A converter primary flue gas dry dust removal and gas cooling device

Abstract

This invention belongs to the field of environmental engineering technology, and specifically relates to a dry dust removal and gas cooling device for primary flue gas in a converter. The device includes a cylindrical body with an air inlet fixedly connected to its side wall and an ash hopper fixedly connected to its lower end. Multiple tubular structures are fixedly connected to the inner wall of the cylindrical body, forming a turbulent flow layer. The air inlet is located between the ash hopper and the turbulent flow layer. This invention significantly improves heat exchange efficiency through designs such as a herringbone-shaped annular gas collecting ring guiding the gas towards the center, a turbulent flow layer ensuring uniform gas distribution and sufficient contact with cooling water, and a high flow velocity at the throat further agitating the droplets. This ensures that the recovered gas temperature at the outlet of the gas cooler meets standards. Furthermore, when the gas is in full contact with the cooling water, the droplets capture dust from the gas, and the dehydration layer also captures the droplets and their entrained dust, further reducing the dust content of the gas in subsequent processes.

Description

Technical Field

[0001] This invention belongs to the field of environmental engineering technology, and in particular relates to a converter primary flue gas dry dust removal and coal gas cooling device. Background Technology

[0002] The primary flue gas of a converter mainly refers to the high-temperature, dust-laden, CO-containing brown flue gas generated during the steelmaking process in a converter. Its purification methods are mainly divided into two technical routes: wet dust removal and dry dust removal. The basic principle of dry dust removal for primary flue gas of a converter is that the high-temperature flue gas after passing through the vaporization flue enters the evaporative cooler and is sprayed with water for cooling, conditioning, and coarse dust removal, reducing its temperature from 900℃~1000℃ to about 200~260℃. After cooling, the flue gas enters the electrostatic precipitator for fine dust removal. The flue gas after fine dust removal enters the switching station and flues periodically with the steelmaking process in the converter. Depending on its gas quality, it is either recovered or released. The released flue gas enters the chimney for combustion and is then discharged into the atmosphere. The recovered gas enters the gas cooler for cooling (≤65℃) and is then stored in the gas holder.

[0003] Existing gas coolers typically use spray cooling and employ a vertical empty tower structure. Gas enters from the lower side of the tower, is cooled by internal spraying, and then exits from the top. Each spray layer has approximately 8 to 14 spray guns distributed around its circumference, with each spray gun extending into the tower. To ensure cooling effectiveness, two spray layers are set up (100-150% spray coverage), and the water volume is large.

[0004] Because the tower diameter is usually large (about 5 to 7 m), even if the spray guns arranged around the circumference of the tower wall are arranged in two layers, the gas entering from the side of the tower is prone to "short circuit" during the ascent, that is, the gas is not effectively covered by the spray cooling water, so the outlet gas temperature (≤65℃) sometimes cannot be guaranteed.

[0005] To address these issues, a dry dust removal and gas cooling device for primary flue gas in converters is proposed. Summary of the Invention

[0006] The purpose of this invention is to address the above-mentioned problems by providing a converter primary flue gas dry dust removal and gas cooling device.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a converter primary flue gas dry dust removal gas cooling device, comprising a cylinder, an air inlet fixedly connected to the side wall of the cylinder, an ash hopper fixedly connected to the lower end of the cylinder, multiple tube rod structures fixedly connected to the inner wall of the cylinder, the multiple tube rod structures forming a turbulent layer, the air inlet being located between the ash hopper and the turbulent layer, a throat being provided inside the cylinder, the throat being located above the turbulent layer, multiple spray guns being provided inside the throat, a dehydration layer being connected inside the cylinder, the dehydration layer being located above the throat, and an air outlet being fixedly connected to the upper end of the cylinder, the air outlet being located above the dehydration layer.

[0008] Preferably, the inner wall of the cylinder is fixedly connected with a herringbone-shaped annular air collecting ring, which is located 0.5m above the air inlet, and the radial width of the herringbone-shaped annular air collecting ring is 150-200mm.

[0009] Preferably, the diameter of the tube-rod structure is 150-200 mm.

[0010] Preferably, the cross-sectional area at the throat is one-half to one-third of the inner cross-sectional area of ​​the lower part of the cylinder.

[0011] Preferably, both ends of the throat are modified with a variable diameter, and the angle between the variable diameter sidewall and the gas flow direction is 30º to 45º.

[0012] Preferably, the tube-rod structure is a hollow thin-walled metal structure, which is connected to an external cooling water delivery device via a pipeline, and the pipeline is connected to a spray gun via the tube-rod structure.

[0013] Preferably, the multiple tube structures are arranged in a double-layered staggered manner within the cylinder, and the total flow area of ​​the gaps after the multiple tube structures are arranged at intervals and staggered is half of the cross-sectional area of ​​the lower part of the cylinder.

[0014] Preferably, the dehydration layer is a baffle demister or a tube bundle demister.

[0015] Preferably, the number of spray guns is 3 to 5, which are evenly distributed in a ring in the middle of the throat, and the spray direction of the spray guns is downward.

[0016] Preferably, the end of the air inlet connected to the cylinder is inclined downwards.

[0017] Compared with existing technologies, the advantages of a converter primary flue gas dry dust removal and gas cooling device are: 1. Reduce the number of spray guns and water volume, thereby reducing equipment investment and operating energy consumption: In the existing technology, due to the large diameter of the tower (about 5-7m), two spray layers are required, with 8-14 spray guns distributed in each layer to ensure spray coverage. This results in a large number of spray guns and a large water volume. This invention optimizes the spray design, which can reduce the number of spray guns used while ensuring effective coverage of the gas. This reduces the water volume per unit time, which not only reduces the purchase and maintenance costs of spray guns and other equipment, but also reduces water consumption and the operating energy consumption of related power systems, thereby improving the economic efficiency of equipment operation.

[0018] 2. Reduce the overall height of the tower, optimize the spatial layout, and improve the convenience of operation and maintenance: The lower spray layer of the existing cooler needs to be 1.8-2m higher than the upper edge of the air inlet, and the distance between the upper spray layer and the lower layer is ≥5m. In addition, the height of the tower's foundation structure itself results in a relatively high overall height. This invention improves the way the spray layer is set by setting a throat structure and setting only one layer of spray guns in the throat. While ensuring the natural and uniform diffusion of the rising airflow and sufficient heat exchange between the spray droplets and the gas, the number of spray layers is reduced, thereby reducing the overall design height of the tower. This not only reduces the equipment's occupation of the site, making it easier to plan the layout in a space, but also reduces the difficulty of high-altitude operations during equipment installation and maintenance, and improves the convenience and safety of the operation and maintenance process.

[0019] 3. Improve the uniformity of spray coverage and avoid gas "short circuit" to ensure stable outlet gas temperature: In the existing technology, due to the large diameter of the tower, the cooling water sprayed from the spray gun cannot completely cover the cross-section of the cylinder, which makes it easy for the gas to "short circuit" during the ascent, affecting the outlet recovered gas temperature. This invention, through the optimized design of the spray gun arrangement, can effectively improve the coverage and uniformity of the cooling water on the cross-section of the cylinder flow, ensuring that the gas fully contacts and exchanges heat with the spray droplets during the ascent, fundamentally avoiding the occurrence of "short circuit" phenomenon, thereby stabilizing and controlling the outlet recovered gas temperature, ensuring the quality of gas recovery, and providing reliable gas source conditions for subsequent gas utilization.

[0020] 4. Optimize airflow distribution and avoid the accumulation of harmful gases: By designing a herringbone-shaped annular gas collecting ring on the inner side of the tower wall, the "wall-attaching" effect of the airflow is effectively avoided, allowing the gas to gather in the middle of the tower. At the same time, the herringbone structure and the staggered arrangement of tubes and bars in the turbulence layer, as well as the throat design with variable diameters at the front and rear, are all conducive to the flow of gas and can prevent CO or oxygen from accumulating in corners, thus improving the safety of the unit's operation.

[0021] 5. Improved heat exchange efficiency: The turbulent layer consists of a double-layered, staggered arrangement of multiple rows of tube-rod structures. The cooling water sprayed from above forms a water film on the surface of the tubes, and even more cooling water forms a water curtain that falls rapidly between the tubes. When the high-temperature gas flows upward around the gaps between the tubes, its velocity increases, which breaks through the water film on the surface of the tubes and the water curtain flowing down from the gaps, greatly increasing the contact area and contact time between the high-temperature gas and the cooling water. In addition, a two-stage heat exchange is adopted. The cooling water first passes through the interior of the hollow thin-walled metal structure of the turbulent layer tubes, exchanges heat with the gas through the tube wall, and is then delivered to the throat spray gun for spray cooling, further improving the heat exchange efficiency.

[0022] 6. Achieve uniform gas distribution: After passing through the turbulent layer, the gas can be evenly distributed within the cross-section of the tower, which is beneficial for the stable operation of subsequent cooling, processing and other processes.

[0023] 7. Reduced resistance loss and reduced water volume: The throat designed in the middle of the tower body has a variable diameter treatment at the top and bottom of the section adjacent to the cylinder body, which reduces the resistance loss of the throat; and the cross-sectional area of ​​the throat is small, so only 3 to 5 spray guns are needed to effectively cover the gas flow surface, which greatly reduces the amount of water sprayed and saves water resources.

[0024] 8. Improve the contact rate between cooling water and gas: The spray gun sprays cooling water droplets downwards against the flow of gas. At the throat, the droplets and gas mix rapidly and evenly. The gas flow further breaks up the sprayed droplets, increasing the total surface area of ​​the droplets, thereby improving the contact rate between cooling water and gas.

[0025] 9. To prevent droplets from being carried out and ensure dehydration effect: The gas flow rate at the throat is designed to ensure that droplets fall normally and prevent them from being carried upwards out of the throat by the gas; at the same time, a dehydration layer is designed in the cylinder with a reduced diameter at the upper part of the throat, which can use a baffle plate demister or tube bundle demister, etc., to effectively remove a small number of droplets and dust entrained with the gas, thereby reducing the water content of the gas and increasing its calorific value while ensuring that the dust content of the gas is ≤5mg / Nm³. 3 . Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a converter primary flue gas dry dust removal and gas cooling device provided by the present invention.

[0027] In the diagram: 1. Cylinder; 2. Air inlet; 3. Ash hopper; 4. Tube-rod structure; 5. Turbulent layer; 6. Throat; 7. Spray gun; 8. Dehydration layer; 9. Air outlet; 10. Herringbone-shaped annular air collection ring. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0029] like Figure 1 As shown, a converter primary flue gas dry dust removal and gas cooling device includes a cylindrical body 1. An air inlet 2 is fixedly connected to the side wall of the cylindrical body 1. The end of the air inlet 2 connected to the cylindrical body 1 is inclined downwards. An ash hopper 3 is fixedly connected to the lower end of the cylindrical body 1. Multiple tube-rod structures 4 are fixedly connected to the inner wall of the cylindrical body 1. The diameter of the tube-rod structures 4 is 150-200 mm, and the multiple tube-rod structures 4 form a turbulent flow layer 5. The air inlet 2 is located between the ash hopper 3 and the turbulent flow layer 5. The cylinder 1 has a throat 6 inside, which is located above the turbulence layer 5. Multiple spray guns 7 are installed inside the throat 6. The number of spray guns 7 is 3 to 5, which are evenly distributed in a ring in the middle of the throat 6. The spray direction of the spray guns 7 is downward. The cylinder 1 is connected to a dehydration layer 8, which is located above the throat 6. The upper end of the cylinder 1 is fixedly connected to an air outlet 9, which is located above the dehydration layer 8. The dehydration layer 8 adopts a baffle plate demister or a tube bundle demister.

[0030] The inner wall of the cylinder 1 is fixedly connected with a herringbone-shaped annular air collecting ring 10. The herringbone-shaped annular air collecting ring 10 is located 0.5m above the air inlet 2, and the radial width of the herringbone-shaped annular air collecting ring 10 is 150-200mm.

[0031] The cross-sectional area at throat 6 is one-half to one-third of the lower inner cross-sectional area of ​​cylinder 1. Both the upper and lower ends of throat 6 are treated with diameter reduction, and the angle between the diameter reduction sidewall and the gas flow direction is 30º to 45º.

[0032] The tube-rod structure 4 is a hollow thin-walled metal structure. The tube-rod structure 4 is connected to the external cooling water conveying equipment through pipelines, and the pipelines are connected to the spray gun 7 through the tube-rod structure 4. Multiple tube-rod structures 4 are arranged in a double-layer staggered manner inside the cylinder 1. After the multiple tube-rod structures 4 are arranged in a staggered manner, the total flow area of ​​the gap is half of the cross-sectional area of ​​the lower part of the cylinder 1.

[0033] The operating principle of this invention is explained as follows: The converter primary flue gas dry dust removal gas cooling device is a vertical cylindrical tower structure. The gas enters the cylinder 1 obliquely downward from the lower air inlet 2 and naturally diffuses and rises. Guided by the herringbone-shaped annular gas collecting ring 10 on the inner side of the cylinder 1 at a height of about 0.5m above the air inlet 2, it gathers towards the middle of the cylinder 1. Subsequently, the gas flows around and passes through a multi-row tube rod structure arranged in a double layer and staggered at a height of about 0.5m above the herringbone-shaped annular gas collecting ring 10. The turbulent layer 5 is formed by a hollow, thin-walled metal tube-rod structure. Externally supplied cooling water first enters the tube-rod structure and undergoes primary heat exchange with the gas through the tube walls. Simultaneously, downward-flowing spray cooling water exchanges heat with the gas during its descent. The cascading spray water forms a water film on the surface of the tube-rod structure and a water curtain within the gaps between the tubes. As the gas flows upwards from below, its velocity increases when it breaks through the water film and water curtain, increasing the contact area with the cooling water. The gas flows through the turbulent layer 5 and is evenly distributed within the cross-section of the cylinder 1. Then, the gas enters the throat 6 in the middle of the cylinder 1. The throat 6, adjacent to the cylinder 1, uses a variable diameter design to reduce resistance loss. Due to the small cross-sectional area at the throat 6 (one-half to one-third of the lower inner cross-sectional area of ​​the cylinder 1), the gas flow velocity increases significantly. Three to five spray guns 7 arranged in the middle of the throat 6 spray cooling water droplets, which have undergone primary heat exchange inside the turbulent layer 5 tubes, downwards in a counter-current flow into the gas. The droplets... Throat 6 rapidly and uniformly mixes with the coal gas and is further abreastened by the gas flow, increasing the total surface area of ​​the droplets and the contact rate with the coal gas. The gas flow velocity at throat 6 ensures that the droplets fall normally without being carried away. The coal gas then enters the upper part of the cylindrical body 1, where the diameter is smaller than the lower part of the body 1. In this part, the dehydration layer 8 (using a baffle demister or tube bundle demister, etc.) removes a small amount of droplets and dust entrained with the coal gas. The treated coal gas has a dust content ≤5mg / Nm³. 3 The temperature is ≤65℃. The cooled gas is discharged from the air outlet 9 at the top of the cylinder 1, and the falling wastewater is discharged from the ash hopper 3 at the bottom of the cylinder 1.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A converter primary flue gas dry dust removal gas cooling device, comprising a cylinder (1), characterized in that, The side wall of the cylinder (1) is fixedly connected to an air inlet (2), and the lower end of the cylinder (1) is fixedly connected to an ash hopper (3). The inner wall of the cylinder (1) is fixedly connected to multiple tube rod structures (4), which together form a turbulent layer (5). The multiple tube rod structures (4) are arranged in a double-layer staggered manner inside the cylinder (1). The air inlet (2) is located between the ash hopper (3) and the turbulent layer (5). The cylinder (1) is provided with a throat (6). The cross-sectional area of ​​the throat (6) is one-half to one-third of the lower inner cross-sectional area of ​​the cylinder (1). The throat (6) is located above the turbulence layer (5). Multiple spray guns (7) are installed inside the throat (6). A dehydration layer (8) is connected inside the cylinder (1). The dehydration layer (8) is located above the throat (6). An air outlet (9) is fixedly connected to the upper end of the cylinder (1). The air outlet (9) is located above the dehydration layer (8).

2. The converter primary flue gas dry dust removal gas cooling device according to claim 1, characterized in that, The inner wall of the cylinder (1) is fixedly connected to a herringbone-shaped annular air collecting ring (10). The herringbone-shaped annular air collecting ring (10) is located 0.5m above the air inlet (2). The radial width of the herringbone-shaped annular air collecting ring (10) is 150-200mm.

3. The converter primary flue gas dry dust removal gas cooling device according to claim 1, characterized in that, The diameter of the tube-rod structure (4) is 150-200 mm.

4. The converter primary flue gas dry dust removal gas cooling device according to claim 1, characterized in that, The throat (6) is modified at both ends, and the angle between the modified sidewall and the gas flow direction is 30º~45º.

5. The converter primary flue gas dry dust removal gas cooling device according to claim 1, characterized in that, The tube-rod structure (4) is a hollow thin-walled metal structure. The tube-rod structure (4) is connected to an external cooling water conveying device through a pipeline, and the pipeline is connected to a spray gun (7) through the tube-rod structure (4).

6. The converter primary flue gas dry dust removal gas cooling device according to claim 1, characterized in that, After the multiple tube rod structures (4) are arranged in a staggered manner, the total flow area of ​​the gap is half of the cross-sectional area of ​​the lower part of the cylinder (1).

7. The converter primary flue gas dry dust removal gas cooling device according to claim 1, characterized in that, The dehydration layer (8) adopts a baffle plate demister or a tube bundle demister.

8. The converter primary flue gas dry dust removal gas cooling device according to claim 1, characterized in that, The number of spray guns (7) is 3 to 5, which are evenly distributed in a ring in the middle of the throat (6), and the spraying direction of the spray guns (7) is downward.

9. A converter primary flue gas dry dust removal and gas cooling device according to claim 1, characterized in that, The air inlet (2) is connected to the cylinder (1) at one end, which is inclined downward.

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