Gassing device for a mixing device, and mixing device

Abstract

The invention relates to a method (100) for producing biogas, said method (100) having the steps of: - cultivating (101) microorganisms in a container (201), said microorganisms comprising facultative anaerobes and obligate anaerobes, and - introducing (103) an oxygen-containing gas stream into the container, the gas stream of oxygen introduced into the container (201) being regulated spatially, temporally and / or quantitatively on the basis of at least one measured value, which is determined by means of at least one sensor (203) provided on the container (201), in such a way that the facultative anaerobes metabolize aerobically and the obligate anaerobes survive such that the biogas yield is maximized.

Description

[0001] "Method and apparatus for producing biogas

[0002] Description:

[0003] The presented invention relates to a method and a biogas plant for producing biogas, according to the attached claims.

[0004] Biogas plants use microorganisms to produce biogas, such as methane. The biogas synthesis process is known to essentially comprise four steps:

[0005] - In hydrolysis, the organic polymers are first split into monomers.

[0006] - This is followed by acidogenesis, in which short-chain fatty acids (volatile organic acids (FOS), alcohols, amino acids and water are formed from the monomers.

[0007] - In the subsequent acetogenesis, the metabolic products formed in acidogenesis are broken down into acetic acid and water.

[0008] During these process steps, carbon dioxide, hydrogen, and trace gases such as ammonia and hydrogen sulfide can also be formed. Hydrolysis, acidogenesis, and acetogenesis can each be carried out, at least partially, by anaerobic and / or aerobic metabolism.

[0009] The subsequent fourth process step, methanogenesis, involves the formation of a biogas mixture, specifically comprising methane and carbon dioxide. Methanogenesis requires anaerobic metabolism, whereby the anaerobes involved produce the desired methane from acetic acid, hydrogen, and carbon dioxide.

[0010] Without significant spatial separation, the described biogas synthesis processes are implemented simultaneously in the known biogas plants.

[0011] It is also known that facultative anaerobes can use oxygen available in the fermentation substrate to switch from an anaerobic metabolism to an aerobic metabolism.

[0012] Aerobic metabolism is more energy-efficient than purely anaerobic metabolism because more energy can be provided for the organism.

[0013] This significantly accelerates the biological processes in a biogas plant, particularly through the formation of enzymes required for the rapid breakdown of a substrate. Furthermore, aerobic metabolism allows the breakdown of substrates that would be indigestible through purely anaerobic metabolism.

[0014] Furthermore, it is known that facultative anaerobes can be cultivated in a symbiotic relationship with strict anaerobes for efficient biogas production.

[0015] Strict or obligate anaerobes can have their metabolism inhibited by even the smallest amounts of oxygen; in some cases, this can lead to their death. Experience has shown that the tolerance threshold of obligate anaerobes lies between 0.5 and 2% oxygen by volume, and sometimes even lower. High oxygen levels can therefore reduce the biogas yield of a biogas plant, as methane-synthesizing anaerobes are comparatively oxygen-intolerant.

[0016] It is therefore an object of the presented invention to maximize biogas yield during the operation of a biogas plant or to improve biogas quality. Biogas yield can be measured as the amount of gas in cubic meters per unit of time. It is also possible to express the biogas yield as the amount of gas in cubic meters relative to the weight of the fresh mass or the organic mass of the supplied substrate. Biogas quality can refer to the proportion (in volume percent) of methane in the biogas. For example, the power output of a combined heat and power plant (heat quantity, electrical energy) can be used as an indicator of the amount of methane produced, especially when the biogas quality is known.

[0017] Thus, according to a first aspect of the presented invention, a method for producing biogas is presented.

[0018] The presented method for producing biogas involves cultivating microorganisms in a container, wherein the microorganisms include facultative anaerobes and obligate anaerobes.

[0019] Furthermore, the presented method comprises introducing an oxygen-containing gas stream into the container, preferably a continuous introduction, wherein the gas stream of oxygen introduced into the container is spatially, temporally and / or quantitatively controlled as a function of at least one measured value, which is determined by means of at least one sensor arranged on the container, such that the facultative anaerobes operate in an aerobic metabolism and the obligate anaerobes survive, in such a way that the biogas yield, and preferably also the biogas quality, is maximized.The survival of the obligate anaerobes is indicated by a particularly sustained maximization of the biogas yield, for example essentially over half the conversion time, preferably essentially over the entire conversion time of an introduced amount of substrate, since the metabolism of the obligate anaerobes or the efficiency of the methane conversion is not significantly impaired by the intended addition of oxygen.

[0020] In contrast to unintended process disturbances, which can cause a short-term increase in biogas but are subsequently regularly accompanied by a sharp decrease in the quantity or quality of biogas, the invention is based on the idea of ​​increasing the overall output in the longer term, i.e., maximizing both the quantity and quality of biogas.

[0021] In other words, a targeted spatial, temporal and quantitative addition or injection of oxygen into the container enables at least a partially aerobic operation of the biogas plant, so that processes such as hydrolysis, acidogenesis and acetogenesis can be increased, which surprisingly does not reduce, but rather increases the biogas yield.

[0022] The presented method is based on a control system, specifically a closed-loop control system, in which the amount of oxygen introduced into the container is regulated, i.e., dynamically increased or decreased, over time and / or space. For this purpose, the state of microorganisms cultivated in the container is monitored by means of at least one sensor, and the measured values ​​obtained by the sensor are used to adjust or regulate the amount of oxygen introduced into the container. One or more measured values ​​can be acquired and used to control the oxygen addition.

[0023] According to a further training, it can be provided that a number of values ​​are assigned to a state from a multitude of states by means of a machine learner, and preferably that the oxygen-containing gas flow is controlled when an assigned state deviates from a predetermined target state.

[0024] The control system can be configured to assign measured values ​​for at least one quantity, determined by at least one sensor, to a state from a plurality of states using a machine learner. If the assigned state deviates from a predetermined target state, a predefined setting is preferably applied, particularly regarding oxygen control, to the assigned state. A given state can be characterized, in particular, by physical properties, especially optical properties, and / or chemical properties, preferably by biogas quantity and / or biogas quality. For this purpose, it can be provided that a state is specified by a numerical value, which is, for example, calculated from a number of values.

[0025] To create the key figure, for example, a value can be assigned to a number of quantities according to a predefined assignment scheme, or a numerical value of the key figure can be assigned to each.

[0026] The allocation scheme can, for example, include a multitude of weighting factors that weight the influence of respective variables on the key figure. Accordingly, such a key figure represents a given state, particularly quantitatively. Specifically, the key figure condenses several variables into a single numerical value, allowing a complex state encompassing many characteristics to be quickly and easily captured using the key figure.

[0027] Based on values ​​of quantities determined by the number of sensors, oxygen control, in particular the introduction, can preferably be carried out so that the facultative anaerobes work in an aerobic metabolism and the obligate anaerobes survive, preferably induced by maximizing the biogas quantity and / or the biogas quality.

[0028] A machine learner, such as a trained artificial neural network, which assigns values ​​to a first or second class, or a first or second state, based on a given fundamental truth, can quickly and reliably detect deviations from a target state. Preferably, the values ​​quantify the biogas yield or quantity and / or biogas quality, preferably based on a number of parameters according to the lists described below, which can be recorded by means of a number of sensors.In other words, the machine learner enables the individual recognition of a number of parameters to identify the quantity and / or quality of biogas, whereby it may be intended that constant factors, such as components of a biogas plant, are also recognized or taken into account in order to avoid misinterpretations of the intended regulations.

[0029] In the context of the invention, a number can refer to a singular or a plurality of a corresponding feature.

[0030] For further training, a mathematical evaluation of a number of values ​​may be required, depending on which the proposed regulation may be preferentially applied:

[0031] ■ First, a number of values ​​are determined by capturing a number of quantities using a number of sensors, preferably to describe a number of states.

[0032] ■ Preferably, a number of sensors determine a multitude of values ​​for a preferably quantitative and / or qualitative characterization of a number of states. ■ For at least one state, it is deduced whether the state is unintended, whether there is a need for action, and / or what action options exist.

[0033] ■ If action is required, for example if the condition suggests an insufficient quantity and / or quality of biogas, the introduction of the oxygen-containing gas flow can be regulated to influence the condition in a targeted manner.

[0034] The presented method dynamically adjusts the amount of oxygen introduced into the container in such a way that the facultative anaerobes operate in aerobic metabolism and the obligate anaerobes survive or are cultivated in an atmosphere tolerated by the obligate anaerobes.

[0035] The oxygen is preferably added to the contents of the container or to the fermentation substrate containing the microorganisms, whereby one or more injection points or injection areas may be provided. Advantageously, a spatially controlled oxygen addition can be combined with a temporally and quantitatively controlled addition of oxygen, so that, on the one hand, aerobic zones with the aforementioned advantages can be provided locally, and on the other hand, zones can be created in which the obligate anaerobes can work undisturbed.

[0036] Accordingly, it may be provided in particular that the at least one sensor detects at least one vital parameter of the microorganisms, in particular a first vital parameter of the facultative anaerobes and a second vital parameter of the obligate anaerobes.

[0037] By adjusting the oxygen introduced into the container according to the invention as a function of a measured value determined by the at least one sensor, a fixed amount of oxygen in the container can be avoided and instead an environment adapted to the respective current needs of the microorganisms can be provided.

[0038] Compared to known methods, the present proposal enables a significant increase in efficiency by providing oxygen-containing gas to the microorganisms essentially continuously and / or in a modulated manner, i.e., adapted or demand-oriented, particularly with the support of a machine learner. Predicted values, which can be calculated by a machine learner, can preferably be taken into account for the modulation, and based on these predicted values, the oxygen-containing gas flow can be adjusted, preferably taking into account a number of other parameters.

[0039] The invention is based on the idea of ​​keeping the environmental conditions for the microorganisms as constant as possible. This avoids the need for the microorganisms to constantly switch their metabolism between anaerobic and aerobic states. In known processes, these metabolic shifts lead to a loss of productivity, i.e., a reduced quantity and / or quality of biogas, since these transition periods cannot be used for biogas production. Given the large number of microorganisms, this situation is associated with significant economies of scale, such that avoiding these metabolic shifts results in a disproportionate increase in the quantity and / or quality of biogas.

[0040] In particular, the presented method adapts the oxygen introduced into the container to a specific oxygen requirement of the microorganisms, so that a change in the microorganism culture, e.g. due to a change in the container contents or by adding oxygen, leads to an adjustment of the oxygen introduced into the container with regard to spatial, temporal and / or quantitative resolution.

[0041] By dynamically adjusting the oxygen introduced into the container, preferably continuously, an atmosphere or environment is created in which the facultative anaerobes operate in an aerobic metabolic state and which is tolerated by the obligate anaerobes. This maximizes the amount of biogas produced by the microorganisms. Limit values ​​for a tolerable oxygen concentration for obligate anaerobes can be, in particular, 0.5–2 vol% or less.

[0042] It may be provided that at least one parameter from the following list of parameters is detected at least temporarily, preferably continuously, by means of the at least one sensor: oxygen concentration in a biogas produced by the microorganisms, oxygen concentration in a container containing the microorganisms, partial pressure of oxygen in the biogas, partial pressure of oxygen in the container contents, electrochemical properties, spectral properties.

[0043] Preferably, for the sake of a particularly simple design, it may be provided that an oxygen-related parameter is only measured at one point.

[0044] By measuring the partial pressure of oxygen, e.g., in the container contents, it is preferable to derive information about the physiology and availability of oxygen to the microorganisms. In particular, the total amount of available oxygen can be assessed by measuring the oxygen concentration.

[0045] In particular, the partial pressure of oxygen in a container containing microorganisms provides information about whether and within what time period a quantity of oxygen introduced into the container is completely converted by the facultative anaerobes, and consequently, whether damage to the obligate anaerobes is prevented.

[0046] Accordingly, it can be provided that if the partial pressure of oxygen in a container containing microorganisms increases after a plateau phase and / or exceeds a predetermined threshold, the amount of oxygen introduced into the container is reduced, in particular until the oxygen concentration in the container falls, e.g., below the predetermined threshold. In particular, the oxygen concentration in biogas produced by the microorganisms can preferably be used to derive the oxygen consumption of the microorganisms, taking into account the amount of oxygen added.

[0047] Similarly, it can be provided that at least one parameter from the following list of parameters is detected at least temporarily, preferably continuously, by means of the at least one sensor: CO2 or H2 partial pressure and / or CO2 or H2 concentration in the container contents and / or in the product gas or in the biogas.

[0048] It may further be provided that at least one sensor is used to detect at least one parameter from the following list in biogas produced by microorganisms and / or in a container containing microorganisms: methane concentration, hydrogen concentration, carbon dioxide concentration, hydrogen sulfide concentration, ammonium concentration, ammonia concentration, biogas quantity, residual biogas potential, biological activity, population of at least one type of microorganism, process parameters, dry matter (DM), organic dry matter (oDM), free organic acids (FOS), total inorganic carbon (TAC), ratio of free acids to buffer capacity (FOS / TAC), pH value, electrical conductivity (EC), redox potential, acid profile, flow properties, viscosity, container temperature.A decrease in total solids (TS) or organic total solids (oTS) content with a substantially constant addition of fermentation substrate to the tank can indicate increased degradation activity. Inorganic carbon can be present, for example, in the form of lime, which can exert a buffering effect in the tank. A change, particularly a decrease, in the FOS / TAC ratio or the FOS content with a substantially constant addition of fermentation substrate to the tank can indicate increased conversion of organic acids and thus higher biological activity. Furthermore, the pH value can change due to a change in the biological process, i.e., the metabolic activity of the microorganisms. For example, if more FOS is metabolized, acid reduction can be indicated by a rising pH value. Additionally, salts are known to influence electrical conductivity.Increased biological activity can lead to an increased binding of salts in cells, resulting in a measurable decrease in electrical conductivity. Conversely, increased electrical conductivity can be measured when increased amounts of salts are released through cell death, for example, when microorganisms die due to unfavorable environmental conditions.

[0049] For the present proposal, in particular at least one sensor can be provided which detects a size from the previously described lists online, i.e. preferably directly in the container contents.

[0050] Directly within the container contents or the fermentation substrate, the measurement of a gas partial pressure or gas concentration can be carried out, particularly preferably optically and / or electrochemically / galvanically, preferably using a Clark electrode or similar sensor technology, for example, to detect oxygen, carbon dioxide, hydrogen, and / or methane. This sensor technology is particularly advantageous due to its immediate proximity to the biological processes within the container, as changes can be detected without significant latency, allowing for rapid responses. In one embodiment, the detection of oxygen, carbon dioxide, hydrogen, methane, and / or hydrogen sulfide can be carried out directly within the biogas.

[0051] It may also be provided that at least one sensor is used to detect at least one quantity within a specified time range after the oxygen-containing gas stream has been introduced into the container.

[0052] By measuring at least one parameter after the (intermittent) introduction of an oxygen-containing gas stream, the effect of the gas stream on the microorganisms can be evaluated. For this purpose, the oxygen-containing gas stream can, for example, be introduced into the container in a cyclical process for a predetermined duration or with a predetermined amount of oxygen, and at least one parameter can be measured after this time.

[0053] A substantially continuous introduction of an oxygen-containing gas stream is particularly preferred. By comparing a measured value with another measured value, e.g., with a value determined in a previous cycle, and / or with a modulated value, deviations in the measured quantity between different cycles can be determined. Depending on this deviation, the amount of oxygen used in a subsequent cycle can be adjusted, e.g., relative to the deviation or increased or decreased by a predetermined amount. Such control allows the amount of oxygen to be regulated so that the measured quantity is kept substantially constant or is continuously increased or decreased.

[0054] It may also be provided that the amount of oxygen is regulated by adjusting a mass flow rate of the oxygen-containing gas stream, adjusting an oxygen concentration of the oxygen-containing gas stream, selectively controlling injection valves of a large number of injection valves to introduce the oxygen-containing gas stream into the container and / or adjusting the activity of an agitator to mix the container contents containing the microorganisms.

[0055] In particular, by selectively controlling a large number of injection valves to introduce the oxygen-containing gas stream into the container, a local adjustment of the substrate used for cultivating microorganisms can be achieved, thus compensating for, for example, local concentration differences of the respective microorganisms. This can be accomplished, for instance, by using a suitably distributed arrangement of several sensors within the container.

[0056] It may also be provided that the introduction of the oxygen-containing gas flow is reduced and / or stopped if at least one value determined by the at least one sensor is greater than or equal to a predetermined limit value.

[0057] By reducing and / or stopping the introduction of the oxygen-containing gas flow when at least one value determined by the at least one sensor is greater than or equal to a predetermined limit, damage to the obligate anaerobes due to an excessively high oxygen concentration is prevented. The predetermined limit can be selected based on an oxygen concentration tolerated by the obligate anaerobes. In particular, stopping the introduction of the oxygen-containing gas flow can be performed in addition to the regulation provided for in the invention, so that the regulation cannot escalate into an impermissible range or a range not tolerated by the obligate anaerobes.

[0058] Furthermore, if a deviation between a measured value and a target value exceeds a predefined alarm threshold and / or lasts longer than a predefined alarm duration, a warning message can preferably be displayed on an output unit reporting the deviation. To report the deviation or alarm status, the warning message can, for example, be sent to the output unit, which might, for instance, display a

[0059] The display and / or storage can be transmitted so that a user and / or a control function can detect the warning message and initiate appropriate countermeasures.

[0060] Advantageously, multiple sensors can determine measured values ​​along the oxygen-containing gas stream.

[0061] The path of the oxygen-containing gas flow, in particular the gas flow through the container contents or through the fermentation substrate, is referred to here as the effective path. It is particularly advantageous for one or more sensors to determine one or more measured values ​​along the effective path in order to derive the effect of the oxygen on the microorganisms with preferably high spatial and temporal resolution.

[0062] A long effective range is advantageous for efficient oxygen utilization and, preferably, for acquiring numerous measurements. The effective range can be extended, for example, by injecting the oxygen as deeply as possible, preferably at the bottom of the container, so that the oxygen can rise from bottom to top through the fermentation substrate. Furthermore, the effective range can be extended by circulating the fermentation substrate, for example, by means of an agitator arranged in the container. Against this background, the control loop according to the invention, or the proposed controlled introduction of the oxygen-containing gas flow, can preferably comprise a targeted spatial, temporal, and / or quantitative addition of oxygen along the effective range.

[0063] A suitably homogeneous distribution and sufficient availability of oxygen for the microorganisms can preferably be achieved by introducing the oxygen-containing gas stream, particularly the oxygen, as fine bubbles. In this context, "fine bubbles" refers to gas bubbles generated by nozzles, each nozzle outlet having a diameter of less than or equal to 100 pm, preferably less than or equal to 10 pm, and particularly preferably less than or equal to 1 pm. A nozzle can be provided with a plurality of nozzle outlets, which can be designed as fluid-permeable pores within the nozzle. This can, for example, prevent local and temporal oxygen peaks.

[0064] According to a second aspect, the presented invention relates to a biogas plant for producing biogas.

[0065] The presented biogas plant comprises a container, at least one sensor arranged in the container, a feed system configured to introduce an oxygen-containing gas stream into the container, and a computing unit configured to perform a possible embodiment of the presented process.

[0066] In the context of the presented invention, a computing unit is understood to be a computer, a processor, a control unit, or any other programmable circuit. The container provided according to the invention is, in particular, an industrial fermenter with a volume greater than three cubic meters. Alternatively, the reaction vessel or fermenter can also be smaller.

[0067] It may be provided that the at least one sensor comprises an oxygen detection sensor for oxygen, an optical sensor, in particular a spectrometer, an electrochemical sensor, in particular a Clark electrode, a methane concentration sensor, a hydrogen concentration sensor, a carbon dioxide concentration sensor, a hydrogen sulfide concentration sensor, an ammonium concentration sensor, an ammonia concentration sensor and / or a flow rate sensor.

[0068] An oxygen sensor can detect oxygen before and / or after the introduction of the oxygen-containing gas stream. Preferably, the oxygen concentration before introduction is > 20 vol%, preferably > 90 vol%.

[0069] Preferably, the biogas plant may further comprise a biogas quantity sensor, a biogas residual potential sensor, a biological activity sensor, a microorganism detection sensor, a temperature sensor, a dry matter sensor, in particular an organic dry matter sensor, a free organic acid sensor, a total inorganic carbon sensor, a pH sensor, an electrical conductivity sensor, a redox potential sensor, an acid detection sensor and / or a viscosity sensor.

[0070] It may further be provided that the supply system comprises a multitude of supply channels which fluidly couple at least one gas storage tank with a container containing the microorganisms, with an injection valve arranged on each supply channel which can be selectively opened or closed by the computing unit.

[0071] A supply system with multiple channels, each selectively opened or closed by its own injection valve, allows for local distribution of the oxygen-containing gas stream within the container. Specifically, different gas flows can be directed through different channels, introducing varying amounts of oxygen into the container.

[0072] It may further be provided that the supply system includes a mixing unit configured to introduce the oxygen-containing gas stream into the multitude of supply channels, the mixing unit being configured to change an oxygen concentration in the oxygen-containing gas stream.

[0073] In particular, the mixing system can be configured to increase or decrease the oxygen concentration in the oxygenated gas stream, or to set it to a predetermined value. For this purpose, the mixing system can include a metering valve and / or an oxygen concentration sensor. A first exemplary control loop can include monitoring the composition and / or quantity of the product gas and introducing an oxygenated gas stream, with the introduction depending on the product gas composition and / or quantity. The introduction of the oxygenated gas stream can be controlled such that the oxygen content in the product gas does not exceed 1% by volume. Higher oxygen contents indicate a reduced survival rate of the obligate anaerobes and, consequently, a reduced biogas yield, particularly a reduced methane yield.

[0074] A second exemplary control loop can include monitoring the oxygen partial pressure in the vessel and introducing an oxygen-containing gas stream. Monitoring along the effective path of the introduced oxygen is particularly advantageous, i.e., along the oxygen's ascent path within the vessel contents or the fermentation substrate. With increasing circulation of the fermentation substrate, for example, by means of an agitator, the effective path can be extended, allowing for multiple measurement points. If the partial pressure at one or more measurement points deviates from an optimum, the gas stream introduction can be regulated to maximize the survival of the obligate anaerobes and thus the gas yield.

[0075] A third exemplary control loop can comprise a combination of the first and second control loops described above. Further features, details, and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. The drawings show:

[0076] Fig. 1 shows a possible embodiment of the presented method,

[0077] Fig. 2 shows a possible design of the presented biogas plant.

[0078] Figure 1 shows a process 100 for producing biogas.

[0079] The process 100 comprises a cultivation step 101 in which microorganisms are cultivated in a container, the microorganisms comprising facultative anaerobes and obligate anaerobes.

[0080] Furthermore, the process 100 comprises a control step 103 in which an oxygen-containing gas stream is introduced into the container. The amount of oxygen introduced into the container by the gas stream is adjusted based on measurements obtained by at least one sensor arranged on the container, such that the facultative anaerobes operate in an aerobic metabolic state and the obligate anaerobes survive. The adjustment is made in such a way that the metabolism of the obligate anaerobes is not significantly reduced, thus increasing the biogas yield or maintaining a comparatively high level. The cultivation step 101 and the control step 103 can occur concurrently.

[0081] In particular, the quantity of oxygen-containing gas and / or the oxygen concentration in the oxygen-containing gas can be regulated. For this purpose, oxygen or oxygen-containing gas can be supplied from a gas storage tank, for example. Alternatively, ambient air can be used as the oxygen-containing gas, whereby, regardless of the other configuration of the embodiment, it can be provided that the ambient air is treated by enriching it with a desired quantity of oxygen before it is introduced.

[0082] For example, the amount of oxygen introduced into the container via the gas flow can be regulated based on changes in values ​​determined by at least one sensor. This can be achieved by measuring the change over time and adjusting the amount of oxygen introduced into the container relative to the measured change, i.e., increasing or decreasing it.

[0083] Alternatively, the amount of oxygen introduced into the container by the gas flow can be iteratively changed with a predetermined step size or dosage in order to minimize any change in values ​​in the biogas plant caused by the amount of oxygen introduced into the container by the gas flow.

[0084] Figure 2 shows a biogas plant 200 for producing biogas. The biogas plant 200 comprises a container 201, sensors 203 arranged in the container 201, a feed system 205 configured to introduce an oxygenated gas stream into the container 201, and a computing unit 207 configured to perform the process 100 according to Figure 1.

[0085] The computing unit 207 is communicatively coupled with the sensors 203 and the feed system 205, for example via a wireless interface such as WLAN. Accordingly, the biogas plant 200 can be monitored and controlled remotely, for example from a central monitoring room, by setting limit values ​​and / or control parameters, in particular the step size with which the amount of oxygen introduced into the container 201 is changed.

[0086] Furthermore, a control loop 207 can be monitored or executed on the computing unit, in which the feed unit serves as a controller.

[0087] In one embodiment, oxygen injection lances serve to introduce the oxygen-containing gas stream as deeply and spatially distributed as possible into the container contents, thus maximizing the effective range. The oxygen injection lances are supplied with oxygen from the ambient air, with an oxygen content of at least 90 vol.%, by a pressure swing absorption system and an associated compressor unit. The invention is not limited to one of the embodiments described above, but can be modified in numerous ways. All claims, descriptions, and the

[0088] The features and advantages shown in the drawing, including design details, spatial arrangements and process steps, can be essential to the invention both individually and in various combinations.

[0089] Reference symbol:

[0090] 100 procedures

[0091] 101 Cultivation Step

[0092] 103 Control step 00 Biogas plant 01 Tank 03 Sensor 05 Feed system 07 Computing unit

Claims

Claims:

1. Method (100) for producing biogas, wherein the method (100) comprises: Cultivating (101) microorganisms in a container (201), wherein the microorganisms comprise facultative anaerobes and obligate anaerobes, Introducing (103) an oxygen-containing gas stream into the container, wherein the gas stream of the oxygen introduced into the container (201) is spatially, temporally and / or quantitatively controlled as a function of at least one measured value, which is determined by means of at least one sensor (203) arranged on the container (201), such that the facultative anaerobes work in an aerobic metabolism and the obligate anaerobes survive, in such a way that the biogas yield is maximized.

2. Method (100) according to claim 1, characterized in that at least one parameter from the following list of parameters is continuously detected by means of the at least one sensor (203): oxygen concentration in a biogas produced by the microorganisms, oxygen concentration in a container contents comprising the microorganisms, oxygen partial pressure in the biogas, oxygen partial pressure in the container contents, electrochemical properties, spectral properties.

3. Method (100) according to claim 1 or 2, characterized in that, that by means of at least one sensor (203) at least one of the following parameters is detected in biogas produced by microorganisms and / or in a container containing microorganisms: methane concentration and / or methane partial pressure, hydrogen concentration and / or water partial pressure, carbon dioxide concentration and / or carbon dioxide partial pressure, hydrogen sulfide concentration and / or hydrogen sulfide partial pressure, ammonium concentration and / or ammonium partial pressure, ammonia concentration and / or ammonia partial pressure, biogas quantity, biogas residual potential, biological activity, population of at least one type of microorganism, process parameters, dry matter, organic dry matter, free organic acids, total inorganic carbon, ratio of free acids to buffer capacity, pH value, electrical conductivity, redox potential, acid profile, flow properties, viscosity, container temperature.

4. Method (100) according to claim 3, characterized in that the at least one quantity is detected by means of the at least one sensor (203) in a predetermined time range after an introduction of a quantity of the oxygen-containing gas stream into the container (201 ).

5. Procedure (100) according to one of the preceding Claims, characterized by, that the amount of oxygen is regulated by setting a mass flow rate of the oxygen-containing gas stream, setting an oxygen concentration of the oxygen-containing gas stream, selectively controlling injection valves of a large number of injection valves to introduce the oxygen-containing gas stream into the container and / or setting an activity of a stirrer to mix a container contents comprising the microorganisms.

6. Method (100) according to one of the preceding claims, characterized in that the introduction (103) of the oxygen-containing gas stream is reduced and / or stopped when at least one value determined by the at least one sensor is greater than or equal to a predetermined limit value.

7. Method (100) according to one of the preceding claims, characterized in that several sensors determine measured values ​​along the oxygen-containing gas stream.

8. Method (100) according to one of the preceding claims, characterized in that, in the event that a deviation between a determined measured value and a target value is greater than a predetermined alarm value and / or lasts longer than a predetermined alarm duration, a warning message is displayed. an output unit that reports the deviation.

9. Procedure (100) according to one of the preceding Claims characterized in that a number of values ​​are assigned to a state from a plurality of states by means of a machine learner, and that the oxygen-containing gas flow is controlled when an assigned state deviates from a predetermined target state.

10. Procedure (100) according to one of the preceding Claims characterized in that the introduction (103) is continuous.

11. Biogas plant (200) for producing biogas, wherein the biogas plant (200) comprises: a container (201), at least one arranged in the container (201) sensor (203), a feed system (205) configured to introduce an oxygenated gas stream into the container (201), a computing unit (207) wherein the computing unit (207) is configured to a To carry out a method (100) according to any one of claims 1 to 10.

12. Biogas plant (200) according to claim 11, characterized in that the at least one sensor (203) is an oxygen detection sensor for oxygen, a spectrometer, an electrochemical sensor, in particular a Clark electrode, a methane concentration sensor, a hydrogen concentration sensor, a carbon dioxide concentration sensor, a hydrogen sulfide concentration sensor, an ammonium concentration sensor, an ammonia concentration sensor, a flow rate sensor, a biogas quantity sensor, a biogas residual potential sensor, a biological activity sensor, a microorganism detection sensor, a temperature sensor, a dry matter sensor, in particular an organic dry matter sensor, a free organic acid sensor, a total inorganic carbon sensor, a pH sensor, an electrical conductivity sensor, a redox potential sensor, an acid detection sensor and / or a viscosity sensor.

13. Biogas plant (200) according to claim 11 or 12, characterized in that the feed system (205) comprises a plurality of supply channels which fluidly couple at least one gas storage tank with a container contents comprising the microorganisms, wherein an injection valve is arranged on each supply channel which can be selectively opened or closed by the computing unit (207).

14. Biogas plant (200) according to claim 13, characterized in that the feed system (205) comprises a mixing plant configured to introduce the oxygen-containing gas stream into the plurality of supply channels, wherein the mixing plant is configured to change an oxygen concentration in the oxygen-containing gas stream.

Images