DE102012109821A1 - Producing biogas, by providing a solid fermenter for fermenting organic solids and a liquid fermenter, adding percolate to percolation of organic solids in solid and liquid fermenters, applying percolate on organic solids in solid fermeter - Google Patents

Abstract

Producing biogas, comprises: providing at least one solid fermenter (2) for fermenting organic solids and at least one liquid fermenter (3); adding percolate to the percolation of the organic solids in the solid fermenter and the liquid fermenter; repeatedly applying the percolate on the organic solids in the solid fermeter; collecting the percolate at a bottom of the solid fermenter and feeding back into the liquid fermenter; and controlling the chemical, biological and/or physical properties of the percolate in the liquid fermenter. An independent claim is included for an apparatus for producing the biogas, comprising the solid fermenter for the digestion of organic solids, and the liquid fermenter for receiving the percolate to the percolation of the organic solid absorbed in the solid fermenter, and a unit for controlling the chemical, biological and/or physical properties of the percolate in liquid fermenter.

Description

Technical area

The present invention relates to a method and apparatus for producing biogas.

State of the art

It is known to ferment organic solids and in particular stackable biomass in so-called solid fermenters in order to obtain biogas from this. Subsequently, the biogas is usually used for heat generation and / or combined heat and power plants for the coupled generation of electricity and heat. After purification, the biogas can also be sold as biomethane and can for example be fed into the natural gas grid or used for the operation of vehicles.

In the known solid-state fermentation, the organic solids are introduced into a solid-fermenter and then periodically charged with a percolate stream. The percolate drizzled through the solid bed formed by the stackable biomass is usually collected at the bottom of the solid-fermentor, circulated, and then trickled over the stackable biomass in the respective or another solid-fermentor. The percolate stream is applied to the biomass from the top of the solids fermenter to start the fermentation process and then keep it going.

The Feststofffermenter is usually designed like a garage and has gas-tight walls, ceiling and floor, which are often poured concrete, and a gas-tight gate. In this way, anaerobic digestion of the biomass is possible. The biogas is usually withdrawn via corresponding line devices from the solid fermenters. Through the gate, the solid fermenter can be loaded with the organic solids.

After the fermentation process of a loading of a solids fermenter with organic solids is completed, that is approximately after 4-5 weeks, the digestate is discharged through the gate of the corresponding Feststofffermenter.

In the known methods, the organic solids are fermented in an anaerobic environment in the solid fermenter, wherein the correspondingly required microorganisms are supplied inter alia by means of the drizzled percolate. The organic solids are correspondingly "inoculated" by the percolate. In the solid fermenter, the organic solids are then fermented to form biogas.

The fermentation process can be divided into the following four stages: In the first stage, hydrolysis, the biomolecules present in the organic biomass are broken into fragments by reaction with water, releasing hydrogen and CO ₂ . In the second step, acidogenesis, the fragments formed in the hydrolysis are reacted on the one hand into lower fatty acids and / or carboxylic acids such as butyric acid or propionic acid, on the other hand into lower alcohols such as ethanol. In the third stage, acetogenesis, the lower fatty acids and / or carboxylic acids formed during the hydrolysis and acidogenesis and the lower alcohols are converted by acetogenic microorganisms primarily to acetic acid, or to its dissolved salt, the acetate. In the fourth stage, methanogenesis, on the one hand, acetic acid is converted to methane and carbon dioxide by acetic acid-splitting methanogens, and on the other hand, methane is formed from hydrogen and CO ₂ by another group of methanogens. The biogas resulting from this process is largely made up of methane. Accordingly, it is a high-energy gas, which is formed under the anoxic conditions from the organic solids by fermentation.

From the DE 10 2005 029 306 B4 a method for operating a Feststofffermenteranlage and a device for this purpose is known. According to the teaching of this document, the percolate flow for each intended solid fermenter is controlled so that the acid formed in the solids fermenters is flushed out with the percolate stream so that no acidification of the biomass stored in the solid fermenter occurs and at the same time the percolate flow has such a loading of microorganisms in that it can be used for starting the fermentation in a newly prepared solid-fermenter. In this case, biogas is taken from both the active solids fermenter and a continuously operating regeneration fermenter for the percolate, which serves as a percolate container.

The focus of this prior art, as well as all other known from the prior art devices for the fermentation of organic solids is the production of biogas in the Feststofffermentern. Accordingly, the percolate flow is controlled so that optimum fermentation of the organic solids in the solids fermenter is achieved.

From the WO 02/06439 A2 For example, a bioreactor for methanization of biomass and a biogas plant for generating thermal, electrical or mechanical energy from biomass with a corresponding bioreactor is known. In this application, it is described that the seepage fluids emerging from the biogas reactors designed as pit fermenters are measured with regard to their pH, their nutrient content and other important parameters. Additives are then added to the seepage fluids and the seepage fluids processed in this way are used as percolate.

Also from the DE 44 09 487 A1 is a method and a plant for the fermentation of bio-organic raw waste known, in which the leachate from a first pit fermenter for percolation of a second pit fermenter is used.

The basic idea of the known devices and methods for fermenting organic solids in solid fermenters is to optimize the gas yield in the respective Feststofffermenter or the fermenter and accordingly to control the Perkolatstrom so in terms of its chemical, biological and physical properties that the gas yield is optimized in the Feststofffermenter ,

Presentation of the invention

Based on this prior art, it is an object of the present invention to further improve the biogas yield of a device for generating biogas.

This object is achieved by the method having the features of claim 1. Advantageous developments emerge from the subclaims.

Accordingly, a method for producing biogas is proposed, wherein at least one solid fermenter for the fermentation of organic solids and at least one liquid fermenter are provided, and in the liquid fermenter percolate for percolation of the organic solids in the solid fermenter is received. The percolate is repeatedly applied to the organic solids in the solid-fermenter and the percolate is collected at the bottom of the solid-fermentor and returned to the liquid fermenter. According to the invention, the chemical, biological and / or physical properties of the percolate are regulated in the liquid fermenter.

By controlling the percolation of the organic solid in the solid-fermentor due to the properties of the percolate in the liquid fermenter, it is achieved that the chemical, biological and physical properties of percolate in the liquid fermenter are optimized for biogas production. Accordingly, the focus of the control is shifted from the known from the prior art optimization of gas production in the Feststofffermentern towards optimizing the gas generation in Flüssigfermenter over the prior art.

The properties of the percolate in the liquid fermenter can be optimized so that they are optimized for the acetogenesis, ie the fermentative conversion of the converted from the organic solids in the Acidogenese to propionic acid, fatty acids and simple alcohols nutrients, and methanogenesis. Accordingly, acetogenesis and methanogenesis preferably take place in the liquid phase in the liquid fermenter.

It is known that in acidogenesis, ie the primary acidification of the nutrients obtained by the hydrolysis to propionic acid, fatty acids and simple alcohols, bacteria, which prefer a low pH and a low temperature of below 30 ° C. These ratios can be adjusted in the solids fermenter.

In the liquid fermenter, on the other hand, the conversion of propionic acid, fatty acids and simple alcohols produced in acidogenesis is carried out by acetogenesis in acetic acid. Furthermore, here the methane formation from the acetic acid by the archaea, which prefer a high pH and higher temperatures between 39 ° C and 40 ° C at preferably anaerobic environmental conditions carried out. These environmental conditions can be adjusted accordingly in the liquid fermenter. Accordingly, optimum conditions can be set in the solid-fermenter for the hydrolysis and the primary acidification (acidogenesis), and optimal conditions can also be set for the acetogenesis and the methanogenesis in the liquid fermenter.

Of course, all processes run parallel to each other, both in the solid-fermenter and in the liquid fermenter. Accordingly, biogas production takes place both in the solid-fermenter and in the liquid fermenter. By adjusting the ambient conditions accordingly, however, a corresponding center of gravity can be produced in the solid-matter fermenter and in the liquid fermenter.

The chemical, biological and / or physical properties of the percolate in the liquid fermenter are preferably regulated in such a way that they are stable in the liquid fermenter predetermined value ranges are maintained in order to achieve optimized biogas production in the liquid fermenter.

The chemical, biological and / or physical properties of the percolate in the liquid fermenter can be regulated by controlling the frequency, volume and / or duration of percolation of the organic solids in the solid-fermenter. In other words, when falling below or exceeding certain values of the percolate in the liquid fermenter, a corresponding percolation of the organic solids in the solids fermenter takes place in order to move the values back into the desired range after the percolate has been returned to the liquid fermenter by the percolate which has been seeped by the organic solids. In this way, the chemical, biological and / or physical properties of the percolate in the liquid fermenter trigger the percolation of the organic solids in the solid-state fermenter.

Preferably, the percolation of the organic solids in the Feststofffermenter when a certain pH, a certain temperature, a certain concentration of the dry matter of the percolate in the solid fermenter and / or in the presence of a certain FOS / TAC value of the percolate in the solid fermenter is triggered to the return the corresponding values to the target value range.

Under FOS thereby volatile organic acids, which are measured in the unit mg / l acetic acid equivalent. TAC is the total inorganic carbonate (the alkaline buffer capacity), which is measured in mg / CaCo ₃ / l. The FOS / TAC value is known as the guide value for fermentation processes.

The chemical, biological and / or physical conditions for the percolate in the solid-fermenter are preferably controlled in such a way that an optimum biogas production production is achieved in the liquid fermenter.

It has been shown that by regulating the chemical, biological and physical properties of the percolate in the liquid fermenter, the gas yield can be optimized. In particular, by providing relatively low concentrations of dry matter in the liquid fermenter, a particularly high biogas yield can be achieved.

Accordingly, the concentration of the dry matter in the percolate in liquid fermenter by a corresponding control of percolation of the organic solid in the solid fermenter in a range of 0.5 to 5 wt .-%, preferably in the range of 1 to 3 wt .-%, particularly preferably in Range of 2 wt .-% held. In other words, the percolation of the solid-fermentor is controlled based on a corresponding measurement of the dry matter concentration in the liquid fermenter such that flushing the corresponding dry solids from the solid-fermenter gives such an input of dry matter to the liquid fermentor that maintains the desired dry-matter concentration in the liquid fermenter becomes.

This concept was neither proposed nor contemplated in the prior art. In the prior art, rather, a contrary control process is always used, namely an optimization of the conditions of methanogenesis in the solid fermenter, wherein the conditions are not considered in the liquid fermenter.

In a further advantageous variant, the regulation of the chemical, biological and / or physical properties of the percolate in the liquid fermenter is regulated by adjusting the ratio of the volume of percolate in the liquid fermenter to the base of the active solid fermenter with simultaneous percolation, wherein the ratio of the volume of liquid fermenter is set to the base of the active solid fermenter at about 0.5 to 1.5, preferably at 0.8 to 1.2. This results in comparison with the systems known from the prior art, a significantly increased volume of Flüssigfermenters.

By providing a corresponding base area of the organic solids to be fermented and the volume in the liquid fermenter can be achieved that both the solid fermenter and the Flüssigfermenter can be operated optimally. By such an interpretation of the overall system, an optimization can be correspondingly achieved in that not only an optimized gas yield in the solid fermenter can be achieved, but also a significantly optimized gas yield is achieved in the liquid fermenter. This is achieved by an optimized percolation of the organic solids in the solid fermenter with at the same time adequate entry of dry matter into the liquid fermenter in such a way that an optimized concentration of dry substance is maintained in the liquid fermenter.

In a further preferred variant of the method, in addition to the liquid fermenter, an overflow container is provided in which excess percolate volume is taken up. In the digestion or fermentation of the organic solid in the Feststofffermenter water is released, which contributes to a corresponding increase in volume. This increased volume can be absorbed in the overflow tank. Also in the overflow tank is still a biogas production.

Accordingly, the overflow tank is suitable for biogas production. In a preferred further method step, liquid raw materials, such as liquid manure, can be fed into the overflow container in order to continue to allow biogas production here. However, a direct entry of the liquid raw materials into the percolate container is not desired and is not intended to keep the optimization of the biological, chemical and physical properties of the percolate in the percolate tank, and in particular the relatively low content of dry matter in this range.

The overflow container then behaves essentially like a conventional liquid fermenter, which is inoculated by the overflowing percolate. The overflow container is also preferably formed with a stirring system to allow the inclusion of additional liquid raw materials.

The method further offers the possibility of carrying out an aerobic hydrolysis, in that the organic solids without air exclusion, for example, with open door of the solid fermenter are trickled only with percolate or process water, and the corresponding dissolved nutrients then fed to the actogenesis and methanogenesis in the liquid fermenter become. This results in a simplified handling of the organic solids.

The percolate also serves to control the ion exchange in the organic solids, to transfer temperature and to supply nutrients to the liquid fermenter.

The percolate in this case has a high inhibitor tolerance, which is formed by active base exchange or ion exchange on the solid bed of organic solids. For example, nitrogen and sulfur can remain in the solid bed in this way, since the anions from the hydrolysis and the fermentation substrate are exchanged with the cations from the percolate and corresponding nutrient salts remain in the organic solid bed (s). This has advantages in the subsequent use of the digestate from the organic solids, as results in a high quality compost, which requires no further nutrient enrichment. Furthermore, the inhibitors are not enriched in the percolate, so that the methanogenesis is not hindered in Flüssigfermenter.

In a further preferred method step, the digestate is pressed out after the end of fermentation in order to achieve percolate recovery. Accordingly, the digestate is removed from the corresponding Feststofffermenter and subjected to a pressing process, so that 60% to 80% of the still present in the digestate percolate are removed from the digestate and this percolate is then fed back to the liquid fermenter. In this way, the yield increases further, as well as the present in the digestate percolate can be used to produce biogas.

The fermentation residue can then be deposited on a corresponding sanitation surface on which it is blown from below with hot air, for example the waste air from a cogeneration plant connected to the biogas plant, in order to completely sanitize the fermentation residue. In this way, the moisture content of the finished compost can be determined by adjusting the residence time, and this can reach down to dry pellets.

In a preferred method, the fermentation residue or the compost is continuously circulated and reacted via a screw conveyor, so that the digestate passes through a certain conveying section within the hygienisation device. The residence time is adjustable via the delivery rate of the screw conveyor. Accordingly, a continuous process can be provided in this way by means of which the compost can be conveyed from its original, relatively moist consistency, originating from the press, to a sanitized and dried consistency.

In a further preferred embodiment, nutrients can then be added to the compost, so that a compost specially designed for specific purposes or agricultural areas is achieved. For example, different agricultural areas require a different phosphate input. Accordingly, a compost can be produced on the same plant, which is suitable for immediate extension to the respective agricultural area and which offers a corresponding adapted to the respective agricultural area nutrient entry.

The above object is also achieved by a device having the features of claim 11. Advantageous developments emerge from the subclaims.

Accordingly, the device for generating biogas comprises at least one solid fermenter for the fermentation of organic solids, and a liquid fermenter for receiving a Percolates for percolating the organic solids collected in the solid-fermentor. According to the invention control means are provided for controlling the chemical, biological and / or physical properties of the percolate in the liquid fermenter.

Advantageously, the control means comprise at least one sensor for measuring biological, chemical and / or physical properties of the percolate in the liquid fermenter and an adjustable percolate valve and / or an adjustable percolate pump are provided for the controlled percolation of the organic solids contained in the solid-fermenter such that the properties of the percolate are optimized in the liquid fermenter for biogas production.

Brief description of the figures

Preferred further embodiments and aspects of the present invention are explained in more detail by the following description of the figures.

1 schematically shows a device for generating biogas by means of the described method;

2 schematically shows a press for pressing the percolate from the digestate; and

3 shows schematically a device for the treatment of the fermentation residue for the production of compost.

Detailed description of preferred embodiments

In the following, preferred embodiments will be described with reference to the figures. In this case, identical, similar or equivalent elements in the different figures are denoted by identical reference numerals and a repeated description of these elements is partially omitted in order to avoid redundancies in the description.

In 1 is a device 1 to carry out the process for the production of biogas shown.

A solid fermenter 2 with a first solid fermenter box 20 and a second solid fermenter box 22 is intended to contain organic solids for fermentation therein. The solid-fermenter boxes 20 . 22 are constructed in a known manner and have in particular gas-tight walls, floors and ceilings, as well as a gas-tight closing gate through which the respective Feststofffermenterbox 20 . 22 is charged with organic solids and by which the fermentation residue is cleared after completion of the fermentation process again.

Furthermore, a liquid fermenter 3 provided in which percolate can be added and which serves as Perkolatspeicher accordingly. The percolate is trickled over the enclosed in the respective Feststofffermenterboxen organic solids via ceiling nozzles.

From the liquid fermenter 3 is via the percolate line 42 Perkolat so in the respective solid fermenter boxes 20 . 22 Passed that over it to the ceiling of the solid-fermenter boxes 20 . 22 provided Perkolatdüsen on the organic solids, which within the Feststofffermenterboxen 20 . 22 are arranged, can be drizzled. The percolate then collects at the bottom of the solid fermenter boxes 20 . 22 after it has passed through the organic solids.

Therefore, the solid fermenter boxes are 20 . 22 in their bottom area via a corresponding Perkolatleitung 40 with the liquid fermenter 3 connected so that on the bottom of each solid fermenter box 20 . 22 Collected percolate over the percolate line 40 back to the liquid fermenter 3 can be directed.

Accordingly, a Perkolatkreislauf is given, the percolate from the liquid fermenter 3 over the percolate line 42 into the solid-fermenter boxes 20 . 22 is sprinkled, and after passing through the organic solid at the bottom of the Feststofffermenterboxen 20 . 22 is collected and via the percolate line 40 again the liquid fermenter 3 is supplied.

Furthermore, there are biogas pipes 50 and 52 provided by means of which in the Feststofffermenterboxen 20 . 22 Biogas produced can be derived. In addition, a biogas line 53 provided by means of which in the liquid fermenter 3 resulting biogas can be derived.

Furthermore, a biogas line 56 provided by means of which the biogas, which in an overflow container 6 is also derived. The overflow tank 6 serves to remove excess percolate from the liquid fermenter 3 take. For example, excess percolate is produced in the fermentation process by producing water during fermentation. Furthermore, water volumes are introduced into the percolate circulation via the organic solids.

The about the biogas pipes 50 . 52 . 53 . 56 derived biogas will subsequently either directly in a combined heat and power plant (CHP) converted into electricity and heat, or it is purified and placed accordingly as biomethane in the market.

The chemical, physical and / or biological properties of the percolate in the liquid fermenter are determined by means of a corresponding sensor 7 measured. The sensor 7 For example, it can measure the dry matter content, pH, temperature, FOS / TAC, and other parameters that are important for fermentation.

Based on the over the sensor 7 measured parameter of the liquid fermenter 3 recorded percolate is correspondingly via a control device 72 a percolate valve 70 or a corresponding Perkolatpumpe driven. A percolation of the in one or both of the solid-fermenter boxes 20 . 22 arranged organic solid is then triggered when falling below or exceeding a certain limit, such that by the triggered percolation and the corresponding re-entry of the in the Feststofffermenterboxen 20 . 22 collected percolate in the liquid fermenter 3 the corresponding desired, chemical, physical or biological properties in the liquid fermenter 3 can be restored.

The delay, which results from the percolation through the organic solid as well as the collection of percolate at the bottom of the solid fermenter, can already be taken into account within the prescribed limits. In one variant, the measured parameters and the behavior of the percolate in the liquid fermenter 3 be extrapolated by means of a corresponding analysis device. In both cases, the percolation of the organic solid in the Feststofffermenter 3 so controlled that the parameters of percolate in the liquid fermenter 3 move in the desired area.

It should be noted that the dry matter in the liquid fermenter 3 is converted into biogas on a significantly different time scale than the dry matter in the solid-fermenter 1 , Typical times are approx. 5 hours for complete reaction in the liquid fermenter 3 against a residence time of the organic solids in the Feststofffermenter 1 from about 28 to 35 days.

By percolation of the organic solids in the solid-fermenter controlled in the above manner 1 is accordingly for a steady supply of dry matter in the liquid fermenter 3 taken care so that the liquid fermenter 3 can always be operated at the optimum operating point and accordingly a high and optimized biogas yield in the liquid fermenter 3 takes place.

The in 1 The feedback control mechanism shown can be greatly simplified if the desired physical, chemical or biological properties of the percolate in the liquid fermenter 3 can be achieved even at a fixed percolation rate. This is achieved, for example, by having a certain ratio between the volume of the liquid fermenter 3 and the footprint (and thus volume) of the respective active solid fermenter boxes 20 . 22 will be produced. For a corresponding base area of the solid-fermenter boxes 20 . 22 At a fixed Perkolierungsrate, for example, a certain Percolation time per hour, a corresponding nutrient input into the liquid fermenter 3 achieved such that the desired parameters in the liquid fermenter 3 be achieved. For example, in this way a predetermined concentration of dry matter in the liquid fermenter 3 be maintained in such a way that an optimal implementation of the dry matter in the liquid fermenter 3 , and thus optimized biogas production can be achieved. Accordingly, the percolation is also based on parameters of the percolate in the liquid fermenter 3 controlled so that a given concentration of dry matter in the liquid fermenter 3 can be maintained.

Accordingly, there are at least two different possibilities for carrying out the method, namely on the one hand via an active feedback control via the sensor 7 and a control device 72 , which according to a percolate valve 70 or controlling a percolate pump, or at a fixed percolation rate, by establishing suitable footprints of the active solid fermenter boxes 20 . 22 with respect to the volume of the liquid fermenter 3 ,

Under volume of liquid fermenter 3 Here, the volume understood, which is intended to receive the percolate. The volume of the liquid fermenter 3 typically results from its base times times a filling height, which is predetermined by an overflow device.

In the overflow tank 6 There is a further fermentation of the gradually overflowed percolate, so that here, too, a generation of biogas is achieved. This generation of biogas can be further supported by the fact that the overflow tank 6 is designed as a complete liquid reactor and, for example, depending on the application, is also provided with a stirrer and with a heater.

Into the overflow tank 6 can continue directly liquid or liquefied biomass, such as manure, via an inlet 60 be filled. By introducing the liquid biomass into the overflow tank 6 can be achieved with the said plant and a processing of liquid biomass, wherein the liquid biomass in the overflow tank 6 through the liquid fermenter 3 overflowing percolate is inoculated. The overflow tank 6 then works like a conventional liquid fermenter, depending on the introduced liquid raw material. In the overflow tank 6 At the introduction of the liquid biomass, there is no special control of the concentrations of the liquid, but instead the liquid biomass is fed after seizure or need, as in a conventional liquid fermenter.

Due to the fact that the liquid biomass does not enter the liquid fermenter 3 can be introduced in the liquid fermenter 3 continue to be maintained optimal conditions for the fermentation of dry matter, so that the main part of biogas production in the liquid fermenter 3 takes place. Nevertheless, liquid or liquefied biomass can be processed with the plant, namely in the overflow tank 6 ,

It has been found that the control of the organic solids fermenting apparatus in the manner indicated, namely that in the liquid fermenter 3 arranged percolate is optimized for gas production, leads to particularly advantageous gas yields. Accordingly, in the liquid fermenter 3 Environmental conditions are created, which are optimized for the fermentation or the production of biogas, for example, by setting a relatively high pH and higher temperatures of 39 ° C to 40 ° C such that the archaea, which mainly for the methane formation from the Acetic acid, show a high degradation performance. Biogas production in the solid-fermenter boxes 20 . 22 is not necessarily operated at the optimum, here the process is rather for the hydrolysis and acidogenesis, ie the primary acidification to propionic acid, fatty acids and simple alcohols out optimized, the corresponding products then on the trickling percolate and the percolate line 40 in the liquid fermenter 3 be rinsed.

In 2 is again schematically the solid-fermenter 2 shown, from which the digestate 8th after completion of the fermentation in a press 80 is introduced. In the press 80 is by means of a corresponding pressing device 82 the digestate 8th squeezed out and corresponding to that still in the digestate 8th pressed percolate pressed. The appropriately pressed percolate is collected and passed over a percolate line 84 the liquid fermenter 3 fed again. In this way, the yield of biogas can be further increased because no percolate is lost and the last still fermentable components of the digestate 8th be withdrawn.

By pressing a correspondingly expressed or increased in its dry content digestate is generated. Preference is given to the digestate 8th while pressing still 60% to 80% of the digestate 8th withdrawn percolate. In this way, an efficient use of the percolate can be achieved, so that the yield increases, since the last percolate residues can be used for biogas production. Furthermore, in this way a relatively dry digestate 8th produced, which can be converted into dried compost or heating pellets with relatively less energy.

3 shows schematically the expressed digestate 8th which is on a device for sanitization 9 and is set up for compost preparation. The device for sanitation 9 has a variety of hot air nozzles 90 on, through which hot air from below into the digestate 8th blown. The hot air from the hot air nozzles 90 serves to digest the digestate 8th to dry and keep for a predetermined time at a Hygienisierungstemperatur so that it can be subsequently applied again as organic fertilizer or compost on an agricultural area. The hot air can, for example, as exhaust air from a combined heat and power plant 92 incurred, so that there are no additional costs for the heating of the hot air.

A constant mixing as well as a conversion of the digestate 8th takes place by means of a screw conveyor 94 instead, which continuously ruminates the digestate and converts it due to their capacity so that the digestate 8th in 3 wanders from left to right. By the appropriate setting of the screw conveyor 94 with respect to the flow rate and their slope, the residence time of the digestate 8th in the sanitation device 9 be set.

This results in a hygienized compost with a defined liquid content. Subsequently, from this compost still impurities, such as metallic objects, are separated, and the compost can then be spent on an agricultural area.

In a preferred embodiment, in addition, via an admixing device 96 Nutrients in the digestate 8th be introduced, for example, phosphate to produce a corresponding compost, which to the respective Agricultural area is adjusted. For example, in the case of a lack of phosphate in a utilized agricultural area, the additional introduction of phosphate into the fermentation residue during the sanitation process or even thereafter a corresponding design compost can be achieved, which is adapted to the nutrient requirement of the respective agricultural area.

Where applicable, all individual features illustrated in the individual embodiments may be combined and / or interchanged without departing from the scope of the invention.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102005029306 B4 [0008]
• WO 0206439 A2 [0010]
• DE 4409487 A1 [0011]

Claims (15)

Process for producing biogas, wherein at least one solid fermenter ( 1 ) for the fermentation of organic solids and at least one liquid fermenter ( 3 ) and in the liquid fermenter ( 3 ) Percolate for percolation of the organic solids in the solid-fermenter ( 2 ), the percolate is repeated on the organic solids in the solid-state meter ( 2 ) and the percolate at the bottom of the solid fermenter ( 2 ) and recycled to the liquid fermenter, characterized in that the chemical, biological and / or physical properties of the percolate in the liquid fermenter ( 3 ) be managed. Process according to Claim 1, characterized in that the chemical, biological and / or physical properties of the percolate in the liquid fermenter ( 3 ) are regulated so that they are kept in predetermined value ranges. Process according to claim 1 or 2, characterized in that the chemical, biological and / or physical properties of the percolate in the liquid fermenter ( 3 ) by regulating the frequency, volume and / or duration of percolation of the organic solids in the solid-fermenter ( 2 ) be managed. Process according to one of the preceding claims, characterized in that the percolation of the organic solids in the solid fermenter ( 3 ) upon reaching a certain pH, a certain temperature, a certain concentration of the dry matter of the percolate in the solid-fermenter ( 3 ) and / or in the presence of a specific FOS / TAC value of the percolate in the solid fermenter ( 3 ) is triggered. A method according to any one of the preceding claims, characterized in that the chemical, biological and / or physical conditions of the percolate in the solids fermenter ( 3 ) are regulated so that in the liquid fermenter ( 3 ) an optimal biogas production production is achieved. Process according to one of the preceding claims, characterized in that the concentration of the dry matter in the percolate in the liquid fermenter ( 3 ) by a corresponding regulation of the percolation of the organic solid in the solid fermenter ( 2 ) in a range of 0.5 to 5 wt .-%, preferably a range of 1 to 3 wt .-%, more preferably in the range of 2 wt .-% is maintained. Method according to one of the preceding claims, characterized in that the control of the chemical, biological and / or physical properties of the percolate in the liquid fermenter ( 3 ) by adjusting the ratio of the volume of percolate in the liquid fermenter ( 3 ) to the base of the active solid fermenter ( 2 ) is controlled simultaneously with periodic percolation, the ratio of the volume of the liquid fermenter ( 3 ) to the base of the active solid fermenter ( 2 ) is adjusted at about 0.5 to 1.5, preferably at 0.8 to 1.2. Method according to one of the preceding claims, characterized in that the liquid fermenter ( 3 ) with an overflow container ( 6 ) and liquid substrates into the overflow tank ( 6 ) are introduced. Process for producing biogas, wherein at least one solid fermenter ( 1 ) is provided for the fermentation of organic solids, preferably according to one of the preceding claims, characterized in that the digestate ( 8th ) after completion of the fermentation process in the solid-fermenter ( 2 ) is pressed out to recover the percolate contained in the fermentation residue and the pressed-out percolate is returned to the liquid fermenter ( 3 ) is supplied. Process for producing biogas, wherein at least one solid fermenter ( 1 ) is provided for the fermentation of organic solids, preferably according to one of the preceding claims, characterized in that the digestate ( 8th ) after completion of the fermentation process in the solid-fermenter ( 2 ) is blown through with hot air for sanitization and / or drying, preferably for the production of a sanitized compost. Contraption ( 1 ) for the production of biogas comprising at least one solid fermenter ( 2 ) for the fermentation of organic solids, as well as a liquid fermenter ( 3 ) for receiving a percolate to percolate in the solid fermenter ( 2 ) recorded organic solids, characterized in that control means for controlling the chemical, biological and / or physical Properties of percolate in the liquid fermenter ( 3 ) are provided. Device according to claim 11, characterized in that the control means comprise a sensor ( 7 ) for measuring biological, chemical and / or physical properties of the percolate in the liquid fermenter ( 3 ) and a controllable percolate valve ( 70 ) and / or an adjustable percolate pump are provided for the controlled percolation of the in the Feststofffermenter ( 2 ) such that the properties of the percolate in the liquid fermenter ( 3 ) are optimized for biogas production. Device according to claim 11 or 12, characterized in that the volume of the liquid fermenter ( 3 ) in a ratio of 0.5 to 1.5, preferably 0.8 to 1.3 to the base of the active solid fermenter ( 2 ) stands. Device for producing biogas with at least one solid fermenter ( 2 ) for the fermentation of organic solids, preferably according to one of claims 11 to 13, characterized in that a press ( 80 ) for pressing out the digestate ( 8th ) is provided such that the digestate ( 8th ) 60% to 80% of the percolate contained after fermentation can be squeezed out. Device for producing biogas with at least one solid fermenter ( 2 ) for the fermentation of organic solids, preferably according to one of claims 11 to 14, characterized in that the sanitizing device ( 9 ) is provided, by means of which for the hygienization of the digestate ( 8th ) hot air into the digestate ( 8th ) can be blown.

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