WO2022096048A1

WO2022096048A1 - Mobile biogas plant and method of operating the mobile biogas plant

Info

Publication number: WO2022096048A1
Application number: PCT/DE2021/000176
Authority: WO
Inventors: Hans-Joachim Auerbach
Original assignee: Auerbach Hans Joachim
Priority date: 2020-11-04
Filing date: 2021-10-28
Publication date: 2022-05-12
Also published as: EP4267715A1; CN116685673A; DE102020006788A1

Abstract

A mobile biogas plant and operation thereof, preferably also utilizable at sites lacking or with insufficiently developed communal infrastructure, is enabled by the combining of known measures for the achievement of maximum specific energy yields from the biogenic residue materials used and by the extreme reduction in the process energy demand required. This is possible in accordance with the invention by the combination of fermentation vessels for the anaerobic treatment of the suspended feedstocks either in a mesophilic or in a thermophilic medium, which are additionally in an arrangement with pressure-resistant gas spaces and partly one on top of another. It is thus possible to organise the conveying of the fermentation substrate largely without the customary use of pumps, utilizing naturally compressed process gases without using stirring mechanisms for substrate circulation in the process vessels for the anaerobic treatment and simultaneously for the transport of gas to the station for the energetic utilization of gas, as illustrated by figure 4.

Description

Mobile biogas plant and method for operating the mobile biogas plant

field of use

The invention relates to a mobile biogas plant for temporary or permanent operation at locations with limited or no municipal infrastructure for the ecologically safe utilization of biogenic residues, such as faecal sludge and/or biogenic household waste. Such a technical solution is required for the hygienic disposal and recycling of biogenic residues at locations with limited municipal infrastructure.

State of the art

The extraction of methane-containing fuel gases from biogenic material is considered an indispensable key technology in the field of so-called energy generation from regenerative sources. As a so-called all-rounder, it is superior to other techniques for using regenerative energy sources in particular in that it

- can be used for the supply of electrical and thermal energy as well as for the fuel supply,

- can be stored using tried and tested technical means that are available,

- can be used either for the energetic base load or for the peak load supply,

- can be combined with the production of particularly plant-available organic nitrogen-phosphorus-potassium-sulphur fertilizers,

- contributes to reducing the emission of harmful gases and

- can be used in a decentralized supply-effective way, at least in urbanized and/or industrialized regions, via already available and sufficiently powerful energy distribution networks.

Various technical solutions have already been made known as a prerequisite for the material and energetic utilization of available biogenic residual and waste materials at decentralized locations, preferably at locations with a missing or insufficient municipal infrastructure. DE 19721979C1 (1997) proposes the fermenter of a small biogas plant, which does not exceed the dimensions of a standardized transport container, contains all the accessories required for plant operation and is intended to enable the substrate to be circulated in the fermenter without mechanical stirring mechanisms by lateral rolling of the entire fermenter unit .

From the disclosure in DE 19846336A1 (1998) it can already be deduced that pretreated biogenic feedstock is hydrolyzed after mechanical pretreatment in a mechanically stirred percolator and the thin phase obtained after phase separation of the percolator output can be continuously fed to a methane fermenter as percolate. The residue from the methane fermenter then represents the so-called percolation water for the percolation upstream of the methane fermentation, which already contains the microculture adapted to the quality of the biogenic input materials.

A mobile biogas plant has already been described in DE 19958142 A1 (1999). This essentially consists of at least two system modules, which contain the necessary biotechnological or energy components separately from one another and are positioned in building shells with the dimensions of standard sea containers. The capacity requirements of plants with different recycling services are to be met by coupling the required number of modules, which are mostly prefabricated by the manufacturer.

DE 20104047U1 (2001) describes a bioreactor which meets the requirements of a mobile biogas plant to a limited extent, but is not suitable for particularly energetically efficient wet fermentation as it is used exclusively for so-called dry fermentation.

With the degradation method of biogenic material described in DE 102004053615B3 (2004), the previously described percolation method is further developed by the percolate from an aerobically operated percolator in is temporarily stored in one or more intermediate buffers and fed from there to control the output of the methane reactor as required. A mobile or semi-mobile biogas plant could also be configured in appropriately dimensioned tank sizes.

DE 2004062993A1 (2004) discloses the proposal for a biogas plant, which is characterized by a stationary mounted methane fermenter and by at least one mobile container unit with the additional technical equipment required for operating the plant.

DE 202005012340U1 (2005) proposes assembling the necessary components of a biogas plant not in standardized transport containers, but in likewise mobile or semi-mobile and specially designed prefabricated garages.

The technical solution for a biogas plant and for the production of biogas described in DE 102008015609A1 (2008) already contains the proposal for hydrolysis to take place upstream of the actual fermentation, which should preferably be spatially separated from the fermentation and carried out in batches in at least two hydrolysis tanks.

The proposal for a transportable and modular biogas plant disclosed in DE 102010000437U1 (2010) is that the performance-determining fermenter size is to be achieved by increasing the space by assembling transport containers that are standardized at the open ends.

EP 2781589B1 (2010) discloses a portable installation for obtaining renewable energy using one or more portable tanks, characterized by several first holding tanks for pasteurization and/or for fermentation in a thermophilic medium. Furthermore, a larger second holding tank is provided for the subsequent fermentation in the mesophilic environment.

3 A dewatering unit is also provided for the treatment of the fermentation residues occurring in the second holding tank, with the aid of which at least part of the fermentation residues can be obtained in dried form. By means of appropriate fluid connections and control devices, such a system design should be both portable and adaptable to the specific location requirements in a particularly advantageous manner.

A transportable biogas plant similar to the technical solution described above is explained in DE 102010044988A1 (2010). The fermenters should primarily be designed as containerized units that can be coupled with the basic equipment of the transportable biogas plant if there is a corresponding need for recycling.

WO 2013/088067A1 (2011) describes the variant of a modular biogas plant consisting of several transportable fermenters and a standardized line and control unit for coupling the fermenter modules, which means that easily variable plant sizes can be assembled.

A space-saving biogas plant with changing plant parameters is known from DE 202012007831U1 (2012). The fermenter modules that can be connected in large numbers to form a plant contain the associated ancillary equipment, preferably have a square floor plan and can be easily assembled to form plant configurations, with usable spaces for positioning further plant components being limited.

A central, modular pumping and crushing unit is described in DE 102013107621A1 (2013). Such a compact and transportable module is referred to there as a central component with pumps, valves, sensors and monitoring and control technology for the operation of a large number of different functional units of a biogas plant. DE 202013101554U1 (2013) contains a proposal for arranging process modules in a standardized size, preferably on a uniform level, with the delimiting walls of the modules at least partially supporting each other as a result of different installation variants and thereby enclosed spaces for other components of transportable and mobile biogas plants form.

DE 202014006483U1 (2014) describes a very simplified biogas plant that combines all the elementary functional components required in a standardized design. It should make it possible to promote the entry of biogenic input materials directly through the individual treatment rooms of the anaerobic treatment system to the discharge. In addition, it should also be possible to dispense with agitator circulation and the use of pumps.

CN 104140928 B (2014) describes a horizontal compact fermenter in tubular form with a longitudinal agitator, which can be transported with the dimensions of a transport container and can be used as the central unit of an anaerobic system in modular biogas plants.

Another technically relevant solution for the technical field of the invention can be found in CN 106281996 B (2015). For this purpose, a compact module is proposed in the dimensions of a standardized transport container, which allows for the crushing of the biogenic substances to be treated, the direct entry into the agitated horizontal fermenter, the direct discharge of the resulting biogas to hot flares or after raw gas treatment for energetic gas utilization, the heating of the Fermenter with the module for energetic gas utilization and the discharge of the fermentation residues from the horizontal fermenter.

WO2020180175A1 (2019) describes a technical solution that was primarily developed for municipal wastewater treatment. However, it contains important information for the anaerobic treatment in at least three spatially separated process vessels in which Use of mixed cultures that are active in different temperature ranges, in particular mesophilic and thermophilic mixed cultures, for the application of minimum treatment times of up to 21 days and for the targeted return of cultures adapted to the specific conditions of use. The explained analytical and mathematical effort for process monitoring and process control is understandable due to the changing wastewater qualities and at the same time the high demands on the required clean water quality.

With WO 2020/182684A1 (2019) a technical solution is made known which, in addition to a fermentation plant for the production of biogas, has both a process unit for the energetic utilization of a portion of the available biogas and a further process unit for the treatment of another partial flow of the biogas for the production of contains bio natural gas. For this purpose, the raw biogas obtained is first compressed. Using a gas separation unit, the compressed raw biogas is separated into a product gas with the quality of bio natural gas and a residual gas with a methane content of up to 20%. With the help of the residual gas, a process unit for energetic utilization of the residual gas is operated, with the help of which the energy supply for the compression unit can also be achieved.

The known state of the art thus provides technical solutions for the multi-stage biotechnological treatment of biogenic feedstocks in many variants, from which the following features can be taken in selected individual cases: a) The arrangement of the required system components should be possible on a fixed level. b) The dimensioning of the individual system components should not exceed the format of standardized transport containers. c) The system components should be capable of being prefabricated at the manufacturer's factory. d) The biotechnological treatment of the biogenic input materials should take place in several stages and in spatially separate process containers. e) The biogenic input materials to be utilized should be pre-comminuted, fluidized and suspended before the biotechnological treatment by means of wet fermentation. f) The biotechnological treatment is preferably carried out using hydrolytic, mesophilic and thermophilic environments and within a minimum treatment time of at least 20 days. g) Prismatic instead of cylindrical process containers serve to improve the utilization of the volumes of the transport containers. h) In order to prevent selected harmful germs from being smuggled through the biotechnological recycling plant, a sanitizing or sterilizing full flow treatment should be carried out. i) The fermentation residues should be made available for plant fertilization. j) Gas desulfurization should be carried out to avoid the emission of sulfur oxides during the utilization of the biogas obtained. k) The usable energy of the biogas obtained should at least correspond to the process energy requirements of the biotechnological recycling plant. 1) The emission of climate pollutants, such as methane and ammonia, should be avoided by using flare systems in the event of disruptions in the facilities for the energetic use of biogas.

A technical solution with which the elementary requirements mentioned above could be fully met has not yet been disclosed. This means that known technical solutions for the operation of a mobile or semi-mobile biogas plant at locations or in regions with no or insufficiently developed municipal infrastructure are not yet available. Either the necessary mobility of the system components to be used must be questioned because of the required minimum size of the system until a sufficient degree of energy self-sufficiency is achieved, or unacceptable environmental pollution would have to be accepted. object of the invention

The object of the invention is therefore to overcome the shortcomings of the known prior art. In particular, a technical solution is to be provided that can be used to set up mobile or semi-mobile biogas plants for the material and energetic utilization of selected biogenic municipal waste with different performance requirements. The technical solution to be developed should

- energy self-sufficient operation,

- the fulfillment of maximum requirements for water protection,

- the minimization of the emission of climate pollutants and

- the recovery of fermentation residues with a maximum

- enable specific content of mineral plant nutrients. In summary, the object of the invention is the development of a technical solution to meet the requirements specified below: m) Use of all known practical yield-promoting

Measures in a closed system as a prerequisite for the maximum practical development of the energy potential introduced with the biogenic input materials; n) Ensuring that all lines, apparatus and containers for media with a water pollutant potential for ground and surface water are fully double-walled; o) reduction of the required mechanical energy demand for the circulation of the fermentation media to minimize the process energy demand; p) Reduction of the required energy input for the promotion of the liquid and gaseous process media to minimize the process energy requirement.

Description of the invention

The object of the invention is solved by the features of claims 1 and 6. Advantageous configurations of the invention are characterized by the dependent claims. The advantages of the technical solution according to the invention compared to the prior art can be summarized as follows:

Within the meaning of this patent specification, a mobile biogas plant is to be considered a plant whose process components form transportable units with the maximum dimensions of standardized transport containers.

These process components are also characterized by the fact that they can be fully equipped at the factory. After the process components have been positioned on a prepared, level surface that can be driven on and after the components have been connected to the necessary process lines, the resulting plant for the biotechnological material and energetic utilization of biogenic input materials can be operated independently of infrastructural requirements.

The technical solution according to the invention has

- due to the complete elimination of mechanical media circulation in the anaerobically operated process vessels,

- because of the automatic transport of the fermentation substrates between the anaerobically operated process containers and

- Due to the possible renunciation of the use of mechanical means for gas transport, a minimal electrical process energy requirement.

- because of the waiver of the entry of the fermentation poison oxygen into the fermentation tank,

- because of the guarantee of the required minimum treatment times in the anaerobic environment,

- Because of the preservation of the microcultures adapted to the average quality of the biogenic input materials to be utilized through the use of culture-preserving fermenter technology in the main fermentation stage and the culture-preserving operation of fermentation tanks used in batch operation in the secondary fermentation stage and

- Due to the exclusion of mechanical shearing forces when circulating the fermentation substrate in the fermentation tanks, maximum specific biogas yields are achieved. The maximum degradation of the carbon introduced into the fermentation process with the biogenic input materials leads to a minimization of the proportion of organic matter in the dry matter of the fermentation residues, whereby the specific content of mineral plant nutrients in the fermentation residues is maximized.

The minimization of the electrical process energy requirement with simultaneous maximum specific biogas yield thus enables the smallest possible size of an energy self-sufficient biogas plant.

The lack of mechanisms for transporting the biogas produced, for circulating the fermentation substrates in the fermentation tanks and for transporting the fermentation substrates between the fermentation tanks allows maintenance and repair costs to be minimized when operating the mobile biogas plant according to the invention.

The biogas plant according to the invention does not require any additional biogas storage for the uninterrupted operation of a component for the energetic gas utilization, because a constant supply of gas can be guaranteed from the combined gas spaces of the anaerobically operated process containers. By adapting the performance of a combined heat and power plant for simultaneous electrical and thermal energy generation to the performance of the fermentation plant, the required process energy and, if necessary, excess amounts of energy are available for other tasks without interruption. The emission of water pollutants, which are considered to be the considerable ammonium content in the fermentation substrates, is ruled out by the 100% double wall of the mobile biogas plant on the absorption capacity of the outflow-free raised site area. The emission of gaseous climate pollutants is limited to the exhaust emissions of the gas engine and/or a gas boiler used.

The completely closed design of the interconnected process vessels safely prevents odor emissions as a prerequisite for the plant positioning in the vicinity of residential buildings. The need for additional operating materials for plant operation depends on the lubricant requirement of the gas engine used and on the provision of the filter masses for the operation of a chemical-physical gas desulfurizer to be provided in addition to the biological gas desulfurization.

In the case of temporary or permanent use of the mobile biogas plant in regions with an insufficiently developed municipal infrastructure, biotechnological technology for the material and energetic utilization of biogenic residues is provided, which meets the strictest requirements for environmental protection and sustainability. The operation of the mobile biogas plant makes a significant contribution to reducing the emission of harmful gases and water pollutants as a direct result of avoiding rotting and improper dumping of the treated biogenic residues.

The fermentation residues obtained are exposed to what is known as full-stream sanitation during batch fermentation in a thermophilic environment. As a result, the liquid and solid fermentation residues can be safely used as high-quality organic nitrogen-phosphorus-potash-sulphur fertilizers. This also makes important contributions to the organic production of plant-based food and feed.

The preferably thermally insulated transport containers are the prerequisites for unrestricted operation of the mobile biogas plant both in tropical regions and in regions with frosty periods.

example

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

Show in the attached drawing

1 shows the schematic representation of the linking of the required system components;

2 shows an exemplary arrangement of the necessary transportable system components on a site area;

3 shows the schematic representation of the valve-controlled transport of the non-gaseous process media through the individual process containers;

4 shows the schematic representation of the automatic transport of the biogas through the individual plant components; 5 shows the schematic representation of the automatic transport of the biogas in a mobile biogas plant with increased capacity;

6 shows the exemplary arrangement of the transportable plant components for a mobile biogas plant with increased capacity on a site area;

Example 1:

According to Fig. 1 to 4, a mobile biogas plant consists of the main components:

Site area 1 with a width of 8 m and a length of 18 m,

- pre-tank 2 with about 12 m ³ filling volume,

Process tank 3 for anaerobic treatment in a mesophilic environment with a filling volume of 80 m ³

2 process tanks 4 for anaerobic treatment in a thermophilic environment, each with a volume of 32 m ³ ,

Process tank 5 for the collection of the fermentation residues of a maximum of 55 m ³ and for the biological gas desulfurization 17 in the gas space of at least 10 m ³ ,

- a component for the system control 7,

- the surrounding raised edge 8 of the site area 1 with a height of at least 0.7 m,

- A station 9 for the energetic gas utilization, which is equipped with an additional gas desulfurization module 10, a combined heat and power plant 11 with an electrical output of 10 kW and a hot flare station 13 for a thermal output of 25 kW and a pump station 14.

The mobile biogas plant is to be used for the environmentally friendly and energy self-sufficient biotechnological recycling of faecal sludge that accumulates in mobile toilets. For this purpose, the smallest possible size was determined, which enables the energy self-sufficiency of the utilization plant when a maximum specific biogas yield is reached.

According to the technical solution according to the invention, the individual components are almost completely reduced to dimensions that do not exceed the dimensions of standardized transport containers. These transport containers are positioned and anchored on a drivable and watertight site area 1 . The preliminary container 2 is arranged in a horizontal 20-foot transport container with a usable volume of about 12 m ³ , which can be loaded by a container vehicle 15 .

The pump station 14 is also positioned in the same transport container so that it is protected from the weather. The tasks of the pump station 14 are reduced by the saving according to the invention of further transport requirements for liquid media: pumping the contents of the preliminary container 2 to obtain a homogenized biosuspension,

- on the dosed daily loading of the main fermenter 3 and on the loading of liquid organic NPKS fertilizers (nitrogen-phosphorus-potassium-sulphur fertilizers) from the collecting tank 5 for the sanitized fermentation residues into pick-up vehicles 15.

In addition to the pump station 14, the switching and control system 7 for the mobile biogas plant is also housed in this transport container.

As the main fermenter 3 for the anaerobic treatment of the biosuspension from the preliminary tank 2, a culture-preserving, hydraulically circulatable fermenter 3 according to the prior art is used, but with the dimensions of two interconnected transport containers with a usable filling volume of 80 m ³ . Experience has shown that the main fermenter 3 is operated with mesophilic mixed cultures that are sufficiently robust for the utilization of input materials with changing qualities.

The construction of the main fermenter 3 used has the special functions:

- that for the hydraulic circulation of the fermentation substrate, the only moving element that needs to be actuated is a mixing valve,

- that the constantly available hydrostatic pressure in the main fermenter 3 alone is sufficient for the simultaneous discharge of disruptive floating or sinking layers into the preliminary container 2, that the media flow through the areas of the main fermenter 3 takes place predominantly in plug flow, that the mixed culture adapted to the average quality of the biosuspension is maintained in a part of the fermenter construction 3 that can be dimensioned according to the requirements, that despite the use of a maximum gas pressure of +490 mbar, the construction can be operated over the period of the normal service life without regular pressure equipment revisions and

- That with the outflow pressure of the biogas produced from the main fermenter 3, in addition to the gas transport, other functions can be effected.

One of the features of the mobile biogas plant that is essential to the invention is the organization of the transport of the fermentation substrates between the anaerobically operated process containers 3, 4, 5. Only controlled valves 16 in the connecting lines are used for this purpose, the pneumatic drives of which only have a negligible energy requirement compared to pump delivery. 20 For this purpose, the higher component of the construction of the main fermenter 3 is positioned in a standing 40-foot transport container. At a height of at least 10.5 m above installation area 1, the fermentation substrate is discharged for further anaerobic treatment in post-fermentation station 4.

For the anaerobic treatment in the thermophilic milieu of post-fermenter station 4, there are two tanks in horizontal 20-foot transport containers that are operated in batches with a maximum filling volume of around 32 m ³ each. The post-fermenters 4 are positioned above the 40-foot transport container, which contains the process tank 5 for collecting the liquid fermentation residues with a maximum filling volume of 55 m ³ . With this container arrangement, after the discharge height of the fermentation substrate from the main fermenter 3 of +10.5 m, the maximum filling level in the secondary fermenters is at a maximum of +4.8 m above the floor of the site area 1. The minimum filling level that occurs when the secondary fermenter 4 is emptied can be reached is +2.8 m. Even 10 this height is still sufficient to handle the rearrangement of the fermentation residue from the post-fermenters 4 into the fermentation residue store 5 with a maximum fill level of +2.3 m with the hydrostatic pressure alone be able. Another special feature when using the technical solution according to the invention lies in the possible omission of the use of mechanical devices for the absolutely necessary circulation of the contents of the process containers 3, 4, 5. The available gas pressures in the individual process containers 3, 4, 5 are used for this purpose , which without exception are designed as statically solid constructions. While the gas spaces of the main fermenter 3 are designed for gas pressures of up to +490 mbar, the gas spaces of the post-fermenter 4 are designed for maximum gas pressures of 250 mbar and the gas space in collection tank 5 for the fermentation residues produced is designed for maximum gas pressures of 50 mbar. This enables the complete supply of the occurring process gases from the upstream areas of the anaerobic treatment system.

The amounts of biogas fed close to the ground into the process tanks of the post-fermentation station 4 and the digestate storage facility 5, while avoiding disturbing shearing forces through the tools of pumps and agitators, together with the gas quantities directly arising in the process tanks 4, 5, lead to media circulations such as those found in the digestion towers of modern sewage treatment plants for the Energetic utilization of excess biosludge from biological wastewater treatment can be successfully used with the help of technically compressed digester gases.

The digestate tank 5 sucks air quantities both for the purpose of reducing odor emissions from the atmospherically operated pre-tank 2 and for biological desulfurization of the biogases conducted through the anaerobically operated process tanks 3, 4 and introduced into the gas space of the process tank 5. In this way, the amounts of oxygen required for the aerobic mixed culture to reduce the hydrogen sulfide content of the biogas can be safely kept away from the methanogens active in the process containers 3, 4 as a fermentation poison. The largely desulfurized biogas is now available with an admission pressure of 30 to 50 mbar for the fine desulfurization 10, for the operation of the gas engine of a combined heat and power plant 11 or alternatively for the operation of a gas boiler 12 and a hot flare station 13. Experience has shown that no further increase in pressure of the supplied gas stream is necessary for this. The characteristic values assigned to example 1 are summarized in table 1:

Table 1: Characteristic values for example 1

The calculated need for process energy to be used under the conditions of continuous frost weather is shown in Table 2. Table 2: Calculated process energy requirement for example 1

Example 2:

According to FIGS. 1 to 4, a mobile biogas plant is designed as in example 1. In addition, however, the plant contains a device for crushing coarse parts in the biogenic residues used, a phase separation station 6 and a fixed storage area 18 for the intermediate stacking of solid organic NPKS fertilizers 19 as the solid phase of the fermentation residues treated with the aid of the phase separation station. In the exemplary plant, the biosuspension produced is comminuted by means of a Rotacut and the phase separation station is provided with a screw press separator. The required Rotacut is installed upstream of the pump station 14. The press screw separator of the phase separation station 6 is positioned above the preliminary container 2 in order to be able to feed the thin phase as a germ-containing biofiltrate directly to the preliminary container 2 and the solid phase of the fixed storage area 18 as solid organic fertilizer 19 without further transport costs.

The mobile biogas plant is to be used primarily for the environmentally friendly and energy self-sufficient biotechnological recycling of municipal kitchen waste and leftovers.

The characteristic values assigned to example 2 are summarized in table 3:

Table 3: Characteristic values for example 2

The calculated need for process energy to be used under the conditions of continuous frost weather is shown in Table 4.

Table 4: Calculated process energy requirement for example 2

Example 3:

According to FIGS. 5 and 6, a mobile biogas plant is designed according to the proposed technical solution. In contrast to the statements in the explained examples 1 and 2, in addition to two main fermenters 3 operated in parallel in regular operation for the anaerobic treatment of suspended biogenic municipal waste, a total of four batchwise and sequentially operated secondary fermenters 4 are connected downstream. The secondary fermenters 4 are used for the sanitizing anaerobic treatment of the fermentation substrates from the main fermenter station 3 in a thermophilic environment. The secondary fermenters 4 are positioned in standardized 20-foot transport containers and arranged upright above the process container 5 for collecting the fermentation residues from the secondary fermenters 4 . From the two main fermenters 3, each with a nominal volume of 80 m ³ , the resulting fermentation substrates flow at a discharge height of 10.5 m above the installation area 1 into the ready-to-receive of the four batch-wise operated secondary fermenters 4, each with a maximum filling volume of 25 m ³ , with the maximum fill level is around 8.0 m above installation area 1. In order to overcome the maximum hydrostatic load for the biogas quantities introduced into the process tanks 4, 5 near the ground, the biogas from the main fermenters 3 must be provided with an outflow pressure of between 900 and 950 mbar. After the filling levels in the post-fermenters 4 have been overcome, the biogases in the gas spaces of the post-fermenters 4 still have pressures of between 250 and 600 mbar. After these biogases have been used to circulate the fermentation residues in the collection tank 5, the partially desulfurized biogas is still available in the station for energetic gas utilization 9 at pressures of between 100 and 200 mbar. In this exemplary arrangement of the components of the mobile biogas plant, too, the transport of the liquid media between the anaerobically operated process containers 3, 4, 5 is made possible without exception by controlling the valves 16 in the connecting lines. The process gases with higher working pressures ensure that the respective container contents are circulated more effectively than in the basic variants, in which the use of pressure containers that require monitoring was dispensed with. The very compact arrangement of the process containers 3, 4, 5 that is made possible in this way also allows for higher energy yields from the biogenic residues used. However, the gas spaces of the fermentation tanks 3, 4 must meet the requirements for handling pressure equipment. Due to the multiple availability of the process containers 3, 4 in the respective anaerobic treatment stages, the pressure vessels, which have to be checked regularly, can be taken out of operation at the required times without having to completely interrupt the operation of the mobile biogas plant. The germ-containing biofiltrate from phase separation 6 is preferably used to suspend the biogenic municipal waste that is to be utilized materially and energetically. Therefore, in the example, the installation area 1 has been expanded to include the fixed storage area 18 for the temporary storage of the solid organic fertilizers 19 . The characteristic values assigned to example 3 are summarized in table 5:

Table 5: Characteristic values for example 3

The calculated need for process energy to be used under the conditions of continuous frost weather is shown in Table 6.

Table 6: Calculated process energy requirement for example 3

Reference List

1 - site area

2 - pre-tank

3 - process tank for anaerobic treatment in the mesophilic

milieu

4 - process tank for anaerobic treatment in the thermophilic

milieu

5 - process tank for the collection of the liquid

fermentation residues

6 - phase separation station for the fermentation residues

7 - plant control

8 - Upstand of the site area

9 - station for energetic gas utilization

10 - gas desulfurization module

11 - combined heat and power plant

12 - gas boiler

13 - Hot Flare Station

14 - pump station

15 - container vehicle

16 - valves in the connecting lines

17 - biological desulfurization of biogas

18 - fortified storage area

19 - solid organic fertilizers

Claims

patent claims

1. Mobile biogas plant for temporary or permanent operation at locations with limited or no communal infrastructure, containing

- a watertight vehicle-accessible site area (1); - Several system components with the maximum dimensions of standardized transport containers;

- at least five spatially separated process containers for the biotechnological treatment of the biogenic input materials to be utilized; - At least one preliminary container (2) for obtaining a through

Biosuspension produced by fluidization, crushing and mixing measures,

- at least three gas-tight process containers (3, 4) for the hydrolysis and/or for the anaerobic main fermentation in the mesophilic and/or in the thermophilic environment and/or for the post-fermentation in the mesophilic and/or thermophilic environment;

- At least one gas-tight process container (5) for the collection of the fermentation residues and the biological gas desulfurization;

- a phase separation station (6) for obtaining a biofiltrate with a reduced dry matter content compared to the liquid fermentation residues and

- a module for the system control (7), characterized in that

- that the gas-tight process containers (3, 4, 5) of successive treatment stages are arranged one above the other in such a way that the process container (3) for the first anaerobic treatment stage is in the uppermost position and the process containers (4, 5) for the subsequent anaerobic treatment stages are in lower positions positions are arranged;

- that the first process vessel (3) for the anaerobic treatment is a culture-preserving continuous flow fermenter;

- that the gas-tight process containers (3, 4, 5) are designed for gas pressures between 0.03 and 2.0 bar overpressure and

24 that at least two of the gas-tight process containers (4) can be used for the batchwise treatment.

2. Mobile biogas plant according to claim 1, characterized in that all of the transportable plant components are positioned on a drivable surface (1) with a peripheral raised edge (8) forming a collection space for the minimum content of the process container with the largest nominal volume.

3. Mobile biogas plant according to one of claims 1 and 2, characterized in that the station (9) for the energetic gas utilization consists of at least one post-desulphurization module (10), a combined heat and power plant (11) and/or a gas boiler (12) and a hot flare station ( 13) exists.

4. Mobile biogas plant according to one of Claims 1 to 3, characterized in that the process containers (2 to 5) arranged within the transport container preferably consist of flat, curved, profiled and/or ribbed container elements made of metal or plastic.

5. Mobile biogas plant according to one of claims 1 to 4, characterized in that a pump station (14) at least for feeding the first fermentation stage (3) with biosuspension, for feeding the phase separation station (6), for rearranging the fermentation residues or the obtained biofiltrates to the receiving container (2) and / or in collection vehicles (15) is available.

6. A method for operating a mobile biogas plant according to claim 1 with the process stages

- Production of a biosuspension from the fluidized and comminuted biogenic input materials and their homogeneous mixing with additional process liquids for the subsequent wet fermentation; First stage anaerobic treatment for methane fermentation in the mesophilic environment;

Second anaerobic treatment stage for batchwise methane fermentation in a thermophilic environment;

Collecting the liquid fermentation residues in an anaerobically operated collection tank,

Provision of the biologically desulfurized biogas for energetic utilization, characterized in that the fermentation substrates are transported between the process containers (3, 4, 5) of the individual anaerobic treatment stages by gravity, that the biogases obtained in the individual process stages (3, 4, 5). be passed through the process vessels of all subsequent anaerobic treatment stages. that the biogases are transported through the anaerobically operated process containers (3, 4, 5) and to the energetic gas utilization station (9) by means of their own pressure in the range between 0.03 and 2.5 bar overpressure, that the individual process containers (4, 5) biogas quantities supplied from the previously arranged treatment stages are used for additional substrate circulation and that the biogases flowing through the collection tank (5) for the liquid fermentation residues are at least partially biologically desulfurized there before being discharged to the station (9) for the energetic gas utilization. Method according to Claim 6, characterized in that at least the sludges occurring in the first anaerobic treatment stage (3) are returned to the pre-tank (2) by means of the hydrostatic pressure in the process tank (3) of the first anaerobic treatment stage.

8. The method according to any one of claims 6 and 7, characterized in that the rearrangement of the fermentation substrates between the anaerobically operated process vessels (3, 4, 5) is effected exclusively by controlling the valves (15) in the connecting lines (16). 9. The method according to any one of claims 6 to 8, characterized in that the dimensions of the process containers (3, 4, 5) are dimensioned for a minimum anaerobic treatment time of 20 days.

10. The method according to any one of claims 6 to 9, characterized in that the air for the biological desulfurization of biogas (17) in the anaerobically operated collection tank (5) for the liquid fermentation residues is taken from the preliminary container (2) for the production of the organic suspension.

27