Real-time monitoring method and system for fatigue life of heat accumulator

Abstract

The invention discloses a real-time monitoring method and system for fatigue life of a heat accumulator. The method and system are suitable for a steam heat accumulation pressure container under variable-temperature and variable-pressure operation conditions. Pressure and temperature sensors are arranged on a heat accumulator, operation data are collected in real time, and in combination with a fatigue cycle recognition algorithm, the change amplitude of pressure and temperature is judged and recognized according to pressure vessel analysis standards such as JB4732 / GB4732 and the like, and the number of fatigue cycles is accumulated. Meanwhile, the theoretical total fatigue life of the heat accumulator is calculated based on a finite element analysis method, and the remaining life of the heat accumulator is evaluated in real time through the difference value mode between the theoretical total fatigue life and the accumulated fatigue cycle number. The system has the functions of remote monitoring, alarming, data visualization and the like, and can meet the dynamic monitoring requirements under the parallel connection of a plurality of heat accumulators or the complex steam use working condition. According to the invention, the safety management level of the fatigue container is improved, and technical support is provided for scientific maintenance and operation scheduling of the pressure container.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure vessel safety monitoring, and in particular to a real-time monitoring method and system for fatigue life of a variable temperature and pressure heat accumulator, which is specifically applicable to steam heat accumulators used in the oxygen blowing process of converters in the steel and metallurgical industry. Background Art

[0002] In the iron and steel industry, the oxygen blowing process in converters generates large amounts of high-temperature flue gas. This high-temperature flue gas, after passing through a waste heat boiler (HRSG), generates high-pressure steam. To effectively utilize this waste heat steam and ensure a stable steam supply to users, a steam accumulator is often installed. This steam accumulator stores and releases thermal energy through a process of charging (steam intake) and releasing (steam output).

[0003] Typically, during the regenerator charging process, the pressure increases from 1.3MPa to 3.2MPa, and the temperature rises from 191°C to 237°C. During the discharge process, the pressure drops from 3.2MPa to 1.3MPa, and the temperature drops from 237°C to 191°C. This type of equipment exhibits significant cyclical pressure and temperature fluctuations during use, and is classified as a "fatigue vessel" under the JB4732 / GB4732 standards. Fatigue strength assessments and cycle monitoring are required to ensure safe operation during its service life.

[0004] Under ideal operating conditions, if a converter is equipped with a regenerator, and the regenerator's heat charging and discharging process is completely synchronized with the converter's oxygen blowing, then the number of fatigue cycles can be directly deduced from the converter's smelting times. Figures 1 to 3 As shown in the figure, the following complex working conditions often exist in the actual production process: 1. Multiple converters 1 share one heat accumulator 2; 2. Multiple converters 1 correspond to multiple regenerators 2; 3. The steam consumption on the steam user side fluctuates greatly, resulting in incomplete charging and discharging processes of the heat accumulator, and the heat may be charged before the heat release is completed.

[0005] These complex working conditions make it impossible to accurately record the number of fatigue cycles of the heat accumulator during actual operation, and the remaining life of the container cannot be accurately obtained. It can only be blindly calculated according to the service life marked on the design drawings (because other complex working conditions cannot predict the number of charging and discharging times per unit time, the number of cycles marked in the design report are all estimated one-to-one according to the converter heat accumulator). It is impossible to accurately judge the remaining life of the container, and the real-time status of the heat accumulator during its life cycle is not fully understood. The service life of the heat accumulator is greater than 15 years, so there are still safety hazards in long-term operation. Summary of the Invention

[0006] The embodiments of the present invention provide a method and system for real-time monitoring of fatigue life of a heat accumulator, which can accurately determine the remaining life of the container and grasp the real-time status of the heat accumulator during its life cycle.

[0007] In a first aspect, the present invention provides a method for real-time monitoring of fatigue life of a heat accumulator, comprising: Real-time collection of pressure and temperature data of heat accumulator; Determine the change range of pressure and temperature data according to the standard, identify and accumulate the number of fatigue cycles; The theoretical total fatigue life of the heat accumulator is calculated based on the finite element analysis method, and the remaining life is evaluated in real time by the difference between the theoretical total fatigue life and the accumulated number of fatigue cycles.

[0008] In some instances, the real-time collected pressure data and temperature data are transmitted to a server via a PLC, and a historical database containing timestamps, pressure values, and temperature values ​​is established via the server.

[0009] In some examples, judging the magnitude of changes in pressure data and temperature data according to the standard, and identifying and accumulating the number of fatigue cycles, includes: Refer to the relevant provisions of other standards such as JB4732 or GB4732, the pressure vessel analysis and design standard, to establish a fatigue cycle identification strategy, and identify and accumulate the number of fatigue cycles according to the fatigue cycle identification strategy.

[0010] In some examples, the calculating of the theoretical total fatigue life of the heat accumulator based on a finite element analysis method includes: A three-dimensional structural model of the heat accumulator was established, and typical operating pressure and temperature changes were applied to the three-dimensional structural model based on thermal-mechanical coupling boundary conditions. The stress-strain response curve at the dangerous section is obtained, and the theoretical total fatigue life of the heat accumulator is evaluated using the SN curve and Miner damage accumulation theory.

[0011] In some examples, the method further comprises: The operating parameters and fatigue status of the heat accumulator are displayed in real time through the industrial SCADA system or Web visualization platform, and alarm push is supported.

[0012] In a second aspect, the present invention provides a real-time monitoring system for fatigue life of a heat accumulator, comprising: Data acquisition module, used to collect real-time pressure and temperature data of the heat accumulator; Real-time fatigue recognition module, used to judge the change amplitude of pressure data and temperature data according to standards, identify and accumulate the number of fatigue cycles; A simulation module for calculating the theoretical total fatigue life of the heat accumulator based on the finite element analysis method; The evaluation module is used to evaluate the remaining life in real time by the difference between the theoretical total fatigue life and the accumulated number of fatigue cycles.

[0013] In some instances, the real-time collected pressure data and temperature data are transmitted to a server via a PLC, and a historical database containing timestamps, pressure values, and temperature values ​​is established via the server.

[0014] In some examples, the real-time fatigue identification module is used to establish a fatigue cycle identification strategy with reference to relevant provisions in other standards such as the pressure vessel analysis and design standard JB4732 or GB4732, and to identify and accumulate the number of fatigue cycles according to the fatigue cycle identification strategy.

[0015] In some instances, the simulation module is used to establish a three-dimensional structural model of the heat accumulator, apply typical operating pressure and temperature changes in the three-dimensional structural model according to thermal-mechanical coupling boundary conditions; obtain the stress-strain response curve at the dangerous section, and use the SN curve and Miner damage accumulation theory to evaluate the theoretical total fatigue life of the heat accumulator.

[0016] In some examples, the system further comprises: The display module is used to display the operating parameters and fatigue status of the heat accumulator in real time through the industrial SCADA system or Web visualization platform, and supports alarm push.

[0017] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art: The present invention collects heat accumulator temperature and pressure data online, uses finite element software to analyze the total fatigue cycle life of the heat accumulator, and uses the collected cumulative data to calculate the number of cycles completed, thereby accurately grasping the remaining service life of the heat accumulator, keeping track of the heat accumulator's fatigue status at all times, improving its operational safety during its service life, and also providing a basis for extending the use of the heat accumulator after it reaches its designed service life (for example, after the heat accumulator reaches its designed service life, if there are still many cycles remaining, the service life of the heat accumulator can be extended in accordance with relevant national regulations after relevant inspections by the pressure vessel management department). BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 This is a schematic diagram of a one-to-one connection between a converter and a heat accumulator provided in an embodiment of the present invention; Figure 2This is a schematic diagram of the connection between two converters and one heat accumulator provided by an embodiment of the present invention; Figure 3 This is a schematic diagram of the connection between three converters and two regenerators provided in an embodiment of the present invention; Figure 4 is a schematic diagram of a method provided by an embodiment of the present invention; Figure 5 Schematic diagram of the system structure provided by an embodiment of the present invention; In the figure, 1. converter, 2. regenerator. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0021] In the following description, specific embodiments of the present invention will be described with reference to steps and symbols performed by one or more computers, unless otherwise specified. Therefore, these steps and operations will be mentioned several times as being performed by a computer, and computer execution as referred to herein includes operations by a computer processing unit that represents electronic signals of data in a structured form. This operation converts the data or maintains it at a location in the computer's memory system, which can be reconfigured or otherwise change the operation of the computer in a manner familiar to testers in the field. The data structure in which the data is maintained is a physical location in the memory, which has specific characteristics defined by the data format. However, the principles of the present invention are described in the above text, which does not represent a limitation, and testers in the field will understand that the various steps and operations below can also be implemented in hardware.

[0022] As used herein, the terms "module" or "unit" may be considered software objects executed on the computing system. The various components, modules, engines, and services herein may be considered implementation objects on the computing system. While the devices and methods herein are preferably implemented in software, they may also be implemented in hardware and remain within the scope of protection of the present invention.

[0023] It will be understood by those skilled in the art that, unless expressly stated otherwise, the singular forms "a", "an", and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, "connected" or "coupled" as used herein may include wireless connections or wireless couplings. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0024] In a first embodiment of the present invention, a method for real-time monitoring of fatigue life of a heat accumulator is provided, such as Figure 4 As shown, the following steps are included: S1: Real-time collection of pressure and temperature data of the heat accumulator; S2: Determine the change range of pressure data and temperature data according to the standard, identify and accumulate the number of fatigue cycles; S3: Calculate the theoretical total fatigue life of the heat accumulator based on the finite element analysis method; S4: Real-time evaluation of the remaining life by the difference between the theoretical total fatigue life and the accumulated number of fatigue cycles.

[0025] In step S1, a plurality of pressure sensors and temperature sensors are installed on the heat accumulator to collect the operating parameters inside the container in real time.

[0026] In the data collection and storage of step S1, the sensor data is collected in real time through the PLC and transmitted to the server to establish a historical database containing timestamps, pressure values, and temperature values.

[0027] In the data processing and fatigue cycle identification algorithm of step S2, a fatigue cycle identification strategy is established by referring to the relevant provisions of the pressure vessel analysis and design standard JB4732 or other standards.

[0028] For example: - If the pressure variation between two adjacent recording points exceeds 20% of the design pressure, it is determined to be a fatigue cycle; - If the temperature variation between two adjacent recording points exceeds 26~50℃, it is determined to be a fatigue cycle; - If the temperature variation between two adjacent recording points exceeds 51~100℃, it is determined to be two fatigue cycles; … In the calculation of the theoretical fatigue life of the heat accumulator in step S3, fatigue life assessment is performed based on the fatigue design specifications in standards such as "Steel Pressure Vessels" (GB150) and "Analysis and Design of Pressure Vessels" (JB4732), combined with finite element analysis software (such as ANSYS, ABAQUS, etc.): - Establish a three-dimensional structural model of the heat storage tank; - Apply typical working pressure and temperature changes according to thermal-mechanical coupling boundary conditions; - Obtain stress-strain response curves at dangerous sections; - Use SN curve and Miner damage accumulation theory to evaluate the total allowable number of cycles of the heat storage device.

[0029] In the remaining life assessment and early warning mechanism of step S4, the remaining life is assessed in real time using the formula: remaining life N_remain = total cycle life N_total - number of cycles used N_used, and the status is graded according to the following strategy: - Remaining life>50%: Normal operation - Remaining life span 20%~50%: Regular monitoring is recommended.

[0030] - Remaining life < 20%: Warning, repair or replacement recommended Furthermore, the method also includes a visualization platform and remote monitoring: Real-time display of heat storage operating parameters and fatigue status via industrial SCADA systems or web visualization platforms, enabling multi-terminal remote access. Supports push notifications (e.g., SMS, email, APP notifications, etc.).

[0031] The embodiment of the present invention has the following beneficial effects through the above method: improving the accuracy of fatigue life management of heat accumulators; achieving full-cycle real-time monitoring to avoid sudden failures; reducing safety accidents caused by fatigue damage; providing a scientific basis for equipment maintenance and replacement; and being applicable to various types of pressure vessels with obvious cyclic operation characteristics.

[0032] In a second embodiment of the present invention, in order to better implement the method provided in the embodiment of the present invention, the embodiment of the present invention further provides a system based on the above method. The meanings of the terms are the same as those in the above method, and the specific implementation details can be referred to the description in the method embodiment.

[0033] See also Figure 5 , Figure 5 This is a schematic diagram of the structure of a system provided by an embodiment of the present invention, wherein the system may include a data acquisition module, a real-time fatigue recognition module, a simulation module, and an evaluation module, wherein: Data acquisition module, used to collect real-time pressure and temperature data of the heat accumulator; Real-time fatigue recognition module, used to judge the change amplitude of pressure data and temperature data according to standards, identify and accumulate the number of fatigue cycles; A simulation module for calculating the theoretical total fatigue life of the heat accumulator based on the finite element analysis method; The evaluation module is used to evaluate the remaining life in real time by the difference between the theoretical total fatigue life and the accumulated number of fatigue cycles.

[0034] In another specific example, the fatigue cycle identification criteria include: a pressure change exceeding a magnitude specified by a relevant standard; and a temperature change exceeding a magnitude specified by a relevant standard.

[0035] In another specific example, the system includes multiple pressure and temperature sensors; a PLC data acquisition unit; a central processing server; a display terminal and an alarm module.

[0036] In another specific example, the system supports multiple heat storage devices to be connected in parallel and run analysis independently.

[0037] In another specific example, the system has functions such as data export, report generation, and remote alarm push.

[0038] In a third embodiment of the present invention, a steel plant with two converter systems and a shared steam accumulator was used as an example. Finite element analysis results showed a total allowable number of cycles of 221,200. The accumulator was equipped with two pressure sensors and two temperature sensors, and real-time data was connected to the plant control system. Within three months of its launch, the system identified a cumulative 3,122 fatigue cycles. The current remaining number of cycles was 221,200 - 3,122 = 218,078, indicating 98.5% of the accumulator's cycle life remained. The system also automatically generates monthly periodic reports and indicates the next inspection time point. This system accurately digitizes cycle life, providing a basis for production decision-making while also improving the safety of fatigue vessel operation.

[0039] The above is a detailed introduction to a method and system for real-time monitoring of fatigue life of a heat accumulator provided by an embodiment of the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there may be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for real-time monitoring of fatigue life of a heat accumulator, characterized in that: include: Real-time collection of pressure and temperature data of heat accumulator; Determine the change range of pressure and temperature data according to the standard, identify and accumulate the number of fatigue cycles; The theoretical total fatigue life of the heat accumulator is calculated based on the finite element analysis method, and the remaining life is evaluated in real time by the difference between the theoretical total fatigue life and the accumulated number of fatigue cycles.

2. The method according to claim 1, characterized in that The real-time collected pressure and temperature data are transmitted to the server through PLC, and a historical database containing timestamps, pressure values, and temperature values ​​is established through the server.

3. The method according to claim 2, characterized in that The determination of the change range of pressure data and temperature data according to the standard, and identification and accumulation of fatigue cycles include: Refer to the relevant provisions in the pressure vessel analysis and design standards including JB4732 or GB4732, establish a fatigue cycle identification strategy, and identify and accumulate the number of fatigue cycles according to the fatigue cycle identification strategy.

4. The method according to claim 3, characterized in that The calculation of the theoretical total fatigue life of the heat accumulator based on the finite element analysis method includes: A three-dimensional structural model of the heat accumulator was established, and typical operating pressure and temperature changes were applied to the three-dimensional structural model based on thermal-mechanical coupling boundary conditions. The stress-strain response curve at the dangerous section is obtained, and the theoretical total fatigue life of the heat accumulator is evaluated using the SN curve and Miner damage accumulation theory.

5. The method according to any one of claims 1 to 4, characterized in that The method further comprises: The operating parameters and fatigue status of the heat accumulator are displayed in real time through the industrial SCADA system or Web visualization platform, and alarm push is supported.

6. A real-time monitoring system for fatigue life of heat accumulator, characterized in that: include: Data acquisition module, used to collect real-time pressure and temperature data of the heat accumulator; Real-time fatigue recognition module, used to judge the change amplitude of pressure data and temperature data according to standards, identify and accumulate the number of fatigue cycles; A simulation module for calculating the theoretical total fatigue life of the heat accumulator based on the finite element analysis method; The evaluation module is used to evaluate the remaining life in real time by the difference between the theoretical total fatigue life and the accumulated number of fatigue cycles.

7. The system according to claim 6, characterized in that The real-time collected pressure and temperature data are transmitted to the server through PLC, and a historical database containing timestamps, pressure values, and temperature values ​​is established through the server.

8. The system according to claim 7, characterized in that The real-time fatigue identification module is used to establish a fatigue cycle identification strategy by referring to relevant provisions in the pressure vessel analysis and design standards including JB4732 or GB4732, and to identify and accumulate the number of fatigue cycles according to the fatigue cycle identification strategy.

9. The system according to claim 8, characterized in that The simulation module is used to establish a three-dimensional structural model of the heat accumulator, apply typical operating pressure and temperature changes to the three-dimensional structural model based on thermal-mechanical coupling boundary conditions; obtain stress-strain response curves at critical sections, and use SN curves and Miner damage accumulation theory to evaluate the theoretical total fatigue life of the heat accumulator.

10. The system according to any one of claims 6 to 9, characterized in that: The system further comprises: The display module is used to display the operating parameters and fatigue status of the heat accumulator in real time through the industrial SCADA system or Web visualization platform, and supports alarm push.

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