Demister

Abstract

The utility model provides a demister. The demister comprises a rotational flow layer, a baffle plate layer and a silk screen layer which are arranged layer by layer in the advancing direction of flue gas, the baffle plate layer comprises a fixed ferrule and a plurality of layers of baffle plates arranged in the fixed ferrule; each baffle plate comprises a baffle plate body and a first heat exchange pipe arranged at the bending corner of the baffle plate body, and each first heat exchange pipe comprises a first heat exchange straight pipe perpendicular to the flue gas advancing direction and a first heat exchange bent pipe used for communicating every two adjacent first heat exchange straight pipes; and a second heat exchange tube is embedded in the silk screen layer. According to the demister disclosed by the invention, through the arrangement of the devices, the heat in the flue gas is recovered while the demisting effect is realized, and the defect that energy is wasted due to the fact that the heat in the flue gas is difficult to recover when a traditional demister is used for demisting is overcome.

Description

Technical Field

[0001] The present application relates to the technical field of demisting in desulfurization towers, and in particular to a demister. Background Art

[0002] Sulfur oxides (SO x ), nitrogen oxides (NO x ) is one of the main air pollutants, which not only pollutes the environment, but also seriously threatens people's health and life. The main sources of these pollutants are the combustion of mineral fuel coal and the flue gas produced during the smelting process.

[0003] In order to reduce the content of sulfur oxides in flue gas, countries around the world are using flue gas desulfurization technology. Flue gas desulfurization technology can be divided into three types of processes: wet process, dry process and semi-dry process according to the difference in desulfurization method and the form of desulfurized products. Among them, wet desulfurization technology has become the most commonly used technology around the world due to its high desulfurization efficiency, reliable operation and low investment and operation costs. In the wet desulfurization process, the desulfurization efficiency can only be maximized when the flue gas temperature is cooled to below the dew point temperature of water. However, this makes the flue gas almost wet saturated after the wet desulfurization process. After the flue gas is discharged through the chimney, it will encounter the cold air outside, which will cause "chimney rain" and "white smoke" phenomena. In the desulfurization system, demisters (such as baffle demisters, wet electrostatic demisters and cyclone plate demisters, etc.) are required. Although this type of demister can alleviate the white smoke phenomenon to a certain extent, it mainly condenses the fine droplets of water mist into larger droplets through physical interception, centrifugation, etc. to achieve the purpose of demisting. However, this method cannot recover the heat in the flue gas and will cause some heat loss. Utility Model Content

[0004] The present application provides a demister to solve the above technical problems.

[0005] The present application provides a demister, comprising a swirl layer, a baffle layer and a wire mesh layer arranged layer by layer along the direction of smoke travel;

[0006] The baffle layer includes a fixed collar and a multi-layer baffle arranged in the fixed collar;

[0007] The baffle includes a baffle body and a first heat exchange tube arranged at a bent corner in the baffle body, wherein the first heat exchange tube includes a first heat exchange straight tube perpendicular to the direction of smoke travel and a first heat exchange bent tube for connecting two adjacent first heat exchange straight tubes;

[0008] A second heat exchange tube is buried in the wire mesh layer.

[0009] Optionally, the second heat exchange tube includes a second heat exchange straight tube parallel to the direction of smoke travel and a second heat exchange bent tube for connecting two adjacent second heat exchange straight tubes end to end.

[0010] Optionally, a spray layer is provided on top of the wire mesh layer;

[0011] The spray layer includes a liquid supply component composed of two sections of liquid supply pipes, one end of which is open and the other end is closed;

[0012] The two sections of the liquid supply pipe are connected through a plurality of liquid guide pipes, and a plurality of spray heads are arranged in an array on the lower surface of the liquid guide pipes.

[0013] Optionally, a plurality of mutually parallel first direction grooves and a plurality of mutually parallel second direction grooves are arranged in an array on the surface of the baffle body; the first direction grooves and the second direction grooves are arranged crosswise, and the angle between the two is 30 to 90°.

[0014] Optionally, a plurality of conical protrusions are arranged on the surface of the baffle body, and the conical protrusions are arranged perpendicular to the surface of the baffle body.

[0015] Optionally, a plurality of fins are arranged in an array on the periphery of the first heat exchange straight tube, and the fins are perpendicular to the central axis of the first heat exchange straight tube.

[0016] Optionally, a cover plate is provided at one end of the plurality of fins along the direction of smoke travel, and a width of the cover plate is 0.5 to 1 times of the extended length of the fins.

[0017] The demister provided in the present application strengthens the demistering of the flue gas by arranging the swirl layer, the baffle layer and the wire mesh layer layer by layer along the direction of the flue gas travel, and at the same time, arranges the first heat exchange tube at the bending corner of the baffle body of the baffle layer, and arranges the second heat exchange tube in the wire mesh layer to recover the heat in the flue gas by heat exchange. Through the arrangement of the above-mentioned device, while achieving the demisting effect, the heat in the flue gas is recovered to reduce energy waste, thus overcoming the disadvantage that the traditional demister is difficult to recover the heat in the flue gas during demisting, resulting in energy waste. In addition, the first heat exchange tube and the second heat exchange tube are arranged, and while recovering the heat in the flue gas by heat exchange, the temperature of the flue gas can be reduced so that the moisture in the flue gas can be condensed, which can further improve the demisting efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A schematic diagram of the structure of a demister provided in one embodiment of the present application;

[0020] Figure 2A schematic diagram of the structure of a baffle layer provided in one embodiment of the present application;

[0021] Figure 3 A schematic diagram of the structure of a baffle provided in one embodiment of the present application;

[0022] Figure 4 A schematic diagram of the structure of a second heat exchange tube provided in one embodiment of the present application;

[0023] Figure 5 A schematic diagram of the structure of a demister provided in another embodiment of the present application;

[0024] Figure 6 A schematic diagram of the structure of a spray layer provided in one embodiment of the present application;

[0025] Figure 7 A schematic diagram of a partial structure of the baffle body surface provided in one embodiment of the present application;

[0026] Figure 8 A schematic diagram of the side structure of a baffle body provided in another embodiment of the present application;

[0027] Fig. 9 A schematic diagram of the structure of a first heat exchange straight tube provided in one embodiment of the present application.

[0028] Description of reference numerals:

[0029] 1. Swirl layer; 2. Baffle layer; 3. Wire mesh layer; 4. Spray layer; 21. Fixed collar; 22. Baffle; 23. First direction groove; 24. Second direction groove; 25. Conical protrusion; 31. Second heat exchange tube; 41. Liquid supply tube; 42. Liquid guide tube; 43. Spray head; 221. Baffle body; 222. First heat exchange tube; 223. Fin; 311. Second heat exchange straight tube; 312. Second heat exchange elbow; 2221. First heat exchange straight tube; 2222. First heat exchange elbow; 2231. Cover plate. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0031] like Figure 1 to Figure 3 As shown, the present application provides a demister, comprising a swirl layer 1, a baffle layer 2 and a wire mesh layer 3 arranged layer by layer along the direction of smoke travel;

[0032] The baffle layer 2 includes a fixed collar 21 and a multi-layer baffle 22 arranged in the fixed collar 21;

[0033] The baffle 22 includes a baffle body 221 and a first heat exchange tube 222 disposed at a bent corner of the baffle body 221. The first heat exchange tube 222 includes a first heat exchange straight tube 2221 perpendicular to the direction of smoke travel and a first heat exchange elbow 2222 for connecting two adjacent first heat exchange straight tubes 2221.

[0034] A second heat exchange tube 31 is buried in the wire mesh layer 3 .

[0035] In the present application, the cyclone layer 1 includes a cyclone demister (also called a cyclone plate demister). The cyclone layer 1 is set in the first layer that contacts the flue gas because the flue gas velocity is relatively large at this time. The cyclone demister entering the cyclone layer can obtain a higher centrifugal speed, which is conducive to the separation of water mist droplets in the flue gas. The cyclone plate demister is a prior art and will not be described in detail here. Its general structure is composed of cyclone blades, baffle rings, cylindrical hoods and external cylinders. Multiple blades with a certain inclination angle to the horizontal plane are distributed around the central blind plate. These blades are bonded to the central blind plate, and the outer ends of the blades are welded to the cylindrical hood. When in use, when the airflow carries droplets into the cyclone plate, the fluid is subjected to centrifugal force to rotate, and the droplets are thrown to the wall and removed.

[0036] When the demister provided in the present application is in use, the smoke direction is taken as the vertical direction and moves from bottom to top.

[0037] The flue gas moves from bottom to top and first enters the cyclone demister of the cyclone layer 1. When the flue gas carries droplets into the cyclone plate, the flue gas rotates due to the centrifugal force, and the droplets are thrown to the wall and removed. After the droplets are removed from the cyclone layer 1, the flue gas continues to move upward and enters the baffle layer 2 for further defog.

[0038] When the upward flue gas enters the curved channel formed by the space between the baffles 22 of the baffle layer 2, after the flue gas carries droplets into the baffle flow field, its movement direction changes continuously due to the tortuosity of the internal space, and the droplets inertially impact the windward surface of the baffle body 221, accumulating into a liquid film, and finally slowly flow down due to the action of gravity to achieve gas-liquid two-phase separation. At the same time, the first heat exchange tube 222 at the bent corner of the baffle body 221 contacts the droplets for heat exchange, which reduces the flue gas temperature and also causes the gaseous water in the flue gas to condense due to cooling, thereby reducing the water content in the flue gas.

[0039] After the flue gas is defogged by the baffle layer 2, it enters the wire mesh layer 3, which is composed of multiple layers of woven wire mesh. A second heat exchange tube 31 is buried in the wire mesh layer 3. While the wire mesh is used to intercept the water mist in the flue gas, the second heat exchange tube 31 is used to further reduce the flue gas temperature, thereby further reducing the water content in the flue gas.

[0040] The demister provided in the present application strengthens the demistering of the flue gas by arranging the swirl layer 1, the baffle layer 2 and the wire mesh layer 3 layer by layer along the direction of the flue gas travel, and at the same time, arranges the first heat exchange tube 222 at the bending corner of the baffle body 221 of the baffle layer 2, and arranges the second heat exchange tube 31 in the wire mesh layer, so as to recover the heat in the flue gas by heat exchange. Through the arrangement of the above-mentioned device, the heat in the flue gas is recovered while achieving the demisting effect, and the energy waste is reduced, thus overcoming the disadvantage that the traditional demister is difficult to recover the heat in the flue gas during demisting, resulting in energy waste. In addition, the first heat exchange tube 222 and the second heat exchange tube 31 are arranged, and while recovering the heat in the flue gas by heat exchange, the temperature of the flue gas can be reduced so that the moisture in the flue gas can be condensed, which can further improve the demisting efficiency.

[0041] like Figure 4 As shown, optionally, the second heat exchange tube 31 includes a second heat exchange straight tube 311 parallel to the direction of smoke travel and a second heat exchange bent tube 312 for connecting two adjacent second heat exchange straight tubes 311 end to end.

[0042] In the present application, the second heat exchange tube 31 can further reduce the temperature of the flue gas, so that the water in the flue gas condenses and is intercepted and removed by the wire mesh. The second heat exchange tube 31 is folded in multiple layers. In practice, the second heat exchange straight tube 311 is parallel to the direction of the flue gas, which can effectively reduce the flue gas pressure drop; if the second heat exchange straight tube 311 is perpendicular to the direction of the flue gas, although it is beneficial to the heat exchange of the flue gas, this setting greatly reduces the flue gas flow rate, and it is set in the wire mesh layer 3, so the pressure drop in the tower is large when in use, and gas blocking is prone to occur, and the heat that can be recovered in the flue gas after cooling by the baffle layer 2 will be reduced. Therefore, considering comprehensively, it is appropriate to set the second heat exchange straight tube 311 to be parallel to the direction of the flue gas.

[0043] like Figure 5 and Figure 6 As shown, optionally, a spray layer 4 is provided on the top of the wire mesh layer 3;

[0044] The spray layer 4 includes a liquid supply component composed of two sections of liquid supply pipes 41, one end of the liquid supply pipe 41 is open and the other end is closed;

[0045] The two sections of the liquid supply pipe 41 are connected through a plurality of liquid guide pipes 42 , and a plurality of spray heads 43 are arranged in an array on the lower surface of the liquid guide pipe 42 .

[0046] In the present application, the shape of the liquid supply component matches the internal shape of the equipment using the demister, such as a desulfurization tower. For example, if the cross-section of the internal shape of the desulfurization tower is circular, the liquid supply component is composed of two semicircular sections of liquid supply pipes 41. When setting, the two sections of the liquid supply pipe 41 can be spliced ​​with the open end of one section of the liquid supply pipe 41 close to the closed end of the other section of the liquid supply pipe 41, or the open ends of the two sections of the liquid supply pipe 41 can be spliced ​​close to each other; the specific splicing method can be selected as needed.

[0047] The two sections of the liquid supply pipe 41 are connected by multiple liquid guide pipes 42 equipped with spray heads 43, so that water can be supplied from both ends of the liquid guide pipe 42 through the two sections of the liquid supply pipe 41 at the same time. This method can not only stabilize the water supply pressure, but also can still spray when one section of the liquid supply pipe 41 is blocked, thereby improving the fault tolerance rate.

[0048] like Figure 7 As shown, optionally, a plurality of mutually parallel first direction grooves 23 and a plurality of mutually parallel second direction grooves 24 are arrayed on the surface of the baffle body 221; the first direction grooves 23 and the second direction grooves 24 are cross-arranged, and the angle between the two is 30 to 90°.

[0049] In the present application, intersecting first direction grooves 23 and second direction grooves 24 are arranged on the surface of the baffle body 221, which can increase the specific surface area of ​​the plate surface, help form a water film to capture droplets with smaller particle sizes and enable rapid drainage, and can effectively reduce the phenomenon of secondary water carrying caused by airflow tearing the liquid film gathered on the plate surface. When the thickness of the baffle body 221 is greater than 10 mm, the depth of the above groove is, for example, 0.8 to 1 mm. In another alternative mode, when the thickness of the baffle body 221 is less than 10 mm, the above groove can be arranged as a protrusion of corresponding length, and the height of the protrusion can be 1 to 1.5 mm.

[0050] like Figure 8 As shown, optionally, a plurality of conical protrusions 25 are provided on the surface of the baffle body 221 , and the conical protrusions 25 are arranged perpendicular to the surface of the baffle body 221 .

[0051] In the present application, the conical protrusions 25 are conducive to the water mist to gather on its surface and condense into large droplets to remove the water mist. The conical protrusions 25 are in the shape of a cone or a pyramid, and the cone angle of the top ranges from 60 to 120 degrees.

[0052] like Fig. 9 As shown, optionally, a plurality of fins 223 are arranged in an array on the periphery of the first heat exchange straight tube 2221 , and the fins 223 are perpendicular to the central axis of the first heat exchange straight tube 2221 .

[0053] In the present application, the fin 223 is perpendicular to the central axis of the first heat exchange straight tube 2221, that is, parallel to the airflow direction, which can reduce the pressure drop to a certain extent. Moreover, the arrangement of the fin 223 can effectively improve the heat exchange efficiency.

[0054] like Fig. 9 As shown, optionally, a cover plate 2231 is provided at one end of the plurality of fins 223 along the direction of smoke travel, and the width of the cover plate 2231 is 0.5 to 1 times the extended length of the fin 223 .

[0055] When the cover plate 2231 in the present application is set, it extends in the direction away from the first heat exchange straight tube 2221 and in the direction of the first heat exchange straight tube 2221. In this way, when the width of the cover plate 2231 is less than the extended length of the fin 223, a space will be left near the first heat exchange straight tube 2221, so that the flow direction of the airflow flowing through the space is changed, thereby increasing the collision with the mainstream smoke, so that the droplets in the smoke at this part can merge with each other, which is convenient for separation. The cover plate 2231 as a whole can play a role in blocking part of the smoke. After the part of the smoke is blocked by the cover plate 2231, this part of the smoke will be opposite to the direction of the mainstream smoke. When the two meet, the droplets in the returning smoke meet the droplets in the forward smoke and merge into larger droplets, so as to facilitate the removal of water mist in the smoke. At the same time, the cover plate 2231 can prolong the residence time of the smoke in the baffle layer 2 to a certain extent, which is convenient for the precipitation of the droplets in the smoke.

[0056] A demister, the working process of which is as follows:

[0057] When in use, take the smoke direction as the vertical direction and move from bottom to top as an example.

[0058] The flue gas moves from bottom to top and first enters the cyclone demister of the cyclone layer 1. When the flue gas carries droplets into the cyclone plate, the flue gas rotates due to the centrifugal force, and the droplets are thrown to the wall and removed. After the droplets are removed from the cyclone layer 1, the flue gas continues to move upward and enters the baffle layer 2 for further defog.

[0059] When the upward flue gas enters the curved channel formed by the space between the baffles 22 of the baffle layer 2, after the flue gas carries droplets into the baffle flow field, its movement direction changes continuously due to the tortuosity of the internal space, and the droplets inertialy impact on the windward surface of the baffle body 221, accumulating into a liquid film, and finally slowly flow down due to the action of gravity to achieve gas-liquid two-phase separation. At the same time, the first heat exchange tube 222 at the bent corner of the baffle body 221 contacts the droplets for heat exchange, which reduces the flue gas temperature and also causes the gaseous water in the flue gas to condense due to cooling, and the fins 223 arranged on the periphery of the first heat exchange straight tube 2221 in the first heat exchange tube 222 can enhance heat exchange, further reduce the temperature in the flue gas, and thus reduce the water content in the flue gas. In addition, a cover plate 2231 is arranged at one end of the fin 223 along the direction of smoke travel (in this case, the upper end of the fin 223). The setting of the cover plate 2231 can block part of the smoke. After the part of the smoke is blocked by the cover plate 2231, this part of the smoke will be in the opposite direction of the mainstream smoke. When the two meet, the droplets in the returning smoke meet the droplets in the forward smoke and merge into larger droplets, so as to facilitate the removal of water mist in the smoke. At the same time, the setting of the cover plate can prolong the residence time of the smoke in the baffle layer 2 to a certain extent, so as to facilitate the sedimentation of the droplets in the smoke. Moreover, the conical protrusions 25 on the surface of the baffle body 221 are also conducive to the water mist to gather and condense into large droplets on its surface to remove the water mist. In addition, the first direction grooves 23 and the second direction grooves 24 arranged in an intersecting manner on the surface of the baffle body 221 can increase the specific surface area of ​​the plate surface, help the formation of water film to capture droplets with smaller particle sizes and enable rapid drainage, which can effectively reduce the phenomenon of secondary water entrainment caused by airflow tearing the liquid film gathered on the plate surface.

[0060] After the flue gas is defogged by the baffle layer 2, it enters the wire mesh layer 3, which is composed of multiple layers of woven wire mesh. The second heat exchange tube 31 is buried in the wire mesh layer 3. While the wire mesh is used to intercept the water mist in the flue gas, the second heat exchange tube 31 is used to further reduce the flue gas temperature, thereby reducing the water content in the flue gas.

[0061] After the demister has been used for a period of time, dirt such as smoke will adhere to the components in the demister, especially the wire mesh layer 3. These dirt will clog the mesh holes of the wire mesh, causing the pressure drop of the flue gas to increase, thus affecting the demisting efficiency. At this time, water (or cleaning liquid) can be supplied to the liquid supply pipes 41 at both ends of the spray layer 4 at the same time, and the water can be drained to the spray head 43 through the liquid guide pipe 42 to flush the wire mesh layer 3.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A demister, characterized in that: It comprises a swirl layer (1), a baffle layer (2) and a wire mesh layer (3) which are arranged layer by layer along the direction of smoke travel; The baffle layer (2) comprises a fixed ring (21) and a multi-layer baffle (22) arranged in the fixed ring (21); The baffle (22) comprises a baffle body (221) and a first heat exchange tube (222) arranged at a bent corner in the baffle body (221), wherein the first heat exchange tube (222) comprises a first heat exchange straight tube (2221) perpendicular to the direction of smoke travel and a first heat exchange bent tube (2222) for connecting two adjacent first heat exchange straight tubes (2221); A second heat exchange tube (31) is buried in the wire mesh layer (3).

2. The demister according to claim 1, characterized in that: The second heat exchange tube (31) comprises a second heat exchange straight tube (311) parallel to the direction of smoke travel and a second heat exchange bent tube (312) for connecting two adjacent second heat exchange straight tubes (311) end to end.

3. The demister according to claim 1, characterized in that: A spray layer (4) is provided on the top of the wire mesh layer (3); The spray layer (4) comprises a liquid supply component composed of two sections of liquid supply pipes (41), one end of the liquid supply pipe (41) is open and the other end is closed; The two sections of the liquid supply pipe (41) are connected via a plurality of liquid guide pipes (42), and a plurality of spray heads (43) are arranged in an array on the lower surface of the liquid guide pipe (42).

4. The demister according to claim 1, characterized in that: The baffle body (221) is provided with a plurality of mutually parallel first direction grooves (23) and a plurality of mutually parallel second direction grooves (24) in an array on its surface; the first direction grooves (23) and the second direction grooves (24) are arranged crosswise, and the angle between the first direction grooves (23) and the second direction grooves (24) is 30 to 90 degrees.

5. The demister according to any one of claims 1 to 4, characterized in that: A plurality of conical protrusions (25) are arranged on the surface of the baffle body (221), and the conical protrusions (25) are arranged perpendicular to the surface of the baffle body (221).

6. The demister according to claim 1, characterized in that: A plurality of fins (223) are arranged in an array on the periphery of the first heat exchange straight tube (2221), and the fins (223) are perpendicular to the central axis of the first heat exchange straight tube (2221).

7. The demister according to claim 6, characterized in that: A cover plate (2231) is provided at one end of the plurality of fins (223) along the direction of smoke travel, and the width of the cover plate (2231) is 0.5 to 1 times the extended length of the fin (223).

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