EP1907139A1

EP1907139A1 - Method and plant for multistage hydrolysis of solid biogenic raw materials

Info

Publication number: EP1907139A1
Application number: EP06761833A
Authority: EP
Inventors: Günter Busch; Jochen Grossmann
Original assignee: Gicon Grossmann Ingenieur Consult GmbH
Current assignee: Gicon Grossmann Ingenieur Consult GmbH
Priority date: 2005-07-26
Filing date: 2006-07-25
Publication date: 2008-04-09
Also published as: WO2007012328A1; DE112006001877A5

Abstract

The invention relates to a method and a plant for multistage hydrolysis of solid biogenic raw materials having percolators (Hl, H2, H3) having subsequent generation of biogas (R1) exclusively from the hydrolysate. According to the invention, for this, a plurality of quantities of solid biogenic raw materials are hydrolysed staggered in time, the hydrolysate running off from the fresher amount in each case being fed to the next oldest amount as percolate. The plant comprises a plurality of hydrolysis devices, preferably percolators.

Description

Process and plant for the multistage hydrolysis of solid biogenic raw materials

The invention relates to a process and a plant for the multistage hydrolysis of solid biogenic raw materials by percolation with subsequent production of biogas exclusively from the hydrolyzate.

The degradation of biodegradable substances (hereinafter referred to as biogenic substances) during operations in biogas plants takes place in several successive biochemical substeps in an aqueous environment. In the first step (hydrolysis), water-soluble components are dissolved out of the solid biogenic substances. Furthermore, non-water-soluble biogenic substances are decomposed into water-soluble, generally low molecular weight substances by several types of extracellular enzymes which are produced by different microorganisms. Enzymes can also be added as so-called foreign enzymes to accelerate or facilitate certain degradation processes. Hydrolysis bacteria and enzymes are mainly in the aqueous solution, but can also be located on solid surfaces.

In the biochemically following acidogenesis (second partial step), these substances formed in the hydrolysis or converted into the aqueous solution are converted into various organic acids (lower fatty acids, amino acids), which are then converted into acetic acid in the third partial step (acetogenesis). The acetic acid is then degraded in the methanogenesis (4th sub-step) using methane bacteria to methane and carbon dioxide.

These processes take place in parallel in single-stage biogas plants. It is known that the ratio of the concentrations of the various intermediates of the above-mentioned process stages allows statements about the stability and thus can be used to control the biogas process. Furthermore, it is generally known that the acids produced in the acidogenic and acetogenic phases reduce the pH. Since the microorganisms of the methane level only exist in the vicinity of the pH value 7 (neutral range) and can thus form biogas, biogas plants generally have the risk of acidification, characterized by the death or inhibition of the methane bacteria and the decrease in the pH , and thus the process failure. One stable process equilibrium is achieved when the production of acids equals their consumption.

In two-stage procedures, the sub-steps of hydrolysis and acidogenesis (first stage) of the sub-steps acetogenesis and especially methanogenesis (second stage) are separated apparatus and process technology. As a result, a better controllability and a higher stability of the method is achieved. In common usage, the first stage of the two-stage biogas process is often referred to only as hydrolysis and the second stage as a methane stage. The aqueous solution leaving the hydrolysis is commonly referred to as hydrolyzate. In the following, this simplistic language is also used.

Scientific studies and practical experience have shown that the methane bacteria of the methane stage are highly productive and can convert a large amount of the hydrolysis products into biogas. For the effectiveness, d. H. For the rate of conversion of the degradable organic substance from solid biogenic input materials to liquid hydrolyzate and for the biogas productivity of a biogas plant, hydrolysis is considered to be an intensity limiting step.

It is known that the effectiveness of the hydrolysis depends on the amount or concentration as well as the type of hydrolysis bacteria and the extracellular enzymes they produce. Furthermore, optimal environmental conditions (temperature, nutrient availability) play a role.

Usually, the percolators are operated in parallel, ie the hydrolyzate of each percolator is passed, possibly via an intermediate buffer, into the methane reactor. By superimposing the output of the percolators, whose contents each have different residence times, one expects a homogenization of the hydrolyzate quality and quantity and thus also of the resulting methane gas. (Fig. 1). It is known that the biochemical conversion in the hydrolysis immediately after the entry of fresh input material is very high, since first the rapidly degradable substances are degraded. At this stage, therefore, a very rapid increase in the hydrolysis bacteria takes place, which is also associated with the increased production of enzymes. After the degradation of the rapidly degradable substances, the intensity of the biochemical transformation of the substance slows down, because then increasingly only less degradable substances are available. Simultaneous takes but, due to the limited lifetime of the hydrolysis bacteria and by the constant removal of a hydrolyzate substream in the methane, also the concentration of the hydrolysis bacteria and the enzymes from. As a result, the degradation of poorly biodegradable substances is further reduced. In practice, this degradation must then be terminated for economic reasons, which is associated with a loss of biogas yield.

DE 199 37 876 C2 discloses a process for the biological conversion of organic substances to methane gas, in which organic wastewaters, but no solids, are hydrolyzed. The hydrolyzate is recycled, with an increase in the concentration of hydrolysis bacteria by membrane filtration and recycling of the filter residue. The injection of air is used as a measure for the targeted growth of (aerobic) acidifiers.

DE 199 09 353 A1 describes a process and a plant for processing a mixture of substances contained in an organism. The solid obtained serves as an inoculation material used to initiate the hydrolysis process in the fresh material, but not to increase the concentration.

The process disclosed in DE 40 00 834 A1 is suitable only for pumpable substrates, process and plant are not technically suitable for predominantly solid biogenic raw materials. The biogenic material passes through the hydrolysis as a total material flow, larger solid particles are withdrawn directly from the hydrolysis tanks and led to digestion, a multi-stage digestion is therefore not possible for the solid fraction. The recirculation of sludge takes place only from the overflow of the hydrolysis and is only limited possible because otherwise the throughput of fresh material is reduced too much by the hydrolysis.

DE 198 46 336 A1 comprises many variants for a waste treatment, which include, inter alia, a two-stage hydrolysis. However, this two-stage nature is due to the tasks of mechanical material flow separation to be solved because the hydrolysis apparatus flows continuously through the material stream of the biogenic material, in this case "waste in particular." This is characterized, inter alia, by mechanical transport facilities for the biogenic material is thus only several hours, a maximum of a few days. It is an object of the invention to provide a method and a plant for the hydrolysis of solid biogenic raw materials for the production of biogas, in which the highest possible concentration of hydrolysis bacteria and enzymes under optimum conditions for the hydrolysis of the biogenic raw materials act, a high degree of degradation achieved organic substance in the biogenic raw materials in the shortest possible time and the formation of methane is avoided in the hydrolysis step.

According to the invention, the object is achieved by a process for the multistage hydrolysis of solid biogenic substances in which a plurality of solid biogenic raw materials are hydrolysed in a time-shifted manner, the drolysate being discharged from the fresher quantity being fed to the next-largest amount as percolation liquid.

The solution according to the invention is particularly applicable to biogas plants and processes, which are characterized by a separate hydrolysis stage before the actual biogas production stage (Methansrufe) and use the solid biogenic raw materials as the main feedstock (primary energy source).

As solid biogenic raw materials all hydrolysed degradable substances of plant and animal origin, biogenic waste and waste mixtures can be used, provided that they have a percolation permeability sufficient for the percolation process for the percolate (ie a permeability). This permeability can also be achieved by the addition of structural materials that may be reusable.

The technical measure which serves to achieve the objective of the invention, the material flow of the hydrolyzate in the percolation process in a kind of series connection via each spatially delimited subsets of present in homogeneous bed biogenic input material. According to the invention, several quantities of solid biogenic raw materials but also portions of the biogenic raw materials can be hydrolyzed with a time offset. For a process according to the invention, at least two, but more preferably three or more, approximately equal amounts or partial amounts of input material are required.

For the individual quantities or partial quantities, the hydrolysis process is started at different times, the time interval of the beginning of the process is determined as follows: Total duration of the hydrolysis process (biochemically required period up to which most of the organically degradable substance has been released from the solid biogenic input material so that the hydrolysis process can be stopped)

divided by

Number of individual quantities or subsets.

The material flow guide is characterized in that the newly introduced into the process amount of biogenic raw material is percolated with liquid that has only a low concentration of organically degradable solutes, but hydrolysis bacteria and enzymes and a high nutrient concentration (eg., Liquid from the process the methane level). The rapidly biodegradable substances present in fresh biogenic raw material lead to a rapid multiplication of hydrolysis bacteria and a corresponding increase in the enzyme concentration and the concentration of organic acids. The running of this fresh amount hydrolyzate is now fed to the next older amount as percolation liquid, the expiring of this amount hydrolyzate turn the next older, etc.

This material flow guidance ensures that the high concentration of hydrolysis bacteria and enzymes in fresh input material is still available for the hydrolysis process of older input material, so that a much more efficient degradation of the less degradable organic substance is possible.

Furthermore, it is achieved that the high acid potential (low pH value) from the hydrolyzate of the fresh input subset also ensures a low pH value in the case of percolation of the subsequent subsets. This, in turn, inhibits methane formation, which, on the one hand, ensures a consistent separation between the hydrolysis and the methane stage and, on the other hand, ensures that the enzymes that are important for the hydrolysis are not prematurely decomposed by methane bacteria, which could reduce their concentration.

For technical feasibility of this flow guide corresponding buffer volumes for intermediate storage of the hydrolyzate are connected between the amounts to be percolated. The hydrolyzate in the course of the last percolated subset (which has practically reached almost the total residence time in the hydrolysis process) has the maximum concentration of dissolved organic substances and is - possibly after an intermediate storage - the methane stage fed.

According to claim 2, several percolators are used, wherein the hydrolyzate of a filled with a fresher amount of percolator is fed to each of the percolator with the next-largest amount of filled percolator as Perkolationsflüssigkeit.

For this purpose, several percolators are used, which can be constructed identically and each of which can be equipped with a corresponding buffer. These percolators are now operated in a series circuit, wherein the percolate flow is conducted in quasi-direct current. The percolators are filled or emptied in regular operation with a time interval, so that in the overall process both fresh input material as well as those with a longer residence time, d. H. Already treated with hydrolyzate material - here referred to as older material - finds.

In normal operation, the hydrolyzate from the first, filled with fresh input material percolator now not on the hydrolyzate storage tank directly Methansrufe - as previously customary - but the second filled with older material percolator supplied. Since this hydrolyzate now has a high concentration of hydrolysis bacteria and enzymes, the degradation of the biogenic material is better supported in this stage than would be possible without this partial flow. As a result, the older biogenic raw material achieves a higher degree of degradation of the remaining solid organic substance and its conversion into dissolved organic substances (eg, degradation of hemicelluloses, lignin, and other compounds that are difficult to break down). The hydrolyzate from this stage is now fed to the next one, and so on. In each stage, the concentration of dissolved and already biochemically converted substances increases, which are then passed to the methane stage after the last percolate stage. The total carried freight of dissolved organic matter in the hydrolyzate is ultimately much higher than in the parallel circuit. This increases the specific gas yield from the biogenic raw material. In addition, due to the high concentrations of dissolved organic substances, the amount of liquid in circulation is reduced. An advantageous side effect of this quasi-DC series connection of the hydrolyzate stages is a temporal homogenization of the concentration of Hydrolyzate stream, which is passed into the methane stage on. As a result, the control or control effort is reduced to keep the produced gas quantity and the gas quality constant in the subsequent methane production.

According to claim 5, the access of air is made possible in the hydrolysis step.

It has been found that the acetogenic and methanogenic bacteria, which are usually in the methane stage, contribute significantly to reducing the effectiveness of the enzymes formed by the hydrolysis bacteria. The presence or activity of these methane-forming bacteria in the hydrolysis step must therefore be avoided in order to maintain a high concentration of the enzymes. It is also known that the methane-forming bacteria in the presence of (air) oxygen adjust their activity and possibly killed. According to the invention, the access of air is made possible in the hydrolysis step. Preferably, the hydrolyzate storage containers and also the percolators can be aerated by blowing in air.

Thus, the biochemical activity and the multiplication of the methane bacteria are reduced or avoided.

The supply and consequently the removal of air leads to a gas-side open mode of operation of the hydrolysis. It is known that about 50% of the carbon dioxide formed in the overall process is formed in the hydrolysis. This carbon dioxide is now removed with the possibly registered air and other gases evolving during the hydrolysis by the management according to claim 6 (possibly with treatment via a biofilter to avoid odor emissions). The carbon dioxide therefore no longer appears in the biogas and can therefore no longer "dilute" the methane, as a result of which the biogas leaving the methane reactor downstream of the hydrolysis contains a higher methane content.

The supply of atmospheric oxygen can also be carried out according to claim 4 by the aeration of the recirculated to the hydrolysis process from the Methanstufe.

For a special application of the process, the biogas production from renewable raw materials (eg cereal crops, which in chopped form the As a boundary condition, it should be noted that these feedstocks are usually only harvested in a short period of time during one year. In order to enable continuous biogas production, these substances are usually stored in durable form (silage) in appropriate storage areas.

According to claim 3, an alternative embodiment of the method is to use the storage areas required for temporary storage of these feedstocks directly percolation / hydrolysis. In this case, part of the material stored in the storage area (defined zones, each with separate collection of seep liquid) is directly charged with percolate. The percolate is buffered in one or more buffer stores and can thus be fed several times to the feedstock. A partial stream is discharged directly to the biogas reactor according to the basic method described above.

In order to apply percolate to the various zones of the entire storage area, the irrigation system is made locally variable (for example, by the targeted activation of individual irrigation openings or by the design as a movable / displaceable irrigation system). The percolation of the respective partial surface of the storage area is started with a time delay, so that different degradation states result in the individual subareas of the storage area. As a result, a homogenization of Perkolatqualität and thus the biogas production in the subsequent methane reactor can be achieved.

By a different timing of the zones with and a corresponding liquid management can be realized as an alternative to the parallel circuit, a quasi-DC or series connection. Here, the percolate of the last merged into the percolation operation partial area is applied to a previously passed into the percolation operation partial area with the aim of achieving better degradation of the starting materials. The material flow guidance is thus comparable to the material flow guidance when using percolators in series connection.

According to the invention, the object is achieved by a system for the multistage hydrolysis of solid biogenic raw materials with a plurality of hydrolysis devices for producing biogas, in which the hydrolysis devices are connected with quantities of biogenic raw materials such that they are operable offset in time and the hydrolyzate which runs from a hydrolyzer having a fresh amount is respectively supplied to the hydrolysis device having the next-highest amount as percolation liquid.

The hydrolysis devices are connected according to an advantageous embodiment of the invention with a drain of a methane reactor. The storage volume located after the drain has a device for supplying air. Alternatively, the device for supplying air may also be arranged elsewhere in the connection between drain and hydrolysis devices. This facility ensures that vented effluent of the methane reactor can be used as percolate or percolate additive for the hydrolysis of fresh quantities of biogenic raw materials.

The hydrolysis devices with associated reservoirs and pump wells have means for supplying air.

Advantageously, the hydrolysis devices have means for removing air and gas which develops during the hydrolysis.

According to a further embodiment of the invention, the hydrolysis devices are percolators with a sprinkler device and a device for solid / liquid separation. The percolators have a temporary storage for the hydrolyzate or the percolators are followed by a buffer for the hydrolyzate.

According to the invention, the percolators are connected in such a way that the hydrolyzate proceeding from a fresher quantity is supplied in each case to the next-highest quantity as percolation liquid.

By means of this cascade or staggered arrangement of the percolators, it is possible to repeatedly bring the hydrolysis bacteria and the hydrolyzate enzymes into contact with the solid input material.

According to the invention, a plurality of percolators are used, which can be constructed identically and each of which percolator is provided with a corresponding buffer (eg. larger shaft at the outlet of the percolator) can be equipped. These percolators are now operated in a series circuit, wherein the percolate flow is conducted in quasi-direct current. The percolators are filled or emptied in regular operation with a time interval, so that in the overall process both fresh input material as well as those with longer residence time - referred to here as older material - finds.

In normal operation, the hydrolyzate from the first, filled with fresh input material percolate now on the Hydrolyzatspeicherbehälter not directly the methane level - as previously customary - fed, but the second, filled with older material percolator. Since this hydrolyzate now has a high concentration of hydrolysis bacteria and enzymes, the degradation of the biogenic material is better supported in this stage than would be possible without this partial flow. The hydrolyzate from this stage is now fed to the next, etc. In each stage, more and more organic dry matter of the biogenic raw materials is degraded. In the end, the degree of degradation of biogenic substances is significantly increased. The cargo of hydrolyzed organic substances, which are then passed into the methane stage after the last percolate stage - possibly after buffer storage - increases accordingly, so that the economy of the process improves because of the higher specific yield of biogenic raw materials. In addition, the concentration of organic substances in the hydrolyzate increases from stage to stage (see Fig. 3). This increases the specific gas yield of the methane reactor, which can now be built smaller. In addition, the amount of liquid in circulation decreases.

As an advantageous side effect of this quasi-DC series connection of the hydrolyzate stages, a temporal equalization of the concentration of the hydrolyzate stream which is conducted into the methane stage occurs. This reduces the control or regulation effort to keep the produced gas quantity and the gas quality constant.

According to an advantageous embodiment of the invention (Fig. T), a single pump shaft is used for all percolators (in Fig. 2 eg 3 percolators). The stepped material flow guide is achieved by the fact that the inlet to the pump shaft via a valve control at the end of the buffer only one percolator and accordingly at a certain time only the spraying with hydrolyzate takes place only in a percolator. After a set period of time is the percolation is interrupted, the inlet valve of the next buffer is opened and the percolation is switched over to the next corresponding assigned percolator. The effluent of the percolator with the oldest material is directed to the reservoir, from which the highly enriched hydrolyzate is metered into a methane stage.

As a hydrolysis also mobile percolators can be used with stationary or movable sprinkler.

A further advantageous embodiment of the plant according to the invention consists in using the flax silos required for intermediate storage of the feedstocks (for example maize silage) directly for percolation / hydrolysis. In this case, each part of the material stored in the flax silo is directly exposed to percolate. The percolate is buffered in one or more buffer stores and can thus be fed several times to the feedstock. A partial stream is discharged directly to the biogas reactor according to the basic method described above.

In order to apply percolate to sub-areas (individual zones) of the entire storage area, the irrigation system is made locally variable (for example, by the targeted control of individual sprinkler openings or by the design as a movable / movable sprinkler system). The percolation of the respective zone in the storage area is started with a time delay, resulting in different degradation states in the individual zones. As a result, a homogenization of Perkolatqualität and thus the biogas production in the subsequent methane reactor can be achieved.

By a different timing of the zones with percolate and a corresponding liquid management can be realized as an alternative to the parallel circuit, a quasi-DC or series connection. Here, the percolate of the last merged into the percolation operation partial area is applied to a previously passed into the percolation operation partial area with the aim of achieving better degradation of the starting materials. The material flow guidance is thus comparable to the material flow guidance when using percolators in series connection. With reference to accompanying drawings, an embodiment of the invention will be explained in more detail. Show

Fig. 2 flow diagram of an example plant with 3 percolators

Fig. 3 Scheme of the solution according to the invention with multi-stage flow control of the hydrolyzate

2 shows a flow diagram of a plant for the production of biogas with 3 percolators H1 to H3 and a methane reactor R.

The percolators H1 to H3 have the same structure, are lined with an acid-proof lining and can be loaded and unloaded using conventional technology, for example wheel loaders.

The percolators H1 to H3 each have a sprinkler for the supply of percolate and in each case a sieve plate, which allows a solid / liquid separation of the hydrolyzate from the fixed bed.

The percolators H1 to H3 are each followed by a buffer ZW1 to ZW3, which collects the hydrolyzate leaving the fixed bed.

Below the sieve trays a system for supplying air is arranged, through which the fixed bed can be ventilated if necessary.

The percolators H1 to H3 are connected via a collecting air line with a biofilter BF for exhaust air removal and purification and odor neutralization.

The latches ZWl to ZW3 are connected via valves with controllable and lockable connection lines with the pump shaft Pl.

Via connecting lines, the pump shaft Pl is connected to the sprinkler systems of the percolators H1 to H3 and to a reservoir S1. The hydrolyzate collecting in the pump shaft with pump P1 can be equipped with a heat exchanger W1 (for setting the optimum temperature for the hydrolysis process) Connecting line the respective sprinkler systems of percolators Hl to H3 are supplied as percolate.

Memory Sl is connected to the methane reactor Rl for biogas production. Via this connecting line, the methane reactor can be supplied with the aid of the pump P2 hydrolyzate. In the heat exchanger W2 the optimum temperature for the methane production of the hydrolyzate is set.

Alternatively, hydrolyzate from the reservoir Sl by means of the pump P3 via the heat exchanger Wl again be supplied to the percolators, z. B. if the hydrolyzate has not yet reached the optimum concentration of organic matter.

Memory S2 allows the intake of effluent from the methane reactor Rl.

Memories Sl and S2 each have a means for supplying air.

Vented drain can be supplied via a connecting line from the reservoir S2 by means of the pump P4 the sprinkler of the percolator with fresh biogenic raw material. The valve control associated with the connection line allows a corresponding supply line.

Buffer, pump shaft and memory Sl and S2 have a sludge outlet.

Excess liquid produced in the overall process is discharged from the container S2 and can be filled into tank trucks by means of pump P5 and utilized externally (preferably as fertilizer for closing nutrient cycles).

The plant of Fig. 2 operates as follows:

In normal operation, the percolators Hl to H3 are filled at different times with biogenic raw materials. For example, percolator H3 may have the oldest charge, percolator H2 may have the next charge, and percolator H1 may just have been refilled. From the storage unit S2, the aerated discharge from the methane reactor Rl is fed via the sprinkler system to the percolator Hl filled with fresh input material. This percolate has only a low concentration of degradable organic matter, but enzymes, hydrolysis bacteria and in particular nutrients. The effluent from the fixed bed of percolator Hl hydrolyzate is collected in the buffer ZWl, fed to the pump shaft Pl and fed from there via the connecting line and a heat exchanger of the sprinkler system of the percolator H2. The hydrolyzate passing through the fixed bed is collected in the buffer ZW2 and, after the pump shaft P 1 has been emptied, transferred to it.

The hydrolyzate collected in the pump shaft Pl is supplied to the sprinkler system of the percolator H3 via the corresponding connecting line with associated heat exchanger, collected after passing through the fixed bed in the buffer ZW3 and, after emptying the pump shaft, transferred to the storage device S1 for forwarding. From the storage 1, the enriched percolation liquid can then be fed to the methane reactor Rl.

Fig. 3 shows a scheme of the inventive solution based on 3-stage current control of the hydrolyzate as shown in Scheme Fig. 2. Clearly visible is the achievable additional degradation of the organic dry matter (oTS) and thus the increase in the cargo of hydrolyzed organic substances in a row. For comparison, the achievable degradation of organic dry matter is shown in parallel operation.

reference numeral

H Ibis H 3 percolators 1 to 3

ZWl to ZW3: Buffers 1 to 3

BF biofilter

Wl heat exchanger 1 (inlet percolators)

W2 heat exchanger 2 (inlet methane reactor)

Pl Pump 1 in pump shaft (circulation pump percolation and inlet to

Memory 1)

P2 pump 2 feed methane reactor

P 3 pump for percolation with supply from storage tank 1

P4 pump for percolation with supply from storage tank 2

P5 pump discharge excess water

51 storage 1 (enriched hydrolyzate)

52 Storage 2 (effluent methane stage) Rl Methane Reactor

Claims

claims

1. A process for the multistage hydrolysis of solid biogenic substances for the subsequent production of biogas, characterized in that a plurality of solid biogenic raw materials are hydrolyzed offset in time, wherein the draining of the fresher amount Hy drolysat each of the next older amount is supplied as percolate.

2. The method according to spoke 1, characterized in that a plurality of percolators are used, wherein the hydrolyzate of a filled with a fresher amount of percolator each percolator filled with the next-fuller amount percolator is supplied as percolate.

3. The method according to claim 1, characterized in that individual zones of a storage area of biogenic raw materials are used for the hydrolysis.

4. The method according to any one of claims 1 to 3, characterized in that is used as percolate or Perkolatzusatz for the percolation of the freshest amount of biogenic raw materials aerated effluent from the methane stage.

5. The method according to any one of claims 1 to 4, characterized in that the activity and the proliferation of ubiquitously present or recorded during the process of methane bacteria in the hydrolysis is hindered or avoided by the supply of air.

6. The method according to any one of claims 1 to 5, characterized in that excess air and developing during the hydrolysis gas are removed from the process.

7. The method according to any one of claims 1 to 6, characterized in that are hydrolyzed as amounts of portions of the biogenic raw materials offset in time.

8. Plant for multistage hydrolysis of solid biogenic raw materials with a plurality of hydrolysis facilities for the subsequent production of biogas, characterized in that the hydrolysis with amounts of biogenic raw materials so are switched, that they are operated offset in time and that of a

Hydrolyzer with fresher amount running hydrolyzate in each case the hydrolysis device with the next-largest amount is fed as percolation liquid.

9. Plant according to claim 8, characterized in that the hydrolysis devices are connected to a drain of a methane reactor, that the drain has a ventilation device or that in the connection between drain and Hydrolysis a ventilation device is arranged, so that vented expiration of the methane reactor as percolate or Perkolatzusatz can be used for the hydrolysis of fresh quantities of biogenic raw materials.

10. Plant according to claim 8 or 9, characterized in that the Hydrolyseeinrichtungen have means for supplying air.

11. Plant according to one of claims 8 to 10, characterized in that the hydrolysis devices have means for removing air and developing during the hydrolysis gas.

12. Plant according to one of claims 8 to 11, characterized in that the hydrolysis are percolators with a sprinkler and a device for solid / liquid separation, that the percolators have a buffer for the hydrolyzate or that the percolators a buffer for the hydrolyzate is connected downstream ,

13. Plant according to one of claims 8 to 12, characterized in that the hydrolysis are mobile percolators with stationary or movable sprinkler.

14. Plant according to one of claims 8 to 10, characterized in that are used as hydrolysis individual zones of a storage area of biogenic raw materials.