WO2009071053A2

WO2009071053A2 - Device and method for producing biogas from organic matters

Info

Publication number: WO2009071053A2
Application number: PCT/DE2008/001956
Authority: WO
Inventors: Günter Perske
Original assignee: Eltaga Licensing Gmbh
Priority date: 2007-12-07
Filing date: 2008-11-25
Publication date: 2009-06-11
Also published as: DE102007058967A1; EP2268787A2; WO2009071053A3

Abstract

The invention relates to a device for producing biogas from organic matters, comprising a biogas reactor (210) forming at least one chamber (220, 230, 232), wherein a defined mixture made of fresh substrate comprising organic matters and recirculate comprising organic matters can be supplied to said biogas reactor via a mixing unit (286). According to the invention a controller is provided, which is suited to control a supply of the recirculate and/or of the fresh substrate to the mixing unit (286) at least as a function of a variable correlating with a fresh substrate composition of the fresh substrate supplied to the mixing unit (286) in order to obtain the defined mixture. In addition, the invention also relates to a corresponding method for producing biogas from organic matters.

Description

Apparatus and method for producing biogas from organic matter

The invention relates to a device for the production of biogas from organic materials, with a at least one chamber forming biogas reactor, via a mixing unit, a defined mixture of organic substances having fresh substrate and an organic material having recirculate can be fed.

Furthermore, the invention relates to a method for producing biogas from organic substances by a biogas plant comprising a biogas reactor forming at least one chamber to which a defined mixture of fresh substrate having organic substances and recirculating material containing organic substances is supplied via a mixing unit.

Usually, it is necessary to prepare so-called fresh fermentation substrates accordingly, in order to then supply these processed fresh fermentation substrates to a biogas plant or a biogas reactor for the production of biogas. In the biogas plant, in particular in a reactor space of the biogas plant or of the biogas reactor, the biogas is then usually produced in a plurality of chambers of the reactor space which are coupled to one another. Such a reactor space may comprise, for example, a filling chamber and a plurality of intermediate chambers. The device for the production of the finished fermentation Substrate or the Frischgärsubstrats is usually coupled to the filling chamber of the reactor space, preferably a heat exchanger of the biogas plant between the filling chamber and the apparatus for producing the finished fermentation substrate may be arranged to a suitable temperature of the finished fermentation substrate for the production of biogas in the To get reactor space. The heat exchanger is usually followed by a mixing unit, which is thus arranged between the heat exchanger and the biogas reactor or the reactor space. Finally, the mixture is fed to the reactor space from the mixture of the finished fermentation substrate, namely the fresh substrate, and the recirculate. The recirculate comprises organic substances which have at least partially already passed through or flowed through the biogas reactor or the reactor space and are fed to the mixing unit for the production of the aforementioned mixture and thus re-supplied to the biogas reactor. In particular, therefore, the recirculate is predominantly nonreactive organic matter. In biogas production, anaerobic bacteria are used to decompose organic substances that are no longer associated with the living organism and convert them into gas. Anaerobic bacteria are the last link in the natural cycle and occur everywhere in nature, for example in stomachs of ruminants or in the black mud of lakes and bogs. In anaerobic digestion, the facultative methane bacteria and the obligate methane bacteria are to be distinguished first. The organic substances used as raw materials in anaerobic digestion include, for example, organic substances or residues from industry, gastronomy, trade, agriculture (manure and solid manure) or renewable raw materials (maize). grass silage and other short-shrubs). These organic substances mainly consist of carbohydrates, fats and proteins. The optional, optional methane bacteria can also live with oxygen. These take over a first phase of treatment and decompose the organic substances into alcohols, fatty acids and their salts. This first phase of the treatment is referred to as the acid generator phase or hydrolysis. In a second phase, the obligate methane bacteria convert into alcohols, fatty acids and their salts into gas. This second phase is called the methanation phase. The first and second phases are delayed by approximately six hours, with the so-called hydrolysis phase occurring during the first six hours.

FIG. 1 shows a diagram which represents the general course of natural fermentation. In particular, the diagram shows the reduction of an organic dry matter (OTS) in percent as a function of the elapsed days (full line). It should be noted that during the first twenty days, the degradation of the dry matter is very slow going. Only a few bacteria, as present in all organic wastes, develop in the logarithmic ratio (dashed line) with the appropriate feed supply. In the same proportion as the bacteria develop, the organic matter is degraded and converted into gas. Desirable is a degradation of the organic dry matter of 70 percent, but this is approximately reached after 40 days according to the diagram of Figure 1 in the natural fermentation process.

Biogas plants aim to create an environment for organic fermentation, which enables these organic nical fermentation is significantly accelerated. However, there is generally the problem in biogas technology, in particular in the biogas plants belonging to the state of the art, that in particular the anaerobic processes in these biogas plants do not occur to the intended or desired extent. In order for such anaerobic processes or processes, in particular within the framework of an anaerobic biocenosis, to proceed to a suitable extent, it is necessary on the one hand to determine suitable framework conditions in the biogas plant in a suitable manner. On the other hand, the composition of the finished fermentation substrate (Gärmasse), the fresh substrate, is of particular importance in order to favor the anaerobic processes in the biogas plants. This means that in the production of the substrate or the fresh substrate prepared for the biogas plant, particular attention must be paid to its composition, in order subsequently to achieve the desired anaerobic processes in the biogas plants with the addition of the recirculate. It is generally known that a balance of carbon and nitrogen (C / N ratio) should be taken into account in connection with the composition of the substrate; Specific details as to which binding, balanced C / N ratio these two substances or chemical elements must have in the substrate have not yet been made. Only inaccurate information indicates that C / N ratios between 10 and 30 are desirable. Furthermore, it was also found in this context that inhibitions with respect to a bacterial culture occur with all probability at lower or exceeded these C / N ratios. Since all organic substances comprise at least three basic building materials, namely carbohydrates, fats and proteins, the two chemical elements are carbon C and nitrogen N in each case also in the substrate or the fermentation mass. However, it is extremely problematic to estimate the amounts of carbon C and nitrogen N of the individual organic masses in the substrates, and consequently also exact mixing of the individual organic substances or materials of the substrate to achieve a specific, precisely tailored composition of the substrate is extremely difficult is. In order to achieve this particular precise composition, the corresponding substrate would have to be analyzed in the laboratory, for example, in order to gain knowledge of its composition and to carry out further mixing steps based thereon. However, such laboratory analyzes are very complicated and therefore extremely expensive. Furthermore, results of such laboratory analyzes are available only after a long period of time, usually only after about 3 weeks, in which the substrate may have already changed in a sustainable manner with respect to the anaerobic processes.

Conventional substrates are produced according to the prior art, for example on the basis of silage maize, a food which is obtained as a chaff at harvest.

In particular, problems arise from the state-of-the-art devices for producing the ready-prepared fermentation substrate in that the ready-prepared fermentation substrate or the fresh substrate is in particular not adequately prepared for the anaerobic fermentation process in the biogas plant, which has lasting effects on the anaerobic symbiosis in the reactor space of the biogas plant. It is therefore the object of the present invention to develop the generic devices for generating biogas and the generic method for biogas production in such a way that a higher gas yield can be achieved.

This object is solved by the features of the independent claims.

Advantageous embodiments and modifications of the invention will become apparent from the dependent claims.

The device according to the invention for producing biogas from organic substances builds on the generic state of the art in that a control device is provided which is suitable for supplying the recirculate and / or the fresh substrate to the mixing unit at least as a function of one with a fresh substrate composition of the To control the mixing unit supplied fresh substrate korrelierenden size to obtain the defined mixture. The device according to the invention is preferably supplied with a ready-prepared fermentation substrate or fresh substrate made of straw and animal waste, in particular the mixing unit of the device according to the invention, which are largely free from harmful substances. The ready-prepared fermentation substrate supplied to the at least one chamber of the biogas reactor is preferably pumped in cycles via the mixing unit in cycles and thereby circulated. This volume-controlled cycle can be optionally and selectively threaded between two cycles of ready-made fermentation substrate. The amount of fermentation substrate or recirculate pumped in the cycle in the biogas reactor is clearly defined, with the cycle at the mixing unit ends, in which the biogas reactor, the mixture of the finished fermented substrate or fresh substrate and the recirculate is recycled. This ensures that the anesthetic symbiosis is not disturbed or impaired. For example, the fresh substrate or the finished fresh substrate can be prepared by a tumbler mixer. Thus, the filling of the free fall mixer is preferably carried out with straw chaff and thin liquid manure and solid manure (in particular animal excrement) or other organic substances. A rotatable drum of the tumble mixer is closed hydraulically sealing or fluid-tight by a full flap. This is followed by a short mixing phase in which the liquid, in particular the liquid manure, is completely bound by the solids such as the solid manure and the animal excrement. Subsequently, a suction takes place by means of a rotating vacuum pump up to about 913mbar. The anaerobic phase is thus initiated and the fresh fermentation substrate is pumped by means of an eccentric screw pump into the closed heat exchanger upstream of the biogas plant and heated to reactor temperature and pumped temperature-controlled into the biogas reactor or the reactor space via the mixing unit. At the same time recirculate is fed to the Frischgärsubstratstrom in the mixing unit according to the recipe, so that then prevails in the reactor space a preferred for anaerobic bacteria environment. In particular, the recirculate is added in dependence on the composition of the fresh substrate, which is determined by the control device; However, it is also conceivable that the control device constantly records the composition of the prepared fresh substrate and changes or fluctuations in the fresh substrate composition continuously adjusts the addition of recirculate to the mixing unit. With knowledge of the composition of the fresh substrate, the quantity-controlled addition of the recirculate and / or the fresh substrate can be precisely defined or predetermined, for example, on the basis of characteristic curves determined by tests. For example, it can be determined by experiments which C / N ratio in the fresh substrate of a certain amount is present in certain fresh substrate compositions and recorded in characteristic curves. Based on these characteristics, it can thus be determined by further experiments which quantities of recirculatate are to be mixed with the specific amount of fresh substrate in the mixing unit in order to obtain the desired C / N ratio. With particular preference, this control generates a mixture of fresh substrate and recirculate which has a C / N ratio in the range from 15: 1 to 25: 1, preferably 19: 1 to 21: 1 and particularly preferably 20: 1. In this case, this mixture has this C / N ratio after the mixing together of the fresh substrate and the recirculated lats in the mixing unit immediately before entering the

Biogas reactor on. With particular preference, this mixture then has a pH of greater than 7. With the device according to the invention, any required ready-prepared fermentation substrate can be produced. For example, pig manure, chicken manure or other organic wastes may be used. Decisive in this context, for example, the recipe or the composition of the Frischgärsubstrats and the amount of the supplied recirculate. In order to obtain a mixture in the mixing unit which has the particularly preferred C / N ratio of 20: 1 and has a pH of greater than 7, the following are in particular the following feed quantities or feed ratios as well as fresh substrate compositions conceivable, which can be adjusted by the control device on the basis of the characteristics. For a daily entry into the biogas reactor of 12 tons (12 t / d) of fresh substrate, a composition of the fresh substrate of 10.75 tons / day of manure and 1.245 tons / day of straw is set. This corresponds in parts by weight 89.60 weight percent cattle slurry and 10.40 weight percent straw, in particular straw chop. Such a fresh substrate then has approximately a C / N ratio of 46.6: 1. On the basis of the aforementioned characteristics, the control device controls the recirculation feed into the mixing unit, which is set at approximately 5.7 tons / day (t / d), whereby in the mixing unit the particularly preferred C / N ratio of 20: 1 in the mixture is achieved from fresh substrate and recirculate. In the case of a fresh substrate composition of 9.6 t / d cattle slurry, 0.9 t / d straw and 1.5 t / d of cattle manure, ie 80% by weight of cattle manure,

7.5% by weight of straw and 12.5% by weight of cattle manure, a recirculation feed of 4.7 t / d is set in the mixing unit by the controller to set the C / N ratio of 40.40: 1 in the fresh substrate to C / N. Adjust N-ratio of 20: 1 in the mixture of the fresh substrate and the recirculate. In the case of a fresh substrate composition of 10.75 t / d pig slurry and 1.245 t / d straw, i. 89.60 weight percent pig spout and 10.40 weight percent straw, a recirculation feed of 2.9 t / d is set in the mixing unit by the controller to set the C / N ratio of 33.14: 1 in the fresh substrate to a C / N ratio. Adjust N-ratio of 20: 1 in the mixture of the fresh substrate and the recirculate. In the case of a fresh substrate composition

9.6 t / d pig manure, 0.9 t / d straw and 1.5 t / d pig manure, ie 80% by weight pig manure, 7.5% percent straw and 12.5 weight percent pig manure, a recirculation feed of 1.4 t / d is set in the mixing unit by the controller to set the C / N ratio of 25.0: 1 in the fresh substrate to a C / N ratio of 20: 1 in the mixture of the fresh substrate and the Rezirku- lat. The few previous values have been determined by extensive experiments, the substrate compositions were achieved in this case using a free fall mixer with suction of air.

The device according to the invention can be developed in an advantageous manner such that the control device is suitable for determining weight percentages of corresponding components of the fresh substrate and for controlling the supply of the recirculate and / or the fresh substrate to the mixing unit on the basis of this determination. For example, when using the vertical mixer, a weighing device may be provided, via which the corresponding weight of the supplied straw chaff and the manure and the

Festmists can be determined; for example, by the supply of straw chaff and manure / solid manure being offset in time, so that a corresponding increase in weight of the Frischgärsubstratgemisch located in the vertical mixer can be continuously determined and thus can be concluded on the percentage of the corresponding Gärsubstratkomponenten. Preferably, the weighing device is programmable and mounted without contact on the vertical mixer. Unadulterated data is thus guaranteed. In addition, the fermentation substrate mixer or the mixing unit can also have a weighing device, which is connected to a control circuit and is set up to exchange data with a control circuit. ner control device, such as a personal computer (PC) to perform. In particular, the filling of the vertical mixer by weight in straw and solid manure and flow rate in the liquid manure, from which the weight can be derived, be made. An emptying of the vertical mixer, for example, via a speed control to the Exenterschne- ckenpumpe, which in turn is coupled to the heat exchanger done. Any means known in the art for directly or indirectly sensing the weight or weight proportions of the components of the fresh substrate may be used so that the exact fresh substrate composition can be determined.

Furthermore, the device according to the invention can be designed such that the control device is suitable for controlling the supply of the recirculation and / or the fresh substrate to the mixing unit in such a way that a C / N ratio of 20: 1 is established in the defined mixture. As already mentioned, the C / N ratio of 20: 1 is particularly preferred and contributes in a particularly advantageous manner to an increased gas yield in the biogas plant, as has been proven by experiments. However, C / N ratios in the range of 15: 1 to 25: 1, preferably 19: 1 to 21: 1, are tolerable in terms of gas yield. As already mentioned, this mixture has this C / N ratio after the mixing together of the fresh substrate and the recirculate in the mixing unit immediately before entry into the biogas reactor.

In addition, the device according to the invention can be realized in such a way that the control device is suitable for controlling the supply of the recirculation and / or the fresh substance. to control the mixing unit so that in the defined mixture, a C / N ratio of 20: 1 and a pH greater than 7, set. In particular, in the mixing process in the mixing unit, the aim is to produce fermentation substrate mixtures or defined mixtures in the mixing unit made of straw, low-viscosity liquid manure and animal excretions, which take place according to the requirements of biology taking into account the aforementioned framework conditions. These are, in particular, defined substrate mixtures of the fresh substrate and the recirculate having a pH of> 7 and a C / N ratio of 20: 1. The resulting defined mixture fulfills the criteria of biology because the formula or the controlled feed into the mixing unit gives the ratio of carbon to nitrogen of 20: 1 and has a pH value which is greater than 7. This creates an important building block for the framework conditions in the fermentation process. The biogas process according to the criteria of the pH value of greater than 7 and the C / N ratio of 20: 1 contains the milieu for an optimally occurring biocenosis in an anaerobic symbiosis. Here, methane bacteria determine the biogas process. Methane bacteria have antibiotic powers that greatly affect or even destroy in their dominated area all other microorganisms and even their own pathogenic germs in their viability.

Furthermore, the device according to the invention can be designed so that the fresh substrate before reaching the mixing unit has a dry matter content of 22% and 7 percent by weight straw, in particular straw chaff, and 93 percent by weight bovine slurry / solid manure or 15 percent by weight straw, in particular straw chaff, and 85 percent by weight percent pig manure / solid manure. In particular, the great potential of animal excrement, ie manure and solid manure, and straw to a fermentable substrate according to the requirements of a well-functioning biocenosis is thus used. The individual components of the finished fresh substrate are already clearly defined before they reach the mixing unit. The ready-mixed and prepared fresh substrate corresponds to the mixture prepared according to the recipe and is supplied volume-controlled via a closed eccentric screw pump of the mixing unit, wherein the fresh substrate before reaching the mixing unit preferably passes through the heat exchanger associated with the biogas plant. In the mixing unit, the recirculate is fed to the fresh substrate, so that the resulting mixture has a pH of greater than 7, preferably of 7.4. For example, the fresh substrate mixture comprises 7% by weight straw and 93% by weight bovine slurry / solid manure. A pig slurry fresh substrate preferably has a pH of 7.6 and preferably comprises 15% by weight straw and 85% by weight pig slurry / solid manure.

The mixing in the mixing unit always takes place according to the criteria of the pH and according to the requirements of the particularly advantageous C / N ratio of 20: 1 determined by tests. In this case, the point-precise ratio of the mixture in the mixing unit is, for example, in the

Fresh substrate achieved by the addition stream or the mixing of the recirculate into the mixing unit. Subsequently, the supply of the mixture takes place in the mixing unit in the biogas reactor. For the production of the finished fresh substrate, chaffs are preferably used, in particular renewable raw materials, primarily grain straw. However, any type of chaff, in particular plant straw, and manure can be used in the process according to the invention. be used. In particular, the following organic substances can be used to produce the ready-prepared fermentation substrate or fresh substrate: organic fertilizers such as liquid manure and solid manure, renewable raw materials such as maize silage, grass silage, cereal grains, organic sands of the processing agricultural industry, organic residues from municipalities and slaughter residues as well as green and grass cuts. However, particularly preferred is the use of animal excreta in the form of solid manure with the supply of liquid manure and straw chaff, so that these organic materials can be processed to a fermentable ready-prepared fermentation substrate or fresh substrate according to the requirements of a well-functioning biocoenosis, in particular mixed. The individual parts of the substrate are clearly defined. In particular, the targeted comminution of straw to straw chaff is advantageous to create the conditions for a fermentable substrate or fresh substrate. It is advantageous, in particular, that by means of the method according to the invention small agricultural enterprises can participate which supply solid manure and can receive chopped straw. In this context, it may be provided that the straw used is straw that is mixed with the manure and the solid manure in order to obtain the fresh substrate or the ready-prepared fermentation substrate mixture.

The inventive method for producing biogas from organic substances builds on the generic state of the art in that a supply of the recirculate and / or the fresh substrate to the mixing unit at least depending on a with a Frischsubstratzusammenset- is controlled to the size of the mixing unit supplied to the fresh substrate correlating size to obtain the defined mixture. This results in the explained in connection with the device according to the invention advantages in the same or similar manner, so reference is made to avoid repetition of the corresponding statements in connection with the device according to the invention.

The same applies mutatis mutandis to the following preferred embodiments of the method according to the invention, which is why reference is made in this regard to avoid repetition of the corresponding statements in connection with the device according to the invention.

The method according to the invention can be developed in an advantageous manner such that weight percentages of corresponding components of the fresh substrate are determined and on the basis of this determination the supply of the recirculate and / or the fresh substrate to the mixing unit is controlled.

Furthermore, the method according to the invention can be carried out such that the supply of the recirculate and / or the fresh substrate to the mixing unit is controlled in such a way that a C / N ratio of 20: 1 is established in the defined mixture.

In addition, the method according to the invention can be realized in such a way that the supply of the recirculate and / or the fresh substrate to the mixing unit is controlled such that in the defined mixture a C / N- Adjust ratio of 20: 1 and a pH greater than 7.

Furthermore, the method according to the invention can be configured so that the fresh substrate before it reaches the mixing unit is formed so that it has a dry matter content of 22% and 7% by weight straw, in particular straw chaff, and 93% by weight bovine slurry / solid manure or 15% by weight straw, in particular straw chaff, and 85% by weight of pig slurry / solid manure.

A preferred embodiment of the invention will be explained by way of example with reference to the figures.

Show it:

Figure 1 is a diagram showing the general course of natural fermentation;

Figure 2 is a schematic representation of an apparatus for producing a fresh substrate in one

Side view;

Figure 3 is a schematic representation of the device of Figure 2 in a plan view;

FIG. 4 a schematic representation of a further embodiment of the device for producing a fresh substrate in a plan view; Figure 5 is a schematic representation of another

Embodiment of the device for producing a fresh substrate in a side view;

Figure 6 is a schematic representation of the device of Figure 5 in a further side view;

Figure 7 is a schematic representation of the device of

Figure 5 in a plan view; and

Figure 8 is a schematic representation of the device according to the invention for the production of biogas, which is suitable for carrying out the method according to the invention.

FIG. 2 shows a schematic representation of a device 10 for producing a ready-made fermentation substrate or a fresh substrate in a side view. On the other hand, FIG. 3 shows a schematic representation of the device 10 of FIG. 2 in a plan view. The apparatus 10 for producing the finished fermentation substrate or the fresh substrate, which is subsequently fed to a biogas plant or biogas reactor explained later, in this case comprises a free-fall mixer 12 which is constructed in the manner of a concrete mixer with a rotatable drum (drum mixer). is trained. In particular, it is a stationary concrete mixer in the size classes of 6 m ³ to 15 m ³ nominal filling. Thus, the free-fall mixer comprises, in particular, the rotatable drum, shown only schematically, whose inlet and outlet openings can be pivoted. The drum can be pivoted in such a way into a feed and discharge position, that it the fermentation sub- strat over the inlet and outlet can be supplied. Furthermore, the drum can be pivoted into a mixing position, in which the actual mixing process explained in more detail below takes place. For this purpose, mostly obliquely positioned blades are mounted within the drum wall, which can lift in mixed positioning the supplied fermentation substrate, which then falls by gravity back down again. When the drum rotation direction is changed, the blades convey the fermentation substrate to the inlet and outlet openings and, together with the pivoting of the drum into the feed and discharge positions, the emptying of the drum is effected. The free-fall mixer 12 is further closable with a hydraulically sealing or fluid-tight flap, which is suitable for opening and closing the inlet and outlet opening of the drum. In addition, the free-fall mixer 12 is modified such that is connected by opening into the suction nozzle on the Vollverschlussklappe or the flap, a normally rotating vacuum pump.

Immediately at the inlet and outlet opening of the drum of the tumbler mixer 12, a transfer funnel 14 is arranged, into which a straw blower line 16 for feeding crushed straw (straw chop) and a Frischgüllezuführlei- device 18 for supplying fresh manure into the transfer funnel 14. Furthermore, a conveyor 20 is provided with a conveyor belt which terminates at one end portion at an upper edge of the transfer hopper 14 and extends with the other end portion in a hopper 22 for storage of solid manure. As a result of the conveyor 20 solid manure from the hopper 22 in the transfer hopper 14 can be conveyed. Furthermore, one is in the transfer container bottom or transfer container bottom opening discharge line provided over the means of an eccentric screw 24, the finished processed fermentation substrate or the fresh substrate in a heat exchanger of the later explained in more detail biogas plant can be discharged.

The method for producing the finished fermented substrate or the fresh substrate, which is supplied to a mixing unit of the biogas reactor explained in more detail below, on the basis of the device 10, is designed as follows. In the process, straw chaff and animal excreta in the form of solid manure, as well as liquid manure, are used to make the fermentation substrate in this case. However, other organic substances for mixing are also conceivable. First, shredded straw or straw chaff is blown into the free-fall mixer 12 via the straw blower line 16. In this case, the straw chop, for example, come from a straw shredder, not shown, with electric drive and be blown through a fan in the straw blower line 16, the

Straw chaff feeds the free fall mixer 12. In particular, round straw bales having a diameter of up to 1.5 m and / or square bales are used in the production of the straw chop and shredded such that the straw straw length is approximately 10 -25 mm, preferably 10 mm, 12 mm or 18 mm. The shredded material is thus blown directly from the straw shredder via the straw blower line 16 into the tumbler mixer 12, wherein almost simultaneously or shortly delayed an admission of fresh manure via the Frischgüllezu- supply line 18 and a promotion of solid manure on the

Conveyor 20 takes place. Subsequently, the free mixer is operated for mixing the organic substances in the drum and moved into its mixing position. This Feeding operation of the organic matters is controlled, for example, by a weighing device provided on the tumbler 12 and controlled so that a desired mixing ratio of manure / solid manure to straw chop can be adjusted. In this case, the determined weight fractions of the liquid manure, the solid manure and the straw chaff are stored, for example, in a memory, so that the exact composition of the fresh substrate, in particular the weight percent of the components of the fresh substrate, can be determined and retrieved at any time. In particular, a dosage of the individual substrate components, namely the filling of the drum of the free fall mixer with straw by weight and with liquid manure can be made by flow rate. In addition, the delivery of solid manure can also be adjusted via the conveyor 20. A corresponding emptying of the drum can be done via a speed control of the eccentric screw pump. Alternatively, however, a level measurement in the drum or in the transfer container can be made. In the tumble mixer 12, any desired fresh substrate mixture can be effectively produced, while at the same time ensuring that the supplied fresh manure is completely bound by the solids, such as solid manure and the straw chaff, and the air in the solids escapes. This is followed by a short mixing phase in which the liquid is completely bound by the solids. Subsequently, the flap of the drum is closed and there is a suction by means of a fluid technically coupled to the drum rotating Va- kuumpumpe. This initiates the anaerobic phase of the fresh fermentation substrate. Air in particular accumulates above the fresh fermentation substrate in the tumbler of the tumbler and is rotated with the normal rotation provided on the drum. sucked vacuum pump, so that the pressure prevailing in the drum atmospheric pressure of 1013.25 mbar is reduced by lOOmbar to 913mbar. The ready-mixed fresh substrate corresponds to the desired Frischgärsubstratmi- shear, the drum is opened via the flap, the direction of rotation of the drum is set to empty the drum and the Gärsubstratgemisch is flow controlled via the transfer funnel 14 of the eccentric screw pump 24 which supplies the desired Frischgärsubstratmischung in the later explained in detail biogas plant upstream heat exchanger promotes. The resulting treated fermentation substrate or fresh substrate then has a pH of 7.4 and consists of 7 percent by weight straw and 93 percent by weight manure / solid manure; Preferably, cattle slurry is used. Likewise, however, the fermentation substrate can also be made from pig manure, which has a pH of 7.6, the fresh substrate then consists of 15 percent by weight of straw and 85 percent by weight pig manure / solid manure. The fresh substrate mixture can also consist of several and different animal excretions as well as solid manure and

Straw exist. The mixing is always carried out according to the predetermined conditions of the pH and according to the specific desired C / N ratio, wherein at least the exact C / N ratio is then adjusted with the addition of a recirculate in a mixing unit of the biogas - explained in more detail later.

Figure 4 shows a schematic representation of a second embodiment of the apparatus for producing a Frischgärsubstrats in a plan view. In the description of this embodiment, only the differences from the first embodiment will be discussed below to avoid repetition. Be the first Embodiment identical or similar components with the same reference numerals. In this case, the apparatus 10 comprises two free-fall mixers 12, whereby a straw shredder 26 can supply straw chaffs to the two free-fall mixers 12 via a blower 28 and a straw blower line 16. In this case, a branch is provided in the straw blower line 16, in which the straw blower line 16 branches off to the two free-fall mixers 12. In particular, a fluidic switch is provided at the junction, via which the supply of the straw chaff to the two free-fall mixers can be adjusted. In addition, a Frischgüllezuführleitung 18 is provided, which also has a branch analogous to the straw blower line 16, at which the Frischgüllezuführleitung 18 branches to the two free-fall mixers 12, whereby both free fall mixer 12 can be acted upon with liquid manure. Furthermore, a discharge chute or a filling device 14 is provided in analogy to the transfer container 14 of the first embodiment, via which the fresh fermentation substrate mixture can be fed from the free-fall mixers 12 of an eccentric screw pump 24, around the Frischgärsubstratmischung via a line 30 the heat exchanger later supply more detailed biogas plant.

In the second embodiment, the method can be carried out analogously to the first embodiment, with the difference that two free-fall mixers have to be filled and emptied in order to achieve the finished fermentation substrate mixture or the fresh substrate in the desired amount of fermentation substrate.

Figure 5 shows a schematic representation of a third embodiment of the apparatus 100 for producing a finished fermented substrate or a fresh substrate in a side view. Furthermore, FIG. 6 shows a schematic representation of the device 100 of FIG. 5 in a further side view, while FIG. 7 shows a schematic representation of the device 100 of FIG. 5 in a plan view. In this embodiment, the apparatus 100 comprises at least one vertical mixer 112 known from the prior art, in particular two vertical mixers 112 with, for example, two mixing screws or vertical mixing screws 136, however, wherein the vertical mixers 112 are modified in a specific way, as exemplified below one of the vertical mixer 112 is explained. The vertical mixer 112 comprises a container 138 and a modified lid 134 pivotally mounted thereto with two vent openings 133 and a suction port 132 to which, for example, a vacuum pump, not shown, may be connected to provide vacuum in the vertical mixer 112, particularly in the container 138 to be able to produce, in particular at 913mbar. The suction port 132 and the vacuum pump at least partially form a suction device. Furthermore, a jacket heating is provided on the vertical mixer 112 for heating the Gärsubstratgemischs in the container 138 of the vertical mixer 112. In addition, the apparatus 100 comprises a straw shredder 126 with a fan, via which straw chaff can be fed via a straw blower line 116 to the vertical mixer 112 or to both vertical mixers 112. In particular, the straw chop is fed via the straw blower line 116 at an upper edge of the container 138 which partially forms the vertical mixer 112 and which can be closed via the lid 134. Furthermore, a slurry supply line 118 is provided, via the fresh liquid manure to the container 138 of the vertical mixer 112, likewise at the top. edge of the container can be fed. A seal between the lid 134 and the container 138 is made with appropriate seals.

The jacket heating is arranged on the outer jacket of the container 138 and is formed by heating pipes for low-temperature heating, which are protected by insulation. In addition to the suction opening 132, the above-mentioned vent openings 133 for venting the container 138 are provided in the lid 134 of the vertical mixer 112, which can be opened and closed via a valve by means of a ball valve and are opened, in particular, when blowing in straw chop. Furthermore, the container 138 of the vertical mixer 112 is coupled to a screw conveyor, in particular a transverse screw conveyor 124, via which the fermentation substrate mixture from the container 138 can be supplied to a further fermenting substrate mixer of a biogas plant which is not further of interest by means of longitudinal screw conveyors 140 provided in the container 138. The vertical mixer 112, the transverse screw conveyor 124 and the mixing unit, which will be explained in more detail later, are preferably located in an air-conditioned space with appropriate supply and exhaust air. The device 100 is emission-free, as the extracted air is passed through the suction port 132 via a filter that prevents both odor and particulate matter emissions. The two vertical mixers 112 are equipped with a programmable weighing device (not shown). The device 100 is adapted in terms of their plant size to the respectively required in the fermentation process Gärsubstratmengen and may for example comprise contents of 12 m ³ to 60 m ³ and larger. The process for producing fresh fermentation substrates, in particular straw chaff, manure and animal excreta in the form of solid manure, is as follows. First, the straw shredder 126 is operated via an electric drive, so that the container 138 of the vertical mixer

112 of the straw chop is supplied via the straw blower line 116. The straw chop is produced in particular from round bales and / or square bales with a diameter of up to 1.5 m or a corresponding edge length. A shred length of shredded straw chopped straw is between 5mm and 25mm, more preferably 10mm, 12mm, 18mm. The straw chop is thus directly from the straw shredder 126 into the container 138 of the vertical mixer 112, which may be formed in particular as a large-capacity container, blown and charged with thin liquid fresh manure on the Frischgüllezuführleitung 118. Furthermore, solid manure is fed via a conveyor, not shown, supplied during the supply of the fresh manure and the straw chaff and the vertical mixer 112 is operated briefly. The feeding process is controlled by a weighing device and controlled so that a mixing ratio of manure / solid manure to straw 62% to 7.3% (in percent by weight). Due to the fact that the manure / solid manure / straw mixture has an approximate dry matter content of 41.5%, it is not yet pumpable.

This mixture is referred to below as a mixture of the treatment stage I or quality grade I. Subsequently, a ventilation of the container 138 is carried out with further operation of the vertical mixer 112 for mixing, so that a rotting of the mixture of the treatment stage I can take place aerobically. This inevitably sets a self-heating phase in motion. This begins within a few hours of Mixing stage I and can reach a temperature of 40 ⁰ C and more in one day. The temperature in the mixture of the treatment stage I is detected for example via a temperature sensor, wherein upon reaching 35 ⁰ C, a further increase in temperature is prevented by further supply of fresh manure, while at the same time the vertical mixer 112 is operated. The added fresh manure is precisely defined and reduces the dry matter content to 31%. This mixture is referred to below as a mixture of the treatment stage II or the quality level II. By further short mixing cycles in the vertical mixer 112, the mixture of the treatment stage II is well aerated, after a rest period of about 4 to 6 hours, a new self-heating phase begins. Upon reaching a mixture temperature of 35 ⁰ C, another mixture heating is prevented again by re-feeding of fresh manure. The redefined feeding of the fresh manure results in a dry matter content of about 22%. Furthermore, the operation of the vertical mixer 112 for mixing the Gärsubstratge- mix takes place. The resulting mixture is hereinafter referred to as a mixture of the treatment stage III or quality grade III. The mixture of the processing stage III is achieved in about 5 days, at the latest after reaching 35 ⁰ C. Now, a closure of the container 138 by means of the lid 134 and a suction of the oxygen from the vertical mixer 112, in particular from the container 138, so that anaerobic conditions in the vertical mixer 112, in particular in the container 138, arise. After a predetermined period of time, the longitudinal conveyor screws 140 and a transverse conveyor screw of the transverse screw conveyor 124 are operated in order to produce the finished, ready-to-serve conveyor. te fermentation substrate or the fresh substrate of the later explained in more detail biogas plant supply.

In an alternative embodiment, it is provided that the Frischgärsubstratgemisch is produced by alternately supplying straw chaff and slurry and solid manure in a container quasi "in layers" and can be dispensed with mixing by means of blades as in the free fall mixer and by means of the mixing screw as in the vertical mixer , Otherwise, the third can be

Embodiment of Figures 5 to 7 transmitted analogously to this alternative embodiment.

Figure 8 shows a schematic representation of the inventive device for the production of biogas. The apparatus for producing biogas is, for example, as explained in more detail below, the fresh substrate prepared by the devices of Figures 2 to 7 or the finished processed fermentation substrate fed.

In this preferred embodiment, the biogas reactor 210 includes an outer container 212, which is preferably tapered in a central portion and cylindrically tapered in an upper portion 214 and in a lower portion 216 each toward the end. Inside the outer container 212, an inner container 218 is accommodated, which is cup-shaped and is arranged substantially at a constant distance from the outer container 212, so that between the outer container 212 and the inner container 218, a filling chamber 220 is formed, which envelops the inner container 218. The outer container 212 and the inner container 218 are preferably made of steel, but is also a version with other materials such as plastic feasible. An upper edge of the inner container 218, which in the present exemplary embodiment acts as an overflow edge 222, has been guided so far into the upwardly tapering upper section 214 that the cross-sectional area of the intermediate filling chamber 220 narrows upwards by about 50%. In the lower area of the inner container 218 is similar to the outer container 212 tapers down. The inner container 218 is preferably cylindrical and tapered in the tapered lower portion 224. Inside the inner container 218, a cylindrical inner tube 226 is arranged so that substantially the same distance is formed between the inner tube 226 and the inner container 218 as between the inner container 218 and the outer container 212. The lower edge of the inner tube 226 extends almost as far down as The inner edge of the inner tube 226 extends further upwardly than the overflow edge 222. Inside the inner tube 226 is a return tube 228, which is located in the interior of the inner tube 226 down in the Section 224 of the inner container 218 extends where the return tube 228 exits from the inner container 218. The return tube 228 extends upwardly so that the upper edge of the return tube 228 is placed below the overflow edge 222 with respect to the vertical. Advantageously, the upper edge of the return tube 228 extends substantially as far as the central (preferably cylindrical) portion of the outer container 212. In the present embodiment, the outer container 212, the inner container 218, the inner tube 226 and the return tube 228 are concentric arranged. Between the outside of the inner tube 226 and the inner side of the inner container 218, a first, substantially cylindrical, Mige intermediate chamber 230 is formed. Between the outside of the return pipe 228 and the inside of the inner tube 226, a second, substantially cylindrical intermediate chamber 232 is formed. The first intermediate chamber 230 and the second intermediate chamber 232 communicate with each other in the lower area. The upper edge of the return pipe 228 forms a filling opening 234. Inside the return pipe 228, a return passage 236 is formed. As already mentioned, the return pipe 228 leads out of the inner container 218 in the lower portion 224 of the inner container 218, passes through the wall of the outer container 212 in the lower portion 216 and leads into a vaccum pump 238, which is preferably an eccentric screw pump. At the portion of the return pipe 228, which extends within the filling chamber 220, a drain pipe 240 branches off, which extends so far in the filling chamber 220 that an upper opening of the drain pipe 240 at about the same height as the filling opening 234 of the return pipe 228 is located. The drain pipe 240 is designed in the upper area so that the upper portion of the

Tube is bent over more than 90 degrees and the bent portion extends through the wall of the outer container 212 to the outside. The drainage channel 242 formed by the drainage pipe 240 is thus U-shaped connected to the return passage 236, so that the return passage 236 and the drainage passage 242 form a communicating pipe. The filling chamber 220 is designed so that it can be filled in a lower region from the outside with organic substances or an organic substance. The organic substance is conveyed in a manner explained in more detail later also through the filling chamber 220, the first intermediate chamber 230 and the second intermediate chamber 232, wherein the organic substance still contains sediments or heavy materials. sen can. Therefore, at the lowest end of the outer container 212 and the inner container 218, a pipe piece 244 and 246 respectively branches off, which is provided near the respective container with a slide 248, 252 and at a certain distance to a further slide 250, 254 is provided , With the respective sliders, the respective pipe section 244, 246 can be selectively opened and closed. The distance of the slider 250 from the slider 248 is preferably about 80 cm and the distance of the slider 252 to the slider 254 is preferably 60 cm. In normal operation, the sliders 248 and 252 are opened and the sliders 250 and 254 are closed. If sediments located in the organic substrate thus settle downwards, they slide along the sections 216 and 224 to the center of the respective container 212, 218 and leave it through the respective open slide 248, 252 into the respective pipe section 244, 246 the sediments are accumulated on the closed slides 250, 254. The pipe section between the slide 248 and 250 and the pipe section between the slide 252 and 254 thus each form a collecting space 256, 258 for sediments. Preferably, the pipe sections at the collecting spaces 256, 258 are transparent, for example by means of Plexiglas, so that the amount of accumulated sediment can be monitored. Upon reaching a certain amount, the accumulated sediments may be emptied by closing the respective gates 248 and 252 to prevent leakage of the containers 212, 218. Then, the respective slides 250 and 254 are opened and the collecting spaces 256, 258 are emptied. For normal operation, the slides 250 and 254 are closed again and the slides 248 and 252 are opened. Preferably, by not shown in Figure 8 connection of the plenum 258 and the filling chamber 220, for example by means of a bypass, a circuit can be formed. In particular, a pump may be provided in the bypass, so that at least temporarily a cycle of the organic substances between the filling chamber 220 and the intermediate chamber 230 is produced during operation of the pump. As a result, in particular at least in the intermediate chamber 230 resulting floating layers can be discharged via the collecting space 258 and the filling chamber 220 perform.

An isolation 260 shown only in sections surrounds the outer container 212 completely (the supply and discharge lines are recessed), so that the advantageous for the production of biogas temperature of preferably 35 ⁰ C inside the biogas reactor 210 can be kept as constant as possible and thus less energy must be supplied to maintain this temperature. In the insulation 260, a heater 262 is embedded, which is formed in the preferred embodiment in the form of spirally arranged water pipes, which lead water, which is heated, for example, in a cogeneration unit, not shown. Alternatively, heating wires may also be embedded in the insulation 260. The heater 262 preferably surrounds the outer container 212 from below to below the upper portion 214. To protect the insulation 260, the insulation 260 together with the heater 262 may be surrounded by a protective jacket, such as a metal jacket. At the upper end of the outer container 212, this is the curved end of the upper portion 214, a gas discharge line 264 is branched off. This Gasabführleitung 264 is guided outside the outer container 212 adjacent to this, wherein an end portion of the gas discharge line 264 in enters a liquid container 266 and extends downwardly within this liquid container 266. The liquid container 266 is preferably a cylindrical container whose lower portion tapers conically downward. At the top of the liquid container 266, a gas feed line 268 is branched off, via which the biogas obtained is fed to a gas storage, not shown, from which it is available to a cogeneration plant, not shown, for generating electricity. At the lower end of the liquid container 266, a pipe piece 270 is led out of the liquid container 266. From this pipe section 270 branches off a riser 272, which is guided in addition to the liquid container 266 to the upper edge of the liquid container 266 upwards. The riser 272 is open at the top and between the top of the

Riser tube 272 and more than 1 m below the upper edge are formed three openings 274, wherein the bottom of the openings is more than 1 m below the upper edge of the riser 272. The distance between the bottom of the three openings 274 and the top of the three openings 274 is preferably 1 m. The riser 272 is connected to the interior of the liquid container 266 in accordance with the principle of communicating tubes. During operation, the interior of the liquid container 266 is filled with a liquid 276, preferably water, whose liquid level can be adjusted by means of the openings 274. By virtue of the principle of communicating tubes, riser 272 has the same liquid level as liquid container 266, so that if the bottom of orifices 274 are opened, liquid container 266 can be filled to a liquid level 276 which is the level of the bottommost of the orifices 274 corresponds. If the bottom of the openings 274 closed, for example by means of a plug, the liquid container 266 can be filled with a higher liquid level, which corresponds to a level of the uppermost openings 274. If all openings 274 are closed, the liquid container 266 can be completely filled, wherein upon reaching the complete filling, the liquid reaches to the upper edge of the riser 272. The end 278 of the gas discharge line 264 leading out of the outer container 212 is arranged inside the liquid container 266 such that this end 278 is immersed in the liquid 276. The lower opening of the end 278 is spaced 2 m from the top of the openings 274 of the riser 272. The immersion depth of the gas discharge line 264 into the liquid 276 is thus minimally 1 m when the bottom of the three openings 274 is opened, and a maximum of 2 m when only the top of the three openings 274 is opened. By this adjustable immersion depth of the end 278 of the gas discharge line 264, the pressure within the outer container 212 can be adjusted to a constant pressure. When filled with water, a pressure of 0.1 bar in the outer container 212 is thus achieved with an immersion depth of 1 m. At an immersion depth of 2 m, a pressure of 0.2 bar is set in the outer container 212. At the lower end of the liquid container 266, the pipe piece 270 is led out as described above. It is in the

Pipe section between the outlet on the liquid container 266 and the branch of the riser 272 a slide 280 and in the pipe section after the branching of the riser 272 a slide 282 is provided. With these two slides 280, 282, the flow through the pipe section 270 can be selectively opened or closed, in normal operation, the slide 280 is opened and the slide 282 is closed, whereby a collecting space 284 for sediments is excluded. is formed. Thus, impurities contained in the biogas are filtered out by the liquid 276. The gas rises in the liquid 276 and the filtered out sediments settle down in the liquid 276, where they are guided by the tapered shape of the lower portion of the liquid container 266 to the center and collect in the plenum 284. In the region of this plenum 284, the pipe section 270 can be made transparent, for example by means of Plexiglas, so that the accumulation of sediments can be monitored. When the accumulation of sediment in the collection space 284 has reached a certain amount, the slide 280 can be closed and the slide 282 can be opened, so that at the lower end of the tube 270 the sediments can be emptied out of the system. After emptying the collecting chamber 284, the slide 282 is closed and the slide 280 is opened again.

As mentioned above, the filling chamber 220 can be filled from below. For this purpose, a pipe section which connects the filling chamber 220 to the outlet of a mixing unit 286 extends through the wall of the outer container 212 in the lower section 216. The output of the mixing unit 286 tapers towards the filling chamber 220, preferably by 50%. The inputs of the mixing unit 286 are connected to pipes by means of which the mixing unit 286 is connected to the outputs of the seed pump 238 and a heat exchanger 288. The mixing unit 286 mixes organic substances supplied from the seed pump 238 (the recirculate) and from the heat exchanger 288 (the fresh substrate), preferably in a predefined ratio that correlates at least with a fresh substrate supplied to a fresh substrate composition of the mixing unit Size depends. The heat exchanger 288 has a temperature sensor 290, which is arranged near its exit and with which the temperature of the organic substrate or the fresh substrate located in the heat exchanger can be determined. The heat exchanger 288 is connected on the input side to a fresh-substrate pump, which is preferably the eccentric screw pump explained above in connection with the device of FIGS. 2 to 7.

Between heat exchanger 288 and mixing unit 286, between mixing unit 286 and outer container 212, between vaccum pump 238 and outer container 212 and between outer container 212 and liquid container 266, a slide 292 is arranged in each case, with which the respective pipe connections can be selectively opened and closed. In normal operation, all these slides 292 are opened, but it may be necessary, for example, maintenance that when replacing a component, the respective component of the component upstream and / or downstream slide 292 are closed to allow replacement of the component, without organic matter exit the system.

The operation of the apparatus for producing biogas from FIG. 8 or a method for producing biogas using the apparatus from FIG. 8 will be described below. In prior art methods, too little attention has been paid to the fact that the two types of methane bacteria of the facultative methane bacteria and the obligate methane bacteria live in symbiosis, ie they complement each other and are interdependent. The first phase described above (hydrolysis or acid generator phase) and the second phase (methanation phase) of the fermentation process run time-delayed by about six hours, during which the so-called hydrolysis phase takes place during the first six hours. The prepared alcohols and fatty acids must also be able to be processed in the subsequent second phase. For this it is essential that no disturbances caused by stirring or mixing as in the inventive method by a renewed, excessive acidification bring the first phase out of balance. Each addition of fresh substrate activates the formation of acid, leading to the accumulation of acid products, if the treatment of organic substances does not function optimally, the actual fermentation process succumbs to the overproduction of acid products. Therefore, in the present process, the acid generator phase (hydrolysis) has deliberately come to the forefront, making the present process different from many prior art processes. In the present process, hydrolysis and methanation are in equilibrium and are not carried out separately as in prior art processes. If one were to carry out the hydrolysis and methanation separately, one would have to introduce a pre-acidified substrate into the active process, which would result in acid concentrations forming and the process would take a long time for equilibrium production, sometimes 20 to 30 days and more. The same drawback arises from stirring and mixing as well as blowing gas. In the present process is deliberately dispensed with disturbances of this balance by stirring and mixing.

The fresh-substrate pump is controlled by means of a control, not shown, and pumps the fresh substrate into the heat exchanger 288 and from there into the mixing unit 286 and finally into the filling chamber 220 of the Biogas reactor 210. Then the fresh-substrate pump shuts off. The supplied into the heat exchanger 288 fresh substrate is heated, in the present embodiment to 37 ⁰ C, which is monitored by means of the temperature sensor 90. This heating is achieved, for example, by introducing a hot fluid into the heat exchanger 288, wherein the fluid is spatially separated from the fresh substrate. This fluid preferably has collected C. As soon as the temperature sensor 290, a temperature of approximately 80 ^0, that the temperature ranges from 37 ° C ER, the fresh substrate pump is turned on, so that a new fresh substrate is introduced into the heat exchanger 288 and the preheated Fresh substrate exiting the heat exchanger 288 and enters the mixing unit 286. With the fresh-substrate pump, the vaccination pump 238 is also operated at the same time, which will be explained in more detail later. The fresh-substrate pump preferably remains switched on until the temperature sensor 290 detects a temperature equal to or less than 35 ^° C. The fresh-substrate pump is then switched off so that the fresh organic substrate, which has not yet been preheated in the heat exchanger 288, can now be preheated until it reaches a temperature of 37 ^° C. and is transported on as described above. The intervals at which the organic fresh substrate is supplied may be made variable, and the fresh-substrate pump is preferably controlled not only depending on the temperature sensor 290, but also depending on the fresh-substrate composition. The same applies to the vaccum pump 238. Rather, the control by means of temperature sensor 290 is to be understood such that a basic prerequisite for the supply of the fresh substrate is that it has a minimum temperature of 35 ^° C. The intervals may also be longer, as for the preheating of the fresh substrate. strats in the heat exchanger 288 required. Thus, with rapid preheating of the fresh substrate in the heat exchanger 288, a nearly continuous supply or a supply of fresh substrate in certain cycles can take place. The vaccine pump 238 serves to feed from the biogas reactor 210 discharged substrate, namely the so-called recirculate, which also has a temperature of 35 ⁰ C, in the mixing unit 286. As mentioned above, the fresh-substrate pump and the vaccum pump 238 are operated synchronously. However, the fresh-substrate pump and the vaccum pump 238 are actuated by a control device, for example, such that a supply to the mixing unit 286 of the aforementioned recirculate and the fresh substrate, which is produced, for example, by the devices according to FIGS. 2 to 7, at least as a function of A variable correlating with a fresh substrate composition of the fresh substrate supplied to the mixing unit 286 is made to obtain a defined mixture in the mixing unit 286. In particular, the weight percent of corresponding components of the fresh substrate are determined by the control device, for example, the straw chaff, the liquid manure and the solid manure. Based on this determination, the supply of the recirculate and / or the fresh substrate to the mixing unit 286 is controlled. Specifically, the amount of the recirculated fluid supplied to the mixing unit 286 and the amount of the fresh substrate supplied to the mixing unit are controlled based on the detected composition of the fresh substrate. Preferably, the supply of the recirculate and the fresh substrate into the mixing unit 286 is controlled such that a C / N ratio of 20: 1 and a pH greater than 7 are established in the mixture in the mixing unit 286. For example, such a mixture may be subject to recirculated feed is achieved when the fresh substrate before reaching the mixing unit 286 has a dry matter content of 22% and 7% by weight straw, in particular straw chaff, and 93% by weight bovine slurry / solid manure or 15% by weight straw, in particular straw chaff, and 85% by weight pig slurry / Solid dung includes. Mixing the recirculate with fresh substrate in the right proportions activates the fermentation process so that the remaining organic substances are attacked and degraded. This measure contributes significantly to the high degradation rate of the organic matter of the present process, which can be over 70% and higher.

In the mixing unit 286, organic matter therein is further mixed by the conically tapered outlet of the mixing unit 286. At the end of a fermentation process most of the organic matter is degraded and the methane bacteria are present in highest concentration. By this inoculation of the methane bacteria in the fresh substrate by means of the mixing unit 286 ensures that the fermentation process begins very stormy, because the large number of bacteria meets a large mass of fresh substrate and thus causes the stormy beginning fermentation process. After entering the filling chamber 220 that rises

Substrate in the filling chamber 220, driven by subsequent substrate, upwards. The upwardly flowing in the filling chamber 220 substrate is compressed when reaching the constriction in the upper region of the filling chamber 220, so that no floating layers arise. The gas mass overflowing at the overflow edge 222 falls over the overflow edge 222 into the first intermediate chamber 230. In this fall over the overflow edge 222, the digestate completely degasses. constantly upwards. In addition, any aggregates of the substrate are broken. The biogas collects in the upper portion 214 of the outer container 212, as shown by dots in FIG. Since the upper edge of the inner tube 226 is higher than the overflow edge 222, it is avoided that the fermented mass moves directly from the filling chamber 220 into the second intermediate chamber 232. Rather, the filled in the first intermediate chamber 230 digestive mass moves down in this. This movement of the digestive mass downwards is driven by the refilled digestate. In the lower region of the inner container 218, the first intermediate chamber 230 is connected to the second intermediate chamber 232, so that the fermentation mass, which at the lower end emerges from the first intermediate chamber 230, enters the lower end of the second intermediate chamber 232. In this second intermediate chamber 232, the fermentation mass rises. Due to the principle of communicating vessels prevails in the first intermediate chamber 230 and in the second intermediate chamber 232, substantially the same level level. This filling level corresponds to the filling opening 234.

If the fermentation mass in the second intermediate chamber 232 reaches the filling opening 234, the fermented mass falls into the return duct 236 and sinks downwards in this. The height by which the substrate in the return channel 236 plunges downward depends sometimes on the pressure with which the interior of the biogas reactor 210 is acted upon. Even when falling from the second intermediate chamber 232 in the return channel 236, the biomass is completely degassed. Due to the fact that the drainage channel 242 forms a communicating tube with the return channel 236, the fill level level hangs in the drainage channel

242 from the level in the return channel 236 from. About half of the return channel 236 down moving substrate leaves the biogas reactor via the drainage channel 242 and the other half is conveyed by the vaccum pump 238 into the mixing unit 286 where it is mixed with the newly supplied fresh substrate as discussed above. Within the outer container 212, the biomass is held by the heater 262 at a temperature of about 35 ⁰ C. The present process takes place in the mesophilic range (30 ° C-38 ° C), because in this area the degradation rates are higher and thus a larger amount of gas can be generated. The methane bacteria present in the process are very sensitive and require as far as possible a constant temperature which is not subject to any great fluctuations.

The return channel 236 is reached after approximately 8 to 10 days, the substrate at this position only containing reactionless fermentation mass which is highly enriched with the predominant fermentation bacteria. The biogas accumulated in the upper section 214 of the outer container 212 is kept at a constant pressure by means of the liquid container 266 and is first continuously discharged via the gas discharge line 264 into the liquid container 266 and fed from there via the gas feed line 268 to a gas storage (not shown). In this case, no pressure valves are used which would easily wear, but the pressure is kept constant over the immersion depth of 1 m to 2 m. The promotion of the fermentation mass throughout the system by means of pump pressure of the pumps 238 and 292, by the hydrostatic gradient from the overflow edge 222 to the filling opening 234 and by the gas pressure in the upper portion 214 of 0.1 to 0.2 bar. About the static gradient and the internal pressure, the conveying effect for the organic substances in the biogas reactor can be varied, ie the static gradient and / or The internal pressure can be adjusted to the consistency of the organic matter.

As a result, a fermentation process is achieved in which organic components are reduced in a relatively short time, about 6 to 10 days, up to 70% and more. This means the extraction of a large amount of gas and, given the appropriate conditions, a very good economy. The conversion of the organic matter takes place in closed containers, so that no odors escape to the outside. The fermentation residues that emerge at the drainage pipe 240 have an earthy odor and are free from mucilage and environmentally friendly in all respects. These can be applied without further treatment as natural fertilizer on agricultural land. If further treatment is necessary for compelling reasons, then a solid-liquid separation is appropriate and possible with little effort, because the fermented residues can be easily separated.

As an alternative to the described embodiment, it is possible to omit the heat exchanger 288 in the apparatus for producing biogas shown in FIG. 8 and to preheat the fresh substrate by means of steam injection.

The features of the invention disclosed in the foregoing description, in the drawings and in the claims may be essential to the realization of the invention both individually and in any combination. LIST OF REFERENCE NUMBERS

10 device

12 free fall mixer

14 transfer containers or transfer funnels

16 straw blower line

18 Slurry feed line 20 Conveyor with conveyor belt

22 funnels for solid manure

24 eccentric screw pump

26 straw shredders

28 blower 30 line

32 drum flap with suction openings

100 device

112 vertical mixer

116 Straw blower line 118 Slurry feed line

124 screw conveyor (cross-auger conveyor)

126 straw shredders

132 suction opening

133 vents 134 Lid

136 vertical mixing screws

138 containers

140 longitudinal screw conveyors 210 biogas reactor 212 outer casing

214 Upper section of the outer housing

216 Lower section of the outer housing

218 inner housing 220 filling chamber 222 overflow edge

224 Bottom section of the inner container

226 inner tube 228 return tube

230 first intermediate chamber 232 second intermediate chamber 234 filling opening

236 Return channel 238 Vaccination pump

240 drainage pipe

242 drainage channel

244 pipe section

246 Pipe piece 248 slide

250 slides

252 sliders

254 sliders

256 collection room 258 collection room

260 isolation

262 heating

264 gas discharge line

266 Liquid tank 268 Gas inlet line

270 pipe section

272 riser

274 openings

276 Fluid 278 End of the gas discharge line

280 slides

282 sliders

284 collection room 286 mixing unit

288 heat exchangers

290 temperature sensor

292 pushers

Claims

1. A device for generating biogas from organic substances, comprising a at least one chamber (220, 230, 232) forming biogas reactor (210), via a mixing unit (286) having a defined mixture of a fresh organic material having organic substrate and an organic matter Rezirkulat is fed, characterized in that a control device is provided which is suitable, a supply of the recirculation and / or the fresh substrate to the mixing unit (286) at least in response to a correlating with a fresh substrate composition of the mixing unit (286) fresh substrate size control to obtain the defined mixture.

2. Device according to claim 1, characterized in that the control device is adapted to determine weight percent of corresponding components of the fresh substrate and on the basis of this determination, the supply of the recirculate and / or the fresh substrate to the mixing unit (286) to control.

3. Apparatus according to claim 1 or 2, characterized in that the control device is adapted to control the supply of the recirculation and / or the fresh substrate to the mixing unit (286) such that in the defined mixture a C / N ratio from 20: 1.

4. Device according to one of claims 1 to 3, characterized in that the control device is suitable, controlling the supply of the recirculate and / or the fresh substrate to the mixing unit (286) such that a C / N ratio of 20: 1 and a pH greater than 7 are established in the defined mixture.

5. Device according to one of claims 1 to 5, characterized in that the fresh substrate before reaching the mixing unit (286) has a dry matter content of 22% and 7 percent by weight straw, in particular straw hackle, and 93 percent by weight bovine slurry / solid manure or 15 percent by weight straw , in particular straw chaff, and 85% by weight pig slurry / solid manure.

6. A process for the production of biogas from organic substances by a biogas plant, the at least one

Chamber (220, 230, 232) forming biogas reactor (210) to which via a mixing unit (286) a defined mixture of an organic material fresh substrate and an organic recirculating material is supplied, characterized in that a supply of the recirculated and / or the fresh substrate is controlled to the mixing unit (286) at least in response to a size correlating with a fresh substrate composition of the fresh substrate supplied to the mixing unit (286) to obtain the defined mixture.

7. The method according to claim 6, characterized in that weight percent of corresponding components of the fresh substrate are determined and on the basis of this determination, the supply of the recirculate and / or the fresh substrate to the mixing unit (286) is controlled.

8. The method according to claim 6 or 7, characterized in that the supply of the recirculate and / or the fresh substrate to the mixing unit (286) is controlled such that adjusts a C / N ratio of 20: 1 in the defined mixture.

9. The method according to any one of claims 6 to 8, characterized in that the supply of the recirculate and / or the fresh substrate to the mixing unit (286) is controlled such that in the defined mixture, a C / N-

Adjust ratio of 20: 1 and a pH greater than 7.

10. The method according to any one of claims 6 to 10, characterized in that the fresh substrate before reaching the

Mixing unit (286) is formed so that it has a dry matter content of 22% and 7 weight percent straw, especially straw chaff and 93 weight percent bovine slurry / solid manure or 15 weight percent straw, in particular straw chaff, and 85 weight percent pig slurry / solid manure.