JP2022029378A - Fermentation and drying apparatus and fermentation and drying method - Google Patents

Abstract

To provide a fermentation and drying apparatus and a fermentation and drying method which can perform air-inlet control according to each of a fermentation stage and a drying stage, and can efficiently perform fermentation and drying.SOLUTION: A fermentation and drying apparatus 1 includes a rotary shaft 3 and agitating blades 4 provided in a container 2, an air feed blower 6, and exhaust means 9, and ferments and dries a fermentation raw material while introducing outside air into the container 2 and exhausting inside air from the container 2 by the exhaust means 9, and agitating the fermentation raw material with the agitating blades 4 includes: calculation means for calculating a change amount of a fermentation heat quantity at an arbitrary time interval; determination means for determining timing of changing the change amount from an increasing trend to a decreasing trend on the basis of the calculated change amount of the fermentation heat quantity; and operation control means for performing an operation mode of setting at least any one of an amount of the outside air introduced into the container and a temperature of the outside air introduced into the container to be larger than an item before the timing is determined, after the timing has been determined by the determination means.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fermentation drying apparatus and a fermentation drying method.

Conventionally, as a device for fermenting and drying fermented raw materials such as livestock excrement, food waste, and sewage sludge to compost, a closed vertical composting device using the fermentation action of microorganisms is known. This device has a cylindrical vertical tank shape, and ferments and dries while stirring and forcibly aerating the fermentation raw materials put into the closed container.

For example, Patent Document 1 discloses a closed-type fermentation / drying apparatus including a rotating shaft provided in a container, a plurality of stirring blades attached to the rotating shaft, an air supply means, and an exhaust means. There is. In this apparatus, the amount of heat of fermentation and the amount of water vaporized per predetermined time are used as fermentation indexes, and the amount of outside air introduced into the container is controlled based on the fermentation indexes. The amount of heat of fermentation and the amount of water evaporated as indicators are calculated based on the temperature and flow rate of the outside air introduced into the container and the temperature and flow rate of the inside air discharged from the container.

Japanese Unexamined Patent Publication No. 2018-172272

Generally, in the operation of the fermentation drying device, it is important to control the flow rate and temperature of the outside air introduced into the container. The functions of the outside air introduced into the container include (1) supplying oxygen for activating microorganisms, and (2) taking out water from the fermentation raw material and the container and drying it. Conventionally, in the fermentation / drying apparatus, although fermentation and drying are progressing in parallel, in the fermentation / drying process from the input to the removal of the fermentation raw material, the operation focusing on each of fermentation and drying has not been performed. On the other hand, it is empirically known that the degree of fermentation is large from the input of the fermentation raw material to a certain stage, and the degree of drying is large after that. Therefore, it is desirable to control the air intake with more emphasis on either fermentation or drying.

The present invention has been made in view of such circumstances, and in the fermentation and drying process from the input to the removal of the fermentation raw material, it is possible to control the air intake according to each of the fermentation stage and the drying stage, and the fermentation and drying can be performed. It is an object of the present invention to provide a fermentation / drying apparatus and a fermentation / drying method capable of efficiently carrying out the above. Specifically, the air intake control focusing on fermentation aims to further increase the amount of dry matter decomposition, and the air intake control focusing on drying aims to further increase the amount of water evaporation.

The fermentation / drying apparatus of the present invention comprises a rotating shaft provided in a container, a plurality of stirring blades attached to the rotating shaft, an air supply means for taking in outside air into the container, and inside air accumulated in the container. A closed-type fermentation / drying device provided with an exhaust means for discharging to the outside of the container, wherein the fermentation / drying device introduces outside air into the container by the air supply means and uses the exhaust means. It is a device for fermenting and drying the fermentation raw material while stirring with the stirring blade while exhausting the inside air from the container, and the fermentation drying device is the amount of change in the amount of heat of fermentation at an arbitrary time interval (hereinafter, also simply referred to as ΔQ). The timing is determined by the calculation means for calculating (referred to as), the determination means for determining the timing at which the change amount changes from the increasing tendency to the decreasing tendency based on the calculated change amount of the fermentation calorific value, and the determination means. After that, an operation mode in which at least one of the items of the amount of outside air introduced into the container and the temperature of the outside air introduced into the container is made larger than the item before the timing is determined is set. It is characterized by having an operation control means for performing.

In the present specification, the temperature of the outside air introduced into the container means the temperature of the outside air finally introduced into the container via the air supply means, the heater, etc., and this temperature is referred to as the "intake temperature". That is. When there are a plurality of inlet air passages, the average temperature of the outside air introduced into the container from each inlet air passage is taken as the intake air temperature. Further, in the present specification, the amount of outside air introduced into the container is the amount of outside air introduced into the container per unit time, and this is referred to as "intake amount". When there are a plurality of intake routes, the total amount of outside air introduced from each intake route per unit time is taken as the intake amount.

The operation control means is characterized in that, in the operation mode, at least one of the stirring frequency and the stirring speed of the stirring blade is made larger than the item before the timing is determined.

The determination means calculates the slope of the amount of change in the amount of heat of fermentation, the slope is less than the threshold value, the amount of heat of fermentation is increasing at that time, and the temperature of the inside air (exhaust temperature) is determined. It is characterized in that the timing is determined on condition that at least one of the increase and the temperature of the inside air being equal to or higher than a predetermined temperature is satisfied.

The operation control means has the amount of outside air introduced into the container, the temperature thereof, and the stirring in a predetermined period after the timing is determined by the determination means and before the operation mode is performed. It is characterized in that at least one of the stirring frequency of the blade and the stirring speed thereof is made smaller than the item before the timing is determined.

The predetermined period is characterized in that it is a period from the time when the timing is determined by the determination means until the amount of change in the amount of heat of fermentation becomes negative.

In the fermentation drying method of the present invention, a rotating shaft provided in a container, a plurality of stirring blades attached to the rotating shaft, an air supply means for taking in outside air into the container, and inside air accumulated in the container are used. It is a fermenting and drying method in a closed type fermenting and drying device provided with an exhaust means for discharging to the outside of the container. It is a device for fermenting and drying the fermentation raw material while stirring the fermentation raw material with the stirring blade while exhausting the inside air from the container by the exhaust means, and the fermentation drying method calculates the amount of change in the amount of heat of fermentation at an arbitrary time interval. After the calculation step is performed, the determination step of determining the timing at which the change amount changes from the increasing tendency to the decreasing tendency based on the calculated change amount of the fermentation heat amount, and after the timing is determined by the determination step. It has an operation control step in which at least one of the items of the amount of outside air introduced into the container and the temperature of the outside air introduced into the container is made larger than the item before the timing is determined. It is characterized by.

The fermentation / drying apparatus of the present invention has a calculation means for calculating the amount of change in the amount of heat of fermentation at an arbitrary time interval, and a timing at which the amount of change changes from an increasing tendency to a decreasing tendency based on the calculated amount of change in the amount of heat of fermentation. At least one of the items of the in-air amount and the in-air temperature to be introduced into the container after the above-mentioned timing is determined by the determination means and the determination means is set from the items before the above-mentioned timing is determined. Since it has an operation control means for performing an operation mode in which the temperature is increased, after the timing is determined, it is possible to perform air intake control with particular emphasis on drying in order to increase the amount of water evaporation. As a result, in the fermentation and drying process from the input to the removal of the fermentation raw material, the air intake can be controlled according to each of the fermentation stage and the drying stage, and the fermentation and drying can be efficiently performed.

It is a vertical sectional view which shows an example of the fermentation drying apparatus of this invention. It is a schematic diagram of the intake / exhaust path of the fermentation drying apparatus of a test example. It is a figure which shows the time transition of a fermentation calorie Q and an exhaust temperature. It is a figure which shows the correlation of the change amount ΔQ of the fermentation heat quantity, and the exhaust temperature. It is a figure which shows the time transition of a fermentation calorie Q and an exhaust temperature. It is a figure which shows the correlation of the change amount ΔQ of the fermentation heat quantity, and the exhaust temperature. It is a figure which shows an example of the operation mode divided according to the change amount ΔQ of the fermentation heat quantity. It is a figure which shows the other example of the operation mode divided according to the change amount ΔQ of the fermentation heat quantity. It is a model diagram which shows the time transition of the exhaust temperature in the operation control of FIG. It is a figure which shows the result for each calculation span of the change amount ΔQ of the amount of heat of fermentation.

The outline of the fermentation drying apparatus of the present invention will be described with reference to FIG. FIG. 1 is a vertical cross-sectional view showing an example of the configuration of a fermentation drying device. As shown in FIG. 1, the fermentation / drying device 1 includes a cylindrical vertical container 2, a rotary shaft 3 provided in the container 2 in the vertical direction, and a plurality of stirring machines provided around the rotary shaft 3 in multiple stages. A closed vertical type provided with a wing 4, an air supply blower 6 as an air supply means for taking in outside air into the container 2, and an exhaust means 9 for discharging the inside air accumulated in the container 2 to the outside of the container. It is a fermentation and drying device (component) of. The device in the present invention is mainly intended for a large-scale device for business use in which the internal volume of the container 2 is 10 m ³ or more. The shape of the stirring blade 4 is not particularly limited, and may be, for example, a pitched paddle shape extending linearly from the rotation shaft 3 toward the inner wall side of the container 2, and having an inclined surface on the front side in the rotation direction thereof.

A ventilation hole 4a is provided in the lower part of the lowermost stirring blade, and the outside air (inlet air) sent from the air supply blower 6 is introduced into the container through the ventilation hole through the pipe 6a provided in the rotating shaft. There is. The container 2 which is a fermenter is a heat insulating container having a metal outer layer and a heat insulating layer, and is an airtight container which is hard to come into contact with outside air other than introduced from the ventilation holes. Further, the upper part of the container 2 has an input port 2a for fermented raw materials and an exhaust port 2c, and the bottom part has an outlet 2b for the fermented dried product after treatment. The exhaust port 2c is connected to the exhaust means 9. The inlet 2a and the outlet 2b are provided with a lid that can be opened and closed to ensure the airtightness of the container.

In the form shown in FIG. 1, a machine room 5 is provided below the container 2, and a hydraulic cylinder 8 as a driving means for the rotating shaft 3 and the above-mentioned air supply blower 6 are provided in the machine room. The rotary shaft 3 penetrates into the machine room 5 and is rotated at a predetermined rotation speed by the hydraulic cylinder 8. As the air supply blower 6, it is preferable to use one whose blower rotation speed can be controlled by the inverter frequency in order to make it possible to adjust the amount of air input. Further, an air supply valve for adjusting the amount of incoming air may be provided in the middle of the pipe 6a.

Gas, water vapor, and the like generated in the container are exhausted from the exhaust port 2c to the outside air via the exhaust means 9. The exhaust means 9 includes an exhaust pipe 10, an exhaust blower 11, and a deodorizing device 12. The exhaust blower 11 forcibly exhausts gas or the like in the container. The deodorizing device 12 is, for example, a water-washing scrubber that captures odorous components by bringing water as a cleaning liquid into contact with gas or the like. Examples of the odorous component include lower fatty acids such as propionic acid, normal butyric acid, and isovaleric acid, sulfur compounds, and ammonia. The exhaust pipe 10 between the container 2 and the exhaust blower 11 is provided with a temperature sensor 13 for detecting the exhaust temperature.

In the form shown in FIG. 1, a heater 7 for heating the outside air sent from the air supply blower 6 is provided. The heater 7 is not essential, and for example, a heat exchange means (not shown) may be provided to heat the outside air introduced into the container from the air supply blower 6 by using the heat of the exhaust gas from the exhaust means 9. In this case, the heater can be eliminated and the running cost can be reduced. The form and installation location of the heat exchange means are not particularly limited, and examples thereof include passing an air supply pipe before introduction into the container into a heat exchange device filled with exhaust gas.

The fermentation / drying device 1 may have an external heat insulating panel installed so as to cover at least a part of the outer periphery of the container 2 through a space. By providing an external heat insulating panel and forming a double heat insulating structure with the container, more stable processing becomes possible in the device installed outdoors. Examples of the shape of the external heat insulating panel include a square cylinder in which the outer wall of the device composed of the panel substantially circumscribes the outer periphery of the cylinder of the container.

In the fermentation and drying apparatus of the present invention, the fermentation raw material to be subjected to the fermentation and drying treatment includes livestock excrement, food waste, sludge, or a mixture thereof, which contain a large amount of organic components. Specifically, livestock excrement includes chicken manure, pig manure, cow manure, horse manure, etc., food waste includes food waste, food manufacturing by-products, etc., and sludge includes sludge generated from sewage treatment facilities, agriculture, etc. Examples include sludge generated from village wastewater treatment facilities, sludge generated in the livestock sewage treatment process, and sludge generated in the wastewater treatment process of food factories. Further, the fermentation drying process in the fermentation drying device is performed by aerobic fermentation in a container in the presence of aerobic fermenting bacteria while aerating. The aerobic fermenting bacterium is preferably a fermenting bacterium that is activated at about 30 to 90 ° C., and examples thereof include the genus Diovatisul and the genus Bacillus.

In the fermentation / drying apparatus 1 of FIG. 1, the fermentation raw material is put into the inside of the container 2 from the charging port 2a, and after fermentation and drying in the container, the fermented and dried product is taken out from the outlet 2b at the bottom of the container. For fermentation and drying, the air supply blower 6 introduces the outside air from the ventilation hole 4a of the lowermost stirring blade with a predetermined amount of air, and the inside air is exhausted from the exhaust port 2c and the exhaust means 9, and each stirring is performed. The wing 4 is rotated at a low speed to agitate and agitate sewage sludge, which is a fermentation raw material, for aerobic fermentation. It is also dried at the same time by ventilation. The air exhausted from the exhaust port 2c contains gas and water vapor generated from the fermentation raw material in the air introduced into the container through the ventilation holes and flowing upward while passing through the processed material. It should be noted that the inflow to the inside of the container is not limited to the ventilation hole 4a of the lowermost stirring blade, but the ventilation hole is provided in the uppermost stirring blade of the lowermost stage so that the air can be introduced from the ventilation hole. May be good. In that case, air may be supplied from a separately provided air supply blower to the ventilation hole of the stirring blade at the uppermost stage, which is one at the lowermost stage.

As an operation procedure, first, the fermentation raw material is charged into the fermentation / drying apparatus, leaving a space (head space) of 10 to 30% with respect to the internal volume of the apparatus. By adding the fermentation raw material leaving a space of 10 to 30%, stirring is sufficiently performed, so that fermentation and drying are efficiently performed. It is added every day, fermented and dried for a predetermined residence period (about 3 to 20 days), and a predetermined amount (for example, about 20% by mass) of fermented and dried product is taken out at regular intervals (for example, every day). The above feeding is performed after the fermented dried product is taken out. In this way, a part of the fermentation raw material is added and a part of the fermented dried product is taken out repeatedly in a fixed time cycle to continuously perform the treatment. The obtained fermented dried product is usually in the form of smooth powder.

As shown in FIG. 1, the fermentation drying device 1 is provided with a control panel 14 that controls the operation of the device. With the control panel 14, for example, switching between the automatic operation mode and the manual operation mode, various setting operations of the automatic operation mode, and various operations in the manual operation mode (for example, ON / OFF of the air supply blower 6 and ON / OFF of the exhaust blower 11 / It can be turned off, the hydraulic cylinder 8 can be turned on and off, the bucket (not shown) can be raised and lowered, and the like).

As described above, in a series of fermentation and drying treatments from the input to the removal of the fermentation raw material, the fermentation and drying of the fermentation raw material are basically performed at the same time. As a result of investigating the relationship between the amount of change in the amount of heat of fermentation ΔQ and the exhaust temperature, the present inventors have found that the amount of change in the amount of heat of fermentation ΔQ increases over a certain temperature range even though the exhaust temperature is increasing. We found that it started to decrease. Furthermore, it has been found that by using this change amount ΔQ as an index, it is possible to control the air intake specialized for each of the fermentation stage and the drying stage. The present invention is based on such findings.

In the fermentation drying apparatus 1 of the present invention, the change amount ΔQ changes from an increasing tendency to a decreasing tendency based on the calculation means for calculating the change amount ΔQ of the fermentation heat amount at an arbitrary time interval and the calculated change amount ΔQ. It is characterized by having a determination means for determining the timing and an operation control means for performing a predetermined operation mode after the timing is determined by the determination means. The control device 15 of FIG. 1 includes these calculation means, determination means, and operation control means, and is mainly composed of a microcomputer including a well-known CPU, ROM, RAM, and the like. The control device 15 is configured to continuously acquire and store information from a temperature sensor capable of measuring the temperature of air at each point, an acquisition means capable of acquiring an inflow amount, an acquisition means capable of acquiring an exhaust amount, and the like. ing. The control device 15 also has various arithmetic functions.

The above calculation means repeatedly acquires the amount of heat of fermentation at arbitrary time intervals. Then, each time it is acquired, the difference (change amount ΔQ) between the amount of heat of fermentation at the current time point and the amount of heat of fermentation at the time point before a predetermined time is calculated. In the present invention, the time interval between the current time point and the time point before a predetermined time in the calculation of ΔQ is referred to as a calculation span. The calculation span can be set as appropriate, for example, from a short interval of about 1 minute to several minutes to a relatively long interval such as 60 minutes or 120 minutes. The calculated span may be the same as or different from the time interval for acquiring the amount of heat of fermentation.

Below, first, the relationship between the amount of change in the amount of heat of fermentation ΔQ and the exhaust temperature will be described using a test example carried out at a pig farm. In this test, a component S-36ET (volume 39 m ³ ) manufactured by Chubu Ecotech Co., Ltd. was used as a fermentation drying device. A schematic diagram of the intake / exhaust path of this fermentation drying device is shown in FIG.

As shown in FIG. 2, the fermentation / drying device 1'is configured to continuously supply air with the air supply blowers 6A and 6B and exhaust the air from the exhaust port 2c at the top of the container with the exhaust blower 11. The air supply to the lowermost stirring blade 4A is performed by the air supply blower 6A installed at the lower part of the container, and the air supply from the lowest stage to the second stage stirring blade 4B is performed by the air supply installed at the upper part of the container. It is performed by the blower 6B. Filters 16A and 16B are provided on the upstream side of the air supply blowers 6A and 6B, respectively. This test was carried out in an intermittent operation in which the stirring blade of the fermentation drying device 1'rotated for 7 minutes and stopped for 9 minutes as one cycle. In addition, the inflow amounts of the air supply blowers 6A and 6B installed in the lower part and the upper part were combined at 0.20 m ³ / min · m ³ per fermentation tank volume. During the test period, the heater 7 for heating the outside air was not operated and was operated under the condition of no heating, but the outside air passing through the air supply blowers 6A and 6B was heated by each air supply blower.

The fermented dried product was taken out once a day from the outlet at the bottom of the container, and about 1400 kg was taken out on average. After the fermented dried product was taken out, about 3300 kg of pork feces, which was the raw material for fermentation, was added once a day by a bucket from the inlet at the top of the container without adjusting the water content and specific gravity. The removal of the fermented dried product and the input of the fermented raw material were basically carried out every day at a predetermined time (between 9:00 am and 11:00 am).

The test was conducted for 11 days from February 5th to February 15th, and the amount of heat of fermentation Q, the amount of change in the amount of heat of fermentation ΔQ, the temperature at each point of the intake route, the exhaust temperature, the amount of intake, the amount of exhaust, the humidity of the outside air, The temperature inside the container, the weight of the container, etc. were acquired at any time. The amount of heat of fermentation Q and the amount of change ΔQ thereof were calculated using the following formulas (1) to (4).

The temperature at each point of the intake path is measured at two points a to d shown in FIG. 2 (point a: outside air (lower part), point b: after blower (lower part)), and the exhaust temperature is at point e. It was measured. At these points, the temperature inside the pipe was measured at 1-minute intervals with a K thermocouple (manufactured by Shimaden, model number: STD-23S series). The amount of air introduced into the container (unit: m ³ / h) is measured by measuring the wind speed in the pipes at points b and d with an anemometer (manufactured by Kanomax Japan, model number: 0965-00), and is as follows. The total amount of each value obtained by the formula (1) was used. The displacement was 1.2 times the amount of intake air.

The numerical value of 0.82 in the above equation (1) indicates an average velocity coefficient represented by 2n ² / (n + 1) × (2n + 1), and when the number of blades of the stirring blade is n = 7. It is a numerical value of.

The amount of heat in the air of the fermentation drying device was the sum of the amount of heat Qg (b) after the blower (lower part) and the amount of heat Qg (d) after the blower (upper part), and each amount of heat was calculated by the following formula (2). For the post-blower (lower) calorific value Qg (b) and the post-blower (upper) calorific value Qg (d), the relative humidity of the outside air (lower) calorific value Qg (a) and the outside air (upper) calorific value Qg (c) per unit volume. The amount of water vapor was calculated, and the amount of heat was calculated on the assumption that the amount of water did not change even if the temperature changed. The calorific value was calculated assuming that the temperature at point d was the temperature at point c + 24 ° C. The exhaust heat amount Qg (e) was also calculated by the following formula (2). Since the water vapor at point e was discharged in a nearly saturated state, the relative humidity of the exhaust was set to 100%. For the humidity of the outside air, the average value for each hour was calculated from the data for every 10 minutes observed by the local meteorological observatory, and used for calculating the calorific value.

Using each of the obtained calories, the fermentation calorific value Q (unit: MJ / h) per unit time was obtained from the following formula (3). In the formula (3), the amount of heat of the intake air is defined as the amount of heat supplied to the container, and the amount of heat of the exhaust gas is defined as the amount of heat of the sum of the amount of heat of the intake air and the amount of heat generated in the container. Assuming that there is no heat dissipation or heat storage in the device (container), the amount of heat of intake minus the amount of heat of intake is defined as the amount of heat of fermentation. That is, it can be said that the amount of heat for fermentation is the amount of heat generated by the fermentation and drying of the fermentation raw material in the apparatus (inside the container).

Using the obtained heat of fermentation Q per unit time, the amount of change ΔQ (unit: MJ / h) per hour was calculated from the following formula (4). The amount of change ΔQ in the formula (4) represents the amount of increase or decrease in the amount of heat of fermentation Q, and t represents the time.

FIG. 3 shows the data on February 10 of the above test period (February 5 to February 15). FIG. 3A shows the time transition of the amount of heat of fermentation Q and the exhaust temperature per unit time. The exhaust temperature represents an average value for one hour. In FIG. 3A, the amount of heat Q for fermentation increases from 14:00 to the right, peaks at 2 o'clock the next day, and then decreases until 9 o'clock the next day. Further, during the period of increase in the amount of heat of fermentation Q, the amount of heat of fermentation Q increased quadratically until 20:00, and then gradually increased. From the value of the second derivative of the approximate expression of the amount of heat of fermentation Q, the timing at which the amount of change ΔQ changed from the increasing tendency to the decreasing tendency was 20:00. In the time zone in which the increase in the amount of heat of fermentation Q became gradual, the slope (increase amount) of the exhaust temperature also became small.

FIG. 3B shows the change amount ΔQ of the amount of heat of fermentation and the time transition of the exhaust temperature. This amount of change ΔQ is the difference between the current amount of heat of fermentation Q (time shown in the graph) and the amount of heat of fermentation one hour ago. As shown in FIG. 3 (b), ΔQ peaked in the time zone from 19:00 to 20:00 and decreased thereafter. The amount of change ΔQ after the peak showed a movement from positive to negative after a sharp drop. In addition, when the change amount ΔQ becomes negative, it means that the fermentation heat amount Q decreases.

FIG. 4 shows a graph in which the change amount ΔQ of the amount of heat of fermentation is on the vertical axis and the exhaust temperature is on the horizontal axis. The circles in the figure are plots of the exhaust temperature during the period corresponding to each change amount ΔQ in FIG. 3 (b), and the dotted line in the figure is an approximate curve thereof. This curve represents the movement in the process of increasing the exhaust temperature and is irreversible. As shown in FIG. 4, the amount of change ΔQ changes from an increase to a decrease when the exhaust temperature is around 59 ° C to 60 ° C. In the present specification, the peak of the amount of change ΔQ is also referred to as an inflection point. Since the change amount ΔQ represents the amount of increase or decrease in the amount of heat generated when the microorganism decomposes the organic matter, it is the decomposition rate (growth rate) of the organic matter of the microorganism that the change amount ΔQ reaches a peak and reaches a plateau. Can be said to reach a plateau. That is, it is considered that the microorganisms are gradually inactivated during the period after the peak of the amount of change ΔQ. Further, in FIG. 4, the change amount ΔQ of the exhaust temperature is reversed at about 16 MJ / h.

Next, FIGS. 5 and 6 show data on another day (February 13). 5 and 6 are graphs corresponding to FIGS. 3 and 4, respectively. As shown in FIG. 5B, the amount of change ΔQ on February 13 is the maximum in the time zone from 20:00 to 21:00, and the exhaust temperature at the peak is about 59 ° C to 60 ° C. Further, as shown in FIG. 6, the approximate curve of the amount of change ΔQ shows the circumferentiality as in FIG. 4, and the inflection point where the increase changes to the decrease can be confirmed. As described above, even on another day, the fermentation heat amount Q, the change amount ΔQ, and the exhaust temperature are moving in the same manner as on February 10.

From the data of FIGS. 3 to 6 above, it was found that the amount of change ΔQ in the amount of heat of fermentation changed from increasing to decreasing at a certain temperature range of the exhaust temperature. It can be said that the peak of the amount of change ΔQ is the peak of the decomposition rate of organic matter of the microorganism, and it is considered that the activity and the growth rate of the microorganism decrease after the peak. Therefore, it can be said that the period before the peak of the change amount ΔQ is the stage in which fermentation is dominant in the container, and the period after the peak of the change amount ΔQ is the stage in which drying is dominant. After detecting the peak of the change amount ΔQ, the fermentation / drying apparatus of the present invention performs an operation mode different from that before the peak.

FIG. 7 shows an example in which the operation mode is divided into two before and after the peak of the change amount ΔQ. Specifically, the operation control from the raw material input to the removal is the operation mode 1 during the period from the raw material input until the change amount ΔQ reaches the peak, and the period from the change amount ΔQ reaching the peak to the extraction. It is divided into operation modes 2. In this case, the operation mode 1 is a fermentation-oriented operation mode in which the growth rate of microorganisms is extended without slowing down, and the operation mode 2 is a drying-oriented operation mode in which the weight loss due to the amount of water evaporation is increased. be. Table 1 shows the contents of each operation mode.

The unit air intake amount shown in Table 1 indicates the air intake amount per 1 m ³ of the processed material in the container and per minute. In addition, the displacement moves according to the fluctuation of the intake air volume. As shown in Table 1, the unit intake amount in the operation mode 1 is 0.25 to 0.35 m ³ / min · m ³ . In the early stage of the fermentation stage, the oxygen demand is generally large, so a certain amount of air intake is required. On the other hand, if the unit intake amount becomes too large, the surface of the particles of the fermentation raw material tends to dry, and the action of microorganisms may decrease. Therefore, the unit intake amount is set to a medium level.

Further, since the growth rate of the microorganism is maximized in the period until the change amount ΔQ reaches the peak, the intake air temperature (55 to 60 ° C.) is set according to the activation temperature of the microorganism. Further, during the same period, it is necessary to quickly mix the fermented raw material after charging and the processed product in the container to adjust the water content and pH to accelerate the start of fermentation. Therefore, the stirring frequency is slightly higher, and specifically, the ratio of the rotation time and the stop time in the intermittent operation is set to be about the same. If the stirring frequency is too high during this period, the added fermentation raw material tends to fall into the lower part of the container, so the ratio of rotation time to stop time in intermittent operation is 2: 1 to 1: 1.5. preferable.

On the other hand, the operation mode 2 in Table 1 is set to the operation conditions specialized for drying. Specifically, in the operation mode 2, the unit intake amount and the intake air temperature are set larger than those in the operation mode 1. As described above, since the period after the peak of the amount of change ΔQ is considered to be the stage of predominant drying, the amount of water evaporation can be increased by injecting a large amount of air at a relatively high air temperature. To accelerate the drying of the processed material. The intake air temperature can be raised, for example, by heating (ON / OFF) the air after the air supply blower with a heater or burner, or by increasing the heater output in a configuration in which the heater output can be adjusted. can. For example, the heater output is controlled by a temperature controller or the like based on the temperature measured by the temperature sensors provided at the points b and d in FIG. 2 and the temperature sensor provided between the heater 7 and the container 2 in FIG. The intake air temperature can be adjusted by doing so. Further, the unit intake amount can be increased, for example, by increasing the inverter frequency of the air supply blower.

Further, in the operation mode 2, the stirring blade is rotated in continuous operation, and the stirring frequency is higher than that in the operation mode 1. The stirring speed of continuous operation is, for example, about 2 rotations per hour. By increasing the stirring frequency, the air is evenly contacted with the processed product, and drying can be further promoted. The mode of increasing the stirring frequency as compared with the operation mode 1 is not limited to the continuous operation, for example, the intermittent operation in which the ratio of the rotation time is larger than that of the intermittent operation of the operation mode 1 (for example, rotation 18 minutes, stop 6 minutes). ) May be used. Further, the intermittent operation at the same time ratio as the intermittent operation of the operation mode 1 may be set, and the stirring speed at the time of rotation may be higher than that of the operation mode 1.

In the operation mode 2 of Table 1, both the unit intake amount and the intake air temperature are set to be large, but at least one of the unit intake amount and the intake air temperature may be set to be large. Further, in each operation mode, the unit intake amount and the intake air temperature do not have to be constant, and the operation mode 2 has a relationship in which at least one of the unit intake amount and the intake air temperature is larger than that of the operation mode 1. May be changed after satisfying. Further, the specific numerical values in Table 1 are not limited to this, and can be appropriately set in consideration of power consumption and energy consumption.

Further, in Table 1, the unit intake amount, intake temperature, and stirring frequency of the operation mode 2 are changed for each item of the operation mode 1, but other items may be further changed. For example, in view of the large oxygen demand of microorganisms in the initial stage of fermentation, the oxygen concentration of the intake air in the operation mode 1 may be higher than the oxygen concentration of the intake air in the operation mode 2. In this case, in the operation mode 1, the control to intentionally increase the oxygen concentration of the incoming air can be performed, and in the operation mode 2, such control can be prevented. Further, the humidity of the incoming air in the operation mode 2 may be smaller than the humidity of the incoming air in the operation mode 1. In this case, in the operation mode 2, the dry outside air is introduced into the container, which contributes to the efficiency of drying.

Next, the determination of the ΔQ peak will be described with reference to FIG. 7. As shown in FIG. 7, the ΔQ peak is the amount of change ΔQ at the timing when the amount of change ΔQ changes from the increasing tendency to the decreasing tendency. Therefore, the presence or absence of the ΔQ peak can be determined by calculating the change amount (slope) of the change amount ΔQ and determining whether or not the slope is less than the threshold value. If the slope is less than the threshold value, it is determined that there is a ΔQ peak, that is, the timing at which the change amount ΔQ changes from the increasing tendency to the decreasing tendency has been reached. If the slope is equal to or greater than the threshold value, it is determined that the ΔQ peak has not been reached. The value of the threshold value is not particularly limited, but is set to, for example, zero in consideration of the fact that the slope of ΔQ changes in the order of plus, zero, and minus before and after the ΔQ peak.

In order to improve the accuracy of determining the ΔQ peak, it is preferable to determine the ΔQ peak by adding other items. As shown in FIG. 7, when the change amount ΔQ reaches its peak, both the fermentation heat amount Q and the exhaust temperature tend to increase. Further, as shown in FIGS. 3 to 6, the exhaust temperature at the time when the change amount ΔQ reaches the peak is approximately around 60 ° C. In consideration of these, at least one of (a) the amount of heat Q for fermentation is increasing, (b) the exhaust temperature is increasing, and (c) the exhaust temperature is at least a predetermined temperature. Is preferably used for determining the ΔQ peak.

The determination in (a) above is based on the fact that the amount of change ΔQ in the amount of heat of fermentation is positive. The determination in (b) above is determined based on the fact that the exhaust temperature at that time is increased as compared with the exhaust temperature before a predetermined time. The determination in (c) above is based on the fact that the exhaust temperature at that time is, for example, 56 ° C. or higher. Further, it is more preferable that the determination of the ΔQ peak is performed on the condition that all of the above (a) to (c) are satisfied in addition to the slope of the change amount ΔQ.

FIG. 8 shows an example in which the operation mode is further subdivided as another operation control. In FIG. 8, the operation control from the input of the raw material to the removal of the raw material is performed in the operation mode 1 during the period from the input of the raw material to the peak of the change amount ΔQ, and from the time when the change amount ΔQ reaches the peak until the ΔQ becomes negative. It is divided into an operation mode 3 during the period of 1 and an operation mode 2 during the period from when the change amount ΔQ becomes negative until the extraction. In FIG. 8, unlike FIG. 7, an operation mode 3 is provided between the operation mode 1 and the operation mode 2. During this period, the exhaust temperature is almost constant at a high temperature, and in the operation mode 3, the operation of maintaining the exhaust temperature is performed. Table 2 shows the contents of each operation mode.

The contents of the operation mode 1 and the operation mode 2 shown in Table 2 are the same as the contents of Table 1. On the other hand, in the operation mode 3, since the exhaust temperature is maintained without rapidly increasing the growth rate of microorganisms, the unit intake amount and the intake temperature are smaller than those in the operation mode 1. Further, the stirring frequency is also smaller than that in the operation mode 1. By providing the operation mode 3 as a binder before the operation mode 2 in which emphasis is placed on drying, it is expected that the deactivation of microorganisms will be delayed and the amount of dry matter decomposed in fermentation will increase.

In the operation control of FIG. 8, the determination that ΔQ becomes negative is performed by determining whether or not ΔQ is less than zero. Further, in order to improve the accuracy of this determination, other items may be added. From FIG. 8, since the exhaust temperature is substantially constant when ΔQ becomes negative, for example, it may be determined that the amount of change in the exhaust temperature is within a predetermined range.

FIG. 9 shows a model diagram of the time transition of the exhaust temperature when the operation control of FIG. 8 is performed. As shown in FIG. 9, by combining the three operation modes, it is possible to perform air intake control that distinguishes between the fermentation stage and the drying stage. As a result, the exhaust temperature rises stepwise, and it is expected that the amount of dry matter decomposition and the amount of water evaporation will increase. In the operation mode 1, the exhaust temperature is rapidly raised by the intake control that emphasizes fermentation, in the operation mode 3, the exhaust temperature is maintained by suppressing the unit intake amount and the intake temperature, and in the operation mode 2, the unit intake is maintained. It promotes drying by increasing the amount and air temperature. The operation period of the operation mode 3 is preferably shortened in order to suppress power consumption.

On the other hand, the conventional operation control shown in FIG. 9 does not focus on fermentation and drying. For example, the exhaust temperature drops in the latter half of the fermentation drying process, and it is not always suitable for the drying stage. The conventional operation control here assumes, for example, constant control with a unit intake amount of 0.25 m ³ / min · m ³ and an intake temperature of 65 ° C.

In FIG. 8 above, the operation mode 3 is performed during the period from when the change amount ΔQ reaches the peak until when ΔQ becomes negative, but the operation period of the operation mode 3 is not limited to this. For example, the operation mode 3 may be performed during the period from the time when the amount of change ΔQ reaches the peak until the amount of change ΔQ drops sharply. This sharp drop indicates that the activity of the microorganism has decreased significantly, and in FIG. 8, the amount of change ΔQ from 23:00 to 0:00 has dropped sharply. This sharp drop is determined based on the fact that the slope of the change amount ΔQ decreases by a threshold value (for example, 3 MJ / h) or more.

Next, the calculation span of the amount of change ΔQ was examined. In FIGS. 3 to 9, the calculation span of the change amount ΔQ is 60 minutes. In the test on February 10 in FIG. 4, the calculation spans of the amount of change in the amount of heat of fermentation ΔQ were set to 10 minutes, 60 minutes, 120 minutes, 180 minutes, and 240 minutes, respectively, using the amount of heat of fermentation acquired at 1-minute intervals. FIG. 10 shows a correlation diagram between ΔQ and the exhaust temperature when the temperature is set to 300 minutes. For example, in the case of a calculation span of 60 minutes, the calculation means acquired the amount of heat of fermentation every minute, and calculated the difference between the amount of heat of fermentation at present (at the time of acquisition) and the amount of heat of fermentation at the time before 60 minutes as ΔQ.

As shown in FIG. 10, in the case of the calculated span of 10 minutes and 60 minutes, it was relatively difficult to grasp the inflection point of the change amount ΔQ. On the other hand, in the case of the calculated spans of 120 minutes, 180 minutes, 240 minutes, and 300 minutes, the entire plot shows circularity, and the inflection point can be easily grasped. From the results of FIG. 10, the calculated span is preferably 120 minutes to 300 minutes, more preferably 180 minutes to 240 minutes.

In the fermentation drying method of the present invention, the change amount tends to decrease from an increasing tendency based on the calculation step of calculating the change amount of the fermentation calorific value at an arbitrary time interval of the fermentation drying apparatus and the calculated change amount of the fermentation calorific value. Before the timing is determined, at least one of the items of the amount of outside air introduced into the container and the temperature of the outside air after the timing is determined by the determination step and the determination process for determining the timing of change to It has an operation control step that is larger than the item, and each of the above steps may be automatically performed by using a means provided in the fermentation / drying device, for example, a control device 15 (see FIG. 1). , All or part of the process may be performed manually. In the latter case, for example, the calculation step and the determination step may be performed by the control device 15 of the fermentation / drying device, and the operation mode may be switched manually as the operation control step.

The fermentation and drying apparatus of the present invention can control the air intake according to each of the fermentation stage and the drying stage in the fermentation and drying process from the input to the removal of the fermentation raw material, and can efficiently carry out the fermentation and drying. For example, it can be suitably used as an apparatus for fermenting and drying organic waste.

1, 1'Fermentation and drying device 2 Container 2a Input port 2b Outlet 2c Exhaust port 3 Rotating shaft 4, 4A, 4B Stirring blade 4a Vent hole 5 Machine room 6, 6A, 6B Air supply blower 7 Heater 8 Hydraulic cylinder 9 Exhaust means 10 Exhaust pipe 11 Exhaust blower 12 Deodorizer 13 Temperature sensor 14 Control panel 15 Control device 16A, 16B Filter

Claims (6)

A rotating shaft provided inside the container, a plurality of stirring blades attached to the rotating shaft, an air supply means for taking in outside air into the container, and an exhaust gas for discharging the inside air accumulated in the container to the outside of the container. It is a closed-type fermentation / drying device equipped with means.
The fermentation drying device introduces outside air into the container by the air supply means, exhausts the inside air from the container by the exhaust means, and ferments and dries the fermentation raw material while stirring with the stirring blade. It is a device
The fermentation drying device determines the timing at which the amount of change changes from an increasing tendency to a decreasing tendency based on the calculated means for calculating the amount of change in the amount of heat of fermentation at an arbitrary time interval and the calculated amount of change in the amount of heat of fermentation. The timing is determined by the determination means and at least one of the items of the amount of outside air introduced into the container and the temperature of the outside air introduced into the container after the timing is determined by the determination means. A fermentation / drying apparatus comprising: an operation control means for performing an operation mode in which the item is made larger than the item before the determination. The operation control means is characterized in that, in the operation mode, at least one item of the stirring frequency and the stirring speed of the stirring blade is made larger than the item before the timing is determined. 1 The fermentation drying apparatus according to 1. The determination means calculates the gradient of the amount of change in the amount of heat of fermentation, the gradient is less than the threshold value, the amount of heat of fermentation is increasing at that time, and the temperature of the inside air is increasing. The fermentation drying apparatus according to claim 1 or 2, wherein the timing is determined on condition that at least one of the above and the temperature of the inside air is equal to or higher than a predetermined temperature is satisfied. The operation control means has the amount of outside air introduced into the container, the temperature thereof, and the stirring in a predetermined period after the timing is determined by the determination means and before the operation mode is performed. The one according to any one of claims 1 to 3, wherein at least one of the stirring frequency of the blade and the stirring speed thereof is made smaller than the item before the timing is determined. Fermentation and drying equipment. The fermentation drying apparatus according to claim 4, wherein the predetermined period is a period from after the timing is determined by the determination means until the amount of change in the amount of heat of fermentation becomes negative. A rotating shaft provided in the container, a plurality of stirring blades attached to the rotating shaft, an air supply means for taking in outside air into the container, and an exhaust for discharging the inside air accumulated in the container to the outside of the container. It is a fermentation and drying method in a closed type fermentation and drying device provided with means.
The fermentation drying device introduces outside air into the container by the air supply means, exhausts the inside air from the container by the exhaust means, and ferments and dries the fermentation raw material while stirring with the stirring blade. It is a device
In the fermentation drying method, a calculation step of calculating the amount of change in the amount of heat of fermentation at an arbitrary time interval and a timing at which the amount of change changes from an increasing tendency to a decreasing tendency based on the calculated amount of change in the amount of heat of fermentation are determined. After the timing is determined by the determination step and the determination step, at least one of the items of the amount of outside air introduced into the container and the temperature of the outside air introduced into the container is determined by the timing. A fermentation and drying method characterized by having an operation control step that is larger than the previous item to be determined.

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