Construction method of a pelletizing tower spray head layer in the form of a bailey frame

Abstract

This invention discloses a construction method for the nozzle layer of a Bailey bridge-type granulation tower. The method involves selecting a Bailey bridge as the support for the nozzle layer. The Bailey bridge is pre-assembled on the ground, and 22 integral Bailey bridge frames (adapted to the inner diameter of the granulation tower) are assembled using high-strength steel pins to connect basket-shaped Bailey panels. The middle 8 Bailey bridge frames are assembled into a single unit and hoisted to the slipform platform of the granulation tower, forming a unified structure. The slipform is then constructed to the support position, pre-embedded parts are installed, and steel brackets are welded at these locations. A manual hoist is used to place the Bailey bridge frame onto the steel brackets, and a limiting plate is welded for fixation. The Bailey bridge is then expanded, with the remaining 14 frames assembled. After assembly, a safety net is laid, and steel planks are fully laid on top of the Bailey bridge. The stiffening steel beams of the nozzle layer are assembled and installed, followed by rebar tying, formwork installation, and concrete construction. This invention utilizes Bailey bridges as the support for the nozzle layer construction of the granulation tower, shortening the construction preparation cycle, improving construction safety, and reducing the use of large hoisting equipment.

Description

Technical Field

[0001] This invention relates to the field of urea granulation tower nozzle layer construction technology in the new coal chemical industry, specifically, a Bailey gantry granulation tower nozzle layer construction method. Background Technology

[0002] In new coal chemical projects such as coal-to-oil and coal-to-gas, the urea granulation tower is a crucial link in the process of converting raw materials into products. It is an indispensable main structure for urea production, and the granulation tower nozzle layer is the supporting platform for converting urea solution into urea granules. In these new coal chemical projects, the granulation tower is over 110m high, and the nozzle layer construction is located at an elevation of 100m above the granulation tower. Selecting a reasonable, safe, and economical support structure is a prerequisite for nozzle layer construction. How to choose a support structure suitable for the construction site while ensuring construction safety and progress is a major challenge that urgently needs to be solved. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a novel support structure construction method for the construction of the nozzle layer of a granulation tower, so as to achieve the purpose of ensuring safe construction of the nozzle layer of the granulation tower and improving construction efficiency.

[0004] To solve the above technical problems, the present invention provides a method for constructing the nozzle layer of a Bailey bridge granulation tower, comprising the following steps:

[0005] Step 1: Select a Bailey bridge as the support for the nozzle layer;

[0006] Step 2: Calculate the support load of the nozzle layer. A single Bailey panel is used to connect every two Bailey frames, and every four Bailey frames are connected into a whole by horizontal connecting rods.

[0007] Step 3: Ground pre-assembly of Bailey bridge frames, using high-strength steel pins to assemble basket-shaped Bailey panels into 22 integral Bailey bridge frames adapted to the inner diameter of the granulation tower;

[0008] Step 4: Assemble the 8 Bailey bridge frames in the middle into a whole and hoist them onto the granulation tower slipform platform to form a whole with the slipform platform;

[0009] Step 5: Slipform construction to the support position, pre-embed the embedded parts, continue slipforming to the top of the tower, and test the strength of the test block under the same conditions to ensure it reaches the design strength; after the strength is reached, weld steel brackets at the embedded parts, use a manual hoist to place the Bailey bridge on the steel brackets and weld the limiting plate for fixation;

[0010] Step Six: Install the lifeline, expand the Bailey bridge, assemble the remaining 14 Bailey bridges, lay the safety net after assembly, and fully cover the top of the Bailey bridge with steel planks;

[0011] Step 7: Assembly and installation of the rigid steel beams for the nozzle layer, reinforcement binding, formwork installation, and concrete construction.

[0012] Furthermore, in step two, the main body of the Bailey bridge support platform is made of Q235-B profile, and the reinforcing members at the connection between the two sides and the tower wall are made of Q355-B profile.

[0013] Furthermore, in step four, there are two steel beam construction areas, each with two Bailey bridges; there are two Bailey bridges between the two steel beam construction areas; and there is one Bailey bridge on the outer side of each steel beam construction area.

[0014] Furthermore, in step six, one additional Bailey bridge is added between the two Bailey bridges in each steel beam construction area, for a total of two additional Bailey bridges; one additional Bailey bridge is added at each end of each steel beam construction area, for a total of four additional Bailey bridges.

[0015] Furthermore, in step six, four Bailey bridges are added between the corresponding ends of the two steel beam construction areas.

[0016] Furthermore, the two ends of the Bailey bridge outside the steel beam construction area are reinforced to the granulation tower wall by a single reinforcing rod, which is made of Q355-B single-limb 12# channel steel.

[0017] Furthermore, the two ends of the Bailey bridge in the steel beam construction area are reinforced to the granulation tower wall by double reinforcing rods, which are composed of Q355-B single-limb 12# channel steel.

[0018] Furthermore, the two ends of the Bailey bridge between the steel beam construction areas are reinforced to the granulation tower wall by a single central reinforcing rod, which is made of Q355-B single-limb 12# channel steel.

[0019] This invention provides a novel support mode for the construction of granulation tower nozzle layers: Bailey bridge support technology. Its features include convenient and flexible Bailey bridge selection, no need for customization, adaptability to the construction of granulation tower nozzle layers of various heights and diameters, high material turnover utilization, easy availability of construction materials, simple operation steps, and high safety, which helps to improve construction quality and efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic cross-sectional view of the Bailey bridge platform;

[0021] Figure 2 This is a schematic diagram of the Bailey bridge platform installation plan;

[0022] Figure 3 This is a schematic diagram of the load application in the Bailey bridge area corresponding to the steel beam in working condition 1;

[0023] Figure 4This is a schematic diagram of the load application on the steel beam in working condition 1 (the 22-ton steel beam is applied to the upper chord as a uniformly distributed load).

[0024] Figure 5 This is a schematic diagram of the load application on the support formwork for working condition 1;

[0025] Figure 6 This is a schematic diagram showing the application of loads to construction personnel and equipment under working condition 1;

[0026] Figure 7 This is a schematic diagram of the load application in the Bailey bridge area corresponding to the 26-meter span in working condition 2;

[0027] Figure 8 This is a schematic diagram showing the application of loads to the No. 8 channel steel and wooden plank of the distribution beam in working condition 2;

[0028] Figure 9 This is a schematic diagram of the load application for construction personnel and equipment in working condition 2;

[0029] Figure 10 This is a diagram of the Bailey bridge support displacement.

[0030] Figure 11 This is the overall stress and shear force diagram of the support frame;

[0031] Figure 12 This involves analysis of the buckling stability of the stent.

[0032] Figure 13 This is a 3D view of the FXYZ reaction force;

[0033] Figure 14 This is the FX reaction force diagram of the support;

[0034] Figure 15 This is the FY reaction diagram of the support;

[0035] Figure 16 This is the FZ reaction force diagram of the support;

[0036] Figure 17 This is the bending moment diagram of the support frame (Mx).

[0037] Figure 18 This is the bending moment diagram of the support frame (My).

[0038] Figure 19 This is the bending moment diagram of the support frame Mz;

[0039] Figure 20 This is a diagram of the Bailey bridge support displacement.

[0040] Figure 21 This is the overall stress and shear force diagram of the support frame;

[0041] Figure 22 This is a stress and shear force diagram of a Bailey bridge;

[0042] Figure 23 This is a stress and shear force diagram for channel steel.

[0043] Figure 24 This involves analysis of the buckling stability of the stent.

[0044] Figure 25 This is a 3D view of the FXYZ reaction force;

[0045] Figure 26 This is the FX reaction force diagram of the support;

[0046] Figure 27 This is the FY reaction diagram of the support;

[0047] Figure 28 This is the FZ reaction force diagram of the support;

[0048] Figure 29 This is the bending moment diagram of the support frame (Mx).

[0049] Figure 30 This is the bending moment diagram of the support frame (My).

[0050] Figure 31 This is the bending moment diagram of the support frame Mz.

[0051] In the diagram, 1-embedded pull ring, 2-steel wire strand, 3-steel bracket, 4-Bailey bridge, 5-steel bracket embedded part, 6-horizontal reinforcing bar, 7-granulation tower wall, 8-safety protection, 9-horizontal pergola, 10-single reinforcing bar, 11-double reinforcing bar, 12-steel beam construction area, 13-central single reinforcing bar, 14-horizontal connecting bar. Detailed Implementation

[0052] This embodiment provides a construction method for the nozzle layer of a Bailey bridge-type granulation tower, mainly including a novel support process for the construction of the nozzle layer of the granulation tower, as detailed below:

[0053] Construction preparation → Bailey bridge support selected → Bailey bridge support load calculation → Bailey bridge assembly into individual frames → Assembly of 8 frames into a whole → Slipforming to 23.50m → Bailey bridge connected to slipform platform → Slipforming completed → Steel bracket welding → Bailey bridge in place → Tensioning steel wire ropes → Assembling remaining Bailey bridges → Installing safety nets and steel scaffolding → Erection of operating frame → Welding and acceptance of main structure steel truss → Reinforcement binding → Formwork erection → Concrete pouring of sprinkler layer bottom slab → Frame erection → Shear wall reinforcement binding → Shear wall pouring → Top slab formwork → Top slab reinforcement → Top slab concrete → Bailey bridge dismantling.

[0054] The following example, using the urea relocation and upgrade project undertaken by the applicant, illustrates the novel support method for the spray layer construction of this granulation tower: the Bailey bridge support technology. The granulation tower in this project has an inner diameter of 26m, a tower height of 114.3m, and a spray layer elevation of 100.00m, employing a steel-concrete composite structure. The Bailey bridge support construction technology shortened the initial construction preparation work, reduced the construction period of the granulation tower, and provided valuable experience for the subsequent construction of the spray layer on the granulation tower.

[0055] Step 1: Select a Bailey bridge as the support for the nozzle layer;

[0056] In the current coal chemical industry, construction sites are compact and construction periods are tight. Using traditional scaffolding to construct the nozzle layer structure results in high scaffolding heights, inconsistent steel pipe quality, and compromised construction quality and safety. Using high-altitude steel platforms for formwork construction of the nozzle layer structure requires professional design and layout, as well as factory processing, which has a long processing cycle and is not universally applicable.

[0057] Based on the design load of the granulation tower nozzle layer and the diameter of the granulation tower, the upper load and lower support were calculated and selected. Since the existing support construction technology is insufficient to meet the tight construction period on the construction site, it is urgent to solve the construction technology problem by selecting a lightweight, high-strength, quick-to-install and dismantle, and easy-to-manufacture support. The Bailey bridge platform is selected as the construction support for the nozzle layer structure, which can meet the above requirements. The Bailey bridge is assembled with high-strength connecting rods and can adapt to various diameters and loads.

[0058] Step 2: Calculation of the support load for the nozzle layer;

[0059] According to calculations, the main body of the Bailey bridge support platform is made of Q235-B profile, and the connection between the two sides and the tower wall is reinforced with Q355-B profile. Each pair of Bailey bridges is connected by a single Bailey panel (0.9m*0.9m) at intervals. Every four Bailey bridges are connected into a whole by horizontal connecting rod 14 (Q235-B single leg [12# channel steel)) to ensure the integrity of the Bailey bridge platform.

[0060] The load calculation for the determined Bailey bridge construction supports is as follows:

[0061] 1. Characteristics of support materials

[0062] Components such as scissor braces, distribution beams, support frames, and Bailey bridges are all made of Q235B steel, while reinforcing members are made of Q355B steel. The mechanical properties of all materials are taken in accordance with the relevant provisions of the "Steel Structure Design Standard" (GB50017-2017).

[0063] Table 1 Support Members and Cross Sections

[0064]

[0065] Table 2 Design values ​​for steel strength (MPa)

[0066]

[0067] 1) Main verification contents

[0068] The verification mainly involves the deformation and stress of key load-bearing components, including distribution beams, support frames, and Bailey bridges. The main verification method is to establish a finite element model of the entire support system using MIDAS / civil software, and to analyze and calculate the strength and stiffness of each key structural part through numerical simulation to verify the overall stability of the support.

[0069] 2) Model Building

[0070] Based on the stress characteristics and mechanical principles of the relevant structures, beam elements are used to simulate the distribution beams and Bailey bridge structures in the finite element model, while truss elements (rod elements) are used to simulate the support frame. The Bailey bridge and distribution beams are connected in a general manner to simulate their stress conditions in actual engineering.

[0071] 2. Calculation process

[0072] According to Article 4.2 of the "Technical Specification for Safety of Formwork in Building Construction" (JGJ162-2008), when performing strength, stiffness and stability verification of the support structure, the partial factor for permanent load is taken as 1.3, the partial factor for variable load is taken as 1.5, and the structural safety factor is taken as 1.0.

[0073] 2.1 Permanent Loads

[0074] 1) Self-weight load

[0075] Working condition 1: Support self-weight G11

[0076] The self-weight of the Bailey bridge (Bailey bridge and support frame) is automatically calculated by MIDAS software based on the defined material properties and cross-section.

[0077] Working Condition 1: Self-weight of formwork and frame at the corresponding position of the steel beam (G12)

[0078] When a single-sided steel beam corresponds to three Bailey bridges, the steel beam value is: 22 tons = 220 kN. According to the corresponding three Bailey bridges, 220 kN / (24 meters * 3 bridges = 3.06 kN / m is applied to the upper chord of the Bailey bridge).

[0079] Template load value: 2.5KN / m2;

[0080] Full-span scaffolding value: 1KN / m2;

[0081] Table 3 Working Condition 1 (Single-sided steel beam corresponds to 3 Bailey bridges)

[0082]

[0083] 2) Working condition 2: Self-weight of support G21

[0084] The self-weight of the Bailey bridge (Bailey bridge and support frame) is automatically calculated by MIDAS software based on the defined material properties and cross-section.

[0085] Working condition 2: The self-weight of the distribution beams and planks laid on the Bailey bridge is G22.

[0086] The distribution beam is made of 8# channel steel at 1 meter intervals. Wooden planks are laid on the distribution beam within an area 26 meters long and 3.61 meters wide. The weight of the 8# channel steel is 27 pieces x 3.61 meters x 8.045 kg / m = 784.15 kg. The surface load is calculated as (784.15 * 10 / 1000) / 70.2 = 0.11 kN / m². The load on the wooden planks is calculated as 0.89 kN / m². The total load of the distribution beam (channel steel and wooden planks) is 1 kN / m².

[0087] 2.2 Variable Loads

[0088] 1) Working Condition 1: Load of Construction Personnel and Equipment Q1

[0089] According to relevant specifications and construction plans, the load on construction personnel, materials, and equipment during construction is 2.5 kN / m².

[0090] Table 4 Working Condition 1 (Single-sided steel beam corresponds to 3 Bailey bridges)

[0091]

[0092] 2) Working Condition 2: Load of Construction Personnel and Equipment Q21

[0093] According to relevant specifications and construction plans, the load on construction personnel, materials, and equipment during construction is 2.5 kN / m².

[0094] Table 5 Operating Condition 2 (Maximum Span of Granulation Tower)

[0095]

[0096] 2.3 Load Combinations

[0097] Taking into account the specifications and site conditions, the combination of permanent and variable loads used in the verification is shown in the table below.

[0098] Table 6 Load Combinations for Support Design Calculation

[0099]

[0100] 2.4 Schematic diagram of load application

[0101] like Figures 3 to 9 As shown, Figure 3 This is a schematic diagram showing the load application to the Bailey bridge area corresponding to the steel beam in load case 1. Figure 4 This is a schematic diagram of the load application on the steel beam in working condition 1 (the 22-ton steel beam is applied to the upper chord as a uniformly distributed load). Figure 5 This is a schematic diagram illustrating the application of loads to the formwork support in condition 1. Figure 6 A schematic diagram showing the loads applied to construction personnel and equipment in working condition 1. Figure 7 This is a schematic diagram showing the load application in the Bailey bridge area corresponding to a 26-meter span in working condition 2. Figure 8 A schematic diagram showing the application of loads to beam #8 and the wooden plank for load case 2. Figure 9 This is a schematic diagram showing the application of loads to construction personnel and equipment in working condition 2.

[0102] 2.5 Calculation results of support structure under working condition 1

[0103] Based on the engineering data, load case 1 is selected as the load calculation object. Under the same design parameters, if the stress and strain values ​​of the support meet the requirements, then the support can meet the requirements. Therefore, the MIDAS modeling takes the overall Bailey bridge support as the target and analyzes its stress and deformation.

[0104] 2.5.1 Deformation amount under working condition 1

[0105] The overall deformation is shown in the figure. To more clearly show the deformation trend of the support, the deformation of the structure in the figure has been magnified (200 times).

[0106] Figure 10 The diagram shows the displacement of the Bailey bridge support. The location with the largest deformation of the Bailey bridge support is in the middle of the span, and its maximum value is 20mm < 24000 / 1000mm = 24mm, which meets the deformation requirements.

[0107] 2.5.2 Working Condition 1 Strength

[0108] Figure 11 The diagram shows the overall stress and shear force of the support structure. As can be seen from the diagram, the maximum combined stress of the Bailey bridge structure is 298MPa < 305MPa, and the maximum shear stress is 41MPa < 175MPa; which meets the safety requirements.

[0109] 2.5.3 Buckling stability under condition 1

[0110] The critical load factor (the ratio of the maximum load that may cause buckling stability problems to the specified standard load) of the entire support system was obtained by performing eigenvalue analysis on the members using MIDAS software. The results are as follows: Figure 12 As shown.

[0111] As can be seen from the figure, the critical load factors of the support in the five modes are as follows:

[0112] Table 7 Critical Load Factors

[0113]

[0114] 2.5.4 Calculation results for other structures under working condition 1

[0115] 1) Foundation reaction force in working condition 1

[0116] A schematic diagram of the reaction force at the bottom of the Bailey bridge is shown below. Figures 13-19 As shown, the reaction force at the bottom of the Bailey bridge indicates that a large horizontal tensile force and vertical reaction force are generated when the bottom of the Bailey bridge is fixed. Since the Bailey bridge rests on steel brackets, the steel brackets must be able to withstand the vertical force (shearing force of the weld) and pull-out force (pulling force of the weld) of the Bailey bridge. Similarly, the brackets are welded to embedded parts, and the embedded parts must resist the pull-out force and shear force. FX horizontal tensile force = 340KN / frame, a single Bailey bridge consists of three frames; FZ vertical shear force = 139KN / frame, a single Bailey bridge consists of three frames.

[0117] 2.6 Calculation results of the support structure under working condition 2

[0118] Based on the engineering data, load case 1 is selected as the load calculation object. Under the same design parameters, if the stress and strain values ​​of the support meet the requirements, then the support can meet the requirements. Therefore, the MIDAS modeling takes the overall Bailey bridge support as the target and analyzes its stress and deformation.

[0119] 2.6.1 Deformation amount under working condition 2

[0120] The overall deformation is shown in the figure. To more clearly show the deformation trend of the support, the deformation of the structure in the figure has been magnified (200 times).

[0121] Figure 20 The diagram shows the displacement of the Bailey bridge support. The location with the largest deformation of the Bailey bridge support is in the middle of the span, and its maximum value is 23mm < 26000 / 1000mm = 26mm, which meets the deformation requirements.

[0122] 2.6.2 Working Condition 2 Strength

[0123] Figure 21 The overall stress and shear force diagram of the support structure is shown. Figure 22 Stress and shear force diagrams for the Bailey bridge. Figure 23 The diagram shows the stress and shear force of the channel steel. As can be seen from the diagram, the maximum combined stress of the Bailey bridge structure is 256 MPa < 305 MPa, and the maximum shear stress is 69.5 MPa < 175 MPa; the maximum combined stress of the 8 channel steels is 57 MPa < 205 MPa, and the maximum shear stress is 12.2 MPa < 120 MPa; both meet safety requirements.

[0124] 2.6.3 Buckling stability under working condition 2

[0125] The critical load factor (the ratio of the maximum load that may cause buckling stability problems to the specified standard load) of the entire support system was obtained by performing eigenvalue analysis on the members using MIDAS software. The results are as follows: Figure 24 As shown in the figure, the critical load factors of the support in the five modes are as follows:

[0126] Table 8 Critical Load Factor Table

[0127]

[0128] 2.6.4 Calculation results for other structures under working condition 2

[0129] 1) Foundation reaction force in working condition 2

[0130] A schematic diagram of the reaction force at the bottom of the Bailey bridge is shown below. Figures 25-31 As shown. The reaction force at the bottom of the Bailey bridge indicates that a large horizontal tensile force and vertical reaction force are generated when the bottom of the Bailey bridge is fixed. Since the Bailey bridge rests on steel brackets, the steel brackets must be able to withstand the vertical force (shearing force of the weld) and pull-out force (pulling force of the weld) of the Bailey bridge. Similarly, the brackets are welded to embedded parts, and the embedded parts must resist the pull-out force and shear force. FX horizontal tensile force = 189KN / frame, FZ vertical shear force = 127KN / frame. A single Bailey bridge consists of three frames.

[0131] Step 3: Pre-assemble the Bailey bridge on the ground. Use high-strength steel pins to assemble the basket-shaped Bailey panels into 22 integral Bailey bridge frames suitable for the inner diameter of the granulation tower. Place them near the construction area of ​​the granulation tower for easy hoisting and transportation.

[0132] Step 4: Assemble the 8 Bailey bridge frames into a single unit. Use a 200t crane for hoisting and hoisting the frames onto the slipform platform of the granulation tower, where they will form a unified structure. In this embodiment, there are two steel beam construction areas 12, each with two Bailey bridge frames; two Bailey bridge frames are located between the two steel beam construction areas 12; and one Bailey bridge frame is located on the outer side of each steel beam construction area 12.

[0133] Step 5: Slipform construction to the support position, pre-embed the pre-embedded parts, continue slipform to the top of the tower, and test the strength of the test block under the same conditions to ensure it reaches the design strength; after the strength is reached, ride the basket to the pre-embedded parts to weld the steel bracket 3, and the weld seam meets the requirements after penetrant testing. Use a manual hoist to place the Bailey frame 4 on the steel bracket 3 and weld the limiting plate to fix it. The granulation tower wall 7 is pre-embedded with a pre-embedded pull ring 1, and the Bailey frame 4 and the pre-embedded pull ring 1 are connected by steel wire strand 2.

[0134] Step Six: Install the lifeline, expand the Bailey bridge, assemble the remaining 14 Bailey bridges according to the calculation requirements, lay the safety net after assembly, and fully cover the top of the Bailey bridge with steel planks.

[0135] One additional Bailey bridge is added between each of the two existing Bailey bridges in each steel beam construction area 12, for a total of two additional Bailey bridges; one additional Bailey bridge is added at each end of each steel beam construction area 12, for a total of four additional Bailey bridges. Four additional Bailey bridges are added between the corresponding ends of two steel beam construction areas 12.

[0136] The Bailey bridge support platform is reinforced to the granulation tower wall by horizontal reinforcing rods 6. Specifically, the two ends of the Bailey bridge outside the steel beam construction area are reinforced to the granulation tower wall by single reinforcing rods 10, which are made of Q355-B single-limb 12# channel steel. The two ends of the Bailey bridge within the steel beam construction area are reinforced to the granulation tower wall by double reinforcing rods 11, which are composed of Q355-B single-limb 12# channel steel. The two ends of the Bailey bridge between the steel beam construction areas are reinforced to the granulation tower wall by a central single reinforcing rod 13, which is also made of Q355-B single-limb 12# channel steel.

[0137] Step 7: Assembly and installation of the rigid steel beams for the nozzle layer, reinforcement binding, formwork installation, and concrete construction.

Claims

1. A method of construction of a prill tower shower layer by use of a Bailey frame, characterized in that, Includes the following steps: Step 1: Select a Bailey bridge as the support for the nozzle layer; Step 2: Calculate the support load of the nozzle layer. A single Bailey panel is used to connect every two Bailey frames, and every four Bailey frames are connected into a whole by horizontal connecting rods. Step 3: Ground pre-assembly of Bailey bridge frames, using high-strength steel pins to assemble basket-shaped Bailey panels into 22 integral Bailey bridge frames adapted to the inner diameter of the granulation tower; Step 4: Assemble the 8 Bailey bridge frames in the middle into a whole and hoist them to the granulation tower slipform platform to form a whole with the slipform platform; there are two steel beam construction areas, each with two Bailey bridge frames; there are two Bailey bridge frames between the two steel beam construction areas; there is one Bailey bridge frame on the outside of each steel beam construction area; Step 5: Slipform construction to the support position, pre-embed the embedded parts, continue slipforming to the top of the tower, and test the strength of the test block under the same conditions to ensure it reaches the design strength; after the strength is reached, weld steel brackets at the embedded parts, use a manual hoist to place the Bailey bridge on the steel brackets and weld the limiting plate for fixation; Step Six: Install the lifeline and expand the Bailey bridge. Add one Bailey bridge between each pair of steel beam construction areas, for a total of two additional Bailey bridges; add one Bailey bridge at each end of each steel beam construction area, for a total of four additional Bailey bridges; add four Bailey bridges between corresponding ends of two steel beam construction areas; assemble the remaining 14 Bailey bridges, lay the safety netting after assembly, and fully cover the top of the Bailey bridges with steel planks. Step 7: Assembly and installation of the rigid steel beams for the nozzle layer, reinforcement binding, formwork installation, and concrete construction.

2. The method of claim 1, wherein: In step two, the main body of the Bailey bridge support platform is made of Q235-B profile, and the reinforcing members at the connection between the two sides and the tower wall are made of Q355-B profile.

3. The method for constructing the spray nozzle layer of a Bailey frame granulation tower according to claim 1 or 2, characterized in that: The two ends of the Bailey bridge outside the steel beam construction area are reinforced to the granulation tower wall by a single reinforcing rod, which is made of Q355-B single-limb 12# channel steel.

4. The method for constructing the spray nozzle layer of the Bailey frame granulation tower according to claim 3, characterized in that: The two ends of the Bailey bridge in the steel beam construction area are reinforced to the granulation tower wall by double reinforcing rods, which are made of Q355-B single-limb 12# channel steel.

5. The construction method for the spray head layer of the Bailey frame granulation tower according to claim 4, characterized in that: The two ends of the Bailey bridge between the steel beam construction areas are reinforced to the granulation tower wall by a single central reinforcing rod, which is made of Q355-B single-limb 12# channel steel.

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