A welding method for a hydrogenation reactor support platform

Abstract

This invention relates to the field of welding and manufacturing of support platforms for hydrogenation reactors, specifically disclosing a welding method for such platforms. The method includes the following steps: creating stress grooves on the inner wall of the hydrogenation reactor, the stress grooves being adapted to the welding end face of the support platform; placing the welding end face of the support platform within the stress grooves; preheating the hydrogenation reactor; depositing a base layer in the gaps of the stress grooves around the welding end face and performing a hydrogen removal tempering heat treatment; preheating the hydrogenation reactor again; depositing a transition layer on the base layer and performing a hydrogen removal heat treatment; and depositing a corrosion-resistant layer on the transition layer. This invention proposes a welding method that, by processing stress grooves before depositing the support platform and employing two heat treatment processes for different deposit layers, effectively controls the residual welding stress and deformation of the support platform, improving the microstructure and effectively solving the problems of high welding stress and deformation, and coarse grains in the support platform of the hydrogenation reactor.

Description

Technical Field

[0001] This invention relates to the field of welding and manufacturing of hydrogenation reactor support platforms, and more specifically to a welding method for hydrogenation reactor support platforms. Background Technology

[0002] Hydrogenation reactors are crucial equipment in the petrochemical industry, used for hydrocracking and hydrorefining. They are commonly used to hydrogenate the most difficult-to-utilize heavy components of the petroleum industry—residue oil—into light oils, ultimately producing gasoline, diesel, and other products. They hold a vital position in petrochemical production. With the development of the petrochemical industry, hydrogenation reactors are evolving towards higher internal pressure and larger sizes. Due to process requirements, the inner wall of the hydrogenation reactor shell contains numerous support platforms to house the cooling hydrogen trays, injection trays, catalyst support trays, and other internal components. However, these support platforms cannot be integrally formed with the shell; they must be constructed by welding the shell material. This not only results in a complex structure and a long manufacturing cycle (up to one month), but also leads to significant residual stress and deformation from welding, uneven microstructure after welding, coarse grains, and a tendency to crack. This represents the "high ground" of hydrogenation reactor manufacturing technology.

[0003] Existing methods for welding support platforms mainly focus on improving welding efficiency through welding methods or enhancing welding quality through welding processes or post-weld heat treatment. However, these methods do not comprehensively consider all control factors and lack a welding manufacturing method that simultaneously controls the stress, deformation, and microstructure of the support platform. Therefore, it is necessary to propose a method that takes into account the welding process, heat treatment process, deformation, and microstructure control in order to achieve simultaneous control of stress, deformation, and microstructure during the welding manufacturing process of the support platform.

[0004] Based on this technical background, the present invention studies a welding method for a hydrogenation reactor support platform. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a welding method for a hydrogenation reactor support platform. By processing stress grooves before welding the support platform and employing two heat treatment processes for different weld overlay layers, the residual welding stress and deformation of the support platform are effectively controlled, and the microstructure is improved. This effectively solves the problems of high welding stress and deformation, and coarse grains in the support platform of the hydrogenation reactor.

[0006] To achieve the above objectives, the present invention provides a welding method for a hydrogenation reactor support platform, the method comprising the following steps:

[0007] A stress groove is formed on the inner wall of the hydrogenation reactor. The stress groove is adapted to the welding end face of the support platform, and the welding end face of the support platform is placed in the stress groove.

[0008] The hydrogenation reactor is preheated, and the base layer is deposited in the stress groove gaps around the welded end face and subjected to hydrogen removal tempering heat treatment.

[0009] The hydrogenation reactor is preheated again, and a transition layer is welded onto the base layer before hydrogen removal heat treatment is performed.

[0010] A corrosion-resistant layer is deposited on the transition layer.

[0011] The effects of this invention are:

[0012] (1) The welding method for the support platform of the hydrogenation reactor proposed in this invention effectively controls the welding residual stress and deformation of the support platform by opening stress grooves before welding the support platform and taking two heat treatment processes for different weld layers. The microstructure is also improved, which effectively solves the problems of large welding stress and deformation and coarse grains on the support platform of the hydrogenation reactor.

[0013] (2) The welding method for the support platform of the hydrogenation reactor proposed in this invention ensures that the root of the support platform is the base material by opening stress grooves on the inner wall of the hydrogenation reactor, and the stress concentration is transferred to the base material, avoiding stress concentration in the weld, effectively improving the stress condition of the weld. At the same time, by grinding and removing the excess and deformation of the base layer and the hydrogenation reactor cylinder, the residual welding stress is reduced by 45%.

[0014] (3) The welding method for the support platform of the hydrogenation reactor proposed in this invention determines the heat input of the base layer, the heat input of the transition layer and the heat input of the corrosion-resistant layer by simulating and analyzing the relationship between the deformation of the hydrogenation reactor cylinder with different wall thicknesses, the temperature difference between the inner and outer walls and the heat input during the welding process, so that the heat input range of different layers can be effectively controlled.

[0015] (4) The welding method for the hydrogenation reactor support platform proposed in this invention effectively controls the microstructure of the support platform by performing hydrogen removal tempering heat treatment on the weld overlay base layer and hydrogen removal heat treatment on the weld overlay transition layer, thereby refining the grain size and controlling the grain size to level 8.

[0016] (5) The hydrogenation reactor support platform welding method proposed in this invention determines the number of hydrogen removal and tempering heat treatments by simulating and analyzing the relationship between the residual stress field of the welded end face of the support platform with different widths and the number of heat treatments during the hydrogen removal and tempering heat treatment process, so that the hydrogen removal and tempering heat treatment process is precise and controllable.

[0017] (6) The welding method for the support platform of the hydrogenation reactor proposed in this invention realizes the integrated control of welding stress, deformation and microstructure of the support platform, and effectively solves the bottleneck problem of large welding stress and deformation and coarse grains on the support platform of the hydrogenation reactor.

[0018] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0020] Figure 1 This is a schematic diagram of the welding method for the hydrogenation reactor support platform proposed in this invention.

[0021] Figure 2A This is a top view schematic diagram of the stress groove structure and dimensional requirements in the welding method for the hydrogenation reactor support platform proposed in this invention.

[0022] Figure 2B This is a cross-sectional schematic diagram showing the stress groove structure and dimensional requirements in the welding method for the hydrogenation reactor support platform proposed in this invention.

[0023] Figure 2C This is a cross-sectional view of the weld joint after grinding and removing excess material and deformation of the base layer and the hydrogenation reactor cylinder in the welding method for the hydrogenation reactor support platform proposed in this invention.

[0024] Figure 3A This image shows a comparison of the effects of axial residual stress at the weld joint of the hydrogenation reactor support platform using traditional methods and the welding method proposed in this invention.

[0025] Figure 3B This image shows a comparison of the effects of circumferential residual stress at the weld joint of the hydrogenation reactor support platform using traditional methods and the welding method proposed in this invention.

[0026] Figure 4A This is a diagram showing the microstructure of the welded joint of the support platform using traditional methods.

[0027] Figure 4B This is a diagram showing the microstructure of the welded joint of the hydrogenation reactor support platform using the welding method proposed in this invention.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1-Stress tank, 2-Support platform, 3-Hydrogenation reactor. Detailed Implementation

[0030] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0031] In this invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its normal operating state, for example, as shown in the reference. Figure 1In the drawing orientation, "inner" and "outer" refer to those relative to the outline of the device. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] This invention provides a welding method for a hydrogenation reactor support platform, such as... Figure 1 , Figure 2A , Figure 2B and Figure 2C As shown, the method includes the following steps:

[0033] A stress groove 1 is opened on the inner wall of the hydrogenation reactor 3. The stress groove 1 is adapted to the welding end face of the support platform 2. The welding end face of the support platform 2 is placed in the stress groove 1.

[0034] The hydrogenation reactor 3 is preheated, and the base layer is built up in the gap of the stress groove 1 around the weld end face and subjected to hydrogen removal tempering heat treatment.

[0035] The hydrogenation reactor 3 is preheated again, and a transition layer is welded onto the base layer before hydrogen removal heat treatment is performed.

[0036] A corrosion-resistant layer is deposited on the transition layer.

[0037] In this invention, by opening a stress groove 1 before the weld overlay support platform 2 and taking two heat treatment processes for different weld overlay layers, the residual welding stress and deformation of the support platform 2 are effectively controlled, and the microstructure is also improved. This effectively solves the problems of large weld overlay stress and deformation and coarse grains on the support platform 2 of the hydrogenation reactor 3.

[0038] In this invention, by performing hydrogen removal tempering heat treatment on the weld overlay base layer and hydrogen removal heat treatment on the weld overlay transition layer, the microstructure of the support platform 2 is effectively controlled, and the grain size is refined and controlled at level 8.

[0039] According to the present invention, the dimensions of the stress groove 1 and the support platform 2 satisfy the following relationship:

[0040] σ1=σ2+2(8~10)mm;

[0041]

[0042] Where σ1 is the width of the stress groove, σ2 is the width of the welding end face of the support platform, d1 is the depth of the stress groove, and d2 is the height of the support platform.

[0043] According to the present invention, the heat input of the base layer, the heat input of the transition layer, and the heat input of the corrosion-resistant layer are determined before welding the base layer, before welding the transition layer, and before welding the corrosion-resistant layer, respectively.

[0044] The heat input of the base layer, the heat input of the transition layer, and the heat input of the corrosion-resistant layer were all determined through simulation analysis of the relationship between the deformation of the hydrogenation reactor 3 cylinder with different wall thicknesses, the temperature difference between the inner and outer walls, and the heat input during the welding process.

[0045] Preferably, when the wall thickness of the hydrogenation reactor 3 cylinder is 100-300mm, the heat input of the base layer is 20-25KJ / cm, the heat input of the transition layer is 15-20KJ / cm, and the heat input of the corrosion-resistant layer is 15-20KJ / cm.

[0046] When the wall thickness of the hydrogenation reactor shell is 300-400 mm, the heat input of the base layer is 25-30 KJ / cm, the heat input of the transition layer is 20-25 KJ / cm, and the heat input of the corrosion-resistant layer is 20-25 KJ / cm.

[0047] In this invention, the relationship between the deformation of the hydrogenation reactor 3 cylinder with different wall thicknesses, the temperature difference between the inner and outer walls and the heat input during the welding process is simulated and analyzed to determine the heat input of the base layer, the heat input of the transition layer and the heat input of the corrosion-resistant layer, so that the heat input range of different layers can be effectively controlled.

[0048] According to the present invention, the hydrogen removal and tempering heat treatment sequentially includes hydrogen removal, tempering, furnace cooling and air cooling;

[0049] The temperature for hydrogen removal is 250-350℃, and the time is 1-3 hours;

[0050] The heating rate for tempering is 40-60℃ / min, the final temperature is 550-650℃, and the time is 2-6 hours.

[0051] The furnace cooling temperature is 350-450℃;

[0052] The temperature of air cooling is 25-35℃.

[0053] According to the present invention, the number of hydrogen removal tempering heat treatments is determined before the hydrogen removal tempering heat treatment;

[0054] The number of hydrogen-removing tempering heat treatments was determined through simulation analysis of the relationship between the residual stress field and the number of heat treatments on the welding end face of the support platform 2 with different widths during the hydrogen-removing tempering heat treatment process.

[0055] Preferably, when the width of the welding end face of the support platform 2 is not greater than 60mm, a hydrogen removal tempering heat treatment is performed after the overlay welding base layer is completed;

[0056] When the width of the welding end face of the support platform 2 is 60mm-90mm, a hydrogen removal tempering heat treatment is performed once when the base layer is 1 / 2 thick and once after completion.

[0057] When the width of the welding end face of the support platform 2 is not less than 100mm, a hydrogen removal tempering heat treatment shall be performed when the base layer is 1 / 3 thick, 2 / 3 thick, and after completion.

[0058] In this invention, the number of hydrogen-removing tempering heat treatments is determined by simulating and analyzing the relationship between the residual stress field of the welded end face of the support platform 2 with different widths and the number of heat treatments during the hydrogen removal tempering heat treatment process, so that the hydrogen removal tempering heat treatment process is precise and controllable.

[0059] According to the present invention, after the hydrogen removal tempering heat treatment, the base layer and the remaining material and deformation of the hydrogenation reactor 3 cylinder are polished and removed.

[0060] In this invention, by opening stress grooves 1 on the inner wall of the hydrogenation reactor 3, the root of the support platform 2 is made of the base material, and the stress concentration is transferred to the base material, avoiding stress concentration in the weld and effectively improving the stress condition of the weld. At the same time, by grinding and removing the excess and deformation of the base layer and the cylinder of the hydrogenation reactor 3, the residual welding stress is reduced by 45%.

[0061] Preferably, the hydrogen removal heat treatment includes hydrogen removal and air cooling in sequence;

[0062] The temperature for hydrogen removal is 250-350℃, and the time is 1-3 hours;

[0063] The temperature of air cooling is 25-35℃.

[0064] Preferably, the preheating temperature is 100-200℃;

[0065] The reheating temperature is 100-200℃;

[0066] During the welding process, the temperature difference between any two layers in the base layer, transition layer, and corrosion-resistant layer shall not exceed 250℃.

[0067] The method in this invention achieves integrated control of welding stress, deformation, and microstructure of the support platform, effectively solving the bottleneck problems of large welding stress and deformation, and coarse grains on the support platform of the hydrogenation reactor 3.

[0068] The present invention will now be described in more detail through a specific embodiment.

[0069] Example 1

[0070] This embodiment provides a welding method for a support platform of a hydrogenation reactor. In this embodiment, the reactor body 3 is made of 12Cr-2Mo-1V material with a wall thickness of 320mm. The welding end face of the support platform 2 has a width of 80mm and a height of 60mm. Figure 1 , Figure 2A , Figure 2B and Figure 2C As shown, the method includes the following steps:

[0071] A stress groove 1 is opened on the inner wall of the hydrogenation reactor 3. The stress groove 1 is 100mm wide and 20mm high. The welding end face of the support platform 2 is placed in the stress groove 1.

[0072] The hydrogenation reactor is preheated to 3 to 150°C with a heat input of 27 KJ / cm. The base layer is welded in the stress tank 1 using electroslag welding technology. When the base layer is welded to a thickness of 7.5 mm, a heat treatment is performed. When the thickness is 15 mm, a second heat treatment is performed. The heat treatment process is as follows: hydrogen removal heat treatment is performed at 300°C and held for 2 hours. Then, the temperature is increased to 620°C at 50°C / min for tempering heat treatment and held for 3 hours. After that, the furnace is cooled to 400°C and then air-cooled to 30°C.

[0073] After the base layer is heat-treated, the excess material of the base layer and cylinder is removed by machining and grinding to eliminate the deformation of the base layer and cylinder.

[0074] The hydrogenation reactor was preheated again to 3 to 150°C with a heat input of 22 KJ / cm. After a transition layer was welded onto the base layer, the reactor was subjected to hydrogen removal heat treatment at 300°C for 2 hours, followed by air cooling.

[0075] A corrosion-resistant layer is directly welded onto the transition layer using a heat input of 22KJ / cm.

[0076] Each layer of welding should be performed continuously and completed in one go, without interruption; at the same time, the temperature difference between each layer should not exceed 250℃.

[0077] As can be seen from the above comparison, the welding method for the support platform of the hydrogenation reactor provided in this embodiment effectively controls the welding residual stress and deformation of the support platform 2, and improves the microstructure, refines the grains, and controls the grain size to about level 8. It realizes the integrated control of welding stress-deformation-microstructure of the support platform 2, and effectively solves the problems of large welding stress and deformation and coarse grains of the support platform 2 on the hydrogenation reactor 3.

[0078] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A welding method for a hydrogenation reactor support platform, characterized in that, The method includes the following steps: A stress groove is formed on the inner wall of the hydrogenation reactor. The stress groove is adapted to the welding end face of the support platform, and the welding end face of the support platform is placed in the stress groove. The hydrogenation reactor is preheated, and the base layer is deposited in the stress groove gaps around the welded end face and subjected to hydrogen removal tempering heat treatment. The hydrogenation reactor is preheated again, and a transition layer is welded onto the base layer before hydrogen removal heat treatment is performed. A corrosion-resistant layer is deposited on the transition layer; The dimensions of the stress groove and the support platform satisfy the following relationship: ； in, The width of the stress groove, To support the width of the welding end face of the platform, For the depth of the stress groove, To support the height of the platform; Before welding the base layer, before welding the transition layer, and before welding the corrosion-resistant layer, the heat input of the base layer, the heat input of the transition layer, and the heat input of the corrosion-resistant layer are determined respectively. The heat input of the base layer, the heat input of the transition layer, and the heat input of the corrosion-resistant layer were all determined by simulation analysis of the relationship between the deformation of the hydrogenation reactor shell with different wall thicknesses, the temperature difference between the inner and outer walls, and the heat input during the welding process. When the wall thickness of the hydrogenation reactor shell is 100-300mm, the heat input of the base layer is 20-25KJ / cm, the heat input of the transition layer is 15-20KJ / cm, and the heat input of the corrosion-resistant layer is 15-20KJ / cm. When the wall thickness of the hydrogenation reactor shell is 300-400 mm, the heat input of the base layer is 25-30 KJ / cm, the heat input of the transition layer is 20-25 KJ / cm, and the heat input of the corrosion-resistant layer is 20-25 KJ / cm. The hydrogen removal and tempering heat treatment includes hydrogen removal, tempering, furnace cooling and air cooling in sequence. The hydrogen removal temperature is 250-350℃, and the time is 1-3 hours; The tempering process has a heating rate of 40-60℃ / min, a final temperature of 550-650℃, and a duration of 2-6 hours. The furnace cooling temperature is 350-450℃; The temperature of the air cooler is 25-35℃; The hydrogen removal heat treatment includes hydrogen removal and air cooling in sequence; The hydrogen removal temperature is 250-350℃, and the time is 1-3 hours; The air-cooled temperature is 25-35℃.

2. The method according to claim 1, characterized in that, The number of hydrogen removal tempering heat treatments is determined before the hydrogen removal tempering heat treatment; The number of hydrogen-removing tempering heat treatments was determined by simulation analysis of the relationship between the residual stress field of the welded end face of the support platform with different widths and the number of heat treatments during the hydrogen-removing tempering heat treatment process.

3. The method according to claim 2, characterized in that, When the width of the welded end face of the support platform is not greater than 60mm, a hydrogen removal tempering heat treatment shall be performed after the overlay welding base layer is completed. When the width of the welding end face of the support platform is 60mm-90mm, a hydrogen removal tempering heat treatment is performed once when the base layer is 1 / 2 thick and once after completion. When the width of the welded end face of the support platform is not less than 100mm, a hydrogen removal tempering heat treatment shall be performed when the base layer is 1 / 3 thick, 2 / 3 thick, and after completion.

4. The method according to claim 1, characterized in that, After the hydrogen removal and tempering heat treatment, the base layer and the hydrogenation reactor cylinder are ground and the excess and deformation are removed.

5. The method according to claim 1, characterized in that, The preheating temperature is 100-200℃; The reheating temperature is 100-200℃; During the welding process, the temperature difference between any two of the base layer, transition layer and corrosion-resistant layer shall not exceed 250°C.

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