A method for analyzing the stress of jacketed pipe
By calculating the equivalent parameters of the jacketed tube, the problem of low stress analysis speed and efficiency of jacketed tubes in the prior art is solved, and fast and efficient stress analysis is achieved to ensure the accuracy and reliability of the calculation results.
Patent Information
- Application Number
- CN202010140815.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-03-03
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2040-03-03
AI Technical Summary
The prior art simulation modeling in the stress analysis of jacketed tubes is prone to errors, resulting in unreasonable pipeline layout, nozzle stress, pipeline support frame stress or stress exceeding the standard, and the modeling process is time-consuming and labor-intensive, with low speed and efficiency. .
By calculating the equivalent outer diameter, equivalent wall thickness and equivalent medium density of the jacketed tube, a simplified stress analysis model is established, using these parameters for stress analysis, and using stress analysis software for calculation, including support frame load, primary and secondary stress, etc. Analyze until it meets industry standards.
It realizes rapid and efficient stress analysis of jacketed tubes, simple and easy to operate, and the calculation results are accurate and reliable, which significantly improves the analysis speed and efficiency.
Smart Images
Figure CN113361056B_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of petrochemical pipeline stress analysis, and in particular, to a method for analyzing the stress of a jacketed pipe. Background Art
[0002] In the petrochemical production process, the application of jacketed pipes is indispensable. This type of pipe is also the focus of pipe stress analysis. At present, the main simulation modeling method for jacketed pipe stress analysis is prone to errors. If it is found during the calculation process that the pipe layout is unreasonable, resulting in nozzle stress, pipe support frame stress or pipe stress exceeding the standard, it is necessary to modify the inner and outer pipe layouts respectively and then re-establish the association. This modeling method is time-consuming and labor-intensive, and the speed and efficiency are very low. Summary of the invention
[0003] The present invention provides a method for analyzing the stress of a jacket pipe, which can accurately and conveniently perform simulation analysis and calculation on the stress of the jacket pipe, thereby improving the analysis speed and efficiency of pipeline stress analysis.
[0004] In order to achieve the above object, the present disclosure provides a method for analyzing the stress of a jacket pipe, the method comprising: S1: calculating the equivalent outer diameter of the jacket pipe according to formula (1):
[0005]
[0006] S2: Calculate the equivalent wall thickness d of the jacket according to formula (2): 当量 ;
[0007]
[0008] S3: Calculate the equivalent medium density σ of the jacket according to formula (3): 当量 ;
[0009]
[0010] S4: Perform stress analysis according to the model parameters of the jacket pipe, wherein the model parameters include the equivalent outer diameter of the jacket pipe. Equivalent wall thickness d 当量 and equivalent medium density σ 当量 ;in, d1 and σ1 are respectively the outer diameter, wall thickness and material density of the outer tube of the jacket tube; d2 and σ2 are respectively the outer diameter, wall thickness and material density of the inner tube of the jacket tube; σ f1 is the density of the medium between the outer tube and the inner tube of the jacket tube, σ f2 are respectively the densities of the medium inside the inner tube of the jacket tube.
[0011] Optionally, the method further includes: before step S1, confirming whether the jacket tube meets the analysis conditions, and performing step S1 when the jacket tube meets the analysis conditions; the analysis conditions include: the length of the jacket tube is ≤6000mm, and the wall temperature difference between the outer tube and the inner tube is ≤50°C.
[0012] Optionally, the method further includes: when the jacket pipe does not meet the analysis conditions, checking and calculating the weld strength of the jacket end plate or jacket flange of the jacket pipe until the weld strength meets the allowable stress requirements for pipes in the ASME Pressure Piping Code B31.3.
[0013] Optionally, the model parameters in step S4 also include: the design temperature T of the jacket pipe d , calculate the temperature T c and one or more of the material parameters ε of the jacket tube.
[0014] Optionally, T is calculated according to formula (4): d , calculate T according to formula (5) c , calculate ε according to formula (6); T d =T d1 Formula (4), T c =T c1 Formula (5), ε = ε1 Formula (6); where T d1 is the design temperature of the outer tube of the jacket tube, T c1 is the operating temperature of the outer tube of the jacketed tube, and ε1 is the material parameter of the outer tube of the jacketed tube.
[0015] Optionally, the material parameter ε includes one or more of tube density, allowable stress and thermal expansion coefficient.
[0016] Optionally, the outer tube of the jacket tube is made of carbon steel or alloy steel, and the inner tube is made of the same or similar material as the outer tube.
[0017] Optionally, in step S4, stress analysis software is used to perform the stress analysis.
[0018] Optionally, analyzing the stress of the jacket pipe includes analyzing one or more of the load of a support frame of the jacket pipe, the primary stress and secondary stress of the jacket pipe, and the force on the nozzle of a connected device.
[0019] Optionally, the jacket pipe is any one of a jacket pipe with a hidden inner pipe weld and a jacket pipe with an exposed inner pipe weld.
[0020] The present disclosure establishes a simplified jacket pipe stress analysis model by adopting equivalent parameters, and adopts the simplified model to replace the complex jacket pipe stress analysis process, which has the significant advantages of fast and efficient model establishment, simple and easy model modification, and accurate and reliable calculation results.
[0021] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:
[0023] Figure 1 It is a schematic diagram of a model establishment process in one embodiment of the method for analyzing the stress of a jacket pipe disclosed in the present invention.
[0024] Figure 2 Schematic diagram of a cross-section of a jacket pipe in one embodiment of the method for analyzing stress of a jacket pipe disclosed herein.
[0025] Figure 3 It is a schematic diagram of the density distribution of the medium in the outer tube and the medium in the inner tube of the jacket tube in one embodiment of the method for analyzing the stress of the jacket tube disclosed in the present invention.
[0026] Figure 4 1 is a schematic cross-sectional view of a jacket pipe in a stress analysis model in one embodiment of a method for analyzing stress of a jacket pipe according to the present disclosure.
[0027] Figure 5 It is a schematic diagram of the node positions of each support frame and nozzle of the jacket pipe in the stress analysis model of an embodiment of an implementation manner of the method for analyzing the stress of the jacket pipe disclosed in the present invention.
[0028] Figure 6 1 is a dimensional diagram of a jacket pipe in a stress analysis model of an embodiment of a method for analyzing stress of a jacket pipe according to the present disclosure (the unit of the dimension is mm).
[0029] Figure 7 Schematic diagram of a jacket tube in a stress analysis model of a comparative example of the present disclosure.
[0030] Reference numerals
[0031] 1. Outer tube 2. Outer tube cross 3. Inner tube
[0032] 4. Rigid support frame 5. Inner tube cross 6. Spring support frame
[0033] 7. Internal locating ring 8. Jacket flange 9. Equipment nozzle
[0034] 10. Nozzle node 700. Nozzle node 65. Support frame node
[0035] 295.Support frame node 296.Support frame node 545.Support frame node
[0036] 675.Support Node DETAILED DESCRIPTION
[0037] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.
[0038] In the present disclosure, unless otherwise specified, “inside” and “outside” refer to the outline of the device itself.
[0039] like Figure 1 As shown, the present disclosure provides a method for analyzing the stress of a jacket pipe, the method comprising the following steps: S1: calculating the equivalent outer diameter of the jacket pipe according to formula (1):
[0040]
[0041] S2: Calculate the equivalent wall thickness d of the jacket according to formula (2) 当量 ;
[0042]
[0043] S3: Calculate the equivalent medium density σ of the jacket according to formula (3) 当量 ;
[0044]
[0045] S4: Stress analysis is performed based on the model parameters of the jacket pipe, which include the equivalent outer diameter of the jacket pipe Equivalent wall thickness d 当量 and equivalent medium density σ 当量 ;
[0046] Among them, Figure 2 As shown, d1 and σ1 are the outer diameter, wall thickness and material density of the outer tube of the jacket tube, respectively. d2 and σ2 are the outer diameter, wall thickness and material density of the inner tube of the jacket tube respectively; Figure 3 As shown, σ f1 is the density of the medium between the outer tube and the inner tube of the jacket, σ f2 are the densities of the medium inside the inner tube of the jacket tube, respectively.
[0047] The pipe cross section in the simplified model of the jacket pipe is as follows: Figure 4 As shown, the equivalent outer diameter in this simplified model is Equivalent wall thickness d 当量 and equivalent medium density σ 当量 Calculated by formula (1)-(3). The present disclosure establishes a simplified jacket pipe stress analysis model by using equivalent parameters, and uses the simplified model to replace the complex jacket pipe stress analysis process, which has the significant advantages of fast and efficient model establishment, simple and easy model modification, and accurate and reliable calculation results.
[0048] According to the present disclosure, before adopting the present method for stress analysis, in order to make the jacket tube meet the stress analysis requirements in the art, in one embodiment, it can be confirmed whether the length of the jacket tube and the temperature difference between the tube walls of the outer tube and the inner tube meet the analysis conditions. In one embodiment, the analysis conditions include: the length of the jacket tube ≤6000mm, and the temperature difference between the tube walls of the outer tube and the inner tube of the jacket tube ≤50°C, preferably the temperature difference between the tube walls of the outer tube and the inner tube ≤30°C. When the jacket tube meets the above analysis conditions, step S1 can be performed.
[0049] When the jacket pipe does not meet the above analysis conditions, in one embodiment, the weld strength of the jacket end plate or the jacket flange of the jacket pipe can be checked and calculated. The specific check calculation can be a conventional calculation method in the field. In one embodiment, when the temperature difference between the pipe walls of the outer pipe and the inner pipe is greater than 50°C, the length of the jacket pipe can be repeatedly adjusted until the calculated weld strength of the jacket end plate or the jacket flange meets the allowable stress range requirements of the pipe material specified in the "ASME Pressure Piping Code B31.3" to meet the limitation of the difference in thermal expansion between the inner pipe and the outer pipe of the jacket pipe, and step S1 can be performed; in another embodiment, when the temperature difference between the pipe walls of the outer pipe and the inner pipe is ≤50°C, the length of the jacket pipe can be directly trimmed to meet the analysis condition that the length of the jacket pipe is ≤6000mm, and step S1 can be performed.
[0050] According to the present disclosure, the model parameters in step S4 may also include: the design temperature T of the jacket pipe d , calculate the temperature T c and one or more of the material parameters ε of the jacket pipe, and the above parameters are used to perform stress analysis of the jacket pipe in the stress analysis software.
[0051] In a specific embodiment of the present disclosure, the design temperature T of the jacket tube can be obtained according to formula (4): d , where T d1 is the design temperature of the outer tube of the jacketed tube,
[0052] T d =T d1 Formula (4).
[0053] In a specific embodiment of the present disclosure, the temperature T can be obtained according to formula (5): c , where T c1 is the operating temperature of the outer tube of the jacketed tube,
[0054] T c =T c1 Formula (5).
[0055] In a specific embodiment of the present disclosure, the material parameter ε of the jacket tube can be obtained according to formula (6), where ε1 is the material parameter of the outer tube of the jacket tube,
[0056] ε=ε1Formula (6).
[0057] In a further specific implementation manner, the material parameter ε may include one or more parameters of pipe density, allowable stress and thermal expansion coefficient, and preferably may include allowable stress and / or thermal expansion coefficient.
[0058] The present disclosure has no limitation on the types of pipe materials for the inner pipe and the outer pipe of the jacket pipe, which can be conventionally selected in the art. The pipe material of the outer pipe of the jacket pipe can be carbon steel or alloy steel, preferably carbon steel. The pipe material of the inner pipe can be the same as or similar to that of the outer pipe, preferably the same; wherein the pipe material of the inner pipe is similar to that of the outer pipe means that the pipe density, allowable stress value and thermal expansion coefficient of the inner pipe and the outer pipe are similar. For example, in a specific embodiment, the outer pipe of the jacket pipe can be A53-B carbon steel, and the inner pipe can be A53-B carbon steel or A106-B carbon steel.
[0059] According to the present disclosure, the simplified model of the jacket pipe stress analysis can be used for processes such as load analysis of the jacket pipe support frame, primary stress analysis and secondary stress analysis of the jacket pipe, and force analysis of the nozzle of the equipment connected to the jacket pipe, and the results of its stress analysis can meet the respective industry standards and have strong practicality.
[0060] The present disclosure has no limitation on the type of jacketed pipe, which may be a conventional choice in the art, for example, it may be any one of a jacketed pipe with a concealed inner pipe weld or a semi-jacketed pipe with an exposed inner pipe weld, preferably a jacketed pipe with a concealed inner pipe weld. Using the simplified model of the present disclosure to calculate the above types of jacketed pipes has the significant advantages of fast and efficient model establishment, simple and easy model modification, and accurate and reliable calculation results.
[0061] The present disclosure is further illustrated below by way of examples, but the present disclosure is not limited thereby.
[0062] Example
[0063] like Figure 5-6As shown, the stress analysis method disclosed in the present invention is used to perform stress analysis on the inner pipe weld hidden jacket pipe, wherein the outer pipe material is A53-B carbon steel pipe, the inner pipe material is A106-B carbon steel pipe which is similar to the outer pipe material, and the length of each jacket pipe section in the pipeline is less than 6000mm (such as Figure 6 As shown), the temperature difference between the inner tube wall and the outer tube wall is 30°C;
[0064] The outer diameter of the outer tube of the jacket tube The outer tube wall thickness is 168.3mm, the outer tube wall thickness is 7.11mm, and the outer tube material density σ1 is 7840kg / m 3 ;Outer diameter of inner tube The inner tube wall thickness d2 is 6.02 mm, and the inner tube material density σ2 is 7840 kg / m 3 ; Density of the medium between the outer tube and the inner tube σ f1 2.3757kg / m 3 , the density of the medium inside the inner tube σ f2 1738.5kg / m 3 ; Design temperature of outer tube T d1 The operating temperature of the outer tube is 260°C. c1 is 147°C, and the material parameter ε1 of the outer tube is the specific parameter corresponding to A53-B;
[0065] By calculating from formula (1) to formula (6), the equivalent outer diameter can be obtained: is 168.3mm, equivalent wall thickness d 当量 is 11.45 mm, equivalent medium density σ 当量 802kg / m 3 , the design temperature of the jacket tube is T d The calculated temperature of the jacket is 260°C. c The temperature is 147℃, and the material parameter ε is the pipe density, allowable stress and thermal expansion coefficient of A53-B carbon steel pipe.
[0066] The main parameters of the pipeline stress analysis of the embodiment calculated by formula (1) to formula (6) are used to construct the pipeline analysis model of the jacketed pipe for stress analysis. The pipeline stress analysis calculation is performed by the analytical method, and the stress analysis results of the nozzle nodes of the equipment connected to the jacketed pipe are calculated by CAESAR II software as shown in Table 1 below, and the stress analysis results of each support frame node are shown in Table 2 below. Among them, the pipe fittings in the jacketed pipe combination are mainly crosses, and their stress increase coefficient and flexibility coefficient are provided by the manufacturer. The primary stress and secondary stress of the pipeline affected by them are not calculated here.
[0067] Comparative Example
[0068] like Figure 7As shown, the same stress analysis is performed using the same jacket pipe as in Example 1, and its modeling parameters are the same as in Example 1; in addition, the required parameters also include: the design temperature T of the inner pipe d1 The operating temperature of the inner tube is 230°C. c1 The temperature is 166℃, and the material parameter ε1 of the outer pipe is the pipe density, allowable stress and thermal expansion coefficient of the A106-B carbon steel pipe.
[0069] Specifically, when inputting the model, it is necessary to first establish an inner tube model according to the inner tube parameters, then establish an outer tube model according to the outer tube parameters, and then establish associations at the nodes such as the jacket flange, the jacket end plate, and the inner positioning ring between the inner and outer tubes, so as to form a stress analysis model. Among them, only in terms of the number of nodes, it is about twice the number of nodes in the embodiment, and it is also necessary to analyze and model the complex association relationship between the inner and outer tubes during modeling.
[0070] The analytical method is used to perform pipeline stress analysis. The stress analysis results of the nozzle node of the jacket pipe are calculated using CAESAR II software and are shown in Table 1 below. The stress analysis results of the support frame node are shown in Table 2 below.
[0071] Table 1: Nozzle node stress analysis results
[0072]
[0073] Table 2: Stress analysis results of support frame nodes
[0074]
[0075] It can be seen from the embodiment and the comparative example that the complex correlation between the inner tube and the outer tube in the embodiment can be modeled by the equivalent parameters calculated by equations (1) to (6), and there is no need to consider the correlation between the inner tube and the outer tube in the modeling stage as in the comparative example. Therefore, the modeling time for the correlation using the scheme of the present invention is much less than that of the comparative example. Moreover, if the pipeline layout scheme is changed, the comparative example needs to modify the inner tube model first, then modify the outer tube model, and then modify the correlation, while the embodiment only needs to modify the equivalent model once. At the same time, it can be seen from Tables 1 and 2 that the stress analysis results at each node calculated by the scheme of the present invention have a smaller error than the results calculated by the prior art in the comparative example, which is within the error range allowed in industrial applications, proving that the scheme of the present invention has a higher accuracy in stress analysis.
[0076] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.
[0077] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.
[0078] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.
Claims
1. A method for analyzing the stress of a jacket pipe, characterized in that: The method comprises: S1: Calculate the equivalent outer diameter of the jacket according to formula (1): S2: Calculate the equivalent wall thickness d of the jacket according to formula (2): 当量 ; S3: Calculate the equivalent medium density σ of the jacket according to formula (3): 当量 ; S4: According to the model parameters of the jacket pipe, an analytical method is used to perform pipeline stress analysis and calculation, and the pipeline stress analysis results are calculated using CAESAR II software. The model parameters include the equivalent outer diameter of the jacket pipe. Equivalent wall thickness d 当量 and equivalent medium density σ 当量 ; in, d1 and σ1 are respectively the outer diameter, wall thickness and material density of the outer tube of the jacket tube; d2 and σ2 are respectively the outer diameter of the inner tube of the jacket tube, the wall thickness of the inner tube and the material density of the inner tube; σ f1 is the density of the medium between the outer tube and the inner tube of the jacket tube, σ f2 are respectively the densities of the medium inside the inner tube of the jacket tube.
2. The method according to claim 1, characterized in that The method further includes: before step S1, confirming whether the jacket tube meets the analysis conditions, and performing step S1 when the jacket tube meets the analysis conditions; the analysis conditions include: the length of the jacket tube is ≤6000mm, and the temperature difference between the tube walls of the outer tube and the inner tube is ≤50°C.
3. The method according to claim 1, characterized in that The method further includes: when the jacket pipe does not meet the analysis conditions, checking and calculating the weld strength of the jacket end plate or the jacket flange of the jacket pipe until the weld strength meets the allowable stress requirement of the pipe in the ASME Pressure Piping Code B31.
3.
4. The method according to claim 1, characterized in that: The model parameters in step S4 also include: the design temperature T of the jacket pipe d , calculate the temperature T c and one or more of the material parameters ε of the jacket tube.
5. The method according to claim 4, characterized in that According to formula (4), T d , calculate T according to formula (5) c , calculate ε according to formula (6); T d =T d1 Formula (4) T c =T c1 Formula (5) ε=ε1 Formula (6); Among them, T d1 is the design temperature of the outer tube of the jacket tube, T c1 is the operating temperature of the outer tube of the jacketed tube, and ε1 is the material parameter of the outer tube of the jacketed tube.
6. The method according to claim 4, characterized in that The material parameters include one or more of pipe density, allowable stress and thermal expansion coefficient.
7. The method according to claim 1, characterized in that The outer tube of the jacketed tube is made of carbon steel or alloy steel, and the inner tube is made of the same or similar material as the outer tube.
8. The method according to any one of claims 1 to 7, characterized in that: The analyzing the stress of the jacket pipe includes: analyzing one or more of the load of the support frame of the jacket pipe, the primary stress and the secondary stress of the jacket pipe, and the force on the nozzle of the connected equipment.
9. The method according to any one of claims 1 to 7, characterized in that: The jacketed pipe is a jacketed pipe with a hidden inner pipe weld or a semi-jacketed pipe with an exposed inner pipe weld.