Patent Application
20210387129
The invention relates to a gas scrubber for removing particles from a waste gas and to a waste gas treatment system with a gas scrubber.
In the semiconductor industry, thin layers are often applied onto various substrates by means of a chemical reaction from the gas phase (chemical vapor deposition—CVD) and these layers are then structured through the modality of etching with reactive gases. Such processes give rise to mixtures of toxic, flammable, corrosive or condensing gases. For this reason, these gas mixtures have to be treated as close as possible to the place where they are generated. The chemical reaction of these mixtures often generates ultrafine particles in the order of magnitude of <1 μm that cannot be completely washed out by conventional gas scrubbers. Even electrostatic precipitators are unsuitable in the case of very high particle concentrations.
Different technologies are employed when it comes to the use of systems for waste gas treatment as well as for waste air treatment. For instance, waste gases can be burned, washed out or freed of the ultrafine particles. In order to treat waste gases stemming from the manufacture of semiconductor products such as, for example, silicon-based solar modules or LEDs, such systems are normally operated continuously, that is to say, 24 hours per day, seven days per week. However, the invention also encompasses devices that are used for treating a waste gas stream, for example, a process gas stream. Such a waste gas stream can be re-used within a process chain after having been treated in a separator.
These problems can be solved by a generic device for treating a gas stream. In principle, gas scrubbers or else wet scrubbers are well suited to remove water-soluble gases from a waste air stream. Acidic and alkaline gases can be reduced to a low level by chemical absorption with alkaline or acidic scrubbing liquids.
Gas scrubbers serve to remove solid, liquid or gaseous contaminants from a gas, whereby the contaminants are bound to the scrubbing liquid that has been introduced into the gas stream and are precipitated together with the scrubbing liquid.
The mode of action of generic gas scrubbers or wet scrubbers or wet separators is based on an approach in which gases or particles from a gas stream laden with gases or particles are transferred into a liquid. For this purpose, appropriate interfaces have to be formed between the gas and the liquid, and a relative movement between these two phases has to be generated. One method for creating interfaces entailing the best possible intimate mixing of the gas and the liquid is to disperse one phase into the other. In other words, for example, bubble swarms are formed in a liquid, or else droplet collectives are formed in a gas, or else systems are created in which the liquid is present in the form of a more or less dispersed jet. Another fundamental way to bring the gas and the liquid into contact with each other is to pass the gas around wetted packings.
Therefore, the gas scrubber or wet scrubber constitutes a simple method for treating waste air or waste gas, whereby the gas that is to be cleaned is brought into contact with finely dispersed water droplets or with another scrubbing liquid in a parallel current or in a countercurrent, so as to clean the contaminated gas stream.
Gas scrubbers are known from the state of the art. For instance, German patent specification DE 564 429 C discloses a gas scrubber having rotating and stationary rods. The combination of the stationary and rotating rods is intended to improve the degree of purity achieved by gas scrubbers. The rotating rods can be set diagonally to the axis of the gas scrubber, and the stationary rods can be configured in the form of flat rods, blades or angled irons.
German patent specification DE 358 122 C discloses a device having two or more concentric blade rings for purposes of cleaning, cooling and mixing gases.
German laid-open application DE 369 224 A1 discloses a device to wash out tar or to absorb or enrich a scrubbing liquid. In this process, tar is to be separated out of hot gases containing tar and then employed to scrub said gases.
Moreover, European patent EP 0 048 012 B1 discloses a device for the ultrafine comminution of inorganic substances.
British patent application GB 191 022 433 A discloses a device having perforated sections. This device essentially consists of perforated cylinders or conical housings that rotate relative to each other, or else some of them rotate and some of them are stationary. The cylinders or housings are arranged concentrically in one or more chambers and they can have deflecting walls or deflecting rods that are curved inwards.
German patent application DE 33 36 840 A1 discloses a device with perforated walls for mass transport as well as for the precipitation of dust and droplets.
Moreover, PCT International Application WO 2012/146558 A2 discloses a wet separator having two single-piece corrugated sheets with different corrugation shapes and perforated flanks.
German translation of published international application DE 602 12 546 T2 or European patent EP 1 310 289 B1 discloses a gas scrubber having a housing in which an impeller rotates around its own axis, whereby a waste gas is introduced into the center of the impeller. A cleaning liquid is sprayed into the impeller. A baffle is arranged at a distance from the impeller and surrounds it. A mixture of the waste gas and the cleaning liquid strikes the baffle. The baffle in the gas scrubber promotes the agitation or movement of the waste gas and of the cleaning liquid as well as an atomization of the cleaning liquid, as a result of which dust particles contained in the waste gas are supposed to be efficiently absorbed in the cleaning liquid.
German translation of published international application DE 603 018 64 T2 or European patent EP 1 480 731 B1 discloses a gas scrubber for removing dust from a waste gas, comprising a housing in which an impeller is accommodated and supported by a shaft. Dust contained in the waste gas is supposed to be captured by means of a cleaning liquid. Moreover, a plurality of projections is provided around the impeller in such a way that the waste gas and the cleaning liquid discharged from the impeller strike these projections.
A drawback of such systems is their geometrical dimensions and large weight since, due to their size, it is sometimes difficult to transport the systems to their destination and/or installation site. Compact models of such systems have very little effect in the case of ultrafine particles, especially those with a diameter in the order of magnitude of less than 1 μm.
Before the backdrop of the disadvantages described above, the invention is based on the objective of putting forward a gas scrubber and a waste gas treatment system which ensure a higher degree of purity of a cleaned waste gas thanks to an improved removal of the particles or dust from the waste gas, namely, the invention puts forward a gas scrubber that has been optimized in terms of the specific restrictions regarding size, efficiency and pressure drop as well as a waste gas treatment system, without reducing the capacity of the waste gas treatment system.
According to the invention, a gas scrubber for removing particles, especially dust, from a waste gas is provided, comprising a housing with a waste gas inlet and a waste gas outlet, comprising an essentially circular plate member that is arranged in the housing so that it can rotate around its own axis, whereby the waste gas can be fed in via the waste gas inlet approximately in the center the plate member, and comprising an outlet nozzle for purposes of spraying a liquid, especially a cleaning liquid or a scrubbing liquid, onto the plate member in order to obtain a mixture of waste gas and liquid in front of the plate member.
Moreover, at least one inner rotor array and one outer rotor array situated at a distance from the inner rotor array are provided, both of which can be rotated around the axis.
Moreover, the gas scrubber has at least one inner stator array and one outer stator array arranged at a distance from the inner stator array, whereby, in order to generate turbulence, the rotor arrays and the stator arrays are arranged alternatingly and concentrically relative to each other, so that particles from the waste gas stream can be transferred into the liquid.
According to the invention, the gas scrubber has a rotary atomizer for atomizing the liquid, said rotary atomizer, and it is especially arranged on the circular plate member.
The sprayed-out liquid strikes the center of the rotary atomizer. The liquid is uniformly distributed in the form of a film on the surface of the rotary atomizer and is centrifuged outwards by the rotation. The liquid atomizes into fine droplets at the edge of the rotary atomizer. In particular, the diameter of the rotary atomizer can be approximately the same as the diameter of the waste gas inlet.
The mixture of droplets and gases strikes the innermost stator and is then picked up by the innermost rotor. Subsequently, the mixture is flung onto the outer stator and onto the outer rotor.
The gas is then discharged sideways or upwards in the outside area of the housing through the waste gas outlet, and the liquid is drained downwards through a liquid outlet.
The rotor-stator array generates a pressure differential by means of which the gas is conveyed from the waste gas inlet to the waste gas outlet.
The rotary atomizer effectuates a fine atomization of the liquid, especially in comparison to atomization from a nozzle using water pressure.
Moreover, there is no need for a high pressure at the liquid feed. Furthermore, no additional media are necessary as is the case with so-called two-media nozzles used for atomizing the scrubbing liquid, in other words, especially there is no need for compressed air either.
According to a first advantageous embodiment of the invention, the rotary atomizer is configured as a disk with an atomizing edge. Rotary atomizers create a narrow distribution of the droplet sizes and do not become clogged, in addition to which they require only a low liquid pressure and no compressed gas in order to generate the droplets. A thin liquid film is formed on the rotary atomizer and it becomes thinner towards the outside due to the centrifugal acceleration, and it disintegrates very uniformly into droplets at the atomization edge.
Moreover, the atomization edge of the rotary atomizer can be configured so as to be as sharp as possible. The atomization edge should be located in the center plane of the impeller channel between the plate member and a cover disk.
According to an advantageous refinement of the invention, the rotary atomizer is shaped so as to be concave towards its outer edge in order to thus yield a targeted distribution of the droplets.
The rotary atomizer exhibits a particularly small droplet spectrum and brings about an improvement in the precipitation rate. Since the atomization is achieved by means of the centrifugal forces, less admission pressure is needed in the liquid feed line than when compared to full cone nozzles. Consequently, pumps can be used that are less expensive and more resistant to dirt particles.
According to another advantageous variant of the invention, it is provided for the center of the rotary atomizer to have a convex elevation that preferably reaches or exceeds the height of the atomizing edge. This embodiment is advantageous in comparison to prior-art embodiments of rotary atomizers which have an approximately cup-like design and which are fed via the shaft and not via an external full jet nozzle; in this context, see, for instance, European revised patent EP 0 463 742 B2.
It can be provided for the interior of the rotary atomizer to have a convex configuration on its axis of rotation so that it can pick up the jet of liquid from the outlet nozzle as completely as possible, without back-splashing on the surface, and then distribute it uniformly.
In particular, the rotary atomizer 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.
In an advantageous refinement of the invention, the inner and outer rotor arrays are driven by a shared shaft. This simplifies the structure, and the gas scrubber is rendered altogether more compact.
In an advantageous manner, the rotor array is mechanically operatively connected to—especially arranged on—the circular plate member. Particularly when it comes to high rotational speeds, it is advantageous for the impeller to be made out of a single piece consisting of the plate member together with the rotor arrays. The rotary atomizer can be glued on or welded on since it is preferably arranged centrally on the plate member and is thus subject to a uniform force in all directions and also to a centrifugal acceleration that is not very great.
According to another advantageous embodiment of the invention, a first baffle plate is provided on the outer circumference of the gas scrubber. The mixture consisting of liquid and gas strikes the first baffle plate and is deflected to the side. An optional, second baffle plate 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 first baffle plate, 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.
According to an advantageous embodiment of the invention, a second baffle plate is arranged at a distance from the first baffle plate. The gas is conveyed around the first baffle plate and then in the opposite direction around the second baffle plate, whereby liquid and gas are separated again. The gas is then discharged sideways or upwards in the outside area of the housing through the waste gas outlet, and the liquid is drained downwards through the liquid outlet. 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 on the walls.
In particular, a drain slit can be provided in the second baffle plate in order to drain the liquid.
A refinement of the invention puts forward a motor, especially an electronically commutated motor, as the drive of the circular plate member. This motor has a high power density, that is to say, its power relative to the motor dimensions, in comparison, for instance, to asynchronous motors. Moreover, this type of motor displays higher energy efficiency. Its relatively smaller structural height and structural width contribute to the compactness of the gas scrubber which, in turn, allows simple integration into existing systems and devices such as, for example, waste gas treatment systems.
Furthermore, a gasket, especially a meander gasket, can be provided behind the plate member for purposes of protecting the bushing of the motor shaft at the rear of the housing. This gasket can be rinsed in the vicinity of the shaft with small amounts of a clean liquid so that particles that have been entrained over the course of time can be once again rinsed away from the shaft.
An advantageous embodiment of the invention provides for an adjustable bypass. The bypass returns gas that has already passed once through the rotor-stator array again into the rotor-stator array. This increases the gas flow through the rotor-stator array, and the pressure generated by the rotor between the waste gas inlet and the waste gas outlet is reduced. Since the gas and the liquid pass through the array several times, the interaction between the gas and the liquid is increased and a greater efficiency is attained for the precipitation of dust.
The bypass can be configured in the form of a connection of the waste gas outlet to the waste gas inlet outside of the housing. For purposes of bypass regulation, this connection can have a conventional control valve that adjusts the gas flow through the bypass.
The bypass can also be implemented as a “short-circuit” inside the housing, whereby the gas is conveyed out of the area in front of the first baffle plate behind the cover disk 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 in the cover disk, especially also between the rows of stators, or else in the area of the gas inlet. The bypass regulation 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.
According to another advantageous embodiment of the invention, the outlet nozzle is configured in the form of a full jet nozzle. This nozzle configured as a full jet directs a water jet onto the center of the rotary atomizer, supplying it with the liquid 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 can be fed in only in the center of the rotary atomizer, so that a uniform film can form on the surface of the rotary atomizer.
In contrast to other nozzles that are suitable for atomization, the full jet nozzle does not require narrow channels or inserts in order to generate turbulence in the nozzle. A full jet nozzle has a simple channel in the interior, no inserts for turbulence generation like, for example, hollow cone nozzles or full cone nozzles, so that it is impervious to particles contained in the liquid. For this reason, scrubbing liquid that is already contaminated with particles, for instance, from a wet scrubber located upstream, can also be used.
An advantageous refinement of the invention provides for the waste gas inlet to have a cleaning nozzle, 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.
Since gases heavily laden with dust are scrubbed in the gas scrubber, dust deposits are to be expected in all areas of the feed line, especially in those places where the flow is turbulent. This is why it has to be easy to clean the entire feed line, including the waste gas inlet, or else it has to be self-cleaning. The liquid coming out of the cleaning nozzle scrubs the wall of the waste gas inlet. The advantage of a hollow cone nozzle lies in the fact that the exiting liquid is directed primarily at the wall of the gas inlet, thereby cleaning it without disrupting the formation of droplets on the rotary atomizer. A full cone nozzle could influence the liquid film on the surface of the rotary atomizer but it could also remove adhesions at the rear of the outlet nozzle. A cleaning nozzle configured as a full cone nozzle can introduce additional liquid into the rotor-stator array outside of the plane of the rotary atomizer, thus improving the efficiency of the gas scrubber.
According to another advantageous embodiment of the invention, the inner and/or outer rotor array and/or the inner and/or outer stator array has/have a plurality of projections, preferably distributed along the circumference, especially in the form of rods and/or blocks and/or blades.
Therefore, like with a fan, the projections generate a pressure that makes the gas flow, especially the cleaned gas. The projections can have a rectangular, triangular or round cross section in a plane perpendicular to the axis of the circular plate member. These can be flat rods, angled irons, square irons, wings or blade rings, which are arranged so as to rotate or so as to be stationary. There can also be blades with edges so that no curvature is necessary, thus simplifying their production. These edges can be configured so as to be rotation-symmetrical. However, arcs or radial side edges are likewise conceivable. It can be provided for the projections of the outer rotor array to be shorter than the projections of the inner rotor array. In this manner, the turbulence is increased, thus yielding a more efficient atomization.
Advantageously, the projections can extend in a direction essentially parallel to the axis of the circular plate member.
Tilted projections that especially are likewise conceivable yield aerodynamic advantages. When the rotor projections are made of a solid material, they can be simply machined from the impeller if they are parallel to the axis.
According to an advantageous refinement of the invention, it is provided for the rotor array to be made of plastic, especially fiberglass-reinforced plastic (FRP) or carbon-fiber reinforced plastic (CFRP). As an alternative or in addition, it is likewise conceivable for the stator array and/or for the circular plate member to be made of such a plastic.
Plastic is corrosion-proof and it is relatively lighter in weight than corresponding versions made of metal. By using a solid material or else very sturdy composite materials such as FRP or CFRP, very small diameters and high rotational frequencies are possible. Moreover, a rotor and/or stator array made of plastic is relatively lighter in weight. All in all, this translates into a compact design of the gas scrubber for decentralized applications. Moreover, the versions made of plastic are less expensive than those made of other materials such as, for instance, corrosion-proof metal alloys.
The rotor array can be milled out of a solid material together with the circular plate member. As a result, there is no need for glued or screwed connections, and an excellent mechanical stability is ensured that allows high rotational speeds.
In a particularly advantageous embodiment of the invention, the openings for the waste gas outlet and for the liquid outlet are arranged in such a way that the gas scrubber can be mounted in a vertical as well as in a horizontal position, thereby ensuring high flexibility when it comes to its installation. In other words, the openings are arranged in such a way that, in the vertical as well as in the horizontal installed positions of the gas scrubber, the openings for the liquid outlet face downwards and the openings for the waste gas outlet face sideways or upwards.
An independent idea of the invention puts forward a waste gas treatment system with a gas scrubber, especially of the type described above.
Advantageously, the waste gas treatment system can have a thermal reactor, particularly a combustion reactor and/or a wet scrubber.
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. The oxidation of, for example, siliceous components gives rise to very fine dust having particle sizes well below 1 pm, which can only be partially scrubbed out by conventional wet scrubbers such as, for example, packed columns. For this reason, in processes involving a very pronounced formation of particles, there is a need for an additional treatment step in order to reduce the remaining dust emission.
In a refinement of the invention, the gas scrubber is arranged downstream from the wet scrubber as seen in the direction of flow of the waste gas stream.
The compactness of the gas scrubber allows for a compact installation on the wet scrubber, often even inside an enclosure of the waste gas treatment system. 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 can be employed to supply the gas scrubber, so that there is no need for additional consumption of water or liquid. Furthermore, no additional pump is required for the liquid. After all, the pump output of the wet scrubber circulation system is normally sufficient to feed the liquid into the outlet nozzle of the gas scrubber since it only requires a low pressure.
According to another variant of the invention, it can be provided for the gas scrubber to be arranged downstream from the wet scrubber as seen in the direction of flow of the waste gas stream, and for the wet scrubber to be arranged downstream from the thermal reactor.
In this manner, the gas scrubber is not arranged directly downstream from the thermal reactor, so that the gas is already at a lower temperature. A greater distance from the reactor offers protection against overheating caused by residual heat from the thermal reactor, especially in the case of a sudden failure of the device.
Additional objectives, advantages, features and application possibilities of the present invention ensue from the description below of an embodiment making reference to the drawing. In this context, all of the described and/or depicted features, either on their own or in any meaningful combination, constitute the subject matter of the present invention, also irrespective of their compilation in the claims or the claims to which they refer back.
In this context, the following is shown, at times schematically:
an embodiment of the gas scrubber with a bypass and bypass openings,
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.
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.
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.
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.
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.
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.
In the present embodiment as shown in
A motor 19, especially an electronically commutated motor, is provided as the drive of the circular plate member 8.
As can be seen in
As can be seen in
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).
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.
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.
As can be seen in
As can also be seen in
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.
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.
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.
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.
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.
As can especially be seen in
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.
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.
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.
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.
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.
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.
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.
In the embodiment shown in
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.
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.
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.
1 gas scrubber
2 waste gas inlet
3 waste gas outlet
4 inner rotor array
5 outer rotor array
6 inner stator array
7 outer stator array
8 circular plate member
9 cover disk
10 housing
11 axis/shaft of the plate member
12 outlet nozzle
13 liquid
14 liquid outlet
15 middle of the plate member
16 first baffle plate
17 second baffle plate
18 drain slit
19 motor
20 rotary atomizer
21 atomization edge
22 bypass
23 cleaning nozzle
24 projections
25 waste gas treatment system
26 full jet nozzle
27 thermal reactor
28 wet scrubber
29 auxiliary nozzle
30 bypass opening
31 bypass regulation
32 center of the rotary atomizer
33 convex elevation of the rotary atomizer
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 115 890.4 | Jun 2020 | DE | national |
