A method for repairing welded joints of pressure swing adsorber under hydrogen-rich alternating load

Abstract

The present invention provides a method for repairing a welded joint of a pressure swing adsorber under hydrogen-rich alternating load, with the maximum fatigue limit as the target, and the optimal residual stress matching value of the repaired part is obtained through the Goodman relationship; based on the inherent strain of the cladding metal at the repaired part, the relationship between the temperature load, the thermal expansion coefficient and the strain of the cladding metal at the repaired part ε=W / F=α·ΔT is established to obtain the repair heat input and cladding amount required for the optimal residual stress matching value; the repair process is simulated by using SYSWELD software, and the geometric contour of the repaired part and the repair process parameters are verified by finite element simulation to obtain the optimal scheme of the geometric contour and process of the part to be repaired; laser or electric arc is used as the heat source, and the geometric modeling of the part to be repaired, the path planning of the welding robot, and the parameter setting of the repair process are completed to complete the automatic programming, that is, the repair of the welded joint of the pressure swing adsorber under hydrogen-rich alternating load is completed. The present invention improves the operating efficiency and safety, and ensures the long-term safe operation of the equipment and social security.

Description

Technical Field

[0001] The invention relates to the technical field of welding joint repair, and in particular to a method for repairing a welding joint of a pressure swing adsorber under hydrogen-rich alternating load. Background Art

[0002] Pressure swing adsorption device is a kind of core pressure vessel equipment in the coal chemical production process. Its principle is to use the adsorption characteristics of different gas components of the adsorbent that change with pressure. Through the principle of high-pressure adsorption and low-pressure analysis of the adsorbent, the single gas in the mixed gas is separated by alternating high and low pressures to achieve the separation and purification of flammable and explosive gases. The pressure swing adsorber works under complex working conditions such as high temperature, high pressure and alternating load for a long time. The fatigue failure of the equipment will cause significant losses to the society and the country. The safety of adsorption equipment has gradually become one of the major issues of safety management.

[0003] Strength damage or fracture caused by fatigue damage is as high as 50% to 90%. According to statistics, more than 75% of the damage to pressure vessels is caused by fatigue damage, which is the main failure mode of pressure vessels and will cause serious economic losses and casualties. For this reason, the safety technology assessment and timely repair of pressure vessels have always been the core issues of concern to the industry.

[0004] By consulting relevant information and the summary of the inspection results of multiple pressure swing adsorbers of a coal chemical enterprise in Ningdong by the Ningxia Special Equipment Inspection and Testing Institute, the main failure mode of adsorbers in the coal chemical industry is fatigue failure mode at the weld, which leads to various unexpected cracking, bulging and other failure problems in the pressure swing adsorption devices used. Since the pressure swing adsorption device is located upstream of the production process, if a certain device fails and causes gas leakage, it is easy to cause a special equipment safety accident when encountering an open flame, and the consequences and losses are immeasurable. At the same time, it causes insufficient supply of upstream raw gas, which will lead to a reduction in production or shutdown of the entire production chain. The indirect economic losses are more than 10 million, which is not conducive to social security and the safety of people's lives and property, and invisibly increases the direct costs of enterprises. Through the early detection and prediction of the pressure swing adsorption equipment in use, timely repair of the welds in advance is conducive to improving the operating efficiency and safety of the pressure swing adsorption device, reducing equipment failures and downtime, reducing production costs, and ensuring the long-term safe operation of the equipment and social security. Summary of the invention

[0005] Based on the above background technology, the purpose of the present invention is to provide a method for repairing a welded joint of a pressure swing adsorber under hydrogen-rich alternating load.

[0006] The present invention adopts the following technical solutions:

[0007] A method for repairing a welded joint of a pressure swing adsorber under hydrogen-rich alternating load, comprising the following steps:

[0008] (1) Using nondestructive testing methods, the spatial distribution of pores and microcracks in the welded joints to be repaired in the adsorber is obtained;

[0009] Furthermore, the non-destructive testing methods in step (1) are X-ray and ultrasonic.

[0010] In the above technical solution, the spatial distribution position of defects such as pores and microcracks refers to the size and distribution position of defects such as pores and microcracks.

[0011] (2) Using X-rays to obtain the residual stress of the welded joint to be repaired, and extracting the peak and average values ​​of the axial and radial residual stresses;

[0012] (3) Use a hydrogen analyzer to measure the hydrogen content of the welded joint to be repaired online;

[0013] Furthermore, when the hydrogen content is measured online in step (3), the measurement range is: 0-2% / 100%; resolution: 0.1% / 0.01%; measurement accuracy: ≤±2%FS; repeatability: ≤±1%FS; ambient temperature: -5°C to +45°C; ambient humidity: ≤90%RH.

[0014] (4) The hydrogen content of the welded joint to be repaired is converted into the volume of diffusible hydrogen per 100g of deposited metal under standard conditions, in units of mL / 100g; local dehydrogenation treatment is performed according to the hydrogen content of the welded joint to be repaired, at a temperature of 200 to 300°C for 0.5 to 1 hour;

[0015] In the above technical solution, the standard state is 0°C and 101 325Pa atmospheric pressure.

[0016] (5) The peak value and average value of the residual stress of the welded joint to be repaired obtained in step (2) are introduced to optimize the stress matching of the residual stress of the repaired part based on the service condition of the repaired part; the stress matching optimization rule adopts the influence of the average stress on the fatigue limit and is described by the Goodman relationship:

[0017]

[0018] Among them, σ m is the mean stress, σ b is the tensile strength, is m = 0 when fatigue limit; there is σ m Fatigue limit

[0019] Furthermore, the service conditions of the part to be repaired in step (5) include temperature, load and vibration frequency.

[0020] (6) Based on the inherent strain of the cladding metal at the repaired part, according to the given unit temperature load and the value of the thermal expansion coefficient α, the numerical change relationship of the strain ε of the cladding metal at the repaired part is obtained: ε=W / F=α·ΔT; secondly, according to the spatial distribution position of the defect in step (1), the repair heat input and cladding amount required for the optimal stress matching value in step (5) are obtained;

[0021] (7) According to the peak value and average value of the residual stress of the original weld joint to be repaired obtained in step (2), and the repair heat input and cladding amount obtained in step (6), the repair process is simulated using SYSWELD software, and the geometric profile and repair process parameters of the repaired part are simulated and verified by finite element method to obtain the optimal solution of the geometric profile and process of the repaired part;

[0022] Furthermore, the repair process parameters in step (7) include laser power, wire feeding speed and protective gas flow rate.

[0023] (8) Using the preferred process parameters obtained in step (7), laser or arc is used as the heat source, and 0.6-1.6 mm homogeneous wire is selected as the filling material to automatically program the repair process. The automated programming includes geometric modeling of the part to be repaired, welding robot path planning, and repair parameter setting, thereby completing the repair of the pressure swing adsorber welding joint under hydrogen-rich alternating load.

[0024] Furthermore, the repair parameter settings in step (8) include settings such as laser power, wire feed speed, and shielding gas flow rate. Furthermore, it also includes induction of local heat treatment of the repaired part, and the value of the post-heating temperature is: Tp = 455.5 [Ceq] p - 111.4 where Tp is the post-heating temperature °C; [Ceq] p is the carbon equivalent formula;

[0025] [Ceq]p=C+0.2033Mn+0.0473Cr+0.1228Mo+0.0292Ni+0.0359Cu+0.0792Si-1.595P+1.692S+0.844V.

[0026] The present invention has the following beneficial effects:

[0027] Taking the maximum fatigue limit as the goal, the Goodman relationship is used to obtain the optimal residual stress matching value of the repaired part; based on the inherent strain of the cladding metal in the repaired part, the relationship between temperature load, thermal expansion coefficient and strain of the cladding metal in the repaired part ε=W / F=α·ΔT is established; the repair heat input and cladding amount required for the optimal residual stress matching value are obtained; the SYSWELD software is used to simulate the repair process, and the finite element simulation verification is performed on the geometric contour of the repaired part and the repair process parameters to obtain the optimal solution for the geometric contour and process of the repaired part; laser or arc is used as the heat source, and the geometric modeling of the repaired part, welding robot path planning, and parameter setting are performed to complete the automated programming of the repair process, that is, the repair of the pressure swing adsorber welding joint under hydrogen-rich alternating load is completed.

[0028] The present invention improves the operating efficiency and safety of the pressure swing adsorption device, reduces equipment failures and downtime, reduces production costs, and ensures long-term safe operation of the equipment and social security by early detection and prediction of the pressure swing adsorption equipment in use and timely repairs the welds in advance. DETAILED DESCRIPTION

[0029] The present invention is specifically described below in conjunction with specific embodiments:

[0030] As one embodiment thereof, a method for repairing a welded joint of a pressure swing adsorber under hydrogen-rich alternating load comprises the following steps:

[0031] (1) Use nondestructive testing methods such as X-ray and ultrasonic to obtain information such as the spatial distribution of defects such as pores and microcracks in the welded joints to be repaired in the adsorber;

[0032] (2) Using X-rays to obtain the residual stress of the welded joint to be repaired, and extracting the peak and average values ​​of the axial and radial residual stresses;

[0033] (3) Use a hydrogen analyzer to measure the hydrogen content of the welded joint to be repaired online;

[0034] Measuring range: 0-2% / 100%; resolution: 0.1% / 0.01%; measuring accuracy: ≤±2%FS; repeatability: ≤±1%FS; ambient temperature: -5℃~+45℃; ambient humidity: ≤90%RH.

[0035] (4) The hydrogen content of the welded joint to be repaired is converted into the volume of diffusible hydrogen per 100g of deposited metal under standard conditions (0°C, 101 325Pa atmospheric pressure), with the unit of mL / l00g; local dehydrogenation treatment is performed according to the hydrogen content of the welded joint to be repaired, at a temperature of 200-300°C for 0.5-1 hour;

[0036] (5) The peak value and average value of the residual stress of the welded joint to be repaired obtained in step (2) are introduced, and the residual stress of the repaired part is optimized based on the service conditions (temperature, load, vibration frequency, etc.) of the repaired part. The stress matching optimization rule adopts the influence of the average stress on the fatigue limit and is described by the Goodman relationship:

[0037]

[0038] Among them, σ m is the mean stress, σ b is the tensile strength, is m = 0 when fatigue limit; there is σ m Fatigue limit

[0039] (6) Based on the inherent strain of the cladding metal at the repaired part, according to the given unit temperature load and the value of the thermal expansion coefficient α, the numerical change relationship of the strain ε of the cladding metal at the repaired part is obtained: ε=W / F=α·ΔT; secondly, according to the spatial distribution position of the defect in step (1), the repair heat input and cladding amount required for the optimal stress matching value in step (5) are obtained;

[0040] (7) According to the peak value and average value of the residual stress of the original weld joint to be repaired obtained in step (2), and the repair heat input and cladding amount obtained in step (6), the repair process is simulated using SYSWELD software, and the geometric profile of the repaired part and the repair process parameters (laser power, wire feeding speed and shielding gas flow rate, etc.) are simulated and verified by finite element method to obtain the optimal solution of the geometric profile and process of the repaired part;

[0041] (8) Using the preferred process parameters obtained in step (7), laser or arc is used as the heat source, and 0.6-1.6 mm homogeneous wire is selected as the filling material to automatically program the repair process, wherein the automated programming includes geometric modeling of the part to be repaired, path planning of the welding robot, and setting of repair parameters (such as laser power, wire feeding speed, and shielding gas flow rate);

[0042] (9) Induction local heat treatment of the repaired part, the post-heating temperature value is: Tp = 455.5 [Ceq] p-111.4

[0043] Where Tp is the post-heating temperature ℃; [Ceq]p is the carbon equivalent formula;

[0044] [Ceq]p=C+0.2033Mn+0.0473Cr+0.1228Mo+0.0292Ni+0.0359Cu+0.0792Si-1.595P+1.692S+0.844V.

[0045] That is, the repair of the welding joint of the pressure swing adsorber under hydrogen-rich alternating load is completed.

[0046] The maximum fatigue limit is taken as the target, and the optimal residual stress matching value of the repaired part is obtained through the Goodman relationship; based on the inherent strain of the cladding metal in the repaired part, the relationship between temperature load, thermal expansion coefficient and strain of the cladding metal in the repaired part ε=W / F=α·ΔT is established; the repair heat input and cladding amount required for the optimal residual stress matching value are obtained; the SYSWELD software is used to simulate the repair process, and the geometric contour of the repaired part and the repair process parameters are verified by finite element simulation to obtain the optimal solution for the geometric contour and process of the repaired part; laser or arc is used as the heat source, and the repair process is completed by geometric modeling of the repaired part, path planning of the welding robot, and parameter setting to complete the automatic programming, that is, to complete the repair of the welded joint of the pressure swing adsorber under hydrogen-rich alternating load. By early detection and prediction of the pressure swing adsorption equipment in use, the welds are repaired in time, which improves the operating efficiency and safety of the pressure swing adsorption device, reduces equipment failures and downtime, reduces production costs, and ensures the long-term safe operation of the equipment and social security.

[0047] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for repairing a welded joint of a pressure swing adsorber under hydrogen-rich alternating load, characterized in that: The following steps are involved: (1) Using nondestructive testing methods, the spatial distribution of pores and microcracks in the welded joints to be repaired in the adsorber is obtained; (2) Use a portable X-ray stress analyzer or resistance strain method to obtain the residual stress of the weld joint to be repaired, and extract the peak and average values ​​of the axial and radial residual stresses; (3) Use a hydrogen analyzer to measure the hydrogen content of the welded joint to be repaired online; (4) The hydrogen content of the welded joint to be repaired is converted into the volume of diffusible hydrogen per 100g of deposited metal under standard conditions, in units of mL / 100g; local dehydrogenation treatment is performed according to the hydrogen content of the welded joint to be repaired, at a temperature of 200 to 300°C for 0.5 to 1 hour; (5) The peak value and average value of the residual stress of the welded joint to be repaired obtained in step (2) are introduced to optimize the stress matching of the residual stress of the repaired part based on the service condition of the repaired part; the stress matching optimization rule adopts the influence of the average stress on the fatigue limit and is described by the Goodman relationship: Among them, σ m is the mean stress, σ b is the tensile strength, is m = 0 when fatigue limit; there is σ m Fatigue limit (6) Based on the inherent strain of the cladding metal at the repaired part, according to the given unit temperature load and the value of the thermal expansion coefficient α, the numerical change relationship of the strain ε of the cladding metal at the repaired part is obtained: ε=W / F=α·ΔT; secondly, according to the spatial distribution position of the defect in step (1), the repair heat input and cladding amount required for the optimal stress matching value in step (5) are obtained; (7) According to the peak value and average value of the residual stress of the original weld joint to be repaired obtained in step (2), and the repair heat input and cladding amount obtained in step (6), the repair process is simulated using SYSWELD software, and the geometric profile and repair process parameters of the repaired part are simulated and verified by finite element method to obtain the optimal solution of the geometric profile and process of the repaired part; (8) Using the preferred process parameters obtained in step (7), laser or arc is used as the heat source, and 0.6-1.6 mm homogeneous wire is selected as the filling material to automatically program the repair process. The automated programming includes geometric modeling of the part to be repaired, welding robot path planning, and repair parameter setting, thereby completing the repair of the pressure swing adsorber welding joint under hydrogen-rich alternating load.

2. A method for repairing a welded joint of a pressure swing adsorber under hydrogen-rich alternating load according to claim 1, characterized in that: The non-destructive testing methods in step (1) are X-ray and ultrasonic.

3. The method for repairing a welded joint of a pressure swing adsorber under hydrogen-rich alternating load according to claim 1, characterized in that: When the hydrogen content is measured online in step (3), the measurement range is: 0-2% / 100%; Resolution: 0.1% / 0.01%; Measurement accuracy: ≤±2%FS; Repeatability: ≤±1%FS; Ambient temperature: -5℃~+45℃; Ambient humidity: ≤90%RH.

4. The method for repairing a welded joint of a pressure swing adsorber under hydrogen-rich alternating load according to claim 1, characterized in that: The service conditions of the part to be repaired in step (5) include temperature, load and vibration frequency.

5. The method for repairing a welded joint of a pressure swing adsorber under hydrogen-rich alternating load according to claim 1, characterized in that: The repair process parameters in step (7) include laser power, wire feeding speed and shielding gas flow rate.

6. The method for repairing a welded joint of a pressure swing adsorber under hydrogen-rich alternating load according to claim 1, characterized in that: The repair parameter settings in step (8) include laser power, wire feeding speed, and shielding gas flow settings.

7. The method for repairing a welded joint of a pressure swing adsorber under hydrogen-rich alternating load according to claim 1, characterized in that: It also includes induction local heat treatment of the repaired parts, and the value of the post-heating temperature is: Tp = 455.5 [Ceq] p-111.4 Where Tp is the post-heating temperature ℃; [Ceq]p is the carbon equivalent formula; [Ceq]p=C+0.2033Mn+0.0473Cr+0.1228Mo+0.0292Ni+0.0359Cu+0.0792Si-1.595P+1.692S+0.844V。

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