PROCESS FOR ENERGY-EFFICIENT DRYING OF GERMINATED SEEDS AND DEVICE FOR IMPLEMENTATION OF THE PROCESS

Abstract

A process and device for energy-efficient drying of green malt in a drying kiln using a rotational speed-modulated fan for directing an air mass flow through a bed of drying material for the green malt. The drying is implemented for a specified maximum kiln time. To do this, grain moisture content and a grain mass of a grain are detected, which constitutes a basis for the bed of drying material of the green malt after steeping and germinating, Furthermore, an ambient air humidity of an ambient air used for the air mass flow and a plurality of weather forecast data are detected at least with respect to the ambient air humidity and, during drying, a moisture content of the drying material of the green malt is monitored up to a specified limit. A rotational speed modulation of the fan is controlled such that the specified maximum kiln time is reached.

Claims

1-19. (canceled)

20. A process for energy-efficient drying of germinated seed in a drying kiln using a rotational speed-modulated fan for directing an air mass flow through a bed of drying material for the germinated seed, comprising: detecting a grain moisture content and a grain mass of a grain which is a basis for the bed of drying material of the germinated seed after steeping and germinating; detecting an ambient air humidity for ambient air used for the air mass flow; detecting weather forecast data, at least with respect to the ambient air humidity; monitoring, while drying, a drying material moisture content of the germinated seed up to a specified limit; and setting a rotational speed modulation of the fan such that a specified maximum kiln time is reached and/or maintained, based on the moisture content of the grain, the grain mass, the ambient air humidity, the weather forecast data, and a moisture content of the drying material of the germinated seed.

21. The process according to claim 20, wherein: the germinated seed comprises green malt.

22. The process according to claim 20, wherein: the detecting of the ambient air humidity detects an absolute ambient air humidity of the ambient air used for the air mass flow.

23. The process according to claim 22, wherein: the detecting of the weather forecast data detects the absolute ambient air humidity.

24. The process according to claim 23, wherein: the detecting of the weather forecast data continuously detects the absolute ambient air humidity for a time duration defined from loading of the kiln and/or from a start of the rotational speed-modulated fan.

25. The process according to claim 24, wherein: the time duration corresponds to a duration of a scheduled drying time.

26. The process according to claim 20, wherein: the limit of the moisture content of the drying material of the germinated seed is a maximum of 10%.

27. The process according to claim 26, wherein: the limit of the moisture content of the drying material of the germinated seed is a maximum of 5%, or between 5% and 7%, or between 5% and 10%.

28. The process according to claim 20, wherein: the detecting of the moisture content of the grain, the grain mass, the ambient air humidity, the weather forecast data with respect to the ambient air humidity and the moisture content of the drying material of green malt are intelligently performed such that the rotational speed modulation of the fan is done in such a way that the maximum kiln time is reached and/or is maintained, and an energy consumption forecast is ascertained.

29. The process according to claim 28, wherein: drying of germinated seeds in the kiln comprises at least withering and curing as two drying phases, wherein for the withering of the green malt in the kiln, the energy consumption forecast is ascertained.

30. The process according to claim 29, wherein: the drying of germinated seeds in the kiln comprises heating up between the withering and the curing, wherein for the heating up of the germinated seed in the kiln, the energy consumption forecast is ascertained.

31. The process for energy-efficient drying of germinated seeds according to claim 28, wherein: the energy consumption forecast is ascertained for curing of the germinated seed in the kiln.

32. A device for energy-efficient drying of germinated seed, comprising: a drying kiln; a rotational speed-modulated fan for directing an air mass flow through a bed of drying material for the germinated seed; a detector for detecting a grain moisture content and a grain mass of a grain which is a basis for the bed of drying material of the germinated seed after steeping and germinating; a detector for detecting an ambient air humidity for ambient air used for the air mass flow; a detector for detecting weather forecast data, at least with respect to the ambient air humidity; circuitry configured to monitor, while drying, a drying material moisture content of the germinated seed up to a specified limit; and circuitry configured to set, via a data transmission network, a rotational speed modulation of the fan such that a specified maximum kiln time is reached and/or maintained, based on the moisture content of the grain, the grain mass, the ambient air humidity, the weather forecast data, and a moisture content of the drying material of the germinated seed.

33. The device according to claim 32, wherein: the circuitry configured to set is connected by the data transmission network to a rotational speed actuator of the fan for dynamic rotational speed modulation of the fan.

34. The device according to claim 32, wherein: the detector for detecting the grain moisture content monitors up to a specified limit via an inline moisture detector.

35. The device according to claim 32, wherein: the detector for detecting the ambient air humidity performs the detecting during withering.

36. The device according to claim 32, further comprising: a memory for storing forecast information corresponding to absolute exhaust air humidity during withering, wherein the circuitry configured to set uses the forecast information corresponding to absolute exhaust air humidity during withering.

37. The device according to claim 32, further comprising: a memory for storing forecast information corresponding to exhaust air humidity during withering, wherein the circuitry configured to set uses the forecast information corresponding to exhaust air humidity during the withering.

38. The device according to claim 36, further comprising: a forecast module which is trained using machine learning to generate the forecast information.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention is explained in more detail by means of examples with reference to the drawings in which is shown:

[0023] FIG. 1 shows a diagram that illustrates, for example, how many drying kilns are typically operated in a certain rhythm (for example, 20 h, 24 h, 32 h, 36 h or 48 h etc.). In other words, every day at about the same time the entire quantity of green malt to be kilned is loaded onto a floor, whereas previously the pre-dried (withered), then completely dried (kilned) and finally cooled malt has been unloaded. The various phases in FIG. 1 comprise (i) loading 2-3 h, (ii) withering 8-12 h, (iii) heating-up 3-4.5 h, (iv) curing 3.5 h, (v) cooling 0.5-2 h, and finally (vi) unloading 2-3 h. In double-deck drying kilns it is to be mentioned that, in the case of a double-deck drying kiln operated at a 24-hour rhythm, every day at about the same time, the entire quantity of green malt to be kilned is loaded onto a floor, whereas the second, other floor is provided with the pre-dried (withered) malt from the previous day for completely drying (curing). In these cases, in this way, one batch is actually kilned in the 224=48 hour cycle. Of course, this has the prerequisite that each floor can take the same full quantity of green malt. It is to be mentioned once again that, for double-deck drying kilns, other possibilities than those mentioned above exist, for example, that the material remains on the floor on which it is and instead of reloading onto the second floor, the air flow is switched over and reverses from the first floor to the second floor. The present invention, however, can be applied, regardless of the selected kilning option, therefore relating to both single-deck kilning and also all possible double-deck kilning, particularly when it is operated at a certain rhythm.

[0024] FIG. 2 shows an example diagram that illustrates schematically another kilning scheme of a continuous single floor drying kiln of the prior art. In this case, the temperature below the floor is continuously increased, or in steps, for example, in time intervals, until the desired moisture content of 3 to 8% of the malt grains is achieved. Withering 2 h at 50 C. and 2 h at about 57 C. and curing for about 5.5 h at 62 C., about 2 h at 68 C., about 1.5 h at 72 C., about 2 h at 80 C. and about 4 h at 85 C., in other words, up to an exhaust air temperature of approximately 80 C. Heating up for about 4 h from 65 to 80 C., curing for about 5 h at 80-85 C. That produces a total duration of the kilning process, in other words, of withering and kilning of 19 h. As mentioned for kilning, the green malt is dried from a moisture content of 38 to 46% to a single-figure value of 3 to 8%. This happens in the two withering and curing sub-steps: during withering, the temperature of the exhaust air remains relatively constant (see FIG. 2), whereas the outflowing air of the drying kiln is saturated virtually 100% with moisture. In the second phase, curing, the temperature also rises considerably inside the grain and the water is further and further extracted through the capillary effect. The downstream side air of the drying kiln is no longer saturated 100% with moisture at this stage (see FIG. 2).

[0025] FIG. 3 shows an example diagram that illustrates schematically how the entire process duration of kilning changes with the selected rotational speed of the fan. In the case where the rotational speed n=100%, the kilning time is less than for a lower rotational speed n=90%. For example, the case is also listed here, in which a maximum kilning time specified on the part of the industrial malting system is then precisely achieved, if during withering, heating up and curing, the fan is only operated with a rotational speed of n=80%; in this case, the saving mentioned above of around 39% in electrical energy for the fan is achievable. In turn, it is to be noted that although a reduction of the fan rotational speed reduces the fan power consumption by 27% or even 49%, due to the extension of the withering time, the reduction of power does not lead through to a 1:1 energy consumption saving for the entire process. In the example listed (reduction of the fan power consumption by 49%), the reduced fan power consumption, considering the extended withering period, reduces the entire electrical energy requirement of the fans by 39%. In other words, it is typically simpler to specify the reduction of the fan power, as this can be calculated directly, wherein it is to be noted, however, that the energy requirement will drop less due to the relationship mentioned above (RPMV.sub.L; RPMt; RPMP.sup.3). Basically, however, the moisture content of below 10%, for example, 3-8% or below 5% of the malt grains is a decisive final target after kilning. FIG. 3 shows three cases, in other words, an initial situation (case 1 (initial)), a case 2 and a case 3. In the initial situation, the fan is operated at 100% rotational speed, the withering time for which is 10 hours (withering time=10 h) and the total kiln time is 17 hours (total kiln time 1 h), wherein in the energy consumption is 5 500 kWh.sub.el. In case 2, the fan is operated at 90% rotational speed, the withering time for which is 11 hours, the total kiln time is 18 hours, and the energy consumption is 4 455 kWh.sub.el. This corresponds to a reduction of energy consumption by 19% of the total electrical energy consumed by the fan, wherein the power consumption of the fan is lowered by 27%, but the withering time and the kiln time are extended by 1 h each. In case 3, the fan is operated at 80% rotational speed, the withering time for which is 12 hours and the total kiln time is 19 hours, wherein the energy consumption is 3 420 kWh.sub.el. This corresponds to a reduction of energy consumption by 38% of the total electrical energy consumed by the fan, wherein the power consumption of the fan is lowered by 49%, but the withering time and the kiln time are extended by 2 h each. Case 3 corresponds to the maximum possible extension of the kiln time within the process, without fixed provided times of the process steps, particularly the kiln time, being affected. In other words, the longer kiln times reduce the energy consumption at lower fan rotational speeds. The device and process according to the invention therefore allow the fan rotational speeds to be adjusted so that an optimal exploitation of the kilning phase available is achieved at the maximum possible time.

[0026] FIG. 4 shows a diagram which illustrates schematically that the withering and corresponding times are not constant, but, for example, are affected by: (i) weather conditions (for example, absolute humidity of the fresh air/supply air), (ii) initial moisture content of the malt, (iii) batch loading, and (iv) air mass flow: depending on the fan rotational speed, batch size, loading quality. Further influencing factors may comprise, for example, drying temperature, exhaust air humidity etc. It is to be pointed out that quantities that have not been able to be affected to date in the prior art, such as, for example, the trend of air humidity over time, for example, based on weather forecast measurement parameters, cannot be considered.

[0027] FIG. 5 shows a diagram that illustrates schematically that the resulting total kiln times are particularly dependent on (i) loading time (step 1), (ii) withering (step 3) maximum effect on variability, and (iii) final curing (step 10)

[0028] FIG. 6 shows a diagram that illustrates schematically the correlation of the fan rotational speed (n): (i) linearly with air mass flow: n{dot over (m)}A, and (ii) to the power of three with the power consumption: n(P.sub.F).sup.3. A reduction of fan rotational speed by 10% extends the drying by 10%, a reduction of the fan rotational speed by 10% reduces the fan power by 27%, whereas, for example, a reduction of the fan rotational speed by 20% extends drying by 20% and reducing the fan rotational speed by 20% reduces the fan power by 49%.

[0029] FIG. 7 illustrates schematically an architecture of a possible realization of an embodiment variant for energy-efficient drying of green malt 2 in a drying kiln 1 using a rotational speed-modulated fan 3 for directing an air mass flow 4 through a bed of drying material 2.1 of the green malt 2. In this case, drying is implemented for a specified maximum kiln time (t.sub.max).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT VARIANTS

[0030] FIG. 7 illustrates schematically an architecture of a possible realization of an embodiment variant for energy-efficient drying of green malt 2 in a drying kiln 1 using one or more rotational speed-modulated fans 3 for directing an air mass flow 4 through a bed of drying material 2.1 of the green malt 2. In this case, drying is implemented for a specified maximum kiln time (t.sub.max).

[0031] A grain moisture content (Hg) and a grain mass (Mg) of a grain 2.2 are recorded. The grain 2.2 constitutes, after steeping 5 and germinating 6, a basis for the bed of drying material 2.1 of the green malt 2. By means of measuring sensors, an ambient air humidity (Hl) of an ambient air 7 used for the air mass flow 4 is detected. In, addition, for example, an absolute ambient air humidity (Hla) of an ambient air 7 used for the air mass flow 4 may be detected.

[0032] The weather measurement data are detected by means of measuring stations. Based on the weather measurement data, a plurality of weather forecasts (W1, W2), at least with respect to the ambient air humidity (Hl) is detected or generated. The plurality of weather forecast data (W1, W2) may, for example, be generated or detected, for example, at least with respect to the absolute ambient humidity (Hla). The plurality of weather forecast data (W1, W2) may, for example, be generated or ascertained continuously, in other words, dynamically, with respect to the absolute ambient air humidity (Hla) for the 12 hours following on from loading 8 the drying kiln 1 and/or from the start of the fan of the drying kiln. The term from loading the drying kiln may include or have the prerequisite in this patent, that the loading has been completed. The reason for this is that for certain embodiment variants already before the end of loading, for example, from half the loading time, the fan has already started and drying has already begun, so as not to lose any time. While drying, a moisture content of the drying material (Ht) of the green malt 2 is monitored up to a specified limit (Gt). The limit (Gt) of the moisture content of the drying material (Ht) of the green malt may, for example, be maximum 3-8%, for example 5%. Other values are also possible. For example, the target water content may also be defined after the withering phase, for example, in a range of 12-20%.

[0033] Based on the moisture content of the grain (Hg), the grain mass (Mg), the ambient air humidity (Hl), the plurality of weather forecasts (W1, W2), with respect to the ambient air humidity (Hl) and based on the moisture content of the drying material (Ht) of the green malt 2, a rotational speed modulation of the fan 3 is undertaken in such a way that the specified maximum kiln time (t.sub.max) is reached and/or maintained. Detecting the moisture content of the grain (Hg), the grain mass (Mg), the ambient air humidity (Hl), the plurality of weather forecast data (W1, W2) with respect to the ambient air humidity (Hl) and the moisture content of the drying material (Ht) of the green malt (2) may, for example, be done by means of an intelligent system unit 15 of the kiln, with which the rotational speed modulation of the fan 3 is done in such a way that the maximum kiln time (t.sub.max) is reached and/or is maintained, and an energy consumption forecast (Ev) is ascertained.

[0034] For drying the green malt 2, for example, the fan 3 may be connected to the intelligent system unit 15 bidirectionally via a data transmission network 16 to generate the air mass flow 4 through the bed of drying material 2.1 of the green malt 2, wherein the intelligent system unit 15 [may] be connected to a grain moisture content sensor 17 and/or grain mass sensor 18 and/or an ambient air humidity sensor 19 and/or a plurality of sensors for weather measurement data and a forecast unit for generating the weather forecast data 20.1, 20.2 and/or a sensor for the moisture content of the drying material 21 of the green malt 2, wherein the intelligent system unit 15 furthermore comprises an optimization means 15.1 for dynamic optimization and/or adaptation and/or learning of working steps 8-14 for energy-efficient drying of green malt 2. For the dynamic rotational speed modulation of the fan 3, for example, the optimization means 15.1 of the intelligent system unit 15 may be 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. As an embodiment variant, valve adjustments, for example, of the supply air, exhaust air or with the pressure fans can be considered by the intelligent system unit 15, or even used as input or output parameters. As described, the ventilation of the kiln is done via a correspondingly dimensioned fan. It draws in the air either from a fresh air shaft or from a return air channel and pushes this into the pressure chamber located above. From there, the air penetrates the material lying on the floor and is carried away into the exhaust air channel. This forms a common shaft with the return air channel. The directional guidance of the air may, for example, be done by a closing return air valve or a gate valve. The air advance by a fan ensures, at the same level as the material, particularly as uniform as possible ventilation. Furthermore, the regulation of the quantity of air may also be realized by exhaust air gate valves and/or by valves in the channels before the fan. Nevertheless, the most direct regulation option is done via (or additionally via) the fan rotational speed, for example, using frequency-regulated motors, wherein these are controlled automatically by the intelligent system unit 15, for example, depending on the temperature difference between the upper malt layer and the inflowing air. FIG. 2 shows an example scheme of such a process. Withering 2 h at 50 C. and 2 h at about 57 C. and curing for about 5.5 h at 62 C.; about 2 h at 68 C.; about 1.5 h at 72 C., about 2 h at 80 C. and about 4 h at 85 C., in other words, up to an exhaust air temperature of approximately 80 C. Heating up in 4 h from 65 to 80 C., curing for 5 h at 80-85 C. That produces a total duration of withering and kilning of 19 h. At an exhaust air temperature of 40 C., for example, an additional rotational speed regulation may be used. The difference from the temperature in the interior may still be, for example, about 30 C. at this time. At an exhaust air temperature of 30 C., therefore, already before the start of curing, for example, a circulating air valve may be opened. The return air proportion is then, for example, 50-70% at the end of the kiln time. As mentioned for kilning, the green malt is dried from a moisture content of 38 to 46% to a single-figure value of 3 to 8%. This happens in the two withering and curing sub-steps: During withering, the temperature of the exhaust air remains relatively constant (see FIG. 2), whereas the outflowing air of the drying kiln is saturated virtually 100% with moisture. In the second phase, curing, the temperature also rises considerably inside the grain and the water is further and further extracted through the capillary effect. The downstream side air of the drying kiln is no longer saturated 100% with moisture at this stage (see FIG. 2).

[0035] As an embodiment variant, for example, the absolute exhaust air humidity during withering may be ascertained. The device may, for example, comprise a forecasting module, by means of which, based on measured weather data, such as, for example, ambient temperature, air pressure, air humidity of the environment etc., this exhaust air humidity and the exhaust air humidity at the start of kilning is determined in a forward-looking process. The forecast module may be realized as a machine-learning unit which in a supervised learning phase, by means of a feedback loop, an appropriate measurement parameter is learned for transferring. Alternatively, only ever by means of classifying by an unsupervised learning structure may the associated measurement parameter pattern be detected with a certain measured exhaust air humidity. This may be used directly for forecast determining of the exhaust air humidity or as an input for the supervised learning structure.

[0036] As an embodiment variant, for example, for the working step of withering 9 the green malt 2, an energy consumption forecast (Ev) of the kiln 1 may be generated. Also, for example, for a working step of heating up 11 the green malt 2 in the kiln 1, the energy consumption forecast (Ev) may be generated. Furthermore, for example, for the working step of curing 12 the green malt 2, and energy consumption forecast (Ev) of the kiln may also be ascertained or generated. As a further embodiment variant, for example, a specific self-test can be implemented as a safety test by means of the device. The safety check may comprise the following implementation steps: (i) Checking whether the ambient conditions are positive and the implemented safety check structure may be applied; (ii) Review/scan of sensors: detecting defined conditions, such as, for example, in one of the two fans, one of the two burners, the temperature and moisture sensor via KLN during step 0-1-2 is faulty for more than 10 min; (iii) Review of the absolute fresh air humidity after a defined limit trigger value: For example, if for one variant no more than 10 g/kg is to be for stage 2 etc.; (iv) Review of the duration of step 1: For example, it must not be more than 2.5 hours; (v) Review of the duration of step 2: For example, it must not be more than 3 hours; (vi) Checking the absolute delta moisture through the furnace-AH fresh air: for example, it should be more than 10 g/kg; (vii) Green malt content: for example, checking whether the content is <45%; (viii) Interruption of the process if one of the trigger criteria are not met. Also as an embodiment variant, risk buffers may be provided: (i) Based on the calculation of an m.c. after withering of 12%.fwdarw.probably 15 to 18% (3-5% buffer); (ii) The fan rotational speed may be limited, for example, to 75%, to avoid a risk and come out of the ideal range.fwdarw.If the generated forecasts are respectively true, the limit can be reduced; (iii) Stage 4 still runs at 100% fan rotational speed.fwdarw.if under-drying actually occurs during withering, a compensation in stage 4 is very probable due to the high fan rotational speed+increasing temperatures: Time buffer=90 minutes (i.e. 180 min.fwdarw.270 max); (iv) Maximum permitted withering time is, for example, 9 h.fwdarw.Then, for example, a risk buffer as maximum kiln time=21.5 h including loading time+2 h for cooling can be regulated;(v) Calculations may, for example, be based on 8.5 h, to increase the fan speed.fwdarw.additional buffer; (vi) The process may start with malt batches (or other less sensitive batches), that are produced for foodstuff applications, in which the specifications are less critical than for brewing applications. The aim of the risk buffer is to keep the risk of under-drying automatically as low as possible in the process.

LIST OF REFERENCE NUMERALS

[0037] 1 Kiln [0038] 2 Germinated Seeds, e.g. Green Malt [0039] 21 Bed Of Drying Material [0040] 22 Grain [0041] 3 Fan [0042] 31 Rotational Speed Actuator Of 3 [0043] 4 Air Mass Flow [0044] 5 Steeping [0045] 6 Germinating [0046] 7 Ambient Air [0047] 8 Loading [0048] 9 Withering [0049] 10 Breakthrough [0050] 11 Heating Up [0051] 12 Curing [0052] 13 Cooling [0053] 14 Unloading [0054] 15 Intelligent System Unit [0055] 15.1 Optimization Means [0056] 16 Data Transmission Network [0057] 17 Grain Moisture Content Sensor [0058] 18 Grain Mass Sensor [0059] 19 Ambient Air Humidity Sensor [0060] 20 Sensors for Weather Measurement Data (20.1, 20.2) [0061] 21 Drying Material Moisture Content Sensor [0062] 22 Grain Store [0063] 23 Steep [0064] 24 Malting Box [0065] 25 Malt Silo [0066] 26 Weather Station [0067] 27 Kilned Malt [0068] n Rotational Speed Of 3 In % [0069] Ht Moisture Content Of Drying Material [0070] Gt Limit Of Ht [0071] Hg Grain Moisture Content [0072] Mg Grain Mass [0073] Hl, Hla Ambient Air Humidity, Absolute Ambient Air Humidity [0074] W1, W2 Weather Forecast Data From Hl (May Also Comprise Hla) [0075] Ev Energy Consumption Forecast [0076] t Kiln Time [0077] t.sub.max Specified Maximum Kiln Time