Method for installing a box girder of a bgl gasifier installation

Abstract

The application discloses a BGL gasification furnace device box girder installation construction method and relates to the technical field of gasification furnace device installation. The box girder is segmented and prefabricated into two box girder sections and pre-assembled. When segmented and prefabricated, an assembling and closing position is planned in the middle of the longitudinal beam of the box girder, and the first box girder section and the second box girder section are respectively prefabricated according to the assembling and closing position. The two box girder sections are transported to the construction site, lifted to the first concrete frame beam at the set elevation from the bottom of the concrete frame and respectively placed in the reserved positions on the front and rear sides of the first concrete frame beam, and the gasification furnace is lifted to the position above the installation elevation. The two box girder sections are lifted away from the first concrete frame beam, the first box girder section and the second box girder section are horizontally moved to be close to the gasification furnace, the two box girder sections are closed from the closing position, and finally the gasification furnace is positioned. The application can reduce the high-altitude lifting risk and improve the construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of gasifier installation technology, and more specifically, to a method for installing box-type beams in a BGL gasifier. Background Technology

[0002] The BGL gasifier, as the core equipment of the gasification unit, has advantages such as low oxygen consumption, high conversion rate, and low emissions. The box girder of the gasifier is installed inside the concrete frame beam. The traditional manufacturing and installation process involves assembling individual components at a height, which greatly increases the working time for hot work at heights and requires the addition of working platforms. This increases the probability of fire, explosion, and falling objects from heights, posing significant safety risks.

[0003] In conclusion, developing a pre-assembly and installation method for box-type beams of BGL gasifier units remains a critical issue that urgently needs to be addressed in the field of gasifier unit installation technology. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for installing box beams of BGL gasifier devices, which reduces the amount of high-altitude work and improves construction efficiency.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] A method for installing box-type beams in a BGL gasifier unit includes the following steps:

[0007] The box girder includes two parallel horizontal beams, two parallel longitudinal beams in the middle of the horizontal beams, and an inclined beam between the inner side of the longitudinal beams and the horizontal beams; the box girder is installed in a concrete frame after being lifted.

[0008] Step 1: The box girder is prefabricated into two box girder segments and pre-assembled. During segment prefabrication, the splicing and joining position is planned in the middle of the longitudinal beam of the box girder, and the first box girder segment and the second box girder segment are prefabricated according to the splicing and joining position.

[0009] Step two: Transport the two box girder segments to the construction site. From the bottom of the concrete frame, lift the first and second box girder segments onto the first concrete frame beam at the set elevation. Place the first and second box girder segments in the reserved positions on the front and rear sides of the first concrete frame beam, respectively. Leave space between the first and second box girder segments for lifting and installing the gasifier. Lift the gasifier to a position above the installation elevation.

[0010] Step 3: Lift the first box girder segment and the second box girder segment away from the first concrete frame beam; set the first manual hoist on the side of the two concrete frame columns near the middle of the first concrete frame beam, and connect the two first manual hoists on each frame column to the lifting lugs at the ends of the crossbeams of the two box girder segments. Move the first box girder segment and the second box girder segment horizontally closer to the gasifier, and join the two box girder segments together from the splicing and joining position.

[0011] Furthermore, in step two, after the two box girder segments are unloaded, they are hoisted onto a steel trailer using a crawler crane, and the steel trailer is horizontally pulled to transport the two box girder segments to the ground at the bottom of the concrete frame.

[0012] Furthermore, in step two, during the transportation of the box girder, the foundation of the walkway for horizontal traction is prepared in advance, the steel trailer is placed on the steel plate, and grease is used to lubricate the steel trailer and the steel plate.

[0013] Furthermore, in step three, a second manual hoist and a third manual hoist are installed on the second concrete frame beam, which is higher than the height of the first concrete frame beam. After the two box girder segments are lifted to the reserved positions on the first concrete frame beam, the second manual hoist is connected to the lifting lug on the first box girder segment, and the third manual hoist is connected to the lifting lug on the second box girder segment, so that the first box girder segment and the second box girder segment are lifted away from the first concrete frame beam.

[0014] Furthermore, in step three, the lifting lugs on the first box girder connected to the second manual hoist are set at the connection points of the two crossbeams and longitudinal beams of the first box girder and in the middle of the two longitudinal beams.

[0015] Furthermore, in step three, the lifting lugs on the second box girder connected to the third manual hoist are set at the connection points of the two crossbeams and longitudinal beams of the second box girder and in the middle of the two longitudinal beams.

[0016] This invention, by pre-assembling and prefabricating box girder beams in a processing plant, can solve problems such as large gaps in component connections, misalignment of connection surfaces, deviation in connection positions, and welding deformation caused by errors. This effectively ensures smooth on-site hoisting and welding installation, reduces the amount of high-altitude welding and hoisting work, shortens the installation period of a single gasifier, improves the turnover rate and utilization rate of large hoisting machinery for the main gasifier, saves the cost of large and medium-sized hoisting machinery, reduces the amount of scaffolding erection, lowers the difficulty and risk of safety control, saves resource consumption, and facilitates project progress control.

[0017] After the gasifier is hoisted to a position above the design elevation, the box girder is horizontally pulled together to the design installation position using a hoist. After positioning, the welding and assembly of the nodes begins, and the gasifier is placed in place at the same time, reducing the risk of high-altitude hoisting. Attached Figure Description

[0018] The accompanying drawings, which are provided to further illustrate the invention and form part of this application, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention.

[0019] Figure 1 This is a schematic diagram showing the arrangement of the box girder at the reserved position of the first concrete frame beam.

[0020] Figure 2 This is a schematic diagram showing the lifting point setup when the box girder is ready to be closed.

[0021] In the diagram, 1-first box girder segment, 2-second box girder segment, 3-first concrete frame beam, 4-concrete frame column, 5-lifting lug, 6-crossbeam, 7-longitudinal beam, 8-slanting beam. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the present invention will be further described clearly and completely below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0023] In a typical embodiment of the present invention, the box girder of the BGL gasifier device includes two parallel crossbeams 6, two parallel longitudinal beams 7 in the middle of the crossbeams 6, and an inclined beam 8 between the inner side of the longitudinal beams 7 and the crossbeams 6; the box girder is installed in a concrete frame after being lifted.

[0024] The above-mentioned BGL gasifier unit box girder installation construction method mainly includes the following steps:

[0025] Step 1: The box girder is prefabricated into two box girder segments and pre-assembled. During segment prefabrication, the splicing and joining position is planned in the middle of the longitudinal beam of the box girder, and the first box girder segment 1 and the second box girder segment 2 are prefabricated according to the splicing and joining position.

[0026] Step two: Transport the two box girder segments to the construction site. From the bottom of the concrete frame, lift the first box girder segment 1 and the second box girder segment 2 onto the first concrete frame beam 3 at the set elevation. Place the first box girder segment 1 and the second box girder segment 2 in the reserved positions on the front and rear sides of the first concrete frame beam 3, leaving space between the first box girder segment 1 and the second box girder segment 2 for lifting and installing the gasifier. Lift the gasifier to a position above the installation elevation.

[0027] Step 3: Lift the first box girder segment 1 and the second box girder segment 2 away from the first concrete frame beam 3; set the first manual hoist on the side of the two concrete frame columns 4 near the middle of the first concrete frame beam 3, and connect the two first manual hoists on each frame column 4 to the lifting lugs 5 at the ends of the crossbeams of the two box girder segments. Move the first box girder segment 1 and the second box girder segment 2 horizontally closer to the gasifier and join the two box girder segments together from the splicing and joining position.

[0028] The technical solution claimed in this invention will be further clearly and completely described below with reference to a specific embodiment.

[0029] Taking a methanol technology upgrade project with an annual production capacity of 1 million tons as an example, the coal gasification (expansion) unit of this project has a frame composed of reinforced concrete and steel structures. The frame is 30 meters long from north to south, 34 meters wide from east to west, and 62.5 meters high, divided into 11 layers. Box beams are installed on the first concrete frame beam at a height of 19.470 meters. If traditional manufacturing and installation processes are used, the prefabrication and installation of single pieces and single frames will greatly increase the working time for hot work at heights and require additional working platforms, resulting in a higher probability of fire, explosion, and falling objects from heights, posing significant safety risks.

[0030] In this embodiment, based on the environmental factors of the construction site, each set of box girders is first fabricated into two sections at the processing plant: the first box girder section 1 and the second box girder section 2. Since the box girder installation location is at the 19.470-meter level of the gasification frame, a series of processes including unloading, relocation, welding of lifting lugs, traction, detachment, lifting and positioning, and assembly and welding are used to complete the hoisting, assembly, and installation of the pre-assembled box girder modules. The box girder is then lifted to 19.470 meters, separating the two sections to a position where the gasification furnace can be easily hoisted. Once the gasification furnace is hoisted above the design elevation, the two ends of the box girder are pushed back to the design position using pre-positioned manual hoists, and welding of the assembly nodes begins. After all the box girder welding is completed and passes non-destructive testing and acceptance, the gasification furnace is positioned. During the hoisting process, guide ropes are used to protect the box girder and ensure controllability during the lifting and positioning process.

[0031] First, before construction, construction preparations are carried out, followed by material and foundation acceptance, layout and cutting of materials, pre-assembly, assembly and welding, non-destructive testing of welding, spraying of rust-free anti-corrosion, and quality inspection and batch acceptance.

[0032] Foundation treatment and shim placement: (I) Foundation treatment: Before the box girder is installed, the foundation surface must be repaired, the embedded plate must be ground, and the shim placement area must be ground flat. The allowable deviation of the horizontality of the ground area is 3mm / m. The debris on the surface of the embedded plate must be cleaned. (II) Shim placement: At least one set of shims must be placed at the contact point between the box girder and each embedded plate. The shims must be in close contact with the embedded plate and the main beam of the module, and each set of shims shall not exceed four pieces.

[0033] Pre-assembly: (i) Prefabricate and assemble the crossbeams 6, longitudinal beams 7, and diagonal beams 8 on a steel platform according to the assembly sequence and process requirements to ensure the quality of their connection nodes and welding. (ii) Set up a pre-assembly platform at the processing plant according to the dimensions of the box girder. The box girder of the three gasifiers is fabricated and assembled in sequence to achieve reuse. All components of the crossbeams 6, longitudinal beams 7, and diagonal beams 8 of the two segmented box girder are pre-assembled as a whole at the splicing joint position using a solid assembly method. This is mainly to facilitate the inspection of the gap, horizontal deviation, verticality, and fit between the two splicing joints of the box girder. (iii) Before rust removal and corrosion prevention, a temporary pre-assembly is carried out. Through measurement and analysis, corrections are made for parts that exceed the allowable deviation to avoid rework.

[0034] Pre-assembly allows for the detection of quality deviations before shipment and timely adjustments to the corresponding connection nodes, enabling one-time on-site installation. This is an effective measure to ensure efficient on-site installation.

[0035] Assembly and welding:

[0036] The components of the box girder, including the horizontal beam 6, longitudinal beam 7, and diagonal beam 8, all include a lower flange, web, diaphragm, and upper flange, as well as necessary stiffening ribs.

[0037] The box girder is assembled using temporary tooling connecting plates. The assembly sequence is determined based on factors such as structural type and welding order: lower flange → diaphragm positioning welding → stiffening rib positioning welding → web positioning welding → rust removal and anti-corrosion coating of internal concealed parts → upper flange positioning welding.

[0038] During the assembly of the lower flange, the lower flange is placed on a platform, and the position of the web plate is located according to the drawings. Then, the web plate is vertically assembled onto the lower flange plate according to its position. After checking the verticality with a right-angle ruler, tack welding is performed. At the same time, tack welding is used to fix the web plate and the flange plate with temporary supports. Clamps are set on the assembly platform to force the weld to not deform.

[0039] When welding the diaphragm assembly, fillet welds are used to seal both sides of the clamping plate. To ensure the accuracy and quality of the web assembly, the diaphragm assembly adopts tack welding and is symmetrically divided. After the perpendicularity of the diaphragm and the lower flange is corrected with a right angle ruler, tack welding is performed. The clamping plate is installed after the diaphragm and the web are tack welded.

[0040] The diaphragm welding refers to the welding of the diaphragm to the lower flange, the two side webs, and the clamping plates. The welding is done by manual arc welding, which requires full penetration. After 50% of the welding is completed, the box girder is flipped over and the main weld between the lower flange and the two side webs is welded (the weld is done by submerged arc automatic welding). After 50% of the welding is completed, the welds on the three contact surfaces of the diaphragm inside the box girder are completed.

[0041] Before assembling the upper flange, the concealed parts inside the box girder should be welded first, then rust removed and painted as required, and sealed only after passing inspection. Assembling the upper flange only requires placing the straightened plate according to the drawings, and then symmetrically welding the welds between the upper flange and the two side webs using manual arc welding.

[0042] The selection principles for manual arc welding electrodes are as follows: E4315 electrode is used for welding between Q235B base materials; E5015 electrode is used for welding between Q345B base materials; H08MnA is used for welding between Q345B base materials using submerged arc welding wire; and HJ431 (H08A, 16-40 mesh) is used for welding between Q345B base materials using flux.

[0043] Following the steps described above, the box girder is prefabricated into the first box girder segment and the second box girder segment, respectively.

[0044] Second, the prefabricated box girders are transported to the site, and then hoisting equipment is set up to pull, detach, and lift the box girders to the reserved position.

[0045] On-site transport of box girder: (I) Based on the dimensions and weight of the box girder components, a 13-meter-long transport flatbed truck will be selected for transport. The road width, turning radius, and other factors that may affect construction must be surveyed in advance. (II) Based on the shape and horizontal center of gravity of the box girder, determine its placement position and fixing method on the transport flatbed truck to ensure the safety and stability of long-distance transport. The support points of the steel components on the vehicle, the length of the extension at both ends, and the binding method should all ensure that the steel components do not deform. Rubber pads should be laid on the contact surface of the box girder to ensure that the finished product is properly protected and the paint film layer is not damaged. (III) Since the box girder components are installed in a concrete frame, large hoisting equipment cannot be used. On-site unloading will be done directly onto the towing trailer. Therefore, it is necessary to prepare the site leveling, foundation treatment, and hoisting equipment preparation work in advance. Meanwhile, based on the shape, volume, and weight of the structure (frame), combined with the characteristics of the hoisting project and the site conditions, and on the premise of ensuring the safety and reliability of the hoisting project and the rationality of the process, and considering the reasonable use of machinery, it was determined that a 400T crawler crane with a gasification furnace would be used to complete the unloading work, since half of the overall weight of the box girder is about 28t.

[0046] Hoisting machine rigging arrangement:

[0047] (I) During the transportation of the box girder, the foundation of the horizontal traction walkway is prepared in advance. The steel trailer is placed on the steel plate, and grease is used for lubrication between the steel trailer and the steel plate. Since the roller is prone to swaying during front traction, while sliding friction is more stable during front traction, grease lubrication is chosen. After horizontal traction to the vertical lifting position, φ20mm gravel is backfilled along the horizontal entry route to the top of the slag discharge ditch (6m wide and the same length as the walkway slab). A 20t vibratory roller is used for compaction, and a 4m wide, 30m long, and 30mm thick steel plate is laid as the walkway slab and leveled. Angle steel of ∠75×8mm is welded to the edges of the walkway slab to ensure that the trailer travels in a straight line. After the box girder and gasifier are hoisted, the walkway slab needs to be removed and transported to the next box girder and gasifier hoisting position.

[0048] (II) Based on the characteristics of the gasification frame and the assembly position of the box girder, in order to ensure uniform stress after the box girder is hoisted into place, four 10t manual hoists and four 20t manual hoists are pre-installed on the frame beam 28.57m above the reserved position for hoisting the box girder. Two 10t manual hoists and two 20t manual hoists are used as second manual hoists; the other two 10t manual hoists and two 20t manual hoists are used as third manual hoists. After the box girder is hoisted and installed, they need to be removed and transported to the installation position of the next box girder.

[0049] (III) To ensure that the box girder can be horizontally assembled and closed immediately after the gasifier is raised above the installation elevation, lifting lugs will be welded to the embedded part 4 of the D-axis concrete frame column at a distance of 19.470 meters from the middle of the first concrete frame beam. These lugs will be used to mount four 5t manual hoists, which will serve as the first manual hoists. After the box girder is assembled and closed, the first manual hoists will need to be removed and the girder transported to the installation position of the next box girder.

[0050] (iv) Twelve steel wire ropes will be pre-positioned, four on the 28.57m concrete frame beam, four on each of the front and rear concrete frame beams, extending down to the 23.97m concrete frame beam to the box girder installation elevation. The remaining four steel wire ropes will be placed on the 18.47m concrete frame beam. Before hoisting the box girder, a temporary operating platform will be erected at the 18.47m level, with guardrails around it, to facilitate the installation of the box girder. Guardrails will also be installed around the 28.97m concrete platform to ensure the safety of construction personnel.

[0051] (v) The edges of the 28.57m concrete frame beams are smoothly transitioned with curved plates, which protects the finished concrete frame beams from damage and ensures that the wire ropes are not damaged. Since there are a total of 3 box girders, the lifting slings must be removed and reinstalled on the 28.57m concrete frame beam at the next box girder lifting position after each one has been hoisted, assembled and joined together.

[0052] Box girder traction lifting and hoisting:

[0053] (i) After the box girder is unloaded, it is directly hoisted onto the steel trailer used for hoisting the gasifier using a 400t crawler crane. Then, the first box girder segment 1 and the second box girder segment 2 are pulled, towed, and hoisted to the reserved position of the 19.470-meter concrete frame beam to ensure that the gasifier can be hoisted to the position smoothly.

[0054] (ii) The hoisting wire ropes for the box girder are respectively attached to four lifting lugs at the connection between the crossbeam 6 and the longitudinal beam 7 and at the middle of the longitudinal beam 7. The weight of the two box girder segments is 27.628Kg.

[0055] Box girder closure:

[0056] (a) The first box girder segment 1 and the second box girder segment 2 were respectively hoisted to the reserved position of the 19.470-meter concrete frame beam. The steel wire ropes were respectively tied to the connection between the cross beam 6 and the longitudinal beam 7 and the four lifting lugs 5 in the middle of the longitudinal beam 7. The hoisting and lifting adopted the gasification furnace double beam double cable + frame column anchor point method.

[0057] After the two box girder segments are hoisted to the reserved positions at the design elevation, the second manual hoist is connected to the lifting lug 5 on the first box girder segment 1, and the third manual hoist is connected to the lifting lug 5 on the second box girder segment 2.

[0058] Taking the second manual hoist connecting the lifting lug 5 on the first box girder segment 1 as an example, two manual hoists already tied to the 23.970-meter concrete frame beam are used to attach the wire ropes to the lifting lug 5 in the middle of the longitudinal beam 7. Two 10T manual hoists are selected at this point. Two manual hoists already tied to the 23.970-meter concrete frame beam are used to attach the wire ropes to the lifting lugs designed at the connection between the transverse beam 6 and the longitudinal beam 7. Two 20T manual hoists are selected to meet the overall load of the box girder and ensure force balance.

[0059] (ii) Use a 400t crawler crane to lift the gasifier into position above the installation elevation.

[0060] Third, after the box girder is assembled, leveled, and aligned, the assembly nodes are welded, and the welds are subjected to non-destructive testing.

[0061] After the gasifier is raised above the installation elevation, the box girder begins to close. Four 5T manual hoists are selected as the first manual hoists, and the wire ropes are respectively tied to the two ends of the crossbeam 6 of the two box girders and the four lifting lugs set at the corresponding embedded parts of the concrete frame column 4 of the D axis for the closing work.

[0062] During the tightening and closing process using four 5t manual hoists, four 10t manual hoists and four 20t manual hoists were adjusted and coordinated throughout the process to ensure the smooth closure of the box girder. The four 10t and four 20t manual hoists respectively lifted the first box girder segment 1 and the second box girder segment 2 from the first concrete frame beam, while the four 5t manual hoists provided horizontal traction.

[0063] Welding assembly nodes:

[0064] Two welding teams welded the 7-joint joints of the longitudinal beams of the two box girder sections respectively. The welding sequence was from the upper flange plate → lower flange plate → inner web plate → inner reinforcing plate of the lower flange plate → outer web plate reinforcing plate.

[0065] After the upper wing plate, lower wing plate, and inner web plate are welded, the first batch of non-destructive testing is carried out. After the outer web plate reinforcement plate is welded, the second batch of non-destructive testing is carried out.

[0066] The assembled box girder was leveled and aligned, and localized rust and corrosion protection was applied. Using a theodolite and level, shims were adjusted to strictly control the elevation and axis. The elevation and axis of the center point of each shim were accurately measured as the basic data for the overall installation of the box girder.

[0067] Fourth, the gasifier is in place and inspected and accepted.

[0068] The scope of protection claimed by this invention is not limited to the specific embodiments described above. For those skilled in the art, this invention can have various modifications and alterations. Any modifications, improvements, and equivalent substitutions made within the concept and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for installing box-type beams in a BGL gasifier unit, characterized in that, Includes the following steps: The box girder includes two parallel horizontal beams, two parallel longitudinal beams in the middle of the horizontal beams, and an inclined beam between the inner side of the longitudinal beams and the horizontal beams; the box girder is installed in a concrete frame after being lifted. Step 1: The box girder is prefabricated into two box girder segments and pre-assembled. During segment prefabrication, the splicing and joining position is planned in the middle of the longitudinal beam of the box girder, and the first box girder segment and the second box girder segment are prefabricated according to the splicing and joining position. Step two: Transport the two box girder segments to the construction site. Lift the first and second box girder segments from the bottom of the concrete frame onto the first concrete frame beam at the set elevation. Place the first and second box girder segments in the reserved positions on the front and rear sides of the first concrete frame beam, respectively. Leave space between the first and second box girder segments for lifting and installing the gasifier. Lift the gasifier to a position above the installation elevation. Step 3: Lift the first box girder segment and the second box girder segment away from the first concrete frame beam; set the first manual hoist on the side of the two concrete frame columns near the middle of the first concrete frame beam, and connect the two first manual hoists on each frame column to the lifting lugs at the ends of the crossbeams of the two box girder segments. Move the first box girder segment and the second box girder segment horizontally closer to the gasifier, and join the two box girder segments together from the splicing and joining position.

2. The method for installing the box girder of the BGL gasifier unit according to claim 1, characterized in that: In step two, after the two box girder segments are unloaded, they are hoisted onto the steel trailer using a crawler crane, and the steel trailer is then horizontally pulled to transport the two box girder segments to the ground at the bottom of the concrete frame.

3. The method for installing the box girder of the BGL gasifier unit according to claim 2, characterized in that: In step two, during the transportation of the box girder, the foundation of the walkway for horizontal traction is prepared in advance, and the steel trailer is placed on the steel plate, with grease used for lubrication between the steel trailer and the steel plate.

4. The method for installing the box girder of the BGL gasifier unit according to claim 1, 2 or 3, characterized in that: In step three, a second manual hoist and a third manual hoist are installed on the second concrete frame beam, which is higher than the height of the first concrete frame beam. After the two box girder segments are lifted to the reserved positions on the first concrete frame beam, the second manual hoist is connected to the lifting lug on the first box girder segment, and the third manual hoist is connected to the lifting lug on the second box girder segment. The first box girder segment and the second box girder segment are then lifted away from the first concrete frame beam.

5. The method for installing the box girder of the BGL gasifier unit according to claim 4, characterized in that: In step three, the lifting lugs on the first box girder connected to the second manual hoist are set at the connection points of the two crossbeams and longitudinal beams of the first box girder and in the middle of the two longitudinal beams.

6. The method for installing the box girder of the BGL gasifier unit according to claim 5, characterized in that: In step three, the lifting lugs on the second box girder connected to the third manual hoist are set at the connection points between the two crossbeams and longitudinal beams of the second box girder and in the middle of the two longitudinal beams.

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