Liquid nitrogen vaporization system

Abstract

A liquid nitrogen vaporization system, comprising liquid nitrogen supply units, a vaporization apparatus, a heater, a cushioning tank, and a nitrogen output pressure regulating apparatus which are sequentially connected, and a controller. The controller is separately electrically connected to a supercharging apparatus, the vaporization apparatus, the heater, and the nitrogen output pressure regulating apparatus. In the system, redundancy devices are configured for important individual devices and a controller is additionally provided, and the controller monitors an operation state and a parameter change of each device in real time, and controls each individual device and each pipeline switch valve by means of a set automatic control program, so that the liquid nitrogen vaporization system implements full-automatic startup and shutdown and safety interlocking protection. When one of the individual devices fails, the controller can automatically stop the failure device and switch to the redundancy device thereof, thereby avoiding the shutdown of the entire system caused by a local fault, and enhancing the operation stability of the system. In addition, operation parameters can also be automatically adjusted according to the required gas quantity and pressure, so that the automation degree is high, and efficient, stable and safe operation is realized.

Description

A liquid nitrogen vaporization system Technical Field

[0001] The utility model belongs to the technical field of nitrogen supply, and in particular relates to a liquid nitrogen vaporization system. Background Art

[0002] Conventional liquid nitrogen vaporization equipment is usually used as a backup system (public works) for air-pressure nitrogen production systems or as a supporting system for other nitrogen-consuming processes. It is mainly composed of liquid nitrogen tanks, liquid nitrogen booster pumps, vaporizers, heaters, buffer tanks and other major equipment and pipelines, instruments, manual valves, etc.

[0003] However, the existing liquid nitrogen vaporization device still has the following problems:

[0004] (1) During operation, if a single device in the device fails, the entire device will be shut down, which will have a great impact on the operation of downstream nitrogen-using equipment;

[0005] (2) It is impossible to achieve automatic start and stop and adjustment of operating parameters. When there are different gas consumption and pressure requirements downstream, manual intervention is required, and the demand for on-site operators is high. Once there is a shortage of on-site personnel, the operation of downstream nitrogen equipment will be difficult to carry out. Technical Solutions

[0006] In response to the problems of local failures in conventional liquid nitrogen vaporization devices leading to overall shutdown and inability to automatically adjust parameters, the utility model provides a liquid nitrogen vaporization system. By configuring redundant equipment for important single equipment such as liquid nitrogen storage tanks, boosters, vaporizers, heaters, etc., and adding controllers electrically connected to each single equipment, each valve body and measuring instruments, the system monitors the operating status and parameter changes of each equipment in real time. A fully automatic control program is set in the controller, and each single equipment and switch valve can operate according to the fully automatic control program. Safety interlock protection can also be implemented. When a single equipment fails, it automatically switches to its redundant equipment, avoiding the problem of local failures leading to overall system shutdown. The system has a high degree of automation and can automatically adjust parameters according to demand, reducing on-site manual intervention and on-site personnel, and improving the reliability of continuous operation of the system as well as the safety and stability of gas supply.

[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A liquid nitrogen vaporization system, comprising: a liquid nitrogen supply unit, a vaporization device, a heater, a buffer tank, a nitrogen output pressure regulating device, and a controller connected in sequence; the liquid nitrogen supply units are at least two, and a plurality of the liquid nitrogen supply units are arranged in parallel; the liquid nitrogen supply unit comprises a liquid nitrogen storage tank, a booster device, a liquid nitrogen supply pipeline, a return air pipeline, and an overpressure return liquid pipeline; the liquid nitrogen storage tank is provided with a liquid nitrogen outlet, a return air inlet, and a return liquid inlet; the booster device is provided with a liquid nitrogen inlet, a first outlet, and a second outlet, the first outlet is connected to the inlet of the vaporization device; the two ends of the liquid nitrogen supply pipeline are respectively connected to the liquid nitrogen outlet and the liquid nitrogen inlet; the two ends of the return air pipeline are respectively connected to the liquid nitrogen outlet and the liquid nitrogen inlet; The ends are respectively connected to the second outlet and the return gas inlet; one end of the overpressure liquid return pipeline is arranged on the pipeline between the first outlet and the inlet of the vaporizer, and the other end is connected to the liquid return inlet; the nitrogen output pressure regulating device is used to regulate the nitrogen in the buffer tank to the pressure required by the downstream nitrogen-using equipment; the controller is electrically connected to the boosting device, the vaporizer, the heater and the nitrogen output pressure regulating device, respectively, and is used to control the opening and closing and opening degree of the liquid nitrogen inlet, the first outlet and the second outlet, and control the start and stop and operating parameters of the vaporizer, the heater and the nitrogen output pressure regulating device.

[0009] In some embodiments, the liquid nitrogen supply unit is further provided with a first pressure sensor, which is arranged on the pipeline between the first outlet and the inlet of the vaporizer, and the first pressure sensor is electrically connected to the controller, and the first pressure sensor is used to detect the pressure of the liquid nitrogen input into the vaporizer.

[0010] In some embodiments, the liquid nitrogen supply unit is further provided with a first pressure regulating valve, which is arranged on the pipeline between the first pressure sensor and the inlet of the vaporization device, and the first pressure regulating valve is used to control the pressure of the liquid nitrogen input into the vaporization device.

[0011] In some embodiments, a liquid nitrogen inlet switch valve is provided on the liquid nitrogen supply pipeline, a return air switch valve is provided on the return air pipeline, and an overpressure return liquid switch valve is provided on the overpressure return liquid pipeline; the liquid nitrogen inlet switch valve, the return air switch valve, and the overpressure return liquid switch valve are electrically connected to the controller respectively.

[0012] In some embodiments, multiple liquid supply switching pipelines, multiple return air switching pipelines and multiple overpressure return liquid switching pipelines, any two of the liquid nitrogen supply pipelines are connected through the liquid supply switching pipeline, and a liquid supply switching switch valve is provided on the liquid supply switching pipeline; any two of the return air pipelines are connected through the return air switching pipeline, and a return air switching switch valve is provided on the return air switching pipeline; any two of the overpressure return liquid pipelines are connected through the overpressure return liquid switching pipeline, and an overpressure return liquid switching switch valve is provided on the overpressure return liquid switching pipeline; the liquid supply switching switch valve, the return air switching switch valve and the overpressure return liquid switching switch valve are electrically connected to the controller respectively.

[0013] In some embodiments, a plurality of pressure gauges and a plurality of flow meters are further provided, and the pressure gauges and the flow meters are provided on the liquid nitrogen storage tank, the buffer tank, the liquid nitrogen supply pipeline, the return air pipeline, the overpressure return liquid pipeline, and the pipeline between the buffer tank and the nitrogen output pressure regulating device; the pressure gauges and the flow meters are electrically connected to the controller, respectively.

[0014] In some embodiments, a plurality of temperature sensors are further provided, and the temperature sensors are all provided on the liquid nitrogen storage tank, the boosting device, the liquid nitrogen supply pipeline, the return air pipeline, the vaporization device and the heater; the temperature sensors are electrically connected to the controller.

[0015] In some embodiments, the vaporization device includes multiple vaporizers arranged in parallel, the inlet of the vaporizer is connected to the first outlet, and the outlet of the vaporizer is connected to the heater; a vaporizer switching valve is provided on the pipeline between the inlet of any vaporizer and the first outlet, and the vaporizer switching valve is electrically connected to the controller.

[0016] In some embodiments, there are multiple heaters, and the multiple heaters are arranged in parallel; there are multiple buffer tanks, and the multiple buffer tanks are arranged in parallel. Beneficial effects

[0017] In some embodiments, the vaporization device is an air-temperature vaporizer.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The liquid nitrogen vaporization system provided by the present invention configures redundant equipment for important single equipment (such as liquid nitrogen storage tanks, boosters, vaporizers, heaters, etc.). When one of the single equipment fails, the controller can automatically shut down the failed equipment and switch to its redundant equipment, avoiding the problem of local failure causing the entire system to stop working, thereby enhancing the reliability of the continuous operation of the system;

[0020] 2. The liquid nitrogen vaporization system is equipped with a controller, which is electrically connected to each individual device, pressure gauge, pipeline switch valve, etc. A fully automatic control program is set in the controller, and each individual device and switch valve can operate according to the fully automatic control program. At the same time, the controller monitors the operating status and parameter changes of each device in real time, realizes fully automatic start, shutdown and safety interlock protection, and has stable operation. It can also automatically adjust the operating parameters according to the gas demand and pressure of the downstream nitrogen-using device. When a single device fails, it automatically switches to its redundant equipment, which does not affect the overall operation process of the system. The controller has a high degree of automation and reduces personnel investment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] FIG1 is a schematic structural diagram of a liquid nitrogen vaporization system provided by the present invention;

[0023] FIG2 is a schematic structural diagram of a conventional liquid nitrogen vaporization device in the prior art.

[0024] The meanings of the symbols in the accompanying drawings are as follows:

[0025] 1—liquid nitrogen storage tank; 101—liquid nitrogen outlet; 102—return air inlet; 103—return liquid inlet;

[0026] 2—boosting device; 201—liquid nitrogen inlet; 202—first outlet; 203—second outlet;

[0027] 3—Liquid nitrogen supply pipeline; 301—Liquid nitrogen inlet switch valve;

[0028] 4—return air pipeline; 401—return air switch valve;

[0029] 5—overpressure liquid return pipeline; 501—overpressure liquid return switch valve;

[0030] 6—Liquid supply switching pipeline; 601—Liquid supply switching valve;

[0031] 7—return air switching pipeline; 701—return air switching valve;

[0032] 8—Overpressure return liquid switching pipeline 801—Overpressure return liquid switching valve;

[0033] 9—Carburetor; 901—Carburetor switching valve;

[0034] 10—heater;

[0035] 11—buffer tank;

[0036] 12—Nitrogen output pressure regulating device;

[0037] 13—first pressure sensor; 14—first pressure regulating valve. Modes for Carrying Out the Invention

[0038] The present invention will be further explained in detail below in conjunction with the drawings and descriptions of specific embodiments. However, the following descriptions including the embodiments are only intended to enable ordinary technicians in the technical field to which the present invention belongs to more clearly understand the principles and essence of the present invention, and do not mean to limit the present invention in any form.

[0039] Figure 2 shows a conventional liquid nitrogen vaporization device in the prior art, which includes a liquid nitrogen storage tank 1, a booster device 2, a vaporizer 9, a heater 10 and a buffer tank 11 connected in sequence. The liquid nitrogen stored in the liquid nitrogen storage tank 1 is pressurized by the booster device 2 and flows into the vaporizer 9. The liquid nitrogen is vaporized into nitrogen gas, which is then heated and stored in the buffer tank 11 to be supplied to the downstream nitrogen-using device.

[0040] However, during actual operation, if one of the devices fails, such as the vaporizer 9, causing the liquid nitrogen to be unable to vaporize, and thus unable to supply nitrogen to the downstream nitrogen-using device, or if the liquid nitrogen storage tank 1 or the booster device 2 fails, the entire device will be shut down.

[0041] In addition, when the downstream nitrogen-using device requires different gas volumes and pressures, the liquid nitrogen vaporization device cannot automatically adjust the gas pressure and parameters, requiring manual intervention, which places high demands on the operation of on-site personnel. To address the shortcomings of the above-mentioned conventional liquid nitrogen vaporization device, the present invention provides a liquid nitrogen vaporization system, which is as follows:

[0042] As shown in FIG1 , the liquid nitrogen vaporization system provided by the present invention includes: a liquid nitrogen supply unit, a vaporization device, a heater 10 , a buffer tank 11 , a nitrogen output pressure regulating device 12 , and a controller connected in sequence.

[0043] The liquid nitrogen supply unit includes a liquid nitrogen storage tank 1, a pressurizing device 2, a liquid nitrogen supply pipeline 3, a gas return pipeline 4 and an overpressure liquid return pipeline 5.

[0044] The number of the liquid nitrogen supply units is not limited, and is at least two, with multiple liquid nitrogen supply units arranged in parallel. Preferably, two liquid nitrogen supply units are arranged, one for use and one for backup.

[0045] The liquid nitrogen storage tank 1 is provided with a liquid nitrogen outlet 101 , a return air inlet 102 and a return liquid inlet 103 .

[0046] The boosting device 2 is provided with a liquid nitrogen inlet 201 , a first outlet 202 and a second outlet 203 , and the first outlet 202 is connected to the inlet of the vaporizing device.

[0047] The two ends of the liquid nitrogen supply pipeline 3 are respectively connected to the liquid nitrogen outlet 101 and the liquid nitrogen inlet 201. The liquid nitrogen in the liquid nitrogen storage tank 1 flows out from the liquid nitrogen outlet 101, enters the boosting device 2 through the liquid nitrogen inlet 201 for boosting, and the boosted liquid nitrogen enters the vaporization device from the first outlet 202 for vaporization.

[0048] Both ends of the return air pipeline 4 are connected to the second outlet 203 and the return air inlet 102 respectively.

[0049] One end of the overpressure liquid return pipeline 5 is provided on the pipeline between the first outlet 202 and the inlet of the vaporization device, and the other end of the overpressure liquid return pipeline 5 is connected to the liquid return inlet 103 .

[0050] The nitrogen output pressure regulating device 12 is used to regulate the nitrogen in the buffer tank 11 to the pressure required by the downstream nitrogen-using equipment.

[0051] More preferably, an outlet flow regulating valve is further provided on the pipeline between the nitrogen output pressure regulating device 12 and the downstream nitrogen-using equipment, and the outlet flow regulating valve is used to regulate the nitrogen flow input to the downstream nitrogen-using equipment.

[0052] The basic operating process of the system is as follows: the liquid nitrogen stored in the liquid nitrogen storage tank 1 is pressurized by the booster device 2, and then enters the vaporizer, where the liquid nitrogen is vaporized into nitrogen gas. The nitrogen gas is then reheated to room temperature by the heater 10 and passed into the buffer tank 10 for buffering. The output pressure regulating device 6 then regulates the pressure to the pressure required by the downstream nitrogen-using device before output.

[0053] The controller is electrically connected to the boosting device 2, the vaporizing device, the heater 10 and the nitrogen output pressure regulating device 12, respectively. The controller is used to control the opening and closing and the opening degree of the liquid nitrogen inlet 201, the first outlet 202 and the second outlet 203, respectively, and to control the start and stop and operating parameters of the vaporizing device, the heater 10 and the nitrogen output pressure regulating device 12.

[0054] The controller is also electrically connected to the outlet flow control valve, automatically adjusting operating parameters based on the gas demand of downstream nitrogen users, allowing gas supply to meet short-term, large-scale or daily average usage. When buffer tank 11 stores high-pressure nitrogen and downstream gas demand is stable, i.e., during normal operation, the outlet flow control valve opening is relatively fixed, and the system operates in a steady-state operation with daily average demand. When downstream gas demand increases, the system can timely replenish nitrogen based on downstream user needs by controlling the outlet flow control valve opening, increasing the nitrogen flow to the downstream nitrogen users. At this time, the pressure in buffer tank 11 may decrease.

[0055] In some embodiments, the vaporization device includes a plurality of vaporizers 9 arranged in parallel, an inlet of the vaporizer 9 is connected to the first outlet 202 , and an outlet of the vaporizer 9 is connected to the heater 10 .

[0056] A vaporizer switching valve 901 is provided on the pipeline between the inlet of any vaporizer 9 and the first outlet 202. The vaporizer switching valve 901 is electrically connected to the controller. When a vaporizer 9 fails, vaporization can be switched to other vaporizers 9 through the vaporizer switching valve 901.

[0057] Preferably, the vaporizer 9 can be an air-temperature vaporizer or a water-bath vaporizer. However, when a water-bath vaporizer is used, the heater 10 can be omitted.

[0058] In some embodiments, there may be multiple heaters 10 , and the multiple heaters 10 are arranged in parallel. Preferably, two heaters 10 are arranged, one for use and one for backup.

[0059] There may be multiple buffer tanks 11 , and the multiple buffer tanks 11 are arranged in parallel.

[0060] More preferably, the controller includes a safety interlock module, which is electrically connected to the above-mentioned individual devices such as the liquid nitrogen storage tank 1, the booster 2, the vaporizer, the heater 10, etc., and various switch valves such as the liquid nitrogen inlet switch valve 301. When an abnormal situation or failure occurs during the operation of the system, the individual or part of the devices or switch valves are automatically operated according to the set rules and requirements, so that the system enters normal operation or a safe state. For example, when the liquid nitrogen storage tank 1 in one of the liquid nitrogen supply units fails, the liquid nitrogen supply pipeline 3 and the booster 2 connected to the liquid nitrogen storage tank 1 are immediately stopped, the supply of liquid nitrogen is stopped, and the liquid nitrogen supply unit connected in parallel with it is opened to continue supplying gas.

[0061] In summary, in the liquid nitrogen vaporization system provided in the present application, by configuring redundant equipment for important single devices (such as liquid nitrogen storage, booster devices, vaporizers, heaters, etc.), when one of the single devices fails, the controller can automatically shut down the failed device and switch to its redundant equipment, avoiding the problem of local failures causing the entire system to stop working, thereby enhancing the reliability of the continuous operation of the system.

[0062] In some embodiments, a liquid nitrogen inlet switch valve 301 is provided on the liquid nitrogen supply pipeline 3, a return air switch valve 401 is provided on the return air pipeline 4, and an overpressure return liquid switch valve 501 is provided on the overpressure return liquid pipeline 5. The liquid nitrogen inlet switch valve 301, the return air switch valve 401 and the overpressure return liquid switch valve 501 are respectively electrically connected to the controller.

[0063] In some embodiments, the liquid nitrogen supply unit further includes a first pressure sensor 13 , which is disposed in the pipeline between the first outlet 202 and the inlet of the vaporizer. The first pressure sensor 13 is electrically connected to a controller and is configured to detect the pressure of the liquid nitrogen input to the vaporizer. When the first pressure sensor 13 detects that the pressure in the pipeline between the first outlet 202 and the inlet of the vaporizer exceeds a set pressure, the controller controls the overpressure liquid return valve 501 to open, allowing the overpressure portion of the liquid nitrogen to return to the liquid nitrogen storage tank 1 via the overpressure liquid return pipeline 5 , thereby promptly regulating pressure fluctuations.

[0064] Preferably, the liquid nitrogen supply unit is further provided with a first pressure regulating valve 14, which is arranged on the pipeline between the first pressure sensor 13 and the inlet of the vaporizer. The first pressure regulating valve 14 is used to control or maintain the pressure of the liquid nitrogen input to the vaporizer. When the pressure fluctuation detected by the first pressure sensor 13 is small, the first pressure regulating valve 14 can be used to appropriately regulate the pressure of the liquid nitrogen entering the vaporizer.

[0065] In some embodiments, the controller may specifically be a programmable logic controller (PLC), or other forms of processors and their memories, which are not specifically limited here and are all within the scope of protection of this application.

[0066] More preferably, the liquid nitrogen vaporization system further comprises a display screen, which is electrically connected to the controller for facilitating the operator to set various equipment parameters and display the operating status of the liquid nitrogen vaporization system.

[0067] In some embodiments, the liquid nitrogen vaporization system further includes a plurality of liquid supply switching pipelines 6 , a plurality of gas return switching pipelines 7 , and a plurality of overpressure liquid return switching pipelines 8 .

[0068] Any two liquid nitrogen supply pipelines 3 are connected via a liquid supply switching pipeline 6 , and a liquid supply switching valve 601 is provided on the liquid supply switching pipeline 6 .

[0069] Any two return air pipelines 4 are connected via a return air switching pipeline 7 , and a return air switching valve 701 is provided on the return air switching pipeline 7 .

[0070] Any two overpressure liquid return pipelines 5 are connected through an overpressure liquid return switching pipeline 8 , and an overpressure liquid return switching valve 801 is provided on the overpressure liquid return switching pipeline 8 .

[0071] The liquid supply switching valve 601 , the air return switching valve 701 and the overpressure liquid return switching valve 801 are electrically connected to the controller respectively.

[0072] To illustrate the functions of the liquid supply switching pipeline 6, the return gas switching pipeline 7, and the overpressure return liquid switching pipeline 8, two parallel liquid nitrogen supply units are provided here, one of which includes a liquid nitrogen storage tank A, a liquid nitrogen storage tank A, a booster device A, a liquid nitrogen supply pipeline A, a return gas pipeline A, an overpressure return liquid pipeline A, and a vaporizer A; the other liquid nitrogen supply unit includes a liquid nitrogen storage tank B, a booster device B, a liquid nitrogen supply pipeline B, a return gas pipeline B, an overpressure return liquid pipeline B, and a vaporizer B. The connection method of each device and the pipeline here is the same as shown above and will not be repeated here.

[0073] Furthermore, liquid nitrogen supply pipeline A and liquid nitrogen supply pipeline B are connected through a liquid supply switching pipeline C, which is provided with a liquid supply switching valve C. When the amount of liquid nitrogen in liquid nitrogen storage tank A is insufficient, the liquid supply switching valve C can be opened to use the liquid nitrogen in the other liquid nitrogen storage tank B to supply liquid to vaporizer A.

[0074] The return gas pipeline A and the return gas pipeline B are connected through the return gas switching pipeline C, which is provided with a return gas switching valve C. When the pressure of the liquid nitrogen storage tank A reaches the set tank pressure, or the amount of liquid nitrogen in the liquid nitrogen storage tank A reaches the maximum tank capacity, the return gas switching valve C can be opened to pass the liquid nitrogen to be returned to the liquid nitrogen storage tank A into the other liquid nitrogen storage tank B.

[0075] Overpressure return liquid pipeline A and overpressure return liquid pipeline B are connected through an overpressure return liquid switching pipeline C, which is equipped with an overpressure return liquid switching valve C. When overpressure occurs between the first outlet of the booster device A and the inlet of the vaporizer device A, if the pressure of the liquid nitrogen storage tank A reaches the set tank pressure, or the amount of liquid nitrogen in the liquid nitrogen storage tank A reaches the maximum tank capacity, the overpressure return liquid switching valve C can be opened to pass the liquid nitrogen to be returned to the liquid nitrogen storage tank A into another liquid nitrogen storage tank B.

[0076] In some embodiments, the liquid nitrogen vaporization system is further equipped with multiple pressure gauges and multiple flow meters. Pressure gauges and flow meters are installed on the liquid nitrogen storage tank 1, the buffer tank 11, the liquid nitrogen supply line 3, the return air line 4, the overpressure return liquid line 5, the liquid supply switching line 6, the return air switching line 7, the overpressure return liquid switching line 8, and the pipeline between the buffer tank 11 and the nitrogen output pressure regulating device 12. The multiple pressure gauges and flow meters are electrically connected to the controller.

[0077] In some embodiments, the liquid nitrogen vaporization system is provided with a plurality of temperature sensors, and temperature sensors for detecting temperature are provided on the liquid nitrogen storage tank 1, the boosting device 2, the liquid nitrogen supply line 3, the return air line 4, the vaporization device and the heater 10. The above-mentioned plurality of temperature sensors are electrically connected to the controller respectively.

[0078] In some embodiments, the parameters of each device in the above-mentioned liquid nitrogen vaporization system are:

[0079] (1) The working pressure of liquid nitrogen storage tank 1 is 0-1 MPag. The storage capacity of a single liquid nitrogen storage tank 1 needs to be configured according to user needs.

[0080] (2) The booster device 2 can use a booster pump. The pressure of the liquid nitrogen inlet 201 is 0-1 MPag, the rated flow rate is 1000-20000 Nm3 / h (needs to be configured according to user needs), and the first outlet pressure is 1-3 MPag (needs to be configured according to user needs).

[0081] (3) Vaporizer 9: operating pressure is 1-3 MPag (needs to be configured according to user needs), outlet temperature is ≥ ambient temperature -20 °C, nitrogen flow rate is 1000-20000 Nm3 / h (needs to be configured according to user needs).

[0082] (4) Heater 10: The operating pressure is 1-3 MPag (needs to be configured according to user needs), and the outlet temperature is room temperature or configured according to user needs.

[0083] (5) Buffer tank 11: The operating pressure is 1-3 MPag (needs to be configured according to user needs). The gas storage capacity of buffer tank 11 needs to be configured according to user needs.

[0084] (6) Nitrogen output pressure regulating device 12: Reduces the pressure to the actual downstream required pressure. It can be one or more sets with multiple pressure regulating levels to meet the gas supply needs of the downstream low-pressure nitrogen device and the downstream medium-pressure nitrogen device.

[0085] The liquid nitrogen supply unit includes three operating modes, specifically:

[0086] (1) Start-up process

[0087] After the liquid nitrogen storage tank 1 is filled with liquid nitrogen and various parameters such as pressure, temperature, and liquid level are set, the operator clicks the "Start" button on the display, and the controller controls the liquid nitrogen inlet switch valve 301 and the return air switch valve 401 to open. The liquid nitrogen will automatically enter the boosting device 2 from the liquid nitrogen supply pipeline 3, pre-cool the boosting device 2 and various pipelines, and then return to the liquid nitrogen storage tank 1 through the return air pipeline 4.

[0088] When the controller determines that the pre-cooling operation is completed through the temperature and the liquid nitrogen storage tank 1 reaches the set pressure, the controller controls the return air switch valve 401 to close, and the liquid nitrogen supply pipeline 3 continues to transport liquid nitrogen to the boosting device 2. At the same time, the boosting device 2 is started to increase the pressure and transports liquid nitrogen to the vaporization device through the first outlet 202.

[0089] The vaporized nitrogen is heated by the heater 10 and then enters the buffer tank 11. When the pressure of the buffer tank 11 reaches the set value, the controller determines that the liquid nitrogen vaporization system has been started and can enter the normal operation state, and then opens the nitrogen output pressure regulating device 12 to supply gas to the downstream nitrogen-using device.

[0090] (2) Normal operation process

[0091] During normal operation, the downstream nitrogen-using device and each pipeline are equipped with pressure transmitters, and the controller can also be electrically connected to these pressure transmitters. When the gas pressure changes, the controller receives the electrical signal from the pressure transmitter and converts it into a control signal for the nitrogen output pressure regulating device 12, and promptly controls the nitrogen output pressure regulating device 12 to adjust the pressure of the output nitrogen to meet the downstream gas demand.

[0092] When the gas demand of the downstream nitrogen-using device changes, the controller automatically controls the nitrogen output pressure regulating device 12 and the outlet flow regulating valve to adjust the pressure and flow of the output nitrogen to meet the downstream gas demand.

[0093] The pressure fluctuation generated in the pipeline between the first outlet 202 and the inlet of the vaporization device can be adjusted by opening the overpressure liquid return switching valve 801 and the first pressure regulating valve 14.

[0094] The controller can monitor the operating parameters at any time. When a single device fails, that is, when the interlock setting value in the controller is reached, interlock protection will be activated, and redundant equipment will be switched to continue operation or stop, realizing automatic operation.

[0095] (3) Parking operation process

[0096] The operator can issue a remote command and click the "Stop" button on the display, and the running booster device 2 will be shut down immediately, the first outlet 202 will be closed, and the switch valves on each pipeline will be closed at the same time.

[0097] Operators can perform maintenance and repairs on equipment such as liquid nitrogen supply units and vaporization devices.

[0098] In summary, this application adds a controller and electrically connects the controller with each individual device, pressure gauge, pipeline switch valve, etc. A fully automatic control program is set in the controller to monitor the operating status and parameter changes of each device in real time, thereby realizing fully automatic start-up, operation and shutdown of the system. The operating parameters of the device can be automatically adjusted according to the gas demand and pressure of the downstream nitrogen-using device, reducing the demand for operators for conventional liquid nitrogen vaporization equipment. At the same time, safety interlock protection and redundant equipment are also set to ensure the stability of system operation.

[0099] The ideal embodiment of the present invention is for inspiration. Through the above description, relevant personnel can make various changes and modifications without departing from the scope of the technical idea of ​​the present invention.

[0100] The technical scope of this utility model is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A liquid nitrogen vaporization system, characterized in that: include: A liquid nitrogen supply unit, a vaporizing device, a heater, a buffer tank, a nitrogen output pressure regulating device, and a controller connected in sequence; There are at least two liquid nitrogen supply units, and a plurality of the liquid nitrogen supply units are arranged in parallel; The liquid nitrogen supply unit comprises a liquid nitrogen storage tank, a pressurizing device, a liquid nitrogen supply pipeline, a gas return pipeline and an overpressure liquid return pipeline; The liquid nitrogen storage tank is provided with a liquid nitrogen outlet, a gas return inlet and a liquid return inlet; The booster device is provided with a liquid nitrogen inlet, a first outlet and a second outlet, wherein the first outlet is connected to the inlet of the vaporization device; Two ends of the liquid nitrogen supply pipeline are respectively connected to the liquid nitrogen outlet and the liquid nitrogen inlet; The two ends of the return air pipeline are respectively connected to the second outlet and the return air inlet; One end of the overpressure liquid return pipeline is arranged on the pipeline between the first outlet and the inlet of the vaporization device, and the other end is connected to the liquid return inlet; The nitrogen output pressure regulating device is used to adjust the nitrogen in the buffer tank to the pressure required by the downstream nitrogen-using equipment; The controller is electrically connected to the pressurizing device, the vaporizing device, the heater and the nitrogen output pressure regulating device, respectively, and is used to control the opening and closing and the opening degree of the liquid nitrogen inlet, the first outlet and the second outlet, respectively, and control the start and stop and operating parameters of the vaporizing device, the heater and the nitrogen output pressure regulating device.

2. The liquid nitrogen vaporization system according to claim 1, characterized in that: The liquid nitrogen supply unit is further provided with a first pressure sensor, which is arranged on a pipeline between the first outlet and the inlet of the vaporizer, and is electrically connected to the controller, and is used to detect the pressure of the liquid nitrogen input into the vaporizer.

3. The liquid nitrogen vaporization system according to claim 2, characterized in that: The liquid nitrogen supply unit is further provided with a first pressure regulating valve, which is arranged on a pipeline between the first pressure sensor and the inlet of the vaporizing device, and is used to control the pressure of the liquid nitrogen input into the vaporizing device.

4. The liquid nitrogen vaporization system according to claim 1, characterized in that: The liquid nitrogen supply pipeline is provided with a liquid nitrogen inlet switch valve, the air return pipeline is provided with an air return switch valve, and the overpressure liquid return pipeline is provided with an overpressure liquid return switch valve; The liquid nitrogen inlet switch valve, the air return switch valve and the overpressure liquid return switch valve are electrically connected to the controller respectively.

5. The liquid nitrogen vaporization system according to claim 1, characterized in that: Also includes: Multiple liquid supply switching pipelines, multiple air return switching pipelines and multiple overpressure liquid return switching pipelines, Any two of the liquid nitrogen supply pipelines are connected through the liquid supply switching pipeline, and the liquid supply switching pipeline is provided with a liquid supply switching valve; Any two of the return air pipelines are connected via the return air switching pipeline, and a return air switching switch valve is provided on the return air switching pipeline; Any two of the overpressure liquid return pipelines are connected through the overpressure liquid return switching pipeline, and the overpressure liquid return switching pipeline is provided with an overpressure liquid return switching valve; The liquid supply switching valve, the air return switching valve and the overpressure liquid return switching valve are electrically connected to the controller respectively.

6. The liquid nitrogen vaporization system according to claim 1, characterized in that: There are also multiple pressure gauges and flow meters. The pressure gauge and the flow meter are provided on the liquid nitrogen storage tank, the buffer tank, the liquid nitrogen supply pipeline, the gas return pipeline, the overpressure liquid return pipeline, and the pipeline between the buffer tank and the nitrogen output pressure regulating device; The pressure meter and the flow meter are electrically connected to the controller respectively.

7. The liquid nitrogen vaporization system according to claim 1, characterized in that: A plurality of temperature sensors are also provided, and the temperature sensors are all provided on the liquid nitrogen storage tank, the booster device, the liquid nitrogen supply pipeline, the return air pipeline, the vaporization device and the heater; The temperature sensor is electrically connected to the controller.

8. The liquid nitrogen vaporization system according to claim 1, characterized in that: The vaporization device comprises a plurality of vaporizers arranged in parallel, the inlet of the vaporizer is connected to the first outlet, and the outlet of the vaporizer is connected to the heater; A carburetor switching valve is provided on the pipeline between the inlet of any carburetor and the first outlet, and the carburetor switching valve is electrically connected to the controller.

9. The liquid nitrogen vaporization system according to claim 1, characterized in that: The number of the heaters is multiple, and the multiple heaters are arranged in parallel; There are multiple buffer tanks, and the multiple buffer tanks are arranged in parallel.

10. The liquid nitrogen vaporization system according to claim 7, characterized in that: The vaporization device is an air-temperature vaporizer.

Images