A double series kiln tail frame layer adding system and method

Abstract

The invention discloses a double series kiln tail frame layer adding system and method, including a double span multi-layer frame structure composed of steel tube concrete columns, beams, diagonal braces and platform plates, the bottom steel tube concrete columns are provided with outer column feet, the outer column feet are reinforced around and extended upward to more than half the height of the floor to form heightened column feet, and reinforcement beams are arranged between the heightened column feet and between the steel tube concrete columns of the middle layer, the reinforcement beams are offset at the intersection with the steel diagonal braces, and a layer of frame structure is added on the top of the frame. The invention can improve the structural safety, reduce the construction difficulty, shorten the transformation period and reduce the cost while adding layers to the original structure.

Description

Technical Field

[0001] The invention relates to a layer adding and reinforcing technology, in particular to a double series kiln tail frame layer adding system and method. Background Art

[0002] Preheater is one of the main equipment in cement plant. Conventional double series preheater kiln tail generally has five-stage preheater cyclone. Each stage of cyclone occupies one layer in the kiln tail frame structure, with a layer height of about 12 to 15 meters. With the improvement of environmental protection requirements, conventional five-stage preheaters cannot meet low-carbon environmental protection requirements due to their high energy consumption. Changing the kiln tail preheater to six-stage can reduce about 5kg of standard coal. The significance of changing the five-stage kiln tail preheater to six-stage is to reduce the gas temperature out of the preheater and reduce the heat loss carried away by the hot flue gas of the preheater system, thereby improving the heat exchange efficiency of the preheater, reducing the heat consumption of the system, and reducing the amount of coal used for combustion, thereby achieving CO2 emission reduction in cement production.

[0003] It is very difficult to implement the change of the five-stage to six-stage preheater at the tail of the kiln, mainly because of the reinforcement of the frame at the tail of the kiln, and the focus is on the reinforcement of the steel tube concrete column at the tail of the kiln. According to the process plan, the five-stage preheater is changed to a six-stage preheater, and it is necessary to add another main floor to the top of the original tower. Take a factory's 5000t / d clinker cement production line as an example: the added floor height is about 12 meters, and the vertical load of equipment is about 1100 tons. Because the height of the tower increases, the wind load and seismic load that the tower needs to withstand also increase, which leads to the insufficient bearing capacity of the original tower, and the steel frame beams, steel supports and steel tube concrete columns all need to be reinforced. It is not easy to reinforce the frame nodes of steel tube concrete columns, and it is difficult to achieve the model assumed by the structural engineer. Unsatisfactory reinforcement will affect the normal use of the tower.

[0004] Taking the tower middle column (GZ2B, the first layer of steel tube concrete column) as an example, the original 5-stage preheater kiln tail tower column calculation:

[0005] First-floor concrete-filled steel tube column: axial compressive bearing capacity verification M = 118.45, N = 17358.42 < N u =17361.33, meets the requirements;

[0006] Second-story steel tube concrete column: axial compressive bearing capacity verification M = 167.11, N = 16146.19 < N u =16151.66, meets the requirements;

[0007] The third-story steel tube concrete column: axial compressive bearing capacity verification M = 508.49, N = 11519.3 < N u =12840.87, meets the requirements;

[0008] After changing to 6-stage preheater, calculation of kiln tail tower column:

[0009] First-floor concrete-filled steel tube column: axial compressive bearing capacity verification: M = 138.98, N = 19975.25 > N u =17361.33, does not meet the requirements (over 15%);

[0010] Second-story steel tube concrete column: axial compressive bearing capacity verification M = 289.4, N = 18867.91> N u =16643.91, does not meet the requirements (exceeding 13.4%);

[0011] The third-story steel tube concrete column: axial compressive bearing capacity verification M = 335.74, N = 15524.48 > N u =15009.95, does not meet the requirements (exceeds 3.4%);

[0012] Fourth-floor steel tube concrete column: axial compressive bearing capacity verification M = 642.85, N = 11602.55 < N u =12362.34, meets the requirements.

[0013] At present, there are two main methods for reinforcing steel tube concrete columns: one is to increase the sleeve index θ of the steel tube concrete and directly attach steel plates to the outside of the steel tube column for reinforcement; the other is to increase the cross-sectional area A of the steel tube concrete. c , a steel pipe column is placed outside the steel pipe column, and the middle is filled with high-strength castable.

[0014] The first reinforcement method: the round steel pipe must be rolled in the factory, welded with ear plates, cut into several sections, and then cut into two halves. The cuts must be beveled. During transportation, the packaging must be done well to prevent deformation. On-site installation is quite difficult. First, the paint on the outer wall of the steel pipe column must be removed. The tension bolts must be properly stressed and can fit the original pipe wall in full line before welding. The construction work is mainly high-altitude welding, which requires a lot of welding work. The gap between the new and old steel pipes and the quality of the weld will affect the ferrule effect of the steel pipe concrete and the bearing capacity of the steel pipe concrete column.

[0015] The second reinforcement method: The round steel pipe must be rolled in the factory (construction measures: welding ear plates for easy lifting), first cut into several sections, then cut into two halves, and the cuts must be beveled. During transportation, it must be well packaged to prevent deformation. It is quite difficult to install on site. The steel pipe must be connected vertically before welding. The construction work is mainly high-altitude welding, which requires a lot of welding work and is difficult to ensure the quality of the weld. The gap between the new and old steel pipes is poured densely with grouting material. If the construction quality is compromised, it will affect the sleeve effect of the steel pipe concrete and the bearing capacity of the steel pipe concrete column.

[0016] The above two methods have obvious defects in the reinforcement of the beam-column nodes of the kiln tail frame. The outstanding advantage of the steel tube concrete column is the ferrule effect of the steel tube, which gives full play to the good compressive performance of concrete. If the quality of the node construction is not good enough, the ferrule effect is poor, and the assumed conditions of the modeling calculation are not met, it will leave hidden dangers to the safety of the structure. The first reinforcement method: In the beam-column node area, the steel pipe must be cut into 4 petals, stuffed between the frame beams, and the steel plates must be planed and tightened before welding. Some welds are overhead welding, and high construction accuracy is required. The second reinforcement method: On the one hand, in the beam-column node area, the steel pipe must be cut into 4 petals, stuffed between the frame beams, and a gap must be left to pour the grouting material. It is difficult to pour the grouting material densely. The steel plates must be planed and tightened before welding. Some welds are overhead welding, and high construction accuracy is required. On the other hand, if the steel tube concrete column is not destroyed, the newly added steel casing will not work; the newly added steel casing will only work when the original steel tube concrete column is destroyed, but if the new node is not well made, the tower may collapse, with extremely serious consequences.

[0017] Process engineers at home and abroad have been thinking and researching about changing the five-stage preheater to a six-stage preheater for more than 10 years. However, because the conventional structural design only considers the load of the five-stage preheater and does not consider the load of the six-stage preheater, there is not enough safety margin to bear the load of the six-stage preheater. Therefore, most structural engineers do not accept adding floors directly.

[0018] In recent years, the country has been increasingly supporting energy conservation and emission reduction. The requirement to change the five-stage preheater of cement plants to a six-stage preheater has become more urgent. At present, process engineers at home and abroad have roughly two plans to implement: one method is to add a new frame on one side of the original frame to support the newly added six-stage decomposition furnace (the original five-stage decomposition furnace is removed). Due to limited space, the newly added frame cannot be put on the ground and can only be supported by huge diagonal braces. At the same time, the side columns of the original frame connected to the new frame also increase a lot of external force, reducing the safety of the original side columns. Another method is to add layers directly to the original structure, and the structural engineer is responsible for reinforcing the insufficient parts of the structure.

[0019] Therefore, a solution that can satisfy process engineers' needs of adding layers directly to the original structure while also ensuring structural safety is of great significance.

[0020] In addition, the existing technical measures are all aerial operations. Whether it is the external steel plate method or the increased cross-section method, the steel tube concrete column is difficult to construct, and the construction quality is difficult to guarantee, which poses a safety hazard. The transformation and reinforcement of the kiln tail frame from level 5 to level 6 is generally carried out during the cement plant's shutdown and maintenance period. The existing reinforcement plan needs to wait until the kiln is shut down and unloaded before it can be implemented. The reinforcement cycle is long and cannot meet the actual production needs of the cement plant. Summary of the invention

[0021] Purpose of the invention: The present invention aims to provide a double-series kiln tail frame layer-adding system and method which can add layers to the original structure and improve structural safety, reduce construction difficulty, and shorten the transformation cycle.

[0022] Technical solution: The double-series kiln tail frame layer-adding system described in the present invention includes a double-span multi-layer frame structure composed of steel tube concrete columns, beams, diagonal braces and platform plates. The bottom steel tube concrete columns are provided with outer column footings, which are reinforced all around and extended upward to more than half the height of the floor to form heightened column footings, and reinforcement beams are arranged between the heightened column footings and between the middle-layer steel tube concrete columns. The reinforcement beams are offset at the intersection with the steel diagonal braces, and an additional layer of frame structure is arranged on the top of the frame.

[0023] Preferably, the heightened column foot extends upward to 1 m above the half-story height.

[0024] Preferably, a corbel beam is provided at the connection between the height-increasing column foot and the reinforcement beam, the corbel beam is arranged at a half-story height position, and the connection node between the corbel beam and the reinforcement beam is buried in the height-increasing column foot.

[0025] Preferably, the reinforcement beam is arranged at a half-story height of the steel tube concrete column in the middle layer of the frame.

[0026] Preferably, the reinforcement beams are arranged at 1 / 3 and 2 / 3 of the height of the steel tube concrete columns in the middle layer of the frame.

[0027] Preferably, the reinforcement beams are arranged at all axis lines of the frame structure and are offset at locations where they conflict with the steel diagonal braces to avoid the steel diagonal braces.

[0028] Preferably, the reinforcement beams are arranged at the mid-span positions between the F, B, C axes and the E, G axes of the frame structure.

[0029] Preferably, short diagonal braces are arranged between adjacent reinforcement beams in the middle spans of the middle layer F, B, C axes and E, G axes, and short branch beams are arranged at the intersection nodes of the F axis with the A and D axes.

[0030] Preferably, a column corbel is provided at the connection between the steel tube concrete column in the middle layer of the frame and the reinforcement beam.

[0031] The double-series kiln tail frame layer-adding and reconstruction method of the present invention comprises the following steps:

[0032] (a) Design the parameters of the increased column base, reinforced beams, corbel beams, short diagonal braces, short branch beams, column corbels and an additional layer of frame structure according to safety requirements;

[0033] (b) Remove the concrete on the top surface of the column foot of the bottom steel tube concrete column to expose the steel bars, straighten the longitudinal bars, remove the paint on the steel tube column surface within the height range above half a floor, weld the longitudinal bars, stirrups and rivets, and weld the corbel beam at the location where the reinforcement beam is set at half a floor height. The reinforcement beam is set on the corbel beam, and the conflicting part between the reinforcement beam and the steel diagonal brace is offset inward to avoid the steel diagonal brace. Finally, cast the outer cover with concrete so that the connection node between the reinforcement beam and the corbel beam is buried in the height-increasing column foot.

[0034] (c) Column corbels are set at the locations where reinforced beams are arranged in the middle layer of the frame concrete tube, and the reinforced beams are connected. The locations where the reinforced beams conflict with the steel diagonal braces are rotated and offset to avoid the steel diagonal braces, and short diagonal braces and branch short beams are set to enhance the node stiffness.

[0035] (d) Take safety measures, dismantle the top floor and intermediate supports of the original framework, and add a new layer of framework structure and equipment according to the actual construction drawings.

[0036] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: 1. While adding layers to the original structure, it effectively reduces the inter-layer lateral displacement of the new structure, the stress ratio of the steel tube concrete column and the support, and improves the safety of the structure; 2. It avoids the reinforcement of the core area of ​​the frame node, reduces the workload of high-altitude welding, reduces the construction difficulty, and improves the construction quality; 3. It avoids time-consuming processes such as large-scale paint removal, steel bonding, and grouting. Some processes can be carried out before the kiln is shut down for maintenance, and can also be interspersed with the upper dismantling, installation, and reinforcement work, effectively shortening the transformation cycle; 4. It avoids the removal and re-filling of part of the steel platform connected to the steel column, reducing the amount of work and construction time; 5. Compared with the existing reinforcement technology, the cost of reinforcement work can be reduced by more than 50%. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a plan view of the half-layer reinforcement of the steel tube concrete column at the bottom of the frame according to the first embodiment of the present invention;

[0038] Figure 2 This is a half-layer reinforcement plan of a second-layer steel tube concrete column in a frame according to the first embodiment of the present invention;

[0039] Figure 3 This is a half-layer reinforcement plan of a three-layer steel tube concrete column frame according to the first embodiment of the present invention;

[0040] Figure 4 It is an elevation view of the E and G axes of the frame of the first embodiment of the present invention;

[0041] Figure 5 This is an elevation view of the frame F axis of the first embodiment of the present invention;

[0042] Figure 6 This is a structural diagram of the frame heightening column foot of the present invention;

[0043] Figure 7 It is a plan view of the half-layer reinforced beam-column nodes of the second and third-layer concrete-filled steel tube columns of the frame of the present invention;

[0044] Figure 8 This is an elevation view of the half-layer reinforced beam-column node of the second and third-layer steel tube concrete columns of the frame of the present invention;

[0045] Fig. 9 This is a plan view of the half-layer reinforcement of the steel tube concrete column at the bottom of the frame in the second embodiment of the present invention;

[0046] Fig.10 It is an elevation view of the E and G axes of the frame of the second embodiment of the present invention;

[0047] Fig.11 This is a vertical view of the frame F axis of the second embodiment of the present invention. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0049] Embodiment 1

[0050] like Figure 1 , 4 -6, a double series kiln tail frame layer-adding system described in the present invention includes chiseling off the top surface concrete of the outer column foot 1 to expose the steel bar, straightening the original longitudinal bar, removing the paint on the surface of the steel tube concrete column within the range of half-story height plus 1 meter, welding the longitudinal bar, stirrups and welding nails, welding the corbel beam 5 at the position where the reinforcement beam 3 is set at the half-story height, the reinforcement beam 3 is arranged at the position of the middle span of the axis F, B, C and the axis E, G of the frame structure, and is set on the corbel beam 5, and finally C40 concrete is poured on the outer package to form the heightened column foot 2, the heightened column foot 2 extends upward to 1m above the half-story height, and the connection node between the reinforcement beam 3 and the corbel beam 5 is buried in the heightened column foot 2, as shown in FIG. Figure 6 shown.

[0051] like Figure 2 , 4 -5, a reinforcing beam 3 is set between the steel tube concrete columns at the second and a half-story height of the frame, and the reinforcing beam 3 is arranged at all the axes of the frame structure. The reinforcing beam 3 and the steel diagonal brace 4 are rotated and offset at the conflicting points to avoid the original steel diagonal brace 4, and short diagonal braces 6 are set between adjacent reinforcing beams 3 in the middle spans of the F, B, C axes and the E, G axes. A branch short beam 7 is set at the intersection node of the F axis with the A, D axes to enhance the node stiffness.

[0052] like Figure 3 , 4-5, a reinforcement beam 3 is set between the steel tube concrete columns at the third and half-story height of the frame. The reinforcement beam 3 is arranged in the middle span of the F, B, C axis and the E, G axis of the frame structure. The reinforcement beam 3 and the steel diagonal brace 4 are rotated and offset at the conflict point to avoid the steel diagonal brace 4, and short diagonal braces 6 are set between adjacent reinforcement beams 3. The connection between the steel tube concrete columns of the second and third floors of the frame and the reinforcement beam 3 is provided with a column bracket 8, and the column bracket 8 is as shown in FIG. Figure 7-8 shown.

[0053] like Figure 4-5 As shown, the floor and the middle support of the sixth floor are removed, and an additional frame structure 9 is added on the top of the frame according to the actual construction drawing.

[0054] Embodiment 2

[0055] As another preferred embodiment, the double-series kiln tail frame layer-adding system of the present invention comprises chiseling off the top surface concrete of the outer column foot 1 to expose the steel bar, straightening the original longitudinal bar, removing the paint on the surface of the steel tube concrete column within the range of half-story height plus 1 meter, welding the longitudinal bar, stirrups and rivets, and welding the corbel beam 5 at the position where the reinforcement beam 3 is set at the half-story height. Figure 6 The reinforcement beam 3 is arranged at all axis positions of the frame structure and is set on the corbel beam 5. The conflicting part with the steel diagonal brace 4 is offset inward to avoid the steel diagonal brace 4, as shown in FIG. Fig. 9 Finally, C40 concrete is poured outside to form the heightened column foot 2, which extends upward to 1m above the half-story height, and the connection node between the reinforcement beam 3 and the corbel beam 5 is buried in the heightened column foot 2.

[0056] Two reinforcement beams 3 are set between the steel tube concrete columns at the 1 / 3 and 2 / 3 height positions of the second floor of the frame, such as Figure 10-11 As shown. The reinforcement beams 3 are arranged at all axes of the frame structure, and the reinforcement beams 3 are rotated and offset at the collision points with the steel diagonal braces 4 to avoid the steel diagonal braces 4, and short diagonal braces 6 are arranged between adjacent reinforcement beams 3 in the middle spans of the F, B, C axes and the E, G axes, and branch short beams 7 are arranged at the intersection nodes of the F axis and the A, D axes to enhance the node stiffness.

[0057] Reinforced beams 3 are arranged between the steel tube concrete columns at the third and a half-story height of the frame. The reinforced beams 3 are arranged in the middle span of the F, B, C axes and the E, G axes of the frame structure. The reinforced beams 3 are rotated and offset at the collision points with the steel diagonal braces 4 to avoid the steel diagonal braces 4, and short diagonal braces 6 are arranged between adjacent reinforced beams 3. Column brackets 8 are provided at the connection points between the steel tube concrete columns of the second and third floors of the frame and the reinforced beams 3.

[0058] The floor and the middle support of the sixth floor are removed, and an additional frame structure 9 is added on the top of the frame according to the actual construction drawing.

[0059] Taking the reinforcement method of the steel tube concrete column at the kiln tail of a factory in Guangdong as an example, when the steel plate is directly attached to the outside of the steel tube column to improve the sleeve index θ of the steel tube concrete, 140 tons of steel is required. However, because the required steel plate thickness is large and does not meet the construction requirements, this reinforcement method is not adopted. The current reinforcement method is to cover the steel tube column with a steel tube column, and fill the middle with high-strength castables to increase the cross-sectional area A of the steel tube concrete. c , 245 tons of steel and 55 cubic meters of high-strength grouting material are required. When the reinforcement and reconstruction scheme in the second embodiment of the present invention is adopted, only 90 tons of steel and 100 cubic meters of concrete are required, and the cost is reduced by more than half.

Claims

1. A double-series kiln tail frame layer-adding system, comprising a double-span multi-layer frame structure consisting of steel tube concrete columns, beams, inclined supports and platform plates, wherein the steel tube concrete columns at the bottom are provided with external column footings (1), characterized in that: The concrete on the top surface of the outer column foot (1) is chiseled off to expose the steel bars, the original longitudinal bars are straightened, the longitudinal bars, stirrups and welding nails are welded within a height range above half the height of the floor, the outer column foot (1) is reinforced on all sides and extended upward to above half the height of the floor to form an increased column foot (2), and a reinforcement beam (3) is arranged between the increased column foot (2) and between the intermediate layer of steel tube concrete columns, the reinforcement beam (3) is offset at the intersection with the steel diagonal brace (4), and an additional layer of frame structure is provided on the top of the frame; a corbel beam (5) is provided at the connection between the increased column foot (2) and the reinforcement beam (3), the corbel beam (5) is arranged at a half-height position, the reinforcement beam (3) is arranged on the corbel beam (5), and the connection node between the corbel beam (5) and the reinforcement beam (3) is buried in the increased column foot (2); The plan view of the double-series kiln tail frame layer-adding system includes horizontal axes A, B, C, and D arranged in parallel from bottom to top, and vertical axes E, F, and G arranged in parallel from left to right, and the horizontal axes and the vertical axes are orthogonal to each other, and the intersection nodes divide the axes into a plurality of spans; the reinforcement beams (3) are arranged at all axes of the frame structure, or arranged at the positions of the middle spans between the axes F, B, and C and the axes E and G of the frame structure; short diagonal braces (6) are arranged between adjacent reinforcement beams (3) in the middle spans between the axes F, B, and C and the axes E and G of the middle layer, and branch short beams (7) are arranged at the intersection nodes between the axes F and the axes A and D.

2. The layering system according to claim 1, characterized in that: The height-enhancing column foot (2) extends upward to 1 m above the half-story height.

3. The layering system according to claim 1, characterized in that: The reinforcement beam (3) is arranged at a half-story height of the steel tube concrete column in the middle layer of the frame.

4. The layered system according to claim 1, characterized in that: The reinforcement beams (3) are arranged at positions of 1 / 3 and 2 / 3 of the height of the steel tube concrete columns in the middle layer of the frame.

5. The layered system according to claim 1, characterized in that: A column corbel (8) is provided at the connection between the steel tube concrete column in the middle layer of the frame and the reinforcement beam (3).

6. A layer adding method for a double series kiln tail frame layer adding system according to any one of claims 1 to 5, characterized in that: The following steps are involved: (a) Designing parameters of the heightened column foot (2), the reinforcement beam (3), the corbel beam (5), the short diagonal brace (6), the branch short beam (7) and the column corbel (8) according to safety requirements; (b) chiseling away the top surface concrete of the outer column foot (1) of the bottom steel tube concrete column to expose the steel bars, straightening the longitudinal bars, removing the paint on the surface of the steel tube concrete column within the height range above half the floor height, welding the longitudinal bars, stirrups and welding nails, welding the corbel beam (5) at the position where the reinforcing beam (3) is set at the half-floor height, the reinforcing beam (3) is set on the corbel beam (5), and the conflicting part between the reinforcing beam (3) and the steel diagonal brace (4) is offset inward to avoid it, and finally pouring the outer cover with concrete so that the connection node between the reinforcing beam (3) and the corbel beam (5) is buried in the height-increasing column foot (2); (c) a column bracket (8) is provided at the location where the steel tube concrete column in the middle layer of the frame is connected to the reinforcement beam (3), the reinforcement beam (3) is connected, the collision location between the reinforcement beam (3) and the steel diagonal brace (4) is rotated and offset to avoid the steel diagonal brace (4), and a short diagonal brace (6) and a branch short beam (7) are provided; (d) Take safety measures, dismantle the top floor and intermediate supports of the original frame, and add a new layer of frame structure and equipment according to the actual construction drawings.

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