Gas Scrubber for Removing Particles from an Exhaust Gas and an Exhaust Gas Disposal System with a Gas Scrubber

Abstract

A gas scrubber and a waste gas treatment system with a gas scrubber for removing particles from a waste gas has a housing with a waste gas inlet and a waste gas outlet. A substantially circular plate member defining an axis of rotation is rotatably arranged in the housing. Waste gas fed into the housing via the waste gas inlet is directed toward approximately the center of the circular plate member. An outlet nozzle sprays a liquid, especially a cleaning liquid or a scrubbing liquid, onto the circular plate member, in order to obtain a mixture of waste gas and liquid in front of the plate member. A combination of inner and outer rotor arrays, and inner and outer stator arrays are arranged alternatingly and concentrically relative to each other, and separated from the circular plate member, and rotate about the axis of rotation. A rotary atomizer for atomizing the mixture of waste gas and liquid may be arranged on the circular plate member. Particles from the waste gas stream are transferred into the liquid.

Claims

1. A gas scrubber (1) for removing particles from a waste gas, comprising: a housing (10) with a waste gas inlet (2) and a waste gas outlet (3); a substantially circular plate member (8) defining a center (15) that is arranged in the housing (10) and configured to rotate about its own axis (11) and configured so that waste gas fed into the housing via the waste gas inlet (2) is directed toward the center (15) of the plate member (8); an outlet nozzle (12) configured to spray a liquid (13) onto the circular plate member (8) in order to obtain a mixture of waste gas and liquid (13) in front of the circular plate member (8); at least one inner rotor array (4) and one outer rotor array (5) situated at a distance from the inner rotor array (4), both of which are rotatable around the axis (11); at least one inner stator array (6) and one outer stator array (7) arranged at a distance from inner stator array (6), with the rotor arrays (4, 5) and the stator arrays (6, 7) arranged alternatingly and concentrically relative to each other, and configured to create turbulence so that particles from the waste gas stream can be transferred into the liquid (13); and a rotary atomizer (20) for atomizing the liquid (13) arranged on the circular plate member (8).

2. The gas scrubber (1) according to claim 1, wherein the rotary atomizer (20) is configured as a disk with an atomization edge (21).

3. The gas scrubber (1) according to claim 2, wherein the rotary atomizer (20) is shaped so as to be concave towards its outer edge.

4. The gas scrubber (1) according to claim 2, wherein the rotary atomizer (2) defines a center (32), and said center (32) has a convex elevation (33) that reaches or exceeds the height of the atomizing edge (21).

5. The gas scrubber (1) according to claim 1, wherein the inner and outer rotor arrays (4, 5) are driven by a shared shaft.

6. The gas scrubber (1) according to claim 1, wherein the rotor array (4, 5) is mechanically operatively connected to the circular plate member (8).

7. The gas scrubber (1) according to claim 1, further comprising a first baffle plate (16) on the outer circumference of the gas scrubber (1).

8. The gas scrubber (1) according to claim 7, further comprising a second baffle plate (17) arranged at a radial distance from the first baffle plate (16).

9. The gas scrubber (1) according to claim 1, further comprising a motor (19) to drive of the circular plate member (8).

10. The gas scrubber (1) according to claim 1, further comprising an adjustable bypass (22).

11. The gas scrubber (1) according to claim 1, wherein the outlet nozzle (12) is configured in the form of a full jet nozzle (26).

12. The gas scrubber (1) according to claim 11, wherein the waste gas inlet (2) has a cleaning nozzle (23) configured for removing adhesions from the walls and/or at the rear of the full jet nozzle (26).

13. The gas scrubber (1) according to claim 1, wherein the inner and/or the outer rotor array (4, 5) and/or the inner and/or outer stator array (6, 7) has/have a plurality of projections (24) distributed along the circumference.

14. The gas scrubber (1) according to claim 13, wherein the projections (24) extend in a direction essentially parallel to the axis (11) of the circular plate member (8).

15. The gas scrubber (1) according to claim 1, wherein the rotor array (4, 5) and/or the stator array (6, 7) and/or the circular plate member (8) is/are made of plastic, fiberglass-reinforced plastic (FRP) or carbon-fiber reinforced plastic (CFRP).

16. The gas scrubber (1) according to claim 1, wherein the waste gas outlet (3) defines an opening, and the liquid outlet (14) defines a second opening, and wherein the opening and the second opening are arranged to permit the gas scrubber (1) to be operably mounted either in a vertical or in a horizontal position.

17. A waste gas treatment system (25) with a gas scrubber (1) according to claim 1.

18. The waste gas treatment system (25) according to claim 17, comprising a thermal reactor (27) selected from the group consisting of a combustion reactor and a wet scrubber (28).

19. The waste gas treatment system (25) according to claim 18, wherein the thermal reactor (27) is a wet scrubber (28) and wherein the gas scrubber (1) is arranged downstream from the wet scrubber (28) as seen in the direction of flow of the waste gas stream.

20. The waste gas treatment system (25) according to claim 18, wherein the thermal reactor (27) is a wet scrubber (28) and wherein the gas scrubber (1) is arranged downstream from the wet scrubber (28) as seen in the direction of flow of the waste gas stream, and the wet scrubber (28) is arranged downstream from the thermal reactor (27).

Description

DESCRIPTION OF THE DRAWINGS

[0066] In this context, the following is shown, at times schematically:

[0067] FIG. 1a schematic view of the gas scrubber with a horizontal axis of rotation,

[0068] FIG. 2a view of the gas scrubber with a vertical axis of rotation,

[0069] FIG. 3a rotary atomizer,

[0070] FIG. 4a schematic view of the gas scrubber with stator arrays on a cover disk,

[0071] FIG. 5an embodiment of the gas scrubber with a bypass and bypass openings,

[0072] FIG. 6a waste gas treatment system with a gas scrubber and a wet scrubber,

[0073] FIG. 7 a waste gas treatment system with a gas scrubber, a wet scrubber and a thermal reactor, and

[0074] FIG. 8a schematic view of the gas scrubber with an impeller having a circular plate member, a rotary atomizer and rotor arrays.

DETAILED DESCRIPTION

[0075] For the sake of greater clarity, identical components or those having the same effect are provided with the same reference numerals in the figures of the drawing described below, making reference to an embodiment.

[0076] FIG. 1 shows a gas scrubber 1 for removing particles, especially dust, from a waste gas.

[0077] In a housing 10 of the gas scrubber, there is a waste gas inlet 2 for the waste gas that is to be cleaned and a waste gas outlet 3 for the gas that has been cleaned.

[0078] The gas scrubber 1 also has an essentially circular plate member 8 that is arranged in the housing 10 so that it can rotate around its own axis 11. The waste gas can be fed in approximately in the center 15 of the plate member 8 via the waste gas inlet 2.

[0079] FIG. 1 also shows an outlet nozzle 12 for spraying a liquid 13, especially a cleaning or scrubbing liquid, onto the plate member 8, in order to obtain a mixture consisting of waste gas and liquid 13 in front of the plate member 8.

[0080] In the present embodiment, the outlet nozzle 12 can be configured in the form of a full jet nozzle 26 and it can direct a liquid jet onto the center 32 of the rotary atomizer 20, thus supplying it with the liquid 13 that is to be atomized. This type of liquid feed is considerably simpler to implement mechanically than a feed via the rotating shaft. In comparison to other nozzles, the full jet nozzle can convey more liquid at the same liquid pressure. In particular, the liquid 13 can be fed in only in the center of the rotary atomizer 20, so that a uniform film can form on the surface of the rotary atomizer 20.

[0081] The gas scrubber 1 also has at least one inner rotor array 4 and one outer rotor array 5 arranged at a distance from the inner rotor array 4, both of which can be rotated around the shaft 11.

[0082] Moreover, there is at least one inner stator array 6 and one outer stator array 7 arranged at a distance from the inner stator array 6, whereby, in order to generate turbulence, the rotor arrays 6, 7 and the stator arrays 4, 5 are arranged alternatingly and concentrically relative to each other, so that particles from the waste gas stream can be transferred into the liquid 13.

[0083] FIG. 1 shows an embodiment with a horizontal axis of rotation.

[0084] FIG. 2 shows an embodiment with a vertical axis of rotation.

[0085] In the present embodiment as shown in FIGS. 1 and 2, the inner and outer rotor arrays 4, 5 are driven by a shared shaft. For this purpose, the rotor arrays 4, 5 are mechanically operatively connected—in the present case, arranged on—the circular plate member 8.

[0086] A motor 19, especially an electronically commutated motor, is provided as the drive of the circular plate member 8.

[0087] As can be seen in FIG. 8 and FIG. 4, in the present embodiment, the inner and/or the outer rotor array 4, 5 and/or the inner and the outer stator array 6, 7 have a plurality of projections 24, preferably distributed along the circumference, which here are configured in the form of rods. Other geometrical shapes such as blocks or flat rods, angled irons, square irons, wings or blade rings, which are arranged so as to rotate or so as to be stationary, are all likewise conceivable. There can also be blades with edges so that no curvature is necessary, thus simplifying their production.

[0088] As can be seen in FIGS. 1 and 2, the projections 24 extend in a direction essentially parallel to the shaft 11 of the circular plate member 8. Therefore, like with a fan, the projections 24 generate a pressure that makes the gas flow, especially the cleaned gas.

[0089] The rotor arrays 4, 5 and/or the stator arrays 6, 7 and/or the circular plate member 8 can be made of plastic, especially fiberglass-reinforced plastic (FRP) or carbon-fiber reinforced plastic (CFRP).

[0090] FIGS. 1 and 2 likewise show a first baffle plate 16 which is provided on the outer circumference of the gas scrubber 1. A second baffle plate 17 is arranged at a radial distance from the first baffle plate 16.

[0091] The mixture consisting of liquid 13 and gas strikes the first baffle plate 16 and is deflected to the side. The second baffle plate 17 can deflect the gas again in the opposite direction. In this process, droplets are separated out of the gas. Moreover, at the end of the baffle plate 16, there can be a perforated plate through which the mixture passes. The flow is calmed in this process and decelerated in the tangential direction and deflected outward in the radial direction. This reduces the formation of new droplets from the liquid that has already been precipitated.

[0092] The second baffle plate 17 is arranged at a radial distance from the first baffle plate 16. The gas is conveyed around the first baffle plate 16 and then in the opposite direction around the second baffle plate 17, whereby liquid and gas are separated again. The gas is then discharged sideways or upwards in the outside area of the housing 10 through the waste gas outlet 3, and the liquid is drained downwards through the liquid outlet 14. This deflection of the gas allows a separation of the liquid, and on the way, droplets still contained in the gas stream can be precipitated onto the walls. In particular, a drain slit 18 can be provided in the second baffle plate 17 in order to drain the liquid.

[0093] As can be seen in FIG. 5, the openings for the waste gas outlet 3 and for the liquid outlet 14 are arranged in such a way that the gas scrubber 1 can be mounted in a vertical as well as in a horizontal position. Depending on the installed position, the openings that are not needed can be closed with a blind flange.

[0094] FIGS. 1, 2, 5 and 6 show the rotary atomizer 20 which serves to atomize the mixture consisting of waste gas and liquid 13 which, in the present embodiment, is arranged on the circular plate member 8. The detailed view as shown in FIG. 3 likewise depicts the rotary atomizer 20. In this context, the rotary atomizer 20 is arranged on the circular plate member 8. The rotary atomizer 20 effectuates a fine atomization of the liquid 13, especially in comparison to atomization from a nozzle using water pressure.

[0095] As can also be seen in FIG. 3, the rotary atomizer 20 is configured as a disk with an atomization edge 21 and it is shaped so as to be concave towards its outer edge in order to pick up the jet of liquid 13 from the outlet nozzle 12 as completely as possible, without back-splashing on the surface, and then distribute it uniformly. Moreover, the center 32 of the rotary atomizer 20 has a convex elevation 33 that preferably reaches or exceeds the height of the atomization edge 21.

[0096] In particular, the rotary atomizer 20 can have the shape of a sombrero. The sombrero shape is characterized by the fact that the thickness is greater at the edge as well as in the center. When the total thickness of the atomizer is plotted over the diameter, the curve of the thickness approximates the shape of a sombrero.

[0097] The sprayed-out liquid 13 strikes the center 32 of the rotary atomizer 20. The liquid 13 is uniformly distributed in the form of a film on the surface of the rotary atomizer 20 and is centrifuged outwards by the rotation. The liquid 13 atomizes into fine droplets at the edge of the rotary atomizer 20. In particular, the diameter of the rotary atomizer 20 can be approximately the same as the diameter of the waste gas inlet 2.

[0098] Subsequently, the mixture consisting of droplets and gases strikes the inner stator array 6 and is then picked up by the inner rotor array 4. Subsequently, the mixture is flung onto the outer stator array 7 and onto the outer rotor array 5.

[0099] As mentioned above, the mixture consisting of liquid 13 and gas strikes the first baffle plate 16 and is deflected to the side, and it can then be deflected again in the opposite direction by the second baffle plate 17.

[0100] The gas is then discharged sideways or upwards in the outside area of the housing 10 through the waste gas outlet, and the liquid 13 is drained downwards through a liquid outlet 14.

[0101] As can especially be seen in FIG. 5, the waste gas inlet 2 has a cleaning nozzle 23, especially a hollow cone nozzle or a full cone nozzle, for purposes of removing adhesions to the walls and/or at the rear of the full jet nozzle 26.

[0102] The rotor-stator array generates a pressure differential by means of which the gas is conveyed from the waste gas inlet 2 to the waste gas outlet 3.

[0103] FIGS. 1, 2, 5 and 6 show an adjustable bypass 22. The bypass 22 returns gas that has already passed once through the rotor-stator array back into the rotor-stator array. This increases the gas flow through the rotor-stator array, and the pressure generated by the rotor array 4, 5 between the waste gas inlet 2 and the waste gas outlet 3 is reduced. Since the gas and the liquid 13 pass through the array 4, 5 several times, the interaction between the gas and the liquid 13 is increased and a greater efficiency is attained for the precipitation of the particles and dust.

[0104] The bypass 22 can be configured in the form of a connection of the waste gas outlet 3 to the waste gas inlet 2 outside of the housing 10. For purposes of bypass regulation 31, this connection can have a conventional control valve that adjusts the gas flow through the bypass 22.

[0105] The bypass 22 can also be implemented as a “short-circuit” inside the housing 10, whereby the gas is conveyed out of the area in front the first baffle plate 16 behind the cover disk 9 and from there, back into the area of the rotor and stator array. The outlet for the return flow of the gas into the rotor-stator array can be provided in the form of bypass openings 30 in the cover disk 9, especially also between the stator arrays 6, 7, or else in the area of the gas inlet 2.

[0106] The bypass regulation 31 can be effectuated, for instance, by an orifice plate with adjustable openings on the outer circumference of the stator in the area behind the cover disk 9.

[0107] FIG. 4 shows a view from above onto the cover disk 9 when the housing lid and the motor 19 with the circular plate member 8 have been removed. The stator arrays 6, 7 are arranged on the cover disk 9. Bypass openings 30 perforate the cover disk so that the gas from the bypass can flow back again into the rotor-stator array. The cover disk 9 improves the inflow.

[0108] The waste gas inlet 2 can be seen centrally from below. The bypass regulation 31 is effectuated by a rotatable orifice plate that is arranged on the circumference of the cover disk 9 between the cover disk 9 and the bottom of the housing. The second baffle plate 17 is configured so as to be closed at the halfway point of the housing towards the waste gas outlet 3 all the way to the housing lid so that the gas can flow only in the other half of the housing into the outer area of the housing 10, thus having to travel a longer distance through the housing 10 until it reaches the waste gas outlet 3. This translates into a better precipitation of droplets out of the gas stream.

[0109] FIG. 5 shows an embodiment with bypass openings 30 in the cover disk 9 between the inner and outer stator arrays 6, 7. In this context, auxiliary nozzles 29 can bring additional liquid 13 through the bypass openings 30 into the area of the outer stator array 7 and the rotor array 5. This can improve the efficiency of the gas scrubber 1 if the liquid 13 which had been sprayed by the rotary atomizer 20 onto the first rotor array has already partially flowed onto the cover disk 9 or onto the circular plate member 8, and therefore is no longer available to interact with the particles or the dust contained in the gas.

[0110] The auxiliary nozzles 29 can be directed towards the bypass openings 30 in the cover disk 9 or else sideways, for example, tangentially, into the space used as the bypass 22 behind the cover disk 9.

[0111] Within the scope of the invention, a waste gas treatment system 25 is being put forward which can comprise a gas scrubber 1 of the type described above. FIGS. 6 and 7 show embodiments of such a waste gas treatment system 25. The combination of a thermal method and wet scrubbing is normally employed in the semiconductor industry for purposes of treating flammable, toxic and corrosive gas mixtures.

[0112] FIG. 6 shows an embodiment of the waste gas treatment system 25 with bypass openings 30 in the area of the waste gas inlet 2. In this context, the bypass regulation 31 can be carried out directly by changing the free cross section of the bypass openings 30 employing a sliding or rotating orifice plate.

[0113] In the embodiment shown in FIG. 6, the gas scrubber 1 is installed on a wet scrubber 28. Here, the bypass openings 30 can simultaneously serve as the liquid outlet 14, so that the draining liquid drains via the waste gas inlet 2 directly into the wet scrubber 28. In this process, a portion of the waste gas circulates multiple times through the gas scrubber 1 and is thus treated multiple times. This increases the efficiency of the gas scrubber.

[0114] Since, in order to achieve a high degree of efficiency of the dust precipitation, it is always necessary to select the highest possible rotational speed for the plate member 8, the pressure differential over the gas scrubber 1 between the waste gas inlet 2 and the waste gas outlet 3 is adjusted by regulating the bypass cross section via the modality of bypass regulation 31. Due to the cooling of the gas by the liquid contained in the gas scrubber 1, the throughput rate or the pressure can be regulated by means of the bypass 22 without the device heating up. On the other hand, in “dry systems”, that is to say, in the case of fans, this is only possible to a limited extent without liquid cooling since the circulating air in the system would heat up and the system would overheat.

[0115] FIG. 7 shows an embodiment of the waste gas treatment system 25 with a thermal reactor 27 which can be configured as a combustion reactor. A wet scrubber 28 is likewise put forward.

[0116] In the present embodiment, the gas scrubber 1 is arranged downstream from the wet scrubber 28 as seen in the direction of flow of the waste gas stream and the wet scrubber 28 is arranged downstream from the thermal reactor 27. In this manner, the gas scrubber 1 is not arranged directly downstream from the thermal reactor 27, so that the gas is already at a lower temperature.

[0117] Owing to the compactness of the gas scrubber 1, it is possible to attain a compact installation on the wet scrubber 28. Another advantageous aspect of this arrangement is the reduced concentration of corrosive gases as well as a lower temperature of the mixture. Moreover, the scrubbing liquid from the wet scrubber 28 can be employed as the liquid 13, so that there is no need for additional consumption of water or liquid.

LIST OF REFERENCE NUMERALS

[0118] 1 gas scrubber

[0119] 2 waste gas inlet

[0120] 3 waste gas outlet

[0121] 4 inner rotor array

[0122] 5 outer rotor array

[0123] 6 inner stator array

[0124] 7 outer stator array

[0125] 8 circular plate member

[0126] 9 cover disk

[0127] 10 housing

[0128] 11 axis/shaft of the plate member

[0129] 12 outlet nozzle

[0130] 13 liquid

[0131] 14 liquid outlet

[0132] 15 middle of the plate member

[0133] 16 first baffle plate

[0134] 17 second baffle plate

[0135] 18 drain slit

[0136] 19 motor

[0137] 20 rotary atomizer

[0138] 21 atomization edge

[0139] 22 bypass

[0140] 23 cleaning nozzle

[0141] 24 projections

[0142] 25 waste gas treatment system

[0143] 26 full jet nozzle

[0144] 27 thermal reactor

[0145] 28 wet scrubber

[0146] 29 auxiliary nozzle

[0147] 30 bypass opening

[0148] 31 bypass regulation

[0149] 32 center of the rotary atomizer

[0150] 33 convex elevation of the rotary atomizer