Positioning method for large-scale air separation engineering cold box horizontal assembly tower

Abstract

The present application relates to a kind of positioning method of large-scale air separation engineering cold box horizontal assembly tower, comprising the following steps: step one: tower support blanking;Step two: tower support group is matched;Step three: tower support welding;Step four: tower support installation, adjustment;Step five: tower hoisting in place;Step six: tower circumference direction adjustment;Step seven: tower horizontal measurement.The present application utilizes the blanking, group is matched, welding, installation adjustment, hoisting in place, adjustment and other series of steps of tower support, effectively improves the positioning adjustment efficiency of tower, solves the technical problem of large-scale tower installation and positioning under the condition that construction space is limited, improves construction efficiency, and guarantees construction quality.

Description

Technical Field

[0001] The invention relates to the technical field of installation and positioning of a horizontal assembly tower of a large-scale air separation project cold box, and in particular to a positioning method of a horizontal assembly tower of a large-scale air separation project cold box. Background Art

[0002] Large-scale air separation projects are large-scale industrial devices that use air as raw material and separate oxygen and nitrogen in the air under a cryogenic state (-196℃). They are important public auxiliary energy media systems in the steel, chemical, petrochemical and other industries. They can also supply medical liquid oxygen, rare gases, etc. The cold box is the core device of the air separation project. The cold box consists of steel structure, tower, pipeline, instrumentation, etc., with a height of more than 60 meters. With the continuous advancement of technology, the supply of cold boxes has become diversified, including integral skid-mounted, split skid-mounted, bulk, on-site horizontal assembly, etc. The tower equipment in the cold box is heavy (50,000 Nm 3 / h air separation unit as an example, it weighs about 120t), has a large volume (Φ3700×64000mm), is high (about 64m), has a small space in the cold box, and has many high-altitude operations, which poses great safety risks. The tower is assembled horizontally on site and hoisted vertically into place, which minimizes the safety risks of high-altitude operations and reduces the use of large cranes.

[0003] Since horizontal cold box assembly is performed at room temperature and operation is performed in a vertical cryogenic state, the quality of tower assembly and positioning is crucial. This is affected by factors such as the assembly site, weather, confined space, the quality of cold box frame assembly, and the quality of tower support fabrication and installation. Tower assembly and adjustment methods are a key technical challenge in ensuring cold box operation quality. Therefore, it is necessary to develop a method for positioning towers for horizontal cold box assembly in large-scale air separation plants to address the technical challenges of horizontal cold box tower assembly and adjustment under limited construction space. This is of great significance for ensuring cold box assembly safety and improving construction efficiency. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a positioning method for a horizontal assembly tower of a cold box in a large air separation project. By utilizing a series of steps such as cutting, assembling, welding, installing and adjusting the tower bracket, hoisting the tower into place, and adjusting the tower, the positioning and adjustment efficiency of the tower is effectively improved, the technical difficulties in installing and positioning large towers under conditions of limited construction space are solved, the construction efficiency is improved, and the construction quality is guaranteed.

[0005] The technical solution adopted by the present invention to solve the technical problem is: to provide a positioning method for a horizontal assembly tower of a cold box in a large air separation project, comprising the following steps:

[0006] Step 1: Cutting the tower support;

[0007] The tower support is composed of 9 stainless steel pipe sections, a web with 8 holes, a bottom plate, an arc support plate, a side plate and 5 pairs of reinforcing ribs. The 9 stainless steel pipe sections are composed of 5 columns and 4 symmetrical diagonal braces. The 8 holes of the web are symmetrically distributed. The radius of the arc support plate matches the radius of the tower at the corresponding position.

[0008] Step 2: Assemble the tower supports;

[0009] Before welding the bracket, check the dimensional deviation of the prefabricated components according to the design drawings, standards and specifications, remove the slag, splash, sand and oil stains in and around the groove, design and make the tower bracket assembly welding tooling platform, quickly assemble the bracket, check the bracket assembly quality, and perform spot welding after meeting the requirements;

[0010] The quality of the bracket assembly includes the curvature of the arc support plate, the spacing between the five stainless steel risers, the length and width of the side panels, and the angle of the ribs;

[0011] Step 3: Tower bracket welding;

[0012] Welding parameters are strictly selected according to welding process assessment. Welding adopts submerged arc welding or manual arc welding symmetrical welding process. After welding, slag and spatter are removed in time and weld appearance inspection is carried out.

[0013] Step 4: Install and adjust the tower bracket;

[0014] After the cold box frame is assembled and leveled, the tower bracket is installed. A laser collimator is used to measure the bracket centerline. The vertical installation coordinates in the drawing are converted into horizontal installation coordinates. The center point is marked on the frame beam where the bracket is located. The tower bracket is then installed in place so that the bracket center point coincides with the marked center. The levelness of the saddle-type bracket is checked. If it meets the requirements, the bracket and the measured spot are welded. The levelness is re-combined. After confirmation, the bracket and the beam are welded. After welding is completed, Teflon isolation gaskets are laid on the arc support plate.

[0015] There are a total of 8 tower supports. After all are installed, adjusted, and spot-welded, confirm again that the curvature of the arc support plate matches the radius of the tower and that the center line of the support is on the center line of the tower frame before welding. The welding should be symmetrical, and deformation control should be strengthened during the process. After the welding is completed, there should be no twisting or deformation. The size of the Teflon isolation gasket should cover the entire arc support plate.

[0016] Step 5: Hoist the tower into place;

[0017] The main tower weighs 120 tons and is 63.7 meters long. Two 500t truck cranes were used to lift it into place. Each lifting sling weighs 0.5 tons, and each crane hook weighs 1.5 tons. The total lifting weight is 124 tons. Considering the dynamic load factor of 1.1, the lifting weight is 136.5 tons, and each crane bears 68.25 tons. Two 16-meter-long 50t round slings are used, each with two strands. The standard lifting sling U-shaped 0°-7° has a lifting factor of 2.0. The allowable force at each crane lifting point is 50t*2=100t>68.25t.

[0018] Step 6: Adjust the circumferential direction of the tower;

[0019] Hang two plumb bobs from the 0° mark on the bottom of the tower, and hang a plumb bob from the 0° mark downward. Rotate the tower until the plumb bobs on both sides of the tower are the same size as the plumb bob at 0°.

[0020] Step 7: Tower level measurement;

[0021] Hang a plumb bob from the 0° position on all final assembly sealing welds along the length of the tower and measure the distance from the plumb bob to the left front corner main beam. The maximum error per linear meter at all positions should not exceed 1.3mm, and the maximum error of the total length of the cold box is 12.7mm;

[0022] Adjust the instrument to a horizontal state, use X-ray to measure the 90° mark points of all closed welds on the tower body, and measure the distance from the plumb bob to the left front corner main beam. At all positions, the maximum error per linear meter should not exceed 1.3mm, and the maximum error of the total length of the cold box is 12.7mm.

[0023] As a supplement to the technical solution described in the present invention, in step 2, the direction of the ribs points to the center of the tower, the middle rib is in a vertical state, and the angles of the remaining ribs are 15° and 30° with the middle rib, and are symmetrically distributed on both sides of the middle rib.

[0024] As a supplement to the technical solution described in the present invention, in step four, the tower bracket is installed after determining that the assembly level of the cold box frame is adjusted within the range of ±3mm, and the level of the saddle-type bracket is within the range of ±3mm.

[0025] As a supplement to the technical solution described in the present invention, in the step 5, the tower is hoisted into place based on the base on which the tower is located after the air separation tower is installed in place, there is no gap between the tower and the base, and the circumferential direction is based on the 0° mark direction.

[0026] As a supplement to the technical solution described in the present invention, in step six, a jack support bracket is welded on the tower guard plate, and the tower angle is slowly and slightly adjusted by adjusting the jack to make the tower slowly suspend for tower adjustment.

[0027] As a supplement to the technical solution described in the present invention, in step seven, the tower level is measured with the left front corner main beam as a reference, and the distance between the plumb bob and the main beam is measured.

[0028] As a supplement to the technical solution described in the present invention, the tower bracket is a saddle-type seat, a plasma cutting machine is used to cut the stainless steel plate, and a blanking template is used for marking and cutting to ensure that the cutting size deviation meets the standard specification requirements, the edges of the components are polished and smooth, and impurities that affect welding are cleaned. The weld groove adopts a V-shaped groove, and the V-shaped groove angle is 55-65°.

[0029] Beneficial effects: The present invention relates to a positioning method for a horizontal assembly tower of a cold box in a large-scale air separation project, which innovates the positioning method for a horizontal assembly tower of a cold box in a large-scale air separation project. By utilizing a series of steps such as cutting, assembling, welding, installing and adjusting the tower bracket, hoisting and adjusting the tower, the positioning and adjustment efficiency of the tower is effectively improved, the technical difficulties in installing and positioning large towers under conditions of limited construction space are solved, the construction efficiency is improved, and the construction quality is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the double-click lifting of the tower of the present invention;

[0031] Figure 2 It is a schematic diagram of tower installation of the present invention;

[0032] Figure 3 It is a schematic diagram of the circumferential direction adjustment of the tower of the present invention;

[0033] Figure 4 It is a schematic diagram of measuring the horizontality of a tower according to the present invention.

[0034] Illustration: 1. Stainless steel pipe section, 2. Web plate, 3. Bottom plate, 4. Arc support plate, 5. Side plate. DETAILED DESCRIPTION

[0035] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0036] The embodiment of the present invention relates to a positioning method for a horizontal assembly tower of a large air separation cold box, such as Figure 1-4 As shown, the following steps are included:

[0037] Step 1: Cutting the tower support;

[0038] The tower (horizontally installed) bracket is a saddle-shaped seat with a special-shaped structure made of stainless steel. A plasma cutting machine is used to cut the stainless steel plate, and a blanking template is used for marking and blanking to ensure that the dimensional deviation of the cutting meets the requirements of the standard specifications. The edges of the components should be polished and smooth, and impurities that affect welding should be cleaned. The weld groove adopts a V-shaped groove.

[0039] The tower support is composed of 9 stainless steel pipe sections 1, a web 2 with 8 holes, a bottom plate 3, an arc support plate 4, a side plate 5 and 5 pairs of reinforcing ribs. The 9 stainless steel pipe sections 1 are composed of 5 columns and 4 symmetrical diagonal braces. The 8 holes of the web 2 are symmetrically distributed. The radius of the arc support plate 4 matches the radius of the tower at the corresponding position. The V-groove angle is 55-65°.

[0040] Step 2: Assemble the tower supports;

[0041] Before welding the bracket, check the dimensional deviation of the prefabricated components according to the design drawings, standards and specifications, remove the slag, splash, sand and oil stains in and around the groove, design and make the tower bracket assembly welding tooling platform, quickly assemble the bracket, check the bracket assembly quality, and perform spot welding after meeting the requirements;

[0042] The quality of the bracket assembly includes the curvature of the arc support plate 4, the spacing between the five stainless steel risers, the length and width of the side plate 5, the angle of the rib plate, etc.

[0043] Step 3: Tower bracket welding;

[0044] Welding parameters are strictly selected in accordance with welding process assessment. Welding adopts submerged arc welding or manual arc welding symmetrical welding process. Slag and spatter must be removed promptly after welding. The weld appearance must be inspected to ensure that there are no quality defects such as slag, spatter, cracks, slag inclusions, pores, arc pits, undercuts, etc.

[0045] Step 4: Install and adjust the tower bracket;

[0046] After the cold box frame is assembled and the levelness is adjusted, the tower bracket is installed. A laser collimator is used to measure the bracket centerline. The vertical installation coordinates in the drawing are converted into horizontal installation coordinates. The center point is marked on the frame beam where the bracket is located. The tower bracket is then installed in place so that the bracket center point coincides with the marked center. The levelness of the saddle-type bracket is checked. If it meets the requirements, the bracket and the measured spot are welded. The levelness is re-combined. After confirmation, the bracket and the beam are welded. After welding is completed, Teflon isolation gaskets are laid on the arc support plate 4.

[0047] There are eight tower supports in total. After all are installed, adjusted, and spot-welded, confirm again that the curvature of the arc support plate 4 matches the tower radius and that the centerline of the support is on the centerline of the tower frame before welding. The welding should be symmetrical, with strict control of deformation during the process. After welding is completed, there should be no twisting or deformation. The Teflon isolation gasket should be large enough to cover the entire arc support plate 4.

[0048] Step 5: Hoist the tower into place;

[0049] The main tower weighs approximately 120 tons and is 63.7 meters long. Two 500t truck cranes were used for dual-machine lifting and hoisting into place. Each sling weighs approximately 0.5 tons, and each crane hook weighs 1.5 tons. The total hoisting weight is 124 tons (equipment weight + 2×slings + 2×crane hooks). Considering a dynamic load factor of 1.1, the hoisting weight is 136.5 tons, with each crane bearing 68.25 tons. Two 16-meter-long 50t round slings, each with two strands, are used. The standard hoisting sling has a U-shaped 0°-7° angle and a hoisting factor of 2.0. Therefore, the allowable force at each crane lifting point is 50t*2=100t, which is greater than 68.25t (the equipment weight borne by each crane sling during lifting).

[0050] Step 6: Adjust the circumferential direction of the tower;

[0051] Hang two plumb bobs from the 0° mark on the bottom of the tower, and hang a plumb bob from the 0° mark downward. Rotate the tower until the plumb bobs on both sides of the tower are the same size as the plumb bob at 0°.

[0052] Step 7: Tower level measurement;

[0053] Hang a plumb bob from the 0° position on all final assembly seal welds (circumferential welds) along the length of the tower. Measure the distance from the plumb bob to the left front corner main beam. At all locations, the maximum error should not exceed 1.3mm per linear meter (1 / 64in per linear foot) and the maximum error for the total length of the cold box is 12.7mm (1 / 2in);

[0054] Adjust the instrument to a horizontal position and use a radiograph to measure the 90° (or 270°) mark on all closed welds of the tower. Measure the distance from the plumb bob to the left front corner main beam. At all locations, the maximum error per linear meter should not exceed 1.3mm, and the maximum error for the total length of the cold box should be 12.7mm.

[0055] In the step 2, the direction of the ribs points to the center of the tower, the middle rib is vertical, and the angles of the remaining ribs with the middle rib are 15° and 30°, and they are symmetrically distributed on both sides of the middle rib.

[0056] In the step 4, the tower support is installed after the horizontality of the cold box frame assembly is determined to be adjusted within the range of ±3mm (1 / 8in). The horizontality of the saddle-type support is within the range of ±3mm (1 / 8in).

[0057] In the step 5, the tower is hoisted into place based on the base on which the tower is located after the air separation tower is installed in place, with no gap between the tower and the base, and the circumferential direction is based on the 0° mark direction.

[0058] In the step six, a jack support bracket is welded to the tower guard plate, and the tower angle is slowly and slightly adjusted by adjusting the jack to make the tower slowly suspend to adjust the tower.

[0059] In step seven, the tower level is measured with the left front corner main beam as the reference, and the distance between the plumb bob and the main beam is measured.

[0060] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0061] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0062] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0063] The positioning method of the large-scale air separation engineering cold box horizontal assembly tower provided by the application is described in detail in the above, and the principles and implementation manners of the application are described by using specific examples in the text. The above example description is only used to help understand the method of the application and its core idea; at the same time, for those skilled in the art, according to the idea of the application, the specific implementation manners and application ranges will be changed, and the above is not understood as a limitation on the application.

Claims

1. A positioning method for a horizontal assembly tower of a large-scale air separation cold box, characterized by: The following steps are involved: Step 1: Cutting the tower support; The tower support is composed of 9 stainless steel pipe sections (1), a web (2) with 8 holes, a bottom plate (3), an arc support plate (4), a side plate (5) and 5 pairs of reinforcing ribs. The 9 stainless steel pipe sections (1) are composed of 5 columns and 4 diagonal braces symmetrical in pairs. The 8 holes of the web (2) are symmetrically distributed. The radius of the arc support plate (4) matches the radius of the tower at the corresponding position. Step 2: Assemble the tower supports; Before welding the bracket, check the dimensional deviation of the prefabricated components according to the design drawings, standards and specifications, remove the slag, splash, sand and oil stains in and around the groove, design and make the tower bracket assembly welding tooling platform, quickly assemble the bracket, check the bracket assembly quality, and perform spot welding after meeting the requirements; The quality of the bracket assembly includes the curvature of the arc support plate (4), the spacing between the five stainless steel risers, the length and width of the side plate (5), and the angle of the rib plate; Step 3: Tower bracket welding; Welding parameters are strictly selected according to welding process assessment. Welding adopts submerged arc welding or manual arc welding symmetrical welding process. After welding, slag and spatter are removed in time and weld appearance inspection is carried out. Step 4: Install and adjust the tower bracket; After the cold box frame is assembled and the levelness is adjusted, the tower bracket is installed. A laser collimator is used to measure the center line of the bracket. The vertical installation coordinates in the drawing are converted into horizontal installation coordinates. The center point is marked on the frame beam where the bracket is located. The tower bracket is then installed in place so that the center point of the bracket coincides with the center of the mark. The levelness of the saddle-type bracket is checked. If it meets the requirements, the bracket and the beam are spot welded. The levelness is checked again. After confirming that it is correct, the bracket and the beam are welded. After the welding is completed, a Teflon isolation gasket is laid on the arc support plate (4); There are a total of 8 tower supports. After all are installed, adjusted, and spot-welded, it is confirmed again that the curvature of the arc support plate (4) matches the radius of the tower and the center line of the support is on the center line of the tower frame before welding. The welding should be symmetrical, and deformation control should be strengthened during the process. After the welding is completed, there is no twisting or deformation. The size of the Teflon isolation gasket covers the entire arc support plate (4). Step 5: Hoist the tower into place; The main tower weighs 120 tons and is 63.7 meters long. Two 500t truck cranes were used to lift it into place. Each lifting sling weighs 0.5 tons, and each crane hook weighs 1.5 tons. The total lifting weight is 124 tons. Considering the dynamic load factor of 1.1, the lifting weight is 136.5 tons, and each crane bears 68.25 tons. Two 16-meter-long 50t round slings are used, each with two strands. The standard lifting sling U-shaped 0°-7° has a lifting factor of 2.

0. The allowable force at each crane lifting point is 50t*2=100t>68.25t. Step 6: Adjust the circumferential direction of the tower; Hang two plumb bobs from the 0° mark on the bottom of the tower, and hang a plumb bob from the 0° mark downward. Rotate the tower until the plumb bobs on both sides of the tower are the same size as the plumb bob at 0°. Step 7: Tower level measurement; Hang a plumb bob from the 0° position on all final assembly sealing welds along the length of the tower and measure the distance from the plumb bob to the left front corner main beam. The maximum error per linear meter at all positions should not exceed 1.3mm, and the maximum error of the total length of the cold box is 12.7mm; Adjust the instrument to a horizontal state, use X-ray to measure the 90° mark points of all closed welds on the tower body, and measure the distance from the plumb bob to the left front corner main beam. At all positions, the maximum error per linear meter should not exceed 1.3mm, and the maximum error of the total length of the cold box is 12.7mm.

2. The positioning method for a horizontal assembly tower of a large-scale air separation cold box according to claim 1 is characterized in that: In the step 2, the direction of the ribs points to the center of the tower, the middle rib is vertical, and the angles of the remaining ribs with the middle rib are 15° and 30°, and they are symmetrically distributed on both sides of the middle rib.

3. The positioning method for a horizontal assembly tower of a large-scale air separation cold box according to claim 1 is characterized in that: In the step 4, the tower support is installed after the horizontality of the cold box frame assembly is determined to be adjusted within the range of ±3mm, and the horizontality of the saddle-type support is within the range of ±3mm.

4. The positioning method for a horizontal assembly tower of a large-scale air separation cold box according to claim 1 is characterized in that: In the step 5, the tower is hoisted into place based on the base on which the tower is located after the air separation tower is installed in place, with no gap between the tower and the base, and the circumferential direction is based on the 0° mark direction.

5. The positioning method for a horizontal assembly tower of a large-scale air separation cold box according to claim 1 is characterized in that: In the step six, a jack support bracket is welded to the tower guard plate, and the tower angle is slowly and slightly adjusted by adjusting the jack to make the tower slowly suspend to adjust the tower.

6. The positioning method for a horizontal assembly tower of a large-scale air separation cold box according to claim 1, characterized in that: In step seven, the tower level is measured with the left front corner main beam as the reference, and the distance between the plumb bob and the main beam is measured.

7. The method for positioning a horizontal assembly tower of a large-scale air separation cold box according to claim 1, characterized in that: The tower bracket is a saddle-type seat. A plasma cutting machine is used to cut the stainless steel plate, and a blanking template is used for marking and cutting to ensure that the cutting size deviation meets the standard specifications. The edges of the components are polished and smooth, and impurities that affect welding are cleaned. The weld groove adopts a V-shaped groove, and the V-shaped groove angle is 55-65°.

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