A liquid nitrogen cold energy recovery and vaporization system

Abstract

This utility model discloses a liquid nitrogen cold energy recovery and vaporization system, which includes a liquid nitrogen storage tank, a vaporizer, and a buffer tank. The liquid nitrogen cold energy recovery and vaporization system also includes a refrigerant tank, a three-way reversing valve, and a controller. The refrigerant tank is connected to the liquid nitrogen storage tank and the vaporizer, and is used to recover the cold energy of liquid nitrogen and to transport the heated liquid nitrogen to the vaporizer for vaporization. The three-way reversing valve is used to switch the flow of liquid nitrogen from the liquid nitrogen storage tank between the vaporizer and the refrigerant tank. The controller is used to realize the automatic switching of the three-way reversing valve.

Description

Technical Field

[0001] This utility model relates to liquid nitrogen systems, and more specifically, to a system that combines liquid nitrogen cold energy recovery and vaporization. Background Technology

[0002] In existing industrial production cases, devices or systems used to supply nitrogen typically directly input stored liquid nitrogen into a vaporizer for vaporization. A significant amount of cold energy released during vaporization is directly dissipated into the atmosphere through the vaporizer surface, meaning this energy is often not effectively utilized. In many cases, the temperature of the vaporized nitrogen is still lower than the required temperature for downstream equipment, necessitating additional electric heating devices to reheat the nitrogen to the operating temperature before use. This process wastes both the cold energy from liquid nitrogen vaporization and the electrical energy used to heat the nitrogen, resulting in a double waste of energy and extremely poor economic efficiency. Furthermore, most current factory refrigerant supply systems use high-power refrigeration compressors to lower the refrigerant temperature. This refrigeration method is extremely energy-intensive, with the compressor accounting for 60% to 80% of the total energy consumption of the refrigerant supply system.

[0003] To fully utilize the cold energy generated during the liquid nitrogen vaporization process and reduce the refrigeration energy consumption of the plant's refrigerant supply system, various systems capable of recovering liquid nitrogen cold energy have been developed in the prior art. For example, prior art CN118499682A discloses a liquid nitrogen cold energy recovery system, which includes a liquid nitrogen tank, a cold energy recovery heat exchanger, and a vaporizer. The cold energy recovered by the cold energy recovery heat exchanger is absorbed by circulating water, thereby cooling the water stored in the circulating water tank. Part of the liquid nitrogen after heat exchange flows into the vaporizer from the second outlet pipe for vaporization. Prior art CN222027200U discloses a nitrogen and cold energy recovery system after liquid nitrogen use, which includes a heat exchanger with a chilled water inlet for supplying chilled water and a nitrogen inlet for supplying low-temperature nitrogen after liquid nitrogen vaporization in the reactor. The chilled water outlet of the heat exchanger is connected to a chilled water tank, and the nitrogen outlet of the heat exchanger is connected to a nitrogen reheater for restoring nitrogen to room temperature. The nitrogen reheater is connected to a recovery assembly. Although these existing technologies disclose the recovery of liquid nitrogen cold energy, their liquid nitrogen processes are simple, and in existing technologies, the recovered nitrogen cold energy is generally used to cool circulating water. Excessive cold energy recovery can easily cause the cooling temperature of the circulating water to be too low (below 0°C) and freeze, resulting in the circulating water not being able to flow, increasing the failure rate of the recovery system, and failing to provide cooling water in a timely manner.

[0004] Therefore, there is an urgent need for a refrigerant supply system that can both recover liquid nitrogen cold energy on demand for use in factories and provide a stable supply of nitrogen to meet the factory's needs for cooling equipment and nitrogen. Utility Model Content

[0005] This invention provides a liquid nitrogen cold energy recovery and vaporization system. This system can both recover liquid nitrogen cold energy on demand for use in a factory's refrigerant supply system and provide stable nitrogen gas to meet the factory's needs for cooling equipment and nitrogen. To achieve the objectives of this invention, the following solutions are adopted:

[0006] A liquid nitrogen cold energy recovery and vaporization system includes a liquid nitrogen storage tank, a vaporizer, and a buffer tank. The system further includes a refrigerant tank, a three-way reversing valve, and a controller. The refrigerant tank is connected to the liquid nitrogen storage tank and the vaporizer, and is used to recover the cold energy of the liquid nitrogen and to transport the heated liquid nitrogen to the vaporizer for vaporization. The three-way reversing valve switches the flow of liquid nitrogen from the liquid nitrogen storage tank between the vaporizer and the refrigerant tank. The controller enables automatic switching of the three-way reversing valve.

[0007] In another preferred embodiment, the refrigerant tank includes an inner cavity and a spiral coil disposed in the inner cavity, the inner cavity also serving to contain refrigerant, and the spiral coil serving to allow liquid nitrogen from the liquid nitrogen storage tank to flow therein and to transfer the cooling energy of the liquid nitrogen to the refrigerant.

[0008] In another preferred embodiment, the refrigerant tank further includes a thermometer and a level gauge. The thermometer is used to detect the temperature of the refrigerant, and the level gauge is used to detect the liquid level of the refrigerant. The thermometer is connected to the controller and sends the detected temperature information to the controller, and the level gauge is connected to the controller and sends the detected liquid level information to the controller.

[0009] In another preferred embodiment, the three-way reversing valve has three ports, namely a first port, a second port, and a third port, wherein the first port is connected to the liquid nitrogen storage tank, the second port is connected to the refrigerant tank, the third port is connected to the vaporizer, and the three-way reversing valve is connected to the controller, which controls the three-way reversing valve to switch between the second port and the third port according to the received temperature information.

[0010] In another preferred embodiment, the first port of the three-way reversing valve is connected to the liquid nitrogen outlet of the liquid nitrogen storage tank via a first pipe, the second port is connected to the liquid nitrogen inlet of the refrigerant tank via a second pipe, and the third port is connected to the liquid nitrogen inlet of the vaporizer via a third pipe. When the first and second ports of the three-way reversing valve are connected, the liquid nitrogen in the liquid nitrogen storage tank flows to the refrigerant tank. When the first and third ports of the three-way reversing valve are connected, the liquid nitrogen in the liquid nitrogen storage tank flows to the vaporizer.

[0011] In another preferred embodiment, the refrigerant tank is connected to the vaporizer via a fourth pipe.

[0012] In another preferred embodiment, the refrigerant tank is connected to the plant's refrigerant supply system via a first refrigerant main return pipe and a second refrigerant main return pipe in a pipe gallery. The first refrigerant main return pipe in a pipe gallery is used to transport the refrigerant from the plant's refrigerant supply system to the refrigerant tank, and the second refrigerant main return pipe in a pipe gallery is used to transport the refrigerant from the refrigerant tank to the plant's refrigerant supply system. A regulating valve is installed on the first refrigerant main return pipe in a pipe gallery to control the flow rate of the refrigerant entering the refrigerant tank. A pump is installed on the second refrigerant main return pipe in a pipe gallery to pump the refrigerant from the refrigerant tank into the plant's refrigerant supply system. The regulating valve is connected to a controller, and the controller controls the opening and closing of the regulating valve based on received liquid level information. The pump is connected to the controller, and the controller controls the opening and closing of the pump based on received liquid level information.

[0013] In another preferred embodiment, the refrigerant tank is connected to the plant refrigerant main return pipe of the plant area refrigerant supply system via the refrigerant main return pipe of the first pipe gallery and the refrigerant main return pipe of the second pipe gallery.

[0014] In another preferred embodiment, the vaporizer is an ambient temperature vaporizer.

[0015] In another preferred embodiment, the ambient air vaporizer includes multiple heat-conducting tubes, each heat-conducting tube having radially distributed fins evenly distributed on its outer wall, with adjacent fins having an included angle.

[0016] In another preferred embodiment, the included angle between adjacent fins on the two rows of 12 heat-conducting tubes on the liquid nitrogen inlet side of the ambient temperature vaporizer is 45 degrees, and the included angle between adjacent fins on the remaining 5 rows of 30 tubes is 30 degrees.

[0017] In another preferred embodiment, the buffer tank is equipped with a pressure transmitter and a safety valve, the pressure transmitter displaying the real-time pressure of nitrogen gas inside the buffer tank.

[0018] In another preferred embodiment, the vaporizer and the buffer tank are connected via a fifth pipe, which is equipped with a pressure reducing valve and a safety valve. The pressure reducing valve is used to reduce the pressure of high-pressure nitrogen from the vaporizer to low-pressure nitrogen.

[0019] Compared with existing technologies, the liquid nitrogen cold energy recovery and vaporization system of this invention has the following advantages:

[0020] The system of this invention achieves automatic on-demand recovery of liquid nitrogen cooling energy by setting up a refrigerant tank, a three-way reversing valve and a controller, and can provide a stable supply of nitrogen gas.

[0021] The refrigerant tank of this invention allows liquid nitrogen to exchange energy with the refrigerant, and the resulting low-temperature refrigerant is delivered to the plant's refrigerant supply system to provide cooling energy for the devices that need to be cooled, thus greatly saving the refrigeration energy consumption of the plant's refrigerant supply system's refrigeration compressor.

[0022] The controller of this invention switches the liquid nitrogen flow path as needed based on the temperature and level signals of the refrigerant in the refrigerant tank, thereby achieving on-demand control of cold energy recovery.

[0023] The system of this invention suppresses gas supply pressure fluctuations by setting up a buffer tank, thus ensuring the stability of nitrogen supply. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or components are generally identified by similar reference numerals. In the drawings, the elements or components are not necessarily drawn to scale.

[0025] Figure 1 A schematic diagram of a liquid nitrogen cold energy recovery and vaporization system according to a specific embodiment of the present invention is shown.

[0026] Figure 2 The connection to the plant's refrigerant supply system is shown. Figure 1 The liquid nitrogen cold energy recovery and vaporization system.

[0027] Figure 3A Showing Figure 1 Front view of vaporizer 4.

[0028] Figure 3B Showing Figure 1 Top view of vaporizer 4.

[0029] Figure 1 and 2 In the diagram, 1—liquid nitrogen storage tank, 11—first pipeline, 2—three-way directional valve, 21—first port of three-way directional valve, 22—second port of three-way directional valve, 23—third port of three-way directional valve, 221—second pipeline, 231—third pipeline, 3—refrigerant tank, 31—coil, 311—fourth pipeline, 32—…

[0030] —Inner cavity, 33—Refrigerant main return pipe of the first pipe gallery, 34—Refrigerant main return pipe of the second pipe gallery, 35—Regulating valve, 36—Pump, 37—Level gauge, 38—Thermometer, 4—Vaporizer, 41—Heat pipe, 411—Radial fins, 42—Fifth pipe, 43—Pressure reducing valve, 44—Safety valve, 45—First pressure gauge, 46—Second pressure gauge, 5—Buffer tank, 51—Safety valve, 52—Pressure transmitter, 6—Controller, 100—Plant refrigerant supply system, 101—Refrigeration compressor, 102—Refrigerant tank, 103—Refrigerant main return pipe of the plant, 104—Refrigerant main inlet pipe of the plant, 200—Equipment requiring cooling. Detailed Implementation

[0031] The liquid nitrogen cold energy recovery and vaporization system of this invention can automatically recover the cold energy generated during the liquid nitrogen vaporization process as needed, and can also provide a stable supply of nitrogen.

[0032] In the description of this utility model, terms such as "inlet" and "outlet" are understood in accordance with the conventional understanding in the art. This is provided to facilitate implementation by those skilled in the art.

[0033] In the description of this utility model, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0034] In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0035] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] In the description of this utility model, "pressure reducing valve", "pressure transmitter" and "safety valve" are all conventional devices used in this field.

[0037] In this invention, the refrigerant is preferably a medium with a low freezing point, such as a 60% ethylene glycol solution, which effectively prevents the refrigerant from freezing and becoming stagnant. The refrigerant flows between the plant's refrigerant supply system and the devices requiring cooling, thereby lowering the temperature of the devices.

[0038] To facilitate understanding of this utility model, the following description will be provided in more comprehensive and detailed manner with reference to the accompanying drawings and preferred embodiments. However, the scope of protection of this utility model is not limited to the following specific embodiments.

[0039] See Figure 1 The figure shows a schematic diagram of the structure of a liquid nitrogen cold energy recovery and vaporization system according to a specific embodiment of the present invention. The liquid nitrogen cold energy recovery and vaporization system of this embodiment includes: a liquid nitrogen storage tank 1, a three-way reversing valve 2, a refrigerant tank 3, a vaporizer 4, a nitrogen buffer tank 5, and a controller 6.

[0040] Figure 2 The connection to the plant's refrigerant supply system is shown. Figure 1 The liquid nitrogen cold energy recovery and vaporization system, and the plant refrigerant supply system 100 are conventional refrigerant supply systems in the field, commercially available, including a refrigeration compressor 101, a refrigerant tank 102, a plant refrigerant main return pipe 103, and a plant refrigerant main inlet pipe 104. The refrigeration compressor 101 is connected to the refrigerant tank 102, the former increasing the cold energy of the latter, thus cooling the refrigerant in the refrigerant tank. The refrigerant tank 102 is used to store refrigerant and is connected to the device 200 to be cooled through the plant refrigerant main return pipe 103 and the plant refrigerant main inlet pipe 104. The refrigerant flowing in the plant refrigerant main return pipe has increased in temperature after flowing through the device 200 to be cooled, while the refrigerant flowing in the plant refrigerant main inlet pipe has a lower temperature and flows out of the refrigerant tank 102.

[0041] exist Figure 1 In a specific embodiment, the controller 6 receives signals collected by the sensors and controls the operation of the drive unit based on the received signals. The controller 6 can execute pre-set logic instructions, determine and execute corresponding control operations based on the sensor signals, such as adjusting the opening or switching of the regulating valve, controlling the pump speed or switching of the pump, and controlling the three-way reversing valve to switch between different ports. The controller can be part of the control system of the liquid nitrogen cold energy recovery and vaporization system, or it can be an independent controller.

[0042] exist Figure 1 In a specific embodiment, the liquid nitrogen storage tank 1 can be a conventional liquid nitrogen storage device in the art, such as a vacuum-insulated container (e.g., with a volume of 50m³). 3 The liquid nitrogen outlet at its bottom is connected to the three-way reversing valve 2 via the first pipe 11 (e.g., DN40 stainless steel pipe). The design pressure is 1.2 MPa.

[0043] exist Figure 1In a specific embodiment, the three-way reversing valve 2 has three ports: a first port 21, a second port 22, and a third port 23. The first port 21 is connected to the liquid nitrogen outlet of the storage tank 1 via a first pipe 11 (e.g., a DN40 stainless steel pipe). The second port 22 is connected to the liquid nitrogen inlet of the refrigerant tank 3 via a second pipe 221 (e.g., a DN40 stainless steel pipe), introducing liquid nitrogen from the liquid nitrogen storage tank 1 into the refrigerant tank 3. The third port 23 is connected to the liquid nitrogen inlet of the vaporizer 4 via a third pipe 231 (e.g., a DN40 stainless steel pipe), introducing liquid nitrogen from the storage tank 1 into the vaporizer 4. The three-way reversing valve 2 is also connected to a controller 6 and is controlled by the controller 6 to automatically switch between the second port 22 and the third port 23.

[0044] In this embodiment, the refrigerant tank 3 is a container with an internal spiral coil 31 (e.g., a volume of 2.5m³). 3 The refrigerant tank 3 is a 316L stainless steel container, with a spiral coil 31 housed within its inner cavity 32. Liquid nitrogen flows inside the spiral coil 31, which is connected to the liquid nitrogen storage tank 1 via a first pipe 11 and a second pipe 221, and to the vaporizer 4 via a fourth pipe 311. Thus, the liquid nitrogen from the storage tank 1, after having some of its cooling energy recovered in the refrigerant tank 3, enters the vaporizer 4 for vaporization. The inner cavity of the refrigerant tank 3 also contains refrigerant (e.g., a 60% ethylene glycol solution), which contacts and absorbs the cooling energy of the liquid nitrogen within the spiral coil 31. The refrigerant tank 3 has a refrigerant inlet at the top and a refrigerant outlet at the bottom. The refrigerant inlet and outlet are connected to the plant's refrigerant supply system 100 (see [reference needed]) via a first pipe gallery refrigerant main return pipe 33 and a second pipe gallery refrigerant main return pipe 34, respectively. Figure 2 The refrigerant main return pipe 103 of the plant area is connected. A regulating valve 35 (e.g., a DN50 pneumatic regulating valve) is installed on the refrigerant main return pipe 33 of the first pipe rack to regulate the flow rate of refrigerant entering the refrigerant tank 3 from the plant area's refrigerant supply system. The regulating valve 35 is connected to a controller 6, which controls its opening or switching. A pump 36 is installed on the refrigerant main return pipe 34 of the second pipe rack to pump the refrigerant from the refrigerant tank 3 into the plant area's refrigerant supply system. The pump 36 is connected to a controller 6, which controls its pump speed or switching.

[0045] The refrigerant tank 3 is also equipped with a level gauge 37 (e.g., a float level gauge with a range of 0-3m) for detecting the refrigerant level inside. The level gauge 37 is connected to the controller 6 and sends the detected refrigerant level information to the controller 6. When the level gauge 37 detects that the refrigerant level in the refrigerant tank 3 is lower than the first low level (e.g., 0.5m), the controller 6, based on the received level information, increases the opening of the regulating valve 35, thereby increasing the flow rate of the refrigerant entering the refrigerant tank 3. When the level gauge 37 detects that the refrigerant level in the refrigerant tank 3 is lower than the second low level (e.g., 0.3m), the controller 6, based on the received level information, shuts off the delivery pump 36 to prevent it from running dry (i.e., no refrigerant is pumped into the second pipe). (Refrigerant main return pipe 34); When the level gauge 37 detects that the refrigerant level in the refrigerant tank 3 has risen to the first high level (e.g., 2m), the controller 6 adjusts the opening of the regulating valve 34 according to the received level information, so that the flow rate of the refrigerant entering the refrigerant tank 3 is reduced; When the level gauge 37 detects that the refrigerant level in the refrigerant tank 3 has risen to the second high level (e.g., 2.5m), the controller 6 closes the regulating valve 35 according to the received level information, so that the refrigerant stops entering the refrigerant tank 3.

[0046] The refrigerant tank 3 is also equipped with a thermometer 38 for detecting the temperature of the refrigerant inside the tank. The thermometer 38 is connected to the controller 6 and sends the detected refrigerant temperature information to the controller 6. The controller 6 controls the three-way reversing valve 2 according to the preset cold energy recovery mode trigger temperature (e.g., 10°C) and liquid nitrogen direct flow mode switching temperature (e.g., -5°C). In the "cold energy recovery mode", the first port 21 and the second port 22 of the three-way reversing valve 2 are connected, connecting the liquid nitrogen storage tank 1 and the refrigerant tank 3, so that the liquid nitrogen in the liquid nitrogen storage tank 1 flows into the refrigerant tank 3. In the "liquid nitrogen direct flow mode", the first port 21 and the third port 23 of the three-way reversing valve 2 are connected, connecting the liquid nitrogen storage tank 1 and the vaporizer 4, so that the liquid nitrogen in the liquid nitrogen storage tank 1 flows directly into the vaporizer 4. When thermometer 38 detects that the refrigerant temperature has risen to the cold energy recovery mode trigger temperature, controller 6, based on the received temperature information, controls the three-way reversing valve 2 to close the third port 23 and open the first port 21 and the second port 22, allowing liquid nitrogen from liquid nitrogen storage tank 1 to flow into the spiral coil 31 in refrigerant tank 3 and exchange energy with the refrigerant in refrigerant tank 3. When thermometer 38 detects that the refrigerant temperature has dropped to the liquid nitrogen direct flow mode switching temperature, controller 6, based on the received temperature information, controls the three-way reversing valve 2 to close the second port 22 and open the first port 21 and the third port 23, allowing liquid nitrogen from liquid nitrogen storage tank 1 to flow directly into vaporizer 4, where it vaporizes to form nitrogen gas.

[0047] In this embodiment, the vaporizer 4 can adopt an ambient temperature structure. The ambient temperature structure vaporizer 4 is provided with multiple (e.g., 42) heat conduction tubes 41, and radial fins 411 are evenly distributed on the outer wall of each heat conduction tube. Adjacent fins have an included angle (e.g., the included angle between adjacent fins on the two rows of 12 heat conduction tubes on the liquid nitrogen inlet side is 45°, and the included angle between adjacent fins on the remaining 5 rows of 30 tubes is 30°).

[0048] The vaporizer 4 is connected to the nitrogen buffer tank 6 via a fifth pipe 42 (e.g., a DN40 stainless steel pipe). A pressure reducing valve 43, a safety valve 44, a first pressure gauge 45, and a second pressure gauge 46 are installed on the fifth pipe 42. The safety valve 44 and the first pressure gauge 45 are located upstream of the pressure reducing valve 43 (according to the direction of nitrogen flow, the first point of flow is upstream, and the last point of flow is downstream), while the second pressure gauge 46 is located downstream of the pressure reducing valve 43. The safety valve 44 has a set pressure (e.g., 1.0 MPa) and a set response time (e.g., <0.1 seconds). The pressure reducing valve 43 reduces the high-pressure nitrogen from the vaporizer 4 (e.g., 0.6–0.8 MPa) to low-pressure nitrogen (e.g., 0.25 MPa).

[0049] In this embodiment, the nitrogen buffer tank 5 is used to store gaseous nitrogen from the vaporizer 4, and it is equipped with a safety valve 51 and a pressure transmitter 52 (e.g., at the top). The safety valve 51 is set with a set pressure (e.g., 0.3 MPa), and suppresses the nitrogen pressure fluctuation amplitude within a certain range (e.g., within ±0.01 MPa) through the volumetric damping effect, thus avoiding nitrogen pressure instability. The pressure transmitter 52 is used to display the nitrogen pressure in the nitrogen buffer tank 6 in real time. The stabilized nitrogen is then delivered to devices requiring nitrogen protection (e.g., reaction vessels or crystallizers) through the sixth pipeline 63.

[0050] This utility model's liquid nitrogen cold energy recovery and vaporization system can reduce the refrigerant temperature of the plant's refrigerant supply system from 10°C to -5°C within 30 minutes. It boasts high cold energy recovery efficiency, significantly reducing the energy consumption of the refrigeration compressor in the plant's refrigerant supply system. Furthermore, the cold energy recovery mode trigger temperature and the liquid nitrogen direct-flow mode switching temperature can be set according to actual needs. For example, when the plant's refrigerant supply system requires a lower refrigerant temperature, a higher cold energy recovery mode trigger temperature and a lower liquid nitrogen direct-flow mode switching temperature can be set; conversely, when the plant's refrigerant supply system does not require a lower refrigerant temperature (e.g., 10°C), a higher liquid nitrogen direct-flow mode switching temperature can be set.

[0051] Taking a pharmaceutical raw material company as an example, during the operation of the liquid nitrogen cold energy recovery and vaporization system, the refrigerant circulation volume in the cold energy recovery mode reaches 6.3m³. 3 / h, the refrigerant temperature is stabilized at -5℃. In liquid nitrogen direct-flow mode, safety valve 44 releases pressure within 0.1 seconds when the inlet pressure exceeds 0.1MPa, and safety valve 51 of the buffer tank intercepts pressure exceeding 0.3MPa, preventing the occurrence of unstable nitrogen supply in the workshop.

[0052] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. A liquid nitrogen cold energy recovery and vaporization system, comprising a liquid nitrogen storage tank, a vaporizer, and a buffer tank, characterized in that, The liquid nitrogen cold energy recovery and vaporization system also includes a refrigerant tank, a three-way reversing valve, and a controller. The refrigerant tank is connected to the liquid nitrogen storage tank and the vaporizer, and is used to recover the cold energy of the liquid nitrogen and to transport the heated liquid nitrogen to the vaporizer for vaporization. The three-way reversing valve is used to switch the flow of liquid nitrogen from the liquid nitrogen storage tank between the vaporizer and the refrigerant tank. The controller is used to enable automatic switching of the three-way directional valve.

2. The liquid nitrogen cold energy recovery and vaporization system according to claim 1, characterized in that, The refrigerant tank includes an inner cavity and a spiral coil disposed in the inner cavity. The inner cavity is also used to contain refrigerant, and the spiral coil is used to allow liquid nitrogen from the liquid nitrogen storage tank to flow therein and to transfer the cooling energy of the liquid nitrogen to the refrigerant.

3. The liquid nitrogen cold energy recovery and vaporization system according to claim 2, characterized in that, The refrigerant tank also includes a thermometer and a level gauge. The thermometer is used to detect the temperature of the refrigerant, and the level gauge is used to detect the liquid level of the refrigerant. The thermometer is connected to the controller and sends the detected temperature information to the controller. The level gauge is connected to the controller and sends the detected level information to the controller.

4. The liquid nitrogen cold energy recovery and vaporization system according to claim 3, characterized in that, The three-way reversing valve has three ports: a first port, a second port, and a third port. The first port is connected to the liquid nitrogen storage tank, the second port is connected to the refrigerant tank, and the third port is connected to the vaporizer. The three-way reversing valve is connected to the controller, and the controller controls the three-way reversing valve to switch between the second port and the third port according to the received temperature information.

5. The liquid nitrogen cold energy recovery and vaporization system according to claim 4, characterized in that, The first port of the three-way reversing valve is connected to the liquid nitrogen outlet of the liquid nitrogen storage tank via a first pipe, the second port is connected to the liquid nitrogen inlet of the refrigerant tank via a second pipe, and the third port is connected to the liquid nitrogen inlet of the vaporizer via a third pipe. When the first and second ports of the three-way reversing valve are connected, the liquid nitrogen in the liquid nitrogen storage tank flows to the refrigerant tank. When the first and third ports of the three-way reversing valve are connected, the liquid nitrogen in the liquid nitrogen storage tank flows to the vaporizer.

6. The liquid nitrogen cold energy recovery and vaporization system according to claim 5, characterized in that, The refrigerant tank and the vaporizer are connected via a fourth pipe.

7. The liquid nitrogen cold energy recovery and vaporization system according to claim 4, characterized in that, The refrigerant tank is connected to the plant's refrigerant supply system via a first pipe gallery refrigerant main return pipe and a second pipe gallery refrigerant main return pipe. The first pipe gallery refrigerant main return pipe is used to transport the refrigerant from the plant's refrigerant supply system to the refrigerant tank, and the second pipe gallery refrigerant main return pipe is used to transport the refrigerant from the refrigerant tank to the plant's refrigerant supply system. A regulating valve is installed on the return pipe of the first pipe gallery refrigerant main to control the flow rate of refrigerant entering the refrigerant tank. A pump is installed on the return pipe of the refrigerant main in the second pipe gallery to pump the refrigerant from the refrigerant tank into the plant's refrigerant supply system. The regulating valve is connected to the controller, which controls the opening and closing of the regulating valve based on the received liquid level information. The pump is connected to the controller, which controls the pump's opening and closing based on the received liquid level information.

8. The liquid nitrogen cold energy recovery and vaporization system according to claim 1 or 2, characterized in that, The vaporizer is an ambient temperature vaporizer.

9. The liquid nitrogen cold energy recovery and vaporization system according to claim 8, characterized in that, The ambient temperature vaporizer includes multiple heat-conducting tubes, each with radially distributed fins on its outer wall, and adjacent fins having an included angle.

10. The liquid nitrogen cold energy recovery and vaporization system according to claim 1 or 2, characterized in that, The buffer tank is equipped with a pressure transmitter and a safety valve. The pressure transmitter displays the real-time pressure of nitrogen gas inside the buffer tank, and / or The vaporizer and the buffer tank are connected by a fifth pipe, which is equipped with a pressure reducing valve and a safety valve. The pressure reducing valve is used to reduce the pressure of high-pressure nitrogen from the vaporizer to low-pressure nitrogen.

Images