Overall evaluation method for normal-pressure storage tank containing defect

An atmospheric storage tank and evaluation method technology, applied in special data processing applications, instruments, electrical digital data processing, etc. The effect of crack propagation and high reliability

Inactive Publication Date: 2018-08-03
SPECIAL EQUIP SAFETY SUPERVISION INSPECTION INST OF JIANGSU PROVINCE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] NB / T47013 "Nondestructive Testing of Pressure Equipment" only discusses the method and process of defect detection means, and does not calculate the local force of the defect, but classifies the defect according to the size of the defect, but even RT detection Class IV defects or class II defects of PT and MT do not necessarily affect the use of storage tanks
At the same time, the defect grading object of NB / T47013 "Nondestructive Testing of Pressure Equipment" is pressure equipment, which is not completely applicable to storage tanks.
Depending on the construction quality of the storage tank, there will be more or less several or dozens of defects. In this case, if all the defects are identified as unqualified, the repair work will be very cumbersome, which will greatly affect the enterprise. At the same time, in the repair process, once the number of defects is large, it may be due to various reasons such as welding process, welder level, welding residual stress interaction among multiple defects, etc., resulting in the tank repair effect is often not as good satisfactory

Method used

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  • Overall evaluation method for normal-pressure storage tank containing defect
  • Overall evaluation method for normal-pressure storage tank containing defect
  • Overall evaluation method for normal-pressure storage tank containing defect

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0075] Stability analysis when 1 / 3 of the second layer weld at the bottom of the oil storage tank is not penetrated, the specific analysis is as follows: import the model into ANSYS Workbench, and when 1 / 3 of the weld at the bottom of the oil storage tank cracks, the oil storage tank The contact between the second layer of the tank model is set to 2 / 3 of the contact surface binding, and a fixed constraint is added at the bottom of the tank; gravity is applied to the tank model; wind load is applied to the tank model; the solution is obtained Stress results after linear buckling of the oil storage tank, such as figure 2 As shown, the linear buckling stress results obtained by solving, the graph area shows that the buckling load factor is only 0.49413. Therefore, when 1 / 3 of the second-layer weld at the bottom of the oil storage tank is not penetrated, the oil storage tank will be unstable under the action of wind load and gravity.

Embodiment 2

[0077] Stability analysis when 1 / 3 of the second-layer weld at the bottom of the oil storage tank is not penetrated (cracks are discontinuous), the specific analysis is as follows: When 1 / 3 of the weld is cracked and the crack is discontinuous (assuming that the weld has two cracks , and the weld cracks are all 1 / 6); when the model is imported into ANSYS Workbench, when 1 / 3 of the weld cracks are found on the second layer of the bottom of the oil storage tank and the weld cracks are discontinuous, the second layer of the bottom layer of the oil storage tank model The contact between them is set to 2 / 3 binding, and a fixed constraint is added to the oil storage tank model and a load is applied; the solution is obtained to obtain the stress result of the oil storage tank after linear buckling, such as image 3 As shown, the result obtained by solving the linear buckling stress, the graph area shows the buckling load factor is 1.5563. Therefore, when 1 / 3 of the second-layer weld ...

Embodiment 3

[0079] Stability analysis when 1 / 2 of the second layer weld at the bottom of the oil storage tank is not penetrated, the specific analysis is as follows: import the model into ANSYS Workbench, and when 1 / 2 of the weld at the bottom of the oil storage tank cracks, the oil storage tank The contact between the second layer of the tank model is set to 1 / 2 of the contact surface binding, and a fixed constraint is added at the bottom of the tank; gravity is applied to the tank model; wind load is applied to the tank model; the solution is obtained Stress results after linear buckling of the oil storage tank, such as Figure 4 shown; obtained by solving the linear buckling stress results, the graph area shows that the buckling load factor is 0.1391. Therefore, when 1 / 2 of the second-layer weld at the bottom of the oil storage tank is not penetrated, the oil storage tank will be unstable under the action of wind load and gravity.

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Abstract

The invention discloses an overall evaluation method for a normal-pressure storage tank containing a defect. The method is characterized by including the following steps: measuring a property, a sizeand a position of the defect on the storage tank; establishing a storage tank model of the defect in Ansys software according to a storage tank structure and the defect position, size and property; using the Ansys software for loading actual loads to calculate storage tank structure strength and a storage tank stress strength factor, and loading unit loads for stability calculation; and evaluatingcalculated and obtained storage tank structure strength, the storage tank stress strength factor and a stability result to comprehensively evaluate safety status of the storage tank. According to themethod, deficiencies and shortcomings on the aspect of current domestic storage tank safety evaluation standards are solved, the safety status of the storage tank is evaluated from multiple angles ofstructural mechanics, fracture mechanics and the like through a method of combining non-destructive earlier-stage detection and calculation of the finite-element software Ansys, and a calculation result has higher reliability.

Description

technical field [0001] The invention relates to the technical field of petrochemical equipment, in particular to an overall evaluation method for an atmospheric storage tank with defects. Background technique [0002] my country's storage tank inspection work is carried out relatively late, and a complete set of storage tank inspection standards has not yet been formed. my country built a large number of petrochemical storage tanks in the 1980s and 1990s. Due to the lack of regulations and standards at that time, the construction quality of many storage tanks was not ideal, and there were usually many defects inside. At present, there is no safety evaluation method dedicated to storage tank defects in China. If the defects of storage tanks are to be qualitatively and quantitatively determined, the method of combining RT (ray) flaw detection with PT (magnetic particle) flaw detection or MT (penetration) flaw detection is generally used. Defect grading refers to NB / T47013 "No...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F30/367
Inventor 宋高峰吴航张延兵张诚孙志涛王玉林刘功祥黄佳俊徐中原胡军
Owner SPECIAL EQUIP SAFETY SUPERVISION INSPECTION INST OF JIANGSU PROVINCE
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