Nitrogen preparation system and control method thereof

Abstract

The invention relates to the technical field of industrial equipment corrosion prevention, in particular to a nitrogen preparation system and a control method thereof.The nitrogen preparation system comprises a basic module group, a nitrogen storage unit and equipment to be protected, the basic module group comprises a nitrogen preparation unit, a gas storage unit and the equipment to be protected which are connected in sequence, and the nitrogen preparation unit prepares nitrogen through the pressure swing adsorption molecular sieve technology and outputs the nitrogen to the gas storage unit; the gas storage unit is connected with to-be-protected equipment through a main conveying pipeline; the nitrogen generation unit and the gas storage unit are respectively connected with the main control unit; and the expansion module group comprises a boosting storage module connected with the basic module group through a pipeline, and the boosting storage module is arranged between the gas storage unit and the to-be-protected equipment. In the application, a modular extensible framework is formed through the combined arrangement of the basic module group and the extension module group so as to adapt to different nitrogen yield and output pressure requirements, so that flexible extension is realized, and the linear extension capability of performing rust prevention on various equipment is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial equipment anti-corrosion, and in particular to a nitrogen preparation system and a control method thereof. Background Art

[0002] Metal corrosion is a common phenomenon in industrial production, leading not only to material degradation and equipment failure, but also to unexpected safety incidents. Nitrogen generation technology, as a highly effective protective measure, suppresses metal oxidative corrosion by filling confined spaces with high-purity nitrogen (≥99.9%), reducing oxygen concentration (typically <0.5%). However, existing nitrogen generation systems still suffer from technical deficiencies, such as insufficient flexibility to adapt to diverse operational needs. Summary of the Invention

[0003] In view of this, an object of the present invention is to provide a nitrogen preparation system and a control method thereof.

[0004] In a first aspect, an embodiment of the present invention provides a nitrogen production system, comprising:

[0005] The basic module group includes a nitrogen production unit, a gas storage unit and the equipment to be protected, which are connected in sequence. The nitrogen production unit uses pressure swing adsorption molecular sieve technology to prepare nitrogen and output it to the gas storage unit. The gas storage unit is connected to the equipment to be protected through a main transmission pipeline. The nitrogen production unit and the gas storage unit are also connected to the main control unit respectively.

[0006] The expansion module group includes a boost storage module connected to the basic module group through a pipeline, and the boost storage module is arranged between the gas storage unit and the equipment to be protected;

[0007] The intelligent control module group is in communication with the extension module group and the basic module group, and adjusts the gas production of the nitrogen production unit and the gas pressure in the main transmission pipeline by adjusting the operating parameters of the extension module group and the basic module group.

[0008] In combination with the first aspect, the boost storage module includes:

[0009] A supercharger, an input end of which is connected to the gas storage unit;

[0010] The medium-pressure storage tank is connected to the output end of the booster;

[0011] Constant pressure output main control unit, connected to the booster.

[0012] In combination with the first aspect, the extension module group further includes:

[0013] The air supply purification module is installed at the front end of the nitrogen production unit; the air supply purification module includes:

[0014] The air compressor unit has an air inlet connected to the outside air and an air outlet connected to the nitrogen production unit, and is used to compress the incoming air and output it to the nitrogen production unit;

[0015] The multi-stage filtration device includes a pre-filtration unit and a main filtration unit arranged in cascade; the pre-filtration unit is arranged at the air inlet end of the air compressor unit, and the main filtration unit includes a freeze dryer, an activated carbon adsorption tower and a precision filter connected in sequence along the air flow direction.

[0016] In combination with the first aspect, the extension module group further includes:

[0017] The monitoring module is provided in the basic module group; the monitoring module includes at least a gas purity analyzer, a pressure sensor, and a humidity detector.

[0018] In combination with the first aspect, the intelligent control module group includes:

[0019] A communication interface, connected to the main control unit via the communication interface;

[0020] The adaptive control algorithm module is connected to the communication interface, the monitoring module, the basic module group and the extension module group respectively.

[0021] In combination with the first aspect, the adaptive control algorithm module includes:

[0022] The working condition identification unit has an input end connected to the monitoring module and an output end connected to the fuzzy PID controller; it is used to obtain the nitrogen purity data, pressure data and humidity data collected by the monitoring module to identify the current working condition;

[0023] The fuzzy PID controller has an input end connected to the operating condition identification unit and an output end connected to the basic module group and the extended module group, and is used to adjust the operating parameters of the basic module group and the extended module group based on the current operating conditions.

[0024] In combination with the first aspect, the intelligent control module group further includes: a predictive maintenance unit, the input end of the predictive maintenance unit is connected to the monitoring module, and the output end is connected to the fuzzy PID controller.

[0025] In combination with the first aspect, it also includes a warning module, which is communicatively connected to the fuzzy PID controller.

[0026] In a second aspect, the present invention further provides a control method for a nitrogen production system, which is applied to the intelligent control module group in the nitrogen production system as described above; the method comprises:

[0027] Obtain historical gas consumption data of the equipment to be protected within the first period;

[0028] Input the historical gas consumption data within the first time period into the pre-trained prediction model, and output the predicted gas consumption data within the second time period;

[0029] Adjusting the operating parameters of the nitrogen preparation system based on the predicted gas consumption data within the second period;

[0030] Among them, the prediction model is an LSTM neural network with 3 hidden layers.

[0031] In combination with the second aspect, the boost storage module includes a supercharger; the expansion module group further includes an air supply purification module and an alarm module, and the air supply purification module includes an air compressor group;

[0032] The method also includes:

[0033] Obtain the vibration spectrum of the air compressor unit and the three-phase current of the supercharger;

[0034] Wavelet packet decomposition is performed on the vibration spectrum to extract the energy proportion of the 2-4kHz frequency band as the wear characteristic. At the same time, FFT analysis is performed on the three-phase current to calculate the ratio of the fundamental wave to the preset harmonic current as the bearing health indicator;

[0035] When the wear characteristic value is greater than the characteristic value threshold, and / or the bearing health index is less than the preset index threshold, the warning module is controlled to operate.

[0036] The embodiments of the present invention bring the following beneficial effects: the nitrogen preparation system and control method provided by the present application, the nitrogen preparation system comprising: a basic module group, comprising a nitrogen production unit, a gas storage unit and equipment to be protected connected in sequence, the nitrogen production unit adopts pressure swing adsorption molecular sieve technology to prepare nitrogen and output it to the gas storage unit, the gas storage unit is connected to the equipment to be protected through a main transmission pipeline; the nitrogen production unit and the gas storage unit are also respectively connected to the main control unit; an extension module group, comprising a boost storage module connected to the basic module group pipeline, the boost storage module is arranged between the gas storage unit and the equipment to be protected; an intelligent control module group, which is communicatively connected to the extension module group and the basic module group, and adjusts the gas production of the nitrogen production unit and the gas pressure in the main transmission pipeline by adjusting the operating parameters of the extension module group and the basic module group.

[0037] In this application, a modular and scalable architecture is formed by combining a basic module group and an expansion module group to adapt to different nitrogen production and output pressure requirements, thereby achieving flexible expansion and improving the linear expansion capability of anti-corrosion for various types of equipment.

[0038] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purposes and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 A schematic structural diagram of a nitrogen production system provided in an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of signal transmission in a nitrogen production system provided in an embodiment of the present invention;

[0043] Figure 3 A flow chart of a control method for a nitrogen production system provided in an embodiment of the present invention;

[0044] Figure 4 A flow chart of a control method for another nitrogen production system provided in an embodiment of the present invention.

[0045] Reference numerals:

[0046] 1-Nitrogen production unit, 2-Gas storage unit, 3-Main control unit, 4-Equipment to be protected, 5-Gas supply purification module, 6-Boost storage module, 7-Monitoring module, 8-Intelligent control module group. DETAILED DESCRIPTION

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0048] To facilitate understanding of this embodiment, the following is a brief introduction to the technical terms used in this application.

[0049] Nitrogen generation technology utilizes the inert properties of nitrogen (N) to protect equipment and materials from oxidation, corrosion, moisture, and microbial damage. Nitrogen is chemically stable and does not readily react with other substances, making it widely used in industries such as industry, electronics, food, and medicine.

[0050] After introducing the technical terms involved in this application, the application scenarios and design concepts of the embodiments of this application are briefly introduced.

[0051] The existing nitrogen preparation system still has the technical defect of being insufficiently flexible to adapt to different work requirements.

[0052] Based on this, an embodiment of the present application provides a nitrogen preparation system and a control method thereof.

[0053] Example 1

[0054] This application provides a nitrogen preparation system, combined with Figure 1 、 Figure 2 As shown, the system includes: a basic module group, an extension module group and an intelligent control module group 8.

[0055] The basic module group includes a nitrogen production unit 1, a gas storage unit 2 and a device to be protected 4 connected in sequence. The nitrogen production unit 1 uses pressure swing adsorption molecular sieve technology to prepare nitrogen and output it to the gas storage unit 2. The gas storage unit 2 is connected to the device to be protected 4 through a main transmission pipeline; the nitrogen production unit 1 and the gas storage unit 2 are also respectively connected to the main control unit 3.

[0056] The expansion module group includes a boost storage module 6 connected to the basic module group through a pipeline. The boost storage module 6 is arranged between the gas storage unit 2 and the equipment to be protected 4.

[0057] The intelligent control module group 8 is in communication with the expansion module group and the basic module group, and adjusts the gas production of the nitrogen production unit 1 and the gas pressure in the main transmission pipeline by adjusting the operating parameters of the expansion module group and the basic module group.

[0058] In this application, a modular and scalable architecture is formed by combining a basic module group and an expansion module group to adapt to different nitrogen production and output pressure requirements, thereby achieving flexible expansion and improving the linear expansion capability of anti-corrosion for various types of equipment.

[0059] The nitrogen production unit 1 is used to separate gases based on the pressure swing adsorption (PSA) technology by selectively adsorbing oxygen (O) and nitrogen (N) in the air through the molecular sieve in the adsorption tower. Specifically, the carbon molecular sieve first preferentially adsorbs O (kinetic diameter ), basic separation is achieved at 0.6-0.8MPa, and the purity of nitrogen obtained by single-stage adsorption is 95%-99%; then, the nitrogen is separated by 13X molecular sieve CO The nitrogen purity obtained by the two-stage series purification is 99%-99.9%. Subsequently, the nitrogen is purified again by lithium ion enhancement through Li-LSX molecular sieve to enhance the O selectivity. Based on the above three-stage series purification, the ultra-pure nitrogen purity is 99.9%-99.99%.

[0060] The nitrogen production unit 1 includes a basic tower group and an extended tower group. The basic tower group includes three adsorption towers, two of which are used for adsorption and one for regeneration. The gas production capacity of a single adsorption tower is A (for example, A = 5Nm 3 / h), combined with the above example, the gas production when two adsorption towers work simultaneously should be 50Nm 3 / h, by adding a throttle valve, the output of the single adsorption tower can be limited to the production flow (for example, when the opening of the throttle valve is 10%, the production flow of the single adsorption tower is 2Nm 3 / h). Each extended tower group includes 2 additional towers. By adjusting the number of additional towers, the gas production can be adjusted between 1-2500Nm 3 / h.

[0061] In this embodiment, a dual-mode operation mechanism is employed, including continuous and intermittent operation. Continuous operation involves uninterrupted operation for 24 hours, with each adsorption tower operating in a cycle of "adsorption-pressure equalization-regeneration-standby." Program-controlled valves achieve seamless switching, ensuring that at least two adsorption towers operate simultaneously to ensure continuous airflow. Intermittent operation involves switching individual adsorption towers on and off based on the comparison between specific indicators and indicator thresholds. In this embodiment, the adsorption towers are equipped with an automatic regeneration program, with the regeneration cycle negatively correlated with the gas purity. Specifically, the regeneration cycle is shortened when the nitrogen purity reaches the upper limit and extended when the purity reaches the lower limit.

[0062] Gas storage unit 2 includes a low-pressure storage tank with a vertical double-layer vacuum insulation structure, a pressure ≤ 1.0 MPa and a volume of 1-100m 3 , tank wall thickness δ = PD ÷ (2S × E-0.2P), where P is pressure, D is the inner diameter of the low-pressure storage tank, S is the material yield strength, and E is the welding joint coefficient.

[0063] The gas storage unit 2 also includes a buffer pressure stabilizing device, which is equipped with a pressure compensator and an emergency pressure relief valve; when the set opening pressure of the emergency pressure relief valve is reached, the emergency pressure relief valve opens to relieve pressure to avoid excessive pressure in the gas storage unit 2.

[0064] In conjunction with the first aspect, the boost storage module includes: a booster, a medium-pressure storage tank, and a constant-pressure output main control unit (not shown in the figure).

[0065] The input end of the supercharger is connected to the gas storage unit 2 .

[0066] The medium-pressure storage tank is connected to the output end of the booster.

[0067] Constant pressure output main control unit, connected to the booster.

[0068] The boost storage module 6 includes a booster and a medium-pressure storage tank connected in sequence, which are not shown in the figure.

[0069] Among them, the supercharger includes a tubular interstage cooler and a stainless steel bellows pulsation damper; nitrogen is introduced into the tube side of the tubular interstage cooler and circulating cooling water is introduced into the shell side, and a water flow control valve with temperature feedback regulation is configured; the effective volume of the stainless steel bellows pulsation damper is 1.2-1.8 times the single-stroke displacement of the supercharger, and the damping coefficient is ≥0.75.

[0070] The medium pressure storage tank is connected to the output end of the booster and is used to store pressurized nitrogen. The tank body of the medium pressure storage tank is equipped with a pressure transmitter and a spring-loaded safety valve. The tank body is made of alloy steel. The pressure of the medium pressure storage tank is 2.0-4.0MPa and the volume is 1-40m 3 The high-pressure storage tank is equipped with a shell and tube interstage cooler and a stainless steel bellows pulsation damper. The cooling medium is circulating water to reduce the temperature and pulsation during the pressurization process.

[0071] The constant pressure output main control unit includes a variable frequency drive motor, a PID controller, and a frequency converter; the input end of the PID controller is connected to the pressure sensor at the outlet of the gas storage unit 2, and the output end is connected to the frequency converter of the variable frequency drive motor to control the variable frequency drive motor to output the variable frequency driving force to drive the booster to operate at variable frequency, maintaining the pressure of the output nitrogen within the preset pressure range.

[0072] In combination with the first aspect, the expansion module group further includes: an air supply purification module 5, which is arranged at the air inlet front end of the nitrogen production unit 1. The air supply purification module 5 includes an air compressor unit and a multi-stage filtering device.

[0073] The air inlet of the air compressor unit is connected to the outside air, and the air outlet is connected to the nitrogen production unit 1, so as to compress the air and output it to the nitrogen production unit 1;

[0074] The multi-stage filtration device includes a pre-filtration unit and a main filtration unit arranged in cascade; the pre-filtration unit is arranged at the air inlet end of the air compressor unit, and the main filtration unit includes a freeze dryer, an activated carbon adsorption tower and a precision filter connected in sequence along the air flow direction.

[0075] In this embodiment, by adding an air supply purification module 5, the air flow entering the nitrogen production unit 1 is compressed and multi-stage filtered. The filtration accuracy of the pre-filter is 3μm, which is used to filter out particles larger than 3μm in the air flow; in this embodiment, the pre-filter unit is composed of a glass fiber filter element, and the filter element is arranged at an angle of 15-30 degrees to the air flow direction. Preferably, the glass fiber filter element of the pre-filter unit adopts a Z-shaped pleated structure with a pleat density of 8-12 pleats / cm. The main filter unit adopts a three-stage filtration architecture, including a freeze dryer, an activated carbon adsorption tower and a precision filter connected in series in the direction of air flow. The precision filter adopts a gradient filtration structure, including a 1μm polypropylene primary filter element, a 0.1μm glass fiber medium-efficiency filter element, and a 0.01μm polytetrafluoroethylene (PTFE) terminal filter element.

[0076] In combination with the first aspect, the extension module group further includes: a monitoring module 7 .

[0077] The monitoring module 7 is provided in the basic module group; the monitoring module 7 includes at least a gas purity analyzer, a pressure sensor, and a humidity detector.

[0078] As will be appreciated, a gas purity analyzer is located within nitrogen generation unit 1 to monitor the purity of the generated nitrogen; a pressure sensor is located within nitrogen generation unit 1 and gas storage unit 2 to monitor the gas flow pressure; and a humidity detector is located within nitrogen generation unit 1 and gas storage unit 2 to monitor the gas flow humidity. In this embodiment, the gas purity analyzer has a range of 78%-99.999%; the pressure sensor has a range of 0-1.5 MPa; and the humidity detector has a relative humidity range of 0%-100% RH, with an accuracy of ±2% to ±5% RH.

[0079] In combination with the first aspect, the intelligent control module group 8 includes a communication interface and an adaptive control algorithm module.

[0080] The intelligent control module group 8 includes a communication interface for communicating with an external main control unit to synchronize the control parameters of the adaptive control algorithm module to the main control unit in real time. The main control unit sends control instructions to the adaptive control algorithm module to achieve remote operation adjustment.

[0081] In this embodiment, the main control unit utilizes a triple-redundant (TMR) architecture. Key control modules within the main control unit (e.g., CPU, communication module) operate in parallel using three independent hardware systems. Each module performs the same task, and the output is compared using a "majority voter." If a module fails, the system automatically adopts the same output from the remaining two modules, ensuring continuous operation.

[0082] In the present embodiment, the control cycle of the main control unit can be adjusted in the range of 50-500ms, wherein the control cycle is the complete cycle time for the system to complete a data acquisition, logical operation, and output control. The specific control cycle is adjusted according to the size of the system composed of the number of applications of the expansion module. In this way, the cycle can be automatically optimized according to the real-time load, balancing the response speed and resource occupancy. At the same time, the intelligent instrument interface of the HART7 protocol is supported, and the intelligent instruments such as pressure, temperature, flow that conform to the HART7 protocol are compatible. It has a hierarchical authority management module, supports operator-level, engineer-level, and administrator-level three-level authority, and the operation tracing database adopts SQL Server database, records operation logs and alarm information for no less than one year, and can be expanded to a system capacity of 5000 I / O points to meet the control requirements of large-scale nitrogen preparation systems.

[0083] In combination with the first aspect, the adaptive control algorithm module includes a fuzzy PID controller and an operating condition identification unit.

[0084] The input end of the working condition identification unit is connected to the monitoring module 7, and the output end is connected to the fuzzy PID controller; it is used to obtain the nitrogen purity data, pressure data and humidity data collected by the monitoring module 7 to identify the current working condition.

[0085] The input end of the fuzzy PID controller is connected to the working condition identification unit, and the output end is connected to the basic module group and the extended module group, and is used to adjust the operating parameters of the basic module group and the extended module group based on the current working condition.

[0086] It can be understood that the present application collects monitoring data through the monitoring module 7 connection, and inputs the collected detection data into the working condition identification unit for working condition identification. The fuzzy PID controller performs control operations based on the obtained working condition identification results to control the basic module group and the extended module group to adjust the operating parameters, thereby realizing adaptive adjustment according to different working conditions and improving the degree of automation.

[0087] In this embodiment, the fuzzy PID controller adopts fuzzy rules based on expert experience, and the membership function selects Gaussian function. The operating condition identification unit receives the nitrogen purity, pressure, and humidity data from the monitoring module 7 in real time, judges the system operating condition by setting thresholds and trend analysis, and dynamically adjusts the molecular sieve regeneration cycle of the nitrogen production unit 1 and / or the variable frequency drive parameters of the boost module 6. For example, when the nitrogen purity decreases, the regeneration cycle is shortened; when the gas tank pressure is too high, the booster speed is reduced.

[0088] In combination with the first aspect, the intelligent control module group 8 further includes: a predictive maintenance unit, the input end of the predictive maintenance unit is connected to the monitoring module 7, and the output end is connected to the fuzzy PID controller.

[0089] In this embodiment, the predictive maintenance unit incorporates a support vector machine (SVM)-based equipment health assessment model. The vibration spectrum of the air compressor group and the nitrogen booster detected by monitoring module 7 are fed into the model, which then outputs detection results and a warning level classification based on these detection results. The output results are then fed into a fuzzy PID controller to adjust the operating parameters of the basic and extended module groups.

[0090] In combination with the first aspect, the system further includes an alarm module, which is communicatively connected to the fuzzy PID controller.

[0091] It is understood that when the output detection results of the equipment health assessment model indicate equipment abnormality, the fuzzy PID controller controls the operation of the warning module to remind operation and maintenance personnel to promptly perform equipment maintenance, system adjustments, and operational optimization through specific warning modes. It is understood that the warning module can be a multimodal warning unit, configured to trigger different forms of warning signals based on the comprehensive risk index R value, including at least two forms of audible and visual alarms, mechanical indications, digital communications, and environmental linkage, and present different degrees of warning effects depending on the warning level. This is not detailed here.

[0092] In this embodiment, the intelligent control module group 8 also includes: a multi-protocol communication gateway that supports parallel communication of OPC UA, Modbus TCP, and MQTT protocols, and is equipped with a data encryption module and a breakpoint resume module.

[0093] The intelligent control module group 8 also includes: an edge computing node, which is configured with a nitrogen consumption prediction model and a tank pressure optimization model. The nitrogen consumption prediction model establishes an LSTM neural network based on the historical gas consumption data of the equipment to be protected 4 to predict the gas consumption in the next 24 hours, and drives the nitrogen production unit 1 to start the preparation process in advance.

[0094] In the second aspect, the present application provides a control method for a nitrogen preparation system, which is applied to the intelligent control module group 8 in the above-mentioned nitrogen preparation system. Figure 3 As shown, the method includes:

[0095] S110: Obtain historical gas usage data of the equipment to be protected within a first period of time.

[0096] S120: Input the historical gas usage data within the first time period into a pre-trained prediction model, and output the predicted gas usage data within the second time period.

[0097] S130: Adjust operating parameters of the nitrogen preparation system based on the predicted gas usage data within the second time period.

[0098] Among them, the prediction model is an LSTM neural network with 3 hidden layers.

[0099] In this embodiment, historical gas consumption data is obtained, and future gas consumption is predicted based on the historical gas consumption data based on the data processing capability of the prediction model, and then the operating parameters are adjusted to regulate the system according to the gas demand so that the gas production can meet the gas demand.

[0100] The first duration should be shorter than the second duration to ensure sufficient gas production. In this embodiment, the first duration is set to 20 hours and the second duration is set to 24 hours.

[0101] As an example, a preset communication protocol is used to obtain 72 hours of historical gas usage data from the flow meter of device 4 to be protected. The data sampling interval is set to a set value to obtain time-series data for gas usage, generating an input sequence. This data is then cleaned for abnormalities. The cleaned historical data is then fed into an LSTM prediction model. As an example, the LSTM prediction model consists of an input layer, a hidden layer, and an output layer. The input layer consists of 24 neurons for receiving time-series data. The hidden layer has three layers, each containing multiple LSTM units with residual connections between layers. The output layer consists of 24 neurons, outputting the predicted gas usage for the next 24 hours. The model is trained using the Adam optimizer and the Huber loss function. The training dataset contains 2000 sets of data covering four seasons, with a prediction error of ≤±5%.

[0102] In combination with the first aspect, the boost storage module 6 includes a supercharger; the expansion module group further includes an air supply purification module 5 and an alarm module, and the air supply purification module 5 includes an air compressor group.

[0103] Combine Figure 4 As shown, the method further includes:

[0104] S210: Obtain a vibration spectrum of the air compressor unit and a three-phase current of the supercharger.

[0105] S210, performing wavelet packet decomposition on the vibration spectrum to extract the energy proportion of the 2-4kHz frequency band as the wear characteristic. At the same time, performing FFT analysis on the three-phase current to calculate the ratio of the fundamental wave to the preset harmonic current as the bearing health indicator.

[0106] S230: When the wear characteristic value is greater than the characteristic value threshold, and / or the bearing health index is less than the preset index threshold, the warning module is controlled to operate.

[0107] In this embodiment, the wear characteristic quantity and bearing health index are obtained by acquiring and processing the vibration spectrum of the gas compressor unit and the three-phase current of the supercharger. Subsequently, fault detection is performed based on the dual-threshold judgment logic to provide timely warnings when a fault occurs.

[0108] Specifically, an accelerometer (sampling rate ≥ 10kHz) installed on the bearing housing of the air compressor unit collects vibration signals in real time. Wavelet packet decomposition (WPD) is used to divide the signals into frequency bands, extracting the energy percentage in the 2-4kHz band to reflect high-frequency impact characteristics such as bearing fatigue cracks and ball spalling. For example, under normal conditions, the energy percentage in the 2-4kHz band is less than 10%. When bearings are worn, the energy in this frequency band rises significantly to 15%-30%.

[0109] Perform a Fast Fourier Transform (FFT) on the three-phase current of the supercharger drive motor to calculate the ratio of the fundamental to third harmonic currents. This ratio can indicate faults such as aging of the motor winding insulation and rotor eccentricity. For example, in a healthy state, the ratio is greater than 1.0. When bearing wear causes rotor vibration, the increase in the third harmonic reduces the ratio to 0.5-0.8.

[0110] As a preference, multiple feature thresholds and multiple indicator thresholds may be further combined to set different warning levels and execute different warning modes. This may be set according to actual conditions and will not be elaborated here.

[0111] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems and devices can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0112] In addition, in the description of the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0113] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0114] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0115] Finally, it should be noted that the above embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above embodiments within the technical scope disclosed by the present invention, or replace some of the technical features therein with equivalents. Such modifications, changes or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A nitrogen preparation system, characterized in that: include: A basic module group comprises a nitrogen production unit (1), a gas storage unit (2) and a device to be protected (4) connected in sequence, wherein the nitrogen production unit (1) uses a pressure swing adsorption molecular sieve technology to prepare nitrogen and outputs it to the gas storage unit (2), and the gas storage unit (2) is connected to the device to be protected (4) via a main transmission pipeline; the nitrogen production unit (1) and the gas storage unit (2) are also respectively connected to a main control unit (3); An expansion module group, comprising a boost storage module (6) connected to the basic module group through a pipeline, wherein the boost storage module (6) is arranged between the gas storage unit (2) and the equipment to be protected (4); An intelligent control module group (8) is communicatively connected with the expansion module group and the basic module group, and adjusts the gas production of the nitrogen production unit (1) and the gas pressure in the main delivery pipeline by adjusting the operating parameters of the expansion module group and the basic module group.

2. The system according to claim 1, wherein: The boost storage module (6) comprises: A supercharger, the input end of which is connected to the gas storage unit (2); a medium-pressure storage tank connected to the output end of the booster; A constant pressure output main control unit is connected to the booster.

3. The system according to claim 1, wherein: The extension module group further includes: An air supply purification module (5) is arranged at the air inlet front end of the nitrogen production unit (1); the air supply purification module (5) comprises: An air compressor unit, the air inlet of which is connected to the outside air and the air outlet of which is connected to the nitrogen generator unit (1), is used to compress the air introduced therein and output it to the nitrogen generator unit (1); The multi-stage filtering device includes a pre-filter unit and a main filter unit arranged in cascade; the pre-filter unit is arranged at the air inlet end of the air compressor unit, and the main filter unit includes a freeze dryer, an activated carbon adsorption tower and a precision filter connected in sequence along the air flow direction.

4. The system according to claim 1, wherein: The extension module group further includes: A monitoring module (7) is provided in the basic module group; the monitoring module at least includes a gas purity analyzer, a pressure sensor, and a humidity detector.

5. The system according to claim 4, characterized in that The intelligent control module group (8) includes: A communication interface, connected to a main control unit (3) via the communication interface; The adaptive control algorithm module is connected to the communication interface, the monitoring module, the basic module group and the expansion module group respectively.

6. The system according to claim 5, characterized in that The adaptive control algorithm module includes: A working condition identification unit, the input end of which is connected to the monitoring module (7) and the output end of which is connected to the fuzzy PID controller; and used for obtaining nitrogen purity data, pressure data, and humidity data collected by the monitoring module (7) to identify the current working condition; A fuzzy PID controller, whose input end is connected to the operating condition identification unit and whose output end is connected to the basic module group and the extended module group, is used to adjust the operating parameters of the basic module group and the extended module group based on the current operating condition.

7. The system according to claim 1, wherein: The intelligent control module group (8) further comprises a predictive maintenance unit, wherein the input end of the predictive maintenance unit is connected to the monitoring module (7), and the output end is connected to the fuzzy PID controller.

8. The system according to claim 7, characterized in that It also includes an alarm module, which is communicatively connected with the fuzzy PID controller.

9. A control method for a nitrogen production system, characterized in that: The method is applied to the intelligent control module group (8) in the nitrogen preparation system according to any one of claims 1 to 8; the method comprises: Obtain historical gas consumption data of the equipment to be protected within a first period of time; Inputting the historical gas usage data within the first time period into a pre-trained prediction model, and outputting predicted gas usage data within the second time period; adjusting operating parameters of the nitrogen production system based on the predicted gas usage data within the second time period; The prediction model is an LSTM neural network with three hidden layers.

10. The control method according to claim 9, characterized in that: The boost storage module (6) includes a supercharger; the expansion module group further includes an air supply purification module (5) and a warning module, and the air supply purification module (5) includes an air compressor group; The method further comprises: Obtaining a vibration spectrum of the air compressor unit and a three-phase current of the supercharger; Performing wavelet packet decomposition on the vibration spectrum to extract the energy proportion of the 2-4kHz frequency band as a wear characteristic. At the same time, performing FFT analysis on the three-phase current to calculate the ratio of the fundamental wave to the preset harmonic current as a bearing health indicator. When the wear characteristic value is greater than the characteristic value threshold, and / or the bearing health index is less than a preset index threshold, the warning module is controlled to operate.

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