WO2009068005A2 - Method and apparatus for the production of a fully processed fermentation substrate used for producing biogas - Google Patents

Abstract

The invention relates to a method for producing a fully processed fermentation substrate which is especially used for producing biogas in a biogas plant. In said method, in order to process the fermentation substrate, organic matter is mixed by means of a mixing device (12; 112) such that a fermentation substrate mixture is obtained. According to the invention, the fermentation substrate mixture is at least temporarily placed in a room in which a negative pressure relative to an atmospheric pressure is generated before the mixture reaches the biogas plant such that the fully processed fermentation substrate is obtained. The invention further relates to a corresponding apparatus for producing a fully processed fermentation substrate as well as a system comprising a biogas plant.

Description

Method and device for producing a ready-prepared fermentation substrate for biogas production

The invention relates to a method for producing a ready-prepared fermentation substrate, which is provided in particular for biogas production in a biogas plant, in which for the treatment of the fermentation substrate organic substances are mixed by a mixing device to obtain a fermentation substrate mixture.

Furthermore, the invention relates to an apparatus for producing a ready-prepared fermentation substrate, which is provided in particular for biogas production in a biogas plant, with a mixing device which is suitable for the treatment of the fermentation substrate to mix organic substances to obtain a fermentation substrate mixture. Moreover, the invention relates to a system with a biogas plant.

Usually, it is necessary to treat so-called fermentation substrates accordingly, in order then to supply these processed fermentation substrates to a biogas plant or a biogas reactor for the production of biogas. In the biogas plant, in particular in a reactor room of

Biogas plant, then usually takes place in several mutually coupled chambers of the reactor chamber, the generation of biogas. 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 is usually coupled to the filling chamber of the reactor space, wherein a heat exchanger of the biogas plant between the filling chamber and the apparatus for producing the finished fermentation substrate may be arranged to obtain a suitable temperature of the finished fermentation substrate for the production of biogas in the reactor space.

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 are found everywhere in nature, e.g. 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 residual substances from industry, gastronomy, trade, agriculture (manure and solid manure) or renewable raw materials (maize silage, 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 take over the conversion into

Alcohols, fatty acids and their salts to gas. This second phase is called the methanation phase. The first and second phases are delayed by about six hours. in which the so-called hydrolysis phase takes place during the first six hours.

Biogas plants have the goal of creating an environment for organic fermentation, which enables this organic fermentation to be 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 ready-prepared fermentation substrate (fermented mass), hereinafter referred to as substrate, is of particular importance in order to favor the anaerobic processes in the biogas plants. In other words, the composition of the biogas plant must be taken into account in order to achieve the desired anaerobic processes in the biogas plants. It is generally known that a balanced ratio of carbon and nitrogen (C / N ratio) must 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 falls below or exceeded these C / N ratios Inhibitions with regard to a bacterial culture are likely to occur. Since all organic substances comprise at least three basic building materials, namely carbohydrates, fats and proteins, the two chemical elements carbon C and nitrogen N are in each case also present in the substrate or the fermentation mass. However, it is extremely troublesome to estimate the amounts of carbon C and nitrogen N of the individual organic masses in the substrates, and consequently also an exact mixing of the individual organic masses of the substrate to achieve a certain precise composition of the substrate is extremely difficult. 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 only available after a long period of time, usually after about 3 weeks, during which the substrate may already have 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 devices belonging to the state of the art for producing the ready-prepared fermentation substrate in that the finished fermentation substrate is not prepared in particular for the anaerobic fermentation process in the biogas plant. What has a lasting effect on the anaerobic symbiosis in the reactor space of the biogas plant.

It is therefore an object of the invention to develop the generic methods and devices such that the aforementioned disadvantages can be at least partially overcome, and in particular that on the basis of substrate production, the fermentation processes are favored in the biogas plants.

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

Advantageous embodiments and further developments of the invention düng result from the dependent claims.

The inventive method for producing a ready-prepared fermentation substrate is based on the generic state of the art in that the fermentation substrate mixture is at least temporarily arranged before reaching the biogas plant in a room in which with respect to an atmospheric pressure, a negative pressure is generated to the finished processed fermentation substrate receive. By the method according to the invention thus ready prepared fermentation substrates can be prepared which are already particularly for an anaerobic

Symbiosis in a reactor room biogas plant are suitable. Because by the generation of the negative pressure already in the device according to the invention is achieved, as little as possible oxygen or air in the fermentation process in the biogas plant or to get the reactor space of the biogas plant. The anaerobic symbiosis develops better in the biogas plant and the prerequisites for this are thus at least approximately already with entry into the biogas plant reactor room. With the method according to the invention, any required ready-prepared fermentation substrate can be produced. In this case, for example, pig manure, chicken manure or other organic waste materials can be used. Crucial in this context is the formulation of the fermentation substrate, which is prepared in the inventive method from the fermentation substrate mixture. By generating the negative pressure conditions are created before reaching the biogas plant, so that the biocenosis can take place suitable for the conditions of anaerobic symbiosis. There is thus a preferred environment for the bacteria.

The method according to the invention can be advantageously developed in such a way that the negative pressure is generated in the mixing device, in which the fermentation substrate mixture is arranged. In particular, it is advantageous to carry out the generation of the negative pressure in the mixing device. It requires only minor modifications of

Mixing device to make a corresponding vacuum generation can. In the case of a free-fall mixer, only one flap is provided for fluid-tight closing of a drum. In this case, a suction device with a vacuum pump is preferably provided on this flap, via which a drum interior via holes in the flap can be withdrawn air. In the case of a vertical mixer, the flap may be modified to close a container of the vertical mixer in a fluid-tight manner in the same way as in the case of the free-fall mixer.

Furthermore, the process according to the invention can be carried out in such a way that chaff, manure, in particular, are used as organic substances. slurry and solid manure, which are mixed by the mixing device to the fermentation substrate mixture. The energy potential from animal excrement in the form of manure and solid manure can also be used, so that it is not necessary to ferment food in biogas plants. Solid manure, especially manure, is a mixture of manure and litter with more or less admixture of urine. In the context of the process according to the invention, it is particularly preferred to use chaff, in particular renewable raw materials, primarily grain straw. However, any type of chaff, especially plant straw, and manure may be used in the method of the invention. In particular, the following organic substances can be used to produce the finished fermentation substrate: manure, such as liquid manure and solid manure, renewable raw materials such as corn silage, grass silage, cereal grains, organic seeds of the processing agricultural industry, organic residues from municipalities and slaughter residues, and green waste. and lawn cuts. However, the most preferred is the

Use of animal excreta in the form of solid manure with supply of low-viscosity manure and straw chaff, so that these organic substances can be prepared to a fermentable ready-prepared fermentation substrate according to the requirements of a well-functioning biocoenosis, especially 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. It is particularly advantageous that the inventive

Procedures may involve small farms that can deliver solid manure and receive shredded straw. In this connection, the method according to the invention can be realized such that plant straw is used as chaff, which is mixed with the manure and the solid manure by the mixing device to the fermentation substrate mixture.

The process according to the invention is particularly preferably implemented in such a way that the mixing of the organic substances is carried out by means of a free-fall mixer as mixing device. The use of the tumbler mixer is an almost optimal solution. In this tumbler mixer, any desired fermentation substrate mix can be effectively produced; At the same time, it ensures that the liquid supplied in the form of liquid manure is completely bound by solids of the fermentation substrate, such as the solid manure and the straw chaff, and that the air in the solids escapes. The air collects in the closed drum of the tumbler, the pressure inside the drum is reduced by a normally rotating vacuum pump to 913 mbar, which is preferably attached to the flap or the lid of the tumbler. The ready-mixed and ready-prepared fermentation substrate corresponds to the mixture prepared according to the recipe and is preferably supplied volume-controlled to a closed eccentric screw pump, which conveys the recipe-prepared and ready-prepared fermentation substrate into, for example, a biogas plant upstream heat exchanger. The resulting substrate preferably has a pH of 7.4 and preferably comprises 7% by weight of straw and 93% by weight of bovine manure. However, a pig slurry digestate of pH 7.6 may also be produced which comprises 15% by weight of straw and 85% by weight of pig manure. The fermentation substrate mixture may further consist of several and different animal excrements, in particular solid manure, and straw. The mixing always takes place according to at least the criteria of the pH value and at least according to certain requirements of the C / N ratio.

Alternatively, the method according to the invention can also be designed such that the mixing of the organic substances is performed by a vertical mixer as a mixing device.

Furthermore, the method according to the invention can also be developed in such a way that the mixing of the organic substances by the free fall mixer takes place under a single slurry feed. This represents a significant advantage over other mixers for mixing fermentation substrate mixtures, because due to the nature of the free fall mixer is only once liquid manure to supply the organic substances that can be almost completely absorbed by the free fall mixer in solids of organic matter.

Alternatively, it may be provided to further develop the method according to the invention in such a way that the mixing of the organic substances takes place by means of the vertical mixer under repeated, temporally spaced liquid manure feed. In particular, it is then preferred to carry out the method according to the invention on the basis of straw chaff, animal excrements such as solid manure, and low-viscosity manure. For example, straw chopper made of round straw bales and / or square bales is initially accompanied by a straw shredder with electric drive a diameter up to 1.5 m or produced with appropriate edge length. In this case, a chop length of 10mm, 12mm or 18 mm is particularly preferred, but this is not necessarily required. The straw chop is then blown directly from the straw shredder into the vertical mixer and charged with low-viscosity liquid manure. This process is controlled by means of a weighing device provided on the vertical mixer and controlled so that a mixing ratio of manure / solid manure to straw is 62% to 7.3% (data in percent by weight).

The resulting manure / solid manure / straw chaff mixture then has a dry matter content of about 41.5% and is not yet pumpable. This solid mixture is referred to in this description as a mixture of the treatment stage I or quality grade I. It then enters a rotting, which takes place aerobically, which inevitably results in a self-heating phase. This begins after a few hours from the generation of the mixture of the treatment stage I and can reach in one day a temperature of 40 ⁰ C and more. The temperature in the

Mixture, in particular in solids of the mixture is detected for example via a temperature sensor, so that when reaching 35 ⁰ C, a renewed supply of low-viscosity fresh liquid manure is made. The re-supplied thin liquid fresh manure is well defined and reduces the dry matter content of the fermentation substrate mixture to 31%. This fermentation substrate mixture, which in particular is still partly a solid mixture, is referred to in this description as a mixture of the preparation stage II or the quality grade II. By short

Mixing cycles, the fermentation substrate mixture is well aerated and begins in the resting phase after about 4 to 6 hours a new heat phase. When reaching 35 ⁰ C, this will also Heating stopped by re-adding fresh manure. The fermentation substrate now reaches a dry matter content of 22%. The well-mixed fermentation substrate in the vertical mixer is referred to in this description as a mixture of the treatment stage III or quality level III. The mixture of quality grade III is completed on the 5th day, at the latest after reaching 35 ^° C. This substrate preparation in three quality levels or in three steps is required for technical reasons which have resulted from tests and are particularly effective for producing a suitable fermentation substrate , Because the mixture via the vertical mixer is suitable only feasible if the supplied amount of liquid or liquid manure is also completely bound by the solids in the fermentation substrate mixture, ie of solid manure and straw. Vertical mixers are usually suitable only for solids. The mixing in of liquids is only possible step by step and only works in several steps. If too much liquid is added, the result is that the liquid would seep to the bottom and would be difficult to detect by mixing technology. Thus, the process according to the invention realizes a cost-effective preparation process by efficient comminution of straw into a fermentable substrate having an optimum settling surface for anaerobic bacteria. Since it is provided according to the invention to extract air or oxygen from the mixer in a fourth step, an introduction of the anaerobic phase is already carried out in the mixer. As a result, unnecessary air entry into the subsequent anaerobic fermentation process in the biogas plant is largely prevented; because every oxygen input into the anaerobic digestion process in the biogas plant can leave damage to the bacterial culture. Preferably, the method according to the invention is realized in such a way that the negative pressure is generated by a suction device provided on the mixing device.

The device according to the invention for the production of a ready-prepared fermentation substrate builds on the generic that the fermentation substrate mixture is at least temporarily arranged before reaching the biogas plant in a space in which with respect to an atmospheric pressure, a negative pressure can be generated to obtain the ready-prepared fermentation substrate. This results in the explained in connection with the method according to the invention advantage in the same or similar manner, so reference is made to avoid repetition to the corresponding statements in connection with the inventive method.

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

The device according to the invention can advantageously be further developed in such a way that the mixing device comprises the space which serves to mix the organic substances and in which the negative pressure can be generated.

Furthermore, the device according to the invention can be designed such that the organic substances are chaff, manure, in particular low-viscosity manure, and solid manure. In addition, the device according to the invention can also be realized so that the chaff is plant straw.

Particularly preferably, the device according to the invention is realized in such a way that the mixing device is formed by a free-fall mixer.

Alternatively, the device according to the invention can also be designed so that the mixing device is formed by a vertical mixer.

Furthermore, the device according to the invention is preferably realized in such a way that the free-fall mixer is suitable for carrying out a single manure feed via a slurry supply line.

Furthermore, however, the device according to the invention can also be further developed in such a way that the vertical mixer is suitable for making a multiple, time-spaced manure supply via a slurry supply line.

Preferably, the device according to the invention is developed such that a suction device provided on the mixing device is provided, via which the negative pressure can be generated.

The system according to the invention with a biogas plant is distinguished by the fact that the biogas plant can be supplied with a ready-prepared fermentation substrate produced by the process according to the invention and / or by the device according to the invention. A preferred embodiment of the invention will be explained below by way of example with reference to FIGS.

Show it:

Figure 1 is a schematic representation of a first embodiment of the device according to the invention for the production of a fermentation substrate in a side view, which is suitable for carrying out the method according to the invention;

Figure 2 is a schematic representation of the device according to the invention of Figure 1 in a plan view;

Figure 3 is a schematic representation of a second embodiment of the apparatus according to the invention for producing a fermentation substrate in a plan view, which is suitable for carrying out the method according to the invention;

Figure 4 is a schematic representation of a third embodiment of the apparatus according to the invention for producing a fermentation substrate in a side view, which is suitable for carrying out the method according to the invention;

Figure 5 is a schematic representation of the device according to the invention of Figure 4 in a further side view; and

Figure 6 is a schematic representation of the device according to the invention of Figure 4 in a plan view. 1 shows a schematic representation of a first embodiment of the device 10 according to the invention for the production of a ready-prepared fermentation substrate in a side view, which is suitable for carrying out the inventive method. On the other hand, FIG. 2 shows a schematic representation of the device 10 according to the invention from FIG. 1 in a plan view. The device 10 for producing a ready-prepared fermentation substrate comprises in this embodiment a free-fall mixer 12, which is designed in the manner of a known concrete mixer with a rotatable drum (drum mixer). 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. In this case, the drum can be pivoted into a feed and discharge position in such a way that the fermentation substrate can be supplied to it via the inlet and outlet opening. 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 raise in mixed positioning the supplied fermentation substrate, which then falls by gravity back down. When the drum rotation direction is changed, the blades convey the fermentation substrate to the inlet and outlet openings and, together with the displacement of the drum into the feed and discharge positions, the drum is emptied. The free-fall mixer 12 can furthermore be closed by a hydraulically sealing or fluid-sealing flap which is suitable for opening and closing the inlet and outlet openings of the drum. In addition, the free fall shear 12 modified so that is connected by opening into the drum suction on the full closure flap 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, a discharging line which leads into the transfer container bottom or transfer container bottom is provided, via which the ready-prepared fermentation substrate can be discharged into a heat exchanger of a biogas plant of no further interest by means of an eccentric screw pump 24.

The inventive method for producing the ready-prepared fermentation substrate using the device 10 according to the invention is as follows. In the method according to the invention, straw chaff and animal excreta in the form of solid manure and low-viscosity güls are used for the production of the fermentation substrate in this embodiment. 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. It can do that Straw chop, for example, from a straw shredder, not shown, with electric drive and be blown through a fan in the straw blower line 16, which feeds the straw chaff 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 chop 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 in the free fall mixer 12, wherein almost simultaneously or shortly delayed an admission of fresh manure via the Frischgüllezuführleitung 18 and a promotion of solid manure via the conveyor 20 takes place. Subsequently, the free-fall mixer is operated to mix the organic substances in the drum and moved into its mixing position. This feeding operation of the organic matters is controlled by, for example, a weighing device provided on the tumbler mixer 12 and controlled so that a desired mixing ratio of manure / solid manure to straw chopper can be adjusted. In particular, a metering of the individual substrate components, namely the filling of the drum of the tumbler mixer with straw by weight and with liquid manure can be carried out 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. By doing

Free-fall mixer 12, any desired substrate mixture can be effectively produced, while at the same time ensuring that the supplied fresh manure from the fixed Substances, such as solid manure and the straw chaff, is completely bound 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 fluidly coupled to the drum rotating vacuum pump. As a result, the anaerobic phase of the fermentation substrate is initiated. Air collects in particular in the drum of the free-fall mixer above the fermentation substrate and is sucked off with the normally rotating vacuum pump provided on the drum so that the atmospheric pressure in the drum is reduced from 1013.25 mbar by 100 mbar to 913 mbar. The ready-mixed substrate corresponds to the desired substrate mixture of substrate, the drum is opened via the flap, the direction of rotation of the drum is set to empty the drum and the fermentation substrate mixture is supplied via the transfer funnel 14 to the eccentric screw pump 24, which supplies the desired fermentation substrate mixture. tion in the biogas plant, which is not of further interest, which conveys upstream heat exchangers. The resulting treated fermentation substrate then has a pH of 7.4 and consists of 7% by weight straw and 93% by weight slurry / solid manure; Bovine manure is preferably used. Likewise, the fermentation substrate can also be made from pig manure, which has a pH of 7.6, the substrate then consists of 15 percent by weight of straw and 85 percent by weight pig manure / solid manure. The substrate mixture can also consist of several and different animal excrements as well as of solid manure and straw. The mixing always takes place according to the predetermined conditions of the pH and according to the specific desired C / N ratio. Figure 3 shows a schematic representation of a second embodiment of the device according to the invention for the production of a fermentation substrate in a plan view, which is suitable for carrying out the method according to the invention. In the description of this embodiment will be discussed below to avoid repetition only to the differences from the first embodiment. The same or similar components are denoted by the same reference numerals for the first embodiment. 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, at 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 analogously to the transfer container 14 of the first exemplary embodiment, via which the fermentation substrate mixture can be supplied by the free-fall mixers 12 of an eccentric screw pump 24 in order to feed the fermentation substrate mixture via a line 30 to a heat exchanger of the biogas plant of no further interest , The inventive method can be carried out in the second embodiment, mutatis mutandis, as in the first embodiment, only with the difference that two free-fall mixer must be filled and emptied sen to achieve the finished processed fermentation substrate in the desired Gärsubstratmenge.

FIG. 4 shows a schematic representation of a third exemplary embodiment of the apparatus 100 according to the invention for producing a ready-made fermentation substrate in a side view, which is suitable for carrying out the method according to the invention. Furthermore, FIG. 5 shows a schematic representation of the device 100 according to the invention from FIG. 4 in a further side view, while FIG. 6 shows a schematic representation of the device 100 according to the invention from FIG. 4 in a plan view. In this exemplary embodiment, the device 100 according to the invention 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, wherein the vertical mixers 112 are, however, modified in a specific manner, as shown by way of example below the vertical mixer 112 will be explained. The vertical mixer 112 includes a container 138 and a hinged modified cap 134 having two vents 133 and a suction port 132 to which, for example, a vacuum pump (not shown) may be connected to create a vacuum in the vertical mixer 112, particularly in the container 138 to be able to, in particular to 913mbar.

The suction port 132 and the vacuum pump at least partially form a suction device. Furthermore, on the vertical mixer 112, a jacket heating for heating the Fermenting substrate mixture provided in the container 138 of the vertical mixer 112. In addition, the apparatus 100 according to the invention comprises a straw shredder 126 with a fan, via which straw chaff can be fed to the vertical mixer 112 or to both vertical mixers 112 via a straw blower unit 116. In particular, the straw chop is at an upper edge of the vertical mixer 112 partially forming container 138 which can be closed via the cover 134, fed via the straw blower line 116. Furthermore, a slurry feed line 118 is provided, via which fresh liquid manure can also be fed to the container 138 of the vertical mixer 112 at the upper edge of the container. 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 ventilation 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 in particular are opened when blowing 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 fermenting substrate mixture from the container 138 by means provided in the container 138 longitudinal screw conveyors 140 is fed to a not further interest further Gärsubstratmischer a biogas plant. The vertical mixer 112, the transverse screw conveyor 124 and the further mixer of no interest are preferably located in an air-conditioned room with corresponding inlet and outlet 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 according to the invention is adapted with regard to its 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 greater.

The inventive method for the production of fermentation substrates, in particular from straw chaff, manure and animal excrement in the form of solid manure, designed as follows. First, the straw shredder 126 is operated via an electric drive, so that the straw chaff is supplied to the container 138 of the vertical mixer 112 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 weight percent). Due to the fact that the manure / solid manure / straw mixture has a dry matter content of 41.5%, it is not yet pumpable. This mixture is referred to below as the mixture of the preparation stage I or quality level 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 initiates a self-heating phase. This begins already after a few hours from preparation of the mixture of the treatment stage I and can reach in one day a temperature of 40 ⁰ C and more. 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 substance 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 subsequently classified as a mixture of Preparation Stage III or Qualification level 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 feed the finished processed fermentation substrate to the biogas plant which is of no further interest.

In an alternative embodiment, it is provided that the fermentation substrate mixture is generated 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 4 to 6 mutatis mutandis transferred to this alternative embodiment.

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 mixers 14 transfer containers or transfer funnels

16 straw blower line

18 slurry supply line

20 conveyor with conveyor belt

22 funnel for solid manure 24 eccentric screw pump

26 straw shredders 28 blowers

30 line

32 drum flap with suction openings 100 device

112 vertical mixer

116 straw blower line

118 slurry supply line

124 Worm conveyors (cross-auger conveyor) 126 straw shredders

132 suction opening

133 breather holes

134 Lid

136 vertical mixing screws 138 containers

140 longitudinal screw conveyors

Claims

1. A method for producing a ready-prepared fermentation substrate, which is provided in particular for biogas production in a biogas plant, in which organic substances are mixed by a mixing device (12, 112) for the preparation of the fermentation substrate, to obtain a fermentation substrate mixture, characterized in that Fermentation substrate mixture is placed before reaching the biogas plant at least temporarily in a room in which with respect to an atmospheric pressure, a negative pressure is generated in order to obtain the finished processed fermentation substrate. 2. The method according to claim 1, characterized in that the negative pressure in the mixing device (12, 112) is generated, in which the fermentation substrate mixture is arranged. 3. The method according to claim 1 or 2, characterized in that are used as organic materials chaff, manure, in particular liquid manure, and solid manure, which are mixed by the mixing device (12; 112) to the Gärsubstratgemisch. 4. The method according to claim 3, characterized in that as chaff plant straw is used, which is mixed with the manure and the solid manure by the mixing device (12 12) to the Gärsubstratgemisch. 5. The method according to any one of claims 1 to 4, characterized in that the mixing of the organic substances by a free-fall mixer (12) is made as a mixing device. 6. The method according to any one of claims 1 to 4, character- ized in that the mixing of the organic substances by a vertical mixer (112) is performed as a mixing device. 7. The method according to claim 5, characterized in that the mixing of the organic substances by the free fall mixer (12) takes place under a single slurry. 8. The method according to claim 6, characterized in that the mixing of the organic substances by the vertical mixer (12) takes place with repeated, time-spaced manure feed. 9. The method according to any one of claims 1 to 8, characterized in that the negative pressure by a at the mixing device (12; 112) provided for suction device (32; 132) is generated. 10. Apparatus for producing a ready-prepared fermentation substrate, which is provided in particular for biogas production in a biogas plant, with a mixing device (12, - 112), which is suitable for the treatment of the fermentation substrate to mix organic substances to obtain a fermentation substrate mixture, characterized in that the fermentation substrate mixture is at least temporarily arranged before reaching the biogas plant in a room in which respect At atmospheric pressure, a negative pressure can be generated to obtain the finished fermentation substrate. 11. The device according to claim 10, characterized in that the mixing device (12, 112) comprises the space which serves for mixing of the organic substances and in which the negative pressure can be generated. 12. The apparatus of claim 10 or 11, characterized in that the organic matter chaff, manure, in particular low-viscosity manure, and solid manure. 13. The apparatus according to claim 12, characterized in that the chaff is plant straw. 14. Device according to one of claims 10 to 13, characterized in that the mixing device is formed by a free fall mixer (12). 15. Device according to one of claims 10 to 13, characterized in that the mixing device is formed by a vertical mixer (112). 16. The apparatus according to claim 14, characterized in that the free-fall mixer (12) is adapted to make a single manure supply via a slurry supply line (18). 17. The device according to claim 15, characterized in that the vertical mixer (12) is adapted to make a manure supply line (118) a multiple, time spaced te slurry manure. 18. Device according to one of claims 10 to 17, characterized in that one at the mixing device (12; 112) provided suction device (32; 132) is provided, via which the negative pressure can be generated. 19. System with a biogas plant to which a ready-made fermentation substrate produced by the method according to one of claims 1 to 9 and / or by the device according to one of claims 10 to 18 can be fed.