Flue connecting structure of side-blown furnace and waste heat boiler

Abstract

The invention discloses a flue connecting structure of a side-blown furnace and a waste heat boiler, a flue opening of the waste heat boiler is located above a flue opening of the side-blown furnace, a first flexible heat preservation material layer is arranged between the flue opening of the waste heat boiler and the flue opening of the side-blown furnace to serve as a first-stage sealing fire insulation structure, and the setting thickness of the first flexible heat preservation material layer is not smaller than 200 mm; a refractory brick layer is arranged on the outer side of the first flexible heat preservation material layer to serve as a second-stage sealing fire insulation structure, the refractory brick layer is arranged in the circumferential direction of the top of the flue opening of the side-blown boiler, the lower portion of the flue opening of the waste heat boiler is located in the space defined by the refractory brick layer, and the top of the refractory brick layer is at least 100 mm higher than the top of a lower collecting box of the waste heat boiler. And the refractory brick layer and the membrane wall at the top of the lower collecting box are sealed through a second flexible heat preservation material layer to form a third-stage sealing fire insulation structure. According to the flue connecting structure of the side blowing furnace and the waste heat boiler, the technical problem that in the prior art, a metal expansion joint is prone to damage, and consequently flue gas leaks is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of side-blown furnaces, and in particular relates to a flue connection structure of a side-blown furnace and a waste heat boiler. Background Art

[0002] Side-blown furnaces are widely used in non-ferrous metallurgical industries such as secondary lead, lead-zinc smelting, and copper smelting. To treat the high-temperature flue gas emitted by side-blown furnaces, waste heat boilers (HRSGs) are typically installed at the flue gas outlet to recover heat from the flue gas. The HRSG flue duct typically features a membrane wall with an external insulation layer. A lower header is located at the bottom of the membrane wall, equipped with downpipes and a blowdown pipe. The flue gas temperature at the side-blown furnace outlet is generally between 1100°C and 1300°C, cooling to approximately 350°C after passing through the HRSG. Due to temperature fluctuations before and after the HRSG is started, the HRSG flue outlet undergoes longitudinal and transverse contraction, with longitudinal contraction exceeding 10 cm. This results in a de facto movable joint between the side-blown furnace flue outlet and the HRSG flue outlet. Currently, the interface between the side-blown furnace flue outlet and the HRSG flue outlet typically utilizes a metal expansion joint made of 2520 stainless steel and filled with aluminum silicate fiber wool. However, the flue gas temperature in the flue port of the side-blown furnace is high and the working conditions are harsh. The parts of the metal expansion joint that come into contact with the high-temperature flue gas are mostly made of 2520 stainless steel. After long-term operation, 2520 stainless steel has the disadvantages of metal high-temperature fatigue, short service life, high maintenance difficulty, and high cost of use. In addition, the metal expansion joint is easily damaged locally, which will cause a lot of smoke around the side-blown furnace, affecting the safety of operators and the hygiene of the operating environment. Summary of the Invention

[0003] In response to the current technical problems, the present invention aims to provide a flue connection structure for a side-blown furnace and a waste heat boiler, which can solve the technical problem in the prior art that metal expansion joints are easily damaged, resulting in flue gas leakage.

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

[0005] A flue connection structure for a side-blown furnace and a waste heat boiler, wherein the flue opening of the waste heat boiler is located above the flue opening of the side-blown furnace, and its structural features are: a first flexible thermal insulation material layer is arranged between the flue opening of the waste heat boiler and the flue opening of the side-blown furnace as a first-level sealed fire-isolating structure, and the thickness of the first flexible thermal insulation material layer is not less than 200 mm; a refractory brick layer is arranged on the outside of the first flexible thermal insulation material layer as a second-level sealed fire-isolating structure, and the refractory brick layer is arranged circumferentially along the top of the flue opening of the side-blown furnace, and the lower part of the flue opening of the waste heat boiler is located in the space surrounded by the refractory brick layer, and the top of the refractory brick layer is at least 100 mm higher than the top of the lower collecting box of the waste heat boiler; the refractory brick layer and the membrane wall at the top of the lower collecting box are sealed by the second flexible thermal insulation material layer to form a third-level sealed fire-isolating structure.

[0006] A first flexible thermal insulation material layer is provided between the flue opening of the waste heat boiler and the flue opening of the side-blown furnace. The first flexible thermal insulation material layer has certain ductility and elasticity, and can absorb the longitudinal expansion and contraction of the waste heat boiler. The first flexible thermal insulation material layer is used as a first-level sealed fire-isolating structure. The first flexible thermal insulation material can be made of a high-temperature resistant material, such as an aluminum silicate fiber material. The refractory brick layer outside the first flexible thermal insulation material layer can be made of clay refractory bricks, and the refractory brick layer serves as a second-level sealed fire-isolating structure. The third flexible thermal insulation material layer provided between the refractory brick layer and the membrane wall can absorb the lateral expansion and contraction of the waste heat boiler, and the third flexible thermal insulation material layer serves as a third-level sealed fire-isolating structure. The flue connection structure of the side-blown furnace and the waste heat boiler of the present invention can effectively prevent the leakage of smoke and ensure the safety of operators and environmental hygiene by adopting a three-level sealed fire-isolating structure.

[0007] Preferably, an outer protective steel plate is provided on the outside of the refractory brick layer, the bottom of which is fixedly connected to the top of the flue port of the side-blown furnace, and the thickness of the outer protective steel plate is not less than 10 mm. The refractory brick layer is reinforced by providing the outer protective steel plate, thereby increasing the structural strength.

[0008] Preferably, expansion joints are provided between the four outer corners of the refractory brick layer and the outer protective steel plate, the width of the expansion joints is not less than 30 mm, and the expansion joints are filled with aluminum silicate fiberboard.

[0009] Preferably, the outer side of the outer guard steel plate is provided with a plurality of side reinforcing ribs, and the bottom of the outer guard steel plate is provided with a plurality of bottom reinforcing ribs. By providing the side reinforcing ribs and the bottom reinforcing ribs, the structural strength is further increased.

[0010] Preferably, a protective layer is provided on the inner side of the membrane wall, and the protective layer extends downward to the bottom of the lower header tank. The membrane wall and the lower header tank are protected by providing the protective layer.

[0011] Specifically, the protective layer and the membrane wall are integrally connected via a plurality of connecting pieces.

[0012] Preferably, the protective layer is made of wear-resistant and fire-resistant plastic material, the thickness of the protective layer is 50-60 mm, and the height of the protective layer is 500-1500 mm.

[0013] Preferably, the first flexible thermal insulation material layer is formed by laying multiple layers of aluminum silicate fiber felt, each layer of which is not less than 50 mm thick. Aluminum silicate fiber felt has good high temperature resistance and ductility, and can effectively absorb the expansion and contraction of the exhaust heat boiler flue outlet.

[0014] Preferably, the second flexible thermal insulation material layer is made of quartz sand or dry river sand.

[0015] Preferably, the lower header is provided with a sewage pipe and a downpipe, which respectively penetrate the refractory brick layer, and the penetrations are surrounded by a third flexible insulation material layer, which can be made of aluminum silicate fiber felt or high-temperature mortar.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The flue connection structure of the side-blown furnace and the waste heat boiler of the present invention adopts a three-level sealed fire isolation structure, which effectively prevents the leakage of flue gas and ensures the safety of operators and environmental hygiene.

[0018] 2. The flue connection structure of the side-blown furnace and the waste heat boiler of the present invention adopts non-metallic high-temperature resistant flexible materials (aluminum silicate fiber felt, quartz sand) to achieve expansion and contraction of the waste heat boiler flue interface, and has a long service life.

[0019] 3. The side-blown furnace and waste heat boiler flue connection structure of the present invention adopts a sealed fire isolation structure with simple construction and low procurement cost, which effectively reduces maintenance costs.

[0020] 4. The flue connection structure of the side-blown furnace and the waste heat boiler of the present invention is simple to maintain. After the furnace is put into production, only a small amount of quartz sand needs to be added. During the annual overhaul of the side-blown furnace, only aluminum silicate fiber felt and quartz sand need to be refilled. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the flue connection between the side-blown furnace and the waste heat boiler of the present invention;

[0022] Figure 2 yes Figure 1 Schematic diagram of the structure of the middle AA section;

[0023] Figure 3 yes Figure 1 Schematic diagram of the middle BB section structure;

[0024] Figure 4 yes Figure 1 Schematic diagram of the local sample structure;

[0025] Figure 5 yes Figure 1 Schematic diagram of the connection structure between the middle downcomer and the refractory brick layer;

[0026] Figure 6 yes Figure 5 Schematic diagram of the CC section structure;

[0027] Figure 7 yes Figure 1 Schematic diagram of the connection structure between the middle sewage pipe and the refractory brick layer;

[0028] Figure 8 yes Figure 7 Schematic diagram of the right view structure.

[0029] In the figure

[0030] 1- side-blown furnace flue outlet, 2- outer protective steel plate, 3- side reinforcement ribs, 4- bottom reinforcement ribs, 5- lower header, 6- drain pipe, 7- downcomer, 8- membrane wall, 9- outer insulation layer, 10- protective layer, 11- connecting piece, 12- refractory brick layer, 13- first flexible insulation material layer, 14- second flexible insulation material layer, 15- waste heat boiler flue outlet, 16- expansion joint, 17- third flexible insulation material layer. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. It should be noted that the embodiments and features of the embodiments may be combined unless they conflict. For ease of description, the words "upper," "lower," "left," and "right" appear below merely to indicate the directions of upper, lower, left, and right in the accompanying drawings and do not limit the structure.

[0032] like Figure 1 As shown, a flue connection structure of a side-blown furnace and a waste heat boiler in this embodiment is installed between the flue port 1 of the side-blown furnace and the flue port 15 of the waste heat boiler. An outer protective steel plate 2 is welded circumferentially on the top of the flue port 1 of the side-blown furnace. To ensure the structural strength, a plurality of side reinforcing ribs 3 are welded on the side of the outer protective steel plate 2, and a plurality of bottom reinforcing ribs 4 are welded on the bottom of the outer protective steel plate 2. The thickness of the outer protective steel plate 2 is not less than 10 mm. A protective layer 10 is attached around the inner wall of the flue port 15 of the waste heat boiler. The protective layer 10 is made of wear-resistant and fire-resistant plastic material. Figure 2As shown, the wear-resistant and fire-resistant plastic is connected to the membrane wall 8 as a whole through multiple connectors 11 pre-welded on the flat steel of the membrane wall 8 of the waste heat boiler, which protects the lower header 5 and the lower membrane wall 8 of the waste heat boiler. The connectors 11 are hook nails. The wear-resistant and fire-resistant plastic is about 1400mm high and 50-60mm thick. After the construction of the wear-resistant and fire-resistant plastic is completed, an expansion gap must be retained with the top of the side-blown furnace flue port 1. This expansion gap should be ≥200mm. The first flexible thermal insulation material layer 13 is filled in this expansion gap. The first flexible thermal insulation material layer 13 is made of aluminum silicate fiber felt. As the waste heat boiler expands, the aluminum silicate fiber felt is pressed downward. The aluminum silicate fiber felt serves as the first-level sealing and fire-isolating structure. The thickness of the aluminum silicate fiber felt used in the first flexible thermal insulation material layer 13 is not less than 50mm, and it is laid with multiple layers of aluminum silicate fiber felt. A circle of refractory bricks 12 is built on the outside of the aluminum silicate fiber felt close to the outer protective steel plate 2. The refractory brick layer 12 uses clay refractory bricks, which serve as the second-level sealing and fireproof structure. The size of clay refractory bricks is preferably 230 / 114 / 65. The top of the refractory brick layer 12 is built at a height of more than 100mm above the top of the lower header 5. Figure 3 As shown, four expansion joints 16 are left between the four corners of the outer ring of refractory bricks and the outer protective steel plate 2. The width of the expansion joint 16 is not less than 30mm, and the expansion joint 16 is filled with aluminum silicate fiberboard. Figure 4 As shown, the gap between the clay refractory bricks and the membrane wall 8 is filled with a second flexible thermal insulation material layer 14. The second flexible thermal insulation material layer 14 is made of quartz sand or dry river sand. The second flexible thermal insulation material layer 14 serves as a third-level sealing and fireproof structure. The top of the second flexible thermal insulation material layer 14 abuts against the outer thermal insulation layer 9 of the waste heat boiler. Figure 5 、 Figure 6 、 Figure 7 and Figure 8 As shown, the drainage pipe 6 and downcomer 7 connected to the waste heat boiler lower header 5 both penetrate the refractory brick layer 12. Space is left around the clay bricks during the laying process. After the bricks are laid, the gaps are filled with a third layer of flexible insulation material 17. This third layer of flexible insulation material can be made of high-temperature mortar or aluminum silicate fiber felt. The drainage pipe 6 penetrates the refractory brick layer 12 and is filled with high-temperature mortar. The downcomer 7 penetrates the refractory brick layer 12 and is filled with aluminum silicate fiber felt.

[0033] The contents described in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the invention, and are not used to limit the scope of the invention. After reading the present invention, various equivalent modifications to the embodiments made by those skilled in the art fall within the scope defined by the claims attached to the present invention.

Claims

1. A flue connection structure for a side-blown furnace and a waste heat boiler, wherein the flue opening (15) of the waste heat boiler is located above the flue opening (1) of the side-blown furnace, characterized in that: A first flexible thermal insulation material layer (13) is provided between the waste heat boiler flue port (15) and the side-blown furnace flue port (1) as a first-level sealing and fire-isolating structure, and the thickness of the first flexible thermal insulation material layer (13) is not less than 200 mm; A refractory brick layer (12) is provided on the outer side of the first flexible thermal insulation material layer (13) as a second-level sealed fire-insulating structure. The refractory brick layer (12) is circumferentially arranged along the top of the side-blown furnace flue port (1). The lower part of the waste heat boiler flue port (15) is located in the space surrounded by the refractory brick layer (12), and the top of the refractory brick layer (12) is at least 100 mm higher than the top of the lower header (5) of the waste heat boiler. The refractory brick layer (12) and the membrane wall (8) on the top of the lower header (5) are sealed via a second flexible thermal insulation material layer (14) to form a third-level sealed fire isolation structure.

2. The flue connection structure of the side-blown furnace and the waste heat boiler according to claim 1 is characterized in that: An outer protective steel plate (2) is provided on the outside of the refractory brick layer (12), the bottom of the outer protective steel plate (2) is fixedly connected to the top of the side-blown furnace flue port (1), and the thickness of the outer protective steel plate (2) is not less than 10 mm.

3. The flue connection structure of the side-blown furnace and the waste heat boiler according to claim 2, characterized in that: Expansion joints (16) are provided between the four outer corners of the refractory brick layer (12) and the outer protective steel plate (2). The width of the expansion joints (16) is not less than 30 mm, and the expansion joints (16) are filled with aluminum silicate fiberboard.

4. The flue connection structure of the side-blown furnace and the waste heat boiler according to claim 2, characterized in that: The outer side of the outer protective steel plate (2) is provided with a plurality of side reinforcing ribs (3), and the bottom of the outer protective steel plate (2) is provided with a plurality of bottom reinforcing ribs (4).

5. The flue connection structure of the side-blown furnace and the waste heat boiler according to claim 1, characterized in that: A protective layer (10) is provided on the inner side of the membrane wall (8), and the protective layer (10) extends downward to the bottom of the lower header (5).

6. The flue connection structure of the side-blown furnace and the waste heat boiler according to claim 5, characterized in that: The protective layer (10) and the membrane wall (8) are integrally connected via a plurality of connecting pieces (11).

7. The flue connection structure of the side-blown furnace and the waste heat boiler according to claim 5, characterized in that: The protective layer (10) is made of wear-resistant and fire-resistant plastic material, the thickness of the protective layer (10) is 50-60 mm, and the height of the protective layer (10) is 500-1500 mm.

8. The flue connection structure of the side-blown furnace and the waste heat boiler according to any one of claims 1 to 7, characterized in that: The first flexible thermal insulation material layer (13) is formed by laying multiple layers of aluminum silicate fiber felt material, and the thickness of each layer of aluminum silicate fiber felt is not less than 50 mm.

9. The flue connection structure of the side-blown furnace and the waste heat boiler according to any one of claims 1 to 7, characterized in that: The second flexible thermal insulation material layer (14) is made of quartz sand or dry river sand.

10. The flue connection structure of the side-blown furnace and the waste heat boiler according to any one of claims 1 to 7, characterized in that: The lower header (5) is provided with a sewage pipe (6) and a downcomer (7), which respectively penetrate the refractory brick layer (12), and the penetration points are surrounded by a third flexible thermal insulation material layer (17).

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