WO1989011329A1

WO1989011329A1 - Agent and process for cleaning gases and exhaust gases and process for producing said agent

Info

Publication number: WO1989011329A1
Application number: PCT/EP1989/000534
Authority: WO
Inventors: Roland Fichtel
Original assignee: Roland Fichtel
Priority date: 1988-05-16
Filing date: 1989-05-16
Publication date: 1989-11-30
Also published as: EP0377010A1; DE3915934A1; DE3915934C2

Abstract

Surfactants such as activated charcoal, brown coal open-hearth coke, activated alumina and silica gel are admixed, in finely divided form, with the water required for slaking quick lime. The Ca(OH)2 obtained is particularly suitable for removing Hg from gases and exhaust gases. Residual HCl, SO2 and NOx can also be removed. The surfactants can also be admixed with the quick lime before slaking or with the Ca(OH)2. The surfactants may be charged with catalytically active heavy metals, e.g. vanadium, or with substances which bind heavy metals, e.g. sodium sulfphide. The surfactants used are activated charcoal, brown coal open-hearth coke, silica gel, diatomaceous earth and/or activated alumina.

Description

Agents and processes for the purification of gases and exhaust gases and a process for producing these agents

description

The invention relates to an agent and a method for cleaning gases and exhaust gases and a method for the production of these agents.

Industrial activity in the field of energy _. Casting, the processing of substances, for example the smelting of ores, the incineration of waste and the conversion of substances leads to gases or exhaust gases which can be contaminated with pollutants in different amounts.

The pollutants of importance include hydrogen chloride, hydrogen fluoride, sulfur dioxide, nitrogen oxides, carbon monoxide, heavy metals in volatile form, dioxins, furans, chlorinated hydrocarbons, polycyclic aromatic hydrocarbons and the like, ie ecotoxic pollutants.

In practice, a wide variety of methods are used to separate these substances from the gas streams. They almost always consist in cooling the gases and washing the listed pollutants out of them with water or suitable solutions.

These washing processes are quite effective, but not without problems. In most cases, they are extremely expensive. In addition, there are also residues in the clean gas the pollutants remain in different concentrations.

Elemental mercury is one of the substances that cause problems owing to their high volatility. The polychlorinated dibenzodioxins and dibenzofurans, which are considered harmful even in the smallest concentration, can be found in almost all gases according to conventional cleaning systems. The polycyclic hydrocarbons (PAH) and numerous chlorinated hydrocarbons (C1K), e.g. Chloromethane, tri and per.

Added to this is nitrogen monoxide, the separation of which requires complex processes.

Activated carbon or activated coke is already used to remove the residual contents of acidic pollutants, chlorinated hydrocarbons, polycondensed aromatic hydrocarbons, volatile heavy metals and also NO with NH3 from exhaust gas streams. The usual way of working is to pass the pre-cleaned exhaust gas over activated carbon fixed bed reactors or moving bed reactors. The operating temperature is 80-150 degrees C.

This method of operation is effective when an exhaust gas is used which contains only low levels of sulfur dioxide, HC1 and dust, which requires efficient, upstream exhaust gas cleaning.

A further disadvantage is that the coal can self-ignite in the activated carbon reactors. This is the case in particular in the event of operational downtimes.

The control of the smoldering fire nests in a fixed bed reactor is difficult and time-consuming. It is also not without problems to inject activated carbon directly into the exhaust gas stream or suspended in milk of lime.

Activated carbon accumulations can occur in the reaction product, which give rise to smoldering fires in activated carbon nests in the intermediate storage containers. Furthermore, the uniform distribution of the activated carbon in the exhaust gas stream causes problems during direct injection.

The uniform suspension of activated carbon in the calcium hydroxide suspension is also not easy and gives rise to fluctuating separation rates, so that compliance with the limit values is problematic.

In addition, it has been shown that the separation efficiency in quasi-dry exhaust gas purification processes (injection of milk of lime and evaporation of the water) in the temperature range above 170 ° C. is insufficient. Good separation performance is achieved in the range of 120-130 degrees C. At these temperatures, however, there is always the risk that the fabric filters required for effective solid separation will become encrusted.

According to the above, there is a need for an improved exhaust gas purification method that

- in the temperature range above 170 degrees C has sufficient separation capacities for volatile heavy metals, in particular mercury, chlorinated hydrocarbons (dioxins and PCB's) and polycondensed aromatic hydrocarbons (PAH's),

a safe and uniform mixing of the exhaust gas stream and the surface-active substances is guaranteed, - Prevents the self-ignition of activated carbon / activated coke after use, and

- A NOx reduction without prior extensive separation of S02, HC1 and dust is guaranteed.

Furthermore, an operationally simple and inexpensive method is sought.

The invention solves these problems by a means for cleaning gases and exhaust gases according to the independent patent claim 1. Preferred further developments of the agent are described in the dependent claims 2 to 8.

The invention further provides a method for producing dry powders based on calcium hydroxide for gas and exhaust gas purification according to independent claim 9. Preferred developments of these methods are described in the dependent 10-15 patent claims.

According to a further aspect of the invention, methods for purifying gases and exhaust gases are proposed, which are described in the independent patent claims 16, 20 and 21. Preferred embodiments of these methods can be seen from the dependent claims.

According to the invention, the object is achieved in two stages in that, in a first stage, reactive calcium hydroxides are prepared which contain surface-active substances which, in a second stage, are used to act on the pollutants of exhaust gases in a dry process , and be separated again from the exhaust gas stream. The process according to the invention for producing reactive calcium hydroxide for gas and exhaust gas purification is characterized in that surface-active substances are added to the quicklime before the quicklime is extinguished, to the extinguishing water during the extinguishing and to the calcium hydroxide after the extinguishing.

In particular, silica gel, diatomaceous earth, activated aluminum oxide, activated carbon and or hearth furnace lignite coke in powder form are used as surface-active substances.

These are various types of substances which are characterized by a large surface area, based on their weight. The average active surface for activated carbon is around 600 m2 / g. The pollutants are deposited on these active surfaces, in particular mercury, dioxins, PCßs, but also to a certain extent S02, HC1 and NOx. These substances remain there or ^~ can be converted into other substances.

For the purposes of the invention, the surface-active substances are used as powders.

The surface-active substances have a grain size, determined as a sieve passage, of <200ug. A grain size which corresponds to that of calcium hydroxide powder is preferred.

The process according to the invention can also advantageously be carried out by subjecting the powdery surface-active substances to catalysts for oxidation, reduction and / or decomposition reactions before they are used for the treatment of gases and exhaust gases. The application takes place in such a way that the corresponding heavy metals are applied to the surface-active substances as water-soluble salts or dissolved in organic solvents, and the surface-active substances are then subjected to drying. In addition to the active surfaces, there are also catalysts for a wide variety of reactions on the surface-active substances.

Instead of aqueous solutions of heavy metals, alcoholic solutions can also be used.

The following heavy metals are particularly suitable for the process according to the invention:

Iron, nickel, cobalt, chromium, manganese, vanadium, titanium, molybdenum, tungsten, copper, tin, palladium, platinum, gold, and / or zinc. In most cases, these heavy metals are used as salts. Applied to the surface-active substances, they can also be converted into higher oxidation levels by oxidation or into lower oxidation levels or even in elemental form by reduction.

Water-soluble chlorides and nitrates are predominantly used as salts.

The heavy metal binding substances are water-soluble sulfides, e.g. Sodium sulfide and mercaptans, or trimercapto-s-triazine for use.

The combination of the activated carbon provided with heavy metals with calcium hydroxide has a multiple function.

The presence of the inorganic substance reduces the risk of burning the active carbons loaded with heavy metals. Effective inhibition occurs when calcium hydroxide as a fine powder together with the Activated carbons are present.

The risk of ignition can be suppressed particularly strongly if the activated carbons are mixed together with quicklime and then subjected to an extinguishing reaction, so that activated carbon and calcium hydroxide are present in very fine distribution, in some cases. Calcium hydroxide is deposited in the pores of the activated carbon.

A further embodiment of the production of the reactive calcium hydroxides consists in mixing the surface-active substances with quicklime and adding the pollutant-binding and / or catalytically active substances to the extinguishing water.

It is also within the scope of the invention that calcium hydroxide and surface-active substances are mixed, the latter possibly. are acted upon by catalytically active and / or heavy metal-binding substances.

A special embodiment of the production of reactive calcium hydroxides according to the invention consists in using surface-active substances which have a catalytic effect with heavy metals which have an effect on oxidation or reduction processes, and with substances with a basic effect, such as sodium hydrogen carbonate, sodium carbonate, sodium hydroxide and the like. are acted upon. With this combination of heavy metals and basic compounds on surface-active substances, oxidation and reduction processes can be controlled via potential changes.

The same applies to acids which are applied to the surface-active substances together with the catalytically active heavy metals. The acids also act on the heavy metals with regard to the form of the compound and redox potential. The calcium hydroxides containing surface-active substances produced according to the invention are used in the process according to the invention for cleaning exhaust gases.

The process according to the invention for the purification of gases and exhaust gases from acidic pollutants, such as hydrogen chloride, hydrogen fluoride, sulfur dioxide, hydrocyanic acid and the like, nitrogen oxides, hydrocarbons, chlorinated hydrocarbons, organic compounds and volatile heavy metals, e.g. Mercury, arsenic, antimony, cadmium and thalium, using surface-active substances, is characterized in that finely powdered, dry calcium hydroxide is added to the gas or exhaust gas stream, which contains surface-active substances such as activated carbon, lignite Oven coke, silica gel, silica and / or active aluminum oxide contains, added and mixed with the exhaust gas stream in a reactor and the calcium hydroxide powder with the bound pollutants without lowering the reaction temperature on dust separating devices, in particular on fabric filters or electrostatic precipitators from which gas flow is separated.

The procedure outlined has considerable advantages.

The intimate mixing of calcium hydroxide and surface-active substance makes it possible to distribute the small amounts of surface-active substance evenly in the exhaust gas, since considerable amounts of Ca (0H) 2 have to be used.

A drop in temperature, e.g. from 200 to 120 degrees C, as is practiced, is not necessary in order to remove dioxins, PAHs and mercury as far as possible.

Self-ignition of activated carbons containing heavy metals no longer plays a role. Since a mixture of less than 1055 activated carbon and more than 90% Ca (0H) 2 is generally is set, the problem of spontaneous combustion and the smoldering fire of dormant materials does not exist.

Calcium hydroxides, which have been produced from quicklime, mixed with surface-active substances, are particularly resistant to separation.

Pneumatic devices are preferably used to inject the modified calcium hydroxides.

The mixing of the modified calcium hydroxides with the exhaust gas takes place in reactors which ensure good mixing by means of deflection internals.

The used Ca (0H) 2 is preferably separated on fabric filters. E-filters are also suitable.

Returning the used material to the reactor for better utilization of Ca (0H) 2 and the surface-active substances presents no difficulties.

It is of considerable importance that activated carbon / activated coke also acts as a catalyst for reducing NOx with NH3 to N2.

It is also within the scope of the invention to mix the surface-active substances in a mixture with powdery, non-combustible, inorganic substances such as limestone powder, quicklime, carbonation sludge in finely powdered form, dolomite, sand, red earth, quartz powder, diatomaceous earth and / or aluminum use oxide instead of calcium hydroxide.

This embodiment of the invention is suitable when no or little acidic pollutants are present in the exhaust gas, that is to say that the expensive basic Ca (0H) 2 can be dispensed with. The treatment of the exhaust gas with the surface-active substances takes place in the temperature range of 20-1200 degrees C, preferably in the range of 80-250 degrees C, in particular in the range of 170-240 degrees C, more preferably in the temperature range from 180-220 degrees C.

The water content of the exhaust gas is decisive for the choice of temperature. The lowest temperature limit should be 30 to 40 degrees C above the dew point. When using Ca (0H) 2 and HC1 in the exhaust gas, the temperature should not drop below 130 to 140 degrees C, since otherwise encrustations occur on the tissue filter.

An advantageous form of the process according to the invention is that in a multi-stage process the gases and exhaust gases are first subjected to dry or wet cleaning and then for the residual separation of the inorganic and organic pollutants the gases and exhaust gases with substances which contain surface-active substances. if necessary are treated with heavy metals, are treated, in order to reduce nitrogen oxides in the gas stream prior to treatment with the surface-active substances, ammonia or suitable nitrogen-containing compounds, e.g. Urea are added.

The heavy metals to the surface-active substances ha¬ the function ben the oxidation of S02 to S03, C0 to C02, NO to N02 and Sieren hydrocarbons to C02 and H20 to catalytically ^".

The oxidation of sulfur dioxide to sulfur trioxide has the advantage that the more volatile sulfur trioxide is formed from the volatile sulfur dioxide, which is preferably deposited on the surface-active substances. If the surface-active substances are used together with basic substances, be it lime or calcium hydroxide, then immediate implementation with these basic substances is also possible. Particularly favorable catalysts for this are manganese, vanadium, iron and platinum.

A further possibility is to convert the carbon monoxide which is always present in the exhaust gases into harmless carbon dioxide using the catalysts and the oxygen present. The same applies to the large number of unburned hydrocarbons present in small amounts, which can also be oxidized under the catalytic influence of the heavy metals applied to the surface-active substances.

The chlorinated or sulfur-containing hydrocarbons can also be oxidized to the basic compounds C02, H20, HC1 and / or S02 in residual contents and thus removed as ecotoxic pollutants.

Chromium, vanadium, iron, palladium, copper and manganese are particularly suitable for the oxidation of organic substances.

The same applies to nitrogen monoxide, which can be converted to nitrogen dioxide with the action of catalysts, in particular chromium, titanium, iron and manganese. This is water-soluble and can be washed out of the exhaust gas stream. On the other hand, however, it can be converted into non-volatile salts immediately in the presence of basic substances.

The reduction of nitrogen oxide with ammonia or nitrogen-containing compounds, e.g. Urea is favored by the heavy metal catalysts.

The effect of the oxidation catalysts for sulfur dioxide and also for nitrogen oxide can be increased if the surface-active substances together with the heavy metals also have basic-acting substances, for example sodium hydroxide, sodium carbonate, sodium bicarbonate, etc. be worn. As the oxidation takes place in the direct vicinity of the basic substances, the higher oxides of sulfur and nitrogen can be integrated immediately.

This method of operation is particularly important when the method according to the invention is used for the residual removal of acidic pollutants.

If the gases and exhaust gases have been pre-cleaned, the surface-active substances can preferably be used for residual cleaning. This applies in particular to organic substances and also to the residual levels of hydrogen chloride and sulfur dioxide.

The process is particularly important for the deposition of nitrogen oxides. The conventional cleaning methods do capture hydrogen fluoride, hydrogen chloride and sulfur dioxide to a sufficient extent, but are only able to separate the nitrogen oxide to a small extent. The subsequent cleaning with the aid of surface-active substances to which catalysts have been applied means that nitrogen oxide can either be oxidized and then separated with basic substances, or reduced to nitrogen with ammonia.

The use of the surface-active substances charged with heavy metals in combination with Ca (0H) 2 or inorganic dusts is of course not restricted to use in a post-cleaning stage, but also includes the initial use. The method according to the invention is for the treatment of gases and exhaust gases from power plants, from waste incineration plants, from special waste incineration plants, from combustion plants, from plants for the production of glass and ceramics, from plants for remelting old aluminum and also for treating gases and exhaust gases from numerous production processes, e.g. . B. the smelting of ores, and other industrial processes, can be used.

It is of particular importance in the cleaning of pre-cleaned gases and exhaust gases if the surface-active substances as powder, in combination with inorganic dusts, predominantly Ca (0H) 2, if necessary. loaded with heavy metals, blown into the gas stream and then deposited on appropriate filters.

Example 1 :

28 g quicklime was extinguished with 15.2 g water by suspending 1.4 g activated carbon with 700 m2 / g active surface. A gray powder resulted, which had good flowability.

A gas was passed over 252 mg of this substance in a solid layer at a temperature of 149 degrees C, which had the following characteristics:

- Moisture 0.26 g / 1

- HCl content 22.5 mg / 1

HgC12 content 1.29 µg / l

A total of 11.2 liters were passed over the modified Ca (0H) 2.

Of a total of 14.4 µg HgC12, 76.5% was absorbed in the activated carbon. This example shows that when slaked lime is extinguished in the presence of activated carbon, a reactive Ca (0H) 2 is formed which can be used in exhaust gas cleaning for effective mercury removal.

Example 2:

28 g of quicklime was mixed with 3.7 g of brown coal hearth coke as coke dust and then quenched with 17 ml of water. The gray, anhydrous calcium hydroxide was tested for its suitability as a sorbent for exhaust gas cleaning.

About 296 mg of this product were passed at 187 degrees C 10.8 l of an exhaust gas of the following composition:

- nitrogen 80 vol.-5.

- Oxygen 20 vol.-SS

- Moisture 278 mg / 1

- HC1 11.7 mg / 1

- HgC12 0.62 µg / 1

6.3 µg of HgC12 was deposited on the sorbent, i.e. 87% were absorbed.

This example shows that brown coal hearth furnace coke in combination with Ca (0H) 2 is suitable for mercury separation.

Example 3:

5 g of cement powder were mixed with 0.25 g of brown coal hearth coke.

Over 280 mg of this product were passed at 188 ° C 10.3 l of an exhaust gas of the following composition: Nitrogen 80 vol.- »

Oxygen 20 vol.- »

Moisture 294 mg / 1

HC1 12.4 mg / 1

HgC12 0.7 µg / 1

4.7 µg of HgC12 was deposited on the sorbent coke, i.e. 66 »were absorbed.

Lignite hearth coke in combination with inert material is also suitable for mercury separation from exhaust gases.

Example 4:

An exhaust gas of the above composition was passed over 260 mg of lignite hearth coke at 190 degrees C.

Of 7.2 µg HgC12, 7 µg HgC12 was retained on the sorbent, i.e. 97 »were absorbed.

Example 5:

5 g Ca (0H) 2 were mixed with 0.25 g fine powder A1203. Over 280 mg of this mixture were passed at 192 degrees C 10.3 l of an exhaust gas of the following composition:

- nitrogen 80 vol.- »

- oxygen 20 vol.- »

- Moisture 295 mg / 1

- HC1 12.4 mg / 1

- HgC12 0.7 µg / 1 A total of 3.6 µg of 7.2 µg HgC12 was absorbed, ie 50 »deposited.

A1203 is therefore suitable as a sorbent for the separation of mercury from exhaust gases.

Example 6:

The waste gas from a waste incineration plant was dry cleaned with Ca (0H) 2 at 200 degrees Celsius. To remove mercury, the content of which in the raw gas was 330 µg / m3, 25 kg of Ca (0H) 2 and 1.25 kg of lignite-hearth furnace coke dust were blown in per ton of waste, mixed in a reactor and separated on a fabric filter. Ca (0H) 2 and coke dust had been mixed beforehand.

Only 90 µg / m3 was measured in the clean gas after the fabric filter. This is a reduction of the mercury content by more than 50 ».

Claims

EXPECTATIONS

1. Means for cleaning gases and exhaust gases consisting of a dry powder based on reactive calcium hydroxide with a content of 0.05-50% by weight, preferably 1-20% by weight. surfactants.

2. Composition according to claim 1, characterized by a content of the surface-active substances of 2.5 - 7 wt. ».

3. Composition according to claim 1 or 2, characterized by a grain size of <200 / um.

4. Agent according to one of the preceding claims, characterized ge indicates that the surface-active substances are selected from the group activated carbon, lignite-Herdofen¬ coke, aluminum oxide, diatomaceous earth and / or silica gel.

5. Composition according to one of the preceding claims, marked by a content of 0.1-15% by weight, preferably 2.5

7 wt. » of catalytically active heavy metals and / or pollutant-binding substances.

6. Composition according to claim 5, characterized in that the surface-active substances with the catalytically active heavy metals and / or pollutant-binding substances are opened.

7. Composition according to claim 5 or 6, characterized in that the pollutant-binding substances are selected from the group sodium sulfide, mercaptans and trimercarpto-s-triazine and that the catalytically active heavy metals are selected from the group of vanadium, tungsten, molybdenum , Manganese, iron, nickel, cobalt, chromium, copper, tin, zinc and / or titanium compounds.

8. Composition according to claim 5 or 6, characterized in that the surface-active substances are acted on with basic substances, in particular sodium bicarbonate, sodium carbonate and / or sodium hydroxide.

9. A process for the production of dry powders based on calcium hydroxide for gas and exhaust gas purification according to one of the preceding claims, characterized in that the quicklime and / or during the extinguishing of the extinguishing water and / or after the extinguishing of quicklime Extinguishing agents are added to the calcium hydroxide.

10. The method according to claim 9, characterized in that activated carbon, lignite hearth coke, aluminum oxide, Kiesel¬ gur and / or silica gel are used finely divided.

11. The method according to claim 10, characterized in that the surface-active substances with catalytically active heavy metals and / or pollutant-binding substances are applied before the extinguishing process is carried out.

12. The method according to claim 11, characterized in that the surface-active substances before extinguishing with heavy metal-binding substances, for example sodium sulfide, mercapanes and / or trimercapto-s-triazine, and / or catalytically acting heavy metals, such as vanadium, tungsten, molybdenum, manganese, iron, nickel, cobalt, chromium, copper, tin, zinc, and / or titanium compounds are acted on as catalytically active substances.

13. The method according to claim 9, characterized in that surface-active substances, such as activated carbon, brown coal hearth coke, aluminum oxide, silica gel, diatomaceous earth and the like. mixed with the quicklime and then the extinguishing process is carried out, the extinguishing water containing the pollutant-binding and / or catalytically active substances.

14. A process for the preparation of reactive calcium hydroxides for gas and exhaust gas purification, characterized in that the calcium hydroxide has surface-active substances, such as activated carbon, lignite hearth coke, aluminum oxide, silica gel and the like. are admixed, which are optionally treated with catalytically active and / or heavy metal-binding substances.

15. The method according to any one of the preceding claims, da¬ characterized in that surface-active substances are used which with heavy metals, which have a catalytic effect on oxidation and reduction processes, and with basic-acting substances such as sodium bicarbonate, sodium carbonate, sodium hydroxide and the like . have been charged.

16. Process for the purification of gases and exhaust gases from acidic gases, such as hydrogen chloride, hydrogen fluoride, sulfur dioxide, hydrocyanic acid and the like, nitrogen oxides, hydrocarbons, chlorinated hydrocarbons, organic compounds and volatile heavy metals, in particular mercury, arsenic, antimony, cadium and thallium, characterized in that finely pulverized, dry calcium hydroxide is added to the gas or exhaust gas stream, the surface-active substances, in particular activated carbon, lignite Hearth furnace coke, silica gel, kieselguhr and / or active aluminum oxide contains, added and mixed with the exhaust gas stream in a reactor and the calcium hydroxide powder with the bound pollutants without lowering the reaction temperature on dust separating devices, in particular on fabric filters or electrostatic filters is separated from the gas stream.

17. The method according to claim 16, characterized in that the finely powdered calcium hydroxides prepared according to claims 9-15 and containing surface-active substances are used.

18. The method according to claim 16, characterized in that the activated carbons loaded with heavy metals together with powdery, non-combustible, inorganic substances, such as limestone powder, quicklime, carbonation sludge in fine powder, dolomite, sand, red earth, quartz powder, diatomaceous earth and / or Aluminum oxide can be used instead of calcium hydroxide.

19. The method according to any one of claims 16-18, characterized ge indicates that the treatment of the exhaust gas with the surface-active substances in the temperature range of 20-1200 degrees C, preferably in the range of 80-250 degrees C, especially in the range of 150-240 degrees C, more preferably in the temperature range of 170-220 degrees C.

20. Process for the purification of gases and exhaust gases from inorganic and / or organic pollutants, characterized in that in a multi-stage process the gases and exhaust gases are first subjected to dry or wet cleaning and then for the residual separation of the inorganic and organic Pollutants the gases and exhaust gases are treated with substances that contain surface-active substances that may have heavy metals on them. Production of nitrogen oxides, ammonia or suitable nitrogen-containing compounds, in particular urea, are added to the gas stream before the treatment with the surface-active substances.

21. Process for the purification of gases and exhaust gases from inorganic and / or organic pollutants in a multi-stage process, characterized in that the gases and exhaust gases in the first stage with powdered surface-active substances which are acted upon by oxidation catalysts, together with powdered ones basic substances, e.g. Calcium hydroxide, with the oxidation of sulfur dioxide to sulfur trioxide and if necessary. Treated from nitrogen monoxide to nitrogen dioxide and in a second stage with surface-active substances, which with catalysts for the reduction of nitrogen oxides with ammonia or nitrogen-containing compounds, for. B. urea, in the presence of inorganic dusts, e.g. Limestone powder, brought into contact, can be separated from the exhaust gas stream in a reactor for reaction and on a fabric filter or e-filter.

22. The method according to claim 21, characterized in that the two stages are followed by a third stage with surface-active substances for residual separation of inorganic and / or organic substances, which is designed as entrained-flow reactor or as a solid layer.