Boiler pipeline oxide skin stress analysis and spalling allowable stress calculation and judgment method

Abstract

The invention provides a boiler pipeline oxide skin stress analysis and stripping allowable stress calculation and judgment method, and belongs to the technical field of oxide skin stress calculation and stress analysis. The method comprises the steps that a tensile force measuring device is adopted to measure the critical tensile force when the oxide skin on any unit area of the inner wall of a boiler heating surface pipe is stripped; the nominal limit tensile stress of the oxide skin is calculated according to the critical tensile force; measuring the critical shearing force when the oxide skin is peeled off by adopting a drawing experiment method; the nominal limit shear stress of the oxide skin is calculated according to the critical shear force; a first safety factor is introduced, allowable tensile stress is calculated based on the nominal limit tensile stress, and a second safety factor is introduced, and allowable shear stress is calculated based on the nominal limit shear stress; and based on oxide skin stress analysis, according to the allowable tensile stress and the allowable shear stress, stripping judgment is performed on the oxide skin so as to predict pipeline oxide skin accumulation and blockage conditions, and safe and stable operation of boiler equipment is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of oxide scale stress calculation and force analysis, and in particular to a method for calculating and determining the allowable stress of oxide scale of a boiler pipe and spalling. Background Art

[0002] Under the conditions of high-parameter operation and deep peak-shaving of thermal power units, new challenges are posed to the technical supervision of metals in power plant boilers. Complex operating conditions can easily lead to unstable combustion in the furnace, and the corresponding materials of the high-temperature heating surface have less and less margin for over-temperature.

[0003] On the one hand, the inner wall of the boiler pipe heating surface is oxidized and corroded due to the action of water vapor and other factors, generating oxide scale. The formation of oxide scale reduces the thermal conductivity of the pipe, affects the heat transfer efficiency of the pipe, and reduces the effective wall thickness of the pipe. On the other hand, the peeled oxide scale accumulates at the elbow of the pipe under the action of gravity, causing blockage, reducing the steam flow in the boiler pipe, and when the blockage is serious, it may also cause the boiler pipe to burst.

[0004] In the prior art, the accuracy of allowable stress and force analysis calculation when the boiler pipe oxide scale is peeled off is low. Therefore, how to improve the accuracy of allowable stress and force analysis calculation when the boiler pipe oxide scale is peeled off has become a problem to be solved. Summary of the invention

[0005] The purpose of this application is to provide a method for calculating and determining the allowable stress of boiler pipe oxide scale stress analysis and spalling, which can solve the problem of low accuracy of boiler pipe oxide scale stress analysis and allowable stress calculation during spalling in the prior art.

[0006] In a first aspect, an embodiment of the present application provides a method for analyzing the stress of oxide scale on boiler pipes and calculating and determining the allowable stress of spalling, the method comprising: A tension measuring device is used to measure the critical tension when the oxide scale on any unit area of ​​the inner wall of the boiler heating surface tube peels off; Calculate the nominal ultimate tensile stress of the oxide scale based on the critical tensile force; The critical shear force during oxide scale peeling was measured by pull-out test method. Calculate the nominal limiting shear stress of the oxide scale based on the critical shear force; The first safety factor is introduced to calculate the allowable tensile stress based on the nominal ultimate tensile stress, and the second safety factor is introduced to calculate the allowable shear stress based on the nominal ultimate shear stress; Based on the allowable tensile stress and allowable shear stress, the oxide scale is subjected to stress analysis and peeling judgment is made to predict the accumulation and blockage of oxide scale in the pipeline and determine whether the equipment is operating safely.

[0007] In a possible implementation manner of the first aspect, the tension measuring device includes a push-pull force gauge; using the tension measuring device to measure the critical tension when the oxide scale on any unit area of ​​the inner wall of the boiler heating surface tube peels off, including: Based on the push-pull dynamometer, a tensile force is applied to the oxide scale in a direction parallel to the oxide scale until the oxide scale falls off the heated surface tube, and the critical tensile force is measured.

[0008] In a possible implementation manner of the first aspect, before calculating the nominal ultimate tensile stress of the oxide scale according to the critical tensile force, the method further includes: The thickness of the oxide scale peeled off in the direction parallel to the oxide scale is measured by a thickness gauge, and the width of the oxide scale peeled off is measured by a vernier caliper; based on the thickness and width of the oxide scale peeled off in the direction parallel to the oxide scale, the first cross-sectional area of ​​the oxide scale is calculated, and the specific calculation formula is as follows:

[0009] in, represents the first cross-sectional area, It indicates the thickness of the oxide scale peeled off in the direction parallel to the oxide scale. Indicates the width of the oxide scale peeling off in the direction parallel to the oxide scale.

[0010] In a possible implementation of the first aspect, calculating the nominal ultimate tensile stress of the oxide scale according to the critical tensile force includes: The quotient of the critical tensile force and the first cross-sectional area is taken as the nominal ultimate tensile stress. The specific calculation formula is as follows:

[0011] in, represents the nominal ultimate tensile stress, Indicates the critical tension.

[0012] In a possible implementation of the first aspect, a pull-out test method is used to measure the critical shear force during oxide scale peeling, including: A pulling instrument is used to apply a pulling force to the oxide scale in a direction perpendicular to the oxide scale until the oxide scale falls off the heated surface tube, and an adhesion tester is used to measure the critical shear force.

[0013] In a possible implementation manner of the first aspect, before calculating the nominal limiting shear stress of the oxide scale according to the critical shear force, the method further includes: The thickness of the oxide scale peeled off in a direction perpendicular to the oxide scale is measured using a thickness gauge, and the length of the oxide scale peeled off is measured using a vernier caliper; based on the thickness and length of the oxide scale peeled off in a direction perpendicular to the oxide scale, the second cross-sectional area of ​​the oxide scale is calculated, and the specific calculation formula is as follows:

[0014] in, represents the second cross-sectional area, It indicates the thickness of the oxide scale peeled off in the direction perpendicular to the oxide scale. Indicates the length of the oxide scale peeling off in the direction perpendicular to the oxide scale.

[0015] In a possible implementation of the first aspect, calculating the nominal limiting shear stress of the oxide scale according to the critical shear force includes: Based on the stress analysis, the quotient of the critical shear force and the second cross-sectional area is taken as the nominal limiting shear stress. The specific calculation formula is as follows:

[0016] in, represents the nominal ultimate shear stress, represents the critical shear stress.

[0017] In a possible implementation of the first aspect, a first safety factor is introduced to calculate the allowable tensile stress based on the nominal ultimate tensile stress, and a second safety factor is introduced to calculate the allowable shear stress based on the nominal ultimate shear stress, including: The quotient of the nominal ultimate tensile stress and the first safety factor is taken as the allowable tensile stress. The specific calculation formula is as follows:

[0018] in, represents the allowable tensile stress, Represents the first safety factor, >1; The quotient of the nominal limit shear stress and the second safety factor is taken as the allowable shear stress. The specific calculation formula is as follows:

[0019] in, represents the allowable shear stress, Represents the second safety factor, >1.

[0020] In a possible implementation manner of the first aspect, the force analysis includes: Calculate the scale gravity according to the following formula:

[0021] in, represents the scale gravity, Indicates the quality of oxide scale, represents the acceleration due to gravity, represents the oxide scale density, represents the volume of oxide scale, Indicates the oxide scale thickness, Indicates the length of oxide scale, Indicates the width of the oxide scale; The force exerted by the working fluid flow on the oxide scale is calculated according to the following formula:

[0022] in, It represents the force of working fluid flow on oxide scale, represents the density of the working fluid, Indicates the quality of oxide scale, Indicates the area of ​​the oxide scale affected by the working fluid flow; The thermal expansion force is calculated according to the following formula:

[0023] in, represents the thermal expansion force, represents the Young's modulus of the oxide scale, represents the temperature change, represents the thermal expansion coefficient of the oxide scale, Indicates the thermal expansion coefficient of the heated surface tube, Indicates the contact area between the oxide scale and the heated surface tube. Indicates the angle between the oxide scale and the heated surface tube.

[0024] In a possible implementation manner of the first aspect, the force analysis further includes: The tensile force along the scale direction is calculated according to the following formula:

[0025] in, represents the tensile force along the scale direction, It indicates the decomposition amount of the force exerted by the working fluid flow on the oxide scale along the direction of the oxide scale. Indicates the decomposition amount of the oxide scale gravity along the direction of the oxide scale, Indicates the decomposition of thermal expansion force along the oxide scale direction, Indicates the angle between the heating surface tube and the horizontal direction; The shear force perpendicular to the scale direction is calculated according to the following formula:

[0026] in, represents the shear force perpendicular to the scale direction, It indicates the decomposition amount of the force exerted by the working fluid flow on the oxide scale in the direction perpendicular to the oxide scale. It indicates the decomposition amount of the oxide scale due to gravity in the direction perpendicular to the oxide scale. Indicates the decomposition of thermal expansion force in the direction perpendicular to the oxide scale.

[0027] In a possible implementation manner of the first aspect, the force analysis further includes: The tensile stress of the oxide scale on the pipe during boiler operation is calculated according to the following formula:

[0028] in, Indicates the tensile stress on the oxide scale of the pipe during boiler operation. , , Indicates a replacement variable; The shear stress on the oxide scale of the pipe during boiler operation is calculated according to the following formula:

[0029]

[0030] in, Indicates the shear stress on the oxide scale of the pipe. , , Indicates a replacement variable; The tensile stress when the oxide scale does not fall off satisfies the following conditions:

[0031] in, represents the nominal ultimate tensile stress; like , the oxide scale falls off; The shear stress when the oxide scale does not fall off satisfies the following conditions:

[0032] in, represents the nominal ultimate shear stress; like , the oxide scale falls off.

[0033] In a second aspect, an embodiment of the present application provides a device for calculating allowable stress and determining peeling when oxide scale peels off a boiler pipe, the device comprising: The first measuring unit is used to measure the critical tension when the oxide scale on any unit area of ​​the inner wall of the boiler heating surface tube is peeled off by using a tension measuring device; A first calculation unit is used to calculate the nominal ultimate tensile stress of the oxide scale according to the critical tensile force; The second measuring unit is used to measure the critical shear force when the oxide scale peels off by a pulling test method; A second calculation unit is used to calculate the nominal limiting shear stress of the oxide scale according to the critical shear force; A third calculation unit is used to introduce a first safety factor to calculate the allowable tensile stress based on the nominal ultimate tensile stress, and introduce a second safety factor to calculate the allowable shear stress based on the nominal ultimate shear stress; The spalling judgment unit is used to judge the spalling of oxide scale based on force analysis, according to the allowable tensile stress and allowable shear stress, so as to predict the accumulation and blockage of oxide scale in the pipeline and determine whether the equipment operation is safe.

[0034] In a third aspect, an embodiment of the present application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the boiler pipe oxide scale stress analysis and spalling allowable stress calculation and determination method of any one of the above-mentioned first aspects is implemented.

[0035] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the boiler pipe oxide scale stress analysis and spalling allowable stress calculation and determination method of any one of the above-mentioned first aspects.

[0036] In a fifth aspect, an embodiment of the present application provides a computer program product. When the computer program product runs on an electronic device, the electronic device executes the boiler pipe oxide scale stress analysis and spalling allowable stress calculation and determination method according to any one of the above-mentioned first aspects.

[0037] The present application scheme first measures the critical tensile force when the oxide scale on the inner wall of the boiler heating surface tube peels off, and calculates the nominal ultimate tensile stress based on the critical tensile force. At the same time, the critical shear force when the oxide scale peels off is measured, and the nominal ultimate shear stress is calculated based on the critical shear force. Then, a first safety factor is introduced, and the allowable tensile stress is calculated based on the nominal ultimate tensile stress. A second safety factor is introduced, and the allowable shear stress is calculated based on the nominal ultimate shear stress. Finally, based on the force analysis, the oxide scale is judged to peel off according to the allowable tensile stress and the allowable shear stress, so as to predict the accumulation and blockage of the oxide scale in the pipeline and determine whether the equipment operation is safe.

[0038] This application scheme calculates the nominal limit stress, introduces a safety factor to calculate the allowable tensile stress and the allowable shear stress, and performs a force analysis. This can improve the accuracy of the force analysis of boiler pipe oxide scale and the calculation of the allowable stress during peeling, and predict the accumulation and blockage of pipe oxide scale, accurately determine whether the equipment is running safely, and take appropriate measures in a timely manner to deal with the impact of oxide scale peeling on the safe operation of the equipment, thereby ensuring the safe operation of the boiler equipment.

[0039] The application scheme can accurately calculate the stress condition of the oxide scale of the boiler pipe and provide accurate criteria for oxide scale peeling, thereby avoiding over-temperature and pipe bursting due to blockage of the pipe due to oxide scale peeling, and even unit shutdown, and has strong ease of use and practicality.

[0040] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0042] Figure 1 It is a schematic diagram of the steps of the boiler pipe oxide scale stress analysis and spalling allowable stress calculation and determination method provided in the embodiment of the present application; Figure 2 It is a schematic diagram of the stress analysis of the oxide scale on the unit area of ​​the heating surface tube provided in the embodiment of the present application; Figure 3 It is a structural schematic diagram of a boiler pipe oxide scale stress analysis and spalling allowable stress calculation and determination device provided in an embodiment of the present application; Figure 4 It is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0044] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or photovoltaic components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, photovoltaic components and / or combinations thereof.

[0045] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0046] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0047] As used in this specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0048] In addition, in the description of the present application, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0049] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0050] In response to the worsening environment and climate, the world's energy structure is undergoing great changes. Countries focus on the development of renewable energy, such as hydropower, wind power, solar energy, and nuclear energy. However, compared with other energy sources, coal consumption still dominates, and its absolute amount and share are still the largest. In order to achieve the national development goals of "carbon peak and carbon neutrality", improving quality, high efficiency, cleanliness, and low carbon are the inevitable trends in the development of coal-fired power.

[0051] Under the high-parameter operation and deep peak-shaving operation conditions of thermal power units, new challenges are posed to the technical supervision of power station boiler metal. Complex operating conditions can easily cause unstable combustion in the furnace, and the corresponding materials of the high-temperature heating surface have less and less margin for over-temperature.

[0052] On the one hand, thermal power station units operate in a long-term high-temperature environment, and the inner wall of the boiler pipe heating surface undergoes oxidation corrosion due to the effects of water vapor and other factors, generating oxide scale. The formation of oxide scale reduces the thermal conductivity of the pipe, affects the heat transfer efficiency of the pipe, and reduces the effective wall thickness of the pipe. When the steam outlet temperature of the pipe remains unchanged, the presence of oxide scale will cause the pipe to overheat for a long time, leading to a series of adverse consequences such as increased oxidation, increased metal creep rate, tissue aging and performance degradation, and causing the boiler device pipe to fail prematurely.

[0053] On the other hand, due to the large difference in thermal expansion coefficient between the oxide scale and the matrix, the thermal stress induced by the temperature change during the shutdown and startup process may cause the oxide scale to partially peel off. The peeled oxide scale accumulates at the lower elbow of the pipe under the action of gravity, causing blockage and reducing the steam flow in the boiler tube. If the blockage is serious, it may also cause the boiler tube to burst. Therefore, it is very important to study the force analysis process when the oxide scale on the inner wall of the heating surface tube peels off.

[0054] In the prior art, the accuracy of the boiler pipe oxide scale stress analysis and the allowable stress calculation when it peels off is low. Therefore, how to improve the accuracy of the boiler pipe oxide scale stress analysis and the allowable stress calculation when it peels off has become a problem to be solved.

[0055] In response to the above-mentioned defects, an embodiment of the present application provides a method for calculating and determining the allowable stress for the oxide scale of a boiler pipe when it is subjected to stress analysis and spalling. First, the critical tensile force when the oxide scale on the inner wall of the boiler heating surface tube is peeled off is measured, and the nominal ultimate tensile stress is calculated based on the critical tensile force. At the same time, the critical shear force when the oxide scale is peeled off is measured, and the nominal ultimate shear stress is calculated based on the critical shear force. Then, a first safety factor is introduced, and the allowable tensile stress is calculated based on the nominal ultimate tensile stress. A second safety factor is introduced, and the allowable shear stress is calculated based on the nominal ultimate shear stress. Finally, based on the stress analysis, the oxide scale is peeled off according to the allowable tensile stress and the allowable shear stress, so as to predict the accumulation and blockage of the oxide scale on the pipeline and ensure the safe and stable operation of the boiler equipment.

[0056] The present application scheme calculates the nominal limit stress, introduces a safety factor to calculate the allowable tensile stress and the allowable shear stress, and performs a stress analysis, thereby improving the accuracy of the stress analysis of the boiler pipe oxide scale and the calculation of the allowable stress during peeling, and accurately determining whether the equipment is operating safely. When the oxide scale peeling affects the safe operation of the equipment, appropriate measures can be taken in a timely manner to ensure the safe operation of the boiler equipment.

[0057] The application scheme can accurately calculate the stress condition of the oxide scale of the boiler pipe and provide accurate criteria for oxide scale peeling, thereby avoiding over-temperature pipe bursting and even unit shutdown caused by pipe blockage due to oxide scale peeling, and has strong ease of use and practicality.

[0058] This application scheme solves the problem of analyzing the stress of the oxide scale on the inner wall of the boiler heating surface tube of the thermal power unit and measuring the critical force when it peels off, and further provides a theoretical basis and practical guidance for analyzing and studying various problems such as oxide scale peeling, ensuring the safe and stable operation of the unit.

[0059] The specific process implemented by this application is introduced below through specific embodiments.

[0060] See also Figure 1 , Figure 1 Schematic diagram of the steps of the boiler pipe oxide scale stress analysis and spalling allowable stress calculation and determination method provided in the embodiment of the present application. Figure 1 As shown, the method may include the following steps: S101, using a tension measuring device, measure the critical tension when the oxide scale on any unit area of ​​the inner wall of the boiler heating surface tube peels off.

[0061] According to one embodiment of the present application, the tension measuring device includes a push-pull force gauge; the tension measuring device is used to measure the critical tension when the oxide scale on any unit area of ​​the inner wall of the boiler heating surface tube peels off, including: Based on the push-pull dynamometer, a tensile force is applied to the oxide scale in a direction parallel to the oxide scale until the oxide scale falls off the heated surface tube, and the critical tensile force is measured.

[0062] In some embodiments, a small push-pull force gauge is used to test the tensile force when the oxide scale peels off. First, the patch is pasted on the oxide scale to be tested. After the glue is dry, a small push-pull force gauge is used to perform a tensile test parallel to the direction of the oxide scale, and force is gradually applied until the oxide scale falls off the pipe. At this time, the critical tensile force required for the oxide scale to fall off the pipe can be obtained. F a .

[0063] S102, calculate the nominal ultimate tensile stress of the oxide scale based on the critical tensile force.

[0064] According to one embodiment of the present application, before calculating the nominal ultimate tensile stress of the oxide scale according to the critical tensile force, the method further includes: The thickness of the oxide scale peeled off in the direction parallel to the oxide scale is measured by a thickness gauge, and the width of the oxide scale peeled off is measured by a vernier caliper; based on the thickness and width of the oxide scale peeled off in the direction parallel to the oxide scale, the first cross-sectional area of ​​the oxide scale is calculated, and the specific calculation formula is as follows:

[0065] in, represents the first cross-sectional area, It indicates the thickness of the oxide scale peeled off in the direction parallel to the oxide scale. Indicates the width of the oxide scale peeling off in the direction parallel to the oxide scale.

[0066] In one embodiment, a thickness gauge and a vernier caliper are used to measure the thickness and width of the peeled oxide scale, and the specific values ​​are recorded: the thickness and width of the oxide scale, so as to obtain a first cross-sectional area of ​​the oxide scale.

[0067] According to one embodiment of the present application, the nominal ultimate tensile stress of the oxide scale is calculated according to the critical tensile force, including: The quotient of the critical tensile force and the first cross-sectional area is taken as the nominal ultimate tensile stress. The specific calculation formula is as follows:

[0068] in, represents the nominal ultimate tensile stress, represents the critical tensile force. Therefore, it can be seen that when the nominal ultimate tensile stress is The oxide scale peels off and no longer adheres to the heated surface tube.

[0069] S103, the critical shear force during oxide scale peeling is measured by pull-out test method.

[0070] According to one embodiment of the present application, a pull-out test method is used to measure the critical shear force during oxide scale peeling, including: A pulling instrument is used to apply a pulling force to the oxide scale in a direction perpendicular to the oxide scale until the oxide scale falls off the heated surface tube, and an adhesion tester is used to measure the critical shear force.

[0071] In one embodiment, a pull-out test method is used to test the shear force when the oxide scale peels off. First, the sensor head of the pull-out instrument is glued to the oxide scale to be measured. After the glue is dry, a portable adhesion tester is used to test perpendicular to the direction of the oxide scale, and the load is gradually increased until the oxide scale falls off the heated surface pipe. At this time, the critical shear force required for the oxide scale to fall off the pipeline can be obtained. F b .

[0072] S104, calculate the nominal limiting shear stress of the oxide scale based on the critical shear force.

[0073] According to one embodiment of the present application, before calculating the nominal limiting shear stress of the oxide scale according to the critical shear force, the method further includes: The thickness of the oxide scale peeled off in a direction perpendicular to the oxide scale is measured using a thickness gauge, and the length of the oxide scale peeled off is measured using a vernier caliper; based on the thickness and length of the oxide scale peeled off in a direction perpendicular to the oxide scale, the second cross-sectional area of ​​the oxide scale is calculated, and the specific calculation formula is as follows:

[0074] in, represents the second cross-sectional area, It indicates the thickness of the oxide scale peeled off in the direction perpendicular to the oxide scale. Indicates the length of the oxide scale peeling off in the direction perpendicular to the oxide scale.

[0075] In one embodiment, a thickness gauge and a vernier caliper are used to measure the thickness and length of the peeled oxide scale, and the specific values ​​are recorded: the width and length of the oxide scale, so as to obtain the second cross-sectional area of ​​the oxide scale.

[0076] According to one embodiment of the present application, the nominal limiting shear stress of the oxide scale is calculated according to the critical shear force, including: The quotient of the critical shear force and the second cross-sectional area is taken as the nominal limiting shear stress. The specific calculation formula is as follows:

[0077] in, represents the nominal ultimate shear stress, represents the critical shear force. Therefore, it can be seen that when the nominal limiting shear stress is The oxide scale peels off and no longer adheres to the heated surface tube.

[0078] It should be noted that there is no order of precedence for calculating the nominal ultimate tensile stress and the nominal ultimate shear stress, and they are performed simultaneously.

[0079] S105, introducing a first safety factor, calculating the allowable tensile stress based on the nominal ultimate tensile stress, and introducing a second safety factor, calculating the allowable shear stress based on the nominal ultimate shear stress.

[0080] According to one embodiment of the present application, a first safety factor is introduced to calculate the allowable tensile stress based on the nominal ultimate tensile stress, and a second safety factor is introduced to calculate the allowable shear stress based on the nominal ultimate shear stress, including: The quotient of the nominal ultimate tensile stress and the first safety factor is taken as the allowable tensile stress. The specific calculation formula is as follows:

[0081] in, represents the allowable tensile stress, Represents the first safety factor, >1.

[0082] The quotient of the nominal limit shear stress and the second safety factor is taken as the allowable shear stress. The specific calculation formula is as follows:

[0083] in, represents the allowable shear stress, Represents the second safety factor, >1.

[0084] In some embodiments, the specific values ​​of the nominal ultimate tensile stress and the nominal ultimate shear stress can be obtained through testing. At the same time, in practical applications, the allowable stress is a basic data in mechanical design and engineering structure design, which is obtained by dividing the nominal stress by the corresponding safety factor. , the corresponding allowable tensile stress can be obtained and the allowable shear stress is .

[0085] In one embodiment, a strength condition may be established:

[0086]

[0087] It should be noted that during the frequent deep peak-shaving operation of thermal power units, the oxide scale adheres to the inner wall of the heating surface tube, mainly under the action of its own gravity and the flow of the working fluid. In addition, there is a large difference in the thermal expansion coefficient between the oxide scale and the pipeline matrix, and due to temperature changes, there is a large thermal expansion force between the heating surface tube and the oxide scale.

[0088] See also Figure 2 , Figure 2 Schematic diagram of the stress analysis of the oxide scale per unit area of ​​the heating surface tube provided in the embodiment of the present application. Figure 2 As shown, ① is the working fluid flow direction, ② is the heated surface tube, ③ is the horizontal plane, ④ is the oxide scale (indicated in red), and ⑤ is the contact point between the oxide scale and the tube (indicated in blue).

[0089] According to one embodiment of the present application, the force analysis includes: Calculate the scale gravity according to the following formula:

[0090] in, represents the scale gravity, Indicates the quality of oxide scale, represents the acceleration due to gravity, represents the oxide scale density, represents the volume of oxide scale, Indicates the oxide scale thickness, Indicates the length of oxide scale, Indicates the width of the oxide scale.

[0091] The force exerted by the working fluid flow on the oxide scale is affected by the working fluid density and the working fluid flow velocity. The force exerted by the working fluid flow on the oxide scale is calculated according to the following formula:

[0092] in, It represents the force of working fluid flow on oxide scale, represents the density of the working fluid, Indicates the quality of oxide scale, Indicates the area of ​​the oxide scale affected by the working fluid flow; The magnitude of the thermal expansion force is affected by the thermal expansion coefficient of the oxide scale, the thermal expansion coefficient of the heated surface tube, the Young's modulus of the oxide scale, the temperature change, and the size of the cross-sectional area of ​​the oxide scale. The thermal expansion force is calculated according to the following formula:

[0093] in, represents the thermal expansion force, represents the Young's modulus of the oxide scale, represents the temperature change, represents the thermal expansion coefficient of the oxide scale, Indicates the thermal expansion coefficient of the heated surface tube, Indicates the contact area between the oxide scale and the heated surface tube. Indicates the angle between the oxide scale and the heated surface tube.

[0094] Please continue to see Figure 2 , take any oxide scale on any unit area of ​​the heating surface tube for force analysis. Assume that the oxide scale forms a certain angle with the heating surface tube, recorded as β , the heating surface tube forms a certain angle with the horizontal direction, recorded as α During the normal operation of the thermal power unit, the force is decomposed according to the parallelogram rule.

[0095] In some embodiments, gravity F G Can be decomposed into F G’ and perpendicular to the oxide scale direction F G’’ ,and , . The flow force of the working fluid (the force of the working fluid flow on the oxide scale) Can be decomposed into Fs' and perpendicular to the oxide scale direction Fs'' ,and , .

[0096] Thermal expansion force Can be decomposed into F T’ and perpendicular to the oxide scale direction F T’’ ,and , .

[0097] According to one implementation of the present application, the force analysis further includes: The tensile force along the scale direction is calculated according to the following formula:

[0098] in, represents the tensile force along the scale direction, It indicates the decomposition amount of the force exerted by the working fluid flow on the oxide scale along the direction of the oxide scale. Indicates the decomposition amount of the oxide scale gravity along the direction of the oxide scale, Indicates the decomposition of thermal expansion force along the oxide scale direction, Indicates the angle between the heated surface tube and the horizontal direction.

[0099] The shear force perpendicular to the scale direction is calculated according to the following formula:

[0100] in, represents the shear force perpendicular to the scale direction, It indicates the decomposition amount of the force exerted by the working fluid flow on the oxide scale in the direction perpendicular to the oxide scale. It indicates the decomposition amount of the oxide scale due to gravity in the direction perpendicular to the oxide scale. Indicates the decomposition of thermal expansion force in the direction perpendicular to the oxide scale.

[0101] From the above, it can be seen that the change of oxide scale stress is mainly related to the oxide scale length, oxide scale width, oxide scale thickness, working fluid flow rate, and temperature change. When the oxide scale length, oxide scale width, oxide scale thickness, working fluid flow rate, and temperature change increase, the oxide scale stress increases.

[0102] The oxide scale is a brittle material. From the beginning of loading until the sample is broken, the deformation of the sample is very small, there is no obvious straight line segment, almost no plastic deformation, and no yield and necking phenomenon. Therefore, there is only the stress value at the time of fracture. According to one embodiment of the present application, the force analysis also includes: The tensile stress of the oxide scale on the pipe during boiler operation is calculated according to the following formula:

[0103] in, Indicates the tensile stress on the oxide scale of the pipe during boiler operation. , , Indicates a substitution variable.

[0104] The shear stress on the oxide scale of the pipe during boiler operation is calculated according to the following formula:

[0105] in, Indicates the shear stress on the oxide scale of the pipe. , , Indicates a substitution variable.

[0106] It should be noted that the change of oxide scale stress is mainly related to the oxide scale length, oxide scale width, oxide scale thickness, working fluid flow velocity, and temperature change. When the oxide scale length, oxide scale width, oxide scale thickness, working fluid flow velocity, and temperature change increase, the stress of the oxide scale itself increases.

[0107] In some embodiments, the corresponding nominal limit stress can be calculated from the limit load when the oxide scale breaks under tension or shear force. The tensile stress when the oxide scale does not fall off satisfies the following conditions:

[0108] in, represents the nominal ultimate tensile stress; On the contrary, the oxide scale will fall off.

[0109] The shear stress when the oxide scale does not fall off satisfies the following conditions:

[0110] in, represents the nominal ultimate shear stress.

[0111] On the contrary, the oxide scale will fall off.

[0112] S106, based on the allowable tensile stress and the allowable shear stress, the oxide scale peeling is judged to predict the oxide scale accumulation and blockage in the pipeline and determine whether the equipment operation is safe.

[0113] It should be noted that when the stress of the oxide scale itself does not exceed the allowable stress, the equipment is safe in operation and the operating risk caused by the oxide scale shedding is very small. When the stress of the oxide scale itself exceeds this value, there will be safety hazards, and the probability of accidents caused by the oxide scale shedding during equipment operation is very high.

[0114] In some embodiments, when the tensile stress of the oxide scale , Shear stress of oxide scale The oxide scale will not fall off, and will not cause oxide scale accumulation and blockage, and the equipment operation is safe; when the tensile stress of the oxide scale , Shear stress of oxide scale When the oxide scale is removed, it will fall off, which will most likely cause oxide scale accumulation and blockage, making the equipment operation unsafe.

[0115] The application scheme can accurately calculate the allowable stress of boiler pipe oxide scale stress analysis and peeling, provide accurate judgment criteria for oxide scale peeling, and avoid over-temperature pipe bursting and even unit shutdown due to pipe blockage caused by oxide scale peeling.

[0116] The embodiment of the present application provides a method for calculating and determining the allowable stress for the spalling of oxide scale on boiler pipes. First, the critical tensile force when the oxide scale on the inner wall of the boiler heating surface pipe is spalled is measured, and the nominal ultimate tensile stress is calculated based on the critical tensile force. At the same time, the critical shear force when the oxide scale is spalled is measured, and the nominal ultimate shear stress is calculated based on the critical shear force. Then, a first safety factor is introduced, and the allowable tensile stress is calculated based on the nominal ultimate tensile stress. Then, a second safety factor is introduced, and the allowable shear stress is calculated based on the nominal ultimate shear stress. Finally, based on the force analysis, the oxide scale is determined to be spalled in combination with the allowable tensile stress and the allowable shear stress, so as to predict the accumulation and blockage of the oxide scale in the pipe and determine whether the equipment is operating safely.

[0117] This application scheme calculates the nominal limit stress, introduces a safety factor to calculate the allowable tensile stress and the allowable shear stress, and performs a force analysis. This can improve the accuracy of the force analysis of boiler pipe oxide scale and the calculation of the allowable stress during peeling, and predict the accumulation and blockage of pipe oxide scale, accurately determine whether the equipment is running safely, and take appropriate measures in a timely manner to deal with the impact of oxide scale peeling on the safe operation of the equipment, thereby ensuring the safe operation of the boiler equipment.

[0118] The application scheme can accurately calculate the stress condition of the oxide scale of the boiler pipe and provide accurate criteria for oxide scale peeling, thereby avoiding over-temperature and pipe bursting due to blockage of the pipe due to oxide scale peeling, and even unit shutdown, and has strong ease of use and practicality.

[0119] This application scheme solves the problem of analyzing the stress of the oxide scale on the inner wall of the boiler heating surface tube of the thermal power unit and measuring the critical force when it peels off, and further provides a theoretical basis and practical guidance for analyzing and studying various problems such as oxide scale peeling, ensuring the safe and stable operation of the unit.

[0120] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0121] Corresponding to the method of the above embodiment, Figure 3 1 is a schematic diagram of the structure of the boiler pipe oxide scale stress analysis and spalling allowable stress calculation and determination device provided in the embodiment of the present application. For the convenience of explanation, only the parts related to the embodiment of the present application are shown.

[0122] Reference Figure 3 , the device comprises: The first measuring unit 301 is used to measure the critical tension when the oxide scale on any unit area of ​​the inner wall of the boiler heating surface tube peels off by using a tension measuring device; A first calculation unit 302 is used to calculate the nominal ultimate tensile stress of the oxide scale according to the critical tensile force; The second measuring unit 303 is used to measure the critical shear force when the oxide scale peels off by using a pulling test method; A second calculation unit 304 is used to calculate the nominal limiting shear stress of the oxide scale according to the critical shear force; A third calculation unit 305 is used to introduce a first safety factor to calculate the allowable tensile stress based on the nominal ultimate tensile stress, and introduce a second safety factor to calculate the allowable shear stress based on the nominal ultimate shear stress; The spalling determination unit 306 is used to determine the spalling of the oxide scale based on the force analysis, according to the allowable tensile stress and the allowable shear stress, so as to predict the accumulation and blockage of the oxide scale in the pipeline and determine whether the equipment is running safely.

[0123] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0124] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0125] See also Figure 4 , Figure 4 Schematic diagram of the structure of the electronic device 4 provided in the embodiment of the present application. Figure 4 As shown, the electronic device 4 of this embodiment includes: at least one processor 401 ( Figure 4 Only one is shown in the figure), a memory 403, and a computer program 402 stored in the memory 403 and executable on at least one processor 401, wherein the processor 401 implements the steps in the above method embodiment when executing the computer program 402.

[0126] The electronic device 4 may be a computing device such as a desktop computer, a notebook, a PDA, or a mobile phone. The electronic device 4 may include, but is not limited to, a processor 401 and a memory 403. Those skilled in the art will appreciate that Figure 4 It is only an example of the electronic device 4 and does not constitute a limitation on the electronic device 4. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, it may also include input and output devices, network access devices, etc.

[0127] The processor 401 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware photovoltaic modules, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0128] In some embodiments, the memory 403 may be an internal storage unit of the electronic device 4, such as a hard disk or memory of the electronic device 4. In other embodiments, the memory 403 may also be an external storage device of the electronic device 4, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital card (SecureDigital, SD), a flash card (Flash Card), etc. equipped on the electronic device 4. Further, the memory 403 may also include both an internal storage unit of the electronic device 4 and an external storage device. The memory 403 is used to store an operating system, an application program, a boot loader (Boot Loader), data, and other programs, such as program codes of a computer program, etc. The memory 403 may also be used to temporarily store data that has been output or is to be output.

[0129] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, when the present application implements all or part of the processes in the above-mentioned embodiment method, it can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, it can implement the steps applied to the method embodiment. Among them, the computer program includes computer program code, which can be in source code form, object code form, executable file or some intermediate form. The computer-readable storage medium may at least include: any entity or device that can carry the computer program code to the computing device / electronic device, recording medium, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium, such as USB flash drive, mobile hard disk, disk or optical disk. In some jurisdictions, according to legislation and patent practice, computer-readable storage media cannot be electric carrier signals and telecommunication signals.

[0130] An embodiment of the present application further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0131] An embodiment of the present application provides a computer program product. When the computer program product is run on an electronic device, the electronic device executes the steps in the above-mentioned method embodiments.

[0132] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0133] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0134] In the embodiments provided in the present application, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. The device / electronic device embodiments described above are merely schematic, and the division of the above modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or photovoltaic components can be combined or integrated into another system, and some features can be ignored and not executed. Another point is that the indirect coupling, direct coupling or communication connection between each other shown or discussed can be an indirect coupling, direct coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0135] The units described above as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0136] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for analyzing the stress of boiler pipe oxide scale and calculating and determining the allowable stress of spalling, characterized in that: The method comprises: A tension measuring device is used to measure the critical tension when the oxide scale on any unit area of ​​the inner wall of the boiler heating surface tube peels off; Calculate the nominal ultimate tensile stress of the oxide scale based on the critical tensile force; The critical shear force during oxide scale peeling was measured by pull-out test method. Calculating the nominal limiting shear stress of the oxide scale based on the critical shear force; Introducing a first safety factor to calculate the allowable tensile stress based on the nominal ultimate tensile stress, and introducing a second safety factor to calculate the allowable shear stress based on the nominal ultimate shear stress; Based on the stress analysis of the oxide scale, the oxide scale peeling is determined according to the allowable tensile stress and the allowable shear stress, so as to predict the accumulation and blockage of the oxide scale in the pipeline and determine whether the equipment is running safely.

2. The method for analyzing the stress of boiler pipe oxide scale and calculating and determining the allowable stress of spalling according to claim 1 is characterized in that: The tension measuring device comprises a push-pull dynamometer; The tensile force measuring device is used to measure the critical tensile force of the oxide scale peeling off on any unit area of ​​the inner wall of the boiler heating surface tube, including: Based on the push-pull force gauge, a pulling force is applied to the oxide scale in a direction parallel to the oxide scale until the oxide scale falls off the heated surface tube, and the critical pulling force is measured.

3. The method for analyzing the stress of boiler pipe oxide scale and calculating and determining the allowable stress of spalling according to claim 2 is characterized in that: Before calculating the nominal ultimate tensile stress of the oxide scale according to the critical tensile force, the method further comprises: The thickness of the oxide scale peeled off in the direction parallel to the oxide scale is measured with a thickness gauge, and the width of the oxide scale peeled off is measured with a vernier caliper; Based on the thickness and width of the oxide scale peeled off in the direction parallel to the oxide scale, the first cross-sectional area of ​​the oxide scale is calculated. The specific calculation formula is as follows: in, represents the first cross-sectional area, It indicates the thickness of the oxide scale peeled off in the direction parallel to the oxide scale. Indicates the width of the oxide scale peeling off in the direction parallel to the oxide scale.

4. The method for analyzing the stress of boiler pipe oxide scale and calculating and determining the allowable stress of spalling according to claim 3 is characterized in that: The nominal ultimate tensile stress of the oxide scale is calculated based on the critical tensile force, including: The quotient of the critical tensile force and the first cross-sectional area is taken as the nominal ultimate tensile stress, and the specific calculation formula is as follows: in, represents the nominal ultimate tensile stress, Indicates the critical tension.

5. The method for analyzing the stress of boiler pipe oxide scale and calculating and determining the allowable stress of spalling according to claim 1 is characterized in that: The pull-out test method is used to measure the critical shear force during oxide scale peeling, including: A pulling instrument is used to apply a pulling force to the oxide scale in a direction perpendicular to the oxide scale until the oxide scale falls off the heated surface tube, and an adhesion tester is used to measure the critical shear force.

6. The method for analyzing the stress of boiler pipe oxide scale and calculating and determining the allowable stress of spalling according to claim 5 is characterized in that: Before calculating the nominal limiting shear stress of the oxide scale according to the critical shear force, the method further comprises: The thickness of the oxide scale peeled off in the direction perpendicular to the oxide scale is measured with a thickness gauge, and the length of the oxide scale peeled off is measured with a vernier caliper; Based on the thickness and length of the oxide scale peeled off in the direction perpendicular to the oxide scale, the second cross-sectional area of ​​the oxide scale is calculated. The specific calculation formula is as follows: in, represents the second cross-sectional area, It indicates the thickness of the oxide scale peeled off in the direction perpendicular to the oxide scale. Indicates the length of the oxide scale peeling off in the direction perpendicular to the oxide scale.

7. The method for analyzing the stress of boiler pipe oxide scale and calculating and determining the allowable stress of spalling according to claim 6 is characterized in that: The nominal limiting shear stress of the oxide scale is calculated based on the critical shear force, including: The quotient of the critical shear force and the second cross-sectional area is taken as the nominal limiting shear stress, and the specific calculation formula is as follows: in, represents the nominal ultimate shear stress, represents the critical shear stress.

8. The method for analyzing the stress of boiler pipe oxide scale and calculating and determining the allowable stress of spalling according to claim 4 or 7, characterized in that: Introducing a first safety factor, calculating the allowable tensile stress based on the nominal ultimate tensile stress, and introducing a second safety factor, calculating the allowable shear stress based on the nominal ultimate shear stress, comprising: The quotient of the nominal ultimate tensile stress and the first safety factor is taken as the allowable tensile stress, and the specific calculation formula is as follows: in, represents the allowable tensile stress, Represents the first safety factor, >1; The quotient of the nominal limit shear stress and the second safety factor is taken as the allowable shear stress, and the specific calculation formula is as follows: in, represents the allowable shear stress, Represents the second safety factor, >

1.

9. The method for analyzing the stress of boiler pipe oxide scale and calculating and determining the allowable stress of spalling according to claim 1 is characterized in that: Stress analysis includes: Calculate the scale gravity according to the following formula: in, represents the scale gravity, Indicates the quality of oxide scale, represents the acceleration due to gravity, represents the oxide scale density, represents the volume of oxide scale, Indicates the oxide scale thickness, Indicates the length of oxide scale, Indicates the width of the oxide scale; The force exerted by the working fluid flow on the oxide scale is calculated according to the following formula: in, It represents the force of the working fluid flow on the oxide scale. represents the density of the working fluid, Indicates the quality of oxide scale, Indicates the area of ​​the oxide scale affected by the working fluid flow; The thermal expansion force is calculated according to the following formula: in, represents the thermal expansion force, represents the Young's modulus of the oxide scale, represents the temperature change, represents the thermal expansion coefficient of the oxide scale, Indicates the thermal expansion coefficient of the heated surface tube, Indicates the contact area between the oxide scale and the heated surface tube. Indicates the angle between the oxide scale and the heated surface tube.

10. The method for analyzing the stress of boiler pipe oxide scale and calculating and determining the allowable stress of spalling according to claim 9 is characterized in that: The stress analysis also includes: The tensile force along the scale direction is calculated according to the following formula: in, represents the tensile force along the scale direction, It indicates the decomposition amount of the force exerted by the working fluid flow on the oxide scale along the direction of the oxide scale. Indicates the decomposition amount of the oxide scale gravity along the direction of the oxide scale, Indicates the decomposition of thermal expansion force along the oxide scale direction, Indicates the angle between the heating surface tube and the horizontal direction; The shear force perpendicular to the scale direction is calculated according to the following formula: in, represents the shear force perpendicular to the scale direction, It indicates the decomposition amount of the force exerted by the working fluid flow on the oxide scale in the direction perpendicular to the oxide scale. It indicates the decomposition amount of the oxide scale due to gravity in the direction perpendicular to the oxide scale. Indicates the decomposition of thermal expansion force in the direction perpendicular to the oxide scale.

11. The method for analyzing the stress of boiler pipe oxide scale and calculating and determining the allowable stress of spalling according to claim 10 is characterized in that: The stress analysis also includes: The tensile stress of the oxide scale on the pipe during boiler operation is calculated according to the following formula: in, Indicates the tensile stress on the oxide scale of the pipe during boiler operation. , , Indicates a replacement variable; The shear stress on the oxide scale of the pipe during boiler operation is calculated according to the following formula: in, Indicates the shear stress on the oxide scale of the pipe. , , Indicates a replacement variable; The tensile stress when the oxide scale does not fall off satisfies the following conditions: in, represents the nominal ultimate tensile stress; like , the oxide scale falls off; The shear stress when the oxide scale does not fall off satisfies the following conditions: in, represents the nominal ultimate shear stress; like , the oxide scale falls off.

12. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the boiler pipe oxide scale stress analysis and spalling allowable stress calculation and determination method described in any one of claims 1-11 is implemented.

13. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for analyzing the stress of boiler pipe oxide scale and calculating and determining the allowable stress of spalling according to any one of claims 1 to 11 is implemented.

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