Aerial assembly and heat treatment method for chemical tower

Abstract

The invention discloses a chemical tower aerial assembly and heat treatment method, relates to the field of chemical tower aerial assembly, and solves the problems that during heat treatment of existing chemical tower vertical assembly, the influence of wind loads is not considered sufficiently, when the strength of a chemical tower is insufficient, the chemical tower is prone to deformation, and the chemical tower is unstable and collapsed seriously. According to the technical scheme, the actual pressure stress borne by the circumferential weld is calculated according to the influence of the wind load on the tower, the actual pressure stress borne by the circumferential weld is combined with allowable stress, a safety coefficient is obtained, and whether the tower needs to be reinforced or not before welding heat treatment is conducted on the tower is analyzed and judged; therefore, the operation is facilitated. According to the method, the accurate value of the pressure stress borne by the circumferential weld can be obtained before air group heat treatment of the chemical tower, whether reinforcement is needed or not during heat treatment can be determined, and the stability of the tower structure is guaranteed.

Description

Technical Field

[0001] The invention relates to the field of aerial assembly of chemical towers, and in particular to a method for aerial assembly and heat treatment of chemical towers. Background Art

[0002] Due to the limitations of transportation conditions and lifting capacity, large chemical towers are generally manufactured in sections at manufacturing plants or prefabrication sites. After being transported to the site, they are hoisted, assembled and welded in sections. Depending on the different tower materials, the circumferential welds of the on-site aerial assembly need to be heat treated to eliminate welding stress.

[0003] There are two ways to weld the tower on site. One is horizontal welding. After the welding is completed and the inspection is qualified, the tower is hoisted as a whole. This method is extremely convenient for both welding and heat treatment, and it also greatly reduces high-altitude operations. However, it also brings great difficulties to hoisting. Larger hoisting equipment is required for hoisting, which brings greater risks and higher economic investment.

[0004] Another assembly method is vertical assembly, that is, first erect the first section of the tower on the foundation, tighten the anchor bolts after alignment, then hoist the second section for aerial assembly, weld the girth weld between the first and second sections, and finally hoist the third section, and finally perform local stress relief heat treatment on the girth weld. This method can be hoisted with smaller hoisting equipment, and its economy is far greater than the previous method, so this method is generally used when the on-site construction period allows.

[0005] The method of aerial assembly is now mature, but problems are prone to occur in aerial heat treatment of circumferential welds. Generally, Q245R steel is at 580℃-620℃ during heat treatment, and 09MnNiRD steel is at 520℃-600℃. At this time, the strength of the material has been greatly reduced. However, although the tower body was not designed to consider the problem of reduced tower body strength caused by aerial heat treatment, other loads were considered very comprehensively, such as the internal pressure (external pressure) during tower equipment operation and wind loads, snow loads, earthquake loads, etc. from the outside world. Only wind loads exist during on-site heat treatment. Therefore, the tower body has a large strength reserve during heat treatment, and the probability of problems during heat treatment of the tower is not high. In the past, the strength of the tower body was generally not considered during heat treatment. The hidden danger brought about by this is that when the tower body strength is insufficient, the tower body may deform, and in severe cases, instability and collapse may occur. Therefore, a method for aerial assembly and heat treatment of chemical towers is proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a method for aerial assembly and heat treatment of chemical towers, which solves the problem that the influence of wind load is not sufficiently considered during the heat treatment of the existing vertical assembly of chemical towers. When the strength of the chemical tower is insufficient, it is easy to cause deformation of the chemical tower, and in severe cases, it may become unstable and collapse.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for assembling and heat treating a chemical tower in mid-air, comprising the following steps:

[0008] S1: performing groove processing on at least two tower barrel sections to be assembled, making an assembly fixture, positioning the tower barrel section in the air, and installing the assembly fixture, adjusting the mating orientation of the tower barrel section by the assembly fixture, and then assembling and fixing the tower barrel section;

[0009] S2: arc welding is used to weld the gap between the tower cylinder sections after the assembly is fixed. Specifically, multiple sections of welding are carried out simultaneously. Before the multiple sections of welding are carried out, spot welding is first carried out in the groove. After the welding is completed, a circumferential weld is formed.

[0010] S3: Perform a stability check on the girth weld at the connection between the two tower cylinder sections. If the check is qualified, the two tower cylinder sections will be heat treated. If it is unqualified, they will be reinforced and then heat treated. The stability check specifically combines the actual compressive stress on the girth weld with the allowable stress to derive a safety factor for analysis and judgment.

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

[0012] Preferably, the stability check is specifically:

[0013] Obtain the compressive stress σ of the upper end cylinder of the girth weld on the girth weld 1 , wind load compressive stress σ on girth weld 2 ;

[0014] σ 压 =σ 1+ σ 2

[0015] Safety factor K = B / σ 压

[0016] Among them, B is the allowable stress of the tower cylinder section.

[0017] Preferably, in step S3, the tower barrel section is lifted and stabilized by a crane hook, and the center of the hook is ensured to coincide with the center of the tower barrel section, and the load of the crane is 0.95-1.05 times the weight of the upper tower barrel section.

[0018] Preferably, the assembly of clamps in S1 includes a hanger, wherein the hanger is connected with two layers of rings for clamping the upper and lower tower cylinder sections, the inner side array of the rings is connected with a plurality of sliding frames, both sides of the sliding frames are slidably connected with sliding seats, each of the sliding seats is rotatably connected with a rotating plate, and the rotating plate is rotatably connected with a clamping plate, the sliding seat is slidably connected with a T-shaped block, the ring is connected with two bidirectional telescopic rods, and a push plate is connected through the two bidirectional telescopic rods, the push plate and the T-shaped block slide in contact with each other to push the T-shaped block to slide radially outward along the ring, and the ring is provided with a driving mechanism for driving the T-shaped blocks that slide and extend to the outside of the sliding frame to move away from each other.

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

[0020] Preferably, the slide seat is connected to a slide rail, the T-shaped block is connected to a guide block, the guide block is slidably connected in the slide rail, the inner wall of the slide rail is connected to a guide slide rod, the guide block sliding sleeve is arranged on the outer side of the guide slide rod, the outer side of the guide slide rod is sleeved with a spring 1, the two ends of the spring 1 are respectively connected to the slide rail and the guide block, the T-shaped block is connected to an inclined block, and the push plate slides in fit with the T-shaped block through the inclined block.

[0021] Preferably, the inner array of the ring is connected to a mounting seat, the two bidirectional telescopic rods are embedded in the mounting seat, and the two ends of the two bidirectional telescopic rods are located at the upper and lower sides of the ring and are connected to a circular ring, each of the push plates is a group of three, and the array of push plates with gradually shortened lengths in the group is connected to the circular ring.

[0022] Preferably, the driving mechanism includes a bidirectional telescopic rod and a top ring. The bidirectional telescopic rod is embedded in an array in the ring and extends to the upper and lower sides of the ring respectively, and is connected to a top ring at the extended end. The top rings on the upper and lower sides respectively cooperate and interfere with the T-shaped blocks on the upper and lower sides.

[0023] Preferably, both ends of the rotating plate are rotatably connected to the sliding seat and the clamping plate through a scroll hinge, a second spring is also provided in the sliding groove, both ends of the second spring are connected to the sliding groove and the sliding block, a bolt hole is also opened on the clamping plate, a bolt is provided in the bolt hole, and a heating device is installed on the clamping plate through the bolts.

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

[0025] The present invention calculates the actual compressive stress of the girth weld according to the influence of wind load on the tower, and combines the actual compressive stress of the girth weld with the allowable stress to obtain a safety factor to analyze and judge whether reinforcement is required before the tower welding heat treatment, thereby ensuring that the structural strength of the tower itself is sufficient during the welding heat treatment, and avoiding instability and collapse.

[0026] The present invention also has a self-made assembly fixture, which drives the sliding of the T-shaped block in the slide seat to drive the rotating plate to rotate to control the clamping plate, so that the clamping plate in the upper ring is first clamped on the upper tower cylinder section, and then the clamping plate in the lower ring is clamped on the lower tower cylinder section, so that the upper and lower tower cylinder sections can be gradually aligned, thereby improving the docking efficiency. At the same time, the number of clamping plates used can also be adjusted to facilitate the clamping of tower cylinder sections of different sizes and models, thereby improving versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the size structure of the tower after welding numbered C2202 of the present invention.

[0028] Figure 2 This is a schematic diagram of the size structure of the tower after welding numbered C2204 of the present invention.

[0029] Figure 3 This is a schematic diagram of the size structure of the tower after welding numbered C2205 of the present invention.

[0030] Figure 4 It is a schematic structural diagram of the assembly fixture of the present invention.

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

[0032] Figure 6 It is a schematic diagram of the sliding frame and related internal structures of the present invention.

[0033] Figure 7 It is a schematic diagram of the array structure of each push plate and slide seat of the present invention.

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

[0035] In the figure: 1, hanger; 2, sleeve ring; 3, connecting seat; 4, slide frame; 5, two-way telescopic rod 1; 6, top ring; 7, slide seat; 8, turn plate; 9, clamping plate; 10, bolt hole; 11, slide groove; 12, slider; 13, slide rail; 14, guide block; 15, guide slide rod; 16, spring 1; 17, T-block; 18, inclined block; 19, mounting seat; 20, two-way telescopic rod 2; 21, ring; 22, push plate. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

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

[0038] S1: performing groove processing on at least two tower barrel sections to be assembled, making an assembly fixture, positioning the tower barrel section in the air, and installing the assembly fixture, adjusting the mating orientation of the tower barrel section by the assembly fixture, and then assembling and fixing the tower barrel section;

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

[0040] S2: arc welding is used to weld the gap between the tower cylinder sections after the assembly is fixed. Specifically, multiple sections of welding are carried out simultaneously. Before the multiple sections of welding are carried out, spot welding is first carried out in the groove. After the welding is completed, a circumferential weld is formed.

[0041] S3: Check the stability of the girth welds at the connection of the two tower cylinder sections. If the inspection is qualified, the two tower cylinder sections will be heat treated. If it is unqualified, it will be reinforced and then heat treated. The stability check specifically combines the actual compressive stress of the girth weld with the allowable stress to obtain the safety factor for analysis and judgment.

[0042] The stability check is as follows:

[0043] Obtain the compressive stress σ of the upper end cylinder of the girth weld on the girth weld 1 , wind load compressive stress σ on girth weld 2 ;

[0044] σ 压 =σ 1+ σ 2

[0045] Safety factor K = B / σ 压

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

[0047] In step S3, the tower barrel section is lifted and stabilized by using a crane hook, and the center of the hook is ensured to coincide with the center of the tower barrel section. The load of the crane is 0.95-1.05 times the weight of the upper tower barrel section.

[0048] See also Figure 4-7 The present invention provides a technical solution: the assembly fixture in S1 includes a hanger 1, the hanger 1 is connected with two layers of collars 2 for clamping the upper and lower tower barrel sections, and the inner side of the collar 2 is connected with a plurality of slide frames 4 in an array, such as Figure 4 As shown, the hanger 1 is sleeved on the outside of the collar 2, and the collar 2 is arranged in two symmetrical layers in the hanger 1.

[0049] Slide seats 7 are slidably connected to both sides of the slide frame 4, and a rotating plate 8 is rotatably connected to each slide seat 7, and a clamping plate 9 is rotatably connected to the rotating plate 8. A T-shaped block 17 is slidably connected to the slide seat 7. Figure 5 As shown, the upper and lower slide seats 7 can slide towards or away from each other, thereby driving the clamping plates 9 arranged in the circumferential array to move synchronously to disperse or gather with each other.

[0050] The collar 2 is connected to a two-way telescopic rod 20, and a push plate 22 is connected to the two-way telescopic rod 20. The push plate 22 slides in contact with 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 and extend to the outside of the slide frame 4 to move away from each other. Figure 5 , 6 As shown in Figure 7, the push plates 22 on the upper and lower sides can be driven to approach each other by contracting the bidirectional telescopic rod 20, and the sliders 17 that slide in the slide seat 7 on their respective sides slide in close contact, so that the slider 17 that was originally on the radial inner side of the slide frame 6 along the collar 2 is pushed to the outside, and then the slide seats 7 on the upper and lower sides can be driven away from each other by the driving mechanism, so as to drive the clamping plates 9 to gather together and clamp the tower cylinder section therein.

[0051] The inner array of the collar 2 is fixedly connected with a plurality of connecting seats 3, and is connected to the slide frame 4 through the connecting seats 3. The inner walls of both sides of the slide frame 4 are provided with slide grooves 11. Both sides of the slide seat 7 are connected with sliders 12, and the sliders 12 are slidably connected in the slide grooves 11. Figure 2 As shown, the setting of the connecting seat 3 allows the slide frame 4 to be connected thereto and be located on the inner side of the collar 2, which is convenient for setting a driving mechanism on the collar 2. At the same time, the sliding cooperation between the slide groove 11 and the slider 12 can stabilize the sliding of the upper and lower slide seats 7 in the slide frame 4.

[0052] The slide seat 7 is connected to a slide rail 13, and the slide block 17 is connected to a guide block 14. The guide block 14 is slidably connected to the slide rail 13. The inner wall of the slide rail 13 is connected to a guide slide rod 15. The guide block 14 is slidably sleeved on the outer side of the guide slide rod 15. The outer side of the guide slide rod 15 is sleeved with a spring 16. The two ends of the spring 16 are respectively connected to the slide rail 13 and the guide block 14. Figure 6 As shown, the setting of the guide slide rod 15 makes the sliding of the guide block 14 in the slide rail 13 more stable, and the setting of the spring 16 makes it possible for the spring 16 to push the guide block 14 in the absence of external force, thereby driving the slider 17 to slide radially inwardly of the collar 2 and be located on 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 close contact with the slider 17 through the inclined block 18, so that the push plate 22 can be pushed by the cooperation with the inclined block 18, and indirectly push the slider 17 to slide to the outside of the slide frame 4, thereby improving the smoothness of the cooperation and sliding between each other.

[0053] The inner side of the ring 2 is connected to a mounting seat 19, a two-way telescopic rod 20 is embedded in the mounting seat 19, and the two ends of the two-way telescopic rod 20 are located at the upper and lower sides of the ring 2 and connected to a ring 21. Each push plate 22 is a group of three, and the push plates 22 in the group are connected to the ring 21 in an array with gradually shortened lengths, such as Figure 5 , 7 As shown, the installation of the mounting seat 19 facilitates the installation of the two-way telescopic rod 20 inside the collar 2, and enables the two-way telescopic rod 20 to be located inside the slide frame 4. The setting of the ring 21 can drive each group of push plates 22 to move downward synchronously. At the same time, since each group of push plates 22 is set to three and the length is gradually shortened, Figure 7 It can be seen from the figure that there are actually 12 push plates 22, which means there are four groups. When the two-way telescopic rod 20 contracts and drives the two side rings 21 to approach each other, it will first drive the longest push plate 22 in each group to fit with the inclined block 18, so as to push and slide the slider 17. At this time, one push plate 22 in each group of push plates 22 will first fit with the inclined block 18 to slide, that is, first push the slider 17 on the slide seat 7 in the four slide frames 4 to slide, and as the two-way telescopic rod 20 continues to contract, it will again drive the second longest push plate 22 in each group to fit with the inclined block 18 to slide, and so on, it is possible to adjust the number of sliders 17 sliding out of the slide frame 4 through the degree of contraction of the two-way telescopic rod 20, and facilitate the operation of the driving mechanism, thereby driving 4, 8 or 12 clamps to gather synchronously to adjust and clamp tower cylinder sections of different sizes.

[0054] Furthermore, the number of the push plates 22 is the same as the number of the slide frames 4 and they are synchronously arranged, and the length of each group of push plates 22 changes in the same direction along the circumferential direction of the collar 2 .

[0055] The driving mechanism includes a bidirectional telescopic rod 5 and a top ring 6. The bidirectional telescopic rod 5 is embedded in the ring 2 and extends to the upper and lower sides of the ring 2 respectively. The top rings 6 are connected to the extended ends. The top rings 6 on the upper and lower sides respectively cooperate with the sliders 17 on the upper and lower sides. Figure 5 As described above, when the two-way telescopic rod 20 contracts 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 driving mechanism can be started, that is, the two-way telescopic rod 15 is controlled to extend, so that the top rings 6 on the upper and lower sides can be pushed away from each other, and the slider 17 is pushed on the slide frame 4 along the radial outer end of the collar 2 to drive the slide seats 7 on the upper and lower sides to move away from each other, and then the clamping plate 9 is driven to gather through the rotating plate 8 to clamp the middle tower cylinder section.

[0056] The two ends of the rotating plate 8 are rotatably connected with the slide seat 7 and the clamping plate 9 through a scroll hinge. A spring 2 is also arranged in the slide groove 11. The two ends of the spring 2 are connected with the slide groove 11 and the slider 12. Bolt holes 10 are also opened on the clamping plate 9. Bolts are arranged in the bolt holes 10. The clamping plate 9 is installed with a heating device through bolts. Scroll hinges are arranged at both ends of the rotating plate 8. The scroll hinge forces at both ends of the rotating plate 8 can drive the upper and lower slide seats 7 to have a tendency to approach each other in the slide frame 4, so that when the driving mechanism is not running, the upper and lower slide seats 7 can be in a state of approaching each other, thereby driving each clamping plate 9 to move away from each other and disperse, so as to facilitate the clamping operation on the outer side of the tower cylinder section. The setting of the spring 2 can also further assist the upper and lower slide seats 7 to approach each other. A heating device can also be installed on the clamping plate 9 through bolts, so that when the high-altitude ring weld is heat treated, it can be directly carried out through the heating device installed on the clamping plate 9.

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

[0058] When checking the stability of the girth weld according to the factors affecting wind load, the specific method is as follows:

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

[0060] σ 1 =155000×9.8 / (3.14×4×0.055)=2.199Mpa;

[0061] (2): Influence of wind load:

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

[0063] P i =K 1·K 1 i·q 。 ·f i ·L i ·d 0 i

[0064] Where:

[0065] <![CDATA[K 1 :Body shape coefficient (take 0.7)]]> <![CDATA[q 。 :The basic wind pressure value of the place (take 410N / m 2 )—According to the design drawings]]> <![CDATA[f i :Wind pressure height change value]]> <![CDATA[L i :The first section calculates the height]]> <![CDATA[K 1 i: Wind vibration coefficient of the calculation section, when the height H≤20m, take 1.7]]>

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

[0067] (K 1 i=1+ξ·V i ·φ 2 i / f i )

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

[0069] Vi pulse influence coefficient;

[0070] φzi vibration coefficient;

[0071] (3) Figure 1 For example, the C2202 tower of K 1 The wind vibration coefficient of the calculation section i is calculated:

[0072] 1) Calculate q1·T1 2 value:

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

[0074] T1 self-oscillation period S0;

[0075]

[0076] m 0 —Total mass of calculation section (Kg) m 0 =155000Kg;

[0077] H—Calculation section straight section height (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 get ξ=2.1945;

[0084] 2) Calculation of Vi:

[0085] Section 1: According to Hit = 50.412, for Class B areas, look up Table 14-6, Vi1 = 0.8656;

[0086] Section 2: According to Hit = 61.626M, for Class B areas, look up Table 14-6, Vi2 = 0.8808;

[0087] 3) Calculation of φzi:

[0088] Section 1: According to Hit / H=50.412 / 66.54=0.7576, u=1, look up Table 14-7, φzi=0.6749;

[0089] Section 2: According to Hit / H=61.626 / 66.54=0.9261, u=1, look up 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 with the number C2202, control weight G is 155T, and conduct feasibility analysis on the upper section butt weld of the tower tube section. The upper section is divided into two sections according to its shape characteristics, and the wind pressure and bending moment are calculated:

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

[0095] L 1 =11m,d 0i =4.11m, H 1 =5.5m, the top cross section is 55.912m above the ground. According to the relevant data, the f i =1.73;

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

[0097] Bending distance of wind on girth weld: M 1 =P 1 ·H 1 =39080.6×5.5=214943.3 (N·M); (2) Second section cylinder: (55.912-66.54m)

[0098] L 2 =11.428m, d 0i =4.11m, H 2 =16.714m, the height of its top cross section from the ground is 66.54m, according to the relevant data, the f of the cylinder i =1.83;

[0099] Wind pressure P 2 =0.7×1.955×410×1.83×11.428×4.11=48227.2N;

[0100] Bending distance of wind on girth weld: M 2 =P 2 ·H 2 =48227.2×16.714=806069.4(N·M);

[0101] (3) Total bending distance of the wind-on circumferential weld: M 风 =M 1 +M 2 =1021012.7(N·M);

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

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

[0104] (5) The moment of inertia I and the bending moment section coefficient W of the girth weld cross section are:

[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 that the wind bending moment and the eccentric bending moment are concentric, the maximum pressure generated by the bending moment is: 2 =(M 风 +M 偏 ) / W=1.524Mpa;

[0108] Therefore, the actual compressive stress of the girth weld is:

[0109] σ 压 =σ 1 +σ 2 =2.199+1.524=3.723Mpa.

[0110] 2. Please refer to Figure 2 , provide the welded tower with the number C2204, control weight G is 65T, and conduct feasibility analysis on the upper section butt weld of the tower tube section. The upper section is divided into three sections according to its shape characteristics, and the wind pressure and bending moment are calculated:

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

[0112] L 1 =11.4m,d 0i =3.932m, H 1 =5.7m, the top cross section is 57.223m above the ground. According to the 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] Bending distance of wind on girth weld: M 1 =P 1 ·H 1 =38277.6×5.7=218182.3(N·M);

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

[0116] L 2 =9m,d 0i =2.624m, H 2 =15.9m, the height of its top cross section from the ground is 66.223m, according to the relevant data, the f of the cylinder i =1.82;

[0117] Wind pressure: P 2 =0.7×1.9×410×1.82×9×2.624=23437.6N;

[0118] Bending distance of wind on girth weld: M 2 =P 2 ·H 2 =23437.6×15.9=372658(N·M);

[0119] (3) The third cylinder: (75.48m-66.223m)

[0120] L 3 =9.257m,d 0i =2.624m, H 3 =25.03m, and the height of its top cross section from the ground is 75.48m. i =1.91;

[0121] Wind pressure: P 3 =0.7×2.05×410×1.91×9.257×2.624=27296.2N;

[0122] Bending distance of wind on girth weld: M 3 =P 3 ·H 3 =27296.2×25.03=683223.9(N·M);

[0123] (4) Total bending distance of the wind-on circumferential weld: M 风 =M 1 +M 2 +M 3 =1274064.2(N·M);

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

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

[0126] (6) The moment of inertia I and the bending moment section coefficient W of the girth weld cross section are:

[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 that the wind bending moment and the eccentric bending moment are concentric, the maximum pressure generated by the bending moment is: 2 =(M 风 +M 偏 ) / W=15.12Mpa;

[0130] Therefore, the actual compressive stress of the girth weld is:

[0131] σ 压 =σ1 +σ 2 =3.25+15.12=18.37Mpa.

[0132] 3. Please refer to Figure 3 , provide the welded tower with the number C2205, control the weight G to 65T, and conduct feasibility analysis on the upper section butt weld of the tower tube section. The upper section is divided into two sections according to its shape characteristics, and the wind pressure and bending moment are calculated:

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

[0134] L 1 =10m,d 0i =3.73m, H 1 =5m, the top cross section is 45.85m above the ground. According to the 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] Bending distance of wind on girth weld: M 1 =P 1 ·H 1 =31164×5=155820(N·M);

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

[0138] L 2 =8.86m, d 0i =3.73m, H 2 =9.43m, the top cross section is 54.71m above the ground, and the f of the cylinder is i =1.72;

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

[0140] Bending distance of wind on girth weld: M 2 =P 2 ·H 2 =33084×9.43=311982(N·M);

[0141] (3) Total bending distance of the wind-on circumferential weld: M 风 =M 1 +M 2 =467802(N·M);

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

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

[0144] (5) The moment of inertia I and the bending moment section coefficient W of the girth weld cross section are:

[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 that the wind bending moment and the eccentric bending moment are concentric, the maximum pressure generated by the bending moment is: 2 =(M 风 +M 偏 ) / W=2.82Mpa;

[0148] Therefore, the actual compressive stress of the girth weld is:

[0149] σ 压 =σ 1 +σ 2 =3.43+2.82=6.25Mpa.

[0150] 4. The allowable stress is the smaller value of the calculation results in the following formula:

[0151]

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

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

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

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

[0156] 09MnNiRD takes the minimum value: B = 97.96;

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

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

[0159] The upper ring weld of C2205 is 6.25mPa, so the safety factor K=B / σ 压 =25.9 / 6.25=4.144;

[0160] C2201 is not calculated because its wall thickness and material are similar to C2202 and better than C2205.

[0161] Conclusion: C2202 does not require reinforcement due to its thicker wall, larger section inertia moment I and bending section coefficient W; C2205 and C2204 require crane stabilization measures and heat treatment to ensure safety.

[0162] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for aerial assembly and heat treatment of chemical towers, characterized in that: The following steps are involved: S1: performing groove processing on at least two tower barrel sections to be assembled, making an assembly fixture, positioning the tower barrel section in the air, and installing the assembly fixture, adjusting the mating orientation of the tower barrel section by the assembly fixture, and then assembling and fixing the tower barrel section; S2: arc welding is used to weld the gap between the tower cylinder sections after the assembly is fixed. Specifically, multiple sections of welding are carried out simultaneously. Before the multiple sections of welding are carried out, spot welding is first carried out in the groove. After the welding is completed, a circumferential weld is formed. S3: Perform a stability check on the girth weld at the connection between the two tower cylinder sections. If the check is qualified, the two tower cylinder sections will be heat treated. If it is unqualified, they will be reinforced and then heat treated. The stability check specifically combines the actual compressive stress on the girth weld with the allowable stress to derive a safety factor for analysis and judgment.

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

3. The method for aerial assembly and heat treatment of chemical towers according to claim 1, characterized in that: The stability check is specifically as follows: Obtain the compressive stress σ1 of the upper end cylinder section of the girth weld on the girth weld and the compressive stress σ2 of the wind load on the girth weld; s 压 =s 1+ p2 Safety factor K = B / σ 压 Among them, B is the allowable stress of the tower cylinder section.

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

5. The method for aerial assembly and heat treatment of chemical towers according to claim 1, characterized in that: The assembly fixture described in S1 comprises a hanger (1), wherein the hanger (1) is internally connected with two layers of sleeves (2) for clamping the upper and lower tower barrel sections, wherein the sleeves (2) are internally connected with a plurality of slide frames (4) in an array, wherein both sides of the slide frames (4) are slidably connected with slide seats (7), wherein each of the slide seats (7) is rotatably connected with a rotating plate (8), and wherein the rotating plate (8) is rotatably connected with a clamping plate (9), wherein the slide seats (7) are slidably connected with a T-shaped block (17), wherein the sleeve (2) is connected with a two-way telescopic rod (20), and a push plate (22) is connected with the T-shaped block (17) through the two-way telescopic rod (20), wherein the push plate (22) is fitted and slid with the T-shaped block (17) to push the T-shaped block (17) to slide radially outwardly along the sleeve (2), and wherein a driving mechanism is provided on the sleeve (2) for driving the T-shaped blocks (17) that slide and extend to the outside of the slide frames (4) to move away from each other.

6. The method for aerial assembly and heat treatment of chemical towers according to claim 5, characterized in that: The inner array of the collar (2) is fixedly connected to a plurality of connection seats (3), and is connected to the slide frame (4) via the connection seats (3); both inner walls of the slide frame (4) are provided with slide grooves (11); both sides of the slide seat (7) are connected to sliders (12), and the sliders (12) are slidably connected in the slide grooves (11).

7. The method for aerial assembly and heat treatment of chemical towers according to claim 6, characterized in that: The slide seat (7) is connected to a slide rail (13), the T-shaped block (17) is connected to a guide block (14), the guide block (14) is slidably connected in the slide rail (13), the inner wall of the slide rail (13) is connected to a guide slide rod (15), the guide block (14) is slidably sleeved on the outer side of the guide slide rod (15), the outer side of the guide slide rod (15) is sleeved with a spring 1 (16), the two ends of the spring 1 (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), and the push plate (22) slides in contact with the T-shaped block (17) through the inclined block (18).

8. The method for aerial assembly and heat treatment of chemical towers according to claim 6, characterized in that: The inner side array of the sleeve ring (2) is connected to a mounting seat (19), the two-way telescopic rod (20) is embedded in the mounting seat (19), and the two ends of the two-way telescopic rod (20) are located at the upper and lower sides of the sleeve ring (2) and are connected to a circular ring (21), and each push plate (22) is a group of three, and the push plates (22) in the group are connected to the circular ring (21) in an array with gradually shortened lengths.

9. The method for aerial assembly and heat treatment of chemical towers according to claim 6, characterized in that: The driving mechanism comprises a bidirectional telescopic rod (5) and a top ring (6). The bidirectional telescopic rod (5) is embedded in the sleeve ring (2) in an array and extends to the upper and lower sides of the sleeve ring (2) respectively, and the top ring (6) is connected to the extended ends. The top rings (6) on the upper and lower sides respectively cooperate with and abut against T-shaped blocks (17) on the upper and lower sides.

10. The method for aerial assembly and heat treatment of chemical towers according to claim 6, characterized in that: Both ends of the rotating plate (8) are rotatably connected to the sliding seat (7) and the clamping plate (9) through scroll hinges. A second spring is also arranged in the sliding groove (11). Both ends of the second spring are connected to the sliding groove (11) and the sliding block (12). A bolt hole (10) is also opened on the clamping plate (9). A bolt is arranged in the bolt hole (10). The clamping plate (9) is installed with a heating device through the bolts.

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