WO2017067534A1

WO2017067534A1 - Biologically-chemically reactive method for waste-air cleaning

Info

Publication number: WO2017067534A1
Application number: PCT/DE2016/100254
Authority: WO
Inventors: Walter Hilgert; Christian Richter
Original assignee: Rietzler Gruppe GmbH; Ugn-Umwelttechnik Gmbh
Priority date: 2015-06-01
Filing date: 2016-06-01
Publication date: 2017-04-27
Also published as: DE112016002454A5; DE102015118103A1

Abstract

The invention relates to a method for cleaning sulphide-containing and optionally hydrocarbon-containing waste-air mixtures, with steps as follows: passing the waste-air mixture through at least one chemical-biological reactive filter comprising: porous scaffold material particles with inorganically bonded natural fibres and pH-buffering support material, at least one iron compound, sulphatoclastic and optionally hydrocarbon-degrading organisms, and additives; and drawing off the waste-air stream, cleaned in the at least one reactive filter, from the chemically-biologically active reactive filter, and also to the use of a biological reactive filter material comprising a scaffold material populated with sulphatoclastic and optionally hydrocarbon-degrading organisms for cleaning sulphide-containing and/or hydrocarbon-containing waste air, such as biogas, hydrolysis gas, landfill gas, sewage-treatment plant gases, fermentation gas, pyrolysis gas, wood gas, gases from composting facilities, pit gas, mine gas, gases from geothermal wells and deep wells; synthesis gas, petroleum-associated gases, natural gas, acid gas, lean gas; production off-gases from the pharmaceutical and food industries, such as the waste air from oil mills.

Description

BIOLOGICAL-CHEMICAL REACTIVE METHOD FOR EXHAUST CLEANING

The invention relates to a biochemically reactive process for the environmentally friendly purification of sulfide and / or hydrocarbon-containing exhaust air mixtures ,, and for the recovery of valuable material ^' sulfur ^' .

Exhaust air mixtures that can be cleaned by the method and the system environmentally friendly, are, for example.

Biogenic fuel gases: biogas - hydrolysis gas - landfill gas - sewage gas - digester gas - pyrolysis gas - wood gas - Kompogas;

Geogenic (deep) gases: mine gas - mine gas - geothermal energy or gases

deep drilling

Energetic gases: synthesis gas - associated gases - natural gas - sour gas - lean gas - refinery waste gases

Production (off) gases of the branches Chemicals / Food chemistry and Pharmacy - Oil mill

Sewer and sewage treatment plant waste gases

The process can free gas streams of H ₂ S, which have no or only 1% by volume of oxygen and are / are saturated with water vapor - can also be used for highly hydrocarbon-containing gas streams - such as sour gas or associated gas - for environmentally friendly desulfurization. If necessary, ammonia and, for example, carboxylic acids formed during hydrolysis and fermentation processes can be absorbed or decomposed by the microorganisms and the buffer material.

Regeneration of the filter material and cleaning of the exhaust air stream can take place in separate stations. Oxygen is necessary for the regeneration of the filter material. If no oxygen is present in the exhaust air stream, the at least one (partially) laden exhaust air filter material may be purged and regenerated in a separate stage with an oxygen-containing gas, wherein elemental sulfur and Sulfuric acid is formed from the iron sulfide and the resulting iron oxide can serve again for sulfide in the purification process.

In the following, the invention will be described with reference to oil mills, this description being merely exemplary and also applicable to the exhaust gases of others, o.g. Origin is suitable.

Oil mills are used to produce oil from oilseed rape, sunflower, sesame, linseed, camelina, poppy, moringa, nutmeg, pomegranate seeds, peanuts, hazelnut, olives, almonds, walnuts, jatropha, jojoba, soy, black cumin, pumpkin seeds and many other oily seeds. To squeeze oil fruits. In larger commercial mills (so-called central, industrial oil mills), a solvent extraction of the press cake with a hydrocarbon is often carried out after the purely mechanical pressing at elevated temperatures in order to remove further vegetable oil as quantitatively as possible. The solvent is removed from the oil by a known method and also circulated - but there are still volatile components in the oil, which are then detected with the process exhaust air and fed to a waste air purification. In addition to the exposure to solvents, production of hydrogen sulfide in the exhaust air stream of the oil mill releases. The exhaust air is sucked off and fed to a cleaning.

Currently, in so-called desolventiser toaster cooler systems, sometimes called only "toaster", cooled from the oil press exhaust air, then a

Washing process and then fed to a biological post-purification (eg., A biofilter). ,

The principle procedure of oil extraction can be described as follows: The oil crops arrive at a treatment. In a first treatment stage flocculation takes place for the first digestion of the oil crops. These flakes are then heated, because this makes the oil thinner - and then get into pressing, where much of the oil content is squeezed out. The press oil arrives after a cleaning to a degumming plant. The warm press cake is fed into an extraction stage. There is the washing out of the remaining oil with a solvent, such as technical n-hexane. The remaining extra In the desolventiser toaster cooler system, residual grinding agent is then freed of residual solvent, brought to a storable consistency and conveyed in shredded silos.

The mixture of pressing and extraction oil enters the degumming plant, where the mixture of water, water-soluble ingredients and suspended particles is freed. After a final cooling, the finished degummed crude oil is stored in tanks.

The Desolventiser Toaster Cooler system is usually constructed in several, usually stacked stages. The material to be treated passes through the plant from top to bottom and is passed between the stages via corresponding rotary valves. In the first, upper stages, the shot / solvent mixture is treated with steam and additionally heated via an external heating, for example, steam-heated raised floors. In this way, solvent components are expelled from the solid (shot). In the other stages of the desolventiser toaster cooler system, drying (so-called toaster stage) and finally cooling of the cleaned scrap takes place.

For drying and cooling of the scrap meal of said oil crops fresh air is usually used (as a transport medium for the expelled moisture). The obtained during drying and cooling exhaust air mixture of the oil mill is usually contaminated with the following ingredients:

• partially toxic odors, such as hydrogen sulphide, from the amino acids of oilseeds or oilseeds

• residues of hydrocarbons used for extraction and the like

Extractants, such as n-hexane, methyl chloride, benzine residues, acetone, 2-methylpentane, methylcyclopentane, ethanol

• Water

The main components of the exhaust air are nitrogen, carbon dioxide and oxygen.

A particular problem is the resulting during pressing hydrogen sulfide or similar sulfhydrides and other sulfur-containing compounds, both are highly toxic and can lead to significant odor nuisance or health hazards.

Representative exhaust air investigations of oil mills have considerable burdens in particular by hydrogen sulfide with concentrations of 40 to 50,000 ppm corresponding to 460 to 575 g / m ³ exhaust air. Other essential components of the exhaust air are the solvent constituents acetone, hexane, 2-methylpentane, methylcyclopentane, ethanol with concentrations of 10 to 1000 mg / m ³ and in lower concentrations n-pentane and n-butane (<10 mg / m ³ ) Further components from the mineral oil of the mineral oil scrubber are technically unavoidable.

Of these substances, the hydrogen sulfide cargo is serious, but also the acetone-hexane and methylpentane residues in the exhaust air are sustainable to remove. ,

Currently, the hydrogen sulfide components in this oil mill plant by a soda lye scrubber and the organic components with a downstream bioactive filter - eg. Biofilter with bark mulch - cleaned from the exhaust air (DE 40 17 230 A1). The bark filters are driven damp and are colonized with microorganisms which can perform a conversion of various pollutants, such as hexane or and other odors in a temperature range of about 20 - 50 ° C. Toxic loads could not be purified in this way.

Among other things, the known filter was unsatisfactory in that bark mulch easily decomposed (earthed). The cleaning performance per kg of bark mulch filter material was also able to be improved.

The reduction of toxic loads of hydrogen sulfide has been attempted via upstream chemical scrubbers. These scrubbers are very expensive to operate, very maintenance-intensive and also lead in downstream wastewater treatment plants by the high sulfur load to significant malfunction.

In contrast, it is an object of the invention sulfide-containing and possibly hydrocarbon-containing exhaust air to rid of sulfides so environmentally friendly. In particular, exhaust gases are to be processed in an environmentally friendly manner so that no toxic and environmentally hazardous emissions or water-polluting substances escape and also the odor nuisance is minimized.

The invention solves the problem by a method according to claim 1, as well as the use of a special populated with microorganisms porous filter material. Advantageous developments emerge from the dependent claims.

The exhaust air is passed through a chemico-biological-reactive filter material using the process exhaust properties directly (moist, warm, highly polluted waste air mixture). This filter material is presented in reactor vessels in which it can be flowed through.

Preferably serve as a biocompatible, porous support material of the filter material substantially from Ca (OH) ₂ , lime, dolomite (MgCa (C0 ₃ ) ₂ ) and natural fibers produced moldings. The preferred fibrous materials are cellulose or other vegetable fibers, rock wool, wood fibers and the like. used. These fibers have the advantage that they have a moisture-balancing effect, are readily colonized by bacteria and can easily be recycled in agriculture or in road construction. Preferably, the carrier material comprises about 30% by weight of natural fibers, such as cellulose fibers, 55-66% by weight of porous stabilizing additive - preferred

Calcium carbonate and magnesium calcium carbonate. Such a material has due to the high Erdalkalicarbonatanteils excellent buffering and pressure stability, it is described as UGNclean pellets in the trade and in WO 2012/152269 A2.

This support material is mixed with iron oxide or other iron compounds readily reactive with hydrogen sulfide. The material may include better additives, such as zinc compounds, fertilizer salts and possibly activated carbon as adsorbent for better energy supply to the bacteria and for adsorption or Abreaction of pollutants. Possibly. Other additives, such as zeolites, clays, etc. can also be used. In this case, initially the porous pressure-resistant carrier material essentially consists of fibers and inorganic constituents (such as produced by adding Ca (OH) 2, cement) as a binder and moistened and then populated with suitable microorganisms.

An essential feature of the pellets described is that the sulfide load in the exhaust air reacts with the additives contained and is oxidized with oxygen to elemental sulfur. The previously gaseous sulphide load is thus altered by chemical-biological processes, i. into a solid (= elemental sulfur or solid sulfur compounds), which builds up on the pellets. The described active filter material with inorganic iron compounds can in combination in the material settled bacteria clean the exhaust air stream. In the present invention, toxic hydrogen sulfide is chemically bound as black iron sulfide. Hydrogen sulfide conversion involves, in one embodiment, admixed iron oxide hydrate to the filter material which forms iron sulfide in an exothermic reaction with hydrogen sulfide water.

It is believed that the iron oxide hydrate also forms elemental sulfur with hydrogen sulfide, oxygen and water, this process being assisted by the presence of sulfoclastic bacteria. Furthermore, the carrier material may also have microorganisms which are able to degrade hydrocarbons, so that in addition to the desulfurization a significant degradation of various hydrocarbons by the microorganisms on the biocompatible carrier material occurs.

The black iron sulfide formed from an iron compound such as iron oxide hydrate and hydrogen sulfide is converted to iron oxide and sulfur by atmospheric oxygen. The filter thus regenerates itself.

Among others, the following reactions take place in the active filter material:

Reaction of iron compounds to iron sulfide:

desulphurization:

Fe ²⁺ (OH) _x + Fe ³⁺ + H ₂ O + hydrogen sulfide FeS _x + S + H ₂ 0

Regeneration:

FeS _x + 0 ₂ + H ₂ 0 ^■ »S + Fe (OH) _x In addition, further reactions take place, including: hydrogen sulfide + 0 ₂ S + H20

Hydrogen sulfide + 02 sulfuric acid

The iron sulfide formed as the first reaction product is constantly regenerated in the filter by the present sulfoclastic bacteria to iron oxide and thus achieves a high cleaning capacity of the filter material:

Biological regeneration of the filter material

2 Fe (II) S +0 ₂ + H ₂ 0 2 Fe (III) (OH) x + 2S

The inventive method for the purification of exhaust air mixtures with sulfur compounds - for example, from processing processes of oil mills for oilseeds - has at least the following steps:

- Passing the exhaust air mixture through at least one chemical-biological reactive filter with: porous framework particles with inorganically bound natural fibers and support material, at least one iron compound, sulfatoclastic organisms, additives;

- Removing the cleaned in at least one reactive filter exhaust air stream from the chemically-biologically active reactive filter.

The addition of water to the exhaust stream inside and / or outside of the at least one reaction vessel with the biological-chemical reactive filter, preferably to saturation, may be necessary, e.g. if the exhaust air does not provide sufficient moisture and also serves for cooling.

The supply of fresh air to the exhaust air flow can be made to the for the

Sulfide oxidation necessary to provide oxygen, but also, for example, to dilute the concentration of the same and so the temperature in the filter, where a exothermic reaction takes place, to control. The gas quantities of exhaust air and fresh air can be regulated and / or controlled according to measured system parameters.

But it is also possible to use several reactive filters, one of which is used for cleaning and another is regenerated with oxygen-containing gas.

Preferably, the purified exhaust air stream when it comes from a plant, returned to this - eg. In the Ölmühlet - and thus any discharge of exhaust air into the environment avoided (zero emission).

It often makes sense that several reaction vessels are arranged with biological-chemically reactive moldings in series and / or in parallel.

It may also be beneficial that the exhaust air is dedusted - thereby preventing mechanical clogging of the exhaust paths.

In order to increase the throughput of the system, the exhaust air can be sucked out of the reactive filter with negative pressure.

The heat of reaction occurring during the active filtration step (reaction of iron compounds to iron sulfide) can heat a cooling medium, which is optionally recycled to the plant - here an oil mill as a heat carrier, as well as the resulting during the cooling and drying steps waste heat can be fed to a recuperator , The clean gas temperature after flow is higher than the raw gas temperature before flow due to exothermic reactions in the filter. In a multi-stage process, this can lead to unwanted heating, so if necessary heat is dissipated between the individual stages. A second alternative to influence the heat balance is the addition of fresh air to avoid local over-temperatures in the package.

Exhaust air withdrawn from the circulating exhaust airflow air can be subjected to the regenerative purification process according to the invention. Preferably, the biological reactive filter material is used together with materials selected from nutrients, adsorbents, pH buffers and Fe (OH) x and mixtures thereof.

The shape, size, arrangement and number of or in series and or serially installed and filled with porous filter material moldings reactor vessel depends on the pollutant load, the flow rate and the degree of cleaning to be achieved.

The invention further relates to the use of a biological reactive filter material having a skeletal material populated with sulfatoclastic organisms containing fibers, a biocompatible inorganic binder content, iron compounds and materials selected from the group consisting of nutrients, adsorbents, pH buffers and catalytic Materials for the purification of sulphide and possibly hydrocarbons in the exhaust air.

Advantageously, the inventive method requires neither a pre-cleaning of the exhaust air before entering the reactive filter, nor a special waste disposal of the loaded filter material. At the same time an odor avoidance takes place by the conversion of odorous volatiles volatile organic sulfides by sulfides present in the filter material metabolizing bacteria, eg Acidithiobacillus. In the filter material and hydrocarbon degrading organisms can be settled if the exhaust gas is hydrocarbon-containing. Thus, not only the highly toxic hydrogen sulfide gas, but also the odor-intensive volatile organic sulfides and hydrogen sulfides and hydrocarbons are degraded environmentally friendly. The filtration process with the biological reactive filter material can be successfully carried out as soon as more than about 1 vol.% Oxygen in the exhaust stream and sufficient moisture is present - preferably in the range of moisture saturation.

Of crucial importance is also a correct temperature management of the raw gas stream and the filter interior because of the expiring exothermic

Iron sulfide reaction and the temperature sensitivity of the colonizing microorganisms. Therefore, optimum results are achieved when the reactive film is used in the temperature range between 25 and 60 ° C, preferably 30 to 50 ° C. The temperature management can be done by adding fresh air to the exhaust stream and water.

In its most general embodiment, the invention relates to a method for exhaust air purification from plant parts of oil mills with the following process steps:

• The warm, moist exhaust air laden with pollutants and odors is led to the at least one reactive filter.

• The raw exhaust air is conditioned (temperature, humidity, volumetric flow), if necessary also an oxygen content are set)

In the reactive filter, the hydrogen sulfide is trapped as iron sulfide (FIG. 3) during prolonged use, it is oxidized to elemental sulfur in the presence of oxygen and the pellets of the reactive filter form a sulfur film of elemental sulfur on their surface (see FIG.

• The loaded and used filter material is due to its in it

enriched constituents - essentially iron sulfide, sulfates, sulfur and water - harmless and may possibly be used without problems as a soil conditioner or for composting purposes.

• In one embodiment, at least two series-connected or series-connected reactive filters are installed to ensure continuous operation of exhaust air cleaning. When the retention capacity of the first filter is exhausted, the second filter is used as the input filter and vice versa.

• There is no wastewater because the exhaust air to be treated only has a water content of up to 100% relative saturation and the exhaust air processed in the process has a significantly higher relative humidity due to the exothermic process of sulfide oxidation with air heating. has and thus introduced at lower temperatures - for example .. injected - water freight with absorbs.

As a result, sulfide-cleaned exhaust air is drawn off from the purification stage, which can then be introduced into at least one further downstream biofilter, for example for the decomposition of organic residues or for fine cleaning.

Due to the reactive filter system, filled with the pellets as reactive mass (fixed bed reactor), the total pressure ratio of existing systems is hardly affected, so that no or little additional energy for the transport of the exhaust air must be expended. This is due to the low pressure losses of the reactive; formed from moldings filter mass and high residence times / low filter volume load. An inventive active filter according to the invention uses existing exhaust air humidity to 100% and operates between 25 - 60 ° C, preferably between 30 and 50 ° C. It is important that the material does not get so wet that the air flow to the bacteria is hindered. The necessary for the regeneration reactions oxygen content of the active filter is variable in larger areas. Up to <5 ppm H2S (~ 0 ppm in praxi) can be removed in the exhaust air stream in one filter stage. Suitable additions can also be used to convert NH ₃ and many other odors. Due to the chemical composition with a high, basic content by the basic skeleton material, the filter material has a high buffering capacity, can absorb sulfuric acid formed to sulfate and make it environmentally friendly.

The spent pellets - whether by pore formation, exhaustion of the buffer material or by dead bacteria, can be introduced as fertilizer or soil loosening agent in soil surfaces.

For a possible ultrafine cleaning, after the transfer of the toxic cargo in the untoxic area, residual loads of less than 20 ppm of hydrogen sulfide can occur after the first filter stage, which are removed with a series downstream filter unit (eg, the clean air flow through another reactive filter or A conventional Abluftflächen- or container filter (eg bark mulch filter) are guided., That the process quasi-dry completely without attack of Wastewater is discharged, resulting in significant savings on wastewater and a highly environmentally friendly behavior of the plant.

In most cases, the water required for the reactions can be recovered from the ongoing process or added in relatively small amounts.

According to the invention, the exhaust air flow of hydrogen sulfide freights of several 10,000 ppm can be cleaned with an efficiency of over 99.9%.

Further, elemental sulfur - a valuable material recovered, which can be separated from the moldings in a separate process.

The invention will be described below with reference to an embodiment - the cleaning of oil mill exhaust gases - closer. Showing:

Fig. 1 is a diagram of a system according to the invention for carrying out the method

Fig. 2 is a photograph of a loaded shaped body with sulfur layer and formed iron sulfide

Fig. 3 is a photograph of loaded moldings from the interior of a filter.

Fig. 1 shows a system for the purification of exhaust air from an oil mill, the schematic diagram of the main course of the exhaust gas streams is shown. The invention is by no means limited to such a construction, but generally relates to the reactive filtration of exhaust gases through filters with the above-described, adapted by additions to the use of scaffold material.

Reference numeral 10 denotes a desolventiser-to-toaster cooler system. Along an exhaust duct 1, the warm, moist, H ₂ S-containing exhaust air from the Aspirated system 10 and initially passed through a mechanical dust filter 16.

The thus dedusted raw exhaust air, which was optionally cooled and mixed with fresh air, then passes into a first reactive biofilter 32 according to the invention. The active biofilter 32 and its function will be described in more detail below.

The exhaust duct 14 continues into a second reactive biofilter 42, in which the framework material according to the invention with additives is also located. There are short-circuit lines 14 ', 14 ", the diversion of the exhaust stream 14 of the

Desolventiser toaster system to each other reactive biofilter 32, 42nd

enable. As a result, the first filter can be refilled when the skeleton material is exhausted, while the exhaust gas purification in the connected filter continues uninterrupted. Possibly. Further filter units may be provided downstream of the second filter 42.

The purified exhaust air exiting the filter located at the most downstream is returned to the desolventiser system of the oil mill.

An active filter according to the invention preferably uses existing exhaust air humidity to 100% and operates between 30 - 70 ^e C. Ggf. Water can be added to achieve optimum humidity. It is important that the material does not get so wet that the air flow to the bacteria is hindered. The oxygen content of the active filter required for the reactions can be variable in larger ranges and <5 ppm H2S (~ 0 ppm in practice) can be removed in the exhaust air stream. Suitable additions can also be used to convert NH3 and many odors. Due to the chemical composition with a high basic content (eg CaCO 3, MgCO 3, etc.), the filter material has a high buffering capacity and can scavenge formed sulfuric acid to sulfate and make it environmentally compatible.

The added amount of fresh air is controlled so that it provides the necessary oxygen to set a constant, circulating circulation flow of the exhaust air and the microorganisms in the filters are not overloaded.

Fig. 2 shows a photograph of a loaded shaped body with sulfur layer and formed black iron sulfide - this comes from the edge region of a filter and had much contact with oxygen. As a result, the hydrogen sulfide was oxidized via iron sulfide (black dots) to elemental sulfur.

In Figure 3 - a photograph of a loaded shaped article with already formed black iron sulfide in the edge region - but still without oxidation of the iron sulfide to sulfur - it can be seen that the sulfatoclastic bacteria in the moldings were not yet in contact with sufficient oxygen to the black iron sulfide to further oxidize sulfur and iron oxide (hydrate). It clearly shows how effectively the colonized microorganisms convert the toxic hydrogen sulphide into elemental sulfur and its compounds. However, this is possible only because of the iron oxide hydrate added to the framework material - the state of the art in which microorganisms on bark are intended to decompose the hydrogen sulfide can not carry out this reaction to elemental sulfur in the absence of iron oxide present. Consequently, the framework used according to the invention has a higher absorption capacity and cleanability than the

Bark mulch filter of the prior art.

A "new" pellet - you can clearly see the fibers that connect the bright framework material - in contact with the hydrogen sulfide-containing gas, especially the iron compounds react on the surface and then form the first

Layer structure of Fig. 3, which is then further oxidized on the surface to sulfur (see Fig. 2).

An active filter according to the invention preferably uses the existing relative exhaust air humidity of up to 100% and operates between 30-70 ° C, preferably between 30-50 ° C and particularly preferably between 40 and 50 ° C. It is important that the material is not over-moistened to prevent clogging of the pore system of the framework. The air oxygen content of the active filter / exhaust air required for the reactions must be precisely metered or carried in sufficient concentrations in the exhaust air. In addition, process water needs to be equivalent Be injected quantities. Due to the chemical composition of the framework with a high basic content, the filter material has a high buffer capacity and can absorb sulfuric acid formed into sulfate and discard environmentally friendly.

Although the invention has been described in detail with reference to a Ölmühlenäbgasreinigung, it is obvious to those skilled in the art that they - adapted according to the expert knowledge - can also be used to clean other gases with sulfide content. For example, exhaust fumes from refineries, digesters, composting plants, the food industry and pharmaceuticals can be effectively freed of toxic gaseous sulphides in an environmentally friendly manner. The scope of the application should therefore not be limited to the embodiment, but only by the appended claims.

LIST OF REFERENCE NUMBERS

10 Desolventiser Toaster Chiller Plant

14, 14 ', 14 "exhaust duct

16 dust filters

32 active biofilters

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Claims

claims

1. A process for the purification of sulfide and optionally hydrocarbon-containing

Exhaust air mixtures, with the steps

- Passing the exhaust air mixture through at least one chemical-biological reactive filter with: porous framework particles with inorganically bound natural fibers and pH-buffering support material, at least one iron compound, sulfatoclastic and possibly hydrocarbon-degrading organisms, additives; and

2. The method according to claim 1, characterized by adding water to the exhaust air flow within and / or outside of the at least one reaction vessel with the biological-chemical reactive filter to saturation.

3. The method according to claim 1, characterized by supplying oxygen or an oxygen-containing gas mixture, such as fresh air, to at least one reactive filter during or after the exhaust air mixture, so that the oxygen content of the oxygen-containing gas mixture is at least 1 vol.%

4. The method according to any one of the preceding claims, characterized in that the purified exhaust air mixture stream is returned to the gas-producing plant.

5. The method according to claim 1, characterized in that a plurality of reaction vessels are operated with biochemically reactive moldings in series and / or in parallel ..

6. The method according to claim 1 to 5, characterized in that the exhaust air is dedusted.

7. The method according to any one of claims 1 to 4, characterized in that the delivery of the exhaust air through the reactive filter with negative pressure and / or pressure takes place

8. The method according to any one of claims 1 to 5, wherein the heat of reaction incurred during the active filtration step heat a cooling medium, which is recycled to the gas-producing plant as a heat transfer medium.

9. The method according to any one of claims 1 to 6, wherein the temperature incurred during the cooling and drying step heated condensate.

10. The method according to any one of claims 1 to 7, wherein the exhaust air withdrawn from the circulating exhaust air stream is subjected to a regenerative cleaning process, which oxidizes the hydrogen sulfide to sulfur via iron sulfide and iron oxide.

11. The method according to any one of claims 1 to 8, characterized in that the biological reactive filter together with the regenerative reaction-promoting materials selected from nutrients, adsorbents, pH buffers and mixtures thereof is used.

12. The method according to any one of claims 1 to 9, wherein the gas quantities of exhaust air and fresh air are regulated and / or controlled according to measured system parameters.

13. Use of a biological reactive filter material with a scaffold material populated with sulfoclastic and optionally hydrocarbon degrading organisms and containing natural fibers, a content of biocompatible inorganic binder, iron compounds and materials selected from the group consisting of Nutrients, adsorbents, pH buffers and mixtures thereof for the purification of sulfide- and / or hydrocarbon-containing exhaust air, such as biogas, hydrolysis gas, landfill gas, sewage treatment plant biogas, pyrolysis gas wood gas, gases from composting, mine gas, mine gas, gases from geothermal and deep drilling; Synthesis gas, associated gas, natural gas, sour gas, lean gas; Production exhaust gases from the pharmaceutical and food industries, such as the exhaust air from oil mills.

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