Welding method for hydrogenation reactor supporting table

Abstract

The invention relates to the field of welding and manufacturing of hydrogenation reactor supporting tables, and particularly discloses a hydrogenation reactor supporting table welding method which comprises the following steps that stress grooves are formed in the inner wall of a hydrogenation reactor, the stress grooves are matched with the welding end faces of the supporting tables, and the welding end faces of the supporting tables are placed in the stress grooves; preheating the hydrogenation reactor, surfacing a base layer in a stress groove gap at the periphery of the welding end surface, and performing dehydrogenation tempering heat treatment; preheating the hydrogenation reactor again, surfacing a transition layer on the base layer, and then performing dehydrogenation heat treatment; and surfacing a corrosion-resistant layer on the transition layer. According to the welding method, the stress groove is machined before the supporting table is subjected to surfacing welding, the two-time heat treatment technology is adopted for different surfacing welding layers, the welding residual stress and deformation of the supporting table are effectively regulated and controlled, the structure is improved, and the problems that the surfacing welding stress and deformation of the upper supporting table of the hydrogenation reactor are large, and crystal grains are coarse are effectively solved.

Description

Technical Field

[0001] The invention relates to the field of welding and manufacturing of a hydrogenation reactor support platform, and in particular to a welding method for a hydrogenation reactor support platform. Background Art

[0002] Hydrogenation reactor is an important equipment for hydrocracking and hydrorefining in the petrochemical industry. It is often used to convert the most difficult heavy part of the petroleum industry, the residual oil, into light oil by hydrogenation, and then produce gasoline, diesel, etc. It plays a very important role in petrochemical production. With the development of the petrochemical industry, hydrogenation reactors are also developing in the direction of high internal pressure and large-scale. Due to process requirements, the inner wall of the hydrogenation reactor shell contains a large number of support platforms, which are used to place the support structure of the tower plate internal parts such as the cold hydrogen plate, injection plate, and catalyst support plate. However, the support platform cannot be formed as a whole with the shell, and can only be made by surfacing the barrel material. Not only is the structure complex, the manufacturing cycle is long (up to 1 month), but the surfacing residual stress and deformation are large, the post-welding structure is uneven, the grains are coarse, and it is easy to cause cracking. It is the "high ground" of the entire hydrogenation reactor manufacturing technology.

[0003] The existing support platform welding manufacturing mostly improves welding efficiency from the perspective of welding methods, or improves welding quality from the perspective of welding process or post-weld heat treatment. The control factors considered are not comprehensive, and there is no set of welding manufacturing methods for synchronous regulation of support platform stress, deformation, and organization. It is necessary to propose a method that takes into account surfacing process, heat treatment process, deformation and organization control to achieve synchronous regulation of stress-deformation-organization in the support platform welding manufacturing process.

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

[0005] In view of the shortcomings of the prior art, the present invention proposes a welding method for a hydrogenation reactor support platform. By processing stress grooves before surfacing the support platform, two heat treatment processes are respectively adopted for different surfacing layers, thereby effectively regulating the welding residual stress and deformation of the support platform, and the organization is also improved, effectively solving the problems of large surfacing stress and deformation and coarse grains of the support platform on the hydrogenation reactor.

[0006] In order to achieve the above object, the present invention provides a method for welding a support platform of a hydrogenation reactor, wherein the method comprises the following steps:

[0007] A stress groove is provided on the inner wall of the hydrogenation reactor, wherein the stress groove is adapted to the welding end surface of the support platform, and the welding end surface of the support platform is placed in the stress groove;

[0008] Preheating the hydrogenation reactor, surfacing a base layer in the stress groove gap around the welding end face and performing dehydrogenation and tempering heat treatment;

[0009] preheating the hydrogenation reactor again, and performing a dehydrogenation heat treatment after surfacing a transition layer on the base layer;

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

[0011] The effects of the present invention are:

[0012] (1) The hydrogenation reactor support platform welding method proposed in the present invention effectively regulates the welding residual stress and deformation of the support platform by opening a stress groove before surfacing the support platform and adopting two heat treatment processes for different surfacing layers. The structure is also improved, effectively solving the problems of large surfacing stress and deformation and coarse grains of the support platform on the hydrogenation reactor.

[0013] (2) The hydrogenation reactor support platform welding method proposed in the present invention ensures that the root of the support platform is the base material by opening a stress groove on the inner wall of the hydrogenation reactor, and the stress concentration is transferred to the base material, thereby 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 hydrogenation reactor cylinder, the welding residual stress is reduced by 45%.

[0014] (3) The hydrogenation reactor support welding method proposed in the present invention determines the heat input of the base layer, the transition layer and 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 cladding process, so that the heat input range of different layers can be effectively controlled.

[0015] (4) The hydrogenation reactor support platform welding method proposed in the present invention effectively regulates the microstructure of the support platform and refines the grains, and controls the grain size to level 8 by performing dehydrogenation and tempering heat treatment on the cladding base layer and dehydrogenation heat treatment on the cladding transition layer.

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

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

[0018] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0020] Figure 1 The figure is a schematic flow chart of the hydrogenation reactor support platform welding method proposed in the present invention.

[0021] Figure 2A It is a top view schematic diagram of the stress groove structure and size requirements in the hydrogenation reactor support platform welding method proposed by the present invention.

[0022] Figure 2B It is a cross-sectional schematic diagram of the stress groove structure and size requirements in the hydrogenation reactor support platform welding method proposed by the present invention.

[0023] Figure 2C It is a cross-sectional schematic diagram of the welding part after grinding and removing the surplus and deformation of the base layer and the hydrogenation reactor cylinder in the hydrogenation reactor support platform welding method proposed by the present invention.

[0024] Figure 3A This is a comparison diagram of the axial residual stress effect at the support platform welding point of the hydrogenation reactor support platform using the traditional method and the welding method of the hydrogenation reactor support platform proposed by the present invention.

[0025] Figure 3B This is a comparison diagram of the circumferential residual stress effect at the support platform welding point using the traditional method and the hydrogenation reactor support platform welding method proposed in the present invention.

[0026] Figure 4A This is the effect diagram of the microstructure of the support platform welding using the traditional method.

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

[0028] Description of reference numerals:

[0029] 1-stress tank, 2-support platform, 3-hydrogenation reactor. DETAILED DESCRIPTION

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

[0031] In the present invention, unless otherwise specified, directional words such as "upper" and "lower" generally refer to the upper and lower parts of a device in normal use. Figure 1In the drawing direction, "inside" and "outside" refer to the outline of the device. In addition, the terms "first, second, third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first, second, third" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

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

[0033] A stress groove 1 is provided on the inner wall of the hydrogenation reactor 3, the stress groove 1 is adapted to the welding end surface of the support platform 2, and the welding end surface of the support platform 2 is placed in the stress groove 1;

[0034] Preheating the hydrogenation reactor 3, surfacing the base layer in the gap of the stress groove 1 around the welding end face and performing dehydrogenation and tempering heat treatment;

[0035] Preheating the hydrogenation reactor 3 again, and performing a dehydrogenation heat treatment after surfacing a transition layer on the base layer;

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

[0037] In the present invention, by opening a stress groove 1 before surfacing the support platform 2, two heat treatment processes are respectively adopted for different surfacing layers, so as to effectively control the welding residual stress and deformation of the support platform 2, and improve the structure, thereby effectively solving the problems of large surfacing stress and deformation and coarse grains of the support platform 2 on the hydrogenation reactor 3.

[0038] In the present invention, by performing dehydrogenation tempering heat treatment on the cladding base layer and dehydrogenation heat treatment on the cladding transition layer, the structure morphology of the support platform 2 is effectively regulated, and the grains are refined, and the grain size is 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] Among them, 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 respectively before surfacing welding the base layer, before surfacing welding the transition layer and before surfacing welding the corrosion-resistant layer;

[0044] The heat input of the base layer, the transition layer and the corrosion resistant layer are determined by simulating and analyzing the relationship between the deformation of the cylinder of the hydrogenation reactor 3 with different wall thicknesses, the temperature difference between the inner and outer walls and the heat input during the cladding process.

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

[0046] When the wall thickness of the cylinder of the hydrogenation reactor 3 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 the present invention, the heat input of the base layer, the transition layer and the corrosion-resistant layer are determined by simulating and analyzing the relationship between the deformation of the barrel of the hydrogenation reactor 3 with different wall thicknesses, the temperature difference between the inner and outer walls and the heat input during the cladding process, so that the heat input ranges of different layers are effectively controllable.

[0048] According to the present invention, the dehydrogenation and tempering heat treatment sequentially comprises dehydrogenation, tempering, furnace cooling and air cooling;

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

[0050] The heating rate of 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 air cooling temperature is 25-35℃.

[0053] According to the present invention, the number of dehydrogenation and tempering heat treatments is determined before the dehydrogenation and tempering heat treatments;

[0054] The number of dehydrogenation and tempering heat treatments is determined by simulating and analyzing the relationship between the residual stress field of the welding end faces of the support platform 2 with different widths and the number of heat treatments during the dehydrogenation and tempering heat treatment.

[0055] Preferably, when the width of the welding end surface of the support platform 2 is not greater than 60 mm, a dehydrogenation and tempering heat treatment is performed after the surfacing base is completed;

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

[0057] When the width of the welding end face of the support platform 2 is not less than 100 mm, a dehydrogenation and tempering heat treatment is performed once when the cladding base layer reaches 1 / 3 of the thickness, 2 / 3 of the thickness, and after completion.

[0058] In the present invention, the number of dehydrogenation and tempering heat treatments is determined by simulating and analyzing the relationship between the residual stress field of the welding end faces of the support platform 2 of different widths and the number of heat treatments during the dehydrogenation and tempering heat treatment process, so that the dehydrogenation and tempering heat treatment process is accurately controllable.

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

[0060] In the present invention, by opening a stress groove 1 on the inner wall of the hydrogenation reactor 3, it is ensured that the root of the support platform 2 is 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 welding residual stress is reduced by 45%.

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

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

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

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

[0065] The temperature for preheating again is 100-200℃;

[0066] During the cladding process, the temperature difference between any two layers of the base layer, transition layer and corrosion-resistant layer shall not exceed 250°C.

[0067] The method of the present invention realizes the integrated control of support platform welding stress-deformation-structure, and effectively solves the bottleneck problems of large stress and deformation and coarse grains of the support platform on the hydrogenation reactor 3.

[0068] The present invention is described in more detail below through a specific embodiment.

[0069] Example 1

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

[0071] A stress groove 1 is provided on the inner wall of the hydrogenation reactor 3. The stress groove 1 has a width of 100 mm and a height of 20 mm. The welding end surface of the support platform 2 is placed in the stress groove 1.

[0072] Preheat the hydrogenation reactor 3 to 150°C, use a heat input of 27KJ / cm, and use the strip electrode electroslag cladding technology to clad the base in the stress groove 1. When the base is clad to a thickness of 7.5mm, perform a heat treatment, and when it is clad to 15mm, perform a heat treatment again. The heat treatment process is: dehydrogenation heat treatment at 300°C, keep warm for 2 hours, then heat up to 620°C at 50°C / min for tempering heat treatment, keep warm for 3 hours, furnace cool to 400 degrees, and then air cool to 30°C;

[0073] After the base is heat treated, the base and the barrel are machined to remove the excess and deformation of the base and the barrel;

[0074] Preheat the hydrogenation reactor again to 150°C with a heat input of 22KJ / cm, perform dehydrogenation heat treatment at 300°C after surfacing the transition layer on the base layer, keep the temperature for 2 hours, and then air cool;

[0075] Using 22KJ / cm heat input, the corrosion-resistant layer is directly clad on the transition layer;

[0076] Each layer of surfacing welding is operated continuously and completed in one go without interruption; at the same time, the temperature difference between each layer is not greater than 250℃.

[0077] From the above comparison, it can be seen that the present embodiment provides a hydrogenation reactor support platform welding method that effectively regulates the welding residual stress and deformation of the support platform 2, and the organizational morphology is also improved, the grains are refined, and the grain size is controlled at about level 8, thereby realizing the integrated regulation of the welding stress-deformation-organization of the support platform 2, and effectively solving the problems of large surfacing stress and deformation and coarse grains of the support platform 2 on the hydrogenation reactor 3.

[0078] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for welding a hydrogenation reactor support, characterized in that: The method comprises the following steps: A stress groove is provided on the inner wall of the hydrogenation reactor, wherein the stress groove is adapted to the welding end surface of the support platform, and the welding end surface of the support platform is placed in the stress groove; Preheating the hydrogenation reactor, surfacing a base layer in the stress groove gap around the welding end face and performing dehydrogenation and tempering heat treatment; preheating the hydrogenation reactor again, and performing a dehydrogenation heat treatment after surfacing a transition layer on the base layer; A corrosion-resistant layer is built-up on the transition layer.

2. The method according to claim 1, characterized in that The dimensions of the stress groove and the support platform satisfy the following relationship: σ1=σ2+2(8~10)mm; Among them, 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.

3. The method according to claim 1, characterized in that Before surfacing the base layer, before surfacing the transition layer, and before surfacing 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 base layer heat input, transition layer heat input and corrosion resistant layer heat input are all determined 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 cladding process.

4. The method according to claim 3, characterized in that When the wall thickness of the hydrogenation reactor cylinder is 100-300 mm, the heat input of the base layer is 20-25 KJ / cm, the heat input of the transition layer is 15-20 KJ / cm, and the heat input of the corrosion-resistant layer is 15-20 KJ / cm; When the wall thickness of the hydrogenation reactor cylinder 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.

5. The method according to claim 1, characterized in that The dehydrogenation and tempering heat treatment includes dehydrogenation, tempering, furnace cooling and air cooling in sequence; The temperature of the hydrogen removal is 250-350°C and the time is 1-3 hours; The tempering temperature rise rate is 40-60°C / min, the final temperature is 550-650°C, and the time is 2-6 hours; The furnace cooling temperature is 350-450°C; The air cooling temperature is 25-35°C.

6. The method according to claim 5, characterized in that Determining the number of dehydrogenation and tempering heat treatments before the dehydrogenation and tempering heat treatment; The number of dehydrogenation and tempering heat treatments is determined by simulating and analyzing the relationship between the residual stress field of the welding end faces of support platforms of different widths and the number of heat treatments during the dehydrogenation and tempering heat treatment.

7. The method according to claim 6, characterized in that When the width of the welding end surface of the support platform is not greater than 60 mm, a dehydrogenation and tempering heat treatment is performed after the surfacing base is completed; When the width of the support platform welding end face is 60mm-90mm, a dehydrogenation and tempering heat treatment is performed when the cladding base layer reaches 1 / 2 thickness and after completion; When the width of the support platform welding end face is not less than 100 mm, dehydrogenation and tempering heat treatment is performed once when the cladding base layer reaches 1 / 3 of the thickness, 2 / 3 of the thickness, and after completion.

8. The method according to claim 1, characterized in that: After the dehydrogenation and tempering heat treatment, the base layer and the cylinder of the hydrogenation reactor are polished and the excess and deformation are removed.

9. The method according to claim 1, characterized in that: The dehydrogenation heat treatment includes dehydrogenation and air cooling in sequence; The temperature of the hydrogen removal is 250-350°C and the time is 1-3 hours; The air cooling temperature is 25-35°C.

10. The method according to claim 1, characterized in that The preheating temperature is 100-200°C; The re-preheating temperature is 100-200°C; During the surfacing process, the temperature difference between any two layers of the base layer, transition layer and corrosion-resistant layer is not greater than 250°C.

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