WO2008040038A1

WO2008040038A1 - Process for separating off silicon-containing compounds from biogas

Info

Publication number: WO2008040038A1
Application number: PCT/AT2007/000459
Authority: WO
Inventors: Marianne Haberbauer; Johann Heinrich Bergmair; Francesca Accettola
Original assignee: Profactor Produktionsforschungs Gmbh
Priority date: 2006-10-03
Filing date: 2007-10-01
Publication date: 2008-04-10
Also published as: AT504325A4; AT504325B1; AT504325B8

Abstract

The invention describes a process for separating off at least in part at least one component from a gas mixture, in particular from biogas (2), wherein, in a reactor (4) having an interior (21), microorganisms (10) are provided for by a process liquid (9), in particular a wash solution and/or nutrient solution. In particular, silicon-containing compounds, such as siloxanes, are at least in part separated off via aerobic, in particular mesophilic, microorganisms (10).

Description

METHOD FOR SEPARATING SILIC-SITIVE COMPOUNDS FROM BIOGAS

The present invention relates to a method for the at least partial separation of at least one component from a gas mixture, in particular from biogas, wherein in a reactor microorganisms are supplied by a process liquid, in particular a washing and / or nutrient solution, and at least a device for at least partial separation a component from a gas mixture, in particular from biogas, comprising a reactor with microorganisms and at least one supply and discharge device for transporting the gas mixture and at least one process liquid, in particular a washing and / or nutrient solution, and their uses.

Biogases arise from the fermentation of agricultural residues, waste fermentation and industrial wastewater treatment or their combination. In addition to the main components of methane (CH ₄ ) and carbon dioxide (CO ₂ ) biogas also contains hydrogen sulphide, ammonia, halogenated and non-halogenated hydrocarbon compounds and various silicon compounds of different chain lengths, in particular higher and low molecular weight siloxanes. Biogases are also saturated with water vapor.

Although siloxanes are non-toxic, their presence in many biogases is undesirable. For a long time, biogas has been burned in gas engines, in particular in combined heat and power plants. However, this use of biogas causes problems with the increasing proportion of siloxanes in biogas in recent years. Investigations confirm that the siloxanes contained in biogases can lead to damage to internal combustion engines since, during the combustion of biogases in the combustion chamber, silicon oxide deposits on the metal parts of the combustion aggregates can be formed, which are very hard. These can act as dusts in the cylinder chamber and in the lubricating oil like an abrasive and accumulate in the combustion chamber as a glassy layers, which occasionally peel off and cause irreparable damage in the engine. But even in fuel cells, the siloxanes contained in biogases can damage the catalysts.

The purification of biogases for the removal of silicon compounds, in particular siloxanes, therefore plays an essential role in the utilization of biogases. At present, there is no standard method for removing the siloxanes from biogases.

The previously used methods for biogas purification are adsorption (often in conjunction with cooling as a precursor) and absorption with solvents. Adsorption can be used to remove siloxanes from the biogas. In practice, it has been found that the amount of activated carbon or other adsorbent required for separating or adsorbing impurities from the biogas is often considerable. Accordingly, the provision of the activated carbon, the replacement of the activated carbon and the disposal of the loaded activated carbon involve relatively high costs. By cooling, for example, to 4 ° C, the siloxanes are already reduced. Pollutants that occupy free adsorption sites of the activated carbon are discharged proportionally. The main advantage of the process lies in the improved absorption capacity of the activated carbon, since the consumption of activated carbon is generally lower with cooled gas. Adsorptive methods are e.g. from DE 10 2004 005 626 Al and from US 2006/0000352 A1.

In DE 102004 005 626 A1, only a partial flow from the digester gas is passed over the activated carbon and the remaining part left unpurified and then the two partial flows are brought together again, thereby a smaller amount of adsorbent (activated carbon) is required. This partial flow control reduces the degree of contamination in the total flow.

Patent US 2006/0000352 A1 uses various layers of filter media to remove siloxanes. The layers are arranged so that the higher molecular weight in the first layers are preferably removed. The pore size is in a relatively narrow range. Both inorganic (e.g., modified silica gel or zeolites) and carbon-based adsorption media are in a narrow range of pore size. The removal takes place via adsorption and also as molecular sieve.

A combination of adsorption and biodegradation is known from Offenlegungsschrift DE 3345944 A1. The gas stream containing one or more organic pollutants is passed through one or more biologically active beds which are produced by using a porous, pollutant-adsorbent high internal surface support selected from the group consisting of activated carbon, zeolite and silica gel a substrate-limited suspension of a bacterial mono- and / or mixed culture in contact is brought, and a liquid flow during operation in cocurrent or countercurrent circulates. This method is mainly used to remove odors. First, adsorption on the appropriate adsorbent followed by biodegradation.

Absorption is expensive due to the use of materials. Due to the high liquid requirement, the loaded medium is often regenerated in a desorption column and recirculated. By this solvent recovery, the absorption is associated with a considerable expenditure on equipment, but still the partial supply of fresh solution and at the same time the disposal of spent solution are necessary.

Very little is known about biological siloxane degradation (A. Dorosz et al., Pp. 545-552). There are two reasons why very little research work has been carried out on the degradation, and in particular the biodegradation, of siloxanes in the past. For a start, it was assumed that siloxanes are not biodegradable in the environment and thus inert. Only between 1960 and 1970 was it possible to prove that siloxanes are degradable and can thus cause damage. It is believed that biodegradation of silicon-organic polymers occurs by shortening the polymer chain and forming silanol groups at the site where the polymer chain was cut. Tests on the degradation of polydimethylsiloxanes (PDMS) showed that PDMS can not be degraded either in waste water (Lehmann 1996) or during composting (Smith 1998). Biodegradation of low and high molecular weight siloxanes has been observed among the bacterial species Pseudomonas, Proteus, Escherichia, Bacillus and Klebsiella and the fungi of the family Corticiaceae. Rosciszewski (1998) found that almost all polysiloxanes are biodegradable and that the degree of degradation depends on the structure of the siloxanes and the bacterial strain used.

Under normal conditions, octamethylcyclotetrasiloxane (D4) and its higher molecular weight counterpart decamethylcyclopentasiloxane (D5) are degraded in the soil to dimethylsilanediol (DMSD). In almost all leachate from manufacturers of silicon-containing materials DSMD could be found in an amount of mg / 1.

Grümping (1999) observed that octamethylcyclotetrasiloxane (D4) in the composting sludge can be decomposed under anaerobic conditions; Again, the main product of the mining was DSMD.

Biological processes are known from the published patent applications DE 199 20 258 A1, US 2004/0137610 A1 or US Pat. No. 5,413,714 A.

The invention DE 199 20 258 A1 relates to an anaerobic wet cleaning process. Biogas flows into a packed column and in countercurrent landfill leachate is applied. Within the packed column is then carried out a combined biological, chemical and physical cleaning. In this case, microorganisms are also immobilized on the packing in a packed column. The use of landfill leachate is to ensure that the hydrogen sulfide dissolved in the landfill water by the mass transfer in the reactor is precipitated in the form of sparingly soluble metal salts by heavy metal ions contained in the landfill leachate. At the same time, decomposition of halogenated hydrocarbons and silicon-containing ones can take place via the anaerobic microorganisms

Compounds which are also enriched in the landfill leachate from the landfill gas during the mass transfer occur. In order to provide the anaerobic microorganisms optimal living conditions and to achieve effective degradation performance, the column can be operated in a temperature range between 20 ⁰ C and 70 ⁰ C. It is used as an auxiliary landfill leachate and a separator for the heavy metal compounds is needed.

In US 2004/0137610 A1, a biofilter is preceded by a loading unit. This loading unit is designed to select a solvent in which to dissolve the VOCs to be purified (e.g., benzene, toluene, ethylbenzene, xylene, styrene, etc.) or, if there are no VOCs in the gas stream, these VOCs to gas phase. This ensures that there is always a constant concentration of VOCs on the biofilter in the gas phase.

The US 5,413,714 A also describes a process for the purification of gas mixtures, in particular for the separation of phenols. What is new is the use of a degradative packing that does not biodegrade during a life cycle of the substrate. The object of the present invention is therefore to provide a method and a device for the selective separation of at least one component, in particular silicon-containing compounds, from a gas mixture, such as biogas.

The task is independently solved by a method, wherein at least one

Component, in particular silicon-containing compounds, such as siloxanes, is at least partially separated via aerobic, in particular mesophilic, microorganisms and by a device, wherein at least partially separating at least one component, in particular silicon-containing compounds, such as siloxanes, aerobic, especially mesophilic, microorganisms arranged are. The advantage here is that an aerobic process for separating the at least one component from the gas mixture can be used by the use of aerobic microorganisms and thus, for example, the formation of odor-causing substances can be avoided. Furthermore, by using an aerobic method, the time for separating silicon-containing compounds from the gas mixture can be significantly reduced compared to anaerobic processes.

In a further development, it is provided that a gaseous oxidizing agent, in particular oxygen and / or concentrated atmospheric oxygen, is supplied to the biogas and a biogas oxidizing agent mixture is formed, whereby, for example, the biogas is not diluted by nitrogen and thus the purified biogas easily into the natural gas network can be fed.

In a further development, it is provided that the process liquid is mixed in the reactor with the inflowing biogas oxidizer mixture and optionally transported in a collection, whereby before coming into contact of the microorganisms with the biogas to be separated mixing of the process liquid of the biogas and the Oxidatonsmittels can take place and thus the efficiency of the process can be increased, in particular by increasing the metabolization process of the microorganisms.

The amount of oxidant needed can be determined stoichiometrically, which can provide optimal conditions for separation for the microorganisms in terms of oxygen content. Furthermore, it is provided that the oxidant supply is regulated as a function of the oxidizing agent content of the process liquid or of the biogas, preferably in a supply and / or discharge device sump and / or in the reactor, so that savings potentials with respect to the oxidant consumption, in particular if not air-acid. Substance, but as pure oxygen or other oxidants are used, can be exploited and thus the operating costs can be reduced.

It is also advantageous that in the collecting container, at least one distributing device, such as e.g. a stirrer, is arranged, which mixes the process liquid, the biogas or oxidant or a mixture thereof, thereby ensuring that the process liquid, the biogas and the oxidant in the sump constantly in motion and thus can not settle components, but the entire composition of each of the above components or the mixture thereof is available for the circulation.

Furthermore, it proves to be advantageous that the process liquid, the biogas, the oxidizing agent and / or the mixture thereof is heated to a temperature selected from a range between 20 ° C and 45 ° C, preferably 28 ° C, preferably in the collecting container, thereby the efficiency of the degradation of the microorganisms is optimized and the optimal living conditions are created. So that the aerobic microorganisms have optimal living conditions and can achieve the highest degradation rates, it is advantageous to operate the reactor in a temperature range between 20 ° to 45 ° C, in particular 28 ° C.

It is further provided that new process fluid, preferably via the collecting container, enters the circuit through a storage container and process fluid consumed by a waste container is removed, which ensures that all components in the process fluid are present in a predefined concentration over a defined period of time. For example, with the removal of process fluid, metabolic products of the microorganisms, dissolved salts, etc., can be removed from the circulating process fluid and, for example, an increase in the salt concentration can be avoided. It also proves advantageous that the supply of new process fluid can be regulated via a level control from the storage vessel. The process liquid can be transported via a conveying device, in particular a pump, from bottom to top, in particular from the collecting container into the upper region of the reactor and optionally uniformly sprayed in the reactor via a distributor device, in particular shower head, whereby a uniform application of the gas mixture over the entire interior of the reactor and thus over the entire microorganism population is made possible.

It also proves advantageous that the process liquid, the biogas, the oxidizing agent and / or the mixture thereof is uniformly distributed over the entire interior of the reactor by the arrangement of distributor plates, whereby it can be avoided that only in the edge regions of the reactor Separation or separation of silicon-containing compounds from the biogas takes place, since there is a greater or lesser inclination of the process liquid and / or of the biogas / oxidant / mixture for edge flow especially in straight areas.

The aerobic microorganisms may be supported on a support, in particular fillers, such as plastic fillers, e.g. Polyurethane foam, Raschig rings, etc. be immobilized, whereupon multiply the aerobic microorganisms. Furthermore, it proves to be advantageous that the active biomass does not have to be circulated in the device and ancillary equipment, but can remain stationary on the packing and thus a compact design without costly ancillary facilities is possible. This considerably simplifies the operation of the system and facilitates the maintenance and monitoring. The fact that a packed bed with a very large surface area is available as a biological lawn and that the liquid surface is in direct contact with the biological lawn in each case has a particularly favorable effect, so that the silicon-containing compounds are added very rapidly and completely the microorganisms can be transported. The activity of the bacteria can be maintained even if there is no biogas to be purified during downtime. It is sufficient in this case to maintain the circulation of the process liquid.

In a further development it is provided that as microorganisms mixed or pure cultures of Pseudomonas sp., Pseudomonas aeruginosa, Proteus mirabilis, Klebsiella pneumoniae, Escherichia coli, Klebsiella subtilis, Proteobacterium sp., Myroides sp., Chryseobacterium sp., Aquicella siphonis, Pigmentiphaga kullae, etc. and / or from sewage treatment plants siloxanproduzie- render industry-isolated bacterial strains and / or strains and / or in combination with other bacterial strains and species can be used, whereby a wide variety of microorganisms to be used, which are capable of aerobic conditions silicon-containing compounds and optionally other components of biogas to be separated.

In a further development, it is provided that, especially at the beginning of the process, the process liquid is inoculated with the microorganisms present, as a result of which the growth time of the microorganisms on the packings can be substantially shortened.

According to a preferred embodiment of the invention it is provided that the process is operated in countercurrent, in particular that the biogas flow from the bottom to the top and the nutrient medium from top to bottom, i. that the gas to be purified within the reactor is substantially opposite to the flow direction of the process liquid. This embodiment has the advantage that the gaseous medium and the liquid slide along the entire height of the reactor along each other, resulting in a long contact distance.

In an alternative embodiment it is provided that the process is operated in cocurrent, in particular that the biogas and the nutrient medium are circulated in the same direction. This embodiment has proved to be advantageous, above all, for devices whose interior of the reactor has a comparatively high level, since mixing of the gaseous medium and the process fluid can already take place prior to entry into the interior of the reactor.

In a further development, it is provided that a plurality of supply and discharge devices for the biogas, the oxidizing agent, the process liquid and / or mixture thereof are preferably arranged on the same level, and / or distributed at regular intervals over the entire diameter of the interior of the reactor, thereby it is ensured that there is a uniform distribution of the biogas, oxidizing agent, the process liquid and / or mixtures thereof over the entire reactor.

By arranging a device for enriching the biogas with oxidizing agent, such as air or oxygen, outside the reactor, a higher concentration of the oxidizing agent in the biogas and subsequently optionally in the process liquid can be achieved, so that a sufficient, for example at least stoichiometric amount of oxidizing agent in relation to the component to be separated for the metabolic activity the organisms is available. For example, a predeterminable amount of

Oxidant be introduced into the biogas and / or the process liquid, so that in the interior of the reactor, a buffer capacity for the case of malfunctions is available and thus the reactor can be continuously operated at least over a period of time.

The final concentration of oxygen in the purified biogas is a maximum value selected from a range with an upper limit of 2%, preferably 1.5%, in particular 1%, and a lower limit of 0.1%, preferably 0.3%, in particular 0 , 5%, which makes it possible for the purified biogas to be fed directly into the natural gas grid, thus fulfilling the ÖVGW guideline (maximum oxygen 0.5%).

Furthermore, it is provided that in the circuit at least one measuring device, in particular for measuring the oxidizing agent, the salt concentration, pH, etc., is arranged, whereby the efficiency of the device, in particular with respect to the operating costs, increases.

The process liquid, in particular the nutrient medium, may contain a plant fertilizer, preferably liquid plant fertilizer, whereby the nutrients necessary and optimized for bacterial growth are made available to the microorganisms.

Of advantage proves to be the selection of a plant fertilizer according to commercial plant fertilizer, because this cost-effective without manufacturing effort and yet optimized nutrient supply for the microorganisms can be offered. Particularly advantageous is a nutrient medium containing nitrogen, phosphorus, potassium, in particular in the ratio 3: 1: 3, and trace nutrients, such as 0.01% manganese, 0.002 to 0.005% zinc and / or copper and optionally traces of boron and / or or iron.

The plant fertilizer is diluted 1:50 to 1: 200, preferably 1: 100 of the original used in the process liquid, resulting in neither an oversupply nor an undersupply of nutrients of the microorganisms.

The pH of the process liquid is selected from a range with a lower limit of 5, in particular 5.5, preferably 6, and an upper limit of 7.5, in particular 7, preferably 6.5, whereby no addition of neither a liquor nor _β an acid is necessary because the process liquid, optionally with the degradation products of the silicon-containing compounds, serves as a buffer.

In a further development of the invention, the process liquid may comprise a solvent whose polarity is between that of water and siloxanes, whereby the water solubility of siloxanes can be increased.

However, this can also be achieved by using as solvent at least one surfactant in an amount selected from a range with a lower limit of 0.1%, preferably 0.3%, in particular 0.5% and an upper limit of 5%, preferably 3%, in particular 1% is contained in the process liquid.

In a further development of the invention, distributor plates can be arranged in the interior of the reactor, whereby a better distribution between the gas and the liquid phase is achieved.

The distributor plates are preferably designed in the form of a perforated plate in order to achieve the above-mentioned positive result.

In order to optimize the effect of the distributor plates, they may be arranged at regular intervals along the longitudinal extent of the reactor.

Furthermore, a collecting container for the supply and / or removal of process liquid, biogas, oxidizing agents, metabolic products of microorganisms, etc. may be arranged, in which optionally a distribution device, such as stirrer, is arranged, whereby the liquid is constantly in motion and for a continuous Mixing is taken care of. If the biogas or the biogas oxidant mixture also on the collecting container transported, so there is a continuous mixing of both the process liquid and the biogas and the oxidizing agent.

In one development of the invention, a heating device, in particular a heating jacket, can be arranged in and / or on the collecting container, whereby the effectiveness of the device can be improved by optimizing the reaction operations, in particular the living conditions for the microorganisms.

Furthermore, a droplet separator can be arranged downstream of the reactor in the course of the process liquid, the biogas, the oxidizing agent and / or the mixture thereof, as a result of which the quality of the gas mixture leaving the device can be improved and at the same time a recovery of process liquid is possible.

An advantage of the present invention is that an efficiency of 80% to 90% can be achieved, whereby a significantly improved, as known from the prior art separation of silicon-containing compounds from biogas can be created.

The invention further includes the use of the device according to the illustrated embodiments for pre-cleaning and / or cleaning, in particular removal of silicon-containing compounds from biogas or in the generation of electricity from biogas in combined heat and power systems, in particular fuel cells.

For a better understanding of the invention, this will be explained in more detail with reference to the accompanying drawings.

Show it:

Fig. 1 shows the system diagram of an embodiment of the device according to the invention;

Fig. 2 in plan view an embodiment of a distributor base.

By way of introduction, it should be noted that in the differently described embodiments identical parts are provided with the same reference numerals or the same component designations. in which the disclosures contained in the entire description can be applied mutatis mutandis to the same parts with the same reference numerals or the same component designations. Also, the position information selected in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and are to be transferred to a new position analogous to the new situation. Furthermore, individual features or combinations of features from the different exemplary embodiments shown and described can also represent independent, inventive or inventive solutions.

Biogas 2 is formed from organic matter, e.g. From plant waste or other biowaste in a multi-stage anaerobic process by a variety of bacteria. It is a gas mixture containing, inter alia, methane, carbon dioxide, ammonia, hydrogen sulfide, compounds containing silicon, etc. According to the invention, silicon-containing compounds can subsequently be removed from this gas mixture in an aerobic process by biological oxidation and with the aid of microorganisms 10.

1 describes a device 1 for at least partially removing at least one component from a gas mixture, in particular biogas 2. The biogas 2 is transported to the reactor 4 via a feed device 3. At the lower end of the reactor 4 is the reactor sump 5. The reactor 4 is preferably designed as a trickle bed reactor.

In the embodiment according to the invention, the oxidizing agent 6 is already added to the biogas 2 in the supply device 3. The oxidizer 6 is needed by the aerobic microorganisms 10 for the oxidation. In the device 1 according to the invention according to FIG. 1, this is enriched in the biogas 2 in the form of oxygen or atmospheric oxygen 6. According to the invention, a gaseous oxidizing agent 6 is used, although it should be mentioned that it is also possible to process liquid oxidizing agent 6 with the device 1 according to the invention. The biogas 2 and the oxidizing agent 6 enter the reactor sump 5 from the supply device 3 and rise in the interior 21 of the reactor 4. In the device 1 according to the invention, a plurality of feed and discharge devices 3, 7 are preferably arranged for the gas mixture in order to achieve a better distribution between gas and liquid phase zxi. By means of the targeted supply of the oxidizing agent 6 to the biogas 2, the exact concentration of the oxidizing agent content in the biogas can be determined. If a further dilution takes place in the collecting container 8 through the supply of process liquid 9, then it can again be precisely calculated in which concentration the oxidizing agent 6 has to be fed in order finally to find optimal conditions for the multiplication of the microorganisms 10 or the separation in the interior 21 of the reactor 4 silicon-containing compounds by the microorganisms 10 to achieve.

In addition to the function as washing liquid for leaching the reaction products from the reactor 4, in particular the filling body 22, the process liquid 9 can also take over the function of nutrient supply for the microorganisms 10. The nutrients may e.g. Trace elements, such as phosphorus, where the exact composition of nutrients depends on the particular bacterial culture. The addition of nutrients can also be done via the reservoir 8 for fresh process fluid 9.

The process fluid 9 can therefore be both a nutrient and a washing solution. It is preferably recycled. Preferably, the process liquid 9 comprises a liquid plant fertilizer and is used a predefined dilution.

In order to enable living conditions corresponding to the microorganisms 10, a pH value measurement and / or control can furthermore be provided continuously in the device 1.

The pH for the biological oxidation of silicon-containing compounds is preferably set in a range between pH 5 and pH 7.5, in particular between pH 5.5 and pH 6.5.

To further increase the efficiency of the device 1, the process liquid 9 can be preheated, for example to a temperature in the range between 20 ° and 45 ° C, preferably 28 ° C. It thus on the one hand accelerates the metabolic activity of the microorganisms 10 and on the other hand Thus, a higher concentration of oxidant 6 in the process liquid 9 can be achieved. For heating the process liquid 9, a heating device can be arranged in the process fluid circuit, for example as a heating jacket the collection 8. Alternatively or additionally, the reactor 4 itself can be at least partially heated. A temperature control is of course possible.

From the reactor sump 5 shows a discharge device 7 to a sump 8. About this discharge device 7, for example, spent process fluid 9 and metabolites of microorganisms 10 are transported to the sump 8. A distribution device 11, in particular a stirrer, can be arranged in the collecting container 8, in order to ensure thorough mixing of the process liquid 9. With the help of the distribution device 11, in particular stirrer, both a homogenization of the nutrients in the process liquid 9, as well as a mixing, for example, for regulating the pH value is possible.

To or from the collection container 8 may be arranged to further containers 3 or 3.7 supply. One of these containers may for example be a storage vessel 12, in which new, unused process liquid 9 is present. Consumed process liquid 9 can be transported into a further collecting vessel 13. The transport takes place via the supply or discharge devices 3, 7, in which at least one valve 14 and / or at least one delivery device, such as pump 15, can be located.

For heating the process liquid 9, the collecting container 8 can be heated. This can be achieved, for example, by a heating jacket 16, which is located around the collecting container 8.

The process liquid 9 can be transported from the collecting container 8 to the reactor 4 via a further supply device 3 and optionally interposed valves 14 and pumps 15. In addition to the process liquid 9, small quantities of biogas 2, oxidizing agent 6 or a mixture thereof may also be contained.

In an alternative embodiment, the process liquid 9 can be transported from a storage vessel 12 directly into the reactor 4 and from there via a conveyor 15, in particular pump, are directed to the upper end 17 of the reactor 4.

In order to achieve a uniform distribution of the process fluid 9 in the upper end 17 of the reactor 4, a distributor device 18, such as a shower head, can be arranged. In order to keep the distribution of the process liquid 9, the biogas 2, or oxidant 6 over the entire height of the reactor 4 approximately uniformly over the process process, at least one distributor plate 19 may be arranged at regular intervals. In order to improve the efficiency or the mixing, it is also possible for a plurality of distribution plates 19 to be arranged at regular intervals.

An embodiment of a distributor base 19 is shown in FIG. 2. Here, the distributor plate 19 is formed in the form of a perforated plate, wherein 19 openings 20, such as holes are arranged only in the center of the distributor plate.

In an alternative embodiment, not shown, the apertures 20 may also be used in other geometric figures, such as quadrangular, e.g. rectangular or square, polygonal, oval, etc. may be arranged. Of course, the openings 20 may also be arranged over the entire diameter of the distributor base 19.

In the interior 21 of the reactor 4 are the packing 22, on which microorganisms 10 are immobilized. As a result, the active biomass does not have to be run in the circulation and by ancillary facilities and is a compact design without costly ancillary facilities allows. By the operation of the device 1 according to the invention, the maintenance and monitoring can be facilitated. The material of the packing 22 does not normally need to be replaced, further reducing maintenance costs. The fillers 22 may be e.g. be formed in the form of Raschig rings and made of different materials, such as glass, plastic, etc. exist. Furthermore, the use of cullet is possible, but also other packing 22, such. Activated carbon, can be used. Of course, a mixture of different materials of the packing 22 is conceivable. In any case, the material of the filling bodies 22 should be such that aerobic microorganisms 10 can settle on them and be selected such that they are not degraded by the microorganisms 10. Usable as Füllk0per material are also various plastic foams, e.g. Polyurethane foam, which may be both open-celled and closed-celled.

The microorganisms 10, in particular bacterial species or strains Pseudomonas sp., Pseudomonas aeruginosa, Proteus mirabilis, Klebsiella pneumoniae, Escherichia coli, adhesives siella subtilis, Proteobacterium sp., Myroides sp., Chryseobacterium sp., Aquicella siphonis, Pigmentiphaga kullae, etc. and / or bacterial strains isolated from sewage treatment plants of siloxane-producing industries are active organisms capable of degrading siloxanes. A combination of the aforementioned bacterial species or strains in combination with other bacterial strains and species can also facilitate the degradation of siloxanes.

In the flow course of the gas mixture, in particular purified biogas 2, a droplet separator 23 can then be arranged next to the reactor 4, so that optionally contained in the gas mixture process liquid droplets can be deposited and thus a more dry, purified product is available for further use. The mist eliminator 23 can be connected to the interior 21 of the reactor 4 via a further removal device 7.

The supply of the oxidizing agent 6, in particular oxygen or atmospheric oxygen, makes it possible for microorganisms 10 to settle in the interior 21 of the reactor, which preferably can survive aerobically or optionally aerobically and multiply, and a separation of the silicon-containing compounds enable biogas 2. It can thereby be achieved that, for example, biogas 2, which is used further, contains approximately free or a drastically reduced proportion of silicon-containing compounds and thus damages which could be caused by them, for example, are avoided. The microorganisms 10 are able to oxidize silicon-containing compounds under oxygen consumption. The reaction mechanisms are well known, so that reference is made in this regard in this regard to various technical literature or these can also be seen from the documents mentioned in the introduction to the prior art.

Of course, it is possible to operate the reactor 4 both in cocurrent and countercurrent. If the reactor 4 is operated countercurrently, the biogas 2 and the oxidizing agent 6 or the mixture thereof into the reactor 4 and via a distributor 18, which is arranged at the upper end 17 of the reactor 4, passes through the process liquid 9 in the reactor 4th

It is also possible to operate the device 1 in cocurrent, wherein, for example, both the biogas 2, oxidizing agent 6 or the mixture thereof and the process Fluids sigkeit 9 are brought via the distributor 18 at the upper end 17 in the interior 21 of the reactor 4.

In one embodiment, not shown, it is of course also possible that the distributor 18 is not only located at the upper end 17 of the reactor 4, but that there are a plurality of distribution devices 18 distributed at regular intervals over the height of the reactor 4 and thereby a uniform distribution of the biogas 2, the oxidizing agent 6 or the mixture thereof and the process liquid 9 can be achieved.

Since the products formed in the reaction in the reactor 4 accumulate in the process liquid 9, it is advantageous, for example, to monitor the salt content of the process liquid 9 and to adjust it if necessary. The monitoring can be done either discontinuously, manually, but on the other hand it is also possible to make them continuously by means of appropriate measuring device in the process fluid circuit. Measuring devices for determining the salt content in a liquid are known from the prior art. In a further consequence, of course, it is also possible to remove other products, for example by precipitation from the process liquid 9.

The process liquid 9 may comprise a solvent whose polarity is between that of water and siloxanes, or a surfactant in an amount selected from a range with a lower limit of 0.1%, preferably 0.3%, in particular 0.5%. and an upper limit of 5%, preferably 3%, especially 1%, whereby the water-solubility of silicon-containing compounds can be increased.

The resulting in the interior 21 of the reactor 4 reaction products are washed out by means of the process liquid 9 from the interior 21 into the reactor sump 5, whereby a continuous operation of the reactor 4 is made possible here. As a result, the process liquid 9 with the reaction products contained therein is removed from the reactor sump 5 via a discharge device 7 from the reactor 4.

The thus purified gas mixture is withdrawn from the reactor 4, preferably above an optionally existing level of process liquid 9, via a discharge line 7. For a short period of stoppage, it is advantageous to maintain the activity of the microorganisms 10, even if no biogas 2 to be purified is obtained. Thus, a restart phase of the reactor 4 can be avoided.

In order to shorten the start-up phase of the device 1, in particular of the reactor 4, it is possible to inoculate the process liquid 9 with the respective microorganisms 10.

As a variant of the process liquid introduction, the material of the filling bodies 22 can, as not shown, be subdivided into several stages, which are provided with laterally inclined dividing bases, e.g. Bell bottoms are limited, which allow the lateral outflow of the process liquid 9 of the respective overlying stage in a separate channel. In each stage, the process liquid 9 is introduced via at least one distribution device 18, in particular shower. The number of stages results from the expected concentration of the component to be separated in the gas mixture. This variant of the process liquid introduction causes a sufficient supply of the microorganisms 10 with oxidizing agent 6.

As already mentioned, the device 1 can be used for the separation or partial separation of silicon-containing compounds from biogas 2, the purified biogas 2 on the one hand can be thermally utilized and on the other hand, it is also possible, this biogas 2 for power generation in power heat Coupling systems, in particular fuel cells use.

All statements on ranges of values in the description of the present invention should be understood to include any and all sub-ranges thereof, e.g. the indication 1 to 10 should be understood to include all sub-ranges, starting from the lower limit 1 and the upper limit 10, i. all subregions begin with a lower limit of 1 or greater and end at an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1 or 5.5 to 10.

The embodiments show possible embodiments of the device 1, wherein it should be noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but rather also various combinations of the individual embodiments are mutually possible and this variation possibility due to the doctrine of technical action by objective invention in the skill of those skilled in this technical field. Thus, all conceivable variants of embodiment, which are possible by combinations of individual details of the embodiment variant shown and described, are also included in the scope of protection.

For the sake of order, it should finally be pointed out that in order to better understand the structure of the device 1, these or their components have been shown partially unevenly and / or enlarged and / or reduced in size.

The problem underlying the independent inventive solutions can be taken from the description.

Set up reference signs

1 device

2 biogas

3 feeder

4 reactor

5 reactor sump

6 oxidizing agents

7 discharge device

8 collection containers

9 process liquid 10 microorganisms

11 distribution device

12 storage vessel

13 collection vessel 14 valve

15 conveyor

16 heating jacket

17 upper end 18 distribution device

19 distributor bottom

20 breakthrough

21 Interior 22 Fillings

23 tropical separators

Claims

Patent claims

1. A process for the at least partial separation of at least one component from a gas mixture, in particular biogas (2), wherein in a reactor (4) with an interior (21) microorganisms (10) by a process liquid (9), in particular a

Washing and / or nutrient solution to be supplied, characterized in that the at least one component, in particular silicon-containing compounds such as siloxanes, at least partially separated via aerobic, in particular mesophilic, microorganisms (10).

2. The method according to claim 1, characterized in that a gaseous Oxidati- onsmittel (6), in particular oxygen and / or air to the biogas (2) is supplied and a biogas oxidant mixture is formed.

3. The method according to any one of claims 1 or 2, characterized in that the process liquid (9) in the reactor (4) with the inflowing biogas (2), oxidizing agent (6) and / or the mixture thereof is mixed and optionally in a collecting container (8) is transported.

4. The method according to claim 2 or 3, characterized in that the amount of the required oxidizing agent (6) is determined stoichiometrically.

5. The method according to any one of claims 2 to 4, characterized in that the Oxid dationsmittelzufuhr depending on the oxidant content of the process liquid (9) and / or the biogas (2) in a supply or discharge device (3,7), in the collecting container (8) and / or in the reactor (4) is regulated.

6. The method according to any one of claims 1 to 5, characterized in that in the collecting container (8) by a distributor (11), in particular stirrer, the process liquid (9), the biogas (2) or oxidant (6) or the mixture be mixed from it.

7. The method according to any one of claims 1 to 6, characterized in that the process liquid (9), the biogas (2), the oxidizing agent (6) and / or the mixture thereof to a temperature selected from a range between 20 ° C and 45 ° C, preferably 28 ° C, preferably in the collecting container (8) is heated.

8. The method according to any one of claims 1 to 7, characterized in that by a storage vessel (12) new process fluid (9), preferably via the collecting container (8), in the circuit, optionally regulated by a level control passes, and through a collecting vessel (13) spent process fluid (9) is removed.

9. The method according to any one of claims 1 to 8, characterized in that the process liquid (9) via a conveyor (15), in particular pump, from bottom to top, in particular from the collecting container (8) in an upper region of the interior (21). of the reactor (4) is transported and optionally via at least one distribution device (18), in particular shower head, in the reactor (4) is uniformly sprayed.

10. The method according to any one of claims 1 to 9, characterized in that by the arrangement of at least one distributor plate (19), the process liquid (9), the biogas (2), the oxidizing agent (6) and / or the mixture thereof via the interior (21) of the reactor (4) are evenly distributed.

11. The method according to any one of claims 1 to 10, characterized in that the aerobic microorganisms (10) on a carrier, in particular packing (22), such as expanded clay,

Plastic filling bodies, such as e.g. Polyurethane foam, Raschig rings, etc. are immobilized.

12. The method according to any one of claims 1 to 11, characterized in that as microorganisms (10) mixed or pure cultures of Pseudomonas sp., Pseudomonas aeruginosa, Proteus mirabilis, Klebsiella pneumoniae, Escherichia coli, Klebsiella subtilis, Proteobacterium sp., Myroides sp , Chryseobacterium sp., Aquicella siphonis, Pigmentiphaga kullae, etc. and / or bacterial strains or strains isolated from sewage treatment plants of siloxane-producing industry and / or used in combination with other bacterial strains and species.

13. The method according to any one of claims 1 to 12, characterized in that in particular at the beginning of the process, the process liquid (9) optionally with the same as on the packing (22) located microorganisms (10) is inoculated.

14. The method according to any one of claims 1 to 13, characterized in that the method is operated in countercurrent, in particular that the biogas (2) from bottom to top and that the process liquid (9) flow from top to bottom.

15. The method according to any one of claims 1 to 13, characterized in that the method is operated in DC, in particular that the biogas (2) and the process liquid (9) are guided in the same direction in the circuit.

16. Device (1) for at least partially separating at least one component from a gas mixture, in particular from biogas (2), comprising a reactor (4) with microorganisms (10) and at least one supply and discharge device (3,7) for transport the gas mixture and at least one process liquid (9), in particular a washing and / or nutrient solution, characterized in that for at least partial separation of the at least one component, in particular silicon-containing compounds, such as siloxanes, aerobic, in particular mesophilic, microorganisms (10) are arranged ,

17. Device (1) according to claim 16, characterized in that a plurality of supply and discharge devices (3,7) for the biogas (2), the oxidizing agent (6), the process liquid (9) and / or mixture thereof, preferably the same plane and / or at regular intervals distributed over the entire diameter of the reactor (4) are arranged.

18. Device (1) according to claim 16 or 17, characterized in that a device for enriching the biogas with the oxidizing agent, such as air or oxygen, is arranged outside the reactor.

19. Device (I) according to one of claims 16 to 18, characterized in that the final concentration of oxygen of the purified biogas (2) has a maximum value selected from a range with an upper limit of 2%, preferably 1, 5%, in particular 1 % and a lower limit of 0.1%, preferably 0.3%, in particular 0.5%.

20. Device (1) according to any one of claims 16 to 19, characterized in that in the circuit at least one measuring device, in particular for measuring the Oxidationsmit- means (6), the salt concentration, pH, etc. is arranged.

21. Device (1) according to any one of claims 16 to 20, characterized in that the process liquid (9), in particular the nutrient medium, a plant fertilizer, preferably a liquid vegetable fertilizer includes.

22. Device (1) according to any one of claims 16 to 21, characterized in that the nutrient medium nitrogen, phosphorus, potassium, in particular in the ratio 3: 1: 3, and micronutrients, such as 0.01% manganese, 0.002 to 0.005 % Zinc and / or copper and optionally traces of boron and / or iron.

23. Device (1) according to any one of claims 16 to 22, characterized in that the plant fertilizer in a dilution 1: 50 to 1: 200, in particular in a dilution 1: 100, the original concentration in the process liquid (9) is included ,

24. Device (1) according to any one of claims 16 to 23, characterized in that the pH of the process liquid (9) from a range having a lower limit of 5, in particular 5.5, preferably 6, and an upper limit of 7.5, in particular 7, preferably 6.5, is selected.

25. Device (1) according to one of claims 16 to 24, characterized in that the process liquid (9) comprises a solvent whose polarity is between that of

Water and siloxanes are located.

26. Device (9) according to claim 25, characterized in that as solvent at least one surfactant in an amount selected from a range with a lower limit of 0.1%, preferably 0.3%, in particular 0.5% and an upper Limit of 5%, preferably 3%, in particular 1%, in the process liquid (9) is included.

27. Device (1) according to one of claims 16 to 26, characterized in that at least one distributor base (19) in the reactor (4) is arranged.

28. Device (1) according to claim 27, characterized in that the at least one distributor base (19) is designed in the form of a perforated plate.

29. Device (1) according to claim 27 or 28, characterized in that the distributor plates (19) are arranged at regular intervals along the interior (21) of the reactor (4).

30. Device (1) according to any one of claims 16 to 29, characterized in that a collecting container (8) for supplying and / or removal of the process liquid (9), metabolic products of microorganisms, etc. is arranged, in which optionally a distribution device (11), such as stirrer, is arranged.

31. Device (1) according to any one of claims 16 to 30, characterized in that the collecting container (8) has a heating device, in particular a heating jacket (16) is arranged.

32. Device (1) according to any one of claims 16 to 31, characterized in that in the flow of the process liquid (9), the biogas (2), the oxidizing agent (6) and / or the mixture thereof after the reactor (4) Droplet separator (23) is arranged.

33. Device (1) according to one of claims 16 to 32, characterized in that it has an efficiency of 80% to 90%.

34. Use of the device (1) according to any one of claims 16 to 33 for pre-cleaning and / or cleaning, in particular for the removal of siloxanes from biogas (2).

35. Use of the device (1) according to any one of claims 16 to 33 in the fermentation of biogas (2) in combined heat and power systems, in particular fuel cells.