Multi-point uniform distribution translation type hoisting method for light furnace top

Abstract

The invention discloses a light furnace top multipoint uniform distribution translation type hoisting method which comprises the following steps: firstly, determining hoisting point positions, prefabricating and mounting lifting lugs, selecting a central line of a light furnace top as a symmetry axis of the hoisting points, arranging two hoisting points on a spandrel girder where the central line of the light furnace top is located, and symmetrically and uniformly distributing the hoisting points on two sides of the symmetry axis on the spandrel girder of the light furnace top. A crane stands to the rear side of the boiler, a rigging is hung to lift the light furnace top to the boiler side from the prefabricated platform, the light furnace top is rotated to adjust the mounting direction, the light furnace top is stably lifted to the lifting height, a suspension arm is rotated to horizontally move the light furnace top to the mounting position, and finally, the crane falls a hook, and the light furnace top is stably located on the boiler body steel structure frame. A plurality of uniformly distributed lifting lugs are prefabricated and mounted on the light furnace top, so that the risks that the light furnace top is large in area, uneven in stress and deformed and damaged in the lifting process are avoided; meanwhile, the risk that the light furnace top is crossed and collided with a crane suspension arm lever and a furnace top steam pocket is avoided through translation type installation.

Description

Technical Field

[0001] The invention relates to the field of equipment hoisting of coal chemical projects, in particular to a method for hoisting a light furnace top of a boiler. Background Art

[0002] The light furnace roof is a protective component of the boiler body and is installed on the top of the boiler body. As the last large part of the boiler body, the light furnace roof not only has a high hoisting height, but also covers an area of ​​more than 600 square meters and weighs about 50 tons. There are two main traditional hoisting methods: the first method is overall hoisting: a shoulder pole / balance beam or support steel ring is required to ensure that the light furnace roof does not deform during the hoisting process; the second method is block hoisting: the light furnace roof is assembled in blocks, and hoisted and welded one by one. Both methods have complicated construction procedures, many high-altitude operations, and many safety hazards during the construction process. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a multi-point uniformly distributed translational lifting method for a light furnace roof, optimize the construction process, and achieve the purpose of avoiding deformation of the light furnace roof and reducing safety hazards.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A multi-point uniformly distributed translational lifting method for a light furnace roof, comprising:

[0006] Step 1: determine the location of the lifting point and prefabricate and install the lifting lugs;

[0007] Step 2: Select the lifting machinery and wire rope according to the lifting height and the weight of the light furnace top;

[0008] Step 3: The crane stands at the rear of the boiler, hangs the rigging and lifts the light furnace roof from the prefabricated platform to the furnace side;

[0009] Step 4: Turn the light furnace top to adjust the installation position;

[0010] Step 5: Steadily lift the light furnace top to the hoisting height;

[0011] Step 6: Rotate the crane arm to translate the light furnace roof to the installation position;

[0012] Step seven: The crane drops the hook and places the lightweight furnace roof steadily on the steel structure frame of the boiler body.

[0013] As a preferred implementation, in step one, the hanging points are selected with the center line of the light furnace roof as the symmetry axis, two hanging points are set on the load-bearing beam where the center line of the light furnace roof is located, and the hanging points on both sides of the symmetry axis are symmetrically and evenly distributed on the load-bearing beam of the light furnace roof.

[0014] As a preferred embodiment, a hanging point is provided at each of the four corners of the lightweight furnace roof.

[0015] As a preferred embodiment, in step one, the lifting ear is welded and fixed to the load-bearing beam, and the lifting ear includes a base plate, a hanging plate and a stiffening plate, the hanging plate is vertically fixed to the middle of the base plate and a lifting hole is opened in the middle of the hanging plate, and the stiffening plate is connected to the sides of the base plate and the hanging plate.

[0016] As a preferred implementation, in step three, the lengths of the steel wire ropes at the symmetrical lifting positions are consistent.

[0017] As a preferred embodiment, tail ropes are provided at the four corners of the light furnace roof, and the installation position of the light furnace roof is adjusted by pulling the tail ropes.

[0018] The present invention prefabricates and installs a plurality of evenly distributed lifting ears on the light furnace roof and reasonably selects the length of the wire rope and the lifting machinery, thereby successfully avoiding the risks of large light furnace roof area, uneven force, and deformation and damage during lifting. At the same time, the translational installation avoids the risk of cross-collision between the light furnace roof and the crane boom and the furnace roof steam drum. The overall lifting reduces the construction workers' high-altitude and edge operations, reducing safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings herein are used to provide further explanation of the present invention and constitute a part of this application. The illustrative embodiments of the present invention and their description are used to explain the present invention and do not constitute improper limitations on the present invention.

[0020] Figure 1 This is a diagram showing the arrangement of the light furnace top suspension points of the present invention;

[0021] Figure 2 It is a schematic diagram of the lifting lug of the present invention;

[0022] Figure 3 A schematic diagram of the steel wire rope of the present invention is selected;

[0023] Figure 4 This is a schematic diagram of the crane station location of the present invention;

[0024] Figure 5 It is a schematic diagram of the lifting and installation of the light furnace roof of the present invention.

[0025] 1-light furnace roof, 2-hanging point, 3-crane, 4-rigging, 5-boiler, 6-load-bearing beam, 7-bottom plate, 8-hanging plate, 9-strength plate, 10-hanging hole. DETAILED DESCRIPTION

[0026] This implementation involves the hoisting of two 200t / h circulating fluidized bed boiler light furnace roofs. The light furnace roof of a single boiler is 26.82m long, 23.4m wide, 627.588㎡ in area, 50.63t in mass, and 45m in lifting height. There are many cross-operations on site, small hoisting space, large area of ​​light furnace roof, and heavy mass, which bring many inconveniences to the hoisting operation.

[0027] Based on this, a typical embodiment of the present invention provides a multi-point uniformly distributed translational lifting method for a light furnace roof, comprising:

[0028] Step 1: Determine the position of lifting point 1 and prefabricate and install the lifting lugs.

[0029] The hanging point 2 is selected with the center line of the light furnace roof 1 as the symmetry axis, two hanging points 2 are set on the load-bearing beam where the center line of the light furnace roof 1 is located, and the hanging points 2 on both sides of the symmetry axis are symmetrically and evenly distributed on the load-bearing beam of the light furnace roof 1.

[0030] Since the overall area of ​​the light furnace roof 1 is relatively large, a hanging point 2 is set at each of the four corners to prevent the four corners from collapsing and deforming during the hoisting process. Two hanging points are set on the center line of the light furnace roof 1 to prevent the middle crossbeam from brittle fracture due to the tension on both sides of the center line. The hanging points are symmetrically distributed and welded on the light furnace roof load-bearing beam to ensure that during the entire light furnace roof hoisting process, the horizontal force components of each hanging ear are in opposite directions and the vertical force components are in the same direction.

[0031] In a relatively specific embodiment, Figure 1 As shown, a total of 22 lifting lugs are arranged on the light furnace roof 1. The load-bearing beams of the light furnace roof 1 include transverse load-bearing beams and longitudinal load-bearing beams. The middle longitudinal load-bearing beam is used as the symmetry axis, and two lifting points 2 are arranged on it. A total of 4 lifting lugs are arranged at the four corners. On both sides of the symmetry axis, lifting lugs are arranged at the intersections of the transverse load-bearing beams and the longitudinal load-bearing beams, and 8 lifting points are arranged on each lifting lug on any side (excluding the lifting points at the four corners). The 8 lifting points are arranged in 4 rows and 2 columns, and the spacing between the lifting points in each row is equal, and the spacing between the lifting points in each column is equal.

[0032] like Figure 2 As shown, the lifting lug is welded and fixed to the load-bearing beam 6, and the lifting lug includes a bottom plate 7, a hanging plate 8 and a stiffening plate 9. The hanging plate 8 is vertically fixed to the middle of the bottom plate 1 and a hanging hole 10 is opened in the middle of the hanging plate 8. The stiffening plate 9 is connected to the sides of the bottom plate 7 and the hanging plate 8. The bottom plate 7 is firmly welded to the light furnace roof 1 to reduce the local stress of the light furnace roof beam. The hanging hole 10 on the hanging plate 8 connects the rigging 4 to the light furnace roof 1. The stiffening plate 9 is used to strengthen the stability of the hanging plate 8 so that the hanging plate 8 will not swing left and right during the lifting process.

[0033] The specifications of the lifting lugs are 200mm*150mm*12, with a total of 22 symmetrically distributed. The lifting lug material is Q235B, and the tensile strength is 375MPa.

[0034]

[0035] (1) Calculation of allowable load of lifting lugs

[0036] In the formula: P--allowable load of lifting lug (N), D-lifting weight (N), C-uneven force coefficient, C=1.5-2n-number of lifting lugs subjected to force at the same time, n=22.

[0037] Substituting the data into the equation, we get: P = 41627.73N

[0038] (2) Strength check of lifting lugs

[0039]

[0040] 1) Normal stress

[0041] 2) Shear stress

[0042]

[0043] Where: Fmin--the minimum cross-sectional area perpendicular to the direction of P force (mm 2 ), Amin--the minimum cross-sectional area parallel to the direction of P force (mm 2 ) The safety factor K is generally taken as 2.5~3.0, σs--the yield limit of steel is 235MPa.

[0044] [σ]- allowable normal stress of material, [σ] = 235 / 3Mpa = 78.3Mpa,

[0045] [τ]--the allowable shear stress of the material, [τ] = 0.6 [σ] = 75Mpa,

[0046] Substituting the data, we get: normal stress σ=23.13MPa<[σ]=78.3MPa, shear stress τ=28.9MPa<[τ]=75Mpa

[0047] Therefore, the lug strength meets the requirements.

[0048] Weld strength check of lifting lugs:

[0049]

[0050] Where: D-vertical tension acting on the lifting lug (N), -Weld width, mm;

[0051] ∑1-total length of weld, mm;

[0052] [τ h ]-Allowable shear stress of weld, [τ h ]=67.5MPa

[0053] Substituting the data, we get: τh=8.565<[τ h ]=67.5MPa.

[0054] Therefore, the weld strength meets the requirements.

[0055] (3) Nondestructive testing of lifting lugs

[0056] After the lifting lugs are prefabricated, non-destructive testing is carried out on site, and penetration testing is carried out in accordance with NB / T47013-2015, with a qualified level of I.

[0057] Step 2: Select the lifting machinery and wire rope according to the lifting height and weight of the light furnace roof 1.

[0058] like Figure 3 As shown, the vertical distance h from the hanging point 2 to the hook is the same, and the distances l1, l2, and l3 between the hanging point 2 and the center of the light furnace roof 1 can be measured on site, and the corresponding wire rope lengths L1, L2, and L3 can be calculated according to the Pythagorean theorem. The lengths of the wire ropes 3 at each symmetrical position are the same, and the vertical distance h from each lifting lug to the hook is the same. According to the vector triangle of the force, the horizontal force components of each lifting lug are equal in magnitude and opposite in direction, and the vertical force components are the same in magnitude and direction, so the wire rope of the corresponding diameter is selected according to the deadweight of the light furnace roof 1.

[0059] The light furnace roof is 26.82m long, 23.4m wide and weighs 50.63t. It is planned to be hoisted by a 400t crawler crane with multi-point uniform distribution. The main arm working condition is 84m, the operating radius is 30m, and the lifting capacity is 97t. Force calculation when using a 400t crawler crane for hoisting:

[0060] According to: P = (F + q) × K

[0061] P: lifting load;

[0062] F: furnace top weight;

[0063] q: the sum of the weight of the sling and the rigging;

[0064] K: dynamic load coefficient, take 1.1;

[0065] So P = (50.63 + 6) × 1.1 = 62.3t;

[0066] Crane load rate: η=62.3 / 97×100%=64.2%<80%, meeting construction safety requirements.

[0067] Calculation of main hoist wire rope:

[0068] Calculate the length L of each wire rope according to the distance l from each hanging point to the center of gravity and the distance h from the hook to the center of gravity. Each wire rope is symmetrically distributed, with equal and opposite forces in the horizontal direction, and the resultant force is 0. The vertical force is consistent at 2.84t. According to the vector triangle of the force, it is deduced that the maximum horizontal force of a single wire rope is 2.84t and the maximum tension is 4t. According to the calculation results, 22 34*7+FC steel core wire ropes with a diameter of 28mm are selected, including 4 25.8m long, 4 22.2m long, 4 20.8m long, 4 20.4m long, 2 19.4m long, and 4 19m long. According to the mechanical properties of Table 9 of "Important Purpose Wire Rope" GB 8918-2006, it can be seen that the minimum breaking tension of a single wire rope is 441KN, and the force calculation is:

[0069] The safety factor of the wire rope is n1 = 441 / 62.3 = 7.08 > 6

[0070] The safety ratio is in line with the requirements of SY-76279-2016 "Safety Regulations for Lifting of Large Equipment", which is greater than 6 times.

[0071] Step 3: The crane 3 is positioned at the rear side of the boiler 5, and the rigging 4 is hung to lift the light furnace roof 1 from the prefabricated platform to the furnace side.

[0072] One end of the rigging 4 is connected to the lifting lug, and the other end is hung on the hook of the crane 3. The tail rope is tied to the four corners of the light furnace roof 1, and the light furnace roof is lifted steadily to the furnace side after checking that it is correct.

[0073] Step 4: Turn the light furnace top to adjust the installation position.

[0074] In this step, the installation position of the light furnace roof 1 is adjusted by pulling the tail rope.

[0075] Step 5: Steadily lift the light furnace top to the lifting height.

[0076] Step six, rotate the boom to move the lightweight furnace roof horizontally to the installation position.

[0077] like Figure 4 and Figure 5 As shown, the side facing the boiler with its back to the main plant is the front of the furnace, and the other side is the back of the furnace. The crane 3 is located behind the furnace, and the light furnace roof 1 is on the side of the furnace. This will lift the light furnace roof 1 from the side of the boiler body to the installation height. The crane 3 rotates the boom to move the light furnace roof 1 horizontally into place, cleverly avoiding the safety risk of the light furnace roof steel column colliding with the steam drum when the light furnace roof is hoisted from the front / back of the furnace.

[0078] Step 7: The crane drops the hook, places the light furnace roof stably on the boiler body steel structure frame, and welds the light furnace roof column 1 to the boiler body steel structure frame.

[0079] The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various deformations and changes. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-point uniformly distributed translational lifting method for a light furnace roof, characterized in that: include: Step 1: determine the location of the lifting point and prefabricate and install the lifting lugs; Step 2: Select the lifting machinery and wire rope according to the lifting height and the weight of the light furnace top; Step 3: The crane stands at the rear of the boiler, hangs the rigging and lifts the light furnace roof from the prefabricated platform to the furnace side; Step 4: Turn the light furnace top to adjust the installation position; Step 5: Steadily lift the light furnace top to the hoisting height; Step 6: Rotate the crane arm to translate the light furnace roof to the installation position; Step seven: The crane drops the hook and places the lightweight furnace roof steadily on the steel structure frame of the boiler body.

2. The method for lifting a light furnace roof at multiple points evenly distributed and translated according to claim 1 is characterized in that: In step one, the hanging points are selected with the center line of the light furnace roof as the symmetry axis, two hanging points are set on the load-bearing beam where the center line of the light furnace roof is located, and the hanging points on both sides of the symmetry axis are symmetrically and evenly distributed on the load-bearing beam of the light furnace roof.

3. The method for lifting a light furnace roof at multiple points evenly distributed and translated according to claim 2 is characterized in that: There is a hanging point at each of the four corners of the light furnace top.

4. The multi-point uniformly distributed translational lifting method for a light furnace roof according to claim 1 or 3, characterized in that: In step one, the lifting ear is welded and fixed to the load-bearing beam. The lifting ear includes a base plate, a hanging plate and a stiffening plate. The hanging plate is vertically fixed to the middle of the base plate and a lifting hole is opened in the middle of the hanging plate. The stiffening plate is connected to the sides of the base plate and the hanging plate.

5. The method for evenly distributed translational lifting of a light furnace roof at multiple points according to claim 4 is characterized in that: In step three, the lengths of the wire ropes at the symmetrical lifting locations are consistent.

6. The method for lifting a light furnace roof at multiple points evenly distributed and translating according to claim 5 is characterized in that: There are tail ropes at the four corners of the light furnace roof. Pull the tail ropes to adjust the installation position of the light furnace roof.

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