A cryogenic liquid pumpable transfer system with controllable cavitation

Abstract

The present application relates to the technical fields of low-temperature liquid transmission, and relates to a low-temperature liquid pump cavitation-controllable transmission system, comprising: a low-temperature liquid source, a low-temperature liquid pump connected with a low-temperature liquid source pipeline for conveying low-temperature liquid, a refrigeration system for cooling low-temperature fluid flowing from the low-temperature liquid source to the low-temperature liquid pump, and a control system connected with the refrigeration system, wherein the control system can receive real-time pressure and temperature feedback signals of the low-temperature fluid, and dynamically adjust the supply amount of cold energy or the temperature zone of the refrigeration system according to the feedback signals, so as to eliminate or reduce cavitation; through the setting of the cooling system and the control system, the control system can accurately adjust the cold energy output of the refrigeration system based on real-time pressure and temperature feedback, so as to ensure that the low-temperature fluid is always in a safe interval at the pump inlet, thereby eliminating or reducing the cavitation phenomenon of the low-temperature liquid pump, and ensuring the long-term stable operation of the transmission system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-temperature transmission systems, in particular to a low-temperature liquid pump cavitation-controllable transmission system. BACKGROUND

[0002] In many industrial and scientific fields, the transmission of low-temperature liquids is a key technical link, and low-temperature liquid pumps play a core role in it. For example, in the storage and transportation of liquefied natural gas (LNG), the application of liquid hydrogen, etc., it is necessary to efficiently and safely transport low-temperature liquids from the storage container to the designated location.

[0003] However, for a long time, cavitation has been a serious challenge faced by low-temperature liquid pumps. When low-temperature liquids flow in the pump, due to the local pressure being reduced below the saturated vapor pressure of the liquid, gas bubbles are formed, which rapidly collapse in high-pressure areas, producing strong impact and vibration, not only reducing the efficiency of the pump, but also causing serious erosion and damage to the internal structure of the pump, greatly affecting the stability and reliability of the low-temperature liquid transmission system. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a low-temperature liquid pump cavitation-controllable transmission system, aiming to solve the problem that the cavitation of low-temperature liquids in the prior art not only reduces the efficiency of the pump, but also causes serious erosion and damage to the internal structure of the pump, greatly affecting the stability and reliability of the low-temperature liquid transmission system.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solution: a low-temperature liquid pump cavitation-controllable transmission system, characterized in that it comprises a low-temperature liquid source, a low-temperature liquid pump connected with the low-temperature liquid source pipeline for transporting low-temperature liquids, a refrigeration system for refrigerating low-temperature fluids flowing from the low-temperature liquid source to the low-temperature liquid pump, a control system connected with the refrigeration system, the control system can receive real-time pressure and temperature feedback signals of the low-temperature fluids, and dynamically adjust the supply amount of cold energy or the temperature zone of the refrigeration system according to the feedback signals, so as to realize the elimination or mitigation of cavitation.

[0006] Further, the control system is connected with the low-temperature liquid pump, and the control system can receive real-time cavitation state of the low-temperature liquid pump, and dynamically control the fluid delivery flow of the low-temperature fluid pump according to the cavitation state of the low-temperature liquid pump.

[0007] Further, the control system is provided with a storage module and a control module, the storage module stores the saturation temperature-pressure relationship data of the low-temperature liquid and the temperature-pressure diagram data of the pump without cavitation; the control system is further provided with a plurality of sensors for acquiring the pressure parameter P of the low-temperature fluid and the measured temperature T1 of the low-temperature liquid; the control module can calculate the corresponding saturation temperature T2 from the acquired pressure parameter P according to the saturation temperature-pressure relationship data in the storage module, and determine the required inlet temperature T3 of the pump inlet according to the stored temperature-pressure diagram data of the pump without cavitation; when cavitation occurs, the control module implements at least one of the following control measures according to the measured temperature T1 of the low-temperature liquid, the flow of the refrigeration system and the determined required inlet temperature T3 of the pump inlet: reducing the fluid delivery flow of the low-temperature fluid pump, increasing the supply of cold energy of the refrigeration system, adjusting the temperature zone of the cold energy of the refrigeration system, so as to eliminate or reduce the cavitation of the low-temperature liquid pump.

[0008] Further, the control system is provided with a storage module and a control module, the storage module stores the saturation temperature-pressure relationship data of the low-temperature liquid and the temperature-pressure diagram data of the pump without cavitation; the control system is further provided with a plurality of sensors for acquiring the pressure parameter P of the low-temperature fluid and the measured temperature T1 of the low-temperature liquid; the control module can calculate the corresponding saturation temperature T2 from the acquired pressure parameter P according to the saturation temperature-pressure relationship data in the storage module, and determine the required inlet temperature T3 of the pump inlet according to the stored temperature-pressure diagram data of the pump without cavitation; when cavitation occurs, the control module implements at least one of the following control measures according to the measured temperature T1 of the low-temperature liquid, the flow of the refrigeration system and the determined required inlet temperature T3 of the pump inlet: reducing the fluid delivery flow of the low-temperature fluid pump, increasing the supply of cold energy of the refrigeration system, adjusting the temperature zone of the cold energy of the refrigeration system, so as to eliminate or reduce the cavitation of the low-temperature liquid pump.

[0009] Further, the control system is provided with a storage module and a control module, the storage module stores the saturation temperature-pressure relationship data of the low-temperature liquid and the temperature-pressure diagram data of the pump without cavitation; the control system is further provided with a plurality of sensors for acquiring the pressure parameter P of the low-temperature fluid and the measured temperature T1 of the low-temperature liquid; the control module can calculate the corresponding saturation temperature T2 from the acquired pressure parameter P according to the saturation temperature-pressure relationship data in the storage module, and determine the required inlet temperature T3 of the pump inlet according to the stored temperature-pressure diagram data of the pump without cavitation; when cavitation occurs, the control module implements at least one of the following control measures according to the measured temperature T1 of the low-temperature liquid, the flow of the refrigeration system and the determined required inlet temperature T3 of the pump inlet: reducing the fluid delivery flow of the low-temperature fluid pump, increasing the supply of cold energy of the refrigeration system, adjusting the temperature zone of the cold energy of the refrigeration system, so as to eliminate or reduce the cavitation of the low-temperature liquid pump.

[0010] Further, the refrigeration system comprises a compressor, a cooler, a multi-stream heat exchanger and an expander; the outlet of the compressor is connected with the inlet pipeline of the cooler, the outlet of the cooler is connected with the first inlet pipeline of the multi-stream heat exchanger, the first outlet of the multi-stream heat exchanger corresponding to the first inlet is connected with the inlet pipeline of the expander, the outlet of the expander is connected with the second inlet pipeline of the multi-stream heat exchanger, the second outlet of the multi-stream heat exchanger corresponding to the second inlet is connected with the inlet pipeline of the compressor, and the multi-stream heat exchanger further comprises a third inlet and a third outlet, the third inlet is connected with the outlet pipeline of the low-temperature liquid source, and the third outlet is connected with the inlet pipeline of the low-temperature liquid pump.

[0011] Further, the low-temperature liquid source is a low-temperature liquid tank internally storing low-temperature liquid.

[0012] Further, the compressor is a centrifugal impeller compressor, and the expander is a centrifugal impeller expander or a low-temperature throttle valve.

[0013] Further, the control system is provided with a storage module and a control module, the storage module stores the saturation temperature-pressure relationship data of the low-temperature liquid and the temperature-pressure diagram data of the pump without cavitation; the control system is further provided with a plurality of sensors for acquiring the pressure parameter P of the low-temperature fluid and the measured temperature T1 of the low-temperature liquid; the control module can calculate the corresponding saturation temperature T2 from the acquired pressure parameter P according to the saturation temperature-pressure relationship data in the storage module, and determine the required inlet temperature T3 of the pump inlet according to the stored temperature-pressure diagram data of the pump without cavitation; when cavitation occurs, the control module implements at least one of the following control measures according to the measured temperature T1 of the low-temperature liquid, the flow of the refrigeration system and the determined required inlet temperature T3 of the pump inlet: reducing the fluid delivery flow of the low-temperature fluid pump, increasing the supply of cold energy of the refrigeration system, adjusting the temperature zone of the cold energy of the refrigeration system, so as to eliminate or reduce the cavitation of the low-temperature liquid pump.

[0014] Further, the control system is provided with a storage module and a control module, the storage module stores the saturation temperature-pressure relationship data of the low-temperature liquid and the temperature-pressure diagram data of the pump without cavitation; the control system is further provided with a plurality of sensors for acquiring the pressure parameter P of the low-temperature fluid and the measured temperature T1 of the low-temperature liquid; the control module can calculate the corresponding saturation temperature T2 from the acquired pressure parameter P according to the saturation temperature-pressure relationship data in the storage module, and determine the required inlet temperature T3 of the pump inlet according to the stored temperature-pressure diagram data of the pump without cavitation; when cavitation occurs, the control module implements at least one of the following control measures according to the measured temperature T1 of the low-temperature liquid, the flow of the refrigeration system and the determined required inlet temperature T3 of the pump inlet: reducing the fluid delivery flow of the low-temperature fluid pump, increasing the supply of cold energy of the refrigeration system, adjusting the temperature zone of the cold energy of the refrigeration system, so as to eliminate or reduce the cavitation of the low-temperature liquid pump.

[0015] The low-temperature liquid pump cavitation-controllable transmission system has the beneficial effects that: through the arrangement of the cooling system and the control system, the control system can accurately adjust the cold energy output of the refrigeration system based on real-time pressure and temperature feedback, ensure that the low-temperature fluid is always in a safe temperature and pressure interval at the pump inlet, thereby eliminating or reducing the cavitation phenomenon of the low-temperature liquid pump, and guaranteeing the long-term stable operation of the transmission system. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a flow chart of the low-temperature liquid pump cavitation-controllable transmission system of the embodiment of the present application.

[0017] The reference signs are explained as follows: 1, low-temperature liquid tank; 2, low-temperature liquid pump; 3, multi-stream heat exchanger; 4, cooler; 5, compressor; 6, expander; 7, driving device. DETAILED DESCRIPTION

[0018] The typical embodiments embodying the features and advantages of the present application will be described in detail in the following description. It should be understood that the present application can have various changes on different embodiments, which all do not deviate from the scope of the present application, and the description and drawings in the essence are used as illustration, not to limit the present application.

[0019] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0020] In order to further illustrate the principles and structures of the present application, the preferred embodiments of the present application will be described in detail in conjunction with the drawings.

[0021] As Figure 1As shown, the embodiment of the present application provides a low-temperature liquid pump 2 cavitation-controllable transmission system, comprising a low-temperature liquid source, a low-temperature liquid pump 2, a refrigeration system and a control system. Among them, the low-temperature liquid pump 2 is connected with the low-temperature liquid source through a pipeline for conveying low-temperature liquid; the refrigeration system is arranged on the pipeline between the low-temperature liquid source and the low-temperature liquid pump 2, and is used for cooling the low-temperature fluid flowing to the low-temperature liquid pump 2; the control system is connected with the refrigeration system, and real-time pressure and temperature feedback signals of the low-temperature fluid are received, and the cold energy supply or cold energy temperature zone of the refrigeration system is dynamically adjusted according to the feedback signals; when cavitation occurs, the control system can accurately adjust the cold energy output of the refrigeration system based on the real-time pressure and temperature feedback, so that the low-temperature fluid is always in a safe temperature and pressure range at the pump inlet, thereby eliminating or reducing the cavitation phenomenon of the low-temperature liquid pump 2, and ensuring the long-term stable operation of the transmission system.

[0022] Further, the above-mentioned low-temperature liquid source is a container for storing low-temperature liquid (such as liquid hydrogen, LNG, liquid oxygen, liquid nitrogen, etc.), and in the embodiment of the present application, the low-temperature liquid source is a low-temperature liquid tank 1 storing low-temperature liquid, and the outlet thereof is connected with the inlet of the low-temperature liquid pump 2 through a low-temperature and high-pressure resistant pipeline. The low-temperature liquid is conveyed to the target position under the drive of the pump.

[0023] Further, the control system is connected with the low-temperature liquid pump 2, and the control system can receive the cavitation state of the low-temperature liquid pump 2 in real time according to the cavitation state of the low-temperature liquid pump 2, and dynamically control the fluid conveying flow of the low-temperature fluid pump according to the cavitation state of the low-temperature liquid pump 2.

[0024] Specifically, the control system can judge the cavitation state of the low-temperature liquid pump 2 by real-time detection of the flow of the low-temperature liquid pump 2. Therefore, the embodiment of the present application also includes a flow sensor for detecting the inlet and outlet flow of the low-temperature fluid pump, and the flow sensor is connected with the control system, and by installing the flow sensor on the inlet and outlet pipelines of the low-temperature fluid pump, the change of the flow can be monitored. The flow anomaly caused by cavitation is often accompanied by pulsation phenomenon, and the control system analyzes the flow data collected by the flow sensor in real time, and calculates the fluctuation frequency and amplitude of the flow. If the fluctuation frequency of the flow is higher than the frequency during normal operation, and the amplitude changes greatly, it can be judged that cavitation has occurred. When the control system determines that cavitation occurs, in addition to the dynamic adjustment of the refrigeration system by the control system as described above, the control system can also adjust the rotating speed of the driving motor or the opening degree of the outlet valve of the low-temperature liquid pump 2 according to the need, reduce the conveying flow of the low-temperature fluid, and reduce the flow rate of the fluid, so as to inhibit the formation of cavitation bubbles.

[0025] The flow adjustment can work in cooperation with the refrigeration system as described above. For example, while reducing the flow, the control system still adjusts the cold energy output of the refrigeration system according to the temperature feedback of the low-temperature fluid, so as to ensure that the low-temperature fluid is always in a supercooled state, and further eliminate the cavitation inducement.

[0026] The flow sensor can be an existing electromagnetic flow meter, vortex flow meter, or other sensor that can achieve the flow monitoring in this embodiment.

[0027] Furthermore, the control system can also determine the cavitation state of the cryogenic liquid pump 2 by real-time detection of its vibration. Embodiments of the present invention also include a vibration sensor installed on the cryogenic fluid pump, which is connected to the control system. During normal operation of the cryogenic fluid pump, its vibration amplitude is within a specific stable range. The control system presets a threshold value for the vibration amplitude under normal operating conditions. Based on the piezoelectric or capacitive effect, when the pump body vibrates due to cavitation, the vibration sensor senses the vibration amplitude and converts it into an electrical signal output. The control system processes the electrical signal output by the vibration sensor. When the vibration amplitude detected by the vibration sensor exceeds this threshold, cavitation can be determined to have occurred. The vibration sensor can be an existing piezoelectric accelerometer, capacitive accelerometer, or other sensor capable of achieving vibration monitoring in this embodiment.

[0028] In addition to the flow sensor and vibration sensor described above for detecting the cavitation state of the cryogenic liquid pump 2, embodiments of the present invention also include multiple sensors for acquiring the pressure parameter P of the cryogenic fluid and the measured temperature T1 of the cryogenic liquid. These sensors are all connected to the control system and can transmit the acquired data to the control system. All of the above sensors can be implemented using existing sensors; this application does not improve the sensors, and therefore will not elaborate further.

[0029] Furthermore, the aforementioned control system incorporates a built-in storage module and a control module. The storage module stores saturation temperature-pressure relationship data for the cryogenic liquid and temperature-pressure diagram data indicating that cavitation does not occur in the cryogenic liquid pump 2. The control module can calculate the corresponding saturation temperature T2 based on the saturation temperature-pressure relationship data in the storage module and the acquired pressure parameter P. It also determines the required inlet temperature T3 for the cryogenic liquid pump 2 based on the stored temperature-pressure diagram data indicating that cavitation does not occur, while the actual measured temperature of the cryogenic fluid is T1. When cavitation occurs, the control system determines the operating power (speed) of the refrigeration system based on the flow rate of the cryogenic liquid pump 2, T3, and T1 to provide sufficient cooling energy to eliminate cavitation. This power (speed) - cooling energy is the built-in logic of the refrigeration system. When the temperature T4 provided by the refrigeration system is ≤ T3, the cryogenic fluid pump can start operation.

[0030] If cavitation occurs in the cryogenic fluid pump according to the control logic, the fluid delivery flow rate of the cryogenic fluid pump should be reduced, or the supply of cold energy to the refrigeration system should be increased, or the temperature range of the cold energy in the refrigeration system should be adjusted to eliminate or mitigate cavitation.

[0031] Further, the above refrigeration system is mainly composed of the compressor 5, the cooler 4, the multi-stream heat exchanger 3 and the expander 6, and each component is connected through a specific pipeline to form a complete circulation loop. The outlet of the compressor 5 is connected to the inlet of the cooler 4 through a pipeline with high pressure resistance, low temperature resistance and good sealing performance, so as to ensure that the compressed high-temperature refrigerant can smoothly enter the cooler 4 for cooling treatment. The outlet of the cooler 4 is connected to the first inlet of the multi-stream heat exchanger 3, so that the cooled refrigerant enters the multi-stream heat exchanger 3. The first outlet of the multi-stream heat exchanger 3 is connected to the inlet of the expander 6, so as to ensure that the cooled refrigerant can enter the expander 6 for expansion cooling operation. The outlet of the expander 6 is connected to the second inlet of the multi-stream heat exchanger 3, and the expanded and cooled refrigerant enters the multi-stream heat exchanger 3 again from here, and then flows out from the second outlet of the multi-stream heat exchanger 3 and returns to the inlet of the compressor 5, thereby forming a circulation of the refrigerant.

[0032] Further, the above compressor 5 can be a screw compressor 5, a piston compressor 5, and the compressor 5 is preferably a centrifugal impeller compressor 5. The above expander 6 is a centrifugal impeller expander 6. The centrifugal impeller compressor 5 and the centrifugal impeller expander 6 are coaxially arranged and driven by a driving device 7, and the driving device 7 can be a double-shaft motor which can simultaneously drive the compressor 5 and the expander 6 to operate.

[0033] When the low-temperature fluid is planned to be transmitted, the refrigeration system starts to operate first. The refrigerant compressed by the compressor 5 enters the cooler 4 for cooling, and then enters the multi-stream heat exchanger 3 for cooling, and then enters the expander 6 for expansion cooling. Then the refrigerant enters the multi-stream heat exchanger 3 again to exchange heat with the low-temperature fluid and returns to the inlet of the compressor 5.

[0034] The above is only a preferred embodiment of the present application, and does not limit the technical scope of the present application in any way. Any slight modification, equivalent change and modification made according to the technical essence of the present application to the above embodiment are still within the scope of the technical solution of the present application.

Claims

1. A cryogenic liquid pumpable transfer system having controllable cavitation, characterized by, The control system is connected with the cryogenic liquid pump, and the control system can receive the cavitation state of the cryogenic liquid pump in real time and dynamically control the fluid delivery flow of the cryogenic fluid pump according to the cavitation state of the cryogenic liquid pump. The control system is connected with the cryogenic liquid pump, and the control system can receive the cavitation state of the cryogenic liquid pump in real time and dynamically control the fluid delivery flow of the cryogenic fluid pump according to the cavitation state of the cryogenic liquid pump. The control system has a storage module and a control module, the storage module stores the saturation temperature-pressure relationship data of the cryogenic liquid and the temperature-pressure diagram data of the pump without cavitation; further comprising a plurality of sensors for obtaining the pressure parameter P of the cryogenic fluid and the measured temperature T1 of the cryogenic liquid; the control module can calculate the corresponding saturation temperature T2 from the obtained pressure parameter P according to the saturation temperature-pressure relationship data in the storage module, and determine the required inlet temperature T3 of the pump inlet according to the stored temperature-pressure diagram data of the pump without cavitation; when cavitation occurs, the control module implements at least one of the following control measures according to the measured temperature T1 of the cryogenic liquid, the flow of the refrigeration system and the determined required inlet temperature T3 of the pump inlet: reducing the fluid delivery flow of the cryogenic fluid pump, increasing the supply of cold energy of the refrigeration system, adjusting the temperature zone of the cold energy of the refrigeration system, thereby realizing the elimination or reduction of cavitation of the cryogenic liquid pump. The refrigeration system comprises a compressor, a cooler, a multi-stream heat exchanger and an expander; the outlet of the compressor is connected with the inlet of the cooler, the outlet of the cooler is connected with the first inlet of the multi-stream heat exchanger, the first outlet of the multi-stream heat exchanger corresponding to the first inlet is connected with the inlet of the expander, the outlet of the expander is connected with the second inlet of the multi-stream heat exchanger, the second outlet of the multi-stream heat exchanger corresponding to the second inlet is connected with the inlet of the compressor, and the multi-stream heat exchanger further comprises a third inlet and a third outlet; the third inlet is connected with the outlet of the cryogenic liquid source, and the third outlet is connected with the inlet of the cryogenic liquid pump.

2. The cryogenic liquid pumpable fluid delivery system of claim 1, wherein, Further comprising a flow sensor for detecting the inlet and outlet flow of the cryogenic fluid pump, the flow sensor being connected with the control system.

3. The cryogenic liquid pumpable fluid delivery system of claim 2, wherein, Further comprising a vibration sensor mounted on the cryogenic fluid pump, the vibration sensor being connected with the control system.

4. The cryogenic liquid pumpable fluid delivery system of claim 3, wherein, The cryogenic liquid source is a cryogenic liquid tank with cryogenic liquid stored inside.

5. The cryogenic liquid pumpable fluid delivery system of claim 4, wherein, The compressor is a centrifugal impeller compressor, and the expander is a centrifugal impeller expander or a cryogenic throttle valve.

6. The cryogenic liquid pumpable fluid delivery system of claim 5, wherein, Further comprising a driving device for driving the compressor and the expander to operate, one driving device being connected with the compressor and the expander, and the driving device can simultaneously drive the compressor and the expander to operate.

Images