WO2024251649A2 - Biogas installation fermenter vessel and method for operating same - Google Patents

Abstract

The invention relates to a biogas installation fermenter vessel (1), which has a vessel interior (3) which is formed by a bottom wall (4), a circumferential side wall (5) and a foil roof (6), connected in a gas-tight manner to the side wall (5), and in which a fermentable substrate is received. Also provided is a service device (2), which has a service platform in the form of a pedestal panel (8) which can be walked on, said service device being connected in a gas-tight manner to the side wall (5) and having a roof connection region (9) for a foil roof (6). The foil roof (6) is designed as a carrier air roof with a roof outer skin foil (20) and a gas accumulator foil (24). The pedestal panel (8) has a service opening (10) which can be closed in a gas-tight manner by means of a cover device (11) and through which a height-adjustable submersion device (17) can be moved out of and back into the vessel interior (3). According to the invention, a gas outlet (31; 37) connected to a gas extraction device is arranged above the plane of the pedestal panel (8) and/or above the plane of a vessel upper edge defined by the side-wall upper edge. It is proposed that alternatively or additionally, the pedestal panel (8) has an edge-side frame (19) projecting downwards into the vessel interior (3) and/or during operation of the biogas installation submerged in the substrate, said frame extending circumferentially on the edge side at least at the region of the pedestal panel (8) projecting into the vessel interior (3).

Description

Description

Biogas plant fermenter tanks and methods for operation

The invention relates to a biogas plant fermenter tank according to the preamble of claim 1 and a method for operating it according to the preamble of claim 22.

A biogas plant fermenter tank with a service device is known from EP 2 497 822 B1, with a tank interior that is formed by a bottom wall, a continuous side wall and a film roof connected to it in a gas-tight and, preferably detachable manner. A substantially liquid, fermentable substrate is accommodated in the tank interior up to a predeterminable fill level. The fermenter tank is equipped with a service device that has a service platform as a walkable, flat platform plate that is connected gas-tight to a tank side wall at the top on the one hand and has a roof connection area on the other hand to which the film roof is connected gas-tight. A service opening is provided in the platform plate, which can be closed in a gas-tight manner by means of a covering device and through which a diving device, in particular a submersible mixer and/or a feed pump of an injection device, which is height-adjustable on a guide mast, can be moved essentially gas-tight out of the fermenter tank and back into the fermenter tank for maintenance and service work.

In a fermenter tank with such a platform plate, it is generally known and common practice to discharge and extract the biogas produced directly via a gas extraction opening on the platform plate. This means that a relatively large distance is required between the underside of the platform plate and the filling level, so that on the one hand there is enough biogas available for discharge and extraction under the platform plate and on the other hand the Gas extraction opening would become blocked, particularly by substrate splashes, foam formation, etc. and removing a blockage and cleaning the pipe would only be possible with great effort. Obviously, due to the required relatively large distance of the filling level of at least about 60 cm, the otherwise possible higher filling height of the fermenter container with substrate cannot be utilized, so that the otherwise possible biogas production rate is disadvantageously reduced.

A further disadvantage is that if the cover device is removed without further measures, biogas would escape from the area under the platform plate to ensure a gas-tight opening of the service opening. In order to prevent gas from escaping, it is known from the above prior art to attach a rigid, pipe-like collar to the underside of the service opening in a gas-tight manner, which protrudes into the fermenter vessel interior with a length of at least approx. 60 cm below the substrate surface during operation and thus prevents a seal against gas escaping from the service opening when the cover is open. The disadvantage is that such a collar is complex to attach, often buckles due to the load from the substrate flow, which is expensive to repair, and slows down the substrate flow in its area in an unfavorable way. This means that when the siphon is activated, when the appropriate filling level is reached and especially when it is above this level, the collar is pushed into the pressure-free area of the shaft due to the excess gas pressure that is created by closing the gas extraction opening in the gas area, so that the collar protrudes into the area of the shaft to such an extent that the operation of the agitator is immediately impeded. The consequence is that the collar has to be removed.

The object of the invention is therefore to develop a biogas plant fermenter tank in such a way that the above disadvantages no longer occur and a further object of the invention is to propose a suitable method for operation.

The object of the invention is achieved with the features of the independent patent claims. Advantageous embodiments are the subject of the subclaims.

According to claim 1, a biogas plant fermenter tank is claimed with a tank interior which is defined by a bottom wall, a circumferential side wall and a film roof which is connected to the side wall in a gas-tight manner, preferably gas-tight and detachable, and in which a substantially liquid, fermentable substrate is accommodated up to a predeterminable fill level. The fermenter tank further comprises a service device which has a service platform as a walkable, preferably flat and/or horizontally aligned platform plate which is connected in a gas-tight manner to a tank side wall, preferably in an upper region as seen in the vertical axis direction, and further has a roof connection region to which the film roof is connected in a gas-tight manner, preferably gas-tight and detachable.

The platform plate has at least one service opening that can be closed gas-tight by means of a covering device and through which a diving device that is height-adjustable on a guide mast, in particular a submersible mixer and/or a feed pump of an injection device, can be moved essentially gas-tight out of the container interior and back into the container interior for maintenance and service work, wherein the film roof is designed as a supporting air roof with an outer roof skin film and a gas storage film arranged gas-tight under the outer roof skin film as a sub-roof film above the substrate level, as seen in the vertical axis direction. The outer roof skin film is preferably kept inflated in a predetermined roof shape, for example by means of a supporting air blower with a predetermined supporting pressure.

The gas storage foil forms a volume-variable gas storage tank in which the biogas produced is collected and can be expanded towards the outer roof skin foil depending on the gas filling volume.

Furthermore, the fermenter vessel comprises a gas extraction device, by means of which the gas collected in the gas storage can be discharged and/or withdrawn from the vessel interior via a gas outlet opening into the gas storage, for example by means of a conveying device, such as a pump.

In addition, at least one vertical support is provided in the fermenter vessel, which is aligned in the vertical axis direction, preferably at least one vertical central support arranged approximately centrally and/or centrally in the vessel interior, which, preferably starting from the bottom wall, with an upper head part, relative to the vertical axis direction, protruding above a maximum substrate level, wherein the upper head part, preferably the upper end of the upper head part seen in the vertical axis direction, is designed as a belt carrying and belt connecting part, from which a plurality of support belts are stretched above the substrate level to the side wall regions, on which the gas storage film lies when the gas storage is not or only slightly filled with gas, preferably without dipping into the substrate.

According to a first aspect of the invention, it is provided that the gas outlet connected to the gas extraction device, preferably by means of at least one gas line of the gas extraction device, is arranged, viewed in the vertical axis direction, above the plane of the platform plate and/or above the plane of a container upper edge defined by the side wall upper edge.

This advantageously means that the gas outlet or gas extraction opening from the gas storage unit is always above the substrate level, thus enabling reliable gas removal that is not at risk of permanent blockage even when the container is fully filled, i.e. when the substrate level is at the level of the platform plate and/or the level of the top edge of the container. Since the gas extraction does not take place at the platform plate, no gas volume is required under the platform plate, so that the substrate level can be higher up to the platform plate, which means that the fermenter volume can be better utilized due to the larger substrate volume. In addition, raising the substrate level in this way advantageously eliminates the critical collar that protrudes downwards at the service opening.

In a first specific embodiment of the invention, it can be provided that the support itself or a component arranged in the region of the support, preferably directly or indirectly coupled to the support, has or forms the gas outlet opening into the gas storage in the region of the upper head part, preferably in such a way that the gas outlet is connected by means of at least one gas line of the gas extraction device, by means of which the gas collected in the gas storage is guided in the direction of the bottom wall and can be extracted from the fermenter container. In a specific embodiment that is particularly easy to manufacture, functionally integrated and therefore particularly preferred, the support extending from the base wall can be tubular and form a gas line of the gas extraction device leading to the base wall, which is led out of the area of the fermenter container on the base wall side, preferably below the base wall and/or in the base wall, either by itself or coupled to at least one other gas line of the gas extraction device. In this embodiment variant, the gas outlet is then advantageously formed with little component-intensiveness by an inflow opening formed on the upper head part of the support.

Alternatively or in addition to such a gas line in a support tube, at least one gas line of the gas extraction device can be arranged on the side of the support, preferably connected to it, which has an inflow opening forming the gas outlet and is led to the bottom wall, where it is led out of the area of the fermenter container on the bottom wall side, preferably below the bottom wall and/or in the bottom wall, either by itself or coupled with at least one other gas line of the gas extraction device. Even if they involve additional component expenditure, such designs can be implemented quickly and easily from a technical perspective and are therefore particularly suitable in connection with retrofitting existing systems.

It is practical to arrange a protective hood at a distance and, as seen in the vertical axis direction, above the respective inflow opening provided. This serves in particular as protection against the inflow opening being covered by a lowered gas storage foil of a gas storage tank that is not or only slightly filled and/or to ensure that the gas in the area below the spaced protective hood flows unhindered into the associated gas line via the inflow opening.

In the case of a downward-directed gas discharge, the formation of condensate cannot be excluded or there may be a need for flushing and therefore the gas extraction device can optionally have a cleaning and/or maintenance device in the area outside the fermenter container, in particular for separating condensate and/or for flushing the at least one gas line of the gas extraction device, which The extracted gas can be fed in via the gas line leading from the fermenter tank. In concrete terms, for example, a condensate pipe can be attached to the bottom of the support pipe, which drains condensate under the bottom wall via a siphon into a collecting tank. Slightly above the lower end of the support, dewatered biogas can also be fed in via a side connection to the support pipe as a gas extraction opening and led out of the tank area at the side.

Alternatively or in addition to the lower gas outlet on the floor wall side, an equally advantageous upper gas outlet can also be provided, in which the gas storage film has or forms the gas outlet opening into the gas storage, preferably in such a way that the gas outlet is connected to the gas extraction device by means of at least one roof-side gas line, by means of which the gas collected in the gas storage is guided in the direction of the roof outer skin film and can be withdrawn from the fermenter container, preferably in the area of the roof outer skin film. Particularly preferably, a roof-side gas line can be provided here, which forms the gas outlet with a lower mouth end in relation to the vertical axis direction and is connected to the gas storage film, preferably above the upper head part and/or in a gas-tight manner, as seen in the vertical axis direction. Furthermore, it is then provided that the roof-side gas line has or forms a primary line section that extends at least in part in the vertical axis direction upwards towards the roof outer skin foil, preferably extending to the highest point or the dome tip of the roof outer skin foil. And here again there are several options for ensuring effective gas extraction starting from the primary line section:

Thus, the primary line section with an upper mouth end, relative to the vertical axis direction, for forwarding the biogas outside the fermenter tank, can be connected, preferably gas-tight, to a roof opening in the roof outer skin film, preferably in the area of the dome tip of the roof outer skin film, to which in turn another gas line is connected as a secondary line section for forwarding the biogas outside the fermenter tank. Alternatively, it can also be provided that the primary line section penetrates the outer roof skin foil, preferably in a gas-tight manner, and is continued with a secondary line section outside the fermenter tank.

As a further alternative, it can be provided that a further gas line is connected to the primary line section, preferably in the region of the dome tip, as a secondary line section, which is guided as an internal gas line, preferably along the inside of the gas outer skin film downwards towards the upper edge of the container and out of the fermenter container, preferably up to the upper edge of the container and there through the roof outer skin film out of the fermenter container.

The connection of the roof-side gas line to the gas storage foil moves up and down depending on the filling level of the gas storage. The connected roof-side gas line should be able to follow this gas volume-dependent movement of the gas storage foil with as little force as possible and without restoring forces. For this reason, it can be provided that the roof-side gas line can move with the gas storage foil, preferably essentially without restoring forces, whereby it is preferably provided that the roof-side gas line is designed like a bellows and/or with support rings spaced apart in the longitudinal direction of the roof-side gas line.

Furthermore, an embodiment is also advantageous in which - alternatively or in addition to the possibilities described above - it is provided that the platform plate has a mounting wall that projects upwards in the vertical axis direction and extends in the area above the plane of the platform plate and above the upper edge of the container, wherein the mounting wall, preferably an upper edge area of the mounting wall in the vertical axis direction, forms at least part of the roof connection area, to which at least a partial area of the gas storage film is connected, so that the mounting wall adjoins the gas storage. It is also provided that the mounting wall has or forms the gas outlet that opens into the gas storage, preferably in such a way that the gas outlet is connected by means of at least one gas line of the gas extraction device, by means of which the gas collected in the gas storage can be extracted from the fermenter container. With such an embodiment, the initially mentioned mentioned advantages, whereby the mounting wall can also be used in an advantageous dual function for the arrangement of further components.

It is also advantageous if the fermenter tank has an injection device which has at least one feed pump by means of which injection liquid can be sucked out, preferably from the substrate of the fermenter tank or from another fermenter tank of the biogas plant, wherein the injection device has at least one injection nozzle element which is fluidly connected to the at least one feed pump and by means of which the injection liquid sucked out by means of the at least one feed pump can be injected into the fermenter tank in such a way that, based on the vertical axis direction, it hits the surface of a floating layer of the substrate from above as a liquid jet and wets it. This ensures that these floating layers can participate in the fermentation process even without being stirred into the substrate. Due to the jagged surface structure of the floating layer, the bacteria in the liquid jet also find a sufficient attack surface for an effective fermentation process with a high biogas yield.

And in connection with such an injection device, it is now particularly advantageous if the injection nozzle element is also held on the mounting wall, preferably held and guided through it.

The above features and measures can be implemented advantageously and expediently in conjunction with a cylindrical fermenter container, which is why it is preferably provided that the fermenter container has a cylindrical circumferential side wall with a support forming a central support in the cylinder axis. In principle, however, other container shapes are also possible.

According to a second aspect of the invention, alternatively or in addition to the first aspect of the invention, it is provided that the platform plate has an edge frame which projects downwards into the interior of the container and/or dips into the substrate during operation of the biogas plant and which runs around the edge at least on the area of the platform plate which projects into the interior of the container. It is ensured in a particularly simple and reliable manner that gas tightness is still ensured even when the service opening is open and the substrate level is just below the level of the platform plate, with the substrate level in the fermenter tank also still being set high. This advantageously uses the entire contents of the fermenter tank up to the foil roof connection for substrate filling and the associated biogas production, and ensures gas tightness when the service opening is open. In addition, such a frame also contributes to the advantageous stiffening and stabilization of a platform plate, which can then also be made relatively thin. Accordingly, the edge frame is preferably designed as a rigid, inflexible frame, preferably made of metal. For example, it can only protrude about 5 cm to 20 cm downwards from the platform plate.

In addition, the edge frame can conveniently run around the edge of the area of the platform plate that protrudes into the interior of the container and then connect directly to the side wall, possibly also connecting it in a gas-tight manner. Alternatively, the edge frame could also be provided - at least in sections - in the area of the platform plate that adjoins the side wall, for example in order to form a corresponding stop on the side wall.

The platform plate can advantageously be designed as a stable metal or stainless steel plate, for example relatively thin with a thickness of, for example, 3 to 5 cm.

Specifically, the covering device which closes the service opening in a gas-tight manner can be formed by at least one cover and/or by a mast housing which projects upwards away from the service opening and forms a receiving space for a mast upper part of the guide mast.

In a preferred embodiment, the platform plate is trapezoidal, preferably isosceles trapezoidal, wherein the longer trapezoid base side is connected gas-tight to the top of the container side wall and the platform plate is supported downwards towards the inside of the housing wall by means of at least one platform plate support. Furthermore, a method for operating a biogas plant fermenter tank according to one of the above features is claimed in such a way that during biogas plant operation, but at least during the time when the service opening is open, the level of the substrate in the fermenter tank is set so high that the platform plate is at least partially immersed in the substrate on the edge, optionally with an edge frame. This advantageously uses the entire content of the fermenter tank up to the foil roof connection for substrate filling and the associated biogas production, and ensures gas tightness when the service opening is open.

Using a drawing, examples of biogas plant fermenter containers according to the invention with a service facility are explained.

They show:

Fig. 1 shows an example of a section through a biogas plant fermenter tank with a service device and with a gas extraction point in the middle downwards through a tubular support,

Fig. 2 a section through a biogas plant fermenter tank with a service facility with a biogas extraction in the middle upwards over a foil roof,

Fig. 3 the biogas plant fermenter tank according to Figure 2 with a more heavily filled gas storage tank,

Fig. 4 a top view of a platform plate of the service facility without

foil roof,

Fig. 5 a section along the line A-A through an edge area of the

Platform plate according to Figure 4, and Fig. 6 shows a further exemplary embodiment with a mounting wall of the platform plate extending in the area above the plane of the platform plate and above the upper edge of the container, on which the gas outlet opening into the gas storage tank is formed.

Figure 1 shows an example of a section through a biogas plant fermenter tank 1 with an example of a service device 2 with a tank interior 3 formed by a bottom wall 4, a circumferential side wall 5 in a cylindrical shape and a film roof 6 connected to it in a gas-tight manner. During plant operation, liquid, fermentable substrate 7 is essentially filled in up to the height of the side wall 5.

The service facility 2 has a service platform as a walkable, preferably flat platform plate 8, as shown in detail in Figure 4 with its lateral gas-tight connection to the side wall 5. Opposite this is a roof connection area 9 to which the foil roof 6 is connected in a gas-tight manner. In the area of the service facility 2, the otherwise dome-like foil roof is indented and, for the sake of clarity, is not shown in this area in Figure 1.

As can be clearly seen from Figure 4, the platform plate 8 has a large rectangular service opening 10, which can be closed gas-tight using a cover device 11 as shown in Figure 1. The cover device 11 here comprises, by way of example, only a cover 12 and a portion of a mast housing 13 which projects upwards above the platform plate 8 and forms a receiving space for the upper part of a guide mast 14 which is pivotably mounted on the base wall 4 in a pivot bearing 15. A submersible mixer 17 is held on the guide mast 14 in a height-adjustable manner by means of a cable winch 16, for example. When the cover is open, the submersible mixer 17 can be lifted out through the service opening 10 above the platform plate 8 for maintenance and service work, as shown by way of example in Figure 2.

The platform plate 8 is designed here as a relatively thin metal or stainless steel plate with a thickness of approx. 5 cm and has an approximately isosceles trapezoidal shape, with the longer trapezoidal base side at the top of the Container side wall 5 is connected in a gas-tight manner. In addition, the platform plate 8 is supported towards the inside of the housing with platform plate supports 18 (shown only schematically). As can be seen in particular from the sectional view according to Figure 5, the platform plate 8 has a frame 19 on the edge that projects downwards into the container interior and into the substrate, which frame is designed here as a rigid and inflexible frame.

The edge frame 19 is preferably connected to the underside of the platform plate.

In addition, the edge frame 19 here only runs around the edge of the area of the platform plate 8 that protrudes into the interior of the container and is directly connected to the side wall 5, possibly also in a gas-tight manner. Alternatively, the edge frame 19 can also be provided - at least in sections - in the area of the platform plate 8 that adjoins the side wall 5, for example in order to form a corresponding stop on the side wall 5.

The foil roof 6 is designed as a supported air roof with a roof outer skin foil 20, which blows air 22 with a predetermined supporting pressure into an air space 23 under the roof outer skin foil 20 by means of a supporting air blower 21, whereby the roof outer skin foil 20 is kept inflated in a dome-like roof shape.

Under the roof outer skin foil 20 and under the air space 23 there is a gas storage foil 24 arranged gas-tight at the edge, which forms a gas storage 25 with a variable volume above the substrate level 26, into which the biogas 27 generated flows. Depending on the filling level of the gas storage 25, the gas storage foil 24 is expanded more or less upwards towards the roof outer skin. As an example, the gas storage foil is shown in dashed lines with reference number 24a in a lower area with a low gas filling level.

In the fermenter tank 1, a stable support 28 is arranged centrally and vertically, here as a central support, which has an upper head part 29 projecting above the substrate level 26. A plurality of support belts 30 extend from the upper end of this head part 29 and are radiating above the substrate level to the The gas storage foil 24 is stretched towards the side wall 5, onto which the gas storage foil 24 rests when the gas storage 25 is not filled with gas or only slightly, and thus does not dip into the substrate 7.

The gas extraction and gas removal from the gas storage 25 takes place here through a gas line of a gas extraction device, in this case, for example, in the middle and viewed in the vertical axis direction from top to bottom, in such a way that the support 28 is used as a gas line pipe and is designed with an inlet opening 31 as a gas outlet, which is covered from above by a spaced protective hood 32 against a closure by a gas storage film 24 that has sunk downwards and under which the biogas 27 can flow into the inlet opening 31 (arrows 33). From the upper inlet opening 31 of the support 28, the biogas 27 is guided downwards to the base wall 4 and from there with another gas line 34, for example under the base wall 4, to outside the fermenter area for further use. Instead of the support 28 or in addition to it, a gas line could also run downwards along it, which could then be conveniently connected to the support 28.

In the gas line used here from top to bottom (seen in the vertical axis direction) through the area of the substrate 7, condensate formation cannot be ruled out, so that a drainage device 35 is provided schematically and by way of example outside the fermenter container 1 as a cleaning and/or maintenance device. Condensed water is collected here in a collecting container 36.

As can be seen from Figure 1, the filling level 39 with substrate 7 during plant operation corresponds to the side wall height, whereby the entire possible filling level of the fermenter tank is utilized. The substrate level 26 is directly at the height of the platform plate 8, with the frame 19 dipping slightly into the substrate 7, but to such an extent that no biogas escapes there when the service opening 10 is open.

Figure 2 shows a biogas plant fermenter 1 which largely corresponds to the biogas plant fermenter tank from Figure 1, so that the same parts are designated with the same reference numerals. In particular, the basic structure and the service device 2 are the same. The embodiment according to Figure 2 differs, however, with regard to the gas extraction from the gas storage 25:

In contrast to Figure 1, the gas extraction of biogas takes place here in the middle upwards, with a gas line 40 in the form of a bellows 41 with variable length being used above the support area. The gas line 40 forms a primary line section here, which here, for example, extends upwards in the vertical axis direction to the highest point or dome tip 44 of the roof outer skin film 20. Biogas 27 thus flows from below into the gas line 40, the lower mouth end 37 of which forms the gas outlet, while the upper mouth end of which is here, for example, gas-tightly connected to an opening in the roof outer skin film 20 and from there is passed on with another gas line 42 as a secondary line section for further use. Alternatively, the gas line 40 and the gas line 42 can also be formed by a single gas line, which then penetrates the roof outer skin film 20 in the region of the dome tip 44 of the roof outer skin film 20, preferably in a gas-tight manner.

As an alternative to this, this further gas line 42, as shown only in dashed lines and extremely schematically in Figure 2, can also be connected to the gas line 40 forming the primary line section in the region of the dome tip 44 and can be led as an internal gas line along the inside of the gas outer skin film 20 downwards to the upper edge of the container 45 and from there through the roof outer skin film 20 out of the fermenter container 1.

It is essential here that the gas line 40 or the primary line section can be varied in its length without major restoring forces, since the connection area 43 to the gas storage film 24 changes in its height depending on the filling level of the gas storage 25. To support this, additional support rings 53 spaced apart from one another can be provided on the bellows 41.

The gas line 40 preferably has a relatively large diameter.

In Figure 3, the biogas plant fermenter tank 1 of Figure 2 is shown again, but with a significantly more filled gas storage 25, whereby the Connection area 43 is located significantly higher and closer to the outer roof skin film 20 compared to Figure 2. As a result, the gas line 40 is clearly shortened and pushed together as bellows 41 compared to the state according to Figure 2.

Figure 6 shows a further exemplary embodiment in which the platform plate 8 has a mounting wall 46 which projects upwards in the vertical axis direction and extends in the region above the plane of the platform plate 8 and above the upper edge 45 of the container.

An upper edge region 47 of the mounting wall 46 in the vertical axis direction forms part of the roof connection region 9, to which a partial region of the gas storage film 24 is connected, so that the mounting wall 46 adjoins the gas storage 25.

The mounting wall 46 here forms the gas outlet 54 opening into the gas storage 25, preferably in such a way that the gas outlet 54 is connected by means of at least one gas line 55 of the gas extraction device, by means of which the gas collected in the gas storage 25 can be extracted from the fermenter container 1.

Furthermore, an injection device 48 is provided, which has a feed pump 49, by means of which injection liquid can be sucked out, here for example from the substrate 7 of the fermenter container 1, as is shown here only schematically by the arrow 50.

The injection device 48 here further comprises an injection nozzle element 51 which is fluidly connected to the feed pump 49 and by means of which the injection liquid sucked out by means of the feed pump 49 can be injected into the fermenter container 1 in such a way that, with respect to the vertical axis direction, it strikes the surface of a floating layer 52 of the substrate 7 from above as a liquid jet and wets it.

As can be further seen from Figure 6, the injection nozzle element 51 is also held on the mounting wall 46, preferably held and guided through it. Overall, all of the preferred embodiments shown here in the description of the figures are characterized in that the gas outlet, viewed in the vertical axis direction, is always arranged above the level of the platform plate 8 and/or above the level of a container upper edge 45 defined by the side wall upper edge of the side wall 5, which means that a functionally reliable discharge of the gas is possible, which is not permanently at risk of clogging even with a fully filled container, i.e. a substrate level at the level of the platform plate 8 and/or the level of the container upper edge 45.

list of reference symbols

1 biogas plant fermenter tank 25 gas storage tanks

2 Service facility 26 Substrate level

3 Container interior 27 Biogas

4 floor wall 28 support

5 side wall 29 headboard

6 foil roof 30 support straps

7 Substrate 31 Inlet opening

8 Platform plate 32 Protective cover

9 Roof connection area 33 arrow

10 Service opening 34 Gas line

11 Covering device 35 Drainage device

12 lids 36 collection containers

13 Mast housing 37 lower muzzle end

14 Guide mast 38 Connection area

15 Pivot bearing 39 Filling level

16 cable winch 40 gas line

17 Submersible mixer 41 Bellows

18 Platform support 42 Gas pipe

19 Frame 43 Connection area

20 Roof outer skin foil 44 Dome tip

21 Supporting air blower 45 Container top edge

22 Air 46 Mounting wall

23 Airspace 47 Upper edge area

24 Gas storage foil 48 Injection device

49 Feed pump 53 Support rings

50 Arrow 54 Gas outlet

51 Injection nozzle element 55 Gas line

52 floating layer

Claims

patent claims 1 . Biogas plant fermenter tank, with a tank interior (3) which is formed by a bottom wall (4), a surrounding side wall (5) and a foil roof (6) connected to the side wall (5) in a gas-tight, preferably gas-tight and detachable manner, and in which a substantially liquid, fermentable substrate is accommodated up to a predeterminable fill level, with a service device (2) which has a service platform as a walkable, preferably flat and/or substantially horizontally aligned platform plate (8), which is connected in a gas-tight manner to the side wall (5), preferably to an upper region as seen in the vertical axis direction, and further has a roof connection region (9) to which the foil roof (6) is connected in a gas-tight, preferably gas-tight and detachable manner, wherein the platform plate (8) has at least one service opening (10) which can be closed in a gas-tight manner by means of a cover device (11) and through which a height-adjustable Diving device (17), in particular a submersible motor mixer and/or a feed pump of an injection device, can be moved essentially gas-tight out of the container interior (3) and back into the container interior (3) for maintenance and service work, wherein the film roof (6) is designed as a supported air roof with a roof outer skin film (20) and a gas storage film (24) arranged gas-tight under the roof outer skin film (20) as a sub-roof film above the substrate level (26), viewed in the vertical axis direction, wherein the gas storage film (24) forms a volume-variable gas storage in which generated biogas collects and can be expanded towards the roof outer skin film (20) depending on the gas filling volume, with a gas extraction device, by means of which the gas collected in the gas reservoir (25) can be discharged and/or withdrawn from the container interior (3) via a gas outlet (31; 37; 54) opening into the gas reservoir (25), with at least one vertical support (28) aligned in the vertical axis direction in the fermenter container (1), preferably at least one vertical central support arranged approximately centrally and/or centrally in the container interior (3), which, preferably starting from the bottom wall (4), projects with an upper head part (29) relative to the vertical axis direction above a maximum substrate level, wherein the upper head part (29), preferably the upper end of the upper head part (29) viewed in the vertical axis direction, is designed as a belt carrying and belt connecting part, from which a plurality of support belts (30) are stretched above the substrate level to the side wall areas, onto which the gas storage film (24) rests in the event of no or little gas filling of the gas storage device, characterized in that the gas outlet (31; 37; 54) connected to the gas extraction device, preferably by means of at least one gas line (34; 40) of the gas extraction device, is arranged, viewed in the vertical axis direction, above the plane of the platform plate (8) and/or above the plane of a container upper edge (54) defined by the side wall upper edge, and/or that the platform plate (8) has an edge-side frame (19) which projects downwards into the container interior (3) and/or dips into the substrate during operation of the biogas plant and which runs around the edge at least on the region of the platform plate (8) which projects into the container interior (3). 2. Biogas plant fermenter tank according to claim 1, characterized in that the support (28) itself or a component arranged in the region of the support (28), preferably directly or indirectly coupled to the support (28), has or forms the gas outlet (31; 37; 54) opening into the gas storage (25) in the region of the upper head part, preferably in such a way that the gas outlet (31; 37; 54) is connected by means of at least one gas line (34; 40; 55) of the Gas extraction device is connected, by means of which the gas collected in the gas storage (25) is guided towards the bottom wall (4) and can be extracted from the fermenter container (1). 3. Biogas plant fermenter tank according to claim 2, characterized in that the support (28) extending from the bottom wall (4) is tubular and forms a gas line (34) of the gas extraction device leading to the bottom wall (4), which gas line is led out of the region of the fermenter tank (1) on the bottom wall side, preferably below the bottom wall (4) and/or in the bottom wall (4), itself or coupled to at least one further gas line of the gas extraction device, that the gas outlet is formed by an inflow opening (31) formed on the upper head part of the support. 4. Biogas plant fermenter tank according to claim 2 or 3, characterized in that at least one gas line of the gas extraction device is arranged laterally on the support (28), preferably connected thereto, which has an inflow opening forming the gas outlet and is led to the bottom wall, where it is led out of the region of the fermenter tank on its own or coupled with at least one further gas line of the gas extraction device on the bottom wall side, preferably below the bottom wall and/or in the bottom wall. 5 Biogas plant fermenter tank according to one of claims 2 to 4, characterized in that a protective hood (32) is arranged at a distance and, viewed in the vertical axis direction, above the inflow opening (31), in particular as protection against covering the inflow opening (31) by a lowered gas storage film (24) of a gas storage that is not or only slightly filled and/or so that the gas in the area below the spaced protective hood (32) flows unhindered via the inflow opening (31) into the associated gas line. 6. Biogas plant fermenter tank according to one of the preceding claims, characterized in that the gas extraction device in the area outside the fermenter tank (1) has a cleaning and/or maintenance device (35), in particular for separating condensate water and/or for flushing the at least one gas line of the gas extraction device, to which the gas extracted from the fermenter tank (1) can be fed by means of the gas line (34) leading from the fermenter tank (1). 7. Biogas plant fermenter tank according to one of the preceding claims, characterized in that the gas storage film (24) has or forms the gas outlet opening into the gas storage (25), preferably in such a way that the gas outlet is connected by means of at least one roof-side gas line (40) of the gas extraction device, by means of which the gas collected in the gas storage (25) is guided in the direction of the roof outer skin film (20) and, preferably in the region of the roof outer skin film (20), can be withdrawn from the fermenter tank (1). 8. Biogas plant fermenter tank according to claim 7, characterized in that the roof-side gas line (40) forms the gas outlet with a lower mouth end (37) in relation to the vertical axis direction and is connected to the gas storage film (24), preferably above the upper head part (29) and/or gas-tight as seen in the vertical axis direction, and that the roof-side gas line (40) has or forms a primary line section which extends at least partially in the vertical axis direction upwards in the direction of the roof outer skin film (20), preferably extending to the highest point or to the dome tip (44) of the roof outer skin film (20). 9. Biogas plant fermenter tank according to claim 8, characterized in that the primary line section is connected with an upper mouth end, based on the vertical axis direction, preferably gas-tight, to a roof opening in the roof outer skin film (20), preferably in the region of the dome tip (44) of the roof outer skin film (20), to which in turn a further gas line (42) is connected as a secondary line section for a Forwarding of the biogas is connected outside the fermenter tank or that the primary line section penetrates the outer roof skin film (20), preferably gas-tight, and is continued with a secondary line section outside the fermenter tank (1). 10. Biogas plant fermenter tank according to claim 8, characterized in that the primary line section, preferably in the region of the dome tip (44), is followed by a further gas line (42) as a secondary line section, which is guided as an internal gas line, preferably along the inside of the gas outer skin film (20) downwards towards the upper edge of the tank and out of the fermenter tank, preferably up to the upper edge of the tank and there through the roof outer skin film (20) out of the fermenter tank (1). 11. Biogas plant fermenter tank according to claim 8 to 10, characterized in that the roof-side gas line (40) can be moved together with the gas storage film (24), preferably essentially without resetting, wherein it is preferably provided that the roof-side gas line (40) is designed like a bellows and/or with supports (53) spaced apart in the longitudinal direction of the roof-side gas line (40). 12. Biogas plant fermenter tank according to one of the preceding claims, characterized in that the platform plate (8) has a mounting wall (46) which projects upwards in the vertical axis direction and extends in the area above the plane of the platform plate (8) and above the upper edge of the container (45), that the mounting wall (46), preferably an upper edge area of the mounting wall (46) in the vertical axis direction, forms at least part of the roof connection area (9), to which at least a partial area of the gas storage film (24) is connected, so that the mounting wall (46) adjoins the gas storage (25), that the mounting wall (46) has or forms the gas outlet (54) opening into the gas storage (25), preferably in such a way that the gas outlet (54) is connected by means of at least one gas line (55) of the Gas extraction device is connected, by means of which the gas collected in the gas storage (25) can be extracted from the fermenter container (1). 13. Biogas plant fermenter tank according to one of the preceding claims, characterized in that an injection device (48) is provided, that the injection device (48) has at least one feed pump (49) by means of which injection liquid can be sucked out, preferably from the substrate of the fermenter tank (1) or from another fermenter tank of the biogas plant, that the injection device (48) has at least one injection nozzle element (51) fluidly connected to the at least one feed pump (49), by means of which the injection liquid sucked out by means of the at least one feed pump (49) can be injected into the fermenter tank (1) in such a way that, based on the vertical axis direction, it strikes the surface of a floating layer (52) of the substrate (7) from above as a liquid jet and wets it. 14. Biogas plant fermenter tank according to claim 12 and 13, characterized in that the injection nozzle element (51) is held on the mounting wall (46), preferably held and guided through it. 15. Biogas plant fermenter tank according to one of the preceding claims, characterized in that the fermenter tank (1) has a cylindrically circumferential side wall (5) with a support (28) forming a central support in the cylinder axis. 16. Biogas plant fermenter tank according to one of the preceding claims, characterized in that the edge frame (19) only runs around the edge of the area of the platform plate (8) protruding into the tank interior (3) and connects directly, preferably gas-tight, to the side wall (5). 17. Biogas plant fermenter tank according to one of the preceding claims, characterized in that the platform plate (8) is formed by a metal plate, in particular by a stainless steel plate. 18. Biogas plant fermenter tank according to one of the preceding claims, characterized in that the edge frame (19) of the platform plate (8) projecting downwards into the container interior (3) is connected to the underside of the platform plate (8). 19. Biogas plant fermenter tank according to one of the preceding claims, characterized in that the edge frame (19) is designed as a rigid frame, preferably made of metal and/or projects downwards from the platform plate by approximately 5 cm to 20 cm. 20. Biogas plant fermenter tank according to one of the preceding claims, characterized in that the cover device (11) closing the service opening (10) in a gas-tight manner is formed by at least one cover (12) and/or by a mast housing (13) projecting upwards away from the service opening (12) and forming a receiving space for a mast upper part of the guide mast (14). 21. Biogas plant fermenter tank according to one of the preceding claims, characterized in that the platform plate (8) is trapezoidal, preferably isosceles trapezoidal, and that the longer trapezoid base side is connected gas-tight at the top to the side wall (5) and the platform plate (8) is supported downwards towards the container interior (3) by means of at least one platform plate support (18). 22. Method for operating a biogas plant fermenter tank according to one of the preceding claims, characterized in that during the biogas plant operation, but at least during the time when the service opening (10) is open, the filling level of the substrate in the fermenter tank (1) is set so high that the platform plate (8) is at least partially immersed in the substrate on the edge, optionally with an edge frame (19).