WO2015018796A1

WO2015018796A1 - Method and device for preparing a gas stream, in particular for preparing a flue gas stream

Info

Publication number: WO2015018796A1
Application number: PCT/EP2014/066740
Authority: WO
Inventors: Markus Kinzl; Diego Andres Kuettel; Ralph Joh; Rüdiger Schneider
Original assignee: Siemens Aktiengesellschaft
Priority date: 2013-08-08
Filing date: 2014-08-04
Publication date: 2015-02-12

Abstract

The invention relates to a method for preparing a gas stream, in particular for preparing a flue gas stream, wherein a gas stream is supplied to an absorber (3), carbon dioxide contained in the gas stream is separated in the absorber (3) by means of a washing medium (9), the washing medium (9), loaded with carbon dioxide, is supplied to a desorber (5), the carbon dioxide contained in the washing medium (9) in the desorber (5) is released from the washing medium (9), the washing medium in the desorber (5), freed of carbon dioxide, is supplied to a preparation stage (29) in which sulfur dioxide contained in the washing medium (9) is separated as potassium sulfate, and the washing medium (9) cleaned in the preparation stage (29) is returned to the absorber (3). A regenerable activator (24) is used in the washing medium (9) which increases the absorption rate of the carbon dioxide in the washing medium (9) and/or the desorption rate of the carbon dioxide from the washing medium (9). The invention further relates to a device (1) for performing such a method.

Description

description

Method and device for the treatment of a gas stream, in particular for the treatment of a flue gas stream

The invention relates to a process for the treatment of a gas stream, in particular for the treatment of a flue gas stream. Furthermore, the invention relates to a device for the treatment of a gas flow, in particular for the treatment of a flue gas flow.

Against the background of climatic changes, it is a global goal to reduce the emission of pollutants into the atmosphere. This applies in particular to the emission of carbon dioxide (C0 ₂ ), which accumulates in the atmosphere, hindering the heat radiation of the earth and thus as a greenhouse effect leads to an increase in the Earth's surface temperature.

Particularly in fossil-fired power plants for the generation of electrical energy, the combustion of a fossil fuel produces a carbon dioxide-containing flue gas. To avoid or reduce carbon dioxide emissions into the atmosphere, the carbon dioxide must be separated from the flue gas. Correspondingly, suitable measures are being discussed especially for existing fossil-fueled power plants in order to separate the resulting carbon dioxide from the exhaust gas after combustion (post-combustion capture). As a technical realization, carbon dioxide contained in the flue gas for this purpose is, after combustion, washed out of the respective gas stream by means of a sorption-desorption process by means of a washing medium. For deposition, the flue gas is fed to an absorber as part of a conventional treatment device for separating carbon dioxide (C0 ₂ separation device), wherein gaseous carbon dioxide contained in the flue gas is dissolved in the washing medium or absorbed in a chemical sense. The exempt from carbon dioxide Exhaust gas will eventually release to the atmosphere. The carbon dioxide-laden wash medium can be regenerated by desorbing the absorbed carbon dioxide and reused to absorb carbon dioxide from the flue gas.

In order to increase the absorption rate of carbon dioxide in the washing medium, activators can be used. For example, when using methyldiethanolamine as the washing medium, the addition of an activator such as monoethanolamine or

Diethanolamine lead to an improvement in the reaction rate. However, such activators run the risk of being emitted into the atmosphere due to their vapor pressure with the scrubbing flue gas leaving the absorber.

The associated loss of activator requires a continuous replenishment of new activator material in the washing medium used in the preparation process, which is associated with increased operating costs. In addition, discharge of the activator together with the carbon dioxide-purified flue gas contributes to undesirable environmental impact.

It is therefore a first object of the invention to provide a method with which a cost-effective and effective acceleration of the treatment of a gas stream and in particular a flue gas stream is possible.

A second object of the invention is to provide a device with which a corresponding method can be carried out economically.

The first object of the invention is achieved by a process for the treatment of a gas stream, in particular for the treatment of a flue gas stream, in which a

Absorber is supplied to a gas stream, carbon dioxide contained in the gas stream is deposited in the absorber by means of a washing medium, the loaded with carbon dioxide washing medium an Nem desorber is fed, the carbon dioxide contained in the scrubbing medium is released from the scrubbing medium in the desorber, which is supplied in the desorber freed from carbon dioxide scrubbing medium a treatment stage, in which contained in the scrubbing medium sulfur oxides are separated as potassium sulfate, and purified in the treatment stage Washing medium is returned to the absorber. Here, a regenerable activator is used in the washing medium, which increases the absorption rate of the carbon dioxide in the washing medium and / or the desorption of carbon dioxide from the washing medium.

The invention takes into account that in order to accelerate the absorption and / or the desorption of carbon dioxide in the treatment of a gas stream, the use of an activator is possible. By means of an activator both the absorption process and the desorption process can be accelerated and in this way the effectiveness of the treatment of a

Total flue gas flow can be increased. However, in order to meet the requirements of the environmental compatibility of the deposition process as a whole, it must be prevented that an activated activator is discharged into the atmosphere. Furthermore, an activator loss is to be avoided due to the required efficiency of the treatment process. This is not satisfactorily possible with the use of activators.

In order to circumvent the problem described above, the invention recognizes that it is then possible to meet the requirements for a cost-effective and environmentally friendly treatment of a gas stream, if a regenerable activator is used in the washing medium, the rate of absorption of the carbon dioxide in the washing medium and / or increases the rate of desorption of carbon dioxide from the washing medium.

In principle, all such activators are understood as regenerable activators, which are not or only insignificantly in the context of the treatment process of a gas stream be consumed and thus in the process can be recovered substantially completely.

The regenerability of the activator used gives two advantages at the same time. On the one hand, by increasing the absorption rate of carbon dioxide in the washing medium and the desorption rate of carbon dioxide from the washing medium, the entire treatment process is accelerated. On the other hand, a subsequent dosing of the activator (activator-refill) used in the process is not or only to a very small extent necessary, whereby possible additional costs in the

Implementation of the treatment process can be saved. Preferably, a solid is used as the activator. A solid activator is particularly suitable because it has no appreciable vapor pressure, so that discharge from the deposition process is avoided. The activator can preferably be regenerated or recovered by precipitation in the treatment process. The regeneration of the activator takes place here in particular in the treatment stage, in which also contained in the scrubbing medium sulfur oxides (S0 _X ) are separated by reaction with potassium hydroxide solution (KOH) as potassium sulfate (K ₂ S0 ₄ ) from the washing medium.

Preferably, the activator is dissolved in a solvent and the solution is fed to the washing medium. This is especially necessary because the activator used does not dissolve instantaneously. By a pre-dissolution can thus be ensured a complete dissolution of the activator before dosing in the process and thus a possible blockage of existing in the columns of the absorber and / or desorber used packs are prevented by possible undissolved solid.

Particularly preferably, the activator is pre-dissolved in an alkaline solvent and this solution is fed to the washing medium. For this purpose, an aqueous KOH solution (potassium hydroxide solution) Preferably, which is added to the process especially when using potassium amino acid salts as a washing medium continuously to compensate for the occurring in the treatment stage discharge of potassium - due to the local precipitation of potassium sulfate - compensate. The pre-dissolution in an alkaline solvent has the further advantage that the solubility of the activator therein is relatively high, so that only small amounts of solvent must be used. Furthermore, depending on the solubility of the activator used, it is also possible, for example, to pre-dissolve the activator in the washing medium itself or in water.

The pre-dissolution of the activator is basically associated with little effort, since the solvents used (water, an alkaline solution or the washing medium) are already present in the deposition process and this must be added regularly during the treatment of the gas stream to the continuously occurring Compensate for water and KOH losses and thus maintain the overall mass balance of the treatment process. Furthermore, by using existing water and KOH streams, for example, it is possible to dispense with an additional supply of solvents in order to pre-dissolve the activator before it enters the processing device or the corresponding preparation process.

In an advantageous embodiment of the invention, the activator used is an oxide of at least one element which is selected from the group consisting of the elements from the third main group (boron group), the fourth main group

(Carbon group), the fifth main group (nitrogen group), the fourth subgroup (titanium group), the fifth subgroup (vanadium group), the sixth subgroup (chromium group) and / or the seventh subgroup (manganese group) of the periodic table. These oxides enable a good one

Activation of both the absorption and the desorption process and thus an effective acceleration of the treatment process for carbon dioxide. Here is next to the Use of only one oxide also the use of mixed oxides or mixtures of different oxides as activator conceivable. Preferred as activator B ₂ 0 ₃ , A1 ₂ 0 ₃ , Si0 ₂ , Ge0 ₂ , P ₂ 0 ₃ , As ₂ 0 ₃ , Sb ₂ 0 ₃ , Se0 ₂ , Te0 ₂ , Ti0 ₂ , V ₂ 0 ₅ , Mo0 ₃ , W0 ₃ and / or Ge0 ₂ used. Germanium dioxide (GeO ₂ ) is used in particular, which reacts with alkaline solutions, such as with KOH solution used for pre-dissolution of the activator to germanate.

Preferably, the activator is continuously supplied to the washing medium. In this case, small amounts of the activator, expediently as a solution by predissolving in an alkaline solution, in water or in the washing medium used in the process, flow into the washing medium in the deposition process. The continuous supply of the solution can take place for example by means of a pump in flowing from the absorber sump, loaded with carbon dioxide washing medium. Thus, the losses of the washing medium, resulting for example by degradation reactions, be replaced in the current process.

Alternatively, a discontinuous supply of the activator, also pre-dissolved in an appropriate solvent, is possible. Here, the solid, so the activator prior to dissolution, for example, externally at a

Service providers be pre-dissolved. At the processing device itself, only the dosing of the pre-dissolved activator takes place in the washing medium present in the preparation process.

The pre-dissolved activator is preferably fed into a discharge line connected to the absorber, through which washing medium laden with carbon dioxide flows into the desorber. Alternatively, it is also possible to supply the pre-dissolved activator at other locations of the device. In a particularly advantageous embodiment of the invention, the preparation stage for this purpose comprises a reclaimer (SO _x - reclaimer), in which a solid mixture of activator and potassium sulfate is precipitated from the washing medium. Potassium sulphate precipitates in the treatment stage or in the SO _x reclaimer by the reaction of the sulfur oxides and potassium hydroxide solution contained in the washing medium. For the separation of the potassium sulfate in the context of a reclaiming process, the stream entering the reclaimer from the desorber is cooled to temperatures between 10 and 15 ° C. In this case, a co-crystallization of the activator used occurs. For example, Ge0 ₂ crystallizes in the alkaline solvent in the form of germanate.

Since the highest possible activator concentration is sought in the deposition process in order to achieve the best possible activation, the activator concentration is adjusted to the solubility at the lowest temperature prevailing in the deposition process, which is usually present in the absorber. However, since the absorber temperature is higher than the temperature in the reclaimer and the activator solubility decreases with decreasing temperature falls in the SO _x -Reclaimer the fixed-described mixture of activator and potassium sulfate from. The mass ratio of the two crystallized solids is in the range of 1: 1.

In order to separate the precipitated or crystallized solid mixture, ie the mixture of potassium sulfate and the activator to be regenerated from the washing medium, a separating device is expediently used. As a separation device, for example, is a centrifuge, which allows a simple and effective separation of the solid mixture from the washing medium.

In order to enable an effective regeneration of the activator used and thus to avoid high costs with regard to a possible activator refill, the activator regeneration is carried out by means of a method which is based on the utilization of the significantly lower activity compared to potassium sulfate. Tor solubility in water or in dilute aqueous solution is based.

In a particularly advantageous embodiment of the invention, the activator is separated from the potassium sulfate by means of a washing process. The washing process is followed by the separation of the solid mixture from the washing medium. The solid mixture of potassium sulfate and activator is preferably washed with washing water to separate the components from one another, wherein the potassium sulfate is essentially completely dissolved in the washing water used.

Advantageously, almost the entire proportion of solid activator remains undissolved. While the K ₂ SO ₄ solubility in water or in an aqueous solution at room temperature is about 10% by weight, only a small proportion of activator dissolves in the wash water. When using

Germanium dioxide (Ge0 ₂ ) dissolve from this only about 0.4% by weight. In order to further reduce the solubility of the activator, a small amount of sulfuric acid is additionally added to the washing water used for the washing process.

The amount of washing water used is expediently chosen so that the ratio of the amount of washing water added, based on the amount of potassium sulfate contained in the solid mixture 10: 1, is. Due to the solubility of potassium sulfate of about 10% by weight in water, the entire potassium sulfate contained in the solid mixture dissolves accordingly, while the major part of the activator remains undissolved.

Based on the following example, this can be understood for germanium dioxide as an activated activator. At 2 kg of a separated from the wash medium 1: 1 solid mixture (share K ₂ S0 ₄ and Ge0 ₂ each 1 kg) is added based on the potassium sulfate, the 10-fold amount of wash water (10 kg), so that due to the solubility of potassium sulfate, the total K ₂ S0 ₄ content of the solid mixture in the washing water dissolves. By contrast, only about 40 g of the germanium dioxide dissolve in the wash water, so that about 960 g of GeO ₂ remain as undissolved solid. This easy-to-perform regeneration method thus enables the recovery of about 96% of the germanium dioxide activator precipitated in the reclaimer.

This low-cost method for recovery or regeneration of the activator can in principle be transferred to all - in particular poorly soluble - activators.

The washing medium regenerated in the treatment stage after the precipitation and the subsequent separation of the solid mixture is preferably recycled from the treatment stage or from a reclaimer of the treatment stage into the deposition process.

The solid activator not dissolved in the washing water is preferably separated from the washing water in a separation unit. This can be done for example by filtration, wherein the activator is recovered substantially completely.

Particularly advantageously, the separated activator is returned to the washing medium - in the deposition process - and is there again to accelerate the treatment of a gas stream available. A post-dosing of activator material is hardly or only to a small extent necessary. In the above-described example of a regeneration yield of about 96% of the activator germanium dioxide, for example, a subsequent dosing of only about 4% of the activator used is necessary.

In other words, such a maximum activator concentration in the process can be agreed upon with the minimization of activator refill costs. As with the pre-resolution of the activator, with regard to regeneration, the regeneration process is also possible with an external service provider if required. The solid mixture precipitated in the preparation stage, consisting of potassium sulfate and the activator, can be removed from the process and separated and processed in an external device. The regenerated activator can then be returned to the process. The wash water containing the dissolved potassium sulfate is preferably supplied to a utilization device, where the potassium sulfate is separated from the wash water. Subsequently, the potassium sulfate can be further processed and made available for use, for example, in fertilizers or specialty chemicals.

Conveniently, an amino acid salt is used as the washing medium. An aqueous amino acid salt solution is useful here. In the use of an amino acid salt as a washing medium, it has been found advantageous to use an amino acid salt having a carbon substituent selected from the group consisting of hydrogen, an alkyl, a hydroxyalkyl and an aminoalkyl. More preferably, an amino acid salt having a nitrogen substituent selected from the group consisting of hydrogen, an alkyl, a hydroxyalkyl and a haloalkyl is used. Again, a single amino acid salt, such as a potassium salt of glycine or other amino acids, may be employed. Also, mixtures of different amino acid salts can be used as the absorbent. Particularly preferred is a potassium-containing amino acid salt, or a corresponding aqueous solution of a potassium-containing amino acid salt. Conveniently, at least part of the washing medium flows from the desorber into a reboiler. As a so-called bottom evaporator, the reboiler supplies the necessary heat of regeneration for the separation of absorbed C0 ₂ from Washing medium. The loaded washing medium is in this case regenerated by steam, which is generated in the reboiler. To generate the steam within the reboiler this is usually heated with imported steam, for example from a connected steam power plant.

The second object of the invention is achieved by a device for the treatment of a gas stream, in particular for the treatment of a flue gas stream comprising an absorber for the separation of carbon dioxide from the

Gas stream by means of a washing medium, a fluidically coupled to the absorber desorber for releasing the carbon dioxide from the washing medium, and a fluidically coupled with the desorber treatment stage for the separation of sulfur oxides contained in the washing medium. Here, a regenerable activator is used to increase the absorption rate of the carbon dioxide in the washing medium and / or the desorption of carbon dioxide from the washing medium. By using a regenerable activator on the one hand, the accelerated treatment of a gas stream by increasing the absorption and the desorption of carbon dioxide is favored. Furthermore, a re-dosing of the activator used (activator-refill) in the process only to a small extent necessary.

A solid is particularly preferably used as the activator since a solid activator has no appreciable vapor pressure and thus its discharge from the deposition process can be prevented.

In order to avoid blockages caused by solid deposits in the absorber and desorber columns used, the activator is expediently used in the form of a solution. Preferably, the activator is in an alkaline

Solvent predissolved. Alternatively, it is also expedient to pre-dissolve the activator in the washing medium itself or in water. Advantageously, the activator used is an oxide of at least one element which is selected from the group consisting of the elements from the third main group, the fourth main group, the fifth main group, the fourth subsidiary group, the fifth subgroup, the sixth subgroup

and / or the seventh subgroup of the periodic table. Such oxides, with good regenerability, allow effective acceleration of a separation process carried out in the apparatus.

Particularly advantageous as activator B ₂ 0 ₃ , A1 ₂ 0 ₃ , Si0 ₂ , Ge0 ₂ , P ₂ 0 ₃ , As ₂ 0 ₃ , Sb ₂ 0 ₃ , Se0 ₂ , Te0 ₂ , Ti0 ₂ , V ₂ 0 ₅ , Mo0 ₃ , W0 ₃ and / or Ge0 ₂ used. In a further advantageous embodiment, the device comprises a metering device for supplying the activator to the deposition process. The supply takes place here preferably continuously. Alternatively, a discontinuous feed of the activator is expedient. Regardless of the type of feed, the activator is pre-dissolved and then fed to the separation process.

The preparation stage particularly preferably comprises a reclaimer for precipitating a solid mixture of the activator and potassium sulfate from the washing medium. For separation of the precipitated solid mixture, a separation device is preferably used, wherein, for example, a centrifuge is suitable. In order to separate the activator from the potassium sulfate and thus to allow regeneration, the treatment stage comprises a washing device. In the washing apparatus, a washing of the solid mixture can be carried out with a detergent which is only suitable for dissolving potassium sulfate, but not for dissolving the activator used. In this way, a simple and effective separation of the two components from each other can be achieved. To return the regenerated in Reclaimer washing medium Reclaimer is fluidly connected to a supply line of the absorber. Thus, the washing medium can be used in the process for the re-absorption and desorption of carbon dioxide.

In order to be able to recirculate the activator to the separation process after separation from the potassium sulfate and the washing medium, the reclaimer is preferably fluidically connected to a metering device for the activator.

Conveniently, the metering device is fluidically connected to a discharge line of the absorber. The activator - either at the beginning of the process or after the regeneration - can thus be added to the washing medium flowing out of the absorber sump and flow together with this into the desorber.

In principle, of course, there is also the possibility of coupling the metering device to other locations of the device in terms of flow.

In order to enable an effective separation of the carbon dioxide from the gas stream, an amino acid salt is preferably used as the washing medium. An aqueous potassium-containing amino acid salt solution is useful here.

The desorber is expediently connected to a reboiler which, as a bottom evaporator, supplies the necessary regeneration heat for the separation of absorbed CO ₂ from the washing medium.

Further advantageous embodiments of the device for the treatment of a gas stream resulting from the directed to the method dependent claims. The advantages mentioned can be correspondingly transferred to the device accordingly. In the following an embodiment of the invention will be explained in more detail with reference to a drawing. Showing:

1 shows a device for carrying out a method for the separation of carbon dioxide from a flue gas Ström.

1 shows a device 1 for separating carbon dioxide from a flue gas stream. The separating device 1 comprises an absorber 3 and a desorber 5 fluidically coupled thereto.

For separating carbon dioxide from the flue gas of an incinerator, the flue gas is introduced into the CO ₂ separator 1. For this purpose, the flue gas is supplied to the absorber 3 via a flue gas line 7. In the absorber 3 is located as a washing medium 9, a potassium-containing aqueous amino acid salt solution, which is used to separate the carbon dioxide contained in the flue gas. This is the

Flue gas in the absorber 3 brought into contact with the washing medium 9 and absorbs the carbon dioxide contained in the flue gas in the washing medium 9. The cleaned of carbon dioxide gas stream is discharged from the absorber 3 at the absorber head 11. Via a discharge line 13, the absorber 3 is fluidly coupled to a feed line 15 of the desorber 5, so that the laden with carbon dioxide washing medium 9 can be pumped via these two lines 13, 15 with temperature increase by means of a pump 17 in the desorber 5.

In this case, the loaded washing medium 9 passes through a heat exchanger 19 in which the heat of the regenerated washing medium 9 flowing from the desorber 5 to the absorber 3 is transferred to the laden washing medium 9 flowing out of the absorber 3. The heat exchanger 19 thus uses the waste heat of the desorber 5 to preheat the washing medium 9 from the absorber 3 before entering the desorber 5. Within the desorber 5, the carbon dioxide absorbed in the washing medium 9 is thermally desorbed. For the treatment and transfer of the carbon dioxide, the desorber 5 is connected to a discharge line 21, which opens into a recycling device 23. In the utilization device 23, the desorbed C0 ₂ -rich gas stream can be compressed to allow, for example, the transport to a storage site. To accelerate the absorption and the desorption in the treatment of the flue gas stream, a regenerable activator 24 is used. The activator 24, in the present case the solid activator germanium dioxide (GeO ₂ ), increases both the absorption rate of carbon dioxide in the washing medium 9 within the absorber 3, and the desorption rate of carbon dioxide from the washing medium 9 in the desorber 5.

Furthermore, through the use of a regenerable activator 24, a subsequent dosing (activator refill) in the process is almost not necessary, so that the treatment process can be carried out economically and effectively.

The activator 24 is pre-dissolved in a metering device 25 in potassium hydroxide solution and introduced continuously from the metering device 25 via a metering line 27 into the discharge line 13 of the absorber 3. The pre-dissolved activator 24 thus passes together with the emerging from the absorber 3, loaded with carbon dioxide washing medium 9 in the desorber 5 and is available to accelerate the deposition process available.

Basically, this also applies that a discontinuous dosage of the pre-dissolved activator 24 in the process is possible. The preliminary resolution then takes place, for example, with an external service provider. Finally, only the metering of the pre-dissolved activator 24 into the washing medium 9 used in the process or the device 1 takes place on the device 1 itself. The regeneration or the recovery of the activator 24 takes place in a treatment stage 29, which is fluidically connected to the desorber 5. For this purpose, a return line 31 of the desorber 5 is coupled to a feed line 33 of the treatment stage 25. The feed line 33 is part of a bypass 35. The scrubber 9 freed of carbon dioxide in the desorber 5, in which the dissolved activator 24 is located, is fed to the treatment stage 29 via the fluidic coupling of the return line 31 to the feed line 33.

The treatment stage 29 comprises a reclaimer 37 in which sulfur oxides contained on the one hand in the washing medium 9 are precipitated out of the washing medium 9 by a drop in temperature and by reaction with potassium hydroxide solution as potassium sulfate. Furthermore, the activator 24 contained in the washing medium 9 is precipitated. The recovery of the activator 24 thus takes place in one process step together with the separation of potassium sulfate formed in the process.

The washing medium 9 flowing into the reclaimer 37 from the desorber 5 is cooled to 10 ° C. to 15 ° C., with co-crystallization of the germanium dioxide activator 24 taking place in addition to the crystallization of potassium sulfate. This crystallizes in the form of germanate.

In the solid mixture, the activator 24 and the potassium sulfate are present in a mass ratio of about 1: 1. The solid mixture is then separated from the washing medium 9 by a separating device 39 designed as a centrifuge and finally washed in a corresponding washing device 41 with detergent or washing water. In order to achieve a separation of the solid mixture and thus to regenerate the activator 24, one uses the higher solubility of the potassium sulfate compared to the activator 24. While the K ₂ S0 ₄ solubility in water at room temperature about 10 -g. %, only a small proportion of activator 24 dissolves in the wash water. With the use of germanium dioxide of this dissolve only about 0.4 wt.%. The amount of washing water used is expediently chosen so that the ratio of the amount of the added wash water, based on the amount of potassium sulfate contained in the solid mixture is 10: 1. Due to the K ₂ S0 ₄ solubility of about 10% in water accordingly dissolves all the potassium sulfate contained in the solid mixture, while most of the activator 24 remains undissolved.

The activator 24 is then separated from the washing water in the treatment stage 29 in a further separation process and returned via a discharge line 43 from the processing stage 29 and the reclaimer 37 into the metering device 25. Thus, after the separation of the potassium sulfate and the washing medium 9, the activator 24 can be returned to the deposition process.

The washing medium 9 itself, which has been regenerated in the preparation stage 29 after the precipitation and the subsequent separation of the solid mixture, is likewise returned to the preparation process via a return line 45 which is part of the bypass 35. For this purpose, the reclaimer 37 is fluidically connected to a supply line 47 of the absorber 3. When using an external service provider, in which regeneration of the activator 24 can likewise be carried out, it is possible to dispense with a washing device 41, which in the present case is used to wash out the potassium sulfate from the solid mixture and thus to recover the activator 24.

The potassium sulfate dissolved in the washing water is preferably fed to a utilization device 49 and there correspondingly separated from the washing water. Subsequently, the potassium sulfate can be further processed and made available for further use, such as in fertilizers or specialty chemicals.

Furthermore, the desorber 5, a reboiler 51 is connected, which serves to provide the necessary heat of regeneration for the separation of carbon dioxide from the washing medium 9. The loaded washing medium 9 is in this case regenerated by steam, which is generated in the reboiler 51. The reboiler 51 is heated with imported steam, for example from a connected steam power plant, which is not shown here.

Claims

claims

1. A process for the preparation of a gas stream, in particular for the treatment of a flue gas stream, in which

an absorber (3) is supplied with a gas stream,

carbon dioxide contained in the gas stream is deposited in the absorber (3) by means of a washing medium (9), the carbon dioxide-laden washing medium (9) is fed to a desorber (5),

- The carbon dioxide contained in the scrubbing medium (9) in the desorber (5) is released from the scrubbing medium (9) in the desorber (5) freed of carbon dioxide scrubbing medium (9) is fed to a treatment stage (29), in the washing medium ( 9) contained sulfur oxides as potassium sulfate, and

the washing medium (9) purified in the treatment stage (29) is returned to the absorber (3),

wherein in the washing medium (9) a regenerable activator (24) is used, which increases the absorption rate of the carbon dioxide in the washing medium (9) and / or the desorption of the carbon dioxide from the washing medium (9).

2. The method of claim 1, wherein a solid is used as the activator (24).

3. The method according to claim 1 or 2, wherein the activator (24) is dissolved in a solvent and the solution is supplied to the washing medium (9).

4. The method according to any one of the preceding claims, wherein as activator (24) an oxide is used at least one element which is selected from the group, the elements of the third main group, the fourth main group, the fifth main group, the fourth subgroup, the fifth subgroup, the sixth subgroup and / or the seventh subgroup of the periodic table.

5. The method according to any one of the preceding claims, wherein as activator B ₂ 0 ₃ , A1 ₂ 0 ₃ , Si0 ₂ , Ge0 ₂ , P ₂ 0 ₃ , As ₂ 0 ₃ , Sb ₂ 0 ₃ , Se0 ₂ , Te0 ₂ , Ti0 ₂ , V ₂ 0 ₅ , Mo0 ₃ , W0 ₃ and / or Ge0 _{2 is} used.

6. The method according to any one of the preceding claims, wherein the activator (24) is supplied to the washing medium (9) continuously.

7. The method according to any one of the preceding claims, wherein the processing stage (29) comprises a reclaimer (37) in which a solid mixture of the activator (24) and potassium sulfate from the washing medium (9) is precipitated.

8. A method according to claim 7, wherein the activator (24) is separated from the potassium sulfate by means of a washing process.

9. The method of claim 7 or 8, wherein the separated activator (24) is returned to the washing medium (9).

10. The method according to any one of the preceding claims, wherein as the washing medium (9) an amino acid salt is used.

11. Device (1) for the treatment of a gas stream, in particular for the treatment of a flue gas stream, comprising an NEN absorber (3) for the separation of carbon dioxide from the

Gas stream by means of a washing medium (9), a desorber (3) coupled to the desorber (5) for releasing the carbon dioxide from the washing medium (9), and a fluidically with the desorber (5) coupled processing stage (29) for the separation from in the washing medium (9) contained sulfur oxides, wherein in the washing medium (9) a

regenerable activator (24) is used to increase the absorption rate of the carbon dioxide in the washing medium (9) and / or the rate of desorption of the carbon dioxide from the washing medium (9).

12. Device (1) according to claim 11, wherein a solid is used as the activator (24).

13. Device (1) according to claim 11 or 12, wherein the activator (24) is used in the form of a solution.

14. Device (1) according to one of claims 11 to 13, wherein the activator (24) used is an oxide of at least one element which is selected from the group comprising the elements from the third main group, the fourth main group, the fifth main group, the fourth subgroup, the fifth subgroup, the sixth subgroup and / or the seventh subgroup of the periodic table.

15. Device (1) according to one of claims 11 to 14, wherein as an activator (25) B ₂ 0 ₃ , A1 ₂ 0 ₃ , Si0 ₂ , Ge0 ₂ , P ₂ 0 ₃ , As ₂ 0 ₃ , Sb ₂ 0 _3rd , Se0 ₂ , Te0 ₂ , Ti0 ₂ , V ₂ 0 ₅ , Mo0 ₃ , W0 ₃ and / or Ge0 ₂ are used.

16. Device (1) according to one of claims 11 to 15, comprising a metering device (25) for supplying the activator (24).

17. Device (1) according to any one of claims 11 to 16, wherein the processing step (29) comprises a reclaimer (37) for precipitating a solid mixture from the activator (24) and potassium sulfate from the washing medium.

18. Device (1) according to any one of claims 11 to 17, wherein the treatment stage (29) comprises a washing device (41) for separating the activator from the potassium sulfate.

19. Device (1) according to claim 17 or 18, wherein the reclaimer (37) is fluidically connected to a supply line (47) of the absorber (3).

20. Device (1) according to any one of claims 17 to 19, wherein the reclaimer (37) fluidly with the

Dosing device (25) for the activator (24) is connected.

21. Device (1) according to claim 20, wherein the metering device (25) is fluidically connected to a discharge line of the absorber (13).

22. Device (1) according to any one of claims 11 to 21, wherein as the washing medium (9) an amino acid salt is used.