WO1982004406A1

WO1982004406A1 - Process for the elimination of toxic substances from exhaust gases

Info

Publication number: WO1982004406A1
Application number: PCT/DE1982/000121
Authority: WO
Inventors: Albin Boehmeke; Rainer Fries
Original assignee: Albin Boehmeke; Rainer Fries
Priority date: 1981-06-05
Filing date: 1982-06-05
Publication date: 1982-12-23
Also published as: DE3122349C2; DE3122349A1; EP0080491A1

Abstract

Process for the elimination of toxic substances from exhaust gases, especially sulphur oxides and halogen vapors, by causing a calcium compound to react with the sulphur oxides or halogen vapor, the calcium compound being mixed with a soluble binding agent and made into packing solids of predetermined shape, dried and then loosely disposed in the exhaust stream in such a way that sufficient throughdraft is allowed for the operation of the installation producing the gases.

Description

Process for removing pollutants from exhaust gases

The invention relates to a method for eliminating pollutants from exhaust gases.

Increasing industrialization is placing increasing strain on the environment. This concerns above all pollutants that are released from industrial plants to the environment in an increasingly threatening manner, so that serious damage to the environment has already occurred. In order to reduce these harmful influences to a minimum, the first Air Pollution Control Act was passed in December 1959, which was followed in 1975 by the Federal Immission Control Act, which stipulated maximum permissible concentrations of pollution for pollutants from industrial plants, especially for fluorine. In general, this maximum permissible immission concentration for fluorine is 0.003 mg / m ³ exhaust gas.

When firing ceramic masses, the emission in the exhaust gases is particularly high. To counteract this, lime was added to the ceramic masses in appropriate amounts, whereby the fluorine was bound as calcium fluoride and could thus be rendered harmless. However, this route can only be used with inferior ceramic masses, so that in the main production of high-quality ceramic goods, fluorine is released to the dip environment in a no longer portable frame. On the other hand, in order not to exceed the permissible immission values prescribed by law a number of attempts have already been made to minimize the fluorine immission in the exhaust gases,

Thus, in the "Reports of the German Ceramic Society", Issue 1, 1977, on page 9, in the publication by Klaus Jepsen and Ernst Schmidt on "Experience with emission measurements in the ceramic industry", a method with an apparatus has already been described, whereupon fluorine can be removed from exhaust gases by dry absorption. The air to be cleaned is then passed through a flue gas line into which commercial lime hydrate is injected from a metering device arranged above it via a feed line provided with nozzles, the pollutants contained in the exhaust gas reacting with the lime hydrate. The reaction product thus formed sinks into a separator arranged at the end of the flue gas line, from where the reaction material can be removed. Since other chemical products, such as gypsum (CaSO ₄ .2H ₂ O), are formed in the chemical reaction in addition to calcium fluoride, there are considerable difficulties in separating the calcium oxide from the other phases, so that the fluorine is recovered from which fluoride is very complex and therefore expensive. In addition, the flow rate of the system must be set correctly and constantly checked so that in the meantime a drop in the level of the prod ucts is avoided. If the required flow velocity is not maintained, the chimney loses draft. This makes it clear that the reduction of fluorine emission is possible with this system, but it is difficult to achieve in practice.

Furthermore, it is already known that the very toxic carbon monoxide gas can be made catalytically harmless by oxidation to carbon dioxide. For this purpose, the very differently composed mixtures that were produced during the First World War and used in gas masks were used Copper (IΙ) oxide and manganese dioxide, which mostly still contained additions of cobalt oxides and silver oxide. According to Römpp, Chemielexikon, pages 2207/08, such a mixture which is commercially available under the name "Hopcalit" and can actually be regarded as a solid solution, for example composed of 60% MnO ₂ and 40% CuO or also 95% MnO ₂ (from permanganate recovered) and 5% CuO or 50% MnO ₂ , 30% CuO, 15% cobalt oxide and 5% Ag ₂ O. The mixture is used, for example, in the form of brown-black, hard, porous, 2-3 mm large grains in CO filters of gas masks so that they can be used in rooms contaminated with gas from carbon monoxide. The carbon monoxide passing through this mixture is converted catalytically into carbon dioxide at room temperature. The transfer of this known technology to the removal of exhaust gases containing carbon monoxide, for example in those from heating systems and motor vehicle engines, has not hitherto been undertaken in a suitable method because of the high costs involved.

The invention is based on the object of proposing a method with which pollutants, in particular fluorine, but also sulfur dioxide and sulfur trioxide, can be removed from exhaust gases without great expenditure on apparatus. In addition, the method according to the invention should also be able to be used to remove carbon monoxide by oxidation to carbon dioxide in exhaust gases.

This object is achieved according to the invention in that fillers known per se are coated with a slurry which reacts with the pollutants, contains a calcium compound or contains a mixture of metal oxides and serves as a catalyst, to which small amounts of methyl cellulose are added as binders, and coated them Filling bodies are fed to a container through which exhaust gases flow, via an exhaust gas line, the coated filling bodies being shaped and loosely in the container are filled up so that the exhaust gases can easily flow through them.

It is also advantageous that the fillers coated with a slurry containing a calcium compound and loosely filled into a container are used in an exhaust pipe of an industrial plant for the removal of, in particular, fluorine, sulfur dioxide and sulfur trioxide.

In an advantageous development of the invention, the fillers coated with the mixture of metal oxides and serving as a catalyst and loosely filled in the container are inserted into an exhaust gas device for the oxidation of carbon monoxide.

The advantages achieved by the invention consist essentially in the fact that the method according to the invention can be carried out inexpensively without a large apparatus structure and thus less work and that the use of known, saddle-shaped fillers means that the exhaust gas flow is flat over the entire diameter of the container (e.g. with a ceramic sleeve ) is distributed so that there is already a complete reaction of the exhaust gases in the lower part of the container with the coating of the packing and, as a result, the exhaust gas leaves the ceramic filter completely cleaned. As a result of the filling bodies being filled up loosely in the container, a sufficiently free volume between the filling bodies is achieved, so that the required flow rate is possible without the use of a fan. The saddle-shaped packing also offer a very low flow resistance in their packing position, so that the use of fans is also eliminated for this reason.

It is also advantageous that the invention makes it possible to wash off the products obtained in the reaction with the calcium compound without any particular complex separation processes, so that these chemical industries are available again.

In addition, the process according to the invention has the advantage that it enables the very toxic carbon monoxide gas to be removed catalytically by oxidation in carbon dioxide in a simple manner and on a technically larger scale.

Advantageous developments of the invention are solved in subclaims 4 to 17, which essentially relate to the composition of the slurry according to the invention, the shape of the packing, the design of the container, and the composition of the catalyst, its binder and the training of the Straighten the uptake of the saddle-shaped packing coated with the catalyst.

To detect fluorine in the flue gas, iron (III) rhodanide was chosen as the indicator because this compound has a deep red color and its iron is chemically bound in the presence of fluorine in the flue gas, which leads to the decolorization of the indicator. In addition to this indicator with a pH of about 1.5, a second one with the same composition was produced, but which had a pH of about 2.5, in order to avoid the strong carbon dioxide elimination when the first indicator reacted with the calcium carbonate counteract.

The first indicator with a pH of about 1.5 was made from iron chloride FeCl ₃ .6H ₂ O with a mol. of 270.3 and ammonium thiocyanate NH ₄ SCN with one mol. made from 76.1. These two connections react as follows:

FeCl ₃ .6H ₂ O + 3NH ₄ SCN Fe (SCN) ₃ .6H ₂ O + 3NH _c Cl

The following was weighed accordingly:

FeCl ₃ .6H ₂ O mol. Wt. 270.3 500.0 g 3 NH ₄ SCN 3x mol. 228.3 422.3 g

Dest, H ₂ o 800.0 g

1722.3 g About 1500 ml was produced from this batch.

The second indicator with a pH-Wart of 2.5 was made from iron chloride FeCl ₃ .6H ₂ O with a mol. of 270.3 and potassium rhodanide KSCN with one mol. of 97.1. These two connections react as follows:

FeCl ₃ + 3 KSCN Fe (SCN) ₃ . + 3 KCl

The following was weighed accordingly:

FeCl ₃ .6H ₂ O mol. Wt. 270.3 500.0 g

3 KSCN 3x mol. 291, 3 538.8 g

Dest H ₂ O 800.0 g

1838.8 g

To shift the pH, ammonia was also added to the limit of iron precipitation.

About 1600 ml was produced from this batch.

The following examples are intended to explain the method according to the invention in more detail.

example 1

For this experiment, at least Water 4500 g 64% by weight calcium bentonite 2500 g 36% by weight 100% by weight

weighed in. 500 ml of the first indicator with a pH of about 1.5 were added to this sample. Calcium bentonite was stirred into distilled water with constant stirring. The slurry obtained had, according to Lehmann a run-down time of 3 min. The calcium-containing slurry was then colored with the indicator for fluorine. For the coating, the saddle-shaped packing was placed in a conventional pasta sieve and then immersed in the slurry. The coated fillings were then dried on a sand bath and then weighed with the following result:

Coated packing 9400 g filling, uncoated 8600 g coating with calcium bentonite 800 g

500 ml of the first indicator with a pH of about 1.5 were added to this batch. First, the specified amount of calcium chloride was continuously stirred in 400 g of distilled water and then the indicator was added in the specified concentration with the component of calcium bentonite as before. The run-out time of the slurry was 3 minutes 10 seconds according to Lehmann. The saddle-shaped packing was coated as in test 1, then dried and then weighed with the following result:

Coated packing 9100 g filling, uncoated 8200 g coating 900 g

As in Experiment 1, the dried, coated packing elements were filled into the absorption tube to a height of 90 cm and then used in the apparatus. The weighed container of hydrofluoric acid was placed back in the lower 90 ° elbow. After switching on the extraction duct and hair dryer, the observation values listed in Table II were obtained.

The varauch was stopped after 12 minutes and the usability of the indicator used was determined. When the container with the hydrofluoric acid was weighed back, minimal consumption of hydrofluoric acid was found, which led to the conclusion that only the indicator had reacted with the hydrofluoric acid.

Example 2

To increase the calcium antail in this experiment, calcium chloride CaCl _{2 was} first made and the following mixture approach:

Dest. Water 4000 g 57 Gaw .-%

Calcium bentonite 2000 g 23% by weight Calcium chloride 1000 g 14% by weight

100 gaw. -% 500 ml vcm of the first indicator with a pH of about 1.5 were added to this batch. First, the specified amount of calcium chloride was continuously stirred in 400 g of distilled water and then the indicator was added in the specified concentration with the component of calcium bentonite as before. According to Lehmann, the run-out time of the slurry was 3 min 10 sec. The saddle-shaped packing was coated as in test 1, then dried and then weighed with the following result:

Coated filler 9100 g filler, uncoated 8200 g coating 900 g

As in Experiment 1, the dried, coated packing elements were filled into the absorption tube to a height of 90 cm and then used in the apparatus. The weighed container with the hydrofluoric acid was again placed in the lower 90 ° elbow. After switching on the drainage channel and hair dryer, the observation values listed in Table II were given

The experiment was stopped after 12 minutes. By weighing the container with the hydrofluoric acid, a consumption of 143.6 g - 136.5 g = 7.1 g HF was determined. In this experiment the decolorization was slower, which leads to the conclusion that the hydrofluoric acid reacted not only with the indicator but also with the calcium chloride with the formation of white calcium fluoride, which was clearly evident in the decolorization area. The addition of calcium chloride brings little improvement compared to experiment 1,

Example 3 Calcium bentonite and calcium carbonate were used as calcium compounds in this experiment. The mix approach was as follows:

Dest. Water 4000 g 27% by weight

Calcium bentonite 2000 g 29% by weight

Calcium carbonate 1000 g 14% by weight

100% by weight

1000 ml of the first indicator with a pH of about 1.5 were added to this batch. The specified amount of calcium carbonate was then stirred into 4000 g of distilled water with constant stirring and the specified component of calcium bentonite was added. Compared to the In experiment 1, the indicator was added to the mixture in twice the amount since the indicator reacted with the calcium carbonate with the elimination of carbon dioxide. The color of the mixture changed from dark red to brownish, but this change in color had no adverse effect on the usability of the indicator or on the test procedure. The saddle-shaped packing was coated as in the previous experiments, dried and then weighed with the following result:

Coated packing 7400 g packing, uncoated 6800 g coating 600 g

The dried, coated packing elements were refilled into the absorption tube up to a height of 90 cm and then used in the apparatus. The balanced container with the hydrofluoric acid was placed as before in the lower 90 ° elbow. After switching on Abzugskana.l and hair dryer, the observation values listed in Table III were obtained.

The experiment was stopped after 24 minutes. After weighing the container with the hydrofluoric acid, a consumption of hydrofluoric acid of 136.5 g - 124.8 g = 11.7 g was found. From this experiment it was found that calcium carbonate reacted much better with fluorine. After the experiment was discontinued, the decolorization zone went back from 25 cm to a 10 cm wide, white calcium fluoride zone within 15 minutes, which led to the conclusion that in the zone from 10 to 25 cm a reaction had just started while in the 10 cm wide zone, the calcium ions in the coating of the packing reacted completely with the fluorine ions of hydrofluoric acid to form calcium fluoride. The decolorization zone of 10 cm was only reached after 24 min. As can be seen from the following comparison of the experiments carried out to date, a significant improvement in reaction was achieved when using calcium carbonate.

Example 1 after 12 min 50 cm decolorization Example 2 after 12 min 35 cm decolorization Example 3 after 24 min 10 cm decolorization

Example 4 In order to improve the test result even more, only calcium carbonate was used for coating the saddle-shaped packing. For better adhesion of the coating to the packing, a little methyl cellulose in a ratio of 1: 200 to the water content was added as a binder. To counteract the reaction of indicator with calcium carbonate, the second indicator with a pH of 2.5 was used in this experiment. The mix approach for this experiment was as follows:

Distilled water 5000 g 66.5% by weight calcium carbonate 2500 g 33.2% by weight methyl cellulose 25 g 0.3% by weight

100.0% by weight 25 g of methyl cellulose were stirred into the predetermined amount of water while stirring the mixture in order to achieve better adhesion of the coating on the saddle-shaped packing. The specified proportion of calcium carbonate was then added. 500 ml of the second indicator with a pH of about 2.5 were added to the mixture in order to slow the development of carbon dioxide by the pH shift, as already stated. The slurry run-out time was 3 minutes according to Lehmann. The packing was coated and dried in the same way as in the previous experiments. After weighing the coated packing, the following result was obtained:

Coated packing 5490 g packing, uncoated 5240 g coating 250 g

Compared to the previous examples, the coating weight is lower. The dried, coated packing bodies were filled up to a height of 90 cm as before into the absorption tube, the container was weighed with the hydrofluoric acid and placed in the 90 ° elbow. After switching on the extraction duct and hair dryer, the observation values given in Table IV are obtained.

The experiment was stopped after 60 minutes. After weighing the container with the hydrofluoric acid, a consumption of hydrofluoric acid of 175.0 g - 148.5 g = 26.5 g was found. In this experiment, the same width of the decolorization zone as in the previous example was only achieved after more than twice the time. This experiment showed that calcium carbonate binds the fluorine best. The decolorization zone was white, which was certainly considered calcium fluoride.

Example 5 In order to further improve the test result obtained from Example 4, the following mixture was made:

Dest. Water 4500 g 49.9% by weight calcium carbonate 4500 g 50.0% by weight methyl cellulose 10 g 0.1% by weight

100.0% by weight

500 ml of the second indicator with a pH of about 2.5 were added to this batch. This approach made the slurry thicker. 10 g of methyl cellulose were added to the specified water content while whisking in order to achieve better adhesion of the coating to the saddle-shaped packing. The proportion of methyl cellulose was reduced compared to the experiment in Example 4, so that the packing could be cleaned more easily after use in the apparatus and before it was loaded again. After adding the methyl cellulose to the water content, the prescribed amount of calcium carbonate was stirred in and the second indicator was added, as already indicated. The Lehmann expiration time was almost 5 minutes. The mixture could not be made any more viscous, since otherwise the packing elements in the sieve could no longer be coated sufficiently. The saddle-shaped packing was coated as in Experiment 1, then dried and then with the following result weighed:

Coated packing 6400 g packing, uncoated 5600 g coating 800 g

As in the previous experiments, the dried, coated packing was placed in the absorption tube and then inserted into the apparatus. The hydrofluoric acid was weighed out with the container as before. After switching on the ventilation duct and hair dryer, the observation values listed in Table V were obtained.

The experiment was stopped after 3 hours. A waiting period of 24 hours was waited for the exact measurement of the white zone, which consisted of calcium fluoride. The white zone had a length of 8 cm, only in this Zone Ka lzi formed around u u id. The overlying filler bodies had not come into contact with fluorine, which revealed an examination of the filler bodies after they had been poured out. A washing test carried out after the absorption tube had been removed from the apparatus showed that the packing was easier to wash off, with 10 liters of water being sufficient to clean the packing from the adhering coating. Overall, this experiment gave an optimal result. After weighing the container with the hydrofluoric acid, a consumption of hydrofluoric acid of 195.5 g - 117.4 g = 78.1 g was found. After tests 4 and 5, the consumption of hydrofluoric acid was about 26 g per hour. The white zone made of calcium fluoride with the redness above it can be clearly recognized by the absorption tube shown in FIG. 2.

X-ray diffraction revealed that fluorine had not passed the decolorization zone. For this purpose, a sample was taken from the white zone and another from the packing elements above. The X-ray diffraction pattern clearly showed reflections of calcium fluoride and besides, in a weakened form, reflections of calcium carbonate, from which it could be concluded that not all of the calcium carbonate was present in this zone either. with f luor react Ie rI hall e. this zone was therefore able to dazzle even more.

The X-ray diffraction diagram of the coating substance of the packing from the red zone (upper packing layers) showed only reflections of calcium carbonate. This led to the safe conclusion that the fluorine had not penetrated into these zones and thus completely reacted in the lower white zone.

The air led into the exhaust duct was examined for hydrogen fluoride using a Dräger tube. The scale of the tubes ranged from 1.5 to 15 ppm HF. Despite repeated measurements, no discoloration of the tubes was found , which showed that there was no longer any hydrogen fluoride in this air, so that it had been completely absorbed by the coating of the filling bodies.

To determine whether the 38-40% hydrofluoric acid concentration changed during the course of the experiment, 1N NaOH titrations were carried out, using methyl red as an indicator.

38 - 40% HF in delivery condition:

36.70 g HF with container 18.80 afterwards 35.85 g container 3.21 before

0.85 g HF 15.59 ml consumption 1N NaOH

18.30 ml of 1N NaOH were consumed for 1 g of HF.

35.67 g HF with tube 33.53 stand after

35.89 g jar 18.99 prior to

0.78 g HF 14.54 ml consumption 1 n NaOH

18.64 ml of 1N NaOH were consumed for 1 g of HF. The mean was 18.47 ml 1N NaOH for 1 g HF.

38 - 40% HF after the test run:

37.93 g HF with tube 38.00 stand after

35.81 g jar 3.69 as before

2.07 g HF 34.31 ml consumption 1N NaOH

16.57 ml of 1N NaOH were consumed for 1 g of HF.

37.52 g HF with tube 28.31 stand after

35.86 g jar 0.55 as before

1.56 g HF 27.75 ml consumption 1N NaOH

15.72 ml of 1N NaOH was consumed for 1 g of HF. The mean was 16.65 ml 1N NaOH for 1 g HF, The results of the titrations clearly showed that the concentration of hydrofluoric acid decreased, which was in agreement with the results of the tests in examples 1 to 5 and was also clearly underlined by the X-ray analyzes.

Based on the data from a subsequent exhaust gas analysis with

Volume 6757 m ³ / h

Temperature 146 ° C

Speed 9.56 m / s

F 0.083 kg / h

SO ₂ 0.042 kg / h

Cl below 9 kg / h

SO ₂ 1.9 vol.%

to the values obtained in exemplary embodiment 5, the following calculation resulted:

Total weight of the 38 - 40% Hf 1123 g / Ltr.

HF weight 425 g / Ltr.

Consumption in Example 5 78.1 g

HF weight from Example 5 29.6 g

Volume of the white zone from Example 5 628.3 cm ³

Initial amount of CaCO ₃ in this zone is 71.1 g

Incident F amount according to the flue gas example 1992 g / day

Absorption volume 42283 cm ³ required for this

The amount of CaCO ₃ required for this was 4784.9 g

From this data it can be seen that the invention

Process fully meets the requirements of practice. For example, a volume of 1m ^{3 of} coated, saddle-shaped packing material could be produced within 24 days bind all of the fluorine in the flue gas analysis given above, for which the specified volume of the packing would have to be coated with about 113 kg of calcium carbonate.

Further tests have shown that the process according to the invention can also be used in the same way for eliminating other pollutants in exhaust gases, for example SO ₂ or SO ₃ , since the calcium carbonate added binds these exhaust gas components to calcium sulfite or calcium sulfate.

This has the very significant advantage that serious environmental damage caused by such aggressively operating media is considerably reduced or can even be completely eliminated. Historically valuable buildings and other cultural monuments can be protected from major corrosion damage using the method according to the invention.

According to the invention it is further provided that known, saddle-shaped fillers are coated with a known mixture consisting of metal oxides, serving as a catalyst, together with a small proportion of methyl cellulose, whereby according to one embodiment of the invention, methyl cellulose is used as a catalyst, which consists of metal oxides Mixture is preferably added in a ratio of 1: 100.

According to the invention, the coated packing elements are held in a container through which exhaust gases can flow and which, according to a further development of the invention, can be closed on both sides by a wire mesh. Such a container is inexpensive to manufacture and, with the coated, saddle-shaped packing elements, can easily be arranged in an exhaust gas device, for example in an exhaust pipe of heating systems or in an exhaust pipe of motor vehicle engines.

The oxidation of carbon monoxide to carbon dioxide takes place Complete catalytically only if there is still some oxygen in the exhaust air. This is achieved in that a flap is attached to the exhaust pipe in heating systems, so that air can also be sucked in through this. For the same reason, an additional air supply must be provided for motor vehicle engines.

As can be seen from the process according to the invention, the packing elements coated with metal oxides and the packing elements coated with the slurry containing a calcium compound must each be kept in separate filling devices so that the fully reacted calcium coating on the packing elements can be washed off and their reaction products can be collected for reuse. and that the coating consisting of metal oxides, which is applied to the packing and serves as a catalyst, is not consumed and is therefore available for further oxidation of the carbon monoxide.

All individual and combination features disclosed in the description and the claims are regarded as essential to the invention.

Claims

Patent claims

1. A process for the removal of pollutants from exhaust gases, characterized in that fillers known per se with a slurry containing a calcium compound which reacts with the pollutants or a mixture consisting of metal oxides and serving as a catalyst, to which small amounts of methyl cellulose are added as binders , coated and the fillers coated in this way are fed to a container through which exhaust gases flow, via an exhaust gas line, the coated fillers being shaped and filled loosely in the container in such a way that the exhaust gases can easily flow through them.

2. The method according to claim 1, characterized in that the coated with a slurry containing a calcium compound, loosely filled in a container filler in an exhaust pipe of an industrial plant for the removal of fluorine, sulfur d i ox id and sulfur trioxide are used in particular.

3. The method according to claim 1, characterized in that the coated with the mixture of metal oxides, serving as a catalyst, loosely filled in the container filler are used in an exhaust device for the oxidation of carbon monoxide.

4. The method according to claim 1 and 2, characterized in that the packing after reaction of their calcium compound contained in the coating with Schadstoffantei len removed from the exhaust pipe and at the same time re-coated packing are used, the fully reacted coating of the packing is washed off and their reaction products are collected, and that these reaction products are pressed into filter cakes in a filter press.

5. The method according to claim 1, 2 and 4, characterized in that the calcium compound of the slurry is selected from the group of calcium carbonate, calcium bentonite and calcium chloride.

6. The method according to claim 1, 2 and 3 to 5, characterized in that calcium carbonate is preferably added to the slurry.

7. The method according to one or more of claims 1, 2 and 3 to 6, characterized in that up to 50 percent by weight calcium carbonate is added to the slurry.

8. The method according to one or more of claims 1, 2 and 3 to 7, characterized in that the water content in the slurry is up to 66 percent by weight.

9. The method according to one or more of claims 1, 2 and 3 to 8, characterized in that the slurry methyl cellulose is added in a ratio of 1: 200 or 1: 450 to the water content.

10. The method according to one or more of claims 1, 2 and 3 to 9, characterized in that an indicator with a pH of about 1.5 or 2.5 is added to the slurry.

11. The method according to claim 10, characterized in that the slurry is added as an indicator iron (III) rhodanide.

12. The method according to claim 1, characterized in that the packing is saddle-shaped to increase the surface in the reaction area.

13. The method according to claim 1 and 11, characterized in that the complete reaction of the coating of the packing with the Schadstoffantei len from the exhaust pipe with organic dyes or electrodes is determined.

14. The method according to claim 1 and 3, characterized in that the mixture serving as a catalyst essentially contains copper (IΙ) oxide and Man gand i ox id and ie additions of Koba ltox id en and S il berox id, the concentrations the metal loxides are known.

15. The method according to claims 1, 3 and 14, characterized in that the binder methyl cellulose is added to the catalyst consisting of metal oxides in a ratio of 1: 100.

16. The method according to one or more of claims 1 to

15, characterized in that the fillers are filled in a container made of ceramic as a supporting grid.

17. The method according to one or more of claims 1 to

16, characterized in that the container consists of metal and is closed at both ends with a net, preferably made of wire.