WO2007079507A1

WO2007079507A1 - Method for the oxidation of oxidizable exhaust gases with the aid of scrubbing liquid, and corresponding device

Info

Publication number: WO2007079507A1
Application number: PCT/AT2005/000509
Authority: WO
Inventors: Juanito Horn; Andreas Stepan
Original assignee: Juanito Horn; Andreas Stepan
Priority date: 2006-01-11
Filing date: 2006-01-11
Publication date: 2007-07-19

Abstract

Disclosed is a method for oxidizing oxidizable waste gases (9, 9', 9') with the aid of scrubbing liquid. Said method is characterized in that atomic oxygen and/or OH radicals is/are formed by means of electrodes (27, 27') that are disposed in the scrubbing liquid, whereby the waste gases are oxidized. The inventive device comprises an electrolytic cell that is used for oxidizing the waste gases, is integrated into the circuit of the scrubbing liquid, and is provided with electrodes (27, 27') which are arranged in the scrubbing liquid and by means of which atomic oxygen and/or OH radicals can be formed. The invention helps eliminate or at least reduce chemically oxidative substances and/or dispense with or reduce the need for a catalytically active denitrification plant and/or a desulfurization plant.

Description

METHOD FOR OXIDIZING OXIDIZABLE EXHAUST GASES USING WASHING FLUID AND A CORRESPONDING DEVICE

The invention relates to a method for oxidizing oxidizable exhaust gases using washing liquid and a corresponding device.

As an example, a stainless steel pickling (Fig. 1) is cited to illustrate the invention. In order to achieve a good degree of purity of metallic strips, their surface must be freed in the course of the further processing of adhering oxide layers of the scale that formed during previous heat treatment. Scale removal is accomplished by a chemical process, pickling, while passing the scale-covered bands through multiple acid baths. The pickling agent is a preheated acid mixture (mixed acid) of nitric acid and hydrofluoric acid diluted with water. By the effect of temperature in the pickling baths occurs during the pickling process repeatedly to very unpleasant and environmentally harmful reactions of the NO ₃ ^"anion for NOX formation. This toxic gas is dzt. Sucked off via vacuum by means of exhaust fan and supplied to the gas-washing columns. In these absorption columns Subsequently, the environment is relieved by the cleaning or absorption of the exhaust gases.The NOX exhaust gases must be subjected to a very lengthy and expensive purification process, whereby a chemical oxidation by means of hydrogen peroxide (H ₂ O ₂ ) in concentrated form, directly into the scrubbing liquid, whereby a large part of the NOX flue gas is oxidized and recovered again as HNO _3. Disadvantage, however, is the dilution effect within the recovered solution by the addition of H ₂ O ₂ hydrogen peroxide in concentrated for m is expensive and difficult to dose. Furthermore, the remaining NOX exhaust gas will be subjected to a further purification step, since the NOX concentration is too high to be discharged into the environment. For this purpose, the NOX exhaust gas is fed into a so-called DENOX plant, where the NOX gas is converted to N ₂ and CO ₂ - gas here. The resources are substantial. It must be installed appropriate catalysts, a liquid ammonia (NH ₃ ) metering unit must be provided and means another risk to pollute the environment. The gas must be brought to a certain temperature, which in turn is reflected in costs. Now, the NOX gas has been reduced to N ₂ and CO ₂ gas, and can be released into the environment via the roof. The so destroyed NOX shares are compensated through the purchase of HNO _3.

Similarly, the reduction of SO ₂ - flue gas proceeds. Either by chemical oxidation or by conversion of the SO _{2 to} SO ₃ anion to ultimately yield it as CaSO 4. Again, the lost amounts of SO _{4 are} replaced by sulfuric acid.

Organic solvents are destroyed by H ₂ O ₂ or other strong chemical oxidants.

Hard water-soluble hybrids occur in conjunction with the solids boron, silicon, phosphorus, arsenic, antimony, selenium and tellurium and are oxidized by H ₂ O ₂ or NaOCl (sodium hypochlorite) to the corresponding acids and salts. NOX - removal from the exhaust air

NOx-containing waste gases from the inorganic industry resulting from galvanic processes, pickling baths and other processes will now be described. The NOx-containing exhaust gases consist of the most important components NO, NO ₂ , N ₂ O ₄ and N ₂ O ₃ . These components are linked by the following reaction equilibria:

(D 2 NO + O ₂ <→ - 2 NO ₂ Δ HR = + 26,920 cal

(2)) 2 NO ₂ N ₂ O ₄ Δ HR = + 13,600 cal

(3) NO + NO ₂ N ₂ O ₃ Δ HR = + 9,600 cal

Other equilibria play a minor role. The rate-limiting reaction step of this reaction scheme is Equation (1). From temperatures of about 50 ° C, the equilibrium of equation (2) is completely shifted in the direction of NO ₂ . The BUNSEN absorption coefficient α and the Henry coefficient for the gaseous N compounds are shown as follows (see PISCEK, L., and S. BISTRON: Ochnovremennoe obezrezenivanie okislov azota i sery v energeticeskich gazakh - osnovoy element strategy ochany okuruzajuscej sredy. Symposium in Piatra Neamt (Romania 1984)): α H (298 K) kPa

NO 0.000025 2.15-2.92x10

NO ₂ 0.0005 1, 01 - 1, 37 x 10

N ₂ O ₃ 1, 66 x 10 ²

N ₂ O ₄ 1, 6 2.5 - 5.91 x 10 ³

ENT ₂ 37

ENT ₃ 1140

This comparison shows that a direct contribution of NO and NO ₂ to the acidity of the aqueous phase can be excluded. The solubility of N ₂ O _4, on the other hand, is good and approximately equal to that of SO ₂ .

In the following points, only the cleaning procedures alkaline wash and acid wash for nitric acid recovery are considered.

Alkaline wash:

NOX-containing exhaust gases are often cleaned by alkaline washing with caustic soda, potassium hydroxide solution or a mixture with hydrogen peroxide. This procedure has a high salt load for the wastewater to be disposed of. In alkaline washing with NaOH, e.g. the following reactions:

(4) 2NO ₂ + 2 NaOH NaNO ₃ + NaNO ₂ + H ₂ O + 55,400 cal

(5) NO + NO 2 + 2 NaOH 2 NaNO ₂ + H ₂ O + 45,100 cal

(6) 2N ₂ O ₃ + 2 NaOH <H> 2 NaNO ₂ + H ₂ O + 35,500 cal

In addition, in these reactions, the formation of nitric acid, or nitrous acid, as well as the heat of neutralization of these acids by the alkalis must be taken into account as follows:

(7) NaOH. 10H ₂ O + HNO ₃ .100H ₂ O + 13,840 cal

(8) NaOH + HNO ₂ ,, + 11,100 cal

Acid wash to the nitric acid return αewinnunα:

In nitric acid recovery very complex and overlapping reactions take place, which make design and procedure very difficult. The following reaction scheme can be assumed for the different components:

O) 3 NO ₂ + H ₂ O • fr »2 HNO ₃ + NO Δ H _R = + 32,530 cal

(10) N ₂ O ₄ + H ₂ O • fr »HNO ₃ + NHO ₂ Δ H _R = + 14,130 cal

(10a) 3 N ₂ O ₄ + 2 H ₂ O 4 HNO ₃ + 2 NO

(11) N ₂ O ₃ + H ₂ O • fr »2 NHO ₂ ΔH _R = + 13,300 cal

(12) 3 HNO ₂ • fr »HNO ₃ + 2 NO + H ₂ O Δ H _R = - 18,130 cal

If the process conditions are set so that the amounts of N ₂ O _{3 are} small and can be neglected, the calculation is often according to GI. (9). This shows that in the formation of nitric acid 1, 5 times as much oxygen must be oxidized, as is needed for a cycle.

This is also the case when the formation of nitric acid is considered by equations (10) or (10a). This shows that in the recovery of nitric acid, Eq. U is the rate-determining step with the NO regenerated. This is particularly important for the realization and maintenance of small NOx residual concentrations.

Process for accelerating the reaction of NO oxidation

(13) 2 NO + 3 H ₂ O ₂ 2 HNO ₃ + 2 H ₂ O shows that this reaction accelerates the oxidation time of NO.

The acceleration of NO oxidation with hydrogen peroxide was described in DE 2654234 B2 (1978) and by BAVEJA, KK, D. SUBBARADO and MK SAKAR: Kinetics of Absorption of Nitric Oxide Hydrogen Peroxide Solutions. J. Chem. Engineering. Japan 12 (1979) 4, p. 322-325 extensively studied. Compared to the reaction in the system NO-NO ₂ -H ₂ O, significantly faster reaction mechanisms are detected. Koppe have developed a model in which a catalytic reaction acceleration takes place by the elimination of radicals in the liquid phase. Also MAYLAND, BJ, and RC Heinze: Continuous Catalytic Absorption for Nitrogen Oxides Emission Control. AICHE Symposium Ser.70; 137, pp. 83-87, have already demonstrated the catalytic acceleration of this liquid-phase reaction.

A catalytic acceleration compared to the homogeneous gas-phase reaction according to Eq. {1] was u.a. by DURAM, J.L., J.H. OVERTON and V.P. ANEJA: Influence of gaseous nitric acid on sulphate production and acidity in rain. Atmos. Environ. 15 (1981) pp. 1059-1068, successfully detected. Suitable catalysts are e.g. special activated carbons, silica gel, molecular sieves, vanadium and chromium-zinc catalysts. Thereby, e.g. the following

Process Temp. ⁰ C Rate Constant Minute Homogeneous Gas Phase Reaction 25 0.66 x 10 ⁶ Catalytic Reaction on Activated Carbon 25 0.6 x 10 ⁹

This corresponds to a faster implementation by a factor of 1,000. A disadvantage here is the use of activated carbon and silica gel that occurs due to the high water vapor content in nitric acid catalyst intoxication occurs.

For the recovery process of nitric acid from NOx-containing exhaust gases can be calculated according to Eq. (7) set the necessary conditions. The transfer of the NOX components NO and NO ₂ into N ₂ O ₄ and the creation of the reaction conditions for this, so that the liquid phase reaction can be carried out optimally to the nitric acid, play a decisive role. The invention is now characterized in that atomic oxygen and / or OH radicals are formed by electrodes arranged in the washing liquid, and thereby the exhaust gases are oxidized.

The stated object of avoiding or at least reducing chemically oxidative acting Susbtanzen and / or avoidance or reduction of a catalytically acting Entstickungsanlage is thus solved by an integrated electrolysis. For example, an electrode package is installed within the wash fluid circuit which either generates O ₂ atomically and / or forms OH radicals and thus the NO, N ₂ O, NO ₂ , N ₂ O ₃ etc. (nitrous gases) at least to HNO ₂ oxidized to then react in the absorption liquid to HNO ₃ , or analogously to SO ₂ to SO ₃ or SO ₄ , oxidized organic solvents and heavy water-soluble hybrids or cyanides are decomposed.

The following principles must be taken into account:

The entire process control of this invention is thus dependent solely on the parameters, temperature of the washing process, especially the exhaust gas temperature, the residence time, choice of washing liquid and the current strength of the electrolysis. In the developed process, a process is carried out for the NOX removal with nitric acid and the electrolytic conversion of NO to NO ₂ in the gas phase, which operates without dosing of hydrogen peroxide at extremely low clean gas concentrations. By observing the required reaction temperature, the maximum conversion to N ₂ O _{4 is} ensured.

Example of use:

For a pickling bath with 24 m ³ content, an encapsulated process was implemented. The extracted via the exhaust fan exhaust air was limited by a metering orifice. The extracted air volume could be adjusted continuously to a value of about 500 m ³ / h, without the pickling process being adversely affected. The NOx loading is 1,000-5,000 ppm, with peaks of 10,000 ppm, with a NO / NO ₂ ratio of 1:10. This results in the following raw gas loads.

NO 909 ppm 1.217 mg / m ³ 608.5 g / h 20.28 mol / h

NO2 9,090 ppm 18,659 mg / m ³ 9,329.5 g / h 202.8 mol / h

Total 10,999 ppm 19,976 mg / m ³ 9,938.0 g / h 223.08 mol / h

Conventional NOX-Reiniαunα

The NOX-containing exhaust air to be cleaned is fed to five series-connected packed-type scrubbers with a diameter of 950 mm and a packed bed height of 5,600 mm.

The washing cycle is operated with a 20% sodium hydroxide solution. According to the alkaline washing process described in the paragraph, the following NO x reductions result in the individual columns:

NOx inlet NOx outlet Absorptance Degree of absorption to raw gas mg / m ³ mg / m ³ %%

Column 1 19,876 10,733 46.0 46.0

Column 2 10,733 5,425 49.5 72.7

Column 3 5,425 2,410 55.6 87.9

Column 4 2,410 1,150 52.3 94.2

Column 5 1,150 480 58.3 97.6 Alternatively, a smaller number of columns can be selected, but then the column diameter must be increased.

The degradation product is 218.3 kg / d of NaNO ₂ and 187.7 kg / d of NaNO ₃ , or a total of 406 kg / d of salt load, which must be disposed of. For the practical process implementation, the concentration for the wash cycle must not be too high, otherwise crystallization and clogging are to be expected. Let's go from a max. Salt load of 10%, this results in a disposal wastewater quantity of 4 m ³ / d. The soda lye requirement is about 860 l / d of 25% solution. The dissipated heat of reaction is 7.5 kW.

The statutory clean gas values of <500 NOX mg NOX / m ³ are complied with.

The formation of the oxygen or OH radical at the anode (placed titanium steel plate or diamond electrode or lead / tin electrode, in particular lead93 / tin7 electrode) replaces any further oxidizing agent. The cycle washing liquid acts as an electrolyte and has correspondingly high electrical conductivity. In such a configuration, a corresponding amount of direct current is now applied directly to the electrodes, so that the resulting O ₂ or OH radical with the NOX gas particles flowing past either to HNO ₂ and subsequently to HNO ₃ or NO ₃ -SaIz, if an alkaline wash is provided, it can react. Similarly, SO _{2 is} oxidized to SO ₃ - anion and later transformed into a sulfate ion. Of course, a highly enriched with O ₂ and OH radicals washing liquid such as: water can be used, which is sprayed directly into the gas phase. Furthermore, similar to the examples given, organic solvents or heavy water-soluble hybrids are also oxidized and thus destroyed.

An advantage of the invention is that the use of electrolysis O ₂ or OH radicals are formed which allow the oxidation of NOX, SOX, cyanides or organic solvents and heavy water-soluble hybrids, and therefore no additional dosage of oxidizing agent is necessary.

One of the outstanding results of this invention is that the downstream DENOX plant can be minimized to reduce NOX to N ₂ and CO ₂ , while at the same time saving resources for the DENOX plant.

Another outstanding result of this invention is that the downstream DESOX plant, to minimize SOX can be omitted and at the same time there is a saving of resources for the DESOX plant.

A favorable embodiment of the invention is characterized in that the direct current is impressed directly on the diamond and / or lead / tin electrode, in particular a lead93 / tin7 electrode, and thus form OH radicals, which are used for the oxidation of exhaust gases from the general industry.

A favorable embodiment of the invention is characterized in that the direct current is impressed directly on the platinum-plated titanium steel electrode, and thus atomically forms O ₂ , which leads to the oxidation of exhaust gases from the general industry.

An advantageous development of this invention is characterized in that this oxidation possibility also comes with other gases, such as SO ₂ (sulfites), organic solvents or heavy water soluble hybrids used.

It is advantageous that the column effluent is a valuable substance, such as HNO ₃ or nitrate salts or H ₂ SO ₄ , sulfate salts or H ₃ PO ₄ , phosphate salts and can be reintroduced into the process.

The invention can be very easily and subsequently incorporated into the wash cycle system of a conventional absorption column.

One of the most important advantages of this invention is that this device can be used in a wide variety of gas scrubber types, e.g. Packed body scrubbers, spray columns, jet scrubbers, self-aspirating jet scrubbers, cross-flow scrubbers, venturi scrubbers, rotary cones - Venturi, quench columns, spray condensation scrubbers, compact gas scrubbers are used.

The diamond and / or lead / tin electrode, in particular a lead93 / tin7 electrode, has a high stability to aggressive washing solutions.

One of the outstanding results of this invention is that the platinized titanium electrode has a high stability against aggressive washing solutions.

The electrodes can thus be used in acidic and alkaline washing solutions. An advantageous development of this invention is characterized in that the direct current is stamped alternately on the electrodes, which means that the electrodes can always be alternately applied cathodically then anodically and again cathodically with direct current.

A favorable embodiment of the invention is characterized in that the direct current is preferably embossed directly pulsating on the diamond and / or lead / tin electrode, in particular a lead93 / tin7 electrode, or platinum-plated titanium steel electrode.

An advantageous embodiment of the invention is characterized in that the direct current can be applied continuously to the electrodes.

A favorable embodiment of the invention is characterized in that as the electrolyte (cycle washing water) mineral acids, mixed acid or alkaline electrolytes, such as: Na ₂ SO ₄ or K ₂ SO ₄ or NaOH or KOH can be used.

An advantage of the invention is that an accurate maintenance of the concentration of the column effluent is possible, thereby increasing the quality of nitric acid, sulfuric acid or phosphoric acid.

An advantageous variant of the invention is characterized in that the speed of the oxidation of the exhaust gas is determined by regulating the flow of current.

The invention will now be described by way of example with reference to the drawings, in which Fig. 1 shows the scheme of a conventional chemical etching pickling plant such as e.g. through the mixed acid with subsequent absorption column shows. Fig. 2 shows a plant according to the inventive method. Fig. 3 shows an oxidation cell according to the inventive method

Fig. 1 shows a pickling tank (1) according to the prior art. The metal strip (2) is passed through the Abhaspei (14) by degreasing tanks, not shown, then cleaned with deionized water in the sink (3) to then in the pickling tank (1) with the mixed acid (4) (HF / HNO ₃ ) the chemical Removal of the scale begins. The mixed acid (4) is passed from a pump (5) via a line (6) in the pickling tank (1) and discharged via a line (7), for example in an intermediate container (8), where the mixed acid (4) is recirculated again , The metered addition of a urea solution (13) via a pump (11) directly into the absorption column (11) and is made for environmentally conscious reason, thus the NOX content is reduced. The strip (2) is cleaned after the pickling section (1) with deionized water in the sink (3) of adhering mixed acid, then freed by a fan in the dryer from water and rolled up on the reel (14 '). The resulting NOX exhaust gases (9) are brought by means of an exhaust fan (10) in the exhaust gas scrubbing column (11) and washed over a scrubber, not shown again thereafter in a DENOX system (12) the remaining NOX shares catalytically to N ₂ and reduce CO ₂ .

The DENOX system (12) contains the catalyst (20), a line (18) is provided for supplying energy (heating), and a line (19) is provided for supplying ammonia gas. The purified exhaust gas is fed to a chimney (21).

The absorption column (11) has a sump (16), the circulation (16 ^' ) of the sump is accomplished via a circulation pump (25). The outlet (17) of the absorption column (11) is guided into the intermediate container (8).

Instead of a urea solution (13), other reducing or oxidizing substances can be supplied, such as H ₂ O ₂ , fine clay or ozone.

2 shows a plant according to the inventive method, for a pickling tank (1) according to the prior art in which, as shown in FIG. 1, NOX exhaust gases (9) arise. The NOX exhaust gases (9) are brought out of the system by means of exhaust fan (10) and fed to an absorption column (11, 11 '). The absorption column (11, 11 ') is now provided with an integrated oxidation apparatus (22, 22'), which now oxidizes the exhaust gases (9, 9 ') electrolytically, and in the outlet (23, 23') the valuable material (24) is collected and can be routed back to the pickling tank (1). The thus purified exhaust gas (9 ") is now brought into the scrubber, not shown, in which case analogous to the absorption column (11), the oxidation of the exhaust gas (9") by means of an integrated electrolysis (22, 22 ') happens. The cleaned exhaust gas can be returned to the chimney (21). The circulation of the sump is again ensured by circulation pumps (25, 25 ').

3 shows an apparatus (22) which is installed in the scrubber cycle, which is operated by means of pump 25. Consisting of platinized titanium anodes or diamond and / or lead / tin anodes, in particular lead93 / tin7 anodes (27), cathodes (27 '). These electrodes (27 and 27 ') may be made of plate or stretch material and are connected to a rectifier (26).

LIST OF REFERENCE NUMBERS

1 pickling tank

2 metal band

3 sink

4 mixed acid

5 pump

6 line into the pickling tank 1

7 line of pickling tank 1 in intermediate container. 8

8 intermediate containers

9, 9 ^' , 9 "NOX exhaust gases

10 exhaust fan absorption column

DENOX system

Uncoiler 'rewinder

pump

Swamp 'Upswing of the swamp 16

Sequence of the absorption column 11

Line for energy supply

Conduction for ammonia gas

catalyst

Fireplace, 22 'Oxidation Apparatus, 23' drain

Recyclable material, 25 'circulation pumps

rectifier

Anode 'cathode

Claims

claims

Method for oxidizing oxidizable waste gases (9, 9 ', 9 ") using washing liquid, characterized in that atomic oxygen and / or OH radicals are formed by electrodes (27, 27') arranged in the washing liquid, and thereby the exhaust gases are oxidized.

2. The method according to claim 1, characterized in that at least one diamond anode and / or at least one lead / tin anode, in particular a lead93 / tin7 anode, is used.

3. The method according to claim 1, characterized in that at least one platinum-plated titanium steel anode is used.

4. The method according to claim 1, characterized in that the electrodes directly into the washing cycle system (25, 25 ') of a, in particular conventional, waste gas scrubbing column (11) and / or in the sump (16), are installed.

5. The method according to any one of claims 1 to 4, characterized in that a pulsating task of the direct current to the electrodes (27, 27 ') takes place.

6. The method according to any one of claims 1 to 4, characterized in that a continuous application of the direct current to the electrodes (27, 27 ') takes place.

7. The method according to any one of claims 1 to 6, characterized in that the task of the direct current to the electrodes (27, 27 ') takes place alternately.

8. The method according to any one of claims 1 to 7, characterized in that it is used in addition to the destruction of organic solvents by the electrolytic oxidation.

9. The method according to any one of claims 1 to 8, characterized in that in addition to the destruction of heavy water-soluble hybrids, such as PH ₃ , AsH ₃ , SbH ₃ , Si ₂ H _6, B ₂ H ₅ , H ₂ Se and H ₂ Te , is used by the electrolytic oxidation

10. The method according to any one of claims 1 to 9, characterized in that for the oxidation of the exhaust gases, a mixture of mineral acids and water (HNO ₃ , H ₃ PO ₄ or H ₂ SO ₄ ) is used as the electrolyte liquid.

11. The method according to any one of claims 1 to 9, characterized in that for the oxidation of the exhaust gas, a mixture of an alkaline solution such as NaOH, or KOH and / or Na ₂ SO ₄ and / or K ₂ SO _{4 is used} as the electrolyte liquid.

12. The method according to any one of claims 1 to 9, characterized in that is used as the electrolyte liquid mixed acid (mixture of HF / HNO ₃ and HCl).

13. The method according to any one of claims 1 to 12, characterized in that the current intensity is adjusted (amperes per unit area) targeted to the oxidizable constituents in the raw gas, wherein current densities at the electrodes is between 0.5 ^'and 150 A / dm ^2.

14. The method according to any one of claims 1 to 13, characterized in that the temperature is adjusted specifically to the raw gas to be oxidized, wherein the electrolyte temperature is between 20 and 90 ⁰ C, preferably 45 ° C.

15. The method according to any one of claims 1 to 14, characterized in that it is used for the removal of nitrogen oxides and / or sulfur oxides and / or cyanides.

16. An apparatus for oxidizing oxidizable exhaust gases using washing liquid for carrying out the method according to one of claims 1 to 15, characterized in that for the oxidation of the exhaust gases an integrated in the cycle of the washing liquid electrolysis cell is provided, which arranged in the washing liquid electrodes ( 27, 27 ') containing which atomic oxygen and / or OH radicals can be formed.

17. The device according to claim 16, characterized in that at least one diamond anode and / or at least one lead / tin anode, in particular a lead93 / tin7 anode, is provided.

18. Device according to claim 16 or 17, characterized in that at least one platinum-plated titanium steel anode is provided.

19. Device according to one of claims 16 to 18, characterized in that the electrolysis cell directly into the washing cycle system (25, 25 ') of a, in particular conventional, waste gas scrubbing column (11) and / or in the sump (16) is installed.

20. Device according to one of claims 16 to 19, characterized in that it is designed so that a pulsating task of the direct current to the electrodes (27, 27 ') can take place.

21. Device according to one of claims 16 to 19, characterized in that it is designed so that a continuous application of the direct current to the electrodes (27, 27 ') can take place.

22. Device according to one of claims 16 to 21, characterized in that it is designed so that the task of the direct current to the electrodes (27, 27 ') can be done alternately.

23. Device according to one of claims 16 to 22, characterized in that it is used in addition to the destruction of organic solvents by the electrolytic oxidation.

24. Device according to one of claims 16 to 23, characterized in that in addition to the destruction of heavy water-soluble hybrids, such as PH ₃ , AsH _3, SbH ₃ , Si ₂ H ₆ , B ₂ H ₅ , H ₂ Se and H ₂ Te , is used by the electrolytic oxidation

25. Device according to one of claims 16 to 24, characterized in that the current intensity (ampere per unit area) is specifically set to the oxidizable ingredients in the raw gas.

26. Device according to one of claims 16 to 25, characterized in that the temperature is selectively adjustable to the raw gas to be oxidized.

27. Device according to one of claims 16 to 26, characterized in that the materials are resistant to acidic as well as alkaline media.

28. Device according to one of claims 16 to 27, characterized in that it is used for the removal of nitrogen oxides and / or sulfur oxides and / or cyanides.

29. Device according to one of claims 16 to 28, characterized in that the electrodes (27, 27 ') are made of plate, tube or expanded material.