Method for in-flight assembly and heat treatment of chemical towers

Abstract

The application discloses a method for chemical tower and vessel aerial assembly and heat treatment, relates to the field of chemical tower and vessel aerial assembly, and solves the problem that the influence of wind load is not considered when heat treatment is performed on the existing vertical assembly of the chemical tower and vessel, and the chemical tower and vessel is easily deformed when the strength of the chemical tower and vessel is insufficient, and the problem of instability and collapse is caused in a serious case, and the following scheme is provided, which calculates the actual compressive stress of the girth weld by the influence of the wind load on the tower and vessel, combines the actual compressive stress of the girth weld with the allowable stress, obtains a safety coefficient, analyzes and judges whether reinforcement is needed before the heat treatment of the tower and vessel, and the assembly fixture is arranged to facilitate operation. The method can obtain the accurate value of the compressive stress of the girth weld before the aerial assembly heat treatment of the chemical tower and vessel, helps to determine whether reinforcement is needed during the heat treatment, and guarantees the stability of the tower and vessel structure.

Description

Technical Field

[0001] This invention relates to the field of aerial assembly of chemical towers, and more particularly to a method for aerial assembly and heat treatment of chemical towers. Background Technology

[0002] Due to limitations in transportation conditions and hoisting capacity, large chemical towers are generally manufactured in sections at the factory or prefabrication site. After being transported to the site, they are hoisted, assembled, and welded in sections. Depending on the different materials of the tower, the circumferential welds assembled and welded in the air on site are subjected to heat treatment to relieve welding stress.

[0003] There are two ways to assemble and weld towers on site. One is horizontal assembly and welding. After the assembly and welding are completed and the inspection is passed, the whole unit is hoisted. This method is extremely convenient for both assembly and welding and heat treatment, and it also greatly reduces high-altitude operations. However, it also brings great difficulties to hoisting, requiring larger hoisting equipment for hoisting. This method carries greater risks and higher economic investment.

[0004] Another assembly method is vertical assembly. First, the first section of the tower is erected on the foundation. After alignment, the anchor bolts are tightened. Then, the second section is hoisted and assembled in the air. The circumferential weld between the first and second sections is then welded. Finally, the third section is hoisted, and local stress-relieving heat treatment is performed on the circumferential welds. This method can use smaller hoisting equipment, making it far more economical than the previous method. Therefore, it is generally used when the site schedule allows.

[0005] The method of aerial assembly is now mature, but problems are prone to occur during aerial heat treatment of the circumferential weld. Generally, Q245R steel is heat-treated at 580℃-620℃, and 09MnNiRD steel at 520℃-600℃. At this temperature, the material strength is significantly reduced. Although the tower design does not consider the strength reduction caused by aerial heat treatment, it comprehensively considers other loads, such as the internal (external) pressure during tower operation and external loads like wind, snow, and seismic loads. During on-site heat treatment, only wind load exists, thus the tower has a large strength reserve, and the probability of problems during tower heat treatment is low. Previously, the strength of the tower was generally not considered during heat treatment. The resulting hidden danger is that insufficient tower strength may lead to tower deformation, and in severe cases, instability and collapse. Therefore, a method for aerial assembly and heat treatment of chemical towers is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a method for aerial assembly and heat treatment of chemical towers, which solves the problem that the existing vertical assembly of chemical towers does not adequately consider the impact of wind load during heat treatment. When the strength of the chemical tower is insufficient, it is easy to cause deformation of the chemical tower, and in severe cases, instability and collapse may occur.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for aerial assembly and heat treatment of a chemical tower, comprising the following steps:

[0008] S1: Perform beveling on at least two tower sections to be assembled, make assembly clamps, position the tower sections in the air, install the assembly clamps, adjust the alignment of the tower sections using the assembly clamps, and then assemble and fix the tower sections.

[0009] S2: Arc welding is used to weld the gap between the assembled and fixed tower sections. Specifically, multiple welding sections are welded simultaneously. Before welding multiple sections, spot welding is performed in the bevel. After welding is completed, a circumferential weld is formed.

[0010] S3: Conduct a stability check on the circumferential weld at the connection between the two completed tower sections. If the check is qualified, perform heat treatment on the two completed tower sections. If the check is not qualified, reinforce them and then perform heat treatment. Specifically, the stability check involves combining the actual compressive stress borne by the circumferential weld with the allowable stress to obtain a safety factor for analysis and judgment.

[0011] Preferably, during the beveling process described in S1, the beveling is formed into a V-shaped single-sided beveling or a U-shaped single-sided beveling.

[0012] Preferably, the stability check specifically includes:

[0013] Obtain the compressive stress σ1 of the upper end of the circumferential weld on the circumferential weld and the compressive stress σ2 of the wind load on the circumferential weld;

[0014] σ 压 =σ 1+ σ2

[0015] Safety factor K = B / σ 压

[0016] Where B is the allowable stress of the tower section.

[0017] Preferably, in step S3, the tower section is lifted and stabilized using a crane hook, ensuring that the center of the hook coincides with the center of the tower section. The load of the crane is 0.95-1.05 times the weight of the upper tower section.

[0018] Preferably, the assembly clamp in S1 includes a hanger, and two layers of collars are connected inside the hanger to engage the upper and lower tower sections. Multiple sliding frames are arrayed inside the collars. Sliding seats are slidably connected to both sides of each sliding frame. A rotating plate is rotatably connected to each sliding seat, and a clamping plate is rotatably connected to the rotating plate. A T-shaped block is slidably connected inside the sliding seat. A two-way telescopic rod is connected to the collar, and a push plate is connected through the two-way telescopic rod. The push plate slides in contact with the T-shaped block to push the T-shaped block to slide radially outward along the collar. A driving mechanism is provided on the collar to drive the T-shaped blocks that slide to the outside of the sliding frame to move away from each other.

[0019] Preferably, the inner side of the collar is fixedly connected with multiple connecting seats and connected to the slide frame through the connecting seats. The inner walls on both sides of the slide frame are provided with slide grooves, and sliders are connected to both sides of the slide seat. The sliders are slidably connected in the slide grooves.

[0020] Preferably, a slide rail is connected to the slide block, a guide block is connected to the T-shaped block, the guide block is slidably connected inside the slide rail, a guide rod is connected to the inner wall of the slide rail, the guide block is slidably sleeved on the outer side of the guide rod, a spring is sleeved on the outer side of the guide rod, the two ends of the spring are respectively connected to the slide rail and the guide block, an inclined block is connected to the T-shaped block, and the push plate slides in contact with the T-shaped block through the inclined block.

[0021] Preferably, the inner side of the collar is connected to a mounting base, the second bidirectional telescopic rod is embedded in the mounting base, and the two ends of the second bidirectional telescopic rod are located on the upper and lower sides of the collar and connected to a ring. Each push plate is in a group of three, and the push plates in the group are connected to the ring in an array with gradually decreasing lengths.

[0022] Preferably, the driving mechanism includes a bidirectional telescopic rod and a top ring. The bidirectional telescopic rod is arrayed and embedded in the collar and extends to the upper and lower sides of the collar respectively. Each extension end is connected to a top ring, and the upper and lower top rings respectively cooperate with and abut against the upper and lower T-shaped blocks.

[0023] Preferably, both ends of the rotating plate are rotatably connected to the slide and the clamping plate via spiral hinges. A second spring is also provided in the slide groove, and both ends of the second spring are connected to the slide groove and the slider. Bolt holes are also provided on the clamping plate, and bolts are provided in the bolt holes. A heating device is installed on the clamping plate via bolts.

[0024] Compared with related technologies, the method for aerial assembly and heat treatment of chemical towers provided by the present invention has the following beneficial effects:

[0025] This invention calculates the actual compressive stress borne by the circumferential weld based on the influence of wind load on the tower, and combines the actual compressive stress borne by the circumferential weld with the allowable stress to obtain a safety factor. This is used to analyze and judge whether the tower needs to be reinforced before welding heat treatment, ensuring that the structural strength of the tower itself is sufficient during welding heat treatment, and avoiding instability and collapse.

[0026] This invention also includes a self-made assembly clamp. By driving the T-shaped block inside the slide block to slide, the rotating plate is rotated to control the clamping plate. This allows the clamping plate inside the upper collar to be clamped onto the upper tower section first, and then the clamping plate inside the lower collar to be clamped onto the lower tower section. This allows the upper and lower tower sections to be gradually aligned, improving docking efficiency. At the same time, the number of clamping plates can be adjusted to facilitate clamping tower sections of different sizes and models, thus improving versatility. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the dimensions and structure of the welded tower, as specified in invention number C2202.

[0028] Figure 2 This is a schematic diagram of the dimensions and structure of the welded tower, which is numbered C2204 in this invention.

[0029] Figure 3 This is a schematic diagram of the dimensions and structure of the welded tower, as specified in invention number C2205.

[0030] Figure 4 This is a schematic diagram of the assembly clamp of the present invention.

[0031] Figure 5 This is a schematic diagram of the single-layer collar and related structures on the collar of the present invention.

[0032] Figure 6 This is a schematic diagram of the sliding frame and its internal structure according to the present invention.

[0033] Figure 7 This is a schematic diagram of the array structure of the various push plates and slides of the present invention.

[0034] Figure 8 This is a cross-sectional view of the single-layer collar structure of the present invention.

[0035] In the diagram: 1. Hanger; 2. Collar; 3. Connecting seat; 4. Slide frame; 5. Bidirectional telescopic rod one; 6. Top ring; 7. Slide seat; 8. Rotating plate; 9. Clamping plate; 10. Bolt hole; 11. Slide groove; 12. Slider; 13. Slide rail; 14. Guide block; 15. Guide slide rod; 16. Spring one; 17. T-block; 18. Inclined block; 19. Mounting seat; 20. Bidirectional telescopic rod two; 21. Ring; 22. Push plate. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] This invention provides a technical solution: a method for aerial assembly and heat treatment of chemical towers, comprising the following steps:

[0038] S1: Perform beveling on at least two tower sections to be assembled, make assembly clamps, position the tower sections in the air, install the assembly clamps, adjust the alignment of the tower sections using the assembly clamps, and then assemble and fix the tower sections.

[0039] During beveling, the bevel is formed into a V-shaped single-sided bevel or a U-shaped single-sided bevel;

[0040] S2: Arc welding is used to weld the gap between the assembled and fixed tower sections. Specifically, multiple welding sections are welded simultaneously. Before welding multiple sections, spot welding is performed in the bevel. After welding is completed, a circumferential weld is formed.

[0041] S3: Conduct a stability check on the circumferential weld at the connection between the two completed tower sections. If the check is qualified, perform heat treatment on the two completed tower sections. If the check is not qualified, reinforce them and then perform heat treatment. Specifically, the stability check involves combining the actual compressive stress borne by the circumferential weld with the allowable stress to obtain a safety factor for analysis and judgment.

[0042] The stability check specifically includes:

[0043] Obtain the compressive stress σ1 of the upper end of the circumferential weld on the circumferential weld and the compressive stress σ2 of the wind load on the circumferential weld;

[0044] σ 压 =σ 1+ σ2

[0045] Safety factor K = B / σ 压

[0046] Where B is the allowable stress of the tower section, and the specific calculation process of the safety factor is based on the standards such as "Steel Pressure Vessels" GB150-2011 and "Tower Vessels" NB / T 47041. The relevant calculation process in this method refers to the above or existing standards.

[0047] In step S3, the tower section is lifted and stabilized using the crane hook, ensuring that the center of the hook coincides with the center of the tower section. The load of the crane is 0.95-1.05 times the weight of the upper tower section.

[0048] Please see Figure 4-7 The present invention provides a technical solution: the assembly clamp in S1 includes a hanger 1, and two layers of collars 2 are connected inside the hanger 1 to clamp the upper and lower tower sections. Multiple sliding frames 4 are arrayed inside the collars 2, such as... Figure 4 As shown, the hanger 1 is fitted on the outside of the collar 2, and the collar 2 is arranged in two symmetrical layers inside the hanger 1.

[0049] Slide seats 7 are slidably connected to both sides of the inner side of the slide frame 4. Each slide seat 7 is rotatably connected to a rotating plate 8, and a clamping plate 9 is rotatably connected to the rotating plate 8. A T-shaped block 17 is slidably connected inside the slide seat 7. Figure 5 As shown, the upper and lower slide blocks 7 can slide closer or further apart, thereby causing the clamping plates 9 arranged in various circumferential arrays to move synchronously, either dispersed or gathered together.

[0050] A bidirectional telescopic rod 20 is connected to the collar 2, and a push plate 22 is connected through the bidirectional telescopic rod 20. The push plate 22 slides against the T-shaped block 17 to push the T-shaped block 17 to slide radially outward along the collar 2. A drive mechanism is provided on the collar 2 to drive the T-shaped blocks 17 that slide to the outside of the slide frame 4 to move away from each other. Figure 5 , 6 As shown in Figure 7, the retraction of the bidirectional telescopic rod 20 first causes the upper and lower push plates 22 to move closer together, and the sliders 17 that slide in the slide block 7 on their respective sides slide together, pushing the sliders 17 that were originally located on the inner side of the slide frame 6 along the collar 2 to the outer side. Then, the drive mechanism can drive the upper and lower slide blocks 7 to move away from each other, so as to drive the clamping plates 9 to move closer together and clamp the tower section inside.

[0051] Multiple connecting seats 3 are fixedly connected to the inner side of the collar 2, and are connected to the slide frame 4 through the connecting seats 3. Slide grooves 11 are provided on both inner walls of the slide frame 4. Slide blocks 12 are connected to both sides of the slide seat 7, and the slide blocks 12 are slidably connected within the slide grooves 11, as shown in the attached diagram. Figure 2 As shown, the connecting seat 3 allows the sliding frame 4 to be connected to it and located inside the collar 2, which facilitates the installation of a drive mechanism on the collar 2. At the same time, the sliding groove 11 and the slider 12 can stabilize the sliding of the upper and lower sliding seats 7 inside the sliding frame 4.

[0052] A slide rail 13 is connected to the slide block 7, and a guide block 14 is connected to the slider 17. The guide block 14 is slidably connected inside the slide rail 13. A guide rod 15 is connected to the inner wall of the slide rail 13. The guide block 14 is slidably sleeved on the outside of the guide rod 15. A spring 16 is sleeved on the outside of the guide rod 15. The two ends of the spring 16 are connected to the slide rail 13 and the guide block 14, respectively. Figure 6 As shown, the guide rod 15 makes the sliding of the guide block 14 within the slide rail 13 more stable. The spring 16 ensures that without external force, the spring 16 will push the guide block 14, thereby causing the slider 17 to slide radially inward toward the collar 2 and onto the inner side of the slide frame 4. The slider 17 is connected to an inclined block 18, and the push plate 22 slides in contact with the slider 17 through the inclined block 18. This allows the push plate 22 to push the slider 17 indirectly to slide outward toward the slide frame 4 through its cooperation with the inclined block 18, improving the smoothness of the sliding between them.

[0053] The inner side of the collar 2 is connected to a mounting base 19. A bidirectional telescopic rod 20 is embedded in the mounting base 19, with both ends of the bidirectional telescopic rod 20 positioned on the upper and lower sides of the collar 2 and connected to a circular ring 21. Each push plate 22 is arranged in groups of three, with the length of the push plates 22 within each group gradually decreasing as they are arrayed on the circular ring 21. Figure 5 , 7 As shown, the mounting base 19 facilitates the installation of the bidirectional telescopic rod 20 inside the collar 2, and allows the bidirectional telescopic rod 20 to be positioned inside the sliding frame 4. The ring 21 allows each set of push plates 22 to move downwards synchronously. Furthermore, since each set of push plates 22 consists of three plates with progressively shorter lengths, Figure 7 As can be seen, there are actually 12 push plates 22, which are four groups. When the bidirectional telescopic rod 20 retracts and drives the two side rings 21 to move closer to each other, the longest push plate 22 in each group will first be driven to fit against the inclined block 18, thus pushing the slider 17 to slide. At this time, one push plate 22 in each group will first fit against the inclined block 18 and slide, that is, first push the slider 17 on the slide seat 7 in the four slide frames 4 to slide. As the bidirectional telescopic rod 20 continues to retract, it will again drive the second longest push plate 22 in each group to fit against the inclined block 18 and slide, and so on. This allows the number of sliders 17 sliding out of the slide frame 4 to be adjusted by the degree of retraction of the bidirectional telescopic rod 20. It also facilitates the simultaneous convergence of 4, 8 or 12 clamping plates during the operation of the drive mechanism to adjust and clamp tower sections of different sizes and specifications.

[0054] Furthermore, the number of push plates 22 is the same as the number of slide frames 4, and they are set synchronously. The length changes in each set of push plates 22 are carried out in the same direction along the circumference of the collar 2.

[0055] The drive mechanism includes a bidirectional telescopic rod 5 and a top ring 6. The bidirectional telescopic rod 5 is arrayed and embedded in the collar 2, extending to the upper and lower sides of the collar 2 respectively, and a top ring 6 is connected to each extension end. The upper and lower top rings 6 respectively cooperate and abut against the upper and lower sliders 17. Figure 5 As described above, when the bidirectional telescopic rod 20 retracts to an appropriate length and drives the required number of sliders 17 to slide along the collar 2 to the outside of the slide frame 4, the drive mechanism can be activated, that is, the bidirectional telescopic rod 5 is controlled to extend, which can push the top rings 6 on the upper and lower sides to move away from each other, and push the sliders 17 on the outer radial end of the slide frame 4 along the collar 2, so as to drive the upper and lower slide seats 7 to move away from each other, and then drive the clamping plates 9 to converge through the rotating plate 8, so as to clamp the middle tower section.

[0056] Both ends of the rotating plate 8 are rotatably connected to the slide block 7 and the clamping plate 9 via spiral hinges. A second spring is also provided in the slide groove 11, and both ends of the second spring are connected to the slide groove 11 and the slider 12. The clamping plate 9 is also provided with bolt holes 10, and bolts are provided in the bolt holes 10. The clamping plate 9 is equipped with heating equipment by bolts. Spiral hinges are provided at both ends of the rotating plate 8. Through the force of the spiral hinges at both ends of the rotating plate 8, the upper and lower slide blocks 7 tend to move closer to each other in the slide frame 4. This allows the upper and lower slide blocks 7 to be in a state of close proximity when the drive mechanism is not running, thereby driving the clamping plates 9 to move away from each other and disperse, so as to facilitate clamping operation on the outside of the tower section. The setting of the second spring can also further assist the upper and lower slide blocks 7 to move closer to each other. Heating equipment can also be installed on the clamping plate 9 by bolts, so that the high-altitude circumferential weld heat treatment can be carried out directly through the heating equipment installed on the clamping plate 9.

[0057] The stability check in S3 specifically involves combining the actual compressive stress borne by the circumferential weld with the allowable stress to derive a safety factor for analysis and judgment. The calculation process is shown below.

[0058] When checking the stability of circumferential welds based on wind load influencing factors, the specific method is as follows:

[0059] (1): The compressive stress of the upper section weight on the circumferential weld is:

[0060] σ1=155000×9.8 / (3.14×4×0.055)=2.199Mpa;

[0061] (2): The influence of wind load:

[0062] Wind load has the greatest impact on the heat treatment process and is the focus of the calculation. The horizontal pressure of the first section of the cylinder is:

[0063] P i =K1·K1i·q 。 ·fi ·L i ·d0i

[0064] In the formula:

[0065] <![CDATA[q 。 The basic wind pressure value at this location is 410 N / m. 2 —Based on the design drawings]]> <![CDATA[f i : Wind pressure height change value]]> <![CDATA[L i Section 1: Calculating Height <![CDATA[K1i: wind vibration coefficient of the calculation section, which is 1.7 when the height H ≤ 20m]]>

[0066] When H > 20m, the calculation is as follows:

[0067] (K1i=1+ξ·V i ·φ2i / f i )

[0068] Where: ξ is the pulsation amplification coefficient;

[0069] Vi pulse influence coefficient;

[0070] φzi vibration coefficient;

[0071] (3) with Figure 1 Taking tower C2202 as an example, the wind vibration coefficient of the K1i calculation section is calculated:

[0072] 1) Calculate q1·T1 2 value:

[0073] q1 Class B area q1=410(N / m 2 );

[0074] T1 has a natural oscillation period of S0;

[0075]

[0076] m0—Total mass of the calculated section (Kg) m0=155000Kg;

[0077] H—Height of the straight section (mm) H=66540mm;

[0078] δe—wall thickness (mm) δe=55mm;

[0079] Di—Inner diameter (mm) Di=4000mm;

[0080] E—Material elastic modulus E=122.45GPa;

[0081]

[0082] q1·T1 2 =410 * 0.92982 = 354.46;

[0083] From the table, we find ξ = 2.1945;

[0084] 2) Calculation of Vi:

[0085] Section 1: Based on Hit = 50.412, for Category B regions, refer to Table 14-6, Vi1 = 0.8656;

[0086] Section 2: Based on Hit = 61.626M, for Category B areas, refer to Table 14-6, Vi2 = 0.8808;

[0087] 3) Calculation of φzi:

[0088] Section 1: Based on Hit / H = 50.412 / 66.54 = 0.7576, u = 1, refer to Table 14-7, φzi = 0.6749;

[0089] Section 2: Based on Hit / H = 61.626 / 66.54 = 0.9261, u = 1, refer to Table 14-7, φzi = 0.9039;

[0090] 4) Calculation of K1i:

[0091] Section 1: K1i = 1 + 2.1945 * 0.8656 * 0.6749 / 1.73 = 1.741;

[0092] Section 2: K2i = 1 + 2.1945 * 0.8808 * 0.9039 / 1.83 = 1.955.

[0093] 1. Please refer to Figure 1 Provide the welded tower unit, numbered C2202, with a controlled weight G of 155T. Conduct a feasibility analysis on the butt weld of the upper section of the tower unit's cylindrical section. Given the upper section's shape characteristics, divide it into two sections. Calculate the wind pressure and its bending moment.

[0094] (1) First section of the cylinder: (44.912m-55.912m)

[0095] L1 = 11m, d 0i = 4.11m, H1 = 5.5m, and the height of its top cross-section from the ground is 55.912m. According to relevant data, the f of this section of the cylinder... i =1.73;

[0096] Wind pressure: P i =0.7×1.741×410×1.73×11×4.11=39080.6N;

[0097] The bending moment of the wind on the circumferential weld: M1=P1·H1=39080.6×5.5=214943.3(N·M); (2) Second section of the cylinder: (55.912-66.54m)

[0098] L2 = 11.428m, d 0i= 4.11m, H2 = 16.714m, and the height of its top cross-section from the ground is 66.54m. From relevant data, the f of the cylinder is... i =1.83;

[0099] Wind pressure P2 = 0.7 × 1.955 × 410 × 1.83 × 11.428 × 4.11 = 48227.2 N;

[0100] The bending moment of the wind on the circumferential weld: M2=P2·H2=48227.2×16.714=806069.4(N·M);

[0101] (3) Total bending moment of the circumferential weld: M 风 =M1+M2=1021012.7(N·M);

[0102] (4) Bending moment caused by eccentricity (the center offset is allowed by 30mm according to the installation specifications):

[0103] M 偏 =155000×9.8×0.03=45570(N·M);

[0104] (5) The section modulus W of the circumferential weld cross-section is:

[0105] I = 3.14 × (D) 4 -d 4 ) / 64=1.43m 4 ;

[0106] W = I / e = 1.43 / 2.055 = 0.7m 3 ;

[0107] (6) Assuming the wind bending moment and the eccentric bending moment are concentric, the maximum pressure generated by the bending moment is: σ2=(M 风 +M 偏 W / W = 1.524 MPa;

[0108] Therefore, the actual compressive stress borne by the circumferential weld is:

[0109] σ 压 =σ1+σ2=2.199+1.524=3.723Mpa.

[0110] 2. Please refer to Figure 2 Provide the welded tower unit, numbered C2204, with a controlled weight G of 65T. Conduct a feasibility analysis on the butt weld of the upper section of the tower unit's cylindrical section. The upper section's shape is divided into three sections. Calculate the wind pressure and its bending moment.

[0111] (1) First section of the cylinder: (45.823m-57.223m)

[0112] L1 = 11.4m, d 0i =3.932m, H1=5.7m, and the height of its top cross-section from the ground is 57.223m. From relevant data, the f of this section of the cylinder is... i =1.74;

[0113] Wind pressure: P i =0.7×1.71×410×1.74×11.4×3.932=38277.6N;

[0114] The bending moment of the wind on the circumferential weld: M1=P1·H1=38277.6×5.7=218182.3(N·M);

[0115] (2) Second section of the cylinder: (57.223m-66.223m)

[0116] L2=9m、d 0i =2.624m, H2=15.9m, and the height of its top cross-section from the ground is 66.223m. From relevant data, the f of the cylinder is... i =1.82;

[0117] Wind pressure: P2 = 0.7 × 1.9 × 410 × 1.82 × 9 × 2.624 = 23437.6 N;

[0118] The bending moment of the wind on the circumferential weld: M2=P2·H2=23437.6×15.9=372658(N·M);

[0119] (3) Third section of the cylinder: (75.48m-66.223m)

[0120] L3 = 9.257m, d 0i =2.624m, H3 = 25.03m, and the height of its top cross-section from the ground is 75.48m. From relevant data, the f of the cylinder is... i =1.91;

[0121] Wind pressure: P3 = 0.7 × 2.05 × 410 × 1.91 × 9.257 × 2.624 = 27296.2 N;

[0122] The bending moment of the wind on the circumferential weld: M3 = P3·H3 = 27296.2 × 25.03 = 683223.9 (N·M);

[0123] (4) Total bending moment of the circumferential weld: M 风 =M1+M2+M3=1274064.2(N·M);

[0124] (5) Bending moment caused by eccentricity (the center offset is allowed by 30mm according to the installation specifications):

[0125] M 偏 =65000×9.8×0.03=19110(N·M);

[0126] (6) The section modulus W of the circumferential weld cross section is:

[0127] I = 3.14 × (D) 4 -d 4 ) / 64=0.1125m 4 ;

[0128] W=I / e=0.1125 / 1.316=0.0855m 3 ;

[0129] (7) Assuming the wind bending moment and the eccentric bending moment are concentric, the maximum pressure generated by the bending moment is: σ2=(M 风 +M 偏 W / W = 15.12 MPa;

[0130] Therefore, the actual compressive stress borne by the circumferential weld is:

[0131] σ 压 =σ1+σ2=3.25+15.12=18.37Mpa.

[0132] 3. Please refer to Figure 3 Provide the welded tower unit, numbered C2205, with a controlled weight G of 65T. Conduct a feasibility analysis on the butt weld of the upper section of the tower unit's cylindrical section. Given the upper section's shape characteristics, divide it into two sections. Calculate the wind pressure and its bending moment.

[0133] (1) First section of the cylinder: (35.85m-45.85m)

[0134] L1 = 10m, d 0i =3.73m, H1=5m, and the height of its top cross-section from the ground is 45.85m. From relevant data, the f of this section of the cylinder is... i =1.62;

[0135] Wind pressure: P i =0.7×1.797×410×1.62×10×3.73=31164N;

[0136] The bending moment of the wind on the circumferential weld: M1=P1·H1=31164×5=155820(N·M);

[0137] (2) Second section of the cylinder (45.85-54.71m)

[0138] L2 = 8.86m, d 0i=3.73m, H2 = 9.43m, and the height of its top cross-section from the ground is 54.71m. Therefore, the f of the cylinder... i =1.72;

[0139] Wind pressure: P2 = 0.7 × 2.028 × 410 × 1.72 × 8.86 × 3.73 = 33084 N;

[0140] The bending moment of the wind on the circumferential weld: M2=P2·H2=33084×9.43=311982(N·M);

[0141] (3) Total bending moment of the circumferential weld: M 风 =M1+M2=467802(N·M);

[0142] (4) Bending moment caused by eccentricity (the center offset is allowed by 30mm according to the installation specifications):

[0143] M 偏 =65000×9.8×0.03=19110(N·M);

[0144] (5) The section modulus W of the circumferential weld cross-section is:

[0145] I = 3.14 × (D) 4 -d 4 ) / 64=0.3223m 4 ;

[0146] W=I / e=0.3223 / 1.866=0.1727m 3 ;

[0147] (6) Assuming the wind bending moment and the eccentric bending moment are concentric, the maximum pressure generated by the bending moment is: σ2=(M 风 +M 偏 W / W = 2.82 MPa;

[0148] Therefore, the actual compressive stress borne by the circumferential weld is:

[0149] σ 压 =σ1+σ2=3.43+2.82=6.25Mpa.

[0150] 4. The allowable stress is selected from the smaller values ​​calculated by the following formulas:

[0151]

[0152] Where: A = 0.094δ e / R e In the formula δ e —Effective thickness of the cylinder, R e--Outer radius of the cylinder, E t —The elastic transverse at temperature t.

[0153] The high-temperature test of Q245R at 620℃, its E t =107.9 GPa, yield strength σ 0.2 =68.85MPa;

[0154] The high-temperature test of 09MnNiRD at 580℃ showed that its E t =122.45 GPa, yield strength σ 0.2 =133.8MPa;

[0155] Q245R takes the minimum value: B = 25.9;

[0156] The minimum value of 09MnNiRD is: B = 97.96;

[0157] The upper circumferential weld of C2202 has a pressure of 3.803 mPa, so the safety factor K = B / σ 压 =97.96 / 3.723=26.31;

[0158] The upper circumferential weld of C2204 has a pressure of 19.28 mPa, so the safety factor K = B / σ 压 =97.96 / 18.37=5.33;

[0159] The upper circumferential weld of C2205 has a pressure of 6.25 MPa, so the safety factor K = B / σ 压 =25.9 / 6.25=4.144;

[0160] C2201 was not calculated because its wall thickness and material are similar to and superior to C2202 and C2205.

[0161] Conclusion: Due to its thicker wall, C2202 has a larger moment of inertia I and bending section modulus W, so no reinforcement measures are required; C2205 and C2204 require crane stabilization measures and heat treatment to ensure safety and stability.

[0162] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for aerial assembly and heat treatment of a chemical tower, characterized in that, Includes the following steps: S1: Perform beveling on at least two tower sections to be assembled, make assembly clamps, position the tower sections in the air, install the assembly clamps, adjust the alignment of the tower sections using the assembly clamps, and then assemble and fix the tower sections. The assembly fixture described in S1 includes a hanger (1), and the hanger (1) is connected to two layers of collars (2) that engage the upper and lower tower sections. Multiple sliding frames (4) are arrayed on the inner side of the collars (2). Sliding seats (7) are slidably connected on both sides of the sliding frames (4). A rotating plate (8) is rotatably connected to each sliding seat (7), and a clamping plate (9) is rotatably connected to the rotating plate (8). A T-shaped block (17) is slidably connected inside the sliding seat (7). A two-way telescopic rod (20) is connected to the collar (2), and a push plate (22) is connected through the two-way telescopic rod (20). The push plate (22) slides against the T-shaped block (17) to push the T-shaped block (17) to slide radially outward along the collar (2). A driving mechanism is provided on the collar (2) to drive the T-shaped blocks (17) that slide to the outside of the sliding frame (4) to move away from each other. S2: Arc welding is used to weld the gap between the assembled and fixed tower sections. Specifically, multiple welding sections are welded simultaneously. Before welding multiple sections, spot welding is performed in the bevel. After welding is completed, a circumferential weld is formed. S3: Conduct a stability check on the circumferential weld at the connection between the two completed tower sections. If the check is qualified, perform heat treatment on the two completed tower sections. If the check is not qualified, reinforce them and then perform heat treatment. Specifically, the stability check involves combining the actual compressive stress borne by the circumferential weld with the allowable stress to obtain a safety factor for analysis and judgment. The stability check specifically includes: Obtain the compressive stress σ1 of the upper end of the circumferential weld on the circumferential weld and the compressive stress σ2 of the wind load on the circumferential weld; ； Safety factor K = B / σ 压 Where B is the allowable stress of the tower section.

2. The method for aerial assembly and heat treatment of a chemical tower according to claim 1, characterized in that, During the beveling process described in S1, the beveling is formed into a V-shaped single-sided beveling or a U-shaped single-sided beveling.

3. The method for aerial assembly and heat treatment of a chemical tower according to claim 1, characterized in that, In step S3, the tower section is lifted and stabilized using the hook of a crane, ensuring that the center of the hook coincides with the center of the tower section. The load of the crane is 0.95-1.05 times the weight of the upper tower section.

4. The method for aerial assembly and heat treatment of a chemical tower according to claim 1, characterized in that, The inner side of the collar (2) is fixedly connected with multiple connecting seats (3), and is connected to the slide frame (4) through the connecting seats (3). The inner walls on both sides of the slide frame (4) are provided with slide grooves (11). The slide seat (7) is connected to sliders (12) on both sides. The sliders (12) are slidably connected in the slide grooves (11).

5. The method for aerial assembly and heat treatment of a chemical tower according to claim 1, characterized in that, The slide block (7) is connected to a slide rail (13), and the T-shaped block (17) is connected to a guide block (14). The guide block (14) is slidably connected inside the slide rail (13). The inner wall of the slide rail (13) is connected to a guide rod (15). The guide block (14) is slidably sleeved on the outside of the guide rod (15). A spring (16) is sleeved on the outside of the guide rod (15). The two ends of the spring (16) are respectively connected to the slide rail (13) and the guide block (14). The T-shaped block (17) is connected to an inclined block (18). The push plate (22) slides against the T-shaped block (17) through the inclined block (18).

6. The method for aerial assembly and heat treatment of a chemical tower according to claim 4, characterized in that, The inner side of the collar (2) is connected to the mounting base (19). The two-way telescopic rod (20) is embedded in the mounting base (19), and the two ends of the two-way telescopic rod (20) are located on the upper and lower sides of the collar (2) and connected to the ring (21). Each of the push plates (22) is in a group of three, and the push plates (22) in the group are connected to the ring (21) in an array with gradually shortening lengths.

7. The method for aerial assembly and heat treatment of a chemical tower according to claim 4, characterized in that, The driving mechanism includes a bidirectional telescopic rod (5) and a top ring (6). The bidirectional telescopic rod (5) is arrayed and embedded in the collar (2) and extends to the upper and lower sides of the collar (2) respectively. The top ring (6) is connected to the extension end of each of the two sides. The top ring (6) on the upper and lower sides respectively cooperates with the T-shaped block (17) on the upper and lower sides to abut.

8. The method for aerial assembly and heat treatment of a chemical tower according to claim 4, characterized in that, Both ends of the rotating plate (8) are rotatably connected to the slide block (7) and the clamping plate (9) through a spiral hinge. A second spring is also provided in the slide groove (11). Both ends of the second spring are connected to the slide groove (11) and the slider (12). A bolt hole (10) is also provided on the clamping plate (9). A bolt is provided in the bolt hole (10). A heating device is installed on the clamping plate (9) through the bolt.

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