DE19733256A1 - Wet flue gas desulphurisation - Google Patents

Abstract

A method to wet flue gas desulphurisation involves flowing flue gas (1) to be purified, as main stream from bottom to the top using an adsorber tower (2) including a washing solution (3). The solution (3) is removed from a reaction tank (15) and sprayed in the absorber tower (2) and brought into contact, where a gas-/drop flow (12) is formed. A uniform flow of flue gas steam (1) and the scrubbing fluid stream (3) passes over the divided cross-section of the absorber tower, at a rate where the mid gas speed (vg) > 5m/s. Gas speed (vg) is adjusted in the gas-/drop stream (12). The gas speed is > than the drop-speed (Vt). The drops are transported or at least stopped by the gas stream (1). The relative speed between the gas stream (1) and drops from the scrubbing fluid (3) is lowered to a specified value. The drops fall down and the scrubbing fluid (3) is feed back to the reaction tank (15). Also claimed is the apparatus used for the above method.

Description

Technical field

The invention relates to the field of flue gas cleaning. It affects one Method and device for wet flue gas desulfurization, in which the flue gas is brought into intimate contact with a liquid washing solution and the reaction products are in aqueous form.

State of the art

When burning coal and oil as well as household and industrial waste in addition to other pollutants, sulfur compounds from the exhaust gas can be removed by treatment in desulfurization plants. This anla gen work by means of additive, dry or wet processes.

In the wet cleaning process, the flue gas to be cleaned is processed in one step sorberturm brought into so close contact with the washing liquid that a substance transport from the gas phase to the liquid phase takes place. That happens through Spray the washing liquid into the flue gas stream. From the liquid phase the gases are then absorbed. The absorption process is mainly affected  flows through the available exchange area and its constant Er innovation, the dwell time in the absorption space and the washing liquid used speed.

In the wet processes known today, the limestone washing process has become established worldwide. In this process, exhaust gases are sprayed in an absorber with an aqueous suspension of limestone and thereby largely freed from the pollutants SO ₂ , HCl and HF. The pure gases are heated up again after passing through a droplet separator and led into the chimney. The calcium sulfite that primarily forms in the reaction in the absorber is oxidized to gypsum with oxidation air. A partial stream of the suspension containing gypsum is removed from the process and dewatered.

All process steps necessary for the physical and chemical processes such as absorption, oxidation, neutralization and droplet separation run in the Washer, which is usually designed as a washing tower.

The washing systems are designed differently in the flue gas duct, where with these when trickling in countercurrent or cocurrent or in combination done by both (Dubbel, paperback for mechanical engineering, 18th edition 1995, Springer Verlag, L55). Known prior art is that the flue gas flows from bottom to top, with either a vertical or a tangentia The inlet for the flue gas in the scrubber can be selected.

The most common are the absorber towers for separating out sulfur dioxide Flue gas constructed so that it works in the counterflow principle (see e.g. K.J. Thomé-Kozmiensky: Thermal waste treatment, EF publishing house for energy and Umwelttechnik GmbH, 1994, p. 485).  

Limestone suspension is sprayed in a washing tower, which with the Flue gas reacts. The spray falling down is thereby from the Ab sorberturm penetrated from below through the flue gas flowing through. are several absorber stages are arranged in the absorber tower, so the smoke flows through gas the individual absorber stages in succession. In the wash suspension in Oxidation air is blown into the sump at the bottom of the washing tower. The wash suspension is drawn off with pumps and again in the upper section of the Wash tower sprayed. Part of the wash suspension is continuously made up deducted from the swamp and the plaster separated. By adding lime Stone powder and water continuously become a limestone suspension excess maintained.

The absorber stages are formed by spray nozzle levels, so-called headers det. The spray nozzles are each arranged on one level in the wash tower. By the washing liquid is sprayed into the absorber tower, the Overlay the spray cone of the individual nozzles. The absorption zones of this type are relatively ineffective and often do not have sufficient depth so that the throughput of the exhaust gas to be cleaned is limited. A great liquid amount per volume of exhaust gas is necessary to achieve sufficient absorption chen, and thus a high energy requirement for pumping around.

Presentation of the invention

The invention tries to avoid all of these disadvantages. You have the task based, a method and a device for wet flue gas desulfurization development, which is a compact compared to the prior art and have a deeper absorption zone and less demand Washing liquid enables a high throughput of the flue gas to be cleaned lichen. As a result, only a reduced size of the washer is necessary. Of the  Total energy expenditure for flue gas desulfurization as well as the entire Ko most are lowered.

According to the invention, this is the case with a method for wet flue gas removal with the flue gas to be cleaned as the main flow from the bottom to the bottom flows through an absorber tower above and there with a washing solution is removed from a reaction tank and sprayed into the absorber tower, is brought into contact, whereby a gas / drop flow is formed, thereby achieved that evenly distributed over the cross section of the absorber tower ge supply of the flue gas flow and the washing liquid flow takes place, that the average gas velocity is greater than 5 m / s, that in the gas / drop flow is first set a gas velocity, which is greater than the drop speed, causing the drop from the gas stream mung transported upwards or at least held that at finally the relative velocity between the gas flow and the trop fen the washing liquid is reduced to such a value that the drops sink down and finally the wash solution into the reaction tank is returned.

According to the invention, this is the case for a device for flue gas desulfurization achieved according to the preamble of claim 11 in that the feed opening conditions, in particular nozzles, evenly distributed over the cross-section of the minde least one channel are arranged that the at least one channel in Strö direction has a steady or abrupt expansion in cross-section, and that the number of laundry channels connected in parallel is proportional to Cross section of the absorber tower is, with the channels through bounding walls are separated from each other.

The advantages of the invention consist, inter alia, in the fact that in the wet scrubber a "bubble layer" is formed which is largely uniformly distributed over the cross section of the absorber tower and in which strong turbulence prevails. Large drops are broken down into smaller drops by the gas flow. Due to the strong interactions in such a "bubble layer", efficient SO ₂ absorption takes place. This allows a compact absorption zone to be created of a much greater depth than, for. B. by overlapping sprays, as is the current state of the art. The result is that the size of the absorber tower can be reduced. In addition, due to the high gas velocity and the high liquid density, a high throughput through the scrubber is made possible with a simultaneous low requirement for scrubbing liquid per gas volume. In this way, the total energy expenditure is reduced.

It is particularly expedient if the gas speed is 9 m / s. At this velocity becomes the total drop flow from the gas flow carried upwards.

It is also advantageous if additional turbulences are present in the gas / drop flow zen are generated. As a result, the "bubble layer" is created even at a lower level Gas velocity, and it can also be more even, so that even with a larger cross section of the absorber tower, a "spru delschicht ". This can also be done by moving parts against each other flow the "bubble layer" by deflecting and generating swirl in the stream mung done by z. B. the flue gas tangentially laterally into the absorber tower is introduced.

Finally, the one that arises on the walls of the absorber tower is advantageous Liquid film of the washing solution detached and returned to the gas flow becomes. Also, streaks of liquid forming within the gas flow or columns are disassembled and distributed on obstacles. Thereby counteracts the separation of gas and liquid.  

The return of the washing liquid to the reaction tank can be done outside lines arranged in the absorber tower take place or within the absorber tower, preferably over spaces between the laundry channels. It is advantageous if on the underside of the "bubble layer" inside the absorber a controlled amount of the washing liquid is drained.

Advantageous embodiments of the devices according to the invention are in the contain further subclaims. For example, it is useful if at least one obstacle to the gas / drop flow is arranged in the channels net is such. B. turbulence-generating mixing elements, swirl generator or order steering plates. This creates additional turbulence as well as very small drops which even out the flow and the "bubble layer" already lower gas velocity.

With larger cross sections of the absorber tower, it is advantageous if over the Cross section of the washing channel evenly distributed nozzles for introducing the Flue gas and the introduction of the washing liquid are arranged. There This prevents the separation of gas and liquid.

Brief description of the drawing

Several exemplary embodiments of the invention are shown in the drawing.

Show it:

Figure 1 is a schematic representation of an absorber used for wet Rauchgasentschwe felung according to the known state of the art technology.

Fig. 2 shows a schematic longitudinal section of a pilot plant;

Figure 3 is a partial longitudinal section of a laundry channel (test facility) with ge opposing nozzles and sprays directed downward.

Fig. 4 is a diagram of the functional dependence of the pressure differences on the gas velocity;

5 shows a partial longitudinal section of the scrubber channel having opposing nozzles and upwardly directed sprays.

Fig. 6 is a partial longitudinal section of the scrubber channel with a central nozzle and upwardly directed spray;

Fig. 7 is a partial longitudinal section of the scrubber channel having opposing nozzles and in pairs oppositely directed sprays;

Fig. 8 is a partial longitudinal section of the scrubber with a central channel feeding the washing liquid;

. Fig. 9 shows a variant embodiment according to Fig 8 with additional at the Ka nalwand disposed deflection plates;

FIG. 10 is a variant embodiment of FIG 8 with additional turbulenzer generating elements.

FIG. 11 is a variant with a larger channel cross-section;

FIG. 12 is a variant with tangential side flue gas inlet;

Fig. 13 guide a further embodiment with tangential side Rauchgaszu;

Figure 14 channels a variant embodiment having a plurality of parallel-connected scrubber.

Fig. 15 shows a variant embodiment in which the washing liquid in two planes is supplied to the gas stream;

Fig. 16 further embodiments that meet the washing liquid supply be.

Only the elements essential for understanding the invention are shown. The direction of flow of the media is indicated by arrows.  

Way of carrying out the invention

The invention is described in more detail below on the basis of exemplary embodiments and FIGS. 1 to 16.

Fig. 1 shows schematically the structure of a flue gas scrubber according to the known prior art. The flue gas 1 loaded with pollutants flows into the absorber tower 2 and is sprayed there in the flue gas duct 19 with a washing solution 3 , here an aqueous suspension of limestone and gypsum. The aqueous limestone / gypsum suspension 3 is withdrawn from a reaction tank 15 which is charged with limestone 5 and water 6 . It is sprayed into the flue gas 1 via nozzles 13 , which are arranged in various nozzle planes 18 in the absorber tower 2 . A droplet separator 7 is arranged at the absorber outlet and prevents droplet entrainment. After passing the droplet separator 7 , the clean gases 8 are heated in a preheater (not shown here) and led to the chimney. The calcium sulfite primarily formed in the reaction in the absorber is oxidized to gypsum with supplied oxidation air 9 . A portion of the suspension stream is withdrawn from the sump and dewatered so that gypsum 10 with a residual moisture content of less than 10% and waste water 11 are present. The amount of limestone reacted in the reaction with SO ₂ is supplemented in the form of an aqueous limestone suspension, which is removed from a preparation container 4 .

So far, the system described in FIG. 1 has been operated with relatively low gas velocities v _g so that the proportion of the SO ₂ absorbed from the flue gas 1 is also sufficiently large. The inventive method for wet flue gas desulfurization, in which the flue gas 1 to be cleaned flows as main stream from the bottom up through an absorber tower 2 and there with a washing solution 3 , which is removed from a reaction tank 15 and sprayed into the absorber tower 2 , in contact is brought, whereby a gas / drop flow 12 is formed, is now characterized in that distributed over the cross section of the absorber tower 2 , a uniform supply of the smoke gas stream 1 and the scrubbing stream 3 takes place that the average gas velocity v _g greater than 5 m / s is that in the gas / drop flow 12 a gas velocity v _{g is first} set which is greater than the drop velocity v _t , whereby the droplets are transported upwards by the gas flow or at least kept, that the relative velocity between the gas flow 1 and the drops of the washing liquids liquid 3 is reduced to such a value that the drops sink down and that the washing solution 3 is finally returned to the reaction tank.

This creates conditions similar to those in a "bubble area" because the entire drop flow initially carried upward by the gas flow and a gas / liquid flow evenly distributed over the cross section tion with a high liquid density arises, the liquid in itself itself to run back. This leads to excellent absorption conditions.

Fig. 2 shows schematically a pilot plant of the "bubble layer" wet scrubber. The washing liquid 3 is contained in a reaction tank 15 . Above the reaction tank 15 is the vertically arranged scrubber channel 19 in which the laterally introduced flue gas 1 flows from the bottom upwards, where it penetrates a nozzle plane in which a plurality of nozzles 13 are arranged for supplying the washing liquid 3 . In the above-mentioned flow conditions according to the invention, a bubble-like layer is formed, that is to say that the drop flow is carried by the gas flow upwards or at least kept and evenly distributed. There is strong turbulence in the "bubble layer". Large drops are broken down into smaller ones by the gas flow. The intensive interactions between gas 1 and liquid 3 lead to efficient SO ₂ absorption. Due to the high gas velocity and the high liquid density, a high throughput is possible, with only a little washing liquid 3 being required per gas volume. This reduces the total energy expenditure. At the upper end of the washer channel 19 , the cross section of the channel 19 suddenly increases. This leads to a reduction in the relative speed between the gas flow 1 and the liquid drops 3 . The washing liquid 3 collects in the overflow 16 and is returned to the reaction tank 15 via lines 17 .

In another embodiment, not shown, the cross-sectional widening of the channel 19 can also be steadily increasing in the flow direction. An embodiment variant is also possible in which the washing liquid 3 is returned to the reaction tank 15 by draining a controlled amount of the washing liquid from the underside of the "bubble layer".

In Fig. 3, a part of a test channel 19 is shown, in the walls of two opposing nozzles 13 are arranged in this case flat nozzles. The flue gas duct 19 has a rhombic cross section in this embodiment, the cross-sectional area is 0.185 m ² . The flue gas 1 , here air, flows from the bottom up through the channel 19 . The liquid 3 , here water, is sprayed in laterally via the nozzles 13 (390 l / min). The sprays 14 of the two nozzles 13 have an angle of 30 ° to the horizontal. In the state without gas flow, the overlay of the sprays 14 completely fills the channel cross section. The flow of the gas 1 is directed across the spray 14 . As a result of the gas flow, the two opposing sprays 14 are increasingly deflected upwards. When flowing through the spray 14 there is an intensive interaction between the flue gas 1 and the washer fluid 3 and consequently a strong absorption of sulfur dioxide in the area of the sprays 14 . At low gas velocities v _g , most of the liquid 3 flows directly downwards in the form of drops or as a wall film, opposite to the gas flow into the reaction tank 15, not shown here. With increasing gas velocity v _g , droplets are increasingly carried upwards until the entire droplet flow is carried by the gas flow at approx. 9 m / s. In the channel 19 there is a dense and largely evenly distributed water load across the cross section. There is a slip between the entrained water drops and the gas 1 . The speed v _{t of} the ascending drop flow is lower by the relative speed between gas 1 and liquid 3 . The relative speed is necessary to generate the "drag force". The strong turbulence in the "bubble layer" enables the formation of this layer in the first place. In principle, the water in the flow has the opportunity to collect and work downwards in the form of strands or water columns or as a wall flow against the gas flow. The effect of the gas flow is strong enough at the appropriate speed to at least dissolve the strands or water columns.

In another variant, the channel 19 has a circular cross section. This is cheaper than a square cross-section, because "sneackage effects" can easily occur in the corners.

The pressure p was measured at the points marked p1, p2 and p3 in FIG. 3. The first measuring point is located at the inlet of the channel 19 , the second measuring point is located immediately after the spray 14 , and the third measuring point is at the outlet of the channel 19 . The dependence of the pressure differences on the gas velocity v _g is shown in Fig. 4. Δp3 represents the pressure difference across the spray, while Δp2 represents the pressure difference of the channel. The measurements show that the gas pressure drop across the "spray layer" is relatively small.

The formation of the "bubble layer" is largely independent of which one Kind the liquid phase is brought into the gas flow.

FIGS. 5 and 6 show the application of flat nozzles or swirl nozzles. The spray 14 of the nozzles 13 can be directed upwards as shown in FIGS. 5 and 6, but it can also be directed downwards.

In Fig. 7 a variant is shown in which a good absorption capacity is achieved even at low gas flow rates with a low pressure drop across the nozzle zone of the washing liquid 3 . In this exemplary embodiment, the nozzles 13 of a nozzle plane 18 are spaced apart from one another with their nozzle openings in such a way that, during operation of the nozzles 13, pairs of opposing sprays 14 are formed which meet one another and which are connected to adjacent, likewise oppositely directed sprays 14 (in FIG. 7 form invisible) spray lane, the longitudinal direction of said spray lanes being perpendicular to the flow direction of the flue gas 1 and spaces between the spray lanes through which the flue gas 1 flows.

Depending on the diameter of the channel 19 , a plurality of nozzles 13 can be arranged distributed across the cross section. The nozzles 13 can also be arranged in several nozzle levels 18 one above the other.

FIG. 8 shows a preferred embodiment variant in which, in contrast to the variant described in FIG. 1, the liquid phase 3 is supplied from below in the form of a jet in the middle of the channel 19 . A baffle plate 20 ensures a radial distribution of the liquid 3 . The pressure at the outlet only needs to be a few meters "head".

Fig. 9 differs from Fig. 8 only in that additionally inclined sheets 21 are arranged on the channel wall. These can be provided at one or more points. The liquid film forming on the walls is only partially taken along by the gas flow. The downloadable part is directed by the sheets 21 into the channel 19 so that it can then be more easily detected by the upward gas flow.

In another embodiment variant, not shown, are across cut the "bubble layer" distributed obstacles that serve to that any liquid strands or columns of liquid that form are dissolved and thus there is no separation of gas and liquid.

8 to Fig. 10 differs from FIG. Only in that additional flow in the gas / droplet 12 is a turbulence-generating mixing element 22, in this case a against the gas / droplet stream 12 directed obliquely positioned dreieckför Miges sheet. With the help of the elements 22 , very small droplets are also generated. The impinging liquid 3 is scattered there and the adhering remainder is torn off by the flow, in particular at the edges in the form of small drops.

Fig. 11 shows a variant embodiment in which the washer channel 19 has a relatively large cross-section. There arises in comparison to the embodiment according to FIG. 8, the risk of separation of flue gas 1 and liquid 3 . In order to prevent this, or at least to delay its formation, the gas 1 is fed into the channel 19 uniformly over the cross section. This is done at the entry of the channel 19 Rauchgasdü sen 23 , which are evenly distributed over the cross section. A perforated plate could also be used for this, but this would lead to a greater pressure drop. The pressure drop across nozzles is lower if the diverging outlet is designed to be optimal for the recovery of pressure.

Fig. 12 and Fig. 13 show variants in which the flue gas 1 tan potential is laterally supplied to the channel 19 . This creates a swirl 24 in the "bubble layer". It is known from fluid mechanics that with suitable dimensioning the swirl 24 disintegrates in the longitudinal flow and causes additional turbulence. If several channels connected in parallel are used (see FIG. 14), then it is advantageous if the directions of the swirl movement in the individual channels 19 are selected such that the sum of the swirl 24 results in zero.

While in FIG. 12 the liquid 3 introduced into the center of the channel 19 strikes the baffle plate 20 and disintegrates into small drops, in the variant shown in FIG. 13 the liquid is introduced into the core of the swirl movement. Due to the swirl 24 (radial speed gradient), the liquid speed 3 spreads quickly over the cross section and there are also small drops effective for the absorption of the SO ₂ . In addition, small drops tend to be in the center of the channel 19 and diffuse outward from this reservoir.

All of the above Measures that additional turbulence as well as small drops testify and thus a "bubble layer" even with a comparatively smaller Gassing gas velocity are also suitable for larger ones Channel cross sections to create a "bubble layer".

If the channel cross-section becomes even larger, e.g. B. in the industrially used absorber towers for flue gas desulfurization, then it is, if appropriate, advantageous to connect several channels 19 in parallel to counteract the separation of gas and liquid.

Fig. 14 shows a corresponding embodiment in which a plurality of channels are collected 19 simultaneously with the flue gas 1, and liquid 3 be charged and thus each have a "hot layer" is created within the channels by using a sufficient gas velocities. At the upper end of the channels 19 deflection / baffle plates 20 are arranged, which allow partial flows of the drop flow to arise. The collision of these partial streams creates additional small drops which are effective for SO ₂ absorption. A further advantage of this variant shown in FIG. 14 is that the free spaces between the cylindrical channels 19 ( not visible in FIG. 14) can also be used to direct the washing liquid 3 back into the reaction tank 15 .

A further embodiment variant is shown in FIG . It differs from the embodiment shown in FIG. 8 only in that the washing liquid 3 is injected into the flue gas stream flowing along the channel 19 not in one but in two planes 18 . Of course, it is also possible in other design variants to use more than two nozzle levels 18 .

In Fig. 16 different ways of introducing the washing solution 3 into the flue gas stream 1 are shown again. In case a, a free upper surface 25 forms , above which the "bubble layer" formed from the rising gas / drop flow is formed. In case b the "bubble layer" is immediately available, in case c "dead" areas 26 are again formed without "bubble layer". The washing liquid 3 collects in the interior of the plates 22 acting as hin for the flow and can then be returned via lines 17 to the reaction tank 15 .

Of course, the invention is not limited to the execution examples described here. For example, the "openings" for the smoke gas 1 can penetrate the reaction tank 15 , so that there is a coherent reaction tank 15 .

The solution according to the invention, in which a layer similar to a "bubble layer" is generated for flue gas desulfurization, is characterized in particular by the fact that smaller washers and thus pumps of lower power and size can be used so that more effective SO ₂ absorption occurs and this results in lower investment and operating costs.

Reference list

1

Flue gas

2nd

Absorber tower

3rd

Washing solution

4th

Absorber tank

5

limestone

6

water

7

Droplet separator

8th

Clean gas

9

air

10th

plaster

11

sewage

12th

Gas / drop flow

13

Feed openings for pos.

3rd

14

spray

15

Reaction tank

16

Overflow

17th

Lines to pos.

15

18th

Nozzle plane

19th

Flue gas duct

20th

Baffle

21

Sheets on the canal wall

22

turbulence generating element

23

Nozzles for pos.

1

24th

Swirl

25th

free surface

26

Areas without a "bubble layer"
p pressure
v _g

Gas velocity
v _t

Drop speed

Claims (20)

1. Process for wet flue gas desulfurization, in which the flue gas to be cleaned ( 1 ) flows as the main flow from the bottom up through a sorber tower ( 2 ) and there with a washing solution ( 3 ), which is removed from a reaction tank ( 15 ) and in the absorber tower (2) is sprayed, is brought into contact, wherein a gas / droplet stream (12) is formed, characterized in that distributed over the cross-section of the absorber tower (2) a uniform supply of the flue gas stream (1) and the Wash liquid flow ( 3 ) takes place that the mean re gas speed (v _g ) is greater than 5 m / s, that in the gas / drop flow ( 12 ) a gas speed (v _g ) is first set, which is greater than the drop speed (v _t ), as a result of which the drops are transported upward by the gas flow ( 1 ) or at least kept at least that the relative speed between the gas flow ( 1 ) and the drops of the washing liquid ( 3 ) are reduced to such a value that the drops sink down and that finally the washing solution ( 3 ) is returned to the reaction tank ( 15 ). 2. The method according to claim 1, characterized in that the average gas velocity (v _g ) is greater than 9 m / s. 3. The method according to claim 1 or 2, characterized in that turbulence is generated in the gas / drop flow ( 12 ). 4. The method according to claim 1 or 2, characterized in that the Drop flow is diverted. 5. The method according to any one of claims 1 to 4, characterized in that a liquid on the walls of the absorber tower ( 2 ) emerging liquid film is removed and returned to the gas flow. 6. The method according to any one of claims 1 to 4, characterized in that in the gas / drop flow ( 12 ) forming streaks of liquid on the inside of the absorber tower ( 2 ) arranged obstacles resolved and distributed. 7. The method according to any one of claims 1 to 6, characterized in that the flue gas ( 1 ) is guided tangentially laterally into the absorber tower ( 2 ). 8. The method according to any one of claims 1 to 7, characterized in that the washing liquid ( 3 ) collected in an overflow ( 16 ) and at closing via lines outside the absorber tower ( 2 ) arranged lines ( 17 ) in the reaction tank ( 15 ) returned becomes. 9. The method according to any one of claims 1 to 7, characterized in that the washing liquid ( 3 ) within the absorber tower ( 2 ), preferably as between spaces between the washing channels ( 19 ), is returned to the reaction tank ( 15 ). 10. The method according to any one of claims 1 to 7, characterized in that the washing liquid ( 3 ) within the absorber tower ( 2 ) from the underside of the "bubble layer" is returned to the reaction tank ( 15 ). 11. Device for performing the method according to claim 1, in wesent union consisting of a reaction tank ( 15 ) and an absorber tower ( 2 ) with at least one scrubber duct ( 19 ) and with therein in at least one plane ( 18 ) arranged feed openings ( 13 ) for Spraying a washing solution ( 3 ) into the flue gas stream ( 1 ), characterized in that the feed openings ( 13 ), preferably nozzles, are evenly distributed over the cross section of the at least one scrubber duct ( 19 ), that the at least one scrubber duct ( 19th ) has a continuous or abrupt cross-sectional expansion in the direction of flow, and that the number of channels ( 19 ) connected in parallel is proportional to the cross section of the absorber tower ( 2 ), the channels ( 19 ) being separated from one another by walls ( 25 ). 12. The device according to claim 11, characterized in that the channels ( 19 ) have a circular cross section. 13. Device according to one of claims 11 or 12, characterized in that in the channels ( 19 ) at least one obstacle for the gas / drop fenströmung ( 12 ) is arranged. 14. Device according to claim 13, characterized in that a turbulence-generating mixing element ( 22 ), preferably an obliquely placed triangular sheet, is arranged as an obstacle. 15. The device according to claim 13, characterized in that as an obstacle a means for deflecting the drop flow are arranged. 16. The device according to claim 13, characterized in that as an obstacle means for detaching the liquid film, preferably inclined te plates ( 21 ), is arranged on the wall of the channel ( 19 ). 17. The device according to claim 13, characterized in that as an obstacle a means for dissolving the strand of liquid is arranged. 18. Device according to one of claims 11 to 17, characterized in that at the entry into the at least one channel ( 19 ) uniformly distributed across the cross section nozzles ( 23 ) for introducing the flue gas ( 1 ) are arranged. 19. Device according to one of claims 11 to 17, characterized in that a perforated plate for the introduction of the flue gas ( 1 ) is arranged at the entry into the at least one channel ( 19 ). 20. Device according to one of claims 11 to 19, characterized in that the spray nozzles ( 18 ) are arranged uniformly distributed over the cross section of the at least one channel ( 19 ).