DE102018002883A1 - Process for the batchwise use of fully mixable agitators for methane fermentation - Google Patents

Abstract

The invention relates to a method for the batchwise use of fully mixable Rühparparaten for methane fermentation.
For this purpose, the batchwise biotechnological treatment is carried out in the respective treatment station in at least two process containers. The process containers of the respective treatment station are equipped with microcultures adapted to the substrates used.
After the filling of a process container with substrate from the upstream processing station this container is neither fed nor emptied while maintaining the selected mesophilic or thermophilic environment for a period of between 5 and 15 days.
Before re-feeding the batchwise operated process container this is emptied to a minimum level of at least 20 to 40% in the subsequent processing station, the remaining substrate residue acts as a seed culture for the subsequent batchwise substrate treatment.

Description

Field of use:

The invention relates to a method for the batchwise use of fully mixable Rühparparaten for methane fermentation. Such a process is needed for bioenergy production by means of methane fermentation using lignocellulose-rich biogenic raw materials and residues.

State of the art:

With the DE 4446661 C1 (1994) discloses a technical solution for the multi-stage anaerobic treatment of biogenic feedstocks, which is characterized by the spatial separation of hydrolysis and fermentation.

In the article "Biogas from solid manure" on the occasion of the 8th Scientific Conference on Organic Farming in Kassel (2005), a two-phase biogas reactor for continuous fermentation of solid manure and organic waste was presented. Characteristics of this method proposal is the coupling of a large volume anaerobic Hydrolysefermenters with a downstream Methanisierungsfermenter for the thin phase, which is obtained from the hydrolyzate in addition to a compostable solid phase by means of phase separation.

The dissertation "Kinetics of Biogas Production from Renewable Raw Materials and Manure" at the HUB Berlin (2007) concludes from batchwise fermentation tests to preferable process designs. It is inferred that by means of comparative batchwise investigations, while ensuring uniform assessment conditions, such influencing variables are important for the fermentation success of biogenic starting materials, such as room load, process temperature, inhibitor concentration, lignin content, average pH of the fermentation substrate, average anaerobic treatment time and the like. etc. ..

The EP 2242848 B1 (2008) discloses a method of producing biogas characterized by the addition of an externally generated cell culture of the species Clostridium sartagoformum to the biomass used amounting to at least 1% of the total number of microorganisms present in the culture.

At the biogas symposium in 2008, research results on the hydrolysis of biogas plants were obtained, which were obtained from the monofermentation of renewable raw materials. Attention is drawn to the advantages of batchwise aerobic prehydrolysis.

In "Progress in Biogas Stuttgart-Hohenheim" (2011) reference is made to the higher efficiency and the improved process stability and controllability of biogas production in the case of the separation of hydrolysis and methanation. This should enable higher organic plant loads and shorter retention times. In particular, the hydrolysis should be carried out batchwise and combined with a continuous methane fermentation.

A method for the pressure methanization of biomass is with the DE 102011015415 A1 (2011). For this purpose, a high pressure reactor suitable for pressure methanogenesis should be used, with the aid of which biogas with a methane content of at least 80% by volume should be produced. The method exploits the insight that the separation of the fermentation phases "hydrolysis + acidogenesis" in a primary fermenter and the "acetate formation + methanogenesis" in a secondary fermenter is advantageous. This should make it possible to use high-performance fixed bed reactors for methane formation. Preferably, the pressure above the normal pressure in the reactor should be generated at least partially by the methanogenic microorganisms themselves. The prerequisite for the use of fixed bed reactors is the recovery of a liquid percolate, which was previously largely removed from the remaining solids. In contrast, continuous or discontinuous solid, dry or liquid reactors can be used to recover an intermediate product from which the percolate is withdrawn.

With the DE 102012005636 A1 (2012) discloses a process for the production of biogas, which envisages the use of very finely divided calcium carbonate in order to increase the buffer capacity of the organic substrate used. This is intended to control the pH of the fermentation substrate between 6.3 and 8.0. The proposed method should optionally be able to be carried out in a batch process in which a reactor is initially completely filled and completely emptied again after a reaction time.

In the agrautee (2016) a two-part biogas plant is reported, with the help of which the gas yield could be increased by up to 18%. In this case, the actual biogas reactor was preceded by a likewise anaerobically operated hydrolysis container, the resulting hydrogen-rich hydrolysis gases being introduced into the latter to improve the gas quality of the methane fermenter. The hydraulic residence time in the hydrolysis fermenter should be between 3 and 5 days at a process temperature between 20 and 30 ° C.

The VDI guideline 4630 provides for the determination of the developable biogas potential by means of a batch test. Thus, among other things, methane formation potentials are to be determined for biogenic feedstocks of different composition. An essential requirement is the assessment of the so-called percolate used for the treatments. It is considered to be sufficiently well-suited if a required minimum conversion of the organic model substance to methane is achieved within a predetermined period of time from a defined biogenic model substance while maintaining prescribed physical experimental conditions.

The hitherto known technical solutions for the batchwise implementation of fermentation processes, in particular those for methane fermentation adheres to the common deficiency that neither the possibilities for the provision of the composition of the respective biogenic feedstock adapted and selected microculture are provided, nor that technical solutions for the permanent preservation of this adapted culture.

Object of the invention:

The object of the invention is therefore to provide a technical solution with which the deficiencies of the prior art are overcome. In particular, it is about the development of proposals, by means of which proven agitators available in large quantities in existing methane fermentation plants the conditions for the biotechnological fermentation of biogenic feedstocks of different composition over a selectable minimum treatment time and at the same time with the help of adapted to the respective fermentation task microcultures can be made available.

Description of the invention:

The object of the invention is achieved by the method proposed in claim 1. Advantageous embodiments of the invention are explained in the subclaims.

Thereafter, the inventive method for the use of fully mixable agitators for batchwise methane fermentation in plants for biogas production from raw fiber-rich biogenic feedstocks is realized that in spatially separate stations initially from finely divided feedstocks and biofilms, which are obtained as a thin phase in the phase separation of the fermentation residues, a pumpable biosuspension is produced. In a subsequent station, the biosuspension is pretreated hydrolytically. The hydrolysates obtained from the biosuspension used are first fed to a methane fermentation in the preferably mesophilic medium, while the fermentation substrates formed during the methane fermentation are subjected to further treatment in a secondary fermentation station, which is preferably operated in the thermophilic environment.

It is provided that the batchwise biotechnological treatment is carried out in the respective processing station in at least two process containers, these process containers are equipped with specially adapted to the biogenic substrates used microcultures. These special microcultures can be taken from already operated with similar feedstock processes or can be obtained during ongoing plant operation by selective and adaptive measures.

It is characteristic of the solution according to the invention that the process container filled with substrate from the upstream processing station is neither charged nor emptied during a period of between 5 and 15 days and that the treatment of the substrate in the respective process container involves mixing with the seed material contained in the process container , limited to the tempering and the gassing promoted circulating. The substrate treatment is carried out batchwise at least in the post-fermentation station, with the fermentation residues obtained in the secondary fermentation station being intermediately stored in a storage tank arranged behind the secondary fermentation station. The available useful volume of this storage tank corresponds to at least the volume of the fermentation residues, which must be taken periodically before the process container of Nachfermentationsstation before refilling.

In a preferred embodiment, the respective process container of a main fermentation station operated batchwise is neither charged nor emptied after complete filling with hydrolyzate for a period of at least 5 days. This takes into account the observation that the short-chain fatty acids contained in the hydrolysates used and essential parts of the easily degraded fats, crude proteins and carbohydrates are reduced as far as in the fermentation substrate in order not to use the microculture predominantly active there in the post-fermentation station for the metabolization of the crude fiber-rich Sustainable deformation of feedstocks.

A further advantageous embodiment provides, in each case completely filled up process container in the thermophilic environment operated Nachfermentationsstation least for a period of at least 10 days regularly neither to load nor to empty. In particular, two findings are met: First, the effects of at least 10 days substrate treatment in the thermophilic environment are used for a recognized full-flow sanitation. Secondly, it is avoided that the germs active for the metabolisation of the raw-fiber-containing ingredients are flushed out with generation times of more than 8 days to reduce activity.

It has proven to be advantageous to limit the entry of mechanical stirring energy in the batchwise operated process containers to the extent to which, as a result of the regular circulation of the contents of the respective process container obstructions of the gas release by solidifying floating layers are avoided and the remaining process conditions largely constant being held

In the interest of using adapted to the changing substrate qualities in the successive stages microcultures emptying of the treated substrates from a batchwise operated process vessel is carried out in the subsequent processing station such that only a partial emptying takes place and remaining in the process container substrate for subsequent batch treatment as adapted and regrowing vaccine mass acts. For this purpose, a substrate residue of at least 20%, but preferably of at least 40%, of the useful volume of the respective process container should remain in the respective empty process container.

According to a further embodiment, the overloading of the microcultures in the fermentation stations is to be prevented by carrying out the daily loading of a partially emptied process container of the batchwise operated processing station with hydrolyzate from the hydrolysis station or with fermentation substrate from the main fermentation station with a flow rate of 15 kg of organic dry matter per each m ³ in the process container to be charged biomass volume never exceeds.

It is also characteristic of the technical solution according to the invention that, during the interrupted charging of the batchwise operated process container of a processing station, the one or more further process containers of this station are charged with the substrates from the upstream processing station.

It is possible to circulate the substrates in the process vessels of the batchwise operated processing stations in the methane fermentation plant operated according to the invention by the continuous or intermittent operation of stirring mechanisms and / or pumps.

• - Es können die an sich für den simultanen Fermentationsprozess unzureichend effizienten Rührbehälter genutzt werden.
• - In den einzelnen räumlich getrennten Bearbeitungsstationen stehen in zunehmendem Maße an die konkreten Anforderungen adaptierte Mikrokulturen zur Verfügung.
• - Eine gegenseitige Beeinträchtigung der Spezies der aktiven Mikrokulturen wird weitgehend ausgeschlossen.
• - Es können biogene Einsatzstoffe mit qualitativ unterschiedlichen Inhaltsstoffen mit hoher energetischer Wirksamkeit verwertet werden, weil die langsam wachsenden Keime für schwieriger abbaubare Inhaltsstoffe nicht durch schnell wachsende Keime für leicht abbaubaue Inhaltsstoffe verdrängt werden.
• - Es werden vergleichsweise hohe Umsetzungsraten der eingesetzten organischen Substanz zu Biogas erreicht, ohne dafür spezielle kulturerhaltende Fermentersysteme einsetzen zu müssen.
• - Die Fermentationsreste sind durch vergleichsweise hohe anorganische Anteile an der Trockensubstanz und damit durch hohe Konzentrationen an mineralischen Nährstoffen gekennzeichnet.
• - Es werden einfach zu dimensionierende Mindestbehandlungszeiten für die biogenen Einsatzstoffe gewährleistet.
• - Durch eine mögliche Mindesthandlungszeit von wenigstens 10 Tagen in der im thermophilen Milieu betriebenen Nachfermentationsstation wird bei Erfordernis ohne zusätzliche technische Einrichtungen die Vollstromhygienisierung der gewonnenen Fermentationsreste und damit der verfügbaren organischen NPKS-Düngemittel realisiert.
• - Der Energieaufwand für das thermische Hygienisieren der Gärsubstrate kann auch ohne aufwendigen Wärmetausch durch das Aufheizen der die Gärsubstrate aus der im mesophilen Milieu betriebene Hauptfermentationsstation von maximal 42 °C auf wenigstens 55 °C begrenzt werden.

The advantageous effects of the technical solution according to the invention can be summarized as follows:

• - It is possible to use the stirring vessels, which are in themselves insufficiently efficient for the simultaneous fermentation process.
• - In the individual spatially separate processing stations are increasingly adapted to the specific requirements adapted microcultures available.
• - Mutual impairment of the species of active microcultures is largely excluded.
• It is possible to utilize biogenic starting materials with qualitatively different ingredients with high energetic effectiveness, because the slowly growing germs for difficultly degradable ingredients are not displaced by rapidly growing germs for readily degradable ingredients.
• - It comparatively high conversion rates of the organic substance used to biogas can be achieved without having to use special culture-preserving fermenter systems.
• - The fermentation residues are characterized by comparatively high inorganic content of the dry matter and thus by high concentrations of mineral nutrients.
• - It is guaranteed easy to be dimensioned minimum treatment times for the biogenic materials.
• - By a minimum possible action time of at least 10 days in the operating in the thermophilic environment Nachfermentationsstation the full flow of the recovered fermentation residues and thus the available organic NPKS fertilizer is realized if required without additional technical facilities.
• - The energy required for the thermal sanitation of the fermentation substrates can be limited to at least 55 ° C even without extensive heat exchange by heating the fermentation substrates from the main fermentation station operated in the mesophilic milieu of maximum 42 ° C.

Embodiment:

The invention will be explained in more detail below with exemplary embodiments.

• 1 das Blockschaltbild einer Methanfermentationsanlage mit batchweise betriebener Nachfermentationsstation;
• 2 das Blockschaltbild einer Methanfermentationsanlage mit batchweise betriebener Haupt- und Nachfermentationsstation;
• 3 das Blockschaltbild einer Methanfermentationsanlage mit den batchweise betriebenen Bearbeitungsstationen Hydrolysestation, Hauptfermentationsstation und Nachfermentationsstation;
• 4 das Blockschaltbild einer Methanfermentationsanlage mit den batchweise betriebenen Hydrolyse- und Nachfermentationsstationen.

In the attached drawing show:

• 1 the block diagram of a methane fermentation plant with batchwise Nachfermentationsstation operated;
• 2 the block diagram of a methane fermentation plant with batchwise main and Nachfermentationsstation;
• 3 the block diagram of a methane fermentation plant with the batchwise operated processing stations Hydrolysestation, Hauptfermentationsstation and Nachfermentationsstation;
• 4 the block diagram of a methane fermentation plant with the batchwise operated hydrolysis and Nachfermentationsstationen.

Example 1:

According to the 1 a methane fermentation plant consists of a total of seven process vessels 14 of which, except for the preparation of the biosuspension from finely divided lignocellulosic biogenic feedstocks 2 in the form of 6,000 t of cattle manure per year, 1,000 t of mixed slurry solid phase and 13,000 m ^{3 of} biofiltrate 3 from the phase separation station 10 the digestate used Rühparparat 12 the suspension station 4 With a useful volume of 100 m ^3, all other containers are gas-tight.

Another stirred flow stirring device 13 with a useful volume of 300 m ³ is in the continuous process in the Hydrolysestation 6 used for the hydrolysis of the biosuspension produced. With a one-time pumping process, the flow-through stirring apparatus becomes 13 the hydrolysis station 6 loaded with the daily to be treated Biosuspension of 55 m ³ with a mean dry matter content of 15%. Previously, the hydrolysis station 6 each removed a corresponding amount of hydrolyzate and in the for the main fermentation station 7 used process container 14 pumped. That of the hydrolysis station 6 taken hydrolyzate was exposed on average 5.4 days and during a minimum treatment time of 1 day the aerobic hydrolysis conditions at an average of 50 ° C media temperature.

The main fermentation station 7 is used for fermentation in the mesophilic environment at an average temperature of 41 ° C.

For this purpose, a hydraulically miscible two-part container is used in plug flow operation. With a useful volume of 1,700 m ³ is in the main fermentation station 7 a minimum treatment time of at least 12 days.

When loading the main fermentation station 7 with the pumping station 5 for the obtained hydrolyzate is a corresponding amount of fermentation substrate from the process vessel 14 the main fermentation station 7 in the secondary fermentation station 8th repressed.

In the post fermentation station 8th become two fully mixable stirring devices 12 each of 1,000 m ³ useful volume used batchwise and in a thermophilic environment. While a completely filled stirrer 12 The entry of the fermentation substrate from the main fermentation station takes place daily for at least 10 days at regular time intervals for a maximum of 15 minutes 7 in the second process vessel 14 the post fermentation station 8th , In each case after the feed of the fermentation substrate in this process container 14 takes its mixing in the contained biomass of this container. Each before the upcoming complete filling of the second process container 14 becomes the first process container 14 the post fermentation station 8th taken from a quantity of about 550 m ³ digestate and by means of the fermentation residue pumping station 5 in the storage tank for the fermentation residues 9 used process container 14 rearranged. The in each case partially emptied container Nachfermentationsstation 8th Residual biomass residue is used in the subsequent re-feeding with fermentation substrate from the skin fermentation station 7 as the adapted culture containing vaccine. The useful volume of the storage tank for the fermentation residues 9 is also 1,000 m ³ . It primarily serves to decouple the fermentation and phase separation processes. The storage tank for the fermentation residues 9 The fermentation residue is taken with an average dry matter content of 11% and with the Gärrestdosierpumpenstation 5 the phase separation station 10 fed. There, the extraction of a dry matter-rich press cake with high levels of plant nutrients, which takes place in the fertilizer storage 11 is stored, and the low-dry biofiltrate 3 which is intermediately stacked in the biofilmattank. The Biofiltrattank serves to decouple the process stages phase separation station 10 and suspension station 4 and has a useful volume of 300 m ³ .

With daily about 35 m ³ biofiltrate 3 adapted portions of the microcultures for hydrolytic treatment contained therein and the mesophilic and thermophilic microculture for methane fermentation are attributed to the biotechnological process. By allowing the hydrolytic, mesophilic and thermophilic nuclei to become active in the spatially separate process stages under the respectively optimum conditions, the conversion rates of the organic substance used are significantly higher than in the prior art. In the example, biogas with an energy content of 10.9 GWh / a and a total of 2,650 t of organic dry matter annually becomes thus gained 4.1 kWh / kg of organic dry matter. This energetic degree of conversion is achieved, although for the immediate biotechnological treatment in the process stages hydrolysis 6 with 300 m ³ , the main fermentation station 7 with 1,700 m ³ and the secondary fermenter station 8th with a total of 2,000 m ³ only a useful volume of 4,000 m ³ for a daily amount of substrate from the suspending station 4 of 55 m ³ and is therefore available for only about 73 days of medium treatment time. Prerequisite for the compared with the biotechnological treatment by means of continuous flow stirred agitators 12 Considerably increased degree of conversion of the biogenic substance used is in addition to the biotechnological treatment taking place in the spatially separate treatment stages, each adapted to the treatment task micro-cultures treatment reached the minimum treatment time of 24 days, at multiples of the minimum treatment time of wet fermentation plants according to the prior art.

Example 2:

In Example 2, the biotechnological treatment according to the in 2 marked expiration. This differs from that of Example 1 essentially in that both the main fermentation stage 7 as well as the Nachfermentationsstufe 8th with batchwise stirred agitators 12 operate.

In Example 2, in the suspending station 4 from an annual use of 7,000 t rapeseed straw silage, 2,000 t mixed slurry solid phase as biogenic feedstock 2 and 18,350 m ³ biofiltrate 3 from the phase separation station 10 to treat the fermentation residues generated daily 75 m ^{3 of} biosuspension and the Hydrolysestation 6 fed.

The flow-through stirring device used for the hydrolytic treatment of the biosuspension 13 has a useful volume of 500 m ³ , whereby the semi-aerobic hydrolytic treatment can be carried out with a mean residence time of 6.6 days. The resulting hydrolyzates reach a pH of less than 5.5 in this treatment. The filling of the hydrolysis tank 13 displaced hydrolyzates pass alternately into the two batchwise operated stirred tank 12 the main fermentation station 7 , These process vessels 14 for methane fermentation in the mesophilic environment each have a useful volume of 1,200 m ³ . After complete filling of one of the two process vessels of the main fermentation station 7 this is circulated without further loading with hydrolyzate and without fermentation substrate removal over a period of 8 days by means of agitator technology so that there is no impairment of gas release due to a stabilizing floating layer. The between the main fermentation station 7 and the post-fermentation station 8th arranged pumping station 5 serves after the batchwise treatment of the hydrolyzate in the main fermentation station 7 for the transfer of about 560 m ^{3 of} fermentation substrate from the respective process vessel 14 the main fermentation station 7 in the previously partially emptied process container 14 the post fermentation station 8th , The two stirring devices 12 the post fermentation station 8th each have a useful volume of 1,500 m ³ . In front of an intended relocation process of 560 m ³ fermentation substrate from a process vessel 14 the main fermentation station 7 in the process container to be charged 14 the post fermentation station 8th This container is placed between the secondary fermentation station 8th and the storage tank for the fermentation residues 9 arranged pumping station 5 taken an amount of about 540 m ^{3 of} fermentation residue and placed in the storage tank 9 pumped. After re-filling this container with a basic inventory of adapted mesophilic microculture with fermentation substrate from the main fermentation station also operated in the mesophilic environment 7 the biotechnological treatment continues in the mesophilic milieu. By now largely lack of relatively easily degradable fatty acids, fats, proteins and carbohydrates in Nachfermentationsstation 8th fed fermentation substrate occurs in Nachfermentationsstation 8th to continue the microbial conversion of proportions of the supplied biogenic substance to biogas in the mesophilic environment.

However, a microculture is now available that has increasingly adapted to the requirements resulting from the predominant raw fiber nature of the organic dry matter contained in the fermentation substrate. Until the renewed rearrangement of fermentation substrate from the main fermentation station 7 pass again 8 days. Before the end of this treatment time, the second batch process vessel is operated 14 the post fermentation station 8th also removed a quantity of 540 m ³ fermentation residue and into the storage tank 9 promoted. Subsequently, the refilling of the receptive process container takes place 14 the Nachfermentationsstation with fermentation substrate from the main fermentation station 7 , As in Example 1, the fermentation residue produced is in the phase separation station 10 taken a dry matter and nutrient-rich fertilizer fraction with a flow rate of 17 t / d on average, while the resulting flow of biofiltrate 3 is fed to the container for the intermediate storage of Biofiltrates 50 t / d.

In the example, from a total of 3,620 tons of organic dry matter a year biogas with a Energy content of 16.4 GWh / a and thus 4.5 kWh / kg of organic dry matter won. This energetic degree of conversion is achieved, although for the immediate biotechnological treatment in the process stages hydrolysis 6 with 500 m ³ , the main fermentation station 7 with 2,400 m ³ and the secondary fermenter station 8th with 3,000 m ^3, only a useful volume of 5,900 m ³ for a daily amount of substrate from the suspending station of 75 m ³ and thus for only about 79 days of average treatment time is available. Prerequisite for the compared with the biotechnological treatment by means of continuous flow stirred agitators 12 Considerably increased degree of conversion of the biogenic substance used is in addition to the biotechnological treatment in the spatially separate treatment stages, each adapted to the treatment task micro-cultures treatment reached the minimum treatment time of 25 days, which is several times the minimum treatment time of wet fermentation plants according to the prior art.

Example 3:

The process variant explained in the present example differs from Example 2 according to FIG 3 primarily by the fact that the hydrolysis station 6 by the batchwise operation of two agitators 12 is marked.

In the example, 12,000 t of poultry manure, 1,500 t of mixed slurry solid phase and 25,500 m ^{3 of} biofiltrate are first used in the suspending station each year 4 39,000 m ³ Biosuspension produced with a total of 5,050 t of organic dry matter. For the aerobic hydrolytic treatment of the 107 m ^{3 of} biosuspension to be used daily, stand in the hydrolysis station 6 two stirring devices 12 each with a usable volume of 300 m ³ . During a process container 14 the hydrolysis station 6 107 m ^{3 of} hydrolyzate are removed on two consecutive days and fed to the main fermentation station, the second process container 14 the hydrolysis station 6 with the remaining starting culture of about 85 m ³ initially filled with 214 m ^{3 of} biosuspension and then hydrolytically treated for about two days. The amount of hydrolyzate taken daily from the hydrolysis station becomes the respective receptacle for the process 14 the main fermentation station 7 fed. The batchwise operated process vessels 14 the main fermentation station 7 each have a useful volume of 2,000 m ³ . The hydrolyzate in the completely filled process container 14 the main fermentation station 7 is treated in the mesophilic environment without further Hydrolyseatzufuhr and then as in Example 2 with an amount of about 800 m ³ in the Nachfermentationsstation 8th rearranged. The in each process container 14 Furthermore, the amount of fermentation substrate of about 1,200 m ^{3 contained} in the subsequent batch process serves as the seed mass containing the adapted mesophilic culture. Thereafter, this partially empty process container 14 Again with daily about 107 m ³ hydrolyzate charged while the previously charged process container 14 is only circulated until the upcoming refilling. The post fermentation station 8th is operated as in Example 2, but with two process vessels, each having a useful volume of 1,800 m ³ and each periodically only up to a residual amount of 1,040 m ³ in the storage container for the fermentation residues 9 be emptied. In the example, biogas with an energy content of 21.4 GWh / a and thus 4.2 kWh / kg of organic dry matter is obtained from a total of 5,050 t of organic dry matter per year. This energetic degree of conversion is achieved, although for the immediate biotechnological treatment in the process stages hydrolysis 6 with 600 m ³ , the main fermentation station 7 with 4,000 m ³ and the Nachfermentationsstation 8th with 3,600 m ^{3 in} total only a useful volume of 8,200 m ³ for a daily amount of substrate from the suspending station 4 of 107 m ³ and is thus available for only about 77 days mean treatment time.

Prerequisite for the compared with the biotechnological treatment by means of continuous flow stirred agitators 12 Considerably increased degree of conversion of the biogenic substance used is in addition to the biotechnological treatment taking place in the spatially separate treatment stages, each adapted to the treatment task micro-cultures treatment reached a minimum treatment time of 26 days, which is several times the minimum treatment time of wet fermentation plants according to the prior art.

Example 4:

In contrast to Example 3 are in the illustrated example according to the 4 only the hydrolysis step 6 and the post-fermentation station 8th with batchwise stirred agitators 12 fitted. In contrast, the biotechnological treatment takes place in the main fermentation stage 7 by means of a single culture-preserving and hydraulically partially mixed fermenter.

In the example, from annually 16,000 bagasse silage, sugar cane straw, 3,000 t Pressmud, 2,000 m ³ Vinasse and 49,500 m ³ biofiltrate 75,500 m ³ Biosuspension obtained with a potential of 9,900 t of organic dry matter. The hydrolysis station 6 is equipped with two batch-operated agitators with a useful volume of 800 m ³ each. In three-day rhythm, these process containers are reciprocal with each other 620 m ³ Biosuspension from the suspending station 4 charged and then treated aerobically hydrolytically. After a treatment period of at least two days, the process container which has been treated for the longest time becomes 14 taken daily about 205 m ^{3 of} hydrolyzate and into the process vessel 14 the main fermentation station 7 pumped with a useful volume of 8,000 m ³ . During the supply of hydrolyzate from the hydrolysis station 6 to the process container 14 the main fermentation station 7 Every day about 195 m ^{3 of} fermentation substrate in the receptive batchwise and in thermophilic milieu operated process vessel 14 the post fermentation station 8th discharged. The two process containers 14 the post fermentation station 8th have a usable volume of 4,000 m ³ each. After complete filling, the fermentation substrate in the respective process container 14 circulated periodically and at the earliest after 10 days to a residual inventory of contained biomass with the adapted microculture of least 2,000 m ³ discharged into the storage tank for the fermentation residues.

In each partially emptied process container 14 the post-fermentation station then becomes the fermentation substrate from the main fermentation station 7 entered.

In the example, biogas with an energy content of 42.1 GWh / a and thus 4.25 kWh / kg of organic dry matter is obtained from a total of 9,900 t of organic dry matter per year. This energetic degree of conversion is achieved, although for the immediate biotechnological treatment in the process stages hydrolysis 6 with 1,600 m ³ , the main fermentation station 7 with 8,000 m ³ and the Nachfermentationsstation 8th with 8000 m ^{3 in} total only a useful volume of 17,600 m ³ for a daily amount of substrate from the suspending station 4 of 207 m ³ and is therefore available for only about 85 days mean treatment time. Prerequisite for the compared with the biotechnological treatment by means of continuous flow stirred agitators 12 Considerably increased degree of conversion of the biogenic substance used is in addition to the biotechnological treatment in the spatially separate treatment stages, each adapted to the treatment task micro-cultures treatment reached the minimum treatment time of 25 days, which is several times the minimum treatment time of wet fermentation plants according to the prior art.

LIST OF REFERENCE NUMBERS

1 -

processing station

2 -

biogenic starting materials

3 -

Biofiltrat

4 -

Suspendierstation

5 -

pump station

6 -

hydrolysis station

7 -

Main fermentation station

8th -

Nachfermentationsstation

9 -

Storage tank for the fermentation residues

10 -

Phase separation station

11 -

fertilizer warehouse

12 -

agitator

13 -

Flow agitator

14 -

process vessels

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• DE 4446661 C1 [0002]
• EP 2242848 B1 [0005]
• DE 102011015415 A1 [0008]
• DE 102012005636 A1 [0009]

Claims (9)

Process for the batchwise use of fully mixable stirrers for methane fermentation in plants for biogas production from raw fiber-rich biogenic feedstocks, in separate stations producing a pumpable biosuspension from the finely divided feedstocks and the biofiltration obtained from the phase separation of the fermentation residues, the hydrolytic pretreatment of the biosuspension, the fermentation of the hydrolysates in the preferably mesophilic medium and the secondary fermentation of the fermentation substrates in a preferably thermophilic environment, characterized in that the batchwise biotechnological treatment in the respective processing station (1) is carried out in at least two process vessels (14) that the process vessels (14) the batchwise operated processing station (1) are equipped with special adapted to the substrates used microcultures that each with the substrate from the upstream Processing station (1) filled process container (14) of the batchwise operated processing station (1) is neither charged nor emptied for a period of between 5 and 15 days that at least the substrate treatment in the Nachfermentationsstation (8) is carried out batchwise and that the fermentation residues from Nachfermentationsstation (8) are stored in at least one storage tank (9) for the fermentation residues, Method according to the Claim 1 , characterized in that the respectively filled process container (14) of the main fermentation station (7) operated batchwise in the mesophilic milieu is neither charged nor emptied for at least 5 days. Method according to one of Claims 1 and 2 , characterized in that the respectively filled process container (14) of the post-fermentation station (8) operated batchwise in the thermophilic milieu is neither charged nor emptied for at least 10 days. Method according to one of Claims 1 to 3 , characterized in that during the batchwise substrate treatment with minimized use of mechanical stirring energy, the substrate re-circulation and the other process conditions are kept substantially constant. Method according to one of Claims 1 to 4 , characterized in that prior to refilling the batchwise operated process container (14), the substrate is emptied into the downstream processing station (1). Method according to one of Claims 1 to 5 , characterized in that the emptying of a batch-operated process container (14) except for a remaining substrate residue of at least 20%, preferably of at least 40%, of the nominal content of the respective process container (14). Method according to one of Claims 1 to 6 , characterized in that the daily loading of a partially emptied process container (14) of the batchwise operated processing station (1) with hydrolyzate from the Hydrolysestation (6) or fermentation substrate from the Hauptfermentationsstation (7) is carried out with a flow rate, which at any time 15 kg of organic dry matter each m ³ contained biomass volume in the process container to be charged (14) exceeds. Method according to one of Claims 1 to 7 , characterized in that during the interrupted loading of the batchwise operated process container (14) or the other process container (14) of the respective processing station (1) with the media of the respective upstream processing station (1) are charged. Method according to one of Claims 1 to 8th , characterized in that the substrates in the process containers (14) are circulated by continuous or intermittent operation of stirring mechanisms and / or pumps.

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