A scrubber for the treatment of flue gases

Description

The description is 12 pages long (including 3 pages of illustrations). 3o Figure 2 HU 226 494 Β1 characterized in that the gas scrubber (230) is in countercurrent connection between the gas flow and the liquid flow in several stages, and which includes: a) a horizontal chamber (218) with a substantially rectangular cross-section, vertically exhausting dehumidifier (209) covering the entire vertical cross-section; b) a sloping, shallow liquid collection tray (216) in each compartment (210, 211, 212, 214); c) a pump (217) that distributes the liquid from each trough at a controlled flow rate to a series of spray nozzles (205) in the same compartment (210, 211, 212, 214) - forming 3-5 vertical curtains around the gas flow and covering the entire vertical cross-section, while the liquid droplets fall back into the trough (216); d) the liquid sumps (216) of the different compartments (210, 211, 212, 214) are inclined, a process liquid overflow is formed from the compartments (214, 212, 211) into the previous one (212, 211, 210), without the possibility of liquid backflow; a process liquid overflow is formed from the sump (16) of the first compartment (210) into a collecting tank (219); a liquid inlet is formed in the last compartment (214); e) the gases are introduced at a gas inlet (200) on one side and discharged at a gas outlet (208) on the other side. The invention also provides a process for wet gas scrubbing for treating exhaust gases from power plants or chemical plants, which absorbs objectionable acidic pollutants such as SO2, SO3, HCl, nitrogen oxides, CO2 and the like into an aqueous solution without settling solids, and comprises the following steps: - in the gas scrubber (230), a gas flow and a liquid flow are conducted in countercurrent connection in several stages; - the gases are introduced through a gas inlet (200) on one side, passed through each compartment (210, 211, 212, 214) and discharged through a gas outlet (208) on the other side; - the gases are conducted in a horizontal chamber (218) which is divided into compartments (210, 211, 212, 214) along a horizontal axis; - process fluid is conducted in an inclined, shallow fluid collection pan (216) in each compartment (210, 211, 212, 214) against the gas flow; - distributing the liquid from each trough (216) with a pump (217) at a controlled flow rate to a series of spray nozzles (205) in the same compartment (210, 211, 212, 214), forming 3-5 vertical curtains around the gas flow and covering the entire vertical cross-section, and collecting the liquid droplets after falling back into the trough (216); - the process fluid is led from the compartments (214, 212, 211) to the previous one (212, 211, 210) through process fluid overflows, without the possibility of fluid backflow; - the process liquid is led from the sump (16) of the first compartment (210) to a collection tank (219) via a process liquid overflow, the process liquid is led to the last compartment (214) via a liquid inlet; - the gases are dehumidified in the last compartment (214); - the gas flow is quenched with water vapor and thermally equalized in the different compartments (210, 211, 212, 214) in which liquid of different controlled concentrations is stored, creating a true multi-stage countercurrent process design; - if cooling of the exhaust gases is required - to limit the plume effect - water from an integrated cooling tower (204) is used in the last compartment and recycled to the cooling tower (204) from any intermediate compartment (212); and - the dehumidification is preferably carried out by dehumidifiers (31), which consist of three, four or five 31 "stakes" from the top to the bottom of the chamber (218), each "stake" (31) being made of sheet metal, bent at an angle, open opposite to the flow direction (32), thus distributing the gas flow lines evenly over the entire cross-sectional area and minimizing the entrapment of droplets between the compartments. This invention is a gas scrubber for wet treatment of exhaust gases from power plants or chemical plants, which absorbs objectionable acidic pollutants such as SO2, SO3, HCl, nitrogen oxides, CO2 and the like into a water-based solution without settling solids, having a horizontal chamber, where the chamber is divided into compartments, which have a liquid collection tray, spray nozzles, and a pump for pumping liquid into the spray nozzles. Furthermore, we provide a process for gas scrubbing, wet gas scrubbing for treating exhaust gases from power plants or chemical plants, which absorbs objectionable acidic pollutants such as SO2, SO3, HCI, nitrogen oxides, CO2 and the like into a water-based solution without settling solids, which has a horizontal chamber, where the chamber is divided into compartments, which have a liquid collection pan, a spray nozzle, a pump for pumping the liquid into the spray nozzles. Flue gases from power plants and boiler houses contain varying amounts of SO2, SO3, nitrogen oxides or acids and similar acidic pollutants derived from the fuel burned. Similarly, the exhaust gases from many chemical plants contain these or similar compounds as pollutants. These pollutants are a threat to the environment2 EN 226 494 Β1 sec, and legal measures usually require the treatment of these gases before they are released into the atmosphere to reduce the amount of these pollutants as much as possible. In some cases, CO2 also falls into this category. Many processes and methods are used, which are generally classified as wet flue gas desulfurization (FGD), which include the following steps: contact with an aqueous solution or suspension that has a basic reaction to absorb the contaminants of concern. These processes and methods can be divided into the following subgroups: (a) an alkaline suspension containing limestone or quicklime, resulting in a slurry of calcium sulfite or sulfate crystals and a mixture of contaminated aqueous solution; b) alkaline solutions of hydroxides of alkali metals (potassium, sodium), alkaline earth metals (calcium, magnesium), and ammonium groups, which yield sulphite or sulphate salts in which solids are not significantly precipitated; c) dilute saline solutions, such as seawater, on a single-use basis. Direct contact between the flue gases and the suspension or solution is required for the absorption of acidic contaminants into an aqueous solution and the reaction of a basic reacting component. Such contact occurs in specially designed devices called contactors, absorbers or scrubbers. The term scrubber is used throughout this description. Conventional industrial scrubbers generally consist of vertical columns in which the sludge or solution flows downwards and the gases flow either downwards (this is a unidirectional connection) or upwards (this is a countercurrent connection). In smaller operations, packed towers or plates have been used in the past, but today countercurrent spray towers are widely used. These cannot handle concentrated sludge, are much more expensive to build, and require higher pressures to operate the gas flow. Industrial scrubbers have to meet contradictory requirements. On the one hand, the liquid / gas flow rate must be controlled, kept within an operational range, with significant internal recirculation, and on the other hand, a very small amount of liquid must be moved for further processing of the concentrated solution. A conventional, standard countercurrent spray tower generally consists of an empty vertical cylindrical chamber as shown in Figure 1 using the following process steps: a) The solution or slurry is pumped under pressure and sprayed into the upper part by means of a large number of spray nozzles, organised in a multiple system covering the entire horizontal cross-section of the column, at one or more different heights. b) The resulting droplets flow downwards, most of the droplets collide with each other in the air and coalesce into larger droplets. c) The gases are introduced through a horizontal line on one side of the tower and their flow lines must describe a 90° curve before flowing vertically upwards against the droplet flow, resulting in uneven velocities and dead spaces. d) Vertical contact results in partial absorption and temperature equilibrium as the gases can cool down through water evaporation. Sometimes small droplets can be carried upwards with the rising gas stream. e) Above the upper spray nozzle row, the gases are usually de-emulsified from entrained droplets before being discharged. f) Most of the solution or sludge is pumped back from the sump to the spray nozzles and fresh solution or suspension is added to the stream. As a result, the solution or sludge mixture is continuously removed from the sump and sent to the next process step, which is an integral and necessary part of any FGD process. This generally accepted design of the prior art spray tower scrubber has been used in a large number of FGD plants producing calcium sulfite or sulfate sludge because it is simple and can be operated with more or less sludge. However, it has inherent shortcomings that make it unsuitable for efficient use in other processes. Typical prior art examples include: a) The scrubber operates with a single steady state most of the time, since the large liquid recirculation flow is of the end-to-end type and the concentration changes in the liquid circuit are relatively small. Any process that requires more than one steady state (in order to obtain a lower residual concentration of objectionable substances in the exhaust gases) cannot be implemented in a single spray tower scrubber. The countercurrent terminology here is misleading, as it refers only to the hydrodynamic flow, but not to the process result. Furthermore, to approach a single state equilibrium and provide the required mass flow, the circulation load must be significantly increased and excess reactants must be maintained, which leads to waste of unused reagents in the effluent. b) Relatively low gas velocities, generally less than 1-3 m / s, are used to limit back-mixing, the entrainment of liquid / suspension droplets, which can be counterproductive in the absorption process. Lower gas velocities, together with high volumetric flow rates of the flue gases, lead to large diameter industrial columns. c) These large diameters, together with the significant heights for different tasks (i.e. sludge collection, gas reversal section, separation and dehumidification) result in very bulky columns, with expensive construction and foundation problems. d) These significant heights increase the pumping energy required to circulate the suspension and require more expensive high-pressure pumps. Document US 5403568 describes a horizontal scrubber for removing sulfur dioxide from a gas stream. HU 226 494 Β1 for the destruction of. The gases travel in a horizontal housing and there is at least one vertical, multiple liquid injection. US 4343771 describes a horizontal cross-flow scrubber that can increase removal efficiency by reducing the interacting spray density by using minimum critical nozzles. US 3948608 discloses a device for cleaning sulfur dioxide and other polluting gases. The gases flow through a horizontal housing and are sprayed. The resulting sludge is washed from the floor into sludge tanks by the spray. However, the above solutions did not eliminate the relatively low flow rate, the difficulties associated with handling settled materials, the relatively large space requirement, and the somewhat difficult installation options. The object of the present invention is to overcome the above disadvantages and to provide a new, more efficient scrubber which avoids or at least significantly reduces the inherent disadvantages of spray scrubbers and is particularly suitable for FGD processes, aiming at high removal efficiency, using an aqueous solution in which the solids are substantially not settled. The preferred reagent for the process is the basic reagent ammonia, since these yield concentrated ammonium sulfate solutions which can be profitably processed into various fertilizers. The device according to the invention is a gas scrubber, for wet treatment of exhaust gases from power plants or chemical plants, which absorbs objectionable acidic pollutants such as SO2, SO3, HCl, nitrogen oxides, CO2 and the like into a water-based solution, without settling solids, which has a horizontal chamber, where the chamber is divided into compartments, which have a liquid collection tray, spray nozzles, a pump for pumping liquid into the spray nozzles, characterized in that the gas scrubber gas flow and liquid flow are in countercurrent connection in several stages, and which includes: (a) a horizontal chamber with a substantially rectangular cross-section and a vertically exhausting dehumidifier covering the entire vertical cross-section; (b) a sloping, shallow liquid collection tray in each compartment; c) a pump that distributes the liquid from each trough, with a controlled flow rate, to a series of spray nozzles in the same compartment, forming 3-5 vertical curtains around the gas flow, covering the entire vertical cross-section, while the liquid droplets fall back into the trough; d) the liquid sumps of the different compartments are inclined, a process liquid overflow is formed from the compartment mains into the previous one, without the possibility of liquid backflow; a process liquid overflow is formed from the sump of the first compartment into a collection tank; there is a liquid inlet in the last compartment; e) the gases are introduced at the gas inlet on one side and discharged at the gas outlet on the other side. According to one aspect of the scrubber of the invention, the horizontal axis of the apparatus is bent or reversed in any direction or is arranged in a circular or horseshoe shape in the available space. In another aspect, the dehumidifiers between the compartments are of a "picket fence" arrangement and ensure a uniform distribution of flow lines in the initial gas flow direction throughout the vertical cross section, thereby minimizing droplet transfer between the compartments; the number of compartments may be between 3 and 7. According to the invention, the average linear gas velocity along the chamber is in the range of 3-12 m / s, and chilled water from the integrated cooling tower circuit is introduced into the last compartment and is returned to the cooling tower for recycling from any intermediate compartment. Furthermore, solutions of increasing concentration are obtained from the overflows of the various compartments, and finally a concentrated final liquid is obtained in the sump of the first compartment. Furthermore, the addition of the reactant is controlled by continuous analysis of the solution in one of the intermediate compartments with feedback, and basic reactants 206, 207 are introduced into either compartment. The reactant is distributed between several compartments or sprayed into the hot gases. The gas scrubber device according to the invention avoids or at least significantly reduces the shortcomings of the prior art solutions, which have been listed above, in light of the following: It allows for a true multi-stage countercurrent process configuration instead of a single stage, with separate internal recirculation to control the liquid / gas flow rate over the operating range and requiring a very small net forward liquid flow to provide a concentrated solution for further processing. a) This results in the following: - a smaller contact volume is required due to the higher mass flow driving forces, and / or - we obtain a higher concentration of the mixture solution for further processing, - a lower residual concentration of objectionable pollutants remains in the exhaust gases. b) It allows much higher gas velocities because the gas flows in a circular pattern relative to the gravitational force around the droplets, so that the droplet trajectory can only move sideways as it collides with the vertical picket fence-like dehumidifiers. This results in much smaller cross-sectional areas and radial dimensions. c) The horizontal arrangement allows for lightweight construction, with any suitable height, and is easily adaptable to industrial layouts as it can be bent and installed on the roof or at roof level. The required troughs are very shallow and can be tilted in any suitable direction. HU 226 494 B1 d) The required pump head is lower, at least five times, so energy costs are greatly reduced and the pumps do not need to be of the high-pressure type. e) The separation of solutions in different compartments allows for feedback control of the input of reagents to effectively control fluctuations in operating conditions and consequently minimize the use and loss of such reagents. The invention will be described below with reference to Figures 2 and 3. Brief description of the drawings Figure 1: Schematic representation of a typical prior art spray tower scrubber; Figure 2: schematic representation of the gas scrubber device according to the invention; Figure 3: shows the cross-section of the dehumidifier of the picket fence according to the invention. Detailed description of the drawings Figure 1 shows a prior art spray tower with a dehumidifier 14, a sprayer 15, a trough 16, a reagent inlet 10, and a gas inlet 11. Referring to Figure 2, a novel scrubber 230 of the invention is shown, which consists of a horizontal empty chamber 218 with a rectangular cross-section divided along the horizontal axis into a plurality of compartments 210, 211, 212, 214 with "picket fence"-like (31) dehumidifiers. The flue gases enter at one end 200, pass through each of the compartments 210, 211, 212, 214, and exit through a conduit at the other end 208. The last compartment 214 also serves as a final dehumidifier location before the gases exit. The compartments are indexed in the direction of gas flow. The picket fence dehumidifiers 31 consist of three, four or five pickets 31 from the top to the bottom of the chamber 218, each picket 31 being made of sheet metal bent at an angle and open against the flow direction 32, as shown in Figure 3. The function of the picket fence dehumidifiers 31 205 is to spread the gas flow lines evenly over the entire cross-sectional area and to minimize droplet entrainment between compartments. Although the "picket fence" type dehumidifiers 205 are effective and produce low pressure droplets, other types of dehumidifiers can be used, such as perforated plates, screen wires or rods, louvers, and the like. If necessary due to design constraints or suitability, the horizontal axis can be bent or rotated in any direction, or even complete turns can be formed in a circular or horseshoe shape. At the bottom of each compartment is a liquid sump 216 which feeds a centrifugal pump 217 (possibly with the exception of the last compartment) which distributes the liquid to a series of spray nozzles 205 which form three to five curtains circularly relative to the gas flow. In this way the circulation rate can be fixed in each compartment 210, 211, 212, 214 independently of the others. The liquid droplets are collected back into the sump 216 in the same compartment 210, 211, 212. The base reagent 206, 207 can be introduced into any compartment or distributed to several compartments or sprayed into the hot flue gases 201 entering the system. The process water or process liquid is introduced into the last compartment 214. The number of compartments can be chosen depending on the procedure in question. The gas flow is quenched with water vapor and equilibrated thermally in the various compartments 210, 211, 212, 214, which contain different controlled concentrations of liquid, forming a true multi-stage countercurrent process design. The liquid sumps 216 of the various compartments are arranged so that excess liquid overflows from one compartment to the previous one, without the possibility of liquid backflow. Solutions of increasing concentration are obtained from the overflows of the various compartments, and the concentrated solution is obtained from the sump of the first compartment, which overflows into the collection tank 219 (the liquid outlet of the gas scrubber). If necessary, water can be used to cool the exhaust gases to limit the tube effect from an integrated cooling tower 204 in the last compartment. The method according to the invention is suitable for treating the exhaust gases of power plants or chemical plants, in which acidic pollutants such as SO2, SO3, HCI, nitrogen oxides, CO2 and the like are dissolved in a water-based solution, without settling solids. The apparatus used in the method has: a chamber 218, where the chamber 218 is divided into compartments 210, 211, 212, 214, which have a liquid collecting tray 216, a spray nozzle 205, a pump 217 for pumping the liquid into the spray nozzles 205. It consists of the following steps: - in the gas scrubber 230, a gas stream and a liquid stream are conducted in countercurrent connection in several stages; - the gases are introduced through the gas inlet 200 on one side, passed through each of the compartments 210, 211, 212, 214, and discharged through the gas outlet 208 on the other side; - the gases are conducted in a horizontal chamber 218, which is divided along a horizontal axis into compartments 210, 211, 212, 214; - process fluid is conducted in an inclined, shallow fluid collection pan 216 in each compartment 210, 211, 212, 214 against the gas flow; - Using a pump 217, we distribute the liquid from each of the 216 troughs, with a controlled flow rate, to a series of 205 spray nozzles in the same 210, 211, 212, 214 compartments, forming 3-5 vertical curtains around the gas flow, covering the entire vertical HU 226 494 cross section Β1, and the liquid drops are collected in the trough 216 after falling back; - the process fluid is led from the compartments 214, 212, 211 to the previous one (212, 211, 210) through process fluid overflows, without the possibility of fluid backflow; - the process liquid from the sump 216 of the first compartment 210 is led through a process liquid overflow into a collection tank 219; the process liquid is led through a liquid inlet into the last compartment 214; - in the last compartment 214, the gases are dehumidified; - the gas flow is quenched with water vapor and equalized thermally in the different compartments 210, 211, 212, 214, in which liquid of different controlled concentrations is stored, creating a true multi-stage countercurrent process design; - if cooling of the exhaust gases is required - to limit the plume effect - water from an integrated cooling tower 204 is used in the last compartment and reused for the cooling tower 204 from any of the intermediate compartments 212; and - dehumidification is preferably carried out by means of dehumidifiers 31, which consist of three, four or five “stakes” 31 from the top to the bottom of the chamber 218, each “stake” being made of a plate 31, bent at an angle, open against the direction of flow 32, thus distributing the gas flow lines evenly over the entire cross-sectional area and minimizing the entrapment of droplets between the compartments. The process is characterized by an average linear gas velocity along the chamber 218 in the range of 3-12 m / s. The process is characterized by introducing chilled water from an integrated cooling tower circuit 204 into the final compartment 214 and returning it to the cooling tower 204 from any of the intermediate compartments 212 for recycling. In the process, solutions of increasing concentration are obtained from the overflows of the different compartments 210, 211, 212, 214, and finally a concentrated final liquid is obtained in the sump 216 of the first compartment 210. In the process, gases are contacted with liquids of controlled concentration in a series of compartments 210, 211, 212, 214. In one embodiment of the method, the addition of reactants 206, 207 is controlled by continuous feedback analysis of the solution in one of the intermediate compartments 212. In another embodiment, a basic reactant 206, 207 is introduced into any of the compartments 210, 211, 212, 214. In another embodiment of the method, the basic reactant 206, 207 is distributed among several compartments 210, 211, 212, 214, or is sprayed into the hot gases 201 inlet. In summary: the invention is based on the following elements, which significantly reduce the shortcomings of the prior art solutions: a) The separate compartments allow for a true multi-stage countercurrent process configuration with higher mass flow driving force, instead of a single stage, with separate internal liquid recirculation to control the liquid / gas volume flow rate over the operating range and requiring a very small net forward liquid flow to provide a concentrated solution for further processing. This results in a smaller contact volume being required for the process and / or a higher concentration of the mixed solution being obtained for further processing and / or a lower residual concentration of objectionable pollutants remaining in the exhaust gases. b) The vertical arrangement allows much higher gas velocities in the spray tower, as the gas flows in a circular manner relative to the gravitational force around the droplets, so that the droplet trajectory can only move parabolically sideways until it hits the vertical picket fence-like dehumidifiers. This results in much smaller cross-sectional areas and radial dimensions and overall volume. c) The new layout allows for lightweight construction, with any suitable height, and can be easily adapted to industrial layouts without functional compromises, as it can be bent and installed on the roof or at roof level. The required troughs are very shallow and can be tilted in any suitable direction. d) The required pump head is lower, at least five times, so energy costs are greatly reduced and the pumps do not need to be of the high-pressure type. The invention will be described in the following with reference to some preferred embodiments, however, the invention is not limited to these embodiments, but rather covers all equivalents, modifications and variations, so the following examples illustrate preferred embodiments of the invention. In the following examples, percentages are by weight unless otherwise indicated. Example 1 Flue gas at 100°C at a flow rate of 400,000 Nm3 / h, with a chamber flow velocity of 3-12 m / s, containing 2360 ppm (by volume) SO2 and 10% water (by volume), is introduced into a 5-compartment scrubber according to the invention. 9500 kg / h of 15% ammonia solution is mixed into the inlet line, which cools the gases to 64°C. Cooling water at 28°C is added to the last compartment, and the outlet gases are cooled to 40°C and contain less than 1% SO2 in the feed and less than 10 ppm (by volume) ammonia. The water is removed from the second compartment and returned to an integrated cooling tower for reuse, except for a very small flow6 HU 226 494 Β1 lake, which overflows into the first compartment. 4980 kg / h of 30% ammonium sulfite is obtained from the first compartment at 54 °C. Example 2 Flue gas at 150°C at a flow rate of 750,000 Nm3 / h, with a chamber flow velocity of 3-12 m / s, containing 745 ppm (by volume) SO2 and 10% water (by volume), is introduced into a 4-compartment scrubber according to the invention. 5600 kg / h of 15% ammonia solution is sprayed and evaporated in the inlet line, which cools the gases to 139°C. Cooling water at 28°C is added to the last compartment, and the outlet gases are cooled to 40°C and contain less than 3% SO2 in the feed and less than 10 ppm (by volume) ammonia. Water is removed from the second compartment and returned to an integrated cooling tower for reuse, apart from a very small stream that overflows into the first compartment. Example 3 Flue gas at 150°C with a flow rate of 1750,000 Nm3 / h, a chamber flow velocity of 3-12 m / s, containing 1000 ppm (by volume) SO2 and 10% water (by volume), is introduced into a 6-compartment scrubber according to the invention. 17,700 kg / h of 15% ammonia solution is sprayed in and evaporated in the inlet line, which cools the gases to 135°C. The resulting solution overflows from the first compartment at 72°C, which contains 4980 kg / h of 30% ammonium sulfite. Cooling water at 28°C is fed into the last compartment and the outlet gases are cooled to 40°C and contain less than 1.5% SO2 in the feed and less than 10 ppm (by volume) ammonia. Water is removed from the second compartment into the chamber and returned to an integrated cooling tower for reuse, apart from a very small stream which overflows into the first compartment.

Claims

PATENT CLAIMS 1. A gas scrubber (230) for wet treatment of exhaust gas from power plants or chemical plants, which absorbs objectionable acidic pollutants such as SO2, SO3, HCI, nitrogen oxides, CO2 and the like into an aqueous solution without settling solids, having a horizontal chamber (218), wherein the chamber (218) is divided into compartments (210, 211, 212, 214) having a liquid collection pan (216), a spray nozzle (205), a pump (217) for pumping liquid into the spray nozzles (205), characterized in that the gas scrubber (230) is in countercurrent connection with a gas stream and a liquid stream in multiple stages, and comprising: a) a horizontal chamber (218) with a substantially rectangular cross-section, vertically exhausting dehumidifier (209) covering the entire vertical cross-section; b) an inclined, shallow liquid collection tray (216) in each compartment (210, 211, 212, 214);c) a pump (217) which distributes the liquid from each tray, with a controlled flow rate, to a series of spray nozzles (205) in the same compartment (210, 211, 212, 214) - forming 3-5 vertical curtains around the gas flow and covering the entire vertical cross-section, while the liquid droplets fall back into the tray (216); d) the liquid trays (216) of the different compartments (210, 211, 212, 214) are inclined, a process liquid overflow is formed from the compartments (214, 212, 211) into the previous one (212, 211, 210), without the possibility of liquid backflow; a process fluid overflow is formed from the sump (16) of the first compartment (210) into a collection tank (219); a fluid inlet is provided in the last compartment (214); e) the gases are introduced at a gas inlet (200) on one side and discharged at a gas outlet (208) on the other side; 2. A gas scrubber (230) according to claim 1, characterized in that its horizontal axis is bent or reversed in any direction or is arranged in a circular or horseshoe shape in the available space.

3. A gas scrubber (230) according to claim 1, characterized in that the dehumidifiers between the compartments are arranged in a "picket fence" (31) arrangement and ensure a uniform distribution of flow lines in the initial gas flow direction (32) throughout the entire vertical cross-section, and droplet carryover between the compartments (210, 211, 212, 214) is reduced to a minimum.

4. The scrubber (230) of claim 1, wherein the number of compartments (210, 211, 212, 214) is between three and seven.

5. A method for wet gas scrubbing for treating exhaust gases from power plants or chemical plants, for absorbing acidic pollutants such as SO2, SO3, HCl, nitrogen oxides, CO2 and the like into an aqueous solution, without settling solids, characterized in that it comprises the following steps: - in the gas scrubber (230), the gas flow and the liquid flow are conducted in countercurrent connection in several stages; - the gases are introduced through a gas inlet (200) on one side, passed through each compartment (210, 211, 212, 214) and discharged through a gas outlet (208) on the other side; - the gases are passed through a horizontal chamber (218) which is divided into compartments (210, 211, 212, 214) along a horizontal axis; - process fluid is conducted in an inclined, shallow fluid collection pan (216) in each compartment (210, 211, 212, 214) against the gas flow;- distributing the liquid from each trough (216) with a controlled flow rate to a series of spray nozzles (205) in the same compartment (210, 211, 212, HU 226 494 Β1 214) by means of a pump (217), forming 3-5 vertical curtains around the gas flow, covering the entire vertical cross-section and collecting the liquid droplets after falling back into the trough (216); the process liquid is led from the compartments (214, 212, 211) through process liquid overflows to the previous one (212, 211, 210), without the possibility of liquid backflow; the process liquid is led from the trough (216) of the first compartment (210) through a process liquid overflow into a collection tank (219); the process liquid is passed through a liquid inlet into the last compartment (214); the gases are dehumidified in the last compartment (214);the gas flow is quenched with water vapor and equalized thermally in the different compartments (210, 211, 212, 214) in which different controlled concentrations of liquid are stored, creating a true multi-stage countercurrent process design; if cooling of the exhaust gases is required - to limit the plume effect - water is used from an integrated cooling tower (204) in the last compartment and reused for the cooling tower (204) from any intermediate compartment (212); and the dehumidification is preferably carried out by dehumidifiers (31) consisting of three, four or five 31 "stakes" from the top to the bottom of the chamber (218), each "stake (31) being made of sheet metal, bent at an angle, open opposite to the flow direction (32), thus distributing the gas flow lines evenly over the entire cross-sectional area and minimizing the entrapment of droplets between compartments.; 6. The method of claim 5, characterized in that the average linear gas velocity along the chamber (218) is in the range of 3-12 m / s.

7. The method of claim 5, characterized in that chilled water from the integrated cooling tower (204) circuit is introduced into the last compartment (214) and is returned to the cooling tower (204) from any intermediate compartment (212) for recycling.

8. The method of claim 5, characterized in that solutions of increasing concentration are obtained from the overflows of the different compartments (210, 211, 212, 214), and finally a concentrated final liquid is obtained in the sump (216) of the first compartment (210).

9. The method of claim 5, characterized in that the gases are contacted with liquids of controlled concentration in a series of compartments (210, 211, 212, 214).

10. The method of claim 5, wherein the addition of the reactant (206, 207) is controlled by feedback continuous analysis of the solution in one of the intermediate compartments (212).

11. The method of claim 5, characterized in that a basic reactant (206, 207) is introduced into any of the compartments (210, 211, 212, 214).

12. The method according to claim 11, characterized in that the basic reactant (206, 207) is distributed between several compartments (210, 211, 212, 214) or sprayed into the hot gas inlet (201).