METHOD FOR ENERGY-EFFICIENT DRYING OF GERMINATED SEEDS AND DEVICE FOR CARRYING OUT THE METHOD

Description

Technical area

[0001] The invention relates to the field of industrial malt production, also called malting, and to industrial plants for the industrial production of malt from grain or, more generally, to industrial kilns for drying material to be dried (kilns). In particular, the invention relates to a method for drying green malt in an industrial kiln using one or more speed-modulated fans, wherein the fan provides an air mass flow through a bed of green malt to be dried. Kilns are devices for dehydrating and / or drying foodstuffs and consumer goods using heat. Kilns are normally classified according to the material to be dried, such as grain kilns, malt kilns, hop kilns, but also other kilns such as kilns for dried fruit, tobacco, shrimp, wood drying, seed kilns, or linen / flax kilns for fiber production (clothing, rope making).The present invention relates generally to energy-optimized kilns and kiln processes in the diverse aforementioned fields of application. In particular, however, the invention relates to energy-efficient malt kilns for kilning green malt, in which the green malt is piled up on a stationary or moving tray floor into a layer of predetermined height, through which an air stream, in particular a warm air stream, flows until the layer or a partial layer adjacent to the tray floor has reached a predetermined degree of dryness, whereupon this layer / partial layer is removed from the tray floor. In the case of a partial layer, the remaining partial layer is held on the tray floor, e.g. by redirection, and continues to be exposed to the air stream. The air stream is generated by an appropriately mounted fan. Background of the invention

[0002] Kilns have long been known devices for dehydrating and / or drying foodstuffs and other goods, such as linen or flax, using warmth or heat. Kilns typically consist of a locally confined area (drying chamber) which allows good air circulation. For certain applications, the kiln includes a wooden or wire grate with heating options for drying or roasting fruit, seeds, grain, hops, etc. However, the construction of the kiln differs depending on the application. Kilns are therefore typically divided according to the product to be dried, such as grain kilns, malt kilns, hop kilns, but also kilns for dried fruit, tobacco, shrimp, for wood drying, seed kilns or even linen / flax kilns for fiber production (clothing, rope making). The malt kiln, for example, is used for malt production.In malt production, the green malt is dried on the kiln as the third processing step after soaking and germinating, i.e., kilned. The heat and the associated removal of moisture not only make the malt storable, but also give it its typical (malty) aroma. The malt kiln consists of a close-meshed wire mesh or a slotted sheet, the so-called horde, on which the green malt is stacked. Hot air flows through the material to be dried from below, thus removing the moisture. In modern malthouses, the air is typically heated indirectly, for example by air heated directly by oil or gas burners, which transfers the heat energy to the air flowing through the green malt via a heat exchanger. Through indirect firing, the malt remains free from the pollutants and off-flavors of fossil fuels, and the formation of nitrosamines is minimized. Direct firing is typically used, for example,used to produce aromatic specialty malts. For example, smoked malt, which is used for smoked beer, is produced using a beechwood or, more rarely, an oakwood fire under the kiln. For whisky malt production, peat is burned under the kiln, which imparts a phenolic note to the malt and the resulting whisky. Recently, beers have also been increasingly produced with whisky malt. Another example is the hop kiln. Hops have a water content of 75-84% at harvest and, to maintain their storability, must be dried to a moisture content of 9-10% immediately after harvest. Depending on the variety and the size of the kiln, the drying time takes approximately 3-5 hours. For optimal drying results, a drying temperature of 62-68°C with a bed height of 20-35 cm and an air velocity of 0.30-0.45 m / s is aimed for in the hop kiln.In another example, grain kilning, the main purpose of kilning is also to preserve the grain. Since grain can only be safely stored below 14% moisture content, but can be threshed at a higher moisture content depending on the weather, the moisture must be removed by drying. If the grain is stored in conditions that are too humid, it will become infected with fungi and pests. Moisture in the grain can also cause spontaneous combustion. However, during later milling of the grain, it may be necessary to re-wetting it to 16-17% moisture content, depending on the glassiness of the grain, as the dry hull would splinter too much during milling and make it difficult to separate the bran from the flour. Another desired effect of grain kilning can be the creation of a roasted aroma when roasting the grain.A well-known product that derives its typical flavor from kilning is green spelt, the grain of spelt, which is harvested at a semi-ripe stage and immediately artificially dried. As discussed above, kilning is therefore of great importance in the industrial production of food, but also for other industrial goods that require a drying or dehydrating process.

[0003] In malt preparation, the process comprises the following three operations, namely (i) steeping, which involves placing and steeping in steeping containers, adding seeds and water, and then transporting the wet germination material to germination boxes, (ii) germination of the grain (emergence of the seeds), and (iii) kilning, i.e. the termination of germination by removing water as an artificial intervention in the germination process. The last step is carried out by means of a malt kiln. In malt kilns for the kilning of green malt, the green malt is piled up in the kiln room on a stationary or moving tray floor to a layer of a predetermined height, which is passed through by an air stream, in particular a warm air stream, until the layer or a partial layer adjacent to the tray floor has reached a predetermined degree of dryness, whereupon this layer / partial layer is removed from the tray floor. In the case of a partial layer, the remaining partial layer is, for example,by diverting it onto the tray floor and further exposed to the air flow. The air flow is typically generated by a suitably mounted fan, the kiln fan. The tray floor is permeable to air and gas and consists, for example, of a close-meshed wire mesh or a slotted sheet. The kilning processes known in the prior art for malt preparation, for example, run in batches, with batch after batch being treated one after the other on the tray floor in the kilning chamber. Each batch is typically applied evenly to the tray floor in the form of a layer of green malt and kilned there to a specified degree of dryness. The finished kiln-dried malt is then cooled and subsequently removed from the tray floor and transported away. An average target moisture content of 4 to 5% is usually assumed for the malt grains of the finished kiln-dried malt. Other target moisture levels can of course also be defined.

[0004] The use of speed-modulated fans to generate an air mass flow through the drying bed of green malt onto the tray floor of kilns, particularly malt kilns, is well known. A heated air mass flow is passed through the drying bed by a fan, thereby removing moisture from the drying material. On the downstream side, the air mass flow is typically saturated with approximately 100% moisture in a first phase until the drying material has reached a moisture content of approximately 20% or less. This is followed by a further drying phase until a predetermined residual moisture content of the drying material is reached. Depending on the kiln design, different types of fans are used. Fans are flow devices used to move air and build up pressure.Typically, axial fans are used for low and medium pressures, while centrifugal fans are used to generate higher pressures. Axial fans for generating high displacements and low pressures are typically characterized by long blades and small hub diameters. If higher pressures are to be generated with axial fans, impellers with larger hub diameters are required. The drive motors can either be integrated into the impeller hub (external rotor motor) or motors with a flanged blade can be used. Centrifugal fans are known, for example, as casing fans or as free-running impellers. Basically, a distinction can be made between impellers with forward-curved blades for high displacements at medium pressures and low noise levels, and impellers with backward-curved blades for high pressures in special systems. The drive of the impellers can, for example,Direct drive or V-belt drive. Typical parameters for selecting a fan are the desired flow rate (m³ / h), the static pressure increase (Ps in Pa), the noise level (dB (A)), and / or the temperature. To provide a flow rate and build pressure, mechanical, electrical, and flow-related losses occur in the fan, which contribute to the fan's energy efficiency.

[0005] Green malt consists of germinated grain from seeds such as cereals, pseudo-cereals, legumes, and the like, particularly barley, rye, or wheat, which is obtained by steeping and germination, for example, in a closed area. Generally speaking, the process involves germinated grain, which is obtained from viable, bioactive grain by steeping and germination, whereby steeping can be repeated several times. In malting processes, the aim of steeping and germination is typically to achieve the best possible malt quality with the highest possible weight yield within a corresponding production time. The green malt is then dried or kilned in conventional, industrial malting plants on tray kilns from a drying material moisture content of around 38-46% to a desired final product moisture content of around 3-6%, which completes the germination process.The primary purpose of this drying process is to make the malt storable and to induce various chemical changes in the malt by removing the water. For this purpose, heated drying gas is ventilated through the green malt, which may be stacked on one or more trays. Ambient air, heated by an upstream heating system, is commonly used as the drying gas. Another well-known option is to pass combustion gases mixed with ambient air directly through the green malt.

[0006] In the process of drying or kilning malt, which is used, for example, in beer production, it is of utmost importance not only to achieve targeted drying of the green malt, but also to influence certain malt properties through defined temperature control of the drying air, which influence the quality and flavor of the final product during the subsequent brewing process. In addition to these technological requirements, economic parameters must also be considered to ensure that the kilning process is as efficient as possible in terms of both energy consumption and operating effort. Furthermore, conditions must be created for the optimal integration of energy-saving components into the corresponding systems.

[0007] This task is solved using various kiln systems, depending on the individual assessment of the economic and technological constraints. Single-tray and double-tray kilns, as well as continuous kilns, are well-known. In addition to these purely static systems, in terms of the material being dried, dynamic systems with continuous malt conveyance have also been developed during the years of high energy prices. These three kiln types are described in detail in the state of the art, for example, in "Die Technologie der Malzbereitung" (The Technology of Malt Preparation) by Schuster / Weinfurtner / Narziss or in the patent DE A-3224471.109.

[0008] The factors that determine the drying process are in particular the mass of the material to be dried, the moisture content of the material to be dried, the temperature of the ambient air used, in particular the supply air, the humidity of the ambient air used, in particular the supply air, the temperature of the heated drying air, the temperature of the downstream, i.e. exhaust air side, air mass flow, the humidity of the downstream air mass flow, in particular the absolute exhaust air humidity during the withering, as well as the mechanical power of a fan driving this air mass flow.

[0009] As discussed above, malt production involves the following steps: (1) Pre-drying the grain; for storage, the grain's moisture content must not exceed 15%, so it may be necessary to dry the grain before storage. Such a drying process can be achieved by ventilating a grain silo. Of course, the grain harvest can also be adjusted to a desired moisture content, which would eliminate the need for the pre-drying step in question here; (2) Soaking the grain; for soaking, the grain is moistened to such an extent that the moisture content of the grain rises to up to 46%.The steeping step usually lasts 1 to 2 days, whereby the electrical energy consumption of the process systems involved is small compared to subsequent drying steps; (3) The germination of the grain; the steeped grain germinates within 3 to 5 days at a moisture content of approximately 38 to 46%, whereby this moisture content is ensured over the duration of this step by means of air humidification and / or spraying with water, and uniform germination occurs by regularly turning the germinated material. The electrical energy consumption in this step of germination is higher than in the preceding steeping, but still considerably lower than in the subsequent drying steps. The result after germination is what is known as green malt, which as such cannot be stored; and (4) The drying of the grain (kiln), i.e.In malt production, the green malt is dried on a kiln to ensure possible subsequent storage and transportability. The kilning process produces the colorings and aromas typical of malt. During the kilning process, the green malt is dried from a moisture content of 38 to 46% to a single-digit value of 3 to 8%. This takes place in two steps: During the first drying phase, the withering, the temperature of the exhaust air remains relatively constant, with the air flowing out of the kiln being almost 100% saturated with moisture. The heat energy required for withering is primarily used to evaporate the moisture on the surface of the green malt, under the husk, and in the easily accessible outer layers of the grain, thereby preserving the enzymes present in the germ.In the second phase, kilning, the temperature rises significantly even within the grain, and the water is gradually drawn out of the grain through capillary action. The air downstream of the kiln is no longer 100% saturated with moisture during this stage. The temperature and duration of this second phase determine the malt color. The higher the temperature and the longer the kilning, the darker the malt and the malted grains become as a result of the malting process.

[0010] The different consumption values ​​for malt drying arise from the fact that, for technological reasons, the drying process is divided into two phases, which differ primarily in terms of the air intake temperatures. Green malt for brewing purposes arrives at the kiln with a moisture content of 38-46% and, in the first phase, known as simmering, is dried to a moisture content of approximately 20% or less under gentle conditions at temperatures around 60°C. During this phase, the malt grain surface remains moist, so that the kiln air leaves the malt bed practically saturated with water vapor. This phase can last 10 to 24 hours, depending on the kiln type, and is characterized by optimal utilization of the drying potential of the kiln air.In the second phase, the so-called kilning, the water content in the finished malt should be below 3-8%. During the final hours, again for technological reasons, the kilning air temperature should be between 80 and 90 °C, in some cases up to 110 °C. The resulting insufficient utilization of the drying potential is indicated by a significant increase in the temperature of the used kilning air. While the exhaust air temperature is still around 28 °C at the end of the simmering period, it rises to values ​​between 70 and 80 °C by the end of the kilning phase.

[0011] The drying step typically requires the greatest amount of energy, both in the form of heat energy for the air flow to the kiln and in the form of electrical energy for ventilating this air through the kiln. The amount of electricity required for ventilation is particularly significant here, as the air mass flow is known to be cubed to the energy consumption (RPM ≈ P 3<, where RPM = Revolutions Per Minutes, i.e., 60rpm=1s -1< in units of rotational speed n). However, this air mass flow is only linearly dependent on the fan speed (RPM ≈ V air ).This means that, for example, a reduction in the fan speed n from 100% to 90% can mean a 27% reduction in fan power consumption, or a reduction in the speed from 100% to 80% can result in a reduction in fan power consumption of around 49%. However, it should be noted that while a reduction in the fan speed reduces the fan power consumption by 49%, the extension of the simmering time means that the reduction in power does not translate directly into the energy consumption savings of the entire process. In the example given (reduction in fan power consumption by 49%), the reduced fan power consumption, taking into account the extended simmering time, reduces the total electrical energy requirement of the fans by approximately 39%.In other words, it is typically easier to specify the reduction in fan power, as this is directly calculable. However, it should be noted that the energy requirement will be lower due to the relationship mentioned above (RPM ∼ VL; RPM ∼ t; RPM ∼ P 3<). However, the moisture content of less than 10%, e.g., 3-8% or less than 5% of the malt grains after kilning, is generally the key objective.

[0012] How Figure 1 As illustrated, many kilns are typically operated in a specific rhythm (e.g. 20h, 24h, 32h, 36h or 48h etc.), ie: every day at approximately the same time, the entire amount of green malt to be kilned is loaded onto a rack (only applies to a multiple of 24h, otherwise the start and end of the kilning process moves accordingly), while previously the pre-dried (slaked), then fully dried (kiln-dried) and finally cooled malt was unloaded. Figure 1The different phases include (i) loading (2-3 hours), (ii) withering (8-12 hours), (iii) heating-up (3-4.5 hours), (iv) curing (3.5 hours), (v) cooling (0.5-2 hours), and finally (vi) unloading (2-3 hours). In the case of two-tray kilns operating on a 24-hour cycle, it should be noted that the entire quantity of green malt to be kilned is loaded onto one tray at approximately the same time each day, while the pre-dried (withered) malt from the previous day is ready for final drying (kiln drying) on ​​the other, second tray. Thus, a batch is kilned in a 2 x 24 = 48-hour cycle. This, of course, assumes that each horde can hold the same full amount of green malt. Figure 2shows another drying scheme for a continuous single-tray kiln of the prior art. Here, the temperature under the tray is continuously increased until the desired moisture content of 3 to 8% of the malt grains is reached. It should be mentioned that there are other options for double-deck kilns than the one mentioned above, e.g. the material remains on the tray where it is and instead of being transferred to the second tray, the air flow is switched from the first tray to the second tray and vice versa. The present invention, however, can be applied regardless of the drying option chosen, and therefore relates to both single-tray kilns and all possible two-tray kilns, particularly when they are operated at a certain rhythm.

[0013] How Figure 3As further shown, the total kilning process duration varies with the selected fan speed. At a speed of n=100%, the kilning time t is shorter than at a reduced speed of n=90%. As an example, the case presented here is one in which a maximum kilning time t max specified by the industrial malting plant is achieved precisely when the fan is operated at a speed of n=80% during the simmering, heating, and kilning stages. This results in the aforementioned saving of approximately 39% in electrical energy for the fan.While it is conceivable to reduce the fan speed to values ​​below 100% in order to reduce energy consumption, this would result in a conflicting objective: the kilning step, given the target moisture content of 3 to 8% of the malt grains, would require a corresponding extension of this step, which would entail a corresponding increase in time and could thus conflict with the other constraints of industrial malting plants. It should be noted that a reduction in fan power or its speed does not necessarily have to be a constant reduction, but rather depends on boundary parameters such as measured fluctuating initial and final product moisture contents, changing weather conditions, quality measurement parameters, and / or unwanted process extensions, etc.Other constraints of such malting plants include grain storage capacity, germination duration, and the maximum possible drying or kilning time, which encompasses loading the kiln, wilting, heating, drying, and unloading. This drying time is further determined by plant-typical or plant-specific loading times for the kiln and the maximum possible drying time, which results in a latest unloading time for the kiln, by which the kiln must be free for a subsequent malt batch. It should be noted that, as a rule, not only the kiln itself is time-fixed in these processes, but also the upstream process steps, such as steeping and germination.The possible energy savings by reducing the fan speed therefore depend on the maximum possible, plant-specific drying time and the associated times for loading and unloading, under the given basic condition of the resulting moisture content of the malt grains or the so-called kilned malt.

[0014] Table 1 schematically illustrates a process diagram of a single-tray high-performance kiln operating at a 24-hour cycle, in this example for the production of Pilsner malt (example). The process diagram in Table 1 can also serve as an exemplary control GUI (graphical user interface) of a state-of-the-art kiln, comprising (i) static control: manual adjustment of the fan speed during kilning, (ii) triggering the next process step when predefined thresholds are reached, and (iii) withering at a constant fan speed of 100%. In this example, the total time is 23.5 hours and the drying time is 18 hours. Process step 0 1 2 3 4 5 6 7 Process section Loaded Smoldering Heating up Drying Cool Unloading Max. total duration (h) 2 1 12 2.5 3 1 2 Max. step duration (min) 120 60 180 540 240 60 60 120 Min. step duration (min) - 60 150 360 240 45 30 - Process temperature (°C) - 55 55 60 85 85 0 - Switching criterion: exhaust air temperature (°C) - - - - - - <50 - Switching criterion exhaust air humidity (%) - - - <80 - - - - Fan speed (%) - 60 100 100 75-100 50-70 100 - Return air proportion (%) - 0 0 0 25-50 50-75 0 0

[0015] From the publication GB 2 287 527 A, a method for malting grain and an associated malting plant are known. During the drying step in the kiln, the necessary air mass flow through the drying material bed is provided depending on the air humidity detected downstream of it. This means that this air mass flow is controlled by means of a fan speed modulation in such a way that a reduction in electrical energy consumption for the fan used can be achieved. However, the current state of the art fails to acknowledge that the sole speed modulation depending on the downstream air humidity can result in only a limited, adjustable reduction in electrical energy consumption.Even if - as proposed here - the described speed modulation of the fan may be accompanied by a reduction in electrical energy consumption, this does not yet achieve consumption optimization over the entire drying time.

[0016] Document GB 2 287 527 A discloses a method for the energy-efficient drying of germinated seeds in a kiln, which comprises fan speed modulation based on the moisture content of the material to be dried. Furthermore, DE 34 07 685 C1 describes a method for drying germinated seeds in a kiln using a fan for passing an air mass flow through a bed of material to be dried, wherein the drying is carried out during a predetermined maximum drying time (15 hours). Finally, documents US 2020 / 263923 A1 and US 2015 / 354895 A1 describe methods for the energy-efficient drying of grain in a kiln using a fan for passing an air mass flow through a bed of material to be dried. A grain moisture content and an ambient humidity of the ambient air used for the air mass flow are recorded.During drying, the moisture content of the dried product is monitored up to a specified limit. Summary of the invention

[0017] It is an object of the present invention to provide a method for the most energy-efficient drying of green malt and a kiln for carrying out the energy-efficient drying of green malt, thereby eliminating the aforementioned disadvantages of conventional malting systems. In particular, it is an object of the invention to provide an optimization of electrical energy consumption, particularly with regard to the regulation of the air mass flow by means of ventilation through the drying material bed.

[0018] According to the present invention, these objects are achieved in particular with the features of the independent claims. Furthermore, further advantageous embodiments can be derived from the dependent claims and the associated descriptions.

[0019] According to the present invention, the above-mentioned objects for a kiln and corresponding method for energy-efficient drying of green malt in a kiln with the aid of a speed-modulated fan for passing an air mass flow through a drying bed of the green malt are achieved by carrying out the drying during a predetermined maximum drying time (t max ), by recording a grain moisture content (Hg) and a grain mass (Mg) of a grain which, after soaking and germination, forms the basis for the drying bed of the green malt, by recording an ambient air humidity (HI / Hla) of an ambient air used for the air mass flow, by recording a number of weather forecast data (W1, W2) at least with regard to the ambient air humidity (HI / Hla),that during drying, the moisture content of the green malt (Ht) is monitored up to a predetermined limit value (Gt), and that based on the grain moisture content (Hg), the grain mass (Mg), the ambient humidity (HI / Hla), the number of weather forecast data (W1, W2) regarding the ambient humidity (HI), and based on the moisture content of the green malt (Ht) (2), the fan speed is modulated such that the predetermined maximum drying time (t max ) is reached and / or maintained. The ambient humidity (HI) includes the absolute air humidity. If the ambient humidity (HI) only includes the relative air humidity, the air temperature must also be recorded as a weather forecast.so that, together with the predicted relative humidity, the predicted absolute humidity can be generated using the device. To distinguish between relative and absolute exhaust air humidity, it should be noted that absolute humidity describes the total amount of water contained in a specific room volume. Absolute humidity is usually expressed in grams per cubic meter (g / m 3 ). Air at 30°C can absorb 31 grams of water per cubic meter (31 g / m 3 ), while air at 5°C can only absorb 7 grams of water per cubic meter (7 g / m 3 ). Relative humidity, on the other hand, indicates the percentage of air that is saturated with water (vapor). The general rule is: the warmer the air temperature,the more water it can absorb. At 100% relative humidity, the air is completely saturated with water (vapor). At 50% relative humidity, the air is half saturated with water (vapor). If 100% relative humidity is exceeded, the excess moisture turns into condensation. Regarding the absolute exhaust air humidity during the withering process, the system according to the invention can predict this exhaust air humidity based on weather data and the exhaust air humidity at the beginning of the drying process. Alternatively, it can include a fixed, adjustable or otherwise predefined empirical value.

[0020] In this context, the maximum drying time is understood to be the total residence time of a drying product in a drying kiln. The drying time between loading and unloading the drying product into and out of the kiln includes the steps of smoldering, heating, drying, and cooling. Loading and unloading, as well as cooling, are essentially determined by the mass or volume of the drying product, with cooling typically also strongly dependent on the outside air parameters, such as temperature. Other factors only slightly influence the loading and unloading times or cooling times, so that these times are hardly influenceable with regard to a specified maximum drying time or energy consumption optimization.The sequential steps of simmering, heating, and drying, however, are significantly influenced by the aforementioned boundary conditions, namely the grain moisture content, the grain mass, the ambient humidity, the number of weather forecast data regarding the ambient humidity, and the moisture content of the green malt as it is dried. This moisture content of the green malt as it is dried largely determines the process times for simmering, heating, and drying. It should be noted that, in a first step toward energy optimization, only the simmering part can be considered a temporally variable component, with the heating and drying stages being considered fixed in time. As a variant, the entire process, including simmering, heating, and drying, can also be included for energy optimization.

[0021] The invention has the advantage, among other things, that speed modulation of the ventilation through the drying material can be used in such a way that the entire drying time can be utilized and / or adhered to as far as possible while maintaining the desired moisture content of the green malt, and the energy efficiency of the device is optimized. This means that the speed of the fan for the necessary air mass flow during withering, heating and drying is modulated in such a way that the required moisture content of the green malt is achieved when the end of the predetermined maximum drying time is reached. As already mentioned, as a variant, the speed can be modulated only during withering. For further optimization, the heating and / or drying can also be included in the modulation.This means that the work steps of wilting, heating and drying are extended in time, which means that a reduction in the speed of the fan for the air mass flow is possible and thus a significant saving in electrical energy. Another advantage is that the present consumption optimisation not only brings about a simple reduction in consumption, but also its consumption distribution over time, namely the consumption distribution of electrical energy over the - above- mentioned - maximum possible, plant-specific drying or kilning time, which smooths out the electricity consumption across all work steps in industrial malting plants, which ultimately also means more sustainable use of resources. Electricity savings and savings in the power consumption of the fan through the present invention are clear. However, the invention also results in further savings in energy consumption, in particular for example thermal energy savings.For example, cooling of the system is prevented through better temporal utilization, or savings are achieved through the resulting larger specific heat exchanger surface area at reduced volume flows. Furthermore, the method according to the invention makes it possible to predict the temporal distribution of energy consumption, particularly during the smoldering, heating, and drying steps. Such energy consumption forecasts are now also linked to significant economic aspects, creating strong incentives to sustainably smooth and / or reduce energy consumption.Ultimately, the boundary conditions at the respective location of the industrial malting plant used also play a relevant role; these boundary conditions include, among other things, electricity supply contracts with negotiated peak consumption values, as well as the regionally specific climatic conditions of the environment or the intrinsic properties of the grain to be malted itself. A further advantage of utilizing the maximum drying time in industrial malting plants is that they cool down less due to shorter downtimes between batch changes. Thus, residual heat remains in the malting plant due to the considerable heat capacity, thus reducing the energy required to heat up the malting plant before the start of the next drying phase. Short description of the drawings

[0022] The present invention will be explained in more detail by way of example with reference to the drawings in which it is illustrated: How Figure 1 shows a diagram illustrating how many kilns are typically operated in a certain rhythm (e.g. 20h, 24h, 32h, 36h or 48h etc.), ie every day at approximately the same time the entire quantity of green malt to be kilned is loaded onto a trough, while previously the pre-dried (slaked), then the fully dried (kiln-dried) and finally the cooled malt was unloaded. Figure 1The different phases include (i) loading (2-3 hours), (ii) withering (8-12 hours), (iii) heating-up (3-4.5 hours), (iv) curing (3.5 hours), (v) cooling (0.5-2 hours), and finally (vi) unloading (2-3 hours). In the case of two-tray kilns operating on a 24-hour cycle, it should be noted that in the case of a two-tray kiln operating on a 24-hour cycle, the entire quantity of green malt to be kilned is loaded onto one tray at approximately the same time each day, while the pre-dried (withered) malt from the previous day is ready for final drying (kiln drying). In this case, a batch is actually kilned in a 2 x 24 = 48-hour cycle. This, of course, assumes that each horde can hold the same full amount of green malt. It should be mentioned again that there are other options for double-deck kilns besides the one mentioned above, e.g.That is, the product remains on the tray it is on, and instead of being transferred to the second tray, the air flow is switched from the first tray to the second tray and vice versa. However, the present invention can be applied regardless of the kiln type chosen, thus it applies to both single-tray kilns and all possible two-tray kilns, especially when operated at a specific rhythm.

[0023] Figure 2shows an example diagram that schematically illustrates another drying scheme for a continuous single-tray kiln of the state of the art. The temperature under the tray is increased continuously or step by step, e.g. in time stages, until the desired moisture content of 3 to 8% of the malt grains is reached. Withering for 2 hours at 50 °C and 2 hours at around 57 °C and drying for around 5.5 hours at 62 °C, around 2 hours at 68 °C, around 1.5 hours at 72 °C, around 2 hours at 80 °C and around 4 hours at 85 °C, i.e. to an exhaust air temperature of approx. 80 °C. Heating up from 65 to 80 °C for around 4 hours, drying for around 5 hours at 80-85 °C. This results in a total duration of the drying process, i.e. withering and drying, of 19 hours. As mentioned, during kilning, the green malt is dried from a moisture content of 38 to 46% to a single-digit value of 3 to 8%. This occurs in two sub-steps: simmering and drying. During simmering, the temperature of the exhaust air remains relatively constant (see 。 Figure 2 ), whereby the air flowing out of the kiln is saturated with almost 100% moisture. In the second phase of drying, the temperature also rises sharply in the grain interior and the water is gradually extracted from the grain via the capillary effect. The air flowing out of the kiln is no longer 100% saturated with moisture at this stage (see Figure 2 ).

[0024] Figure 3shows an example diagram that schematically illustrates how the entire kiln-drying process duration changes with the selected fan speed. At a speed of n=100%, the drying time is shorter than at a lower speed of n=90%. As an example, the present case also shows a case in which a maximum drying time specified by the industrial malting plant is achieved precisely when the fan is operated at a speed of n=80% during the withering, heating, and drying stages; this enables the aforementioned saving of around 39% in electrical energy for the fan. Again, it should be noted that while a reduction in the fan speed reduces the fan power consumption by 27% or 49%, the extension of the withering time does not result in a 1:1 reduction in power consumption resulting in energy savings for the entire process.In the example given (reduction in fan power consumption by 49%), the reduced fan power consumption, taking into account the extended withering time, reduces the total electrical energy requirement of the fans by approximately 39%. In other words, it is typically easier to specify the reduction in fan power, as this is directly calculable. However, it should be noted that the energy requirement will be lower due to the relationship mentioned above (RPM ∼ VL; RPM ∼ t; RPM ∼ P 3<). Generally, however, the moisture content of less than 10%, e.g., 3-8% or less than 5% of the malt grains after kilning is the key ultimate goal. Figure 3shows three cases, namely an initial situation (Case 1 (initial)), a Case 2 and a Case 3. In the initial situation the fan is operated at 100% speed, the withering time is 10 hours (withering time = 10h) and the total kiln time is 17 hours (total kiln time 17h), whereby the energy consumption is 5,500 kWh el. In Case 2 the fan is operated at 90% speed, the withering time is 11 hours, the total kiln time is 18 hours and the energy consumption is 4,455 kWh el . This corresponds to a reduction in energy consumption of -19% of the total electrical energy consumed by the fan, whereby the power consumption of the fan is reduced by 27%, but the withering time and the kiln time are each extended by 1 hour.In case 3, the fan is operated at 80% speed, the withering time is 12 hours and the total drying time is 19 hours, with energy consumption being 3,420 kWh e. This corresponds to a reduction in energy consumption of -38% of the total electrical energy consumed by the fan, whereby the fan's power consumption is reduced by 49%, but the withering time and the drying time are each extended by 2 hours. Case 3 corresponds to the maximum possible extension of the drying time within the process without affecting the fixed scheduled times of the process steps, in particular the drying time. In other words, longer drying times at lower fan speeds reduce energy consumption. The device and method according to the invention allow the fan speeds to be adjusted so that optimal utilization of the available drying phase is achieved at the maximum possible time.

[0025] Figure 4 shows a diagram which schematically illustrates that the withering and corresponding times are not constant, but are influenced by, for example: (i) weather conditions (e.g. absolute humidity of the fresh air / supply air), (ii) initial moisture content of malt, (iii) batch load, and (iv) air mass flow: dependent on fan speed, batch size, load quality. Other influencing variables can include, for example, drying temperature, exhaust air humidity, etc. It should be noted that the state of the art cannot take into account variables that have not been influenceable to date, such as the development of air humidity over time, e.g. based on weather forecast measurement parameters.

[0026] Figure 5 shows a diagram which schematically illustrates that the resulting total drying times are particularly dependent on (i) loading time (step 1), (ii) smoldering (step 3) highest impact on the variability, and (iii) final drying (step 10)

[0027] The Figure 6 shows a diagram which schematically illustrates the correlation of the fan speed (n) with: (i) linear with the air mass flow: n ∼ ṁA, and (ii) to the third power with the power consumption: n ∼ (PF ) 3< . A reduction in the fan speed by 10% extends the drying time by 10%, a reduction in the fan speed by 10% reduces the fan power by 27%, while, for example, a reduction in the fan speed by 20% extends the drying time by 20% and a reduction in the fan speed by 20% reduces the fan power by 49%.

[0028] The Figure 7schematically illustrates an architecture of a possible realization of an embodiment variant for the energy-efficient drying of green malt 2 in a kiln 1 with the aid of a speed-modulated fan 3 for passing an air mass flow 4 through a drying material bed 2.1 of the green malt 2. The drying is carried out during a predetermined maximum drying time (t max ). Detailed description of preferred design variants

[0029] The Figure 7 schematically illustrates an architecture of a possible realization of an embodiment variant for the energy-efficient drying of green malt 2 in a kiln 1 with the aid of one or more speed-modulated fans 3 for passing an air mass flow 4 through a drying material bed 2.1 of the green malt 2. The drying is carried out during a predetermined maximum drying time (t max ).

[0030] A grain moisture content (Hg) and a grain mass (Mg) of a grain 2.2 are recorded. After steeping 5 and germination 6, the grain 2.2 forms the basis for the drying material bed 2.1 of the green malt 2. Using measuring sensors, an ambient humidity (Hl) of the ambient air 7 used for the air mass flow 4 is recorded. Additionally, for example, an absolute ambient humidity (Hla) of the ambient air 7 used for the air mass flow 4 can be recorded.

[0031] Weather data is recorded using measuring stations. Based on the weather data, a number of weather forecast data items (W1, W2) are recorded or generated, at least with regard to the ambient air humidity (H1). The number of weather forecast data items (W1, W2) can be generated or recorded, for example, with regard to at least the absolute ambient air humidity (H1a). The number of weather forecast data items (W1, W2) can be continuously, i.e., dynamically, generated or determined, for example, with regard to the absolute ambient air humidity (H1a), for the next 12 hours from the start of loading 8 of the kiln 1 and / or from the start of the kiln fan. The term "from the start of loading of the kiln" in this disclosure can include loading or presuppose that loading has been completed. The reason for this is that in certain design variants, even before the end of loading, e.g.Halfway through the loading time, the fan is already started and drying begins to avoid any loss of time. During drying, the moisture content (Ht) of the green malt 2 is monitored up to a specified limit (Gt). The limit (Gt) of the moisture content (Ht) of the green malt can be a maximum of 3-8%, e.g., 5%. Other values ​​are also possible. For example, the target water content after the simmering phase can also be defined, for example, in a range of 12-20%.

[0032] Based on the grain moisture content (Hg), the grain mass (Mg), the ambient air humidity (HI), the number of weather forecast data (W1, W2), the speed of the fan 3 is modulated with regard to the ambient air humidity (HI) and based on the drying material moisture content (Ht) of the green malt 2 such that the specified maximum drying time (t max ) is reached and / or maintained. The grain moisture content (Hg), the grain mass (Mg), the ambient air humidity (HI), the number of weather forecast data (W1, W2) with regard to the ambient air humidity (HI) and the drying material moisture content (Ht) of the green malt (2) can be recorded, for example, by means of an intelligent system unit 15 of the kiln, with which the speed of the fan 3 is modulated such that the maximum drying time (t max ) is reached and / or maintained and an energy consumption forecast (Ev) is determined.

[0033] For drying the green malt 2, for example, the fan 3 for generating the air mass flow 4 through the drying material bed 2.1 of the green malt 2 can be bidirectionally connected to the intelligent system unit 15 via a data transmission network 16, wherein the intelligent system unit 15 is connected to a grain moisture content sensor 17 and / or a grain mass sensor 18 and / or an ambient humidity sensor 19 and / or a number of sensors for weather measurement data and a forecast unit for generating the weather forecast data 20.1, 20.2 and / or a drying material moisture content sensor 21 of the green malt 2, wherein the intelligent system unit 15 further comprises an optimization means 15.1 for dynamically optimizing and / or adapting and / or learning work steps 8 - 14 for energy-efficient drying of green malt 2. For dynamic speed modulation of the fan 3, for example, the optimization means 15.1 of the intelligent system unit 15 can be connected via the data transmission network 16 to a speed actuator 3.1 of the fan 3 for the purpose of dynamic speed modulation of the fan 3. As a design variant, flap settings, e.g. of the supply air, exhaust air or, in the case of the pressure fans, can also be taken into account by the intelligent system unit 15 or used as input or output parameters. As described, the kiln is ventilated via an appropriately dimensioned fan. It draws air either from a fresh air shaft or from a return air duct and forces it into the pressure chamber above. From there, the air penetrates the material lying on the rack and is discharged into the exhaust air duct. This forms a common shaft with the return air duct. The air can be directed, for example, by a closing return air flap or a slide valve.The air flow through a fan ensures the most even ventilation possible, even at the same height of the material. Furthermore, the air flow can also be regulated by exhaust air dampers and / or flaps in the ducts in front of the fan. However, the most direct regulation option is via (or in addition to) the fan speed, for example, using frequency-controlled motors. This is automatically controlled by the intelligent system unit 15, for example, depending on the temperature difference between the upper malt layer and the incoming air. Figure 2shows an example diagram of such a process. Withering for 2 hours at 50°C and 2 hours at around 57°C and kilning for around 5.5 hours at 62°C; around 2 hours at 68°C; around 1.5 hours at 72°C; around 2 hours at 80°C, and around 4 hours at 85°C, i.e. to an exhaust air temperature of around 80°C. Heating up in 4 hours from 65 to 80°C, kilning for 5 hours at 80-85°C. This results in a total time of withering and kilning of 19 hours. At an exhaust air temperature of 40°C, for example, additional speed regulation can be used. The difference to the temperature inside the room can still be around 30°C at this time, for example. At an exhaust air temperature of 30°C, i.e. before the kilning process begins, a recirculation flap can be opened, for example. The return air content towards the end of the kilning period can then be, for example, 50-70%. As mentioned, during kilning, the green malt is dried from a moisture content of 38 to 46% to a single-digit value of 3 to 8%.This happens in the two sub-steps of wilting and drying: During wilting, the temperature of the exhaust air remains relatively constant (see . Figure 2 ), whereby the air flowing out of the kiln is almost 100% saturated with moisture. In the second phase of drying, the temperature also rises sharply inside the grain, and the water is gradually extracted from the grain via the capillary effect. The air flowing out of the kiln is no longer 100% saturated with moisture at this stage (see Figure 2 ).

[0034] As a variant, for example, the absolute exhaust air humidity can be determined during the withering process. The device can, for example, comprise a prediction module by means of which this exhaust air humidity as well as the exhaust air humidity at the start of the kilning process is determined using a forward-looking method based on measured weather data such as ambient temperature, air pressure, ambient humidity, etc. The prediction module can be implemented as a machine-learning unit which is learned in a supervised learning phase using a feedback loop for transmitting the corresponding measurement parameters. Alternatively, the measurement parameter patterns associated with a specific measured exhaust air humidity can first be recorded by means of classification by an unsupervised learning structure. These can be used directly to predict the exhaust air humidity or as input for the supervised learning structure.

[0035] As an embodiment variant, for example, an energy consumption forecast (Ev) of the kiln 1 can be generated for the work step of wilting 9 of the green malt 2. Likewise, for example, the energy consumption forecast (Ev) can be generated for a work step of heating 11 of the green malt 2 in the kiln 1. Furthermore, for example, the energy consumption forecast (Ev) of the kiln can also be determined or generated for the work step of drying 12 of the green malt 2. As a further embodiment variant, for example, a specific self-test can be carried out as a safety test using the device. The safety check can include the following implementation steps: (i) Checking whether the ambient conditions are positive and whether the implemented safety check structure can be applied; (ii) Checking / scanning the sensors: Detecting defined conditions, such asone of the two fans, one of the two burners, the temperature and the humidity sensor via KLN is faulty for more than 10 minutes during steps 0-1-2; (iii) Check the absolute fresh air humidity according to a defined limit trigger value: e.g., if for a variant it should not exceed 10 g / kg for stage 2, etc.; (iv) Check the duration of step 1: e.g., it should not exceed 2.5 hours; (v) Check the duration of step 2: e.g., it should not exceed 3 hours; (vi) Check the absolute delta humidity above the kiln AH fresh air: e.g., it should be more than 10 g / kg; (vii) Green malt content: e.g., check whether the content is < 45%; (viii) Termination of the process if one of the trigger criteria is not met. Risk buffers can also be provided as an implementation variant: (i) Is the calculation based on a mcafter wilting of 12% → more likely 15 to 18% (3-5% buffer); (ii) The fan speed can be limited, e.g. to 75%, to avoid a risk and to get out of the ideal range → If the generated predictions are correct in each case, the limit can be reduced; (iii) Stage 4 still runs at 100% fan speed → if under-drying actually occurs during wilting, compensation in stage 4 by high fan speed + rising temperatures is very likely: time buffer = 90 minutes (i.e. 180 min → 270 max); (iv) Maximum permissible wilting time is e.g. 9h → Then the e.g. a risk buffer can be regulated as maximum total kiln time = 21.5 h including loading time + 2h for cooling; (v) Calculations could e.g.based on 8.5h to increase the fan speed → additional buffer; (vi) the process can be started with malt batches (or other less sensitive batches) produced for food applications, where specifications are less critical than in brewing applications. The goal of the risk buffers is to minimize the risk of under-drying during the automated process. Reference list

[0036] 1 Kiln 2 Germinated seeds, e.g. green malt 21 Drying material bed 22 Grain 3 Fan 31 Speed ​​actuator of 3 4 Air mass flow 5 Steeping 6 Germination 7 Ambient air 8 Loading 9 Smoldering 10 Breakthrough 11 Heating 12 Drying 13 Cooling 14 Unloading 15 Intelligent system unit 15.1 Optimization means 16 Data transmission network 17 Grain moisture content sensor 18 Grain mass sensor 19 Ambient air humidity sensor 20 Sensors for weather measurement data (20.1, 20.2) 21 Drying material moisture content sensor 22 Grain storage 23 Steeping 24 Germination box 25 Malt silo 26 Weather station 27 Drying malt n Speed ​​of 3 in % Ht Drying material moisture content Gt Limit value of Ht Hg Grain moisture content Mg Grain mass HI, Hla Ambient humidity, absolute ambient humidity W1, W2 Weather forecast data from HI (may also include Hla) Ev Energy consumption forecast t Drying time t max Specified maximum drying time

Claims

1. Process for energy-efficient drying of germinated seeds (2) in a drying kiln (1) by means of a rotational speed-modulated fan (3) for directing an air mass flow (4) through a bed of drying material (2.1) for the germinated seed (2), wherein the drying is implemented for a specified maximum kiln time (tmax), characterized in that a grain moisture content (Hg) and a grain mass (Mg) of a grain (2.2) are detected, which constitutes a basis for the bed of drying material (2.1) of the germinated seed (2) after steeping (5) and germinating (6), an ambient air humidity (HI / Hla) is detected for an ambient air (7) used for the air mass flow (4), a plurality of weather forecast data (W1, W2), at least with respect to the ambient air humidity (HI / Hla) are detected, while drying, a drying material moisture content (Ht) of the germinated seed (2) is monitored up to a specified limit (Gt), and based on the moisture content of the grain (Hg), that the grain mass (Mg), the ambient air humidity (HI / Hla), the plurality of weather forecasts (W1, W2), with respect to the ambient air humidity (HI) and based on the moisture content of the drying material (Ht) of the germinated seed (2), a rotational speed modulation of the fan (3) is undertaken in such a way that the specified maximum kiln time (tmax) is reached and / or maintained.

2. Process for energy-efficient drying of germinated seeds (2) according to claim 1, characterized in that the germinated seed (2) comprises green malt.

3. Process for energy-efficient drying of germinated seeds (2) according to any one of claims 1 or 2, characterized in that an absolute ambient air humidity (Hla) of the ambient air (7) used for the air mass flow (4) is detected.

4. Process for energy-efficient drying of germinated seeds (2) according to claim 3, characterized in that the plurality of weather forecast data (W1, W2) with respect to the absolute ambient air humidity (Hla) are detected.

5. Process for energy-efficient drying of germinated seeds (2) according to claim 4, characterized in that the plurality of weather forecast data (W1, W2) with respect to the absolute ambient air humidity (Hla) for time duration defined from loading (8) of the kiln (1) and / or from the start of the rotational speed-modulated fan (3) are ascertained continuously.

6. Process for energy-efficient drying of germinated seeds (2) according to claim 5, characterized in that the defined time duration corresponds to a duration of a scheduled drying time.

7. Process for energy-efficient drying of germinated seeds (2) according to any one of claims 1 to 6, characterized in that the limit (Gt) of the moisture content of the drying material (Ht) of the germinated seed (2) is a maximum of 10%.

8. Process for energy-efficient drying of germinated seeds (2) according to claim 7, characterized in that the limit (Gt) of the moisture content of the drying material (Ht) of the germinated seed (2) is a maximum of 5% or between 5% and 7% or between 5% and 10%.

9. Process for energy-efficient drying of germinated seeds (2) according to any one of claims 1 to 8, characterized in that the detection of the moisture content of the grain (Hg), the grain mass (Mg), the ambient air humidity (HI), the plurality of weather forecast data (W1, W2) with respect to the ambient air humidity (HI) and the moisture content of the drying material (Ht) of the green malt (2) is done by means of an intelligent system unit (15), with which the rotational speed modulation of the fan 3 is done in such a way that the maximum kiln time (tmax) is reached and / or is maintained, and an energy consumption forecast (Ev) is ascertained.

10. Process for energy-efficient drying of germinated seeds (2) according to claim 9, characterized in that drying of germinated seeds (2) in the kiln (1) comprises at least withering (9) and curing (12) as two drying phases, wherein for the withering (9) of the green malt (2) in the kiln (1), the energy consumption forecast (Ev) is ascertained.

11. Process for energy-efficient drying of germinated seeds (2) according to claim 10, characterized in that drying of germinated seeds (2) in the kiln (1) comprises heating up (11) between withering (9) and curing (12), wherein for the heating up (11) of the germinated seed (2) in the kiln (1), the energy consumption forecast (Ev) is ascertained.

12. Process for energy-efficient drying of germinated seeds (2) according to any one of claims 9 to 11, characterized in that the energy consumption forecast (Ev) is ascertained for the curing (12) of the germinated seed (2) in the kiln (1).

13. Device for implementing the process according to any one of claims 1 to 12, characterized in that the drying of the germinated seeds (2) in the kiln (1) comprises at least loading (8), withering (9), breakthrough (10), heating up (11), curing (12), cooling (13) and unloading (14) as working steps, wherein for drying the germinated seed (2) the fan (3) for directing the air mass flow (4) through the bed of drying material (2.1) of the germinated seed (2) is connected bidirectionally to an intelligent system unit (15) via a data transmission network (16), wherein the intelligent system unit (15) is connected to a grain moisture content sensor (17), a grain mass sensor (18), an ambient air humidity sensor (19), a plurality of sensors for weather forecast data (20.1, 20.2) and a drying material moisture content sensor (21) of the germinated seed (2) and the intelligent system unit (15) further comprises an optimization means (15.1) for dynamic optimization and / or adaptation and / or learning of the working steps (8 -14) for energy-efficient drying of germinated seeds (2).

14. Device according to claim 13, characterized in that the optimization means (15.1) of the intelligent system unit (15) is connected by the data transmission network (16) to a rotational speed actuator (3.1) of the fan (3) for the purpose of dynamic rotational speed modulation of the fan (3).

15. Device for the implementation of the process according to any one of claims 1 to 14, characterized in that the moisture content of the drying material (Ht) of the germinated seed (2) is monitored up to a specified limit (Gt) via an inline moisture determination by means of a moisture device and / or a moisture sensor.

16. Device for implementation of the process according to any one of claims 10 to 15, characterized in that, during withering (9) the absolute exhaust air humidity is measured and / or ascertained.

17. Device for implementation of the process according to any one of claims 10 to 16, characterized in that the absolute exhaust air humidity during withering (9) is determined and / or measured based on measured weather data by means of a forecast module.

18. Device for implementation of the process according to any one of claims 1 to 17, characterized in that the exhaust air humidity at the start of kilning is determined and / or measured based on measured weather data by means of a forecast module.

19. Device for implementation of the process according to any one of claims 17 and 18, characterized in that the forecast module is realized as a machine-learning unit, which comprises as input parameter measurements weather data and / or ambient data measured and / or forecast according to the learning phase.