JP2021159807A - Fermentation drying method, cement production method and method for using fermented dried matter - Google Patents

Abstract

To provide a fermentation drying method enabling fermentation drying of a fermentation raw material to be performed using an index suitable for each operation management, and to provide a cement production method.SOLUTION: A fermentation drying method comprises: a first calculation step of calculating a first fermentation index of at least one of fermentation heat amount, inside air temperature and generation speed of carbon dioxide using a hermetic type fermentation drying device comprising a rotary shaft 3 and a plurality of agitation blades 4 provided in a container 2, an air blower 6 and air exhaustion means 9; a first adjustment step of adjusting the outside air amount introduced in the container 2 based on the first fermentation index; a second calculation step of calculating a weight reduction speed being a weight reduction per unit time as a second fermentation index based on the weight of the fermentation raw material calculated by a weight sensor 13; and a second adjustment step of adjusting at least one of the charge amount of the fermentation raw material, composition thereof and the discharge amount of a fermented dried material based on the weight reduction speed calculated in the second calculation step.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for fermenting and drying, a method for producing cement, and a method for using a fermented and dried product.

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

In the fermentation / drying apparatus, the input amount of the fermentation raw material, the composition of the fermentation raw material, the discharge amount of the fermented dried product, and the like are adjusted according to the temperature distribution in the container. However, since the temperature distribution in the container fluctuates greatly, there is a limit to using it as a control index such as the input amount of fermentation raw materials. For example, in the fermentation and drying of sewage sludge, a high-calorie material such as waste white clay or a high heat-generating raw material is often blended as a fermentation aid, and the fermentation status changes depending on the blending ratio of the fermentation aid. However, it is difficult to grasp the fermentation status only from the temperature distribution in the container. For example, even if the fermentation status is estimated from the quality of the discharged fermented dried product and the input amount of the fermentation raw material is adjusted, even if it is adjusted. It may be too late to grasp the situation in the event of poor fermentation.

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 evaporated per predetermined time are used as fermentation indexes, and the amount of outside air introduced into the container is adjusted based on the fermentation indexes. The amount of heat of fermentation and the amount of water vaporized, which are 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

By the way, in the fermentation and drying process, the amount of air intake is adjusted in a short-term cycle (for example, in units of hours and minutes), whereas operations such as inputting fermentation raw materials and discharging fermented and dried products from a container are long-term. It is generally performed in a typical cycle (for example, on a daily basis). Although the amount of heat of fermentation, which is the fermentation index of Patent Document 1, is effective for short-term operation control such as adjustment of the amount of air intake, it is not necessarily suitable for long-term operation control such as adjustment of the input amount of fermentation raw materials. I can't say that.

The present invention has been made to deal with such a problem, and by using an index suitable for each operation control, a fermentation and drying method capable of more stably fermenting and drying the fermentation raw material, and the production of cement. The purpose is to provide a method.

In the fermentation and drying method of the present invention, 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 inside air accumulated in the container are used. It is a fermentation and drying method in a closed type fermentation and drying device provided with an exhaust means for discharging to the outside of the container. It is a device that exhausts the inside air from the container by the exhaust means, ferments and dries the fermentation raw material to be put into the container while stirring with the stirring blade, and discharges the fermented dried product. The apparatus has a weight sensor that directly or indirectly calculates the weight of the fermentation raw material in the container, and the fermentation / drying method is based on the amount of heat of fermentation in the fermentation / drying apparatus and the amount of the inside air discharged by the exhaust means. In the first calculation step of calculating at least one first fermentation index of the temperature (exhaust temperature) and the generation rate of carbon dioxide in the fermentation / drying apparatus, and the first fermentation index calculated in the first calculation step. Based on the first adjustment step for adjusting the amount of outside air (intake amount) introduced into the container and the weight of the fermentation raw material calculated by the weight sensor, the weight is reduced per unit time. Based on the second calculation step of calculating the reduced weight rate as the second fermentation index and the reduced weight rate calculated in the second calculation step, the input amount of the fermentation raw material, the composition of the fermentation raw material, and the above It is characterized by having a second adjusting step for adjusting at least one of the emissions of the fermented dried product.

The first calculation step is a step of calculating the temperature of the inside air as the first fermentation index, and the first adjustment step is a temperature range to which the temperature of the inside air belongs among a plurality of divided temperature ranges. It is characterized in that the amount of the outside air is adjusted accordingly.

The first calculation step is a step of calculating the fermentation heat amount and the temperature of the inside air as the first fermentation index at predetermined time intervals, and the first adjustment step is a step of calculating the fermentation heat amount and the inside air at an arbitrary calculation. When the temperature increases with respect to both the heat of fermentation calculated last time and the temperature of the inside air, the amount of the outside air is increased, and the heat of fermentation and the temperature of the inside air at an arbitrary calculation are calculated at the previous time. It is characterized in that the amount of the outside air is reduced when both the amount of heat of fermentation and the temperature of the inside air are reduced.

The exhaust means has a wet deodorizing device that performs a treatment related to the inside air, and a concentration sensor and exhaust that acquire information on the concentration of carbon dioxide contained in the inside air in an exhaust path downstream of the wet deodorizing device. A flow rate sensor for acquiring information on the flow rate is provided, and the first calculation step is based on the concentration sensor and the information on the carbon dioxide concentration and the exhaust flow rate acquired by the flow rate sensor. It is characterized in that the generation rate of carbon dioxide is calculated as a fermentation index. Further, instead of providing the exhaust gas flow rate sensor, the air supply flow rate may be used instead of the exhaust gas flow rate based on the dry gas by adding a function of maintaining the pressure of the container (fermenter) at a slightly negative pressure. The air supply flow rate may be a measurement result by a flow rate sensor, or a flow rate estimated from the rotation speed of the air supply means (for example, an air supply blower) may be used.

The fermentation-drying method is a method in which a cycle of adding the fermentation raw material to the fermentation-drying apparatus and taking out a part of the fermentation-dried product once a day is carried out for two days or more, and the second calculation step is performed. When the weight loss rate in any time zone calculated in the above increases with respect to the weight loss rate in the same time zone on the previous day, both the input amount of the fermentation raw material and the discharge amount of the fermented dried product are both. Or, if either one is increased and decreased, either the input amount of the fermentation raw material and the discharge amount of the fermented dried product are decreased, or the addition amount of the fermentation aid is increased. It is characterized by changing the type of fermentation aid.

The fermentation raw material is characterized by containing sewage sludge.

The method for producing cement of the present invention is characterized in that cement is produced from a fermented and dried product obtained by the fermented and dried product of the present invention as a raw material.

The method of using the fermented dried product of the present invention is characterized in that the fermented dried product obtained by the fermented dried product of the present invention is used as a heat energy source.

The fermentation and drying method of the present invention uses a closed fermentation and drying apparatus, and the amount of air intake introduced into the container based on at least one first fermentation index of fermentation heat quantity, exhaust temperature, and carbon dioxide generation rate. And adjust the amount of fermentation raw material input based on the reduced weight rate (second fermentation index). The first fermentation index fluctuates greatly even in a short period of time and reflects the short-term fermentation state at that time, whereas the weight related to the decrease weight rate of the second fermentation index hardly changes in a short period of time. It can be said that it is suitable for grasping the long-term fermentation state. Therefore, by adjusting the operation operation performed in the short-term cycle and the operation operation performed in the long-term cycle based on different fermentation indexes, fermentation and drying of the fermentation raw material can be carried out more stably.

It is a vertical cross-sectional view which shows an example of the fermentation drying apparatus which concerns on this invention. This is an example of frequency control showing the relationship between each temperature region and frequency. It is a figure which shows the setting screen of the frequency control of FIG. It is a flowchart which shows the processing procedure of the adjustment of the inverter frequency. It is a figure which shows the installation position of the weight sensor. It is a figure which shows the setting screen of the short-term control of Example 1. FIG. It is a figure which shows the change of the exhaust temperature in the fermentation drying method of Example 1. It is a figure which shows the change of the weight in the fermentation drying method of Example 1. It is a figure which shows the change of the frequency and the like in the fermentation drying method of Example 1. It is a figure which shows the change of the weight in the fermentation drying method of Example 2.

The outline of the fermentation / drying apparatus according to 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 the fermentation / drying apparatus. As shown in FIG. 1, the fermentation / drying apparatus 1 includes a cylindrical vertical container 2, a rotating shaft 3 provided in the container 2 in the vertical direction, and a plurality of agitators provided in multiple stages around the rotating shaft 3. A closed vertical type including wings 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 rotating 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 rotation 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 lower part has an outlet 2b for the fermented and 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 rotating shaft 3 penetrates into the machine room 5 and is rotated by a hydraulic cylinder 8 at a predetermined rotation speed. As the air supply blower 6, it is preferable to use a blower whose rotation speed can be controlled by the inverter frequency in order to make it possible to adjust the amount of incoming air. Further, an air supply valve for adjusting the amount of air supply may be provided in the middle of the pipe 6a.

Gas, water vapor, etc. 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 wet deodorizing device 12. The exhaust blower 11 forcibly exhausts gas or the like in the container. The wet deodorizing device 12 is a device that performs a treatment related to the inside air, and is, for example, an absorption tower that captures an odor component by bringing water or an acid as a cleaning liquid into contact with a gas or the like. Examples of the odor component include lower fatty acids such as propionic acid, normal butyric acid, and isovaleric acid, and ammonia.

In the exhaust pipe 10, a temperature sensor 14 for detecting the temperature of the inside air discharged from the container 2 is provided on the exhaust path from the exhaust port 2c to the exhaust blower 11. Further, on the exhaust path downstream of the wet deodorizing device 12, a temperature sensor 15 for detecting the temperature of the gas after processing by the wet deodorizing device 12, a flow rate sensor 16 for detecting the flow rate of the gas, and the gas. An oxygen sensor 17 for detecting the oxygen concentration of the gas and a pressure sensor 18 for detecting the pressure (pressure) of the gas are provided. The oxygen sensor 17 is provided as a concentration sensor for acquiring information related to the concentration of carbon dioxide, and a carbon dioxide sensor may be provided instead of the oxygen sensor.

Further, the fermentation / drying apparatus 1 has a weight sensor 13 that directly or indirectly calculates the weight of the fermentation raw material (hereinafter, also referred to as the content) inside the container 2. In FIG. 1, a plurality of weight sensors 13 are provided on the outer bottom surface of the apparatus main body 1a having the container 2 and the machine room 5. The weight sensor 13 is also called a load cell and is a sensor for measuring a load. In the embodiment of FIG. 1, the weight sensor 13 detects the weight of the apparatus main body 1a including the fermentation raw material. The weight of the fermentation raw material in the container can be indirectly calculated by subtracting the weight of the apparatus main body 1a in the state where there is no fermentation raw material in the container (the container 2 is empty) from the detected weight. By providing a weight sensor at the lower part of the container, the weight of the fermentation raw material in the container can be calculated directly. The weight sensor 13 is preferably installed on a highly rigid and horizontal foundation with less vibration. For example, when it is installed in an outdoor environment, it is installed on a foundation such as concrete or an iron plate.

Further, although omitted in FIG. 1, on the air supply path, a temperature sensor that detects the temperature of the air introduced into the container 2, a flow sensor that detects the flow rate of the air introduced into the container 2, and the container 2 are introduced. A pressure sensor or the like for detecting the pressure of air is provided.

As described above, the fermentation / drying apparatus 1 is provided with various sensors for confirming its operation. The control device 20 acquires the detection results of these sensors as output signals and performs various controls based on the detection results. The control device 20 is mainly composed of a microcomputer composed of a well-known CPU, ROM, RAM, and the like. The control device 20 has a configuration in which various detection results can be continuously acquired and stored, and also has various calculation functions.

In FIG. 1, the control device 20 is provided in a control panel 19 that controls the operation of the fermentation / drying device 1. With the control panel 19, 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).

In the fermentation and drying apparatus according to the present invention, livestock excrement, food waste, sewage sludge and the like can be used as the fermentation raw material to be subjected to the fermentation and drying treatment, and it is preferable that the fermentation raw material contains sewage sludge. Sewage sludge is sludge generated in a purification facility that purifies sewage such as domestic wastewater. The water content of the sewage sludge used as a fermentation raw material is, for example, 70% by mass to 90% by mass, preferably 75% by mass to 85% by mass. The fermentation and drying treatment in the fermentation and drying apparatus is carried out by aerobic fermentation in a container in the presence of aerobic fermenting bacteria while aerating. As the aerobic fermenting bacterium, a fermenting bacterium that is activated at about 30 to 90 ° C. is preferable, and examples thereof include the genus Geobacillus and the genus Bacillus.

When the sewage sludge is fermented and dried, it is preferable to add meat-and-bone meal, coal ash, and seed sludge to the sewage sludge as a fermentation raw material. As specific values, sewage sludge is 70% by mass to 85% by mass, meat-and-bone meal is 10% by mass to 20% by mass, coal ash is 5% by mass to 20% by mass, and seed sludge is the total amount of fermented raw materials. It is preferably contained in an amount of 1% by mass to 5% by mass. Coal ash refers to fly ash and clinker ash generated as by-products in coal-fired power plants and the like. Seed sludge is sludge compost or dry sludge containing eutrophic fermenting bacteria (aerobic microorganisms). In addition, the fermentation raw material may further contain slaked lime, waste white clay, and the like.

In the fermentation / drying apparatus 1 of FIG. 1, the fermentation raw material is put into the inside of the container 2 from the inlet 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. The water content of the fermented dried product is, for example, 10% by mass to 40% by mass, preferably 15% by mass to 30% by mass. In fermentation and drying, the outside air is introduced from the ventilation hole 4a of the lowermost stirring blade by the air supply blower 6 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 blade is used. 4 is rotated at a low speed, and sewage sludge or the like, which is a fermentation raw material, is agitated and agitated 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.

As an operation procedure, first, the fermentation raw material is put 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 charged 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-mentioned input 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, and the treatment is continuously performed. The obtained fermented dried product is usually in the form of smooth powder.

The fermentation and drying method of the present invention is roughly classified into (1) calculating at least one fermentation index of fermentation calorific value, exhaust temperature, and carbon dioxide generation rate, and adjusting the amount of air intake based on the calculated fermentation index. Based on the process and (2) the weight of the fermentation raw material, the reduced weight rate ΔW / t is calculated as a fermentation index, and based on the calculated ΔW / t, the input amount of the fermentation raw material, the composition of the fermentation raw material, and It has a step of adjusting at least one of the emissions of the fermented dried product. Normally, the adjustment of the amount of air intake according to the above (1) is performed on an hour and minute basis, and the adjustment of the fermentation raw material and the like according to the above (2) is performed on a daily basis. Due to such a time difference, the element related to (1) is also referred to as “short term” and the element related to (2) is also referred to as “long term” in the present specification.

Hereinafter, the four methods (a) to (d) for short-term control will be described in order. In this short-term control, the amount of air intake is adjusted using a short-term fermentation index. The amount of air intake can be adjusted, for example, by increasing or decreasing the inverter frequency of the air supply blower. Further, in a configuration provided with an air supply valve capable of adjusting the amount of air supply, the opening degree of the air supply valve may be increased or decreased to adjust the amount of air intake. In the following, control using the inverter frequency will be described.

(A) Short-term control method using the exhaust temperature as an index The exhaust temperature detected by the temperature sensor 14 shown in FIG. 1 is about 30 ° C. to 70 ° C. Since fermentation is more active as the exhaust temperature is higher, it is preferable to increase the inverter frequency to increase the amount of air intake when the exhaust temperature is high. For example, the frequency control may be proportional control in which the inverter frequency is increased at a constant rate as the exhaust temperature rises in the entire temperature range, or control may be performed according to each of a plurality of temperature regions. In the present invention, the latter frequency control is particularly preferable. In this case, the plurality of temperature regions is, for example, three or more, preferably five or more.

FIG. 2 shows an example of frequency control in which the exhaust temperature is divided into six regions. The circled numbers in the figure represent each stage. In this frequency control, in the region where the exhaust temperature is less than 40 ° C. (stage 1) and the region where the exhaust temperature is 60 ° C. or higher (stage 6), the frequency is constant and the exhaust temperature is 40 ° C. or higher and lower than 60 ° C. (stage 6). In stages 2 to 5), proportional control is performed. Further, the proportionality constants (slopes) of the proportional controls of the stages 2 to 5 are different from each other. Each proportionality constant increases in the order of stage 2, stage 4, stage 5, and stage 3. In this way, by dividing the temperature range of the exhaust temperature into a plurality of temperature ranges and combining a constant control and a plurality of proportional controls having different proportionality constants, it is possible to supply air more suitable for the fermentation state.

FIG. 3 shows an example of the frequency control setting screen of FIG. This setting screen is displayed on the screen of the control panel. The left side of FIG. 3 is a table displaying items of the stage (temperature range), the exhaust temperature, and the inverter frequency, and the exhaust temperature and the inverter frequency, which are the boundary values between the stages, can be set respectively.

Further, on the right side of FIG. 3, items of the waiting time for stage transition and the sampling cycle are displayed. For example, in a state belonging to an arbitrary stage, if the current exhaust temperature falls below the boundary value with the adjacent low temperature side stage, the stage shift is determined after the standby time elapses without immediately shifting to that stage. do. Then, depending on the determination result, the stage is shifted or stayed.
During this standby time, the exhaust temperature is collected for each sampling cycle, and the average exhaust temperature _Tav during the standby time is calculated. Then, the transition of the stage is determined by comparing the calculated average exhaust temperature _{Tav with the exhaust temperature Tpre} immediately before the standby time. For example, if the average exhaust temperature T _av is smaller than the exhaust temperature T _pre, the stage shifts to the adjacent low temperature side stage, and if not, the current stage is stayed. By determining whether or not the transition is possible after the standby time has elapsed in this way, it is possible to eliminate frequency disturbance due to variations in the exhaust temperature for each arbitrary temperature zone. That is, it can be said that the step of determining whether or not this transition is possible is the exhaust temperature correction mode. The standby time and the sampling cycle during that time can be set as appropriate.

Here, the inverter frequency adjustment process by the control device will be described with reference to the flowchart of FIG. The process from the start to the end of FIG. 4 is repeatedly performed at predetermined time intervals (for example, every 3 minutes). The processes from steps S11 to S14 are performed instantaneously.

First, in step S11, the exhaust temperature T detected by the temperature sensor is acquired. In the following step S12, it is determined to which region the acquired exhaust temperature T belongs. Specifically, it is determined whether or not the exhaust temperature T is less than each boundary value in order from the boundary value having the highest temperature. For example, in FIG. 2, when the exhaust temperature T is less than 48 ° C. and not less than 40 ° C., the stage 2 is determined.

In step S13, it is determined whether or not the region determined in step S12 is the same region as the region determined last time. If they are in the same region (when step S13 is Yes), the frequency is set in the same region (step S14). For example, in FIG. 2, in the case of the stage 2, the frequency is set to 31 Hz when the exhaust temperature T is 44 ° C. Further, in the case of the stage 5, the frequency is set to 48 Hz when the exhaust temperature T is 59 ° C.

When step S13 is No, that is, when the region determined this time is different from the region determined last time, the process proceeds to the step of determining whether or not the transition is possible. First, in step S15, the inverter frequency is fixed to the frequency of the boundary value between the two regions. For example, in FIG. 2, when the region determined last time is the stage 2 and the region determined this time is the stage 3, the inverter frequency is fixed at 32 Hz, which is the boundary value between the stage 2 and the stage 3.

When the inverter frequency is fixed, it is fixed at that frequency until a predetermined standby time elapses. During this standby time, the average exhaust temperature _Tav is acquired (step S17). For example, in the case of the setting of FIG. 3, the exhaust temperature T is acquired every 10 seconds during the standby time of 5 minutes, and the average exhaust temperature _Tav in the 5 minutes is acquired.

When the waiting time ends (step S18), it is determined in step S19 whether or not the transition is possible. This determination is performed, for example, by determining the magnitude of _{the exhaust temperature T pre} immediately before the standby state and the average exhaust temperature T _{av acquired in step S17.} For example, whether or not the transition from an arbitrary region to the high temperature side region is possible is determined when the average exhaust temperature _Tav is larger than the exhaust temperature _Tpre , that is, when the exhaust temperature tends to rise, and when it is not ( It is determined that the transition to _{T av} ≤ T _{pre) does not occur.} On the other hand, whether or not the transition from an arbitrary region to the low temperature side region is possible is determined when the average exhaust temperature _Tav is smaller than the exhaust temperature _Tpre , that is, when the exhaust temperature tends to decrease, and when it is not ( It is determined that the transition to _{T av} ≥ T _{pre) does not occur.} As another method for determining whether or not the transition is possible, it may be determined that the exhaust temperature T shifts to the different temperature region when the state in which the exhaust temperature T belongs to a temperature region different from the arbitrary temperature region continues for a predetermined time. ..

When step S19 is Yes, the area is changed to the adjacent area (step S20), and the inverter frequency is set according to the proportional control in the changed area (step S21). If step S19 is No, the current region is maintained.

As described above, although the inverter frequency adjustment process is shown in FIG. 4, the adjustment process by the control device is not limited to this. For example, the process of determining the region transition (steps S15 to S21) may be omitted, and the frequency may be set according to the region determined each time. However, when shifting from an arbitrary temperature range to a different temperature range, as shown in FIG. 4, it is preferable to fix the frequency for a predetermined standby time and then determine whether or not the shift is possible. This makes it possible to prevent the frequency from fluctuating significantly due to transient erroneous detection of temperature or temperature fluctuation.

(B) Short-term control method using the amount of heat of fermentation as an index The amount of heat of fermentation was calculated from the following formula (1) according to Patent Document 1.

The exhaust enthalpy in the above formula (1) was calculated from the formula of (A) water vapor enthalpy in exhaust + (B) dry air enthalpy.
(A) The exhaust (water vapor) enthalpy was calculated from the normal-converted exhaust (water vapor) flow rate, water molecular weight, standard state molar volume, and saturated steam ratio enthalpy. The saturated vapor ratio enthalpy was obtained from an approximate expression created by plotting the dataset of the saturated vapor table. The relative humidity (% RH) at the time of calculating the exhaust (water vapor) flow rate converted into normal was fixed at 100% RH.
(B) The exhaust (dry air) enthalpy was calculated from the normal equivalent exhaust (dry air) flow rate, dry air molecular weight, standard molar volume, air specific heat, and exhaust temperature.

The air supply enthalpy in the above formula (1) was calculated from the formula (A) water vapor enthalpy + (B) dry air enthalpy during air supply.
(A) The air supply (water vapor) enthalpy was calculated from the normal conversion air supply (water vapor) flow rate, water molecular weight, standard state molar volume, and saturated steam ratio enthalpy. The saturated vapor ratio enthalpy was obtained from an approximate expression created by plotting the dataset of the saturated vapor table. The relative humidity (% RH) at the time of calculating the normalized air supply (water vapor) flow rate was fixed at 75% RH.
(B) The air supply (dry air) enthalpy was calculated from the normal conversion air supply (dry air) flow rate, the dry air molecular weight, the standard molar volume, the specific heat of the air, and the air supply temperature.

[Air supply flow rate (inflow rate)]
The air supply flow rate in the above was calculated from the following equation (2) based on the linear relationship between the inverter frequency for controlling the blower rotation speed of the air supply blower and the air supply flow rate.

The relative humidity (% RH) at the time of calculating the exhaust (water vapor) flow rate converted to normal was fixed at 100% RH.

An example of setting control parameters is shown below. For example, the amount of heat of fermentation is calculated at intervals of 3 minutes, and the amount of heat of fermentation A 3 minutes ago is compared with the current amount of heat of fermentation B. When the amount of heat of fermentation B is decreasing (B <A), the amount of air intake is decreased, and when these are equal (B = A), the amount of air intake is maintained. The amount of air intake can be increased or decreased by increasing or decreasing the inverter frequency of the blower (± 0.2 Hz). In this case, the amount of heat of fermentation is calculated during the interval of changing the inverter frequency.

(C) Short-term control method using the amount of heat of fermentation and the exhaust temperature as indicators As the improvement method of the above (b), both the amount of heat of fermentation and the exhaust temperature may be used as short-term indicators. That is, when both the fermentation heat amount and the exhaust temperature are increasing, the air supply amount by the air supply blower is increased, and when both the fermentation heat amount and the exhaust temperature are decreasing, the air supply amount by the air supply blower is decreased. It may be configured to be allowed.

(D) Short-term control method using the carbon dioxide generation rate as an index The information related to the concentration of carbon dioxide contained in the exhaust gas is acquired by a sensor (oxygen sensor 17 in FIG. 1) provided on the exhaust path. The rate of carbon dioxide generation in the container may be calculated, and the amount of air intake may be adjusted using this as an index.

As described above, by adjusting the amount of air intake introduced into the container using the fermentation indexes shown in the above (a) to (d), air is supplied with good followability according to the short-term fermentation state. It is possible to stably carry out fermentation and drying of the fermentation raw material. The amount of air intake may be adjusted by combining the fermentation indexes shown in (a) to (d) above.

For example, it is conceivable to combine (a) and (c). The control using the exhaust temperature as a short-term index in (a) is an absolute control in which the inverter frequency is determined according to the set temperature range. In the case of absolute control, the followability of the inverter frequency with respect to the exhaust temperature is good, but since the fluctuation range of the inverter frequency becomes large, the fluctuation range of the exhaust temperature tends to increase accordingly.

On the other hand, the control using the fermentation heat amount and the exhaust temperature as the short-term index in (c) above is a relative control in which the inverter frequency is determined in comparison with the past fermentation heat amount and the exhaust temperature. In the case of relative control, the fluctuation range of the inverter frequency is small, so the fluctuation range of the exhaust temperature is small. Further, depending on the exhaust temperature, if the exhaust temperature tends to rise, the followability of the inverter frequency may decrease. Therefore, by combining (a) and (c), it is possible to perform controls that complement each other. In this case, either (a) or (c) is used as the base control, for example, when the exhaust temperature tends to rise, the control (a) is used, and when the exhaust temperature tends to decrease, the control is performed. It is conceivable to control (c).

Next, operation management based on long-term indicators will be described. As a long-term fermentation index, the weight loss rate ΔW / t, which is the weight loss per unit time, is used to adjust the fermentation raw materials and the like. In the container (fermentation tank), as the fermentation progresses, the organic matter decomposes and the water evaporates due to the heat of fermentation, and as a result, the weight of the contents decreases. Therefore, the change in weight of the contents is considered to be effective as a fermentation index.

In FIG. 1, the reduced weight rate ΔW / t is calculated based on the weight of the fermentation raw material calculated by the weight sensor 13. The calculation of ΔW / t is performed by, for example, the control device 20. The control device 20 repeatedly acquires the weight (calculated value) of the fermentation raw material at an arbitrary acquisition interval (for example, 1 minute interval). Then, each time it is acquired, the difference between the weight of the fermentation raw material at the present time and the weight of the fermentation raw material at the time before a predetermined time is taken, and the difference is divided by the time difference to reduce the weight reduction rate as a fermentation index. Calculate ΔW / t.

In the present invention, the time interval between the current time point and the time point before a predetermined time in the calculation of ΔW / t is referred to as a calculation span. Although the calculation span can be set as appropriate, the weight of the fermentation raw material does not change significantly in a few minutes from the evaporation rate of water and the decomposition rate of the fermentation raw material, and in the present invention, ΔW / t is set as a long-term fermentation index. The calculated span may be an interval of about 1 hour to 24 hours, or a long-term span of about 1 week. The unit of ΔW / t is, for example, kg / min.

In the fermentation and drying process of the fermentation and drying apparatus, the fermentation raw material is added once a day, and an operation method is often used in which the addition time, the amount and composition of the fermentation material are fixed to some extent. When the same operation is performed every day in this way, for example, the weight loss rate in an arbitrary time zone is compared with the weight loss rate in the same time zone on the previous day, and the amount of the fermentation raw material input is increased or decreased depending on the magnitude. It is possible to change the composition of the fermentation raw material and adjust the increase / decrease in the amount of the fermented dried product discharged. Changes in the composition of fermentation raw materials include, for example, increasing or decreasing auxiliary materials and fermentation auxiliaries. The same time zone is not limited to the exact same time zone, but includes a time zone in which more than half of the time zones overlap.

Specifically, the weight loss rate in any time zone of the day (for example, the time zone from 18:00 to 6:00 the next day) is the same time zone of the previous day (for example, the time zone from 18:00 to 6:00 the next day). When it increases with respect to the rate of decrease in weight in, the input amount of the fermentation raw material or the discharge amount of the fermented dried product is increased from the input amount or the discharge amount of the previous day. As a specific numerical value, the amount is 105% to 120% of the input amount or the emission amount on the previous day. In this case, since the fermentation of the fermentation raw material is promoted, it is possible to increase the input amount or the discharge amount. The input amount and the discharge amount may be increased. On the other hand, when the weight loss rate in any time zone of the day decreases with respect to the weight loss rate in the same time zone of the previous day, the input amount of the fermentation raw material is reduced or the addition amount of the fermentation aid is increased. .. As a specific numerical value, the amount is set to 80% to 95% of the input amount of the fermentation raw material on the previous day. In this case, since the fermentation state of the day is lower than that of the previous day, the fermentation state can be improved by reducing the amount of the fermentation raw material input or increasing the amount of the fermentation aid.

Auxiliary materials are materials for stably promoting aerobic fermentation of fermentation raw materials, and specifically, materials for adjusting the water content and pH of fermentation raw materials, materials for improving air permeability, and the like. be. Examples of auxiliary materials include meat-and-bone meal, coal ash, slaked lime, and waste white clay.

Examples of the fermentation aid include chicken manure. As the chicken manure, in addition to the unfermented chicken manure, fermented chicken manure obtained by subjecting the chicken manure to an aerobic fermentation treatment can be used. The water content of fermented chicken manure is reduced by the fermentation treatment, and the water content is usually less than 30% by mass. As the fermented chicken manure, primary fermented chicken manure, secondary fermented chicken manure and the like can be used, but primary fermented chicken manure is preferable from the viewpoint of promoting fermentation. In addition, all of the above-mentioned chicken manure includes egg-collecting chickens and meat chickens.

As a method of increasing the amount of the fermentation aid added, for example, there is a method of adding fermented chicken manure. As one form, the amount of fermented chicken manure added is 3% by mass or more, preferably 3% by mass to 30% by mass, and more preferably 3% by mass to 20% by mass, based on the total amount of fermented raw materials in the container. be. As another form, the amount of fermented chicken manure added is 3% by mass to 20% by mass with respect to the sewage sludge charged into the container. As shown in Examples described later, fermentation can be promoted by adding fermented chicken manure.

Further, as another method using the reduced weight rate, the amount of the fermentation raw material input depends on the degree of deviation between the reduced weight rate ΔW / t at an arbitrary time zone of the day and the set target value ΔW / t _target. The increase / decrease in the amount of fermented dried matter may be adjusted, the composition of the fermented raw material may be changed, and the amount of the fermented dried product discharged may be adjusted.

In the fermentation / drying process by the fermentation / drying apparatus 1, the rotating shaft 3 is not constantly rotating, and repeats rotating and non-rotating. That is, the fermentation / drying apparatus 1 intermittently rotates the rotation shaft 3 to ferment and dry the fermentation raw material. When the rotating shaft 3 is rotating (when the hydraulic cylinder 8 is driven), vibration may occur as the piston of the hydraulic cylinder 8 expands and contracts. Further, it is considered that the stirring blade 4 rotates with the rotation of the rotating shaft 3, so that the fermentation raw material is separated and crushed, so that a load is applied downward in the vertical direction. In the configuration of FIG. 1, since the weight sensor 13 is arranged so as to receive the load of the device main body 1a including the container 2 and the hydraulic cylinder 8, there is a possibility of detecting the vibration and the load change of the hydraulic cylinder 8 during rotation. be. As a result, it may affect the detection of the weight of the fermentation material.

In consideration of such an influence, it is preferable that the fermentation / drying apparatus 1 has a noise removing means for removing noise from the calculated value of the weight of the fermentation raw material calculated by the weight sensor 13. In this case, the control device 20 calculates ΔW / t based on the weight removed by the noise removing means. The noise removing means is provided in, for example, the control device 20 and the weight sensor 13.

The method for removing noise is not particularly limited, but for example, the weight of the fermentation raw material calculated by the weight sensor 13 when the rotating shaft 3 is rotated can be removed as noise. In this case, the weight value (actual measurement value) of the fermentation raw material during rotation is not used in the calculation of ΔW / t, but the fixed value is used in the calculation of ΔW / t. As the fixed value, for example, the weight value calculated at the time of the immediately preceding rotation stop is used. As a result, noise (particularly, upside) associated with the rotation of the rotating shaft is cut, and the weight value is stabilized, so that ΔW / t can be calculated stably. As another method for removing noise, the minimum weight value calculated during a predetermined time (for example, 5 minutes) is applied to the next predetermined time (for example, 5 minutes) regardless of the rotation of the rotation shaft. There is a way to take over as the weight of).

Next, the installation position of the weight sensor 13 will be described with reference to FIG. FIG. 5 is a diagram showing an example of the installation position of the weight sensor (bottom surface of the main body of the device). As shown in FIG. 5, the weight sensor 13 can be evenly arranged in the circumferential direction on the outer bottom surface of the cylindrical vertical device main body 1a on the circumference. Three weight sensors 13 in FIG. 5A are provided in order to support the load of the device main body 1a and maintain the stability of the device main body 1a. The number of weight sensors to be installed may be four or more when it is desired to improve the stability of the container or when it is desired to improve the accuracy of the calculated weight. For example, in FIG. 5B, four weight sensors 13 are provided. By providing a plurality of weight sensors in this way, the load applied to each weight sensor does not become excessive, so that the weight of the processed material in the container can be accurately calculated.

Example 1
An operation management example (Example 1) in which a short-term index and a long-term index are combined will be described based on the test results of Table 1 and FIGS. 7 to 9.

A fermentation and drying test was conducted for about 2 weeks (October 1st to October 13th) using a component C-40ET (volume 39m ^{3) manufactured by Chubu Ecotech Co., Ltd.} The discharge 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 and 11:00). As will be described later, the input amount and composition of the fermentation raw material were adjusted in consideration of the weight change of the fermenter and the discharge status of the fermented dried product. Table 1 shows the input amounts of sewage sludge and fermentation aids during the test period.

In the short-term control, the inverter frequency of the air supply blower was changed using the exhaust temperature as an index (method (a) described above). The frequency control divides the exhaust temperature into six regions, and the frequency is constant and the exhaust temperature is constant in the region where the exhaust temperature is less than 45 ° C (stage 1) and the region where the exhaust temperature is 65 ° C or higher (stage 6). In the region of 45 ° C. or higher and lower than 65 ° C. (stages 2 to 5), proportional control with different proportionality constants was used (see FIG. 6). In the long-term control, the type and compounding ratio of the fermentation aid were adjusted so that ΔW / t increased using ΔW / t as an index.

7 and 8 show the transition of the exhaust temperature and the weight change of the contents in the container during the test period, and FIG. 9 shows the transition of the inverter frequency and the exhaust temperature of the air supply blower during the same test period. ing.

From FIGS. 7 and 9, it can be confirmed that the inverter frequency of the air supply blower changes following the change in the exhaust temperature. In FIG. 8, the weight W from the raw material input to the discharge of the fermented dried product on the next day from October 1st to 13th is linearly decreased on each day. This means that the fermentation rate is maintained at a substantially constant value from the input of the raw material to the discharge of the fermented dried product on the next day, and it is considered that the above-mentioned short-term control is effectively functioning.

From FIG. 8, the weight of the contents in the container at 18:00 and the weight of the contents in the container at 6 o'clock on the next day were calculated on each day of the test period, and the difference ΔW and the decrease thereof were calculated. The results of calculating the weight velocity ΔW / t are also shown in Table 1. In this case, the calculation span of ΔW / t is 12 hours.

In the first week of the test period, ΔW / t was low, and the water content of the fermented dried product was high and inhomogeneous, so that it was evaluated as poor fermentation. Based on this, the type and compounding ratio of the fermentation aid were changed, but no improvement in ΔW / t was observed. Therefore, from the second week of the test period, a predetermined amount of fermented chicken manure was added as a fermentation aid. Specifically, on October 8th, about 10% by mass of fermented chicken manure was added to the weight of the contents in the container, and from October 9th to 11th, the weight of the sewage sludge to be added was increased. On the other hand, about 10% by mass of fermented chicken manure was added.

As shown in Table 2 and FIG. 8, the weight loss rate ΔW / t (for example, the slope of the straight line X) during the period when the fermented chicken manure was not added was approximately 0.4 to 0.5 kg / min. On the other hand, the weight loss rate ΔW / t (for example, the slope of the straight line Y) during the period in which the fermented chicken manure was added was approximately 0.8 to 1.1 kg / min. It can be seen that the addition of fermented chicken manure promoted fermentation and significantly increased the weight loss rate ΔW / t. In this way, the slope of weight loss, that is, ΔW / t, is an index of the fermentation state depending on the presence or absence of fermented chicken manure, and can be simply compared quantitatively as a difference in numerical values, and ΔW / t is a long-term index. It can be said that it is suitable as.

In this way, while stabilizing fermentation in a short span (span of several minutes) by short-term control, the quality of the fermentation state is judged based on the weight loss rate ΔW / t. For example, when the fermentation state is bad, It is effective to add a fermentation aid to the fermentation raw material (long-term control over a span of several hours to one day). As a result, fermentation and drying can be performed stably and efficiently. As a specific method of long-term control, the weight loss rate ΔW / t in the same time zone is calculated every day, and when the calculated ΔW / t is equal to or less than a predetermined value (for example, 0.5 kg / min or less), the next time. A predetermined amount of fermented chicken manure can be added to the fermented raw material of.

Example 2
An operation management example (Example 2) in which a short-term index and a long-term index are combined will be described based on the test results of period A (November 12 to 15) and period B (February 4 to 7).

For both periods, a component C-40ET (volume 39 m ³ ) manufactured by Chubu Ecotech Co., Ltd. was used. Fermentation raw materials are basically added every day, and after the fermented dried products are discharged, the amount and composition of the fermentation materials are adjusted in consideration of the fermentation situation in the container, and the specified time (between 10:00 and 11:00). Fermentation raw material was put into. Table 2 shows the input amounts of sewage sludge and fermentation aid during both test periods. For both period A and period B, as the short-term control, the air supply amount control using the exhaust temperature used in Example 1 as an index was applied. Further, fermented chicken manure, which was considered to be an effective fermentation aid in Example 1, was added to the sewage sludge by about 5% by mass in period A and about 10% by mass in period B, which is a long-term index of ΔW /. The effect on t was confirmed.

The input amount and composition of the fermentation raw material are shown in Table 2 below. FIG. 10 shows the transition of the weight of the contents in the container in the predetermined time zone (time zone from 18:00 to 6:00 the next day) on the third day in the period A and the period B.

From FIG. 10, both the period A and the period B show a linear weight loss, and the fermentation rate is kept at a substantially constant value. From the above, it is considered that the above short-term control is functioning effectively in both test periods.

From FIG. 10, both the period A and the period B have a weight loss rate ΔW / t (slope of the approximate expression in each figure) of 1.0 kg / min or more in a predetermined time zone, and it is considered that the fermentation state is good. .. Further, since the weight loss rate ΔW / t was larger when the addition amount was 10% by mass than when the addition amount was 5% by mass, it is considered that the fermentation state was further improved by increasing the addition amount of fermented chicken manure. From this, it can be said that the weight loss rate ΔW / t is effective as a long-term index of the effect of the fermentation aid such as fermented chicken manure.

From Example 1 and Example 2, in the fermentation and drying method of the present invention, the amount of air intake is adjusted based on a short-term index, and the amount of fermentation raw material input is adjusted based on a long-term index. It is a fermentation and drying method that complements each other from a micro perspective and a macro perspective. As a result, fermentation and drying of the fermentation raw material can be carried out more stably.

The fermented and dried product obtained by the fermentation and drying method of the present invention can be used, for example, for the production of cement such as a cement raw material and a heat energy source. Furthermore, the fermentation and drying method of the present invention is also a method for producing a fermented and dried product used for producing cement. The method for producing cement of the present invention will be described below. In this production method, the above-mentioned fermented dried product obtained from sewage sludge or the like is used as a cement raw material.

In the method for producing cement of the present invention, the above-mentioned fermentation / drying apparatus and cement manufacturing apparatus are used. This cement manufacturing device is a device involved in the process from the fermented dried product to the firing of the cement clinker. The cement manufacturing apparatus includes, for example, a preheating apparatus for preheating the fermented and dried product obtained by the fermentation and drying method in the above-mentioned fermentation and drying apparatus, a calcining furnace for preheating the preheated fermented and dried product, and a calcined and dried product. It is equipped with a rotary kiln that fires objects and a clinker cooler that cools the cement clinker obtained by firing with the rotary kiln. As the preheating device, a suspension preheater provided with a plurality of preheater cyclones can be used. The calciner is connected to the raw material supply side of the rotary kiln, and the clinker cooler is connected to the clinker discharge side of the rotary kiln.

The fermented dried product is put into a preheating device via a raw material supply port, is sequentially preheated by a plurality of preheater cyclones, and then introduced into a calcining furnace to be calcined. The tentatively fired fermented dried product is introduced into a rotary kiln and fired by a burner. The fired fermented and dried product is discharged from the rotary kiln, cooled by a clinker cooler, and discharged to the outside. This makes it possible to produce a cement clinker using a fermented and dried product as a raw material. The method for producing cement of the present invention is not limited to the above configuration.

The fermented and dried product obtained by the fermentation and drying method of the present invention may be used as a heat energy source in, for example, a plant other than cement production. One example is various plants such as power plants that require a heat source.

The fermentation and drying method of the present invention can more stably ferment and dry the fermentation raw material by using an index suitable for each operation control. Therefore, for example, an apparatus for fermenting and drying sewage sludge generated in a sewage treatment facility. Can be suitably used as.

1 Fermentation and drying device 1a Equipment body 2 Container 2a Input port 2b Outlet 2c Exhaust port 3 Rotating shaft 4 Stirring blade 4a Vent hole 5 Machine room 6 Air supply blower 7 Heater 8 Hydraulic cylinder 9 Exhaust means 10 Exhaust pipe 11 Exhaust blower 12 Deodorization Device 13 Weight sensor 14 Temperature sensor 15 Temperature sensor 16 Flow sensor 17 Oxygen sensor 18 Pressure sensor 19 Control panel 20 Control device

Claims (8)

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 apparatus provided with means.
In the fermentation / drying apparatus, the outside air is introduced into the container by the air supply means, and the inside air is exhausted from the container by the exhaust means, and the fermentation raw material charged into the container is introduced by the stirring blade. It is a device that ferments and dries with stirring and discharges the fermented dried product.
The fermentation / drying apparatus has a weight sensor that directly or indirectly calculates the weight of the fermentation raw material in the container.
The fermentation / drying method calculates at least one first fermentation index of the amount of heat of fermentation in the fermentation / drying apparatus, the temperature of the inside air discharged by the exhaust means, and the rate of generation of carbon dioxide in the fermentation / drying apparatus. The calculation step, the first adjustment step of adjusting the amount of outside air introduced into the container based on the first fermentation index calculated in the first calculation step, and the fermentation calculated by the weight sensor. Based on the weight of the raw material, the second calculation step of calculating the weight loss rate, which is the weight loss per unit time, as the second fermentation index, and the fermentation based on the weight loss rate calculated in the second calculation step. A method for fermenting and drying, which comprises a second adjusting step for adjusting at least one of the input amount of the raw material, the composition of the fermentation raw material, and the discharge amount of the fermented dried product. The first calculation step is a step of calculating the temperature of the inside air as the first fermentation index, and the first adjustment step is a temperature range to which the temperature of the inside air belongs among a plurality of divided temperature ranges. The fermentation and drying method according to claim 1, wherein the amount of the outside air is adjusted accordingly. The first calculation step is a step of calculating the fermentation heat amount and the temperature of the inside air as the first fermentation index at predetermined time intervals, and the first adjustment step is a step of calculating the fermentation heat amount and the inside air at an arbitrary calculation. When the temperature increases with respect to both the heat of fermentation calculated last time and the temperature of the inside air, the amount of the outside air is increased, and the heat of fermentation and the temperature of the inside air at an arbitrary calculation are calculated at the previous time. The method for fermenting and drying according to claim 1, wherein the amount of the outside air is reduced when both the amount of heat of fermentation and the temperature of the inside air are reduced. The exhaust means has a wet deodorizing device that performs a treatment related to the internal air, and a concentration sensor for acquiring information on the concentration of carbon dioxide contained in the internal air is provided in an exhaust path on the downstream side of the wet deodorizing device. Has been
The first calculation step according to claim 1, wherein the first calculation step calculates the carbon dioxide generation rate as the first fermentation index based on the information related to the carbon dioxide concentration acquired by the concentration sensor. Fermentation and drying method. The fermentation / drying method is a method in which a cycle of adding the fermentation raw material to the fermentation / drying apparatus and taking out a part of the fermentation / drying product once a day is carried out for two days or more.
When the reduced weight rate in an arbitrary time zone calculated in the second calculation step increases with respect to the reduced weight rate in the same time zone on the previous day, the input amount of the fermentation raw material or the fermentation drying Any one of claims 1 to 4, characterized in that the amount of the fermentation raw material input is reduced or the amount of the fermentation aid added is increased when the amount of the substance discharged is increased and decreased. The fermentation and drying method according to the item. The fermentation drying method according to any one of claims 1 to 5, wherein the fermentation raw material contains sewage sludge. A method for producing cement, which comprises producing cement from a fermented and dried product obtained by the fermentation and drying method according to any one of claims 1 to 6. A method for using a fermented dried product, which uses the fermented dried product obtained by the fermented dried product according to any one of claims 1 to 6 as a heat energy source.

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