METHOD FOR OPERATING A BREWERY AND BREWERY WITH BIOGAS PRODUCTION

Description

[0001] The invention relates to a method for operating a brewery with biogas production and a brewery with a brewing plant, a biomass conversion plant and a combined heat and power plant.

[0002] Beer brewing plants are known to require comparatively large amounts of thermal and electrical energy for heating, boiling, and cooling processes, as well as for the operation of the associated equipment. Furthermore, many quality-determining parameters depend on the amount of energy used in the individual processes, so these can only be reduced to a limited extent through process optimization alone. Therefore, efforts are being made to reduce fossil energy demand and cover it with renewable sources without compromising product quality.

[0003] The most important residues generated during brewing processes are spent grain, (old) yeast, malt dust, and wastewater. All are characterized by a relatively high content of biochemical substances, which in principle allow for energy recovery. Biogas plants are known for this purpose, producing methane-containing biogas from these residues. This biogas is cleaned, usually mixed with natural gas, and burned in a boiler or combined heat and power plant. The addition of methane is necessary because conventional biogas plants either cannot generate the amount of energy needed to meet demand or would have to be so large to fully utilize the residues that they would not be economically viable. This is mainly due to the spent grain, which makes up the largest proportion of the residues and is converted relatively inefficiently by microorganisms due, among other things, to its high lignin content.Since the fermentation time for sufficient conversion would be several days, the resulting spent grain is often not used for biogas production, or only in comparatively small amounts, for economic reasons, and is usually disposed of in a non-renewable manner. Thus, essentially recyclable energy is lost to a considerable extent.

[0004] DE 10 2016 014 103 B4 discloses a modular biomass conversion process in which biological residues such as wastewater or sewage sludge are first pretreated by dispersion and proteolysis to separate a protein hydrolysate and then by acidification and separation of a mineral fertilizer in order to finally obtain biogas and treated wastewater with an increased recovery rate compared to single-stage processes.

[0005] Although conventional biogas plants in breweries can achieve a relatively high methane content of 70 to 80% compared to the usual 60 to 65%, this is only possible with the exclusive use of wastewater, as this usually has a high pH value and a high carbohydrate content, which are advantageous for conversion.

[0006] Furthermore, DE 10 2014 001 907 A1 describes a process for the material and energy recovery of biogenic residues from breweries by using the residues in a wet fermentation process. This process involves, on the one hand, making desulfurized biogas obtained during fermentation available for energy recovery, and, on the other hand, concentrating the entire nutrient potential in the form of nitrogen, phosphorus, potassium, and sulfur in a fertilizer fraction obtained from the fermentation residues. For this purpose, the residues are first suspended and then aerobically hydrolyzed. The resulting hydrolyzate is fed into the biogas-producing fermenter system. However, the resulting biogas yield is unsatisfactory. Furthermore, the predominantly energy recovery of the nutrients contained in the residues is increasingly viewed as inadmissible, as this violates, for example, the requirements of the EU Circular Economy Regulation.

[0007] DE 10 2018 009592 A1 further describes a process for optimizing the biological treatment of municipal and industrial wastewater with regard to the resulting wastewater quality and comprehensive utilization of constituents, incorporating the biomass conversion known from DE 10 2016 014 103 B4. Accordingly, the carbon content of the wastewater can be increased by adding a larger amount of biowaste, such as spent grain from a brewery, and a nutrient solution containing amino acids and peptides can be obtained from the protein content of the biomass through enzymatic hydrolysis. After processing the excess sludge with acidification, biogas with a methane content of approximately 57% is produced in a fermentation stage from the acid solution and excess process water. The biogas can be used to generate electricity and heat in a combined heat and power plant, which are used to meet the energy requirements of the wastewater treatment process.

[0008] In contrast, there is therefore a need for further improvement to ensure the most energy-efficient operation of brewing plants, with the most comprehensive utilization of all the residual materials generated, with the least possible expenditure on equipment and / or with flexible adaptation to energy requirements that fluctuate depending on the operation.

[0009] The stated object is achieved with a method according to claim 1 and a brewery according to claim 13. Advantageous embodiments are specified in the subclaims. The method is used to operate a brewery and comprises a modularly controllable biomass conversion of brewing residues comprising spent grain and alkaline carbohydrate-containing wastewater in converter stages. During biomass conversion, at least the spent grain is pretreated by proteolysis with separation of protein hydrolysate in a first converter stage and by acidification, and in particular ion exchange, with separation of mineral fertilizer in a second converter stage. Based on this, biogas is obtained by biogas fermentation in a third converter stage, with simultaneous treatment of the wastewater, for example, into process water. Furthermore, the obtained biogas is combusted at least in part to supply the brewery with electricity and / or heat.

[0010] This means that biomass contained in the spent grain and wastewater can be processed together and utilized with unexpectedly high methane yield.

[0011] Pretreatment of brewing residues, particularly the separation of mineral fertilizers prior to biogas fermentation, improves the conversion rate of the microorganisms, making biogas production significantly more economical in terms of both procurement and operation than is traditionally the case for breweries. Surprisingly, it has been found that with stepwise biomass conversion, even when the majority of spent grain is used in combination with wastewater, methane contents of up to over 90% can be achieved in biogas. The separation of mineral fertilizers as pretreatment in combination with the alkaline and relatively carbohydrate-rich wastewater therefore leads to an unexpected increase in the methane content.

[0012] The additional methane produced in this way contributes to energy-self-sufficient brewing operations and can be stored, used for other purposes, or economically utilized in the event of a gas surplus. This allows the nominal thermal and electrical energy requirements of a brewing plant to be met renewably, minimizing the need for external energy supplies. In other words, essentially energy-self-sufficient brewing operations are possible. This ensures both cost-effective and sustainable production.

[0013] In addition, the separated valuable materials, i.e. protein hydrolysate and / or an optionally obtained protein fraction, for example previously filtered out, can be economically utilized as raw materials for the production of food, as can separated mineral fertilizer for use in agriculture.

[0014] Biomass conversion takes place in a modular biomass conversion plant with serially connected and separately controllable converter stages. The incoming brewery residues are thus treated in separate, mechanically controllable and correspondingly coordinated process stages. This means that, for example, the relative amounts of valuable materials separated during pretreatment, such as protein fractions, protein hydrolysate, and / or mineral fertilizers, can be coordinated with the relative amount of biogas produced by biogas fermentation, depending on the composition of the brewery residues and / or biogas demand.

[0015] A particular advantage of step-by-step biomass conversion for breweries is that solid and liquid brewing residues can be processed and utilized in a single facility. In conventional biogas plants, spent grain typically must be treated separately from wastewater. This is avoided by the described pretreatment of spent grain, which allows any remaining solid particles in the biomass conversion plant to be converted into liquid phases and mixed with the brewing plant wastewater, i.e., wastewater from brewing processes or other processes in the brewery. This avoids the yield losses associated with conventional biogas production.

[0016] The biomass conversion of brewery residues can include cell disruption in the first and / or second converter stage. Such cell disruption can increase the effectiveness of the described process and, due to the relatively large equipment required, may be integrated optionally, depending on economic considerations. Cell disruption then primarily takes place in the first converter stage, but is also possible in principle in the second converter stage.

[0017] However, the biomass conversion of brewery residues does not necessarily require cell disruption in the first and / or second converter stage. For example, mechanical comminution (which does not necessarily result in cell disruption) of the brewery residues may be sufficient.

[0018] The protein hydrolysate can be separated by separation, which can be, for example, a separation, in particular a plate separation, or, for example, membrane filtration, in particular ultrafiltration. Additionally or alternatively, a nutrient and fertilizer solution containing the mineral fertilizer can be separated by anaerobic acidification and subsequent separation, which can be, for example, a separation, in particular a plate separation, or, for example, membrane filtration, in particular ultrafiltration, and by downstream ion exchange. Such separation is particularly efficient and facilitates the further processing of the resulting fractions.

[0019] For this purpose, the biomass conversion plant may further comprise: a separation unit assigned to the first converter stage for separating the protein hydrolysate by means of separation, in particular centrifugal separation, or for membrane filtration, in particular ultrafiltration; and / or a separation unit assigned to the second converter stage for separation, in particular centrifugal separation, or for membrane filtration, in particular ultrafiltration, with a downstream ion exchanger for separating a nutrient and fertilizer solution containing the mineral fertilizer.

[0020] To increase the purity of the separated protein hydrolysate (comprising amino acids and peptides), an additional purification step is possible, for example, by protein precipitation followed by separation of the precipitated peptides and / or amino acids by filtration and / or centrifugal separation. Additionally or alternatively, purification of the protein hydrolysate by chromatography is possible.

[0021] Accordingly, the biomass conversion plant may comprise at least one purification unit associated with the first converter stage for additional purification of the (separated) protein hydrolysate, for example: a unit for protein precipitation and subsequent filtration and / or centrifugal separation of precipitated peptides and / or amino acids; and / or a unit for chromatographic separation (chromatography unit).

[0022] The above additional purification of the protein hydrolysate is possible with all described and / or illustrated embodiments of the process and the biomass conversion plant and is therefore to be understood as a general option for protein hydrolysate separation, even where this is not explicitly mentioned.

[0023] Preferably, retentate (generated from the brewing residues) to be conveyed from the first converter stage to the second converter stage is temporarily stored in at least one buffer vessel, particularly during discontinuous operation of the first converter stage and continuous operation of the second converter stage. Optionally, intermediate storage of medium / acid water (generated from the retentate) is also possible between the second and third converter stages, with the latter then preferably also being operated continuously. Thus, the first converter stage can operate discontinuously depending on the accumulation / availability of the brewing residues, i.e., in so-called batch operation, while in the second and third converter stages, essentially continuous operation is possible, which is more favorable for microorganisms and the biochemical processes based on them.

[0024] Preferably, a first portion of the biogas produced is temporarily stored in the brewery area, and / or a second portion of the biogas is fed into an external gas network. The first and / or second portion of the biogas can be fed into the intermediate storage or external use by mechanical control, for example, by means of at least one electronically controlled gas distributor.

[0025] Through step-by-step biomass conversion, methane can, in principle, be produced in excess due to the overall energy balance of brewing processes. Excess biogas / methane can be stored on-site and used, for example, to restart brewing processes or associated plant components after a maintenance break. If excess biogas is not used for an extended period, it may be advantageous to feed it into an external gas grid and thus utilize it economically due to the volatility of methane. Excess biogas could also be used to supply other production facilities, such as lemonade production, for example, if there are no or only a few usable residues.

[0026] Preferably, a third portion of the biogas obtained is burned in a combined heat and power plant and / or a fourth portion of the biogas is burned in a boiler to generate heat (in the form of steam or hot water), for example for hot water production (for example, for mashing water, sparging water, and / or rinsing water) or for hot water production as heating water (for example, for heating heat consumers such as a mashing device). This allows the energy contained in the biogas to be flexibly and efficiently converted into heat and electricity, depending on the heat and power requirements of the brewing plant. The third and / or fourth portion of the biogas can be fed to the combined heat and power plant or the boiler by mechanical control, for example by means of at least one electronically controlled gas distributor.

[0027] Preferably, the electricity generated with the third portion of the biogas is fed to an internal electricity consumer, in particular the brewing plant, and / or to an internal charge storage facility, and / or the electricity is fed proportionally into an external power grid.

[0028] Due to the increased efficiency of biogas production, the combined heat and power plant can produce more electricity from the brewery's waste than the brewery itself requires. Such excess capacity could be buffered by storage on the brewery premises and / or used specifically for load regulation in coordination with a power grid operator. For example, the coordinated operation of charging stations for electric vehicles is also conceivable.

[0029] Preferably, the thermal energy generated from the third and / or fourth portion of the biogas is temporarily stored in a heat storage unit within the plant and fed into the brewing process. This allows the available thermal energy to be buffered for a limited time and, if necessary, combined with other heat sources in the brewing plant, particularly renewable ones.

[0030] The brewing residues fed into the biomass conversion process preferably consist of at least 20 and especially 50 wt.% spent grain. The otherwise relatively poorly utilized biomass contained in the spent grain, such as the lignin it contains, can be converted into biogas with a relatively high methane content in an unexpectedly efficient manner through multi-stage biomass conversion together with wastewater.

[0031] Preferably, the biogas is produced with a methane content of at least 70%, especially at least 90%. This eliminates the need for natural gas and promotes energy-self-sufficient brewing plant operation.

[0032] Preferably, yeast and / or malt dust and / or hot and / or cool trub are also added to the biomass conversion process. This allows all major residues from brewing processes to be pretreated together and efficiently converted into biogas.

[0033] Preferably, biomass is mechanically recirculated from the second to the first converter stage and / or from the third to the second converter stage. This allows the pretreatment of the biomass for its fermentation, including the separation of valuable materials, to be adapted to the composition of the supplied brewery residues and / or the required biogas quantity and / or a specified methane content of the biogas.

[0034] Preferably, the carbon dioxide content in biogas is reduced by methanation with the addition of hydrogen and the use of methane bacteria from biogas fermentation. This enables essentially CO2-neutral brewing processes. Furthermore, the methane content of the resulting biogas can be further increased.

[0035] Preferably, the separated protein hydrolysate contains raw materials for processing in the food industry, in particular peptides and amino acids, and / or the separated mineral fertilizer contains at least one agricultural fertilizer, in particular ammonium sulfate, diammonium hydrogen phosphate, potassium phosphate, calcium sulfate and / or magnesium sulfate.

[0036] Through the described separation of valuable materials in the pre-treatment stages, nutrient-containing components of the brewing residues, such as proteins and carbohydrates, can also be recycled for the production of food, for example, in contrast to energetic utilization by means of biogas fermentation.

[0037] The brewery comprises a brewing plant, a biomass conversion plant and a combined heat and power plant, whereby the biomass conversion plant for the biomass conversion of residues from the brewing plant, in particular spent grains, comprises: a first converter stage for proteolysis with separation of protein hydrolysate; a second converter stage for acidification, and in particular for ion exchange, with separation of mineral fertilizers; and a third converter stage for the production of biogas for the combined heat and power plant through biogas fermentation, in particular with simultaneous treatment of wastewater to process water.

[0038] For this purpose, the converter stages are preferably controlled separately and / or mechanically for mutual coordination.

[0039] The first and second converter stages serve to pretreat the incoming brewery residues for more effective biogas fermentation in the third converter stage and also to separate valuable materials. The separated and discharged mineral fertilizers would otherwise reduce the yield of the biogas fermentation.

[0040] The first and / or second converter stage can also be designed for cell disruption.

[0041] In contrast, the first and / or second converter stage can also be designed only for the mechanical comminution of the brewing residues, although this does not necessarily result in cell disruption.

[0042] At least one buffer vessel (buffer tank) can be connected between the first and second converter stages and / or between the second and third converter stages, in order to temporarily store retentate from the first converter stage for the second converter stage, or to temporarily store medium (sour water) from the second converter stage for the third converter stage. The retentate / medium (sour water) can thus be kept available for continuous further processing in the second / third converter stage, particularly when the first converter stage is shut down.

[0043] Thus, depending on the beer production, the first converter stage can be operated discontinuously (batchwise or as a batch process) and can be idle or in operation, while the biochemical processes (based on microorganisms) in the second and third converter stages can be maintained continuously.

[0044] Preferably, the brewery further comprises at least one gas storage facility for temporarily storing the biogas obtained and / or a heat storage facility for temporarily storing the heat obtained from the biogas and / or a charge storage facility for temporarily storing the electricity generated from the biogas in the combined heat and power plant. This allows the biogas to be used efficiently and as needed for various brewing processes, such as for heating and cooking brewing products in the form of heat, and for cooling and transporting brewing products in the form of electricity.

[0045] Preferably, the brewery further comprises a mechanically controllable gas distributor for the gradual distribution of the biogas obtained to a first portion to be temporarily stored in a gas storage facility within the plant and / or a second portion to be fed into an external gas network and / or a third portion to be combusted in the combined heat and power plant and / or a fourth portion to be combusted in a boiler within the plant.

[0046] Preferably, the brewery comprises an electronic control device for controlling the gas distributor depending on the heat and / or power requirements of the brewing system determined during operation.

[0047] This means that the biogas produced can be optimally utilized, for example, depending on different operating conditions of the brewing plant, even if there is a gas surplus in this regard, and preferably automatically, i.e. without operator intervention.

[0048] Preferably, the first and second converter stages are designed such that the separation of protein hydrolysate, and in particular also an upstream separation of a protein-containing fraction resulting from the cell disruption, as well as the separation of mineral fertilizers can each be controlled separately by machine.

[0049] For example, it can be advantageous to vary the operating points of residual material utilization within certain limits. For example, the proportion of protein hydrolysate obtained can be reduced, thereby increasing the yield of biogas. However, when production is shut down, i.e., when energy demand is relatively low, predominantly or exclusively protein hydrolysate could be obtained, and biogas production could be throttled or stopped accordingly.

[0050] A preferred embodiment of the invention is illustrated in the drawings. Fig. 1: a diagram of the process with multi-stage biomass conversion; Fig. 2: a diagram of a brewery with media flows; Fig. 3: processes and material flows of biomass conversion; Fig. 4: an embodiment of the process according to Fig. 1 with additional media buffering between the converter stages; and Fig. 5 a design of the processes and material flows according to Fig. 3 with additional purification of the protein hydrolysate.

[0051] As the Fig. 1 As can be seen, the process described here can be carried out in a brewery 1 with a brewing plant 2, a biomass conversion plant 3 and a combined heat and power plant 4.

[0052] The biomass conversion plant 3 comprises, for the biomass conversion of brewing residues 5 with spent grain 5a and wastewater 5b and optionally also with yeast 5c and / or malt dust 5d (and / or hot trub and / or cool trub), a first converter stage 3a for optional cell disruption and proteolysis with separation of protein hydrolysate 6a; a subsequent second converter stage 3b for acidification, and optionally further for ion exchange, with separation of mineral fertilizer 6b; and a subsequent third converter stage 3c for the production of biogas 7 for the combined heat and power plant 4 through biogas fermentation, preferably with simultaneous treatment of the wastewater 5b to process water 8.

[0053] The first and second converter stages 3a, 3b serve, on the one hand, to pretreat at least the spent grain 5a and, if applicable, other added brewing residues 5 for their biogas fermentation in the third converter stage 3c, and, on the other hand, to separate valuable materials 6 from the brewing residues 5, i.e., the protein hydrolysate 6a (comprising peptides and amino acids) and the mineral fertilizer 6b (e.g., ammonium fertilizer). In principle, a protein fraction 6c obtained after initial cell disruption could also be recovered as valuable material 6 in the first converter stage 3a. However, this should only be understood as an additional utilization option, for example, depending on the composition of the brewing residues 5.

[0054] The mineral fertilizers 6b as a whole generally inhibit biogas fermentation. Thus, the upstream separation and discharge of mineral fertilizer 6b increases the methane yield of the biogas fermentation described here and thus its efficiency.

[0055] The biomass conversion plant 3 comprises an electronic control device (not shown) for the mechanical control of the individual converter stages 3a, 3b, 3c, on the one hand independently of one another and on the other hand in combination with one another or in coordination with one another.

[0056] Thus, the chemical and physical processes taking place in the converter stages 3a, 3b, 3c, for example with regard to the separation of the valuable materials 6 and / or the recycling of biomass 9 and / or the production of biogas 7, can be specifically optimized.

[0057] For example, the pretreatments taking place in the biomass conversion plant 3 for the subsequent biogas fermentation and the respective separation of valuable materials 6 can be adapted to the composition of the supplied brewing residues 5 and / or the required amount of biogas 7 and / or to a predetermined methane content of the biogas 7.

[0058] In the Fig. 1 As an example, a machine-controlled return of biomass 9 from the second converter stage 3b to the first converter stage 3a and / or from the third converter stage 3c to the second converter stage 3b is schematically indicated.

[0059] For possible process variants of the multi-stage biomass conversion in the converter stages 3a, 3b, 3c, reference can in principle be made to the embodiments described in DE 10 2016 014 103 B4.

[0060] In contrast to the processes described there, the pretreatment in the first two converter stages 3a, 3b in the process described here is carried out on brewing residues 5 with spent grain 5a, which preferably makes up the largest proportion by weight of the total converted brewing residues 5 or at least 20% thereof.

[0061] For this purpose, wastewater 5b from the brewing plant 2 is also fed to the biomass conversion plant 3, for example, the third converter stage 3c, as brewing residue 5. The biomass contained in the spent grain 5a and the wastewater 5b is thus regeneratively utilized in the same biomass conversion plant 3, which also results in a particularly high methane yield.

[0062] As the Fig. 2As can be seen, in an expanded embodiment, the brewery 1 can comprise: at least one gas storage unit 10 for the temporary storage of biogas 7 obtained; and / or a heat storage unit 11 for the temporary storage of heat 12 obtained from the biogas 7, for example a stratified storage unit for hot water as a heating medium; and / or an electrical charge storage unit 13 (accumulator) which is charged with electrical current 14 obtained from the biogas 7 in the combined heat and power plant 4 and supplies electrical current 14 to the brewing plant 2 when electricity is required.

[0063] Thus, the biogas 7 can be used efficiently and as needed for different brewing processes in the brewing plant 2, for example for heating and cooking in the form of heat 12 and for cooling and transport in the form of electricity 14.

[0064] Excess electrical power 14 from the combined heat and power plant 4 could, if necessary via the charge storage 13, be fed into an external power grid (not shown) and thus utilized.

[0065] The brewery 1 preferably further comprises a mechanically controllable gas distributor 15 for the gradual distribution of the obtained biogas 7 to a first portion 7a of the biogas 7 to be temporarily stored within the plant in the gas storage 10 and / or a second portion 7b of the biogas 7 to be fed into an external gas network (not shown) and / or a third portion 7c of the biogas to be combusted in the combined heat and power plant 4 and / or a fourth portion 7d of the biogas 7 to be combusted within the plant in a boiler 16 to generate heat 12.

[0066] The gas distributor 15 can comprise valves in a manner known in principle and / or can be controlled / regulated by an electronic control device 17 (only schematically indicated) of the brewery 1, for example as a function of a heat and / or power requirement of the brewing system 2 determined as a function of the operation.

[0067] With the gas distributor 15, biogas 7 can be suitably distributed and thus optimally utilized depending on different operating states of the brewing plant 2, preferably automatically, i.e., without operator intervention. In the event of a gas surplus, i.e., when biogas 7 is produced in excess of the existing energy demand of the brewing plant 2, its first and / or second portions 7a, 7b can, for example, be increased in order to temporarily store excess biogas 7 or utilize it externally.

[0068] For the gas distributor 15, nominal distribution ratios for specific operating states of the brewing system 2 can be specified within the framework of the process control, for example, by appropriate programming of the control device 17. For example, the first portion 7a could be nominally 20%, the second portion 7b nominally 0%, the third portion 7c nominally 70%, and the fourth portion 7d nominally 10%.

[0069] Nominal distribution ratios for the generated biogas 7 could then be automatically adjusted within suitably specified limits, for example, depending on the operating status of the brewery 2 and the requirements for practical operation of the combined heat and power plant 4 or the boiler 16 and / or the remaining capacity of the gas storage facility 10. The use of the generated biogas 7 can be optimized particularly flexibly in this way.

[0070] Depending on the capacity of the biomass conversion plant 3, it is conceivable to integrate additional renewable energy sources, for example, for charging the charge storage device 13. Here, for example, a photovoltaic solar module unit 18 for electricity generation is used. Although not shown, a solar thermal system can be used alternatively or in addition to a boiler 16 for the regenerative generation of process heat.

[0071] In the Fig. 1 In addition, the generally known raw materials and products of beer brewing in the brewing plant 2 as well as auxiliary materials for the biomass conversion plant 3 are schematically indicated, namely malt 21 (or other starchy raw materials such as barley, corn, rice), fresh water 22, hops 23, beer 24, carbon dioxide 25, acid 26, alkali 27 and enzymes 28.

[0072] With the described process, CO2-neutral production operation of Brewery Plant 2 is also possible, in addition to or as an alternative to energy-self-sufficient production operation.

[0073] Additionally, the carbon dioxide content in biogas 7 can be reduced by methanation with the addition of hydrogen and the use of methane bacteria from biogas fermentation, thereby increasing the methane content. Other processes are also available for CO2 reduction at the end of biogas fermentation, see, for example, the processes described in DE 10 2016 014 103 B4.

[0074] In addition to the obligatory brewing plant 2, the biomass conversion plant 3 and the combined heat and power plant 4, the brewery 1 can be designed modularly with individual of the described plant components or expanded if necessary, for example with a gas storage facility 10, an electrical charge storage facility 13 and / or a gas distributor 15. Depending on the regenerative capacity of the biomass conversion plant 3 and the flexibility of biogas use and / or intermediate storage of the individual energy sources made possible by the plant components, the external energy and resource requirements of the brewing plant 2 can be reduced to the point of energy self-sufficient operation through a suitable modular design / expansion of the brewery 1.

[0075] A corresponding system design is possible, for example, based on simulations and consumption measurements. Practical experience has also confirmed that the biomass contained in the brewing residues 5 and the energy recovered from them are sufficient to supply the brewing system 2, as part of the described brewery 1, with energy self-sufficiency.

[0076] The fundamentally desired energy-self-sufficient operation of brewery plant 2 is, based on the multi-stage biomass conversion in biomass conversion plant 3 and the resulting increased recovery efficiency, also possible with only some of the components of brewery 1 described above. For example, feeding into external grids, in-plant gas storage, solar power generation, or the like may be unnecessary.

[0077] Even if retrofitting existing brewing plants 2 with certain components of the brewery 1 described here should not be possible in individual cases, for example for structural or economic reasons, the basic configuration of the brewery 1 described already allows for a significantly reduced need for external energy supply compared to conventional breweries with biogas production, up to and including energy-self-sufficient operation of brewing plants with comparatively low equipment expenditure.

[0078] When we talk about malt dust, this includes dust from any starch carrier such as barley, rice or corn.

[0079] When we talk about brewing processes, we also include preparatory or post-processing processes such as cleaning processes.

[0080] The Figure 3shows an embodiment of the process with processes and material flows of biomass conversion in the first, second and third converter stages 3a, 3b and 3c.

[0081] Accordingly, in the first converter stage 3a, the brewing residues 5 supplied in the form of spent grain 5a, yeast 5c, and / or malt dust 5d (and / or hot trub and / or cool trub) are first suspended 31 with fresh water 22 to form a suspension having, for example, a dry matter content of 10 to 12%. To reduce the water requirement, process water 8 can be used for the suspension instead of fresh water 22 or in addition thereto, and / or slurry water generated during the brewing process and / or batch water collected during plant cleaning using a CIP (cleaning in place) system.

[0082] The brewing residues 5 thus suspended are further subjected to dispersion 33 (distribution of a dispersed phase in a fluid phase) and comminution 34 in the first converter stage 3a. For comminution 34, a colloid mill or a stirred ball mill, for example, can be used.

[0083] The comminution 34 can optionally be carried out up to a cell disruption 35, but this is in principle also possible by adding enzymes and / or in particular simultaneous ultrasound treatment or by other chemical-physical means.

[0084] The comminuted suspension is then subjected to proteolysis 36a in the first converter stage 3a. Proteolysis 36a is always understood here as an enzymatic hydrolysis 36 of proteins. The (optional) cell disruption 35 and the (mandatory) proteolysis 36a can be performed in a common container or sequentially in separate containers.

[0085] Proteolysis 36a takes place in a heatable container, with the supplied suspension being kept as homogeneous as possible, for example, by means of a stirrer or a pumping device. For an efficient energy input to achieve a required enzyme activity 28 (see Fig. 1 ) suitable reaction temperature, a so-called pillow-plate heating surface (with pillow-like unevenness on the product side) or the like can be used.

[0086] The primary goal of enzymatic hydrolysis 36, i.e., proteolysis 36a, is the degradation of proteins into peptides and amino acids, so that after proteolysis 36a, these are present in (chemically) dissolved form and can be separated, discharged, and thus separately utilized by subsequent first separation 37. For proteolysis 36a, technical enzymes 28 can be added in pure form or as a functional mixture.

[0087] Additional technical enzymes 28 can also be added, as hydrolysis 36 does not have to be limited to proteolysis 36a. For example, lignocellulosic ingredients can be cleaved during proteolysis 36a by adding additional technical enzymes 28. Such a procedure is advantageous but not absolutely necessary.

[0088] The first separation 37 of peptides and amino acids in the form of liquid protein hydrolysate 6a is possible, for example, by means of a first separation unit 38 for separation, in particular centrifugal separation, or for membrane filtration, in particular ultrafiltration. However, other separation devices, for example other separators, decanters and / or centrifuges, can also be used alternatively or additionally upstream. The resulting retentate can optionally first be fed to a buffer vessel 20 (in the Figure 4shown). Alternatively, it can be suitably concentrated, for example with a dry matter content of 15 to 25%, and fed directly into the second converter stage 3b. All ingredients that are not dissolved in the hydrolysis 36 or are not discharged as a result of the first separation 37 are therefore concentrated in the retentate. The first separation 37 is assigned to the first converter stage 3a in terms of process technology. The first separation unit 38 used for this purpose can, however, be arranged relatively flexibly in the area of ​​the first converter stage 3a or between it and the second converter stage 3b.

[0089] Through the first separation 37 of the protein hydrolysate 6a, preferably only 50 to 80% of the original nitrogen content (of the brewing residues 5 fed to the first converter stage 3a) is fed to the second converter stage 3b for anaerobic hydrolysis / acidification 39 there. This takes place in a fermentation process with acid-forming microorganisms prior to biogas production, producing acid gas 40 consisting essentially of CO2, H2, and H2S. This acid gas 40 can be used for energy recovery after suitable purification, for example in the combined heat and power plant 4.

[0090] The anaerobic hydrolysis / acidification 39 is carried out in a temperature-controlled (by heating and / or cooling) stirred tank (not shown) of the second converter stage 3b. For the purpose of a second separation 41, the entire fermentation fluid is continuously circulated through a suitable separation device, in particular a second separation unit 42 for membrane filtration, in particular ultrafiltration. However, other separation devices, such as a separator, can also be used alternatively or additionally upstream. The fermentation fluid can also be fed to a second separation 41 in a batch process.

[0091] The components that have passed into aqueous solution through acidification 39, such as ammonium, phosphate, and metal ions, are continuously separated from non-hydrolyzed solid load 9a by the second separation 41 and fed to an ion exchange 43 in an ion exchanger 44. The resulting regenerate is a nutrient and fertilizer solution 45, which contains the mineral fertilizer 6b or can be processed into it. This means that the mineral fertilizer 6b is present in the nutrient and fertilizer solution 45 in a chemically dissolved form, i.e., in liquid form, not as a suspension. For example, the ion exchanger 44 is regenerated with alkali and acid, and the associated regenerate is the fertilizer solution 45.

[0092] The nutrient and fertilizer solution 45 or the mineral fertilizer 6b is thus obtained from the liquid phase of the anaerobic acidification 39 (a pre-fermentation in the second converter stage 3b) and not from the digestate 9b of the methane / biogas fermentation 46 (the main fermentation in the third converter stage 3c).

[0093] A separation of ammonium ions in particular before the methane / biogas fermentation 46 brings enormous advantages for the efficiency of the third converter stage 3c, since ammonium ions inhibit various bacteria in the third converter stage 3c, which would severely impede the methane / biogas fermentation 46.

[0094] Due to the process sequence according to the invention with advanced nutrient separation in the form of protein hydrolysate 6a and nutrient and fertilizer solution 45 or mineral fertilizer 6b as a result of the proteolysis 36a in the first converter stage 3a and the anaerobic acidification 39 in the second converter stage 3b, i.e. before the methane fermentation 46, the third converter stage 3c can be designed to be approximately four to six times smaller than in known processes with nutrient separation there or downstream.

[0095] The first separation 37 in the first converter stage 3a, the second separation 41 in the second converter stage 3b, and the ion exchange 43 in the second converter stage 3b, each prior to the methane / biogas fermentation 46 for producing biogas 7, improve the performance of the methane-producing bacteria, which not only enables smaller plants but also leads to higher methane concentrations. The latter can be further increased by adding the generated acid gas 40 to the methane / biogas fermentation 46 (not shown), because the hydrogen contained in the acid gas 40 is converted with carbon dioxide in the biogas 7 to form methane.

[0096] The solid load 9a resulting from the acidification 39 and second separation 41 can be used as biomass 9 ( Fig. 1 ) are fed back into the first converter stage 3a.

[0097] The sour water resulting from the subsequent ion exchange 43 is fed into the third converter stage 3c to generate biogas 7 with methane bacteria. For this purpose, wastewater 5b, a component of the brewing residues 5, is also fed to the third converter stage 3c.

[0098] The fermentation residues 9b from the third converter stage 3c can be used as biomass 9 ( Fig. 1 ) should preferably be fed back to the second converter stage 3b.

[0099] By recycling biomass 9 from the third converter stage 3c to the second converter stage 3b and from the second converter stage 3b to the first converter stage 3a (preferably continuously during the ongoing process), it is achieved that no or at least less sludge resulting from the brewing residues 5 has to be disposed of in another way.

[0100] Residual wastewater 47 remaining after the methane / biogas fermentation 46 can be fed from the third converter stage 3c, for example, to a sewage treatment plant and / or used as process water 8 ( Fig. 2 ) or processed into such. For this purpose, the residual wastewater 47 is, for example, subjected to a conventional aerobic wastewater treatment process and then disinfected.

[0101] The described treatment of wastewater 5b comprises at least one anaerobic wastewater treatment, in which organic substances contained in the wastewater 5b are converted into biogas 7. This anaerobic wastewater treatment can be followed by an aerobic wastewater treatment and / or a disinfection. The aerobic wastewater treatment and / or the disinfection can also be part of the brewery 1.

[0102] The Figure 4 shows an advantageous embodiment of the method according to Figure 1with additional optional intermediate storage (buffering) of the retentate resulting from the brewing residues 5 in a buffer vessel 20 between the first and second converter stages 3a, 3b and of the medium (sour water) resulting from the retentate in a buffer vessel 20 between the second and third converter stages 3b, 3c. Above all, the buffering between the first and second converter stages 3a, 3b serves to maintain suitable process conditions for microorganisms in the second and third converter stages 3b, 3c during discontinuous operation of the upstream first converter stage 3a, to which the brewing residues 5 must generally be fed unevenly due to production reasons. The media buffering between the second and third converter stages 3b, 3c supports such an operation of the biomass conversion plant 3, but may also be dispensable.

[0103] The remaining components of the Figure 4 will refer to the explanations for Figure 1 referred to.

[0104] Since the first converter stage 3a preferably operates discontinuously (as a batch process) and the second converter stage 3b preferably operates continuously, a buffer vessel 20 is advantageous at least between the first converter stage 3a and the second converter stage 3b. Thus, the second converter stage 3b (and the third converter stage 3c) can be operated without interruption (for example, over a weekend without beer production) and only needs to be shut down for cleaning and maintenance purposes. Buffer vessels (buffer tanks or the like) 20 can be present between the first converter stage 3a and the second converter stage 3b and / or between the second converter stage 3b and the third converter stage 3c.

[0105] Since the processes in the second converter stage 3b and the third converter stage 3c are both based on microorganisms, these processes should be maintained as continuously as possible. Therefore, the second converter stage 3b should be continuously supplied with retentate from the first converter stage 3a, and the third converter stage 3c should be continuously supplied with medium (acid water) from the second converter stage 3b.

[0106] In contrast, the enzymatic processes in the first converter stage 3a are well suited for discontinuous operation (batch process). Since the brewing plant 2 generally does not produce beer around the clock and every day, and therefore cannot guarantee that the brewing residues 5 will be continuously generated or available, the interposition of a buffer vessel 20 is particularly advantageous between the first and second converter stages 3a, 3b. The preferably continuous processes in the second and third converter stages 3b, 3c could also be coordinated in such a way that media buffering between them is unnecessary. Nevertheless, this can contribute to more flexible and stable process control.

[0107] The Figure 5 shows an optional design of the biomass conversion according to Figure 3with an additional purification 37a of the protein hydrolysate 6a. Accordingly, the first separation 37 of peptides and amino acids in the form of liquid protein hydrolysate 6a in the first separation unit 38 (based on a separation, in particular centrifugal separation, or membrane filtration, in particular ultrafiltration) can optionally be improved by additional purification 37a in a downstream purification unit 48.

[0108] The purification unit 48 can, for example, be a unit for protein precipitation and subsequent filtration and / or centrifugal separation of precipitated peptides and / or amino acids and / or a unit for chromatographic separation.

[0109] With regard to the remaining components of the Figure 5 will refer to the explanations for Figure 3 referred to.

Claims

1. A method for operating a brewery (1), wherein brewing residues (5) produced therein, comprising spent grains (5a) and alkaline carbohydrate-containing waste water (5b), undergo biomass conversion by proteolysis (36a) with separation of protein hydrolysate (6a) in a first converter stage (3a), by acidification (39), and in particular ion exchange (43), with separation of mineral fertiliser (6b) in a second converter stage (3b) and by biogas fermentation (46) to obtain biogas (7) with simultaneous treatment of the waste water (5b) in a third converter stage (3c), and wherein the biogas is at least proportionally combusted to supply the brewery with electricity and / or heat.

2. The method according to claim 1, wherein the biomass conversion comprises a mechanical comminution (34) of the brewing residues (5) in the first and / or second converter stage (3a, 3b).

3. The method according to claim 1 or 2, wherein the biomass conversion comprises a cell disruption (35) in the first and / or second converter stage (3a, 3b).

4. The method according to claim 1, 2 or 3, wherein the protein hydrolysate (6a) is separated by a first separation (37) by means of separation, in particular centrifugal separation, and / or by means of membrane filtration, in particular ultrafiltration, and / or wherein a nutrient and fertiliser solution (45) containing the mineral fertiliser (6b) is separated after anaerobic acidification (39) by a second separation (41) by means of separation, in particular centrifugal separation, and / or by means of membrane filtration, in particular ultrafiltration, and by downstream ion exchange (43).

5. The method according to claim 4, wherein the first separation (37) comprises purification (37a) of the protein hydrolysate (6a) by protein precipitation, by separation of precipitated peptides and / or amino acids by filtration and / or centrifugal separation, and / or by chromatographic separation.

6. The method according to at least one of the preceding claims, wherein retentate to be conducted from the first converter stage (3a) into the second converter stage (3b) and / or acidulous water to be conducted from the second converter stage (3b) into the third converter stage (3c) is temporarily stored in at least one buffer vessel (20) in each case, in particular during discontinuous operation of the first converter stage (3a) and substantially continuous operation of the second and / or third converter stage (3b, 3c).

7. The method according to at least one of the preceding claims, wherein a first portion (7a) of the biogas (7) is temporarily stored in the area of the brewery (1) and / or a second portion (7b) of the biogas is fed into an external gas network and / or a third portion (7c) of the biogas (7) is combusted in a combined heat and power plant (4) and / or a fourth portion (7d) of the biogas is combusted in a boiler (16) within the plant.

8. The method according to claim 7, wherein the electric current (14) generated with the third portion (7c) of the biogas (7) is fed to brewing processes within the brewery (1) and / or to an internal electrical charge storage unit (13) and / or fed into an external power grid.

9. The method according to claim 7 or 8, wherein heat (12) generated from the third and / or fourth portion (7c, 7d) of the biogas (17) is temporarily stored within the plant in a heat storage (11) and fed to brewing processes.

10. The method according to at least one of the preceding claims, wherein the brewing residues (5) fed to the biomass conversion consist of at least 20 wt.%, in particular at least 50 wt.% of spent grains (5a).

11. The method according to at least one of the preceding claims, wherein yeast (5c) and / or malt dust (5d) and / or hot sludge and / or cold sludge are further supplied to the biomass conversion.

12. The method according to at least one of the preceding claims, wherein the carbon dioxide content in the biogas (7) is reduced by methanisation with the addition of hydrogen and the use of methane bacteria from the biogas fermentation, in particular in the third converter stage (3c).

13. A brewery (1) with a brewing plant (2), a biomass conversion plant (3) and a combined heat and power plant (4), wherein the biomass conversion plant for biomass conversion of residues (5) of the brewing plant comprising spent grains (5a) and alkaline carbohydrate-containing waste water (5b) comprises: a first converter stage (3a) for proteolysis (36a) with separation of protein hydrolysate (6a); a second converter stage (3b) for acidification (39), and in particular for ion exchange (43), with separation of mineral fertiliser (6b); and a third converter stage (3c) for obtaining biogas (7) for the combined heat and power plant (4) by biogas fermentation with simultaneous treatment of the waste water (5b).

14. Brewery according to claim 13, wherein the first converter stage (3a) and / or the second converter stage (3b) is further configured for mechanical comminution (34) of the brewing residues (5).

15. The brewery according to claim 13 or 14, wherein the first converter stage (3a) and / or the second converter stage (3b) is further configured for cell disruption (35).

16. The brewery according to claim 13, 14 or 15, wherein the biomass conversion plant (3) further comprises: a first separation unit (38) for separating the protein hydrolysate (6a) by means of separation, in particular centrifugal separation, and / or by means of membrane filtration, in particular ultrafiltration; and / or a second separation unit (42) for separation, in particular centrifugal separation, and / or for membrane filtration, in particular ultrafiltration, with a downstream ion exchanger (44) for separating a nutrient and fertiliser solution (45) containing the mineral fertiliser (6b).

17. The brewery according to claim 16, wherein a purification unit (48) for purifying (37a) the protein hydrolysate (6a) is associated with the first separation unit (38) and in particular connected downstream, in particular in the form of a unit for protein precipitation and subsequent filtration and / or centrifugal separation of precipitated peptides and / or amino acids and / or in the form of a unit for chromatographic separation.

18. The brewery according to at least one of claims 13 to 17, further comprising at least one gas storage (10) for the intermediate storage of biogas (7) obtained and / or a heat storage tank (11) for the intermediate storage of heat (12) obtained from the biogas and / or an electrical charge storage (13) for the intermediate storage of electrical current (14) obtained from the biogas in the combined heat and power plant (4).

19. The brewery according to at least one of claims 13 to 18, further comprising a mechanically controllable gas distributor (15) for the gradual distribution of the biogas (7) obtained to a first portion (7a) to be stored internally in a gas storage (10) and / or a second portion (7b) to be fed into an external gas network and / or a third portion (7c) to be burnt in the combined heat and power plant (4) and / or a fourth portion (7d) to be burnt internally in a boiler (16), and furthermore with a control device (17) for controlling the gas distributor (15) as a function of a heat and / or electricity requirement of the brewing plant (2) determined in particular as a function of operation.

20. The brewery according to at least one of claims 13 to 19, wherein the first converter stage (3a) can be controlled separately by machine with respect to the separation of protein hydrolysate (6a), and in particular with respect to an upstream separation of a protein-containing fraction (6c) resulting from the cell disruption, and the second converter stage (3b) can be controlled separately by machine with respect to the separation of mineral fertiliser (6b).