Tail gas treatment device for aluminum casting process

Abstract

A tail gas treatment device for an aluminum casting process comprises a desulfurization tower body, a flue gas outlet, a flue gas inlet, a swirler, spraying layers, a demister, a manhole door, a sewage draining exit, a bottom fixing seat, a four-stage sedimentation tank, a circulating water pump, a reagent pipeline and a slurry pipeline, and the swirler, the two spraying layers and the demister are sequentially arranged in an inner cavity of the desulfurization tower body from bottom to top; the spraying layer is arranged right above the swirler, the interval height between the spraying layer and the swirler is determined by the spraying angle of the spraying head, a spraying main pipe and a spraying branch pipe are arranged on the spraying layer, and the interval height between the spraying layer is determined by the total number of the spraying layers and the spraying angle of the spraying head; a flue gas outlet is formed in the top end of the desulfurization tower body, a flue gas inlet and a manhole door are arranged at the bottom of the desulfurization tower body, and a drain outlet is formed in the side wall of the bottom of the desulfurization tower body; and the four-stage sedimentation tank is connected with the desulfurization tower body through a drain outlet. According to the utility model, the desulfurization effect is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of flue gas desulfurization and relates to a tail gas treatment device for an aluminum casting process. Background Art

[0002] Aluminum alloy is the second most widely used metal after steel. It has low density, high strength, good plasticity, can be processed into various profiles, and has excellent electrical conductivity, thermal conductivity and corrosion resistance. Therefore, it is widely used in electronics, machinery, automobiles, energy and other fields. In the modern aluminum alloy smelting industry, aluminum plates that can be formed and applied to the market usually need to be heated to liquid aluminum. Since the raw materials contain impurities such as sulfur, toxic and harmful sulfur-containing gases will be generated during the smelting process. At the same time, it will also contain a large amount of solid particles and dust. If they are discharged without treatment, they will cause irreversible damage to the environment. Therefore, it is necessary to purify the tail gas generated during the production process.

[0003] At present, the common tail gas treatment device in the aluminum casting process is a desulfurization tower device, which needs to pass the sulfur-containing tail gas into the desulfurization tower, and react with the sulfur-containing substances in the tail gas by spraying alkaline slurry to achieve the purpose of desulfurization. However, some existing desulfurization towers, spray layers and other tail gas treatment devices are fixed on the inside of the desulfurization tower body, which is inconvenient to disassemble. At the same time, the inspection holes are not reasonably set, and impurities are easily accumulated after long-term use, causing the problem of spray head clogging, which makes maintenance problems difficult to handle. At the same time, the existing desulfurization tower has a single structure and a random layout. There is an uncovered spray blind area, and the sulfur-containing tail gas introduced cannot fully contact with the alkaline slurry, resulting in poor tail gas treatment effect. Summary of the invention

[0004] In order to overcome the shortcomings of the existing technology, the utility model discloses a tail gas treatment device for aluminum casting process, optimizes the internal structure of the desulfurization tower, and at the same time increases the contact rate between the alkaline slurry and the sulfur-containing tail gas by pressurizing, solves the problem that the sulfur-containing tail gas cannot fully contact with the alkaline slurry, and improves the desulfurization efficiency.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] An exhaust gas treatment device for an aluminum casting process comprises a desulfurization tower body, a flue gas outlet, a flue gas inlet, a cyclone, a spray layer, a demister, a manhole door, a sewage outlet, a bottom fixing seat, a four-stage sedimentation tank, a circulating water pump, a reagent pipeline and a slurry pipeline; the inner cavity of the desulfurization tower body is provided with a cyclone, two spray layers and a demister from bottom to top in sequence; the spray layer is provided directly above the cyclone, the spacing height between the spray layer and the cyclone is determined by the spray angle of the spray head, the spray layer is provided with a spray main pipe and a spray branch pipe, the main spray pipe is fixed on a tower outer support pipe and a tower inner support support plate, a plurality of spray branch pipes are arranged on the main spray pipe, the spray port is arranged downward on the main spray pipe and the spray branch pipe, and the spacing height of the spray layers is determined by the total number of spray layers and the spray angle of the spray head;

[0007] The top of the desulfurization tower body is provided with a flue gas outlet, the bottom of the desulfurization tower body is provided with a flue gas inlet and a manhole door, and a sewage outlet is provided on the side wall of the bottom of the desulfurization tower body;

[0008] The four-stage sedimentation tank is connected to the desulfurization tower body through a sewage outlet, and the spray liquid containing dust flows into the four-stage sedimentation tank through the sewage outlet. The reagent pipeline is installed above the four-stage sedimentation tank, and a precipitant is added into the four-stage sedimentation tank. After sufficient stirring and precipitation, a clear liquid and a precipitate are obtained. The clear liquid is recycled through a circulating water pump installed just above the four-stage sedimentation tank, and enters the desulfurization tower body again through a slurry pipeline for desulfurization.

[0009] Furthermore, the contact mode between the alkaline solution sprayed by the spray layer and the flue gas is countercurrent contact.

[0010] Furthermore, the spacing height of the spray layer is 1-4m, and the spacing height between the spray layer and the cyclone is 1-1.5m.

[0011] Furthermore, the spray main pipe and the spray branch pipe are arranged vertically and crosswise, the spray heads are arranged evenly in a circular manner, the number of the spray heads is not less than the square of the number of the spray branch pipes, the spray heads are spiral spray heads, the spray direction of the spray heads is vertically downward, and the spray angle is 60°-180°.

[0012] The demister includes a primary demister and a secondary demister. The secondary demister is located above the primary demister. The blade spacing on the secondary demister is 1-5 mm smaller than the blade spacing of the primary demister. The blade spacing of the primary demister is less than or equal to 30 mm. The blade heights of the primary demister and the secondary demister are not less than 170 mm.

[0013] The first-stage demister and the second-stage demister both include rectangular tubes, blades and fixed U-shaped grooves. The rectangular tubes and fixed U-shaped grooves are fixed on the desulfurization tower body. The fixed U-shaped grooves clamp the fixed blades through "U"-shaped grooves. The blades are arranged in parallel.

[0014] The angle of the cyclone blades is 30°-50°.

[0015] The device also includes a desulfurization inspection hole, an inspection port and an inspection platform. Two inspection holes and inspection platforms are respectively arranged inside and outside the desulfurization tower body between the two spray layers and between the two-stage demisters; an inspection platform and an inspection port are arranged at the upper end of the desulfurization tower body.

[0016] The technical concept of the utility model is as follows: the exhaust gas generated after the combustion of the smelting furnace controls the frequency of the main exhaust fan through the furnace pressure sensor, and the exhaust gas is forced to be discharged to the main exhaust pipe, and the exhaust fan is pressurized to send the flue gas to the bottom of the wet spray tower, and first passes through the cyclone to separate the large particles in the flue gas, while ensuring that the flue gas passing through has a certain flow rate; then passes through the double-stage spray layer, the spray layer is provided with 16 sets of rotary atomizing nozzles, and the spray heads are evenly distributed on the spray layer in a circular manner. After the spray liquid is pressurized, a fog-like water curtain with no dead angle from top to bottom is formed inside the tower, which greatly increases the contact area and rate between the alkaline slurry and the flue gas, and improves the desulfurization effect. The spacing height between the spray layers is 1-4m, and the spacing height between the spray layer and the cyclone is 1-1.5m; then passes through the first-stage demister and the second-stage demister to remove small droplets containing harmful substances generated by the reaction in the tail gas, and then reaches the emission standard.

[0017] The beneficial effects of the utility model are mainly manifested in: increasing the contact area and rate between the alkaline slurry and the flue gas, improving the desulfurization effect, and obtaining gas that meets the emission standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of an exhaust gas treatment device for an aluminum casting process;

[0019] Figure 2 Schematic diagram of the first-stage demister, (a) is the overall diagram, (b) is the schematic diagram of the blades and the fixed U-shaped groove;

[0020] Figure 3 is a schematic diagram of the spray layer;

[0021] Figure 4 is a schematic diagram of a cyclone, wherein (a) is a cross-sectional view and (b) is a top view;

[0022] Figure 5 is a schematic diagram of a bottom fixing seat, wherein (a) is a cross-sectional view and (b) is a top view;

[0023] Markings in the attached figure: 1- flue gas outlet, 2- detection port, 3- inspection hole, 4- maintenance platform, 5- secondary demister, 6- primary demister, 61- rectangular tube, 62- blade, 63- fixed U-shaped groove, 7- desulfurization tower body, 8- spray layer, 81- supporting plate inside the tower, 82- spray head, 83- spray branch pipe, 84- spray main pipe, 85- supporting pipe outside the tower, 9- cyclone, 91- blade, 10- escalator, 11- flue gas inlet, 12- drain outlet, 13- anchor bolt, 14- bottom fixing seat, 15- manhole door, 16- sewage outlet, 17- fourth-stage sedimentation tank, 18- reagent pipeline, 19- circulating water pump, 20- slurry pipeline. DETAILED DESCRIPTION

[0024] The utility model is further described below in conjunction with the accompanying drawings.

[0025] Reference Figure 1 to Figure 5 A tail gas treatment device for an aluminum casting process includes a desulfurization tower body 7, a flue gas outlet 1, a flue gas inlet 11, a cyclone 9, a spray layer 8, a demister (including a primary demister 6 and a secondary demister 5), a manhole door 15, a sewage outlet 16, an inspection hole 3, a detection port 2, a maintenance platform 4, a bottom fixing seat 14, a four-stage sedimentation tank 17, a circulating water pump 19, a reagent pipeline 18 and a slurry pipeline 20.

[0026] The inner cavity of the desulfurization tower body 7 is provided with a cyclone 9, two spray layers 8, and a demister (including a primary demister 6 and a secondary demister 5) in sequence from bottom to top; the spray layer 8 is arranged directly above the cyclone 9, and the spacing height between the spray layer 8 and the cyclone 9 is determined by the spray angle of the spray head 82. There are a spray main pipe 84 and a spray branch pipe 83 on the spray layer 8, and the main spray pipe 84 is fixed on the outer support pipe 85 of the tower and the support plate 81 inside the tower. A plurality of spray branch pipes 83 are arranged on the main spray pipe 84, and the spray head 82 is arranged downward on the main spray pipe 84 and the spray branch pipe 83 inside the tower, and the spray layer spacing height is determined by the total number of spray layers and the spray angle of the spray head.

[0027] A flue gas outlet 1 is provided at the top of the desulfurization tower body 7, a flue gas inlet 11 and a manhole door 15 are provided at the bottom, and two inspection holes 3 and an inspection platform 4 are respectively provided inside and outside the desulfurization tower body between the two spray layers and between the first and second level demisters; an inspection platform and two inspection ports are provided at the upper end of the desulfurization tower body; a sewage outlet 16 is provided on the side wall at the bottom of the desulfurization tower body.

[0028] The four-stage sedimentation tank 17 is connected to the desulfurization tower body through the sewage outlet 16, and the spray liquid containing dust flows into the four-stage sedimentation tank 17 through the sewage outlet 16. The reagent pipeline 18 is installed above the four-stage sedimentation tank 17. The precipitant is added into the four-stage sedimentation tank 17. After sufficient stirring and precipitation, clear liquid and precipitate are obtained. The clear liquid is recycled through the circulating water pump 19 installed just above the four-stage sedimentation tank, and enters the desulfurization tower body again through the slurry pipeline 20 for desulfurization.

[0029] The contact mode between the alkaline solution sprayed by the spray layer 8 and the flue gas adopts a countercurrent contact mode, which can greatly increase the contact area between the tail gas and the alkaline slurry, thereby achieving a better reaction and improving the desulfurization efficiency.

[0030] The spacing height of the spray layer 8 is 1-4m, and the spacing height between the spray layer 8 and the cyclone 9 is 1-1.5m, which ensures the exhaust gas flow rate when the exhaust gas contacts the alkaline slurry while also being able to well cover the internal area of ​​the desulfurization tower.

[0031] The spray main pipe 84 and the spray branch pipe 83 are arranged vertically and crosswise, the spray heads 82 are arranged evenly in a circular manner, the number of the spray heads 82 is not less than the square of the number of the spray branch pipes, the spray heads 82 are spiral spray heads, the spray direction of the spray heads 82 is vertically downward, the spray angle is 60°-180°, and a fog-like water curtain with no dead angles from top to bottom can be formed inside the tower.

[0032] The first-stage demister 6 and the second-stage demister 5 both include a rectangular tube 61, blades 62 and a fixed U-shaped groove 63. The rectangular tube 61 and the fixed U-shaped groove 63 are fixed on the desulfurization tower body 7. The fixed U-shaped groove 63 clamps the fixed blades 62 through a "U"-shaped groove. The blades 62 are arranged in parallel.

[0033] The blade spacing on the secondary demister 5 is 1-5 mm smaller than that of the primary demister 5 , the blade spacing of the primary demister 5 is less than or equal to 30 mm, and the blade heights of the primary demister 5 and the secondary demister 5 are not less than 170 mm.

[0034] The blade angle of the cyclone 9 is 30°-50°, which ensures the separation of large particles in the tail gas while ensuring a good tail gas flow rate.

[0035] The working process of this embodiment is as follows: the exhaust gas generated after the combustion of the smelting furnace controls the frequency of the main exhaust fan through the furnace pressure sensor, and the exhaust gas is forced to be discharged to the main exhaust pipe, and the exhaust fan is pressurized to send the flue gas to the bottom of the wet spray tower, and first passes through the cyclone to separate the large particles in the flue gas, while ensuring that the flue gas passing through has a certain flow rate; then passes through the double-stage spray layer, and the spray layer is provided with 16 sets of rotating atomizing nozzles, and the spray heads are evenly distributed on the spray layer in a circular manner. After the spray liquid is pressurized, a mist-like water is formed from top to bottom inside the tower without dead corners. The curtain greatly increases the contact area and rate between the alkaline slurry and the flue gas, and improves the desulfurization effect. The spacing height between the spray layers is 1-4m, and the spacing height between the spray layer and the cyclone is 1-1.5m; then it passes through the first-level demister and the second-level demister to remove small droplets containing harmful substances produced by the reaction in the exhaust gas, and then reaches the emission standard. The exhaust gas treatment device for the aluminum casting process provided by the present invention can greatly increase the contact area and rate between the alkaline slurry and the flue gas, improve the desulfurization effect, and obtain gas that meets the emission standards.

[0036] The contents described in the embodiments of this specification are merely enumerations of implementation forms of the utility model concept and are for illustrative purposes only. The protection scope of the utility model should not be considered to be limited to the specific forms described in this embodiment, and the protection scope of the utility model also extends to equivalent technical means that ordinary technicians in this field can think of based on the concept of the utility model.

Claims

1. A tail gas treatment device for aluminum casting process, characterized in that: The device comprises a desulfurization tower body, a flue gas outlet, a flue gas inlet, a cyclone, a spray layer, a demister, a manhole door, a sewage outlet, a bottom fixing seat, a four-stage sedimentation tank, a circulating water pump, a reagent pipeline and a slurry pipeline; the inner cavity of the desulfurization tower body is provided with a cyclone, two layers of spray layers and a demister from bottom to top in sequence; the spray layer is provided directly above the cyclone, the spacing height between the spray layer and the cyclone is determined by the spray angle of the spray head, the spray layer is provided with a spray main pipe and a spray branch pipe, the spray main pipe is fixed on the supporting pipe outside the tower and the supporting support plate inside the tower, a plurality of spray branch pipes are arranged on the spray main pipe, the spray port is arranged downward on the spray main pipe and the spray branch pipe inside the tower, and the spacing height of the spray layers is determined by the total number of spray layers and the spray angle of the spray head; The top of the desulfurization tower body is provided with a flue gas outlet, the bottom of the desulfurization tower body is provided with a flue gas inlet and a manhole door, and a sewage outlet is provided on the side wall of the bottom of the desulfurization tower body; The four-stage sedimentation tank is connected to the desulfurization tower body through a sewage outlet, and the spray liquid containing dust flows into the four-stage sedimentation tank through the sewage outlet. The reagent pipeline is installed above the four-stage sedimentation tank, and a precipitant is added into the four-stage sedimentation tank. After sufficient stirring and precipitation, a clear liquid and a precipitate are obtained. The clear liquid is recycled through a circulating water pump installed just above the four-stage sedimentation tank, and enters the desulfurization tower body again through a slurry pipeline for desulfurization.

2. The tail gas treatment device for aluminum casting process according to claim 1, characterized in that: The contact mode between the alkaline solution sprayed by the spray layer and the flue gas adopts countercurrent contact mode.

3. A tail gas treatment device for aluminum casting process according to claim 1 or 2, characterized in that: The spacing height of the spray layer is 1-4m, and the spacing height between the spray layer and the cyclone is 1-1.5m.

4. A tail gas treatment device for aluminum casting process according to claim 1 or 2, characterized in that: The spray main pipe and the spray branch pipe are arranged vertically and crosswise, the spray heads are arranged evenly in a circular manner, the number of the spray heads is not less than the square of the number of the spray branch pipes, the spray heads are spiral spray heads, the spray direction of the spray heads is vertically downward, and the spray angle is 60°-180°.

5. The tail gas treatment device for aluminum casting process according to claim 1 or 2, characterized in that: The demister includes a primary demister and a secondary demister. The secondary demister is located above the primary demister. The blade spacing on the secondary demister is 1-5 mm smaller than the blade spacing of the primary demister. The blade spacing of the primary demister is less than or equal to 30 mm. The blade heights of the primary demister and the secondary demister are not less than 170 mm.

6. The tail gas treatment device for aluminum casting process according to claim 5, characterized in that: The first-stage demister and the second-stage demister both include rectangular tubes, blades and fixed U-shaped grooves. The rectangular tubes and fixed U-shaped grooves are fixed on the desulfurization tower body. The fixed U-shaped grooves clamp the fixed blades through "U"-shaped grooves, and the blades are arranged in parallel.

7. The tail gas treatment device for aluminum casting process according to claim 1 or 2, characterized in that: The angle of the cyclone blades is 30°-50°.

8. The tail gas treatment device for aluminum casting process according to claim 1 or 2, characterized in that: The device also includes a desulfurization inspection hole, an inspection port and an inspection platform. Two inspection holes and inspection platforms are respectively arranged inside and outside the desulfurization tower body between the two spray layers and between the two-stage demisters; an inspection platform and an inspection port are arranged at the upper end of the desulfurization tower body.

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