporization unit is under maintenance, the vaporizer will be started for temporary work, and the equipment utilization efficiency is low. Content of the Utility Model

[0003] The technical problem to be solved by the utility model is to provide a liquid nitrogen cold energy recovery system with higher equipment utilization efficiency, which is more conducive to ensuring the normal operation of the pipeline system for preparing nitrogen from liquid nitrogen and other equipment for recovering and utilizing liquid nitrogen cold energy.

[0004] The technical solution adopted by the present utility model to solve the above technical problems is as follows: a liquid nitrogen cold energy recovery system, including a liquid nitrogen storage tank, a water-bath vaporizer, an air-bath vaporizer, a coolant storage tank, an ethylene oxide storage tank, and an ice machine system. The water-bath vaporizer has a liquid nitrogen inlet end, a nitrogen outlet end, a coolant inlet end, and a coolant outlet end. The water-bath vaporizer is equipped with a temperature sensor for detecting the temperature of the coolant inside it. The outlet end of the liquid nitrogen storage tank is connected to the liquid nitrogen inlet end of the water-bath vaporizer through a first liquid nitrogen branch, and the outlet end of the liquid nitrogen storage tank is connected to the inlet end of the air-bath vaporizer through a second liquid nitrogen branch. The outlet end of the air-bath vaporizer is connected to a nitrogen-using device through a nitrogen end delivery pipe; the nitrogen outlet end of the water-bath vaporizer is connected to the inlet end of the air-bath vaporizer through a nitrogen intermediate delivery pipe; the outer shell of the ethylene oxide storage tank is provided with a heat exchange jacket. The inlet end of the ice machine system is connected to the outlet end of the coolant storage tank through a first coolant delivery pipeline, and the first coolant delivery pipeline is equipped with a coolant delivery pump. The outlet end of the ice machine system is connected to the inlet end of the heat exchange jacket through a second coolant delivery pipeline, and the outlet end of the heat exchange jacket is connected to the coolant inlet end of the water-bath vaporizer through a third coolant delivery pipeline. The outlet end of the heat exchange jacket is connected to the inlet end of the coolant storage tank through a fourth coolant delivery pipeline. The coolant outlet end of the water-bath vaporizer is connected to the inlet end of the coolant storage tank through a fifth coolant delivery pipeline. A liquid nitrogen main road cut-off valve is provided on the first liquid nitrogen branch, a liquid nitrogen bypass valve is provided on the second liquid nitrogen branch, a jacket outlet coolant main valve is provided on the third coolant delivery pipeline, a jacket outlet coolant bypass valve is provided on the fourth coolant delivery pipeline, and a water-bath vaporizer coolant discharge valve is provided on the fifth coolant delivery pipeline.

[0005] Further preferably: on the corresponding section of the first coolant delivery pipeline between the inlet end of the coolant delivery pump and the outlet end of the coolant storage tank, a coolant delivery pump inlet valve and a coolant storage tank discharge valve are provided.

[0006] Further preferably: on the corresponding section of the first coolant delivery pipeline between the outlet end of the coolant delivery pump and the inlet end of the ice machine system, a pressure gauge, a coolant delivery pump outlet valve, and a coolant check valve are provided.

[0007] Further preferably: the outlet end of the liquid nitrogen storage tank is connected to the inlet ends of the first liquid nitrogen branch and the second liquid nitrogen branch through a liquid nitrogen main pipe, and a liquid nitrogen discharge valve is provided on the liquid nitrogen main pipe.

[0008] Further preferably: a nitrogen flowmeter is installed on the nitrogen end delivery pipe between the outlet end of the air-bath vaporizer and the nitrogen-using device.

[0009] Further preferably, a main nitrogen check valve is provided on the intermediate nitrogen delivery pipe between the nitrogen outlet end of the water bath vaporizer and the air bath vaporizer; a bypass nitrogen check valve is provided on the second liquid nitrogen branch.

[0010] Further preferably, it includes a control system. The main liquid nitrogen cut-off valve, the liquid nitrogen bypass valve, the main coolant valve at the jacket outlet, the bypass coolant valve at the jacket outlet, and the coolant discharge valve of the water bath vaporizer are all electrically controlled valves. The main liquid nitrogen cut-off valve, the liquid nitrogen bypass valve, the main coolant valve at the jacket outlet, the bypass coolant valve at the jacket outlet, the coolant discharge valve of the water bath vaporizer, the ice machine system, and the temperature sensor are all electrically connected to the control system.

[0011] The process control mode of the present utility model is as follows: in the normal operation mode, the bypass coolant valve at the jacket outlet, the liquid nitrogen bypass valve, and the ice machine system are all in the closed state, while the main liquid nitrogen cut-off valve, the main coolant valve at the jacket outlet, the coolant discharge valve of the water bath vaporizer, and the coolant transfer pump are all in the open state. The liquid nitrogen in the liquid nitrogen storage tank sequentially passes through the water bath vaporizer and the air bath vaporizer for heat exchange, and then is connected to the nitrogen-using equipment. If the liquid nitrogen is not completely vaporized after the heat exchange between the coolant in the water bath vaporizer and the liquid nitrogen, the subsequent series-connected air bath vaporizer can completely vaporize the liquid nitrogen to meet the production use. The coolant in the water bath vaporizer can fully absorb the cold of the liquid nitrogen and form a closed-loop pipeline with the heat exchange jacket of the ethylene oxide storage tank and the coolant storage tank to meet the low-temperature storage requirements of the ethylene oxide storage tank. When a situation such as abnormal coolant temperature (i.e., low temperature, prone to freezing failure) occurs in the water bath vaporizer, the bypass process can be used, that is, short-circuit the water bath vaporizer (open the bypass coolant valve at the jacket outlet and the liquid nitrogen bypass valve, close the main liquid nitrogen cut-off valve, the main coolant valve at the jacket outlet, and the coolant discharge valve of the water bath vaporizer), and at the same time start the ice machine system. The ethylene oxide storage tank directly uses the ice machine system for refrigeration, and the liquid nitrogen is vaporized through the air bath vaporizer.

[0012] The beneficial effects of the present utility model are as follows: under normal circumstances, the liquid nitrogen in the liquid nitrogen storage tank sequentially passes through the water bath vaporizer and the air bath vaporizer for heat exchange, and then is connected to the nitrogen-using equipment, which can improve the equipment utilization efficiency. When a fault such as ice blockage occurs in the water bath vaporizer, the bypass process can be used, and the liquid nitrogen is directly vaporized through the air bath vaporizer, and the ethylene oxide storage tank directly uses the ice machine system for refrigeration, thereby better ensuring the continuous and normal operation of the overall production system. Description of the Drawings

[0013] Figure 1 is the overall structural schematic diagram of the present utility model.

[0014] Component markings in the figure: 1 - Liquid nitrogen storage tank; 2 - Liquid nitrogen discharge valve; 3 - Main liquid nitrogen pipe; 4 - Main liquid nitrogen line cut-off valve; 5 - Water bath vaporizer; 6 - Temperature sensor; 7 - Check valve for the main nitrogen line; 8 - Air bath vaporizer; 9 - Nitrogen flow meter; 10 - Nitrogen using equipment; 11 - Fifth coolant transfer pipeline; 12 - Water bath vaporizer coolant discharge valve; 13 - Coolant storage tank; 14 - Coolant storage tank discharge valve; 15 - Coolant transfer pump inlet valve; 16 - Coolant transfer pump; 17 - Pressure gauge; 18 - Coolant transfer pump outlet valve; 19 - Coolant check valve; 20 - Ice machine system; 21 - Ethylene oxide storage tank; 22 - Main valve for coolant at the jacket outlet; 23 - Bypass valve for coolant at the jacket outlet; 24 - Fourth coolant transfer pipeline; 25 - Liquid nitrogen bypass valve; 26 - Second liquid nitrogen branch; 27 - Check valve for the liquid nitrogen bypass. Detailed implementation mode

[0015] The present utility model will be further described below in conjunction with the accompanying drawings and embodiments.

[0016] As Figure 1 shown, the present utility model includes a liquid nitrogen storage tank 1, a water bath vaporizer 5, an air bath vaporizer 8, a coolant storage tank 13, an ethylene oxide storage tank 21, and an ice machine system 20. The water bath vaporizer 5 has a liquid nitrogen inlet end, a nitrogen outlet end, a coolant inlet end, and a coolant outlet end. The water bath vaporizer 5 is equipped with a temperature sensor 6 for detecting the temperature of the coolant inside it. The outlet end of the liquid nitrogen storage tank 1 is connected to the liquid nitrogen inlet end of the water bath vaporizer 5 through a first liquid nitrogen branch. The outlet end of the liquid nitrogen storage tank 1 is connected to the inlet end of the air bath vaporizer 8 through a second liquid nitrogen branch 26. The outlet end of the air bath vaporizer 8 is connected to the nitrogen using equipment 10 through a nitrogen end transfer pipe; the nitrogen outlet end of the water bath vaporizer 5 is connected to the inlet end of the air bath vaporizer 8 through a nitrogen intermediate transfer pipe; the outer shell of the ethylene oxide storage tank 21 is provided with a heat exchange jacket. The inlet end of the ice machine system 20 is connected to the outlet end of the coolant storage tank 13 through a first coolant transfer pipeline. The first coolant transfer pipeline is equipped with a coolant transfer pump 16. The outlet end of the ice machine system 20 is connected to the inlet end of the heat exchange jacket through a second coolant transfer pipeline. The outlet end of the heat exchange jacket is connected to the coolant inlet end of the water bath vaporizer 5 through a third coolant transfer pipeline. The outlet end of the heat exchange jacket is connected to the inlet end of the coolant storage tank 13 through a fourth coolant transfer pipeline 24. The coolant outlet end of the water bath vaporizer 5 is connected to the inlet end of the coolant storage tank 13 through a fifth coolant transfer pipeline 11. A main liquid nitrogen line cut-off valve 4 is provided on the first liquid nitrogen branch. A liquid nitrogen bypass valve 25 is provided on the second liquid nitrogen branch 26. A main valve for coolant at the jacket outlet 22 is provided on the third coolant transfer pipeline. A bypass valve for coolant at the jacket outlet 23 is provided on the fourth coolant transfer pipeline 24. A water bath vaporizer coolant discharge valve 12 is provided on the fifth coolant transfer pipeline 11.

[0017] The secondary refrigerant used therein may adopt various conventional heat exchange process media with relatively low freezing point temperatures. The present utility model preferably adopts a 25% ethylene glycol aqueous solution with a freezing point less than -10°C, which is less likely to freeze compared with conventional chilled water. The water-bath vaporizer 5, the air-bath vaporizer 8, the ethylene oxide storage tank 21, and the ice machine system 20 are all conventional complete sets of equipment in the prior art. The nitrogen using equipment 10 can be understood in a broad sense, and can be various equipment that requires the use of nitrogen, or a nitrogen storage tank.

[0018] In the normal operation mode, the secondary refrigerant bypass valve 23 at the jacket outlet, the liquid nitrogen bypass valve 25, and the ice machine system 20 are all in the closed state, and the liquid nitrogen main road cut-off valve 4, the secondary refrigerant main valve 22 at the jacket outlet, the secondary refrigerant discharge valve 12 of the water-bath vaporizer, and the secondary refrigerant delivery pump 16 are all in the open state. The liquid nitrogen in the liquid nitrogen storage tank 1 sequentially passes through the water-bath vaporizer 5 and the air-bath vaporizer 8 for heat exchange, and then is connected to the nitrogen using equipment 10. If the liquid nitrogen is not completely vaporized after the heat exchange between the secondary refrigerant and the liquid nitrogen in the water-bath vaporizer 5, the series-connected air-bath vaporizer 8 can completely vaporize the liquid nitrogen to meet the production use. The secondary refrigerant in the water-bath vaporizer 5 can fully absorb the cold quantity of the liquid nitrogen, and form a closed-loop pipeline with the heat exchange jacket of the ethylene oxide storage tank 21 and the secondary refrigerant storage tank 21 to meet the low-temperature storage requirements of the ethylene oxide storage tank 21. When the temperature of the secondary refrigerant in the water-bath vaporizer 5 is abnormally low (i.e., the temperature is relatively low and it is easy to have a freezing failure), the bypass process flow can be used, that is, short-circuit the water-bath vaporizer 5 (open the secondary refrigerant bypass valve 23 at the jacket outlet and the liquid nitrogen bypass valve 25, and close the liquid nitrogen main road cut-off valve 4, the secondary refrigerant main valve 22 at the jacket outlet, and the secondary refrigerant discharge valve 12 of the water-bath vaporizer), and at the same time start the ice machine system 20. The ethylene oxide storage tank 21 directly uses the ice machine system 20 for refrigeration, and the liquid nitrogen is directly vaporized through the air-bath vaporizer 8.

[0019] To more conveniently control the delivery control of the secondary refrigerant and the process control, a secondary refrigerant delivery pump inlet valve 15 and a secondary refrigerant storage tank discharge valve 14 are provided on the corresponding section between the inlet end of the secondary refrigerant delivery pump 16 and the outlet end of the secondary refrigerant storage tank 13 on the first secondary refrigerant delivery pipeline; a pressure gauge 17, a secondary refrigerant delivery pump outlet valve 18, and a secondary refrigerant check valve 19 are provided on the corresponding section between the outlet end of the secondary refrigerant delivery pump 16 and the inlet end of the ice machine system 20 on the first secondary refrigerant delivery pipeline. The simultaneous setting of the secondary refrigerant delivery pump inlet valve 15 and the secondary refrigerant delivery pump outlet valve 18 can also facilitate the maintenance of the secondary refrigerant delivery pump 16.

[0020] It can be understood that for the case where the starting connection points of the conveying pipelines in the system are the same or the ending connection points are the same, a common pipeline can be set according to the actual situation. For example, the upstream end of the fourth refrigerant conveying pipeline 24 can also be directly connected to the third refrigerant conveying pipeline, and the connection point is located upstream of the main valve 22 of the refrigerant at the jacket outlet (the side closer to the outlet end of the heat exchange jacket); the downstream end of the fourth refrigerant conveying pipeline 24 can also be directly connected to the fifth refrigerant conveying pipeline 11, and the connection point is located downstream of the outlet valve 12 of the refrigerant of the water-bath vaporizer (the side closer to the inlet end of the refrigerant storage tank 13). For the convenience of pipeline connection, the first liquid nitrogen branch and the second liquid nitrogen branch 26 can also share a section of the main liquid nitrogen pipeline 3, that is, it is equivalent to the outlet end of the liquid nitrogen storage tank 1 being connected to the inlet end of the first liquid nitrogen branch and the inlet end of the second liquid nitrogen branch 26 through the main liquid nitrogen pipeline 3 at the same time. Preferably, a liquid nitrogen outlet valve 2 is provided on the main liquid nitrogen pipeline 3.

[0021] To facilitate the control of the nitrogen use process parameters at the end of the system, preferably, a nitrogen flowmeter 9 is installed on the nitrogen end conveying pipeline between the outlet end of the air-bath vaporizer 8 and the nitrogen use equipment 10.

[0022] To more conveniently control the flow direction of liquid nitrogen and ensure its smooth access to the air-bath vaporizer 8, a main nitrogen path check valve 7 is provided on the nitrogen intermediate conveying pipeline between the nitrogen outlet end of the water-bath vaporizer 5 and the air-bath vaporizer 8; a liquid nitrogen bypass check valve 27 is provided on the second liquid nitrogen branch 26. The functions of the main nitrogen path check valve 7 and the liquid nitrogen bypass check valve 27 are: to prevent the reverse flow of liquid nitrogen when switching between the main liquid nitrogen path and the bypass.

[0023] The bypass process flow of the present invention can be switched manually or automatically by the control system. To improve the automation level and reduce the labor intensity of workers, preferably, the automatic switching of the control system can be adopted. Specifically, the main liquid nitrogen path cut-off valve 4, the liquid nitrogen bypass valve 25, the main valve 22 of the refrigerant at the jacket outlet, the bypass valve 23 of the refrigerant at the jacket outlet, and the outlet valve 12 of the refrigerant of the water-bath vaporizer are all electrically controlled valves. The main liquid nitrogen path cut-off valve 4, the liquid nitrogen bypass valve 25, the main valve 22 of the refrigerant at the jacket outlet, the bypass valve 23 of the refrigerant at the jacket outlet, the outlet valve 12 of the refrigerant of the water-bath vaporizer, the ice machine system 20, and the temperature sensor 6 are all electrically connected to the control system, thereby realizing linkage control. It can be understood that controlling the action of the actuators (each control valve in the present invention) through temperature thresholds belongs to the conventional control process, and the present invention does not involve the improvement of computer programs.

[0024] In the preferred embodiment of the present invention, the operation control can be carried out in the following manner:

[0025] Before operation, close the bypass valve 23 of the refrigerant at the jacket outlet and the liquid nitrogen bypass valve 25, and turn off the ice machine system 20.

[0026] Open the outlet valve 14 of the secondary refrigerant storage tank, the inlet valve 15 of the secondary refrigerant transfer pump, and the main valve 22 of the secondary refrigerant at the jacket outlet. Start the secondary refrigerant transfer pump 16. After the pressure gauge 17 detects normal pressure, open the outlet valve 18 of the secondary refrigerant transfer pump, and the secondary refrigerant (25% ethylene glycol solution) forms a closed loop.

[0027] Then, open the liquid nitrogen outlet valve 2 and the main liquid nitrogen line cut-off valve 4 in sequence. The liquid nitrogen exchanges heat through the water-bath vaporizer 5 and the air-bath vaporizer 8.

[0028] Set interlock control: When the temperature value detected by the temperature sensor 6 is close to the freezing point temperature of the secondary refrigerant (the specific threshold range of temperature control can be determined according to the actual process conditions, and the present utility model does not claim to protect the specific control program), automatically open the bypass valve 23 of the secondary refrigerant at the jacket outlet and the bypass valve 25 of the liquid nitrogen. Then close the main valve 22 of the secondary refrigerant at the jacket outlet, the outlet valve 12 of the secondary refrigerant of the water-bath vaporizer, and the main liquid nitrogen line cut-off valve 4. At the same time, automatically start the ice machine system 20. After short-circuiting the water-bath vaporizer 5 in this way, it can effectively prevent the secondary refrigerant in the water-bath vaporizer 5 from freezing and blocking the equipment, thus affecting the normal circulation operation of the secondary refrigerant.

[0029] After the ice blockage problem is solved, the original pipeline operation can be restored.

Claims

1. Liquid nitrogen cold energy recovery system, comprising a liquid nitrogen storage tank (1), a water bath vaporizer (5), an air bath vaporizer (8) and a secondary coolant storage tank (13). The water bath vaporizer (5) has a liquid nitrogen inlet end, a nitrogen outlet end, a secondary coolant inlet end and a secondary coolant outlet end, and is equipped with a temperature sensor (6) for detecting the temperature of the secondary coolant inside it; the outlet end of the liquid nitrogen storage tank (1) is connected to the liquid nitrogen inlet end of the water bath vaporizer (5) through a first liquid nitrogen branch, the outlet end of the liquid nitrogen storage tank (1) is connected to the inlet end of the air bath vaporizer (8) through a second liquid nitrogen branch (26), and the outlet end of the air bath vaporizer (8) is connected to a nitrogen using device (10) through a nitrogen end delivery pipe; a liquid nitrogen main road cut-off valve (4) is provided on the first liquid nitrogen branch, a liquid nitrogen bypass valve (25) is provided on the second liquid nitrogen branch (26), the secondary coolant outlet end of the water bath vaporizer (5) is connected to the inlet end of the secondary coolant storage tank (13) through a fifth secondary coolant delivery pipeline (11), and a water bath vaporizer secondary coolant discharge valve (12) is provided on the fifth secondary coolant delivery pipeline (11), characterized in that: It includes an ethylene oxide storage tank (21) and an ice machine system (20); the nitrogen outlet end of the water bath vaporizer (5) is connected to the inlet end of the air bath vaporizer (8) through a nitrogen intermediate delivery pipe; the outer shell of the ethylene oxide storage tank (21) is equipped with a heat exchange jacket, the inlet end of the ice machine system (20) is connected to the outlet end of the coolant storage tank (13) through a first coolant delivery pipeline, the first coolant delivery pipeline is equipped with a coolant delivery pump (16), the outlet end of the ice machine system (20) is connected to the inlet end of the heat exchange jacket through a second coolant delivery pipeline, the outlet end of the heat exchange jacket is connected to the coolant inlet end of the water bath vaporizer (5) through a third coolant delivery pipeline, the outlet end of the heat exchange jacket is connected to the inlet end of the coolant storage tank (13) through a fourth coolant delivery pipeline (24), a main valve for the coolant at the jacket outlet (22) is provided on the third coolant delivery pipeline, and a bypass valve for the coolant at the jacket outlet (23) is provided on the fourth coolant delivery pipeline (24).

2. The liquid nitrogen cold energy recovery system according to claim 1, wherein: On the corresponding section of the first coolant delivery pipeline between the inlet end of the coolant delivery pump (16) and the outlet end of the coolant storage tank (13), a coolant delivery pump inlet valve (15) and a coolant storage tank discharge valve (14) are provided.

3. The liquid nitrogen cold energy recovery system according to claim 1, characterized in that: On the corresponding section of the first coolant delivery pipeline between the outlet end of the coolant delivery pump (16) and the inlet end of the ice machine system (20), a pressure gauge (17), a coolant delivery pump outlet valve (18) and a coolant check valve (19) are provided.

4. The liquid nitrogen cold energy recovery system according to claim 1, wherein: The outlet end of the liquid nitrogen storage tank (1) is connected to the inlet end of the first liquid nitrogen branch and the inlet end of the second liquid nitrogen branch (26) through a liquid nitrogen main pipe (3), and a liquid nitrogen discharge valve (2) is provided on the liquid nitrogen main pipe (3).

5. The liquid nitrogen cold energy recovery system according to claim 1, wherein: A nitrogen flowmeter (9) is installed on the nitrogen end delivery pipe between the outlet end of the air bath vaporizer (8) and the nitrogen using equipment (10).

6. The liquid nitrogen cold energy recovery system according to claim 1, wherein: A nitrogen main road check valve (7) is provided on the nitrogen intermediate delivery pipe between the nitrogen outlet end of the water bath vaporizer (5) and the air bath vaporizer (8); a liquid nitrogen bypass check valve (27) is provided on the second liquid nitrogen branch (26).

7. The liquid nitrogen cold energy recovery system according to any one of claims 1 to 6, characterized in that: It includes a control system. The liquid nitrogen main road cut-off valve (4), the liquid nitrogen bypass valve (25), the main valve for the coolant at the jacket outlet (22), the bypass valve for the coolant at the jacket outlet (23) and the coolant discharge valve for the water bath vaporizer (12) are all electrically controlled valves. The liquid nitrogen main road cut-off valve (4), the liquid nitrogen bypass valve (25), the main valve for the coolant at the jacket outlet (22), the bypass valve for the coolant at the jacket outlet (23), the coolant discharge valve for the water bath vaporizer (12), the ice machine system (20) and the temperature sensor (6) are all electrically connected to the control system.

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