JP2021159803A - Fermentation-drying apparatus, cement production system, fermentation-drying method, method for producing cement clinker, and method for using fermentation-dried product - Google Patents

Abstract

To more stably produce a fermentation-dried product.SOLUTION: A fermentation-drying apparatus has: a container which houses a fermentation raw material including sewage sludge, and performs fermentation-drying treatment while agitating the fermentation raw material; air feeding means for feeding air into the container; an air feeding information acquiring part which acquires information regarding the temperature of gas fed by the air feeding means and an air feeding amount; exhaust means for performing exhaustion from the container; an exhaust information acquiring part which acquires information regarding air exhausted by the exhaust means and an exhaust amount; and a control part which controls the air feeding means and the exhaust means, in which the control part calculates fermentation heat quantity from the information acquired in the air feeding information acquiring part and the exhaust information acquiring part, and controls the air feeding means on the basis of the fermentation heat quantity and exhaust temperature.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a fermentation and drying apparatus, a cement production system, a fermentation and drying method, a method for producing cement clinker, and a method for using a fermented and dried product.

Patent Document 1 discloses a vertical fermentation treatment apparatus for fermenting sewage sludge.

Japanese Unexamined Patent Publication No. 2015-013263

The present disclosure provides a technique capable of more stably producing a fermented dried product.

In order to achieve the above object, the fermentation / drying apparatus according to one embodiment of the present disclosure accommodates a fermentation raw material containing sewage sludge, and sends the fermentation raw material into a container for performing fermentation drying treatment while stirring the fermentation raw material and into the container. An air supply means for performing air, an air supply information acquisition unit for acquiring information related to the air supply temperature and the air supply amount of the gas supplied by the air supply means, and an exhaust means for exhausting from the inside of the container. The control unit includes an exhaust information acquisition unit that acquires information on the exhaust temperature and the exhaust amount of the gas exhausted by the exhaust means, and a control unit that controls the air supply means and the exhaust means. The amount of heat of fermentation is calculated from the information acquired by the air supply information acquisition unit and the exhaust information acquisition unit, and the air supply means is controlled based on the heat of fermentation and the exhaust temperature.

Further, the fermentation / drying method according to one embodiment of the present disclosure is a fermentation / drying method in a fermentation / drying apparatus, in which a fermentation raw material containing sewage sludge is stored in a container, and the fermentation raw material is stirred in the container while being stirred. Performing the fermentation and drying treatment, supplying air into the container when performing the fermentation and drying treatment, exhausting from the inside of the container when performing the fermentation and drying treatment, and supplying the air. Acquiring information on the air supply temperature and the air supply amount of the gas to be exhausted, acquiring information on the exhaust temperature and the exhaust amount of the exhausted gas, and relating to the air supply temperature and the air supply amount. Includes calculating the heat of fermentation based on the information and the information on the exhaust temperature and the exhaust amount, and controlling the air supply into the container based on the heat of fermentation and the exhaust temperature. ..

According to the above-mentioned fermentation / drying apparatus and fermentation / drying method, information on the air supply temperature and the amount of air supplied to the container of the fermentation / drying apparatus and the gas exhausted into the container of the fermentation / drying apparatus. The heat of fermentation is calculated based on the information on the exhaust temperature and the exhaust amount, and the air supply into the container is controlled based on the heat of fermentation and the exhaust temperature. Therefore, the fermentation status in the container can be controlled more accurately, and the fermented and dried product can be produced more stably.

The control unit increases the amount of air supplied by the air supply means when both the amount of heat of fermentation and the temperature of the exhaust are increasing, and when both the amount of heat of fermentation and the exhaust temperature are decreasing, the control unit increases the amount of air supplied by the air supply means. The mode can be such that the amount of air supplied by the air supply means is reduced.

As described above, when both the amount of heat of fermentation and the exhaust temperature are increasing, the amount of air supplied by the air supply means is increased, and when both the amount of heat of fermentation and the exhaust temperature are decreasing, the amount of air supplied by the air supply means is increased. When the configuration is such that the amount is reduced, it is possible to appropriately grasp the situation in which the fermentation situation is changing and adjust the situation in the container according to the amount of air supplied. Therefore, the fermented and dried product can be produced more stably.

The control unit may be in a mode of calculating the amount of heat of fermentation based on the difference between the amount of heat of exhaust gas related to exhaust gas and the amount of heat of air supply related to air supply.

As described above, by calculating the amount of heat of fermentation based on the difference between the amount of heat of exhaust gas related to exhaust gas and the amount of heat of air supply related to air supply, it is possible to more accurately grasp the amount of heat of fermentation associated with fermentation in the container. It is possible to manage the fermentation status more accurately based on this information.

The cement manufacturing system according to one embodiment of the present disclosure includes the above-mentioned fermentation and drying apparatus, and a cement manufacturing apparatus that uses a fermented and dried product obtained by the fermentation and drying treatment in the fermentation and drying apparatus.

By producing cement in a cement manufacturing apparatus using the fermented and dried product obtained by the above fermentation and drying apparatus, the fermented and dried product can be more stably supplied to cement production.

The method for producing cement clinker according to one embodiment of the present disclosure is to produce cement clinker using the fermented dried product obtained by the above method as a raw material.

By producing cement clinker using the fermented dried product obtained by the above method as a raw material, cement clinker can be produced using the fermented dried product obtained from sewage sludge as a raw material, so that the waste intensity can be increased. be able to.

In the method of using the fermented dried product according to one embodiment of the present disclosure, the fermented dried product obtained by the above method is used as a heat energy source.

When the fermented dried product obtained by the above method is used as a heat energy source, the fermented dried product can be converted into heat energy and used, so that the use of fossil fuel can be reduced.

According to the present disclosure, there is provided a technique capable of producing a fermented dried product used for producing cement more stably and in a short period of time.

FIG. 1 is a schematic configuration diagram of a production system for producing a fermented dried product according to an embodiment of the present disclosure. FIG. 2 is a schematic configuration diagram of the fermenter. FIG. 3 is a diagram showing a method of controlling air supply in the fermenter. FIG. 4 is a schematic configuration diagram of a cement clinker manufacturing apparatus. FIG. 5 is a diagram showing the results of recording changes in the amount of heat of fermentation and the exhaust temperature according to the examples. FIG. 6 is a diagram showing a result of recording the frequency control content according to the embodiment. FIG. 7 is a diagram showing an air supply control method for a fermenter according to a comparative example. FIG. 8 is a diagram showing the results of recording changes in the amount of heat of fermentation and the exhaust temperature according to the comparative example. FIG. 9 is a diagram showing the results of recording the frequency control contents according to the comparative example.

Hereinafter, embodiments for carrying out the present disclosure will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

[Manufacturing system for fermented dried products]
FIG. 1 is a schematic configuration diagram of a production system for producing a fermented dried product according to an embodiment of the present disclosure. As shown in FIG. 1, the manufacturing system 1 includes a fermenter 2, an air heater 4, an air blower 5, a dust removal tower 6, an exhaust fan 7, a cleaning and deodorizing tower 8, and a control unit 9. What is produced in the production system 1 is a fermented dried product (dried sludge) obtained by fermenting and drying sewage sludge. In addition, the exhaust gas generated by the fermentation of sewage sludge is subjected to a predetermined treatment.

The fermenter 2 has a function of adding sewage sludge and performing a fermentation treatment (fermentation drying treatment). In the fermenter 2, aerobic treatment with aerobic microorganisms is performed. In addition to sewage sludge, raw materials that contribute to fermentation are put into the fermentation tank 2. Further, the fermented dried product (dried sludge) after fermentation is discharged from the fermentation tank 2, and the gas generated by the fermentation is discharged via the line L1.

The air supply heater 4 has a function of heating the gas introduced into the line L3 and supplying it to the line L2. The temperature of the gas charged into the fermenter 2 is, for example, about 50 ° C. to 80 ° C. The air supply heater 4 has a function of heating the gas to be introduced into the line L2 so as to be within a predetermined temperature range. A heat exchange means (not shown) may be provided upstream of the air supply heater 4, for example, by using the heat of the exhaust gas of the line L1 to heat the outside air introduced into the container from the air supply fan. The form of the heat exchange means is not particularly limited, and the exhaust gas from the line L1 is cooled by the heat exchange. On the other hand, the heated air is introduced into the fermenter 2 via the line L2.

The air supply blower 5 has a function of supplying gas to the line L2. A motor M1 is connected to the air supply blower 5, and air from the outside is introduced into the line L3 and supplied to the line L2 by the air supply blower 5 operated by the operation of the motor M1.

The dust removal tower 6, the exhaust fan 7, and the cleaning and deodorizing tower 8 are provided on the line L1 for discharging the exhaust gas, and have a function of deodorizing the exhaust gas.

The dust removal tower 6 has a function of introducing the exhaust gas flowing through the line L1 and removing the dust contained in the exhaust gas. Equipment such as a scrubber is used as the dust removal tower. The gas from which the dust has been removed is sent to the cleaning / deodorizing tower 8 via the exhaust fan 7.

The exhaust fan 7 has a function of moving the exhaust gas on the line L1. A motor M2 is connected to the exhaust fan 7, and the exhaust gas is moved to the downstream side by driving the exhaust fan 7 by the operation of the motor M2. As the fan, a fan whose rotation speed can be controlled by the inverter frequency can be used.

The washing and deodorizing tower 8 has a function of removing trace odor components such as ammonia contained in the exhaust gas from the fermenter. As an example, the cleaning and deodorizing tower 8 is a wet cleaning tower, and can be an acid cleaning tower that uses sulfuric acid as an absorbing liquid. The cleaning and deodorizing tower 8 is not limited to the acid cleaning and deodorizing tower, and various configurations can be adopted as long as it is configured to perform cleaning and deodorizing such as alkaline cleaning and deodorizing and alkaline / hyposalt cleaning and deodorizing. Cleaning and deodorizing can be appropriately selected according to the gas to be treated. For example, an acid scrubber is used when ammonia is the target of deodorization. Further, depending on the type and number of gases contained in the exhaust gas, a plurality of cleaning and deodorizing towers can be connected in series. If hydrogen sulfide may be generated, an alkali / hypochlorous acid washing / deodorizing tower that combines sodium hydroxide and sodium hypochlorite may be further provided.

The wet deodorizing device is not limited to the above configuration. For example, it may include an adsorption tower that is filled with activated carbon and removes odorous components that cannot be sufficiently removed by the action of the above liquid by the adsorption action of the activated carbon. The adsorption tower may be installed at the last stage of the plurality of processing devices.

The control unit 9 has a function of controlling each of the above units. The control unit 9 receives output signals from sensors and the like provided in various parts of the manufacturing system 1 and each of the above-mentioned parts, and transmits an input signal for controlling the operation to each of the above-mentioned parts. The control unit 9 acquires an air supply information acquisition unit that acquires information on the temperature and the amount of air supplied by the air supply means, and an information on the temperature and the amount of exhaust gas exhausted by the exhaust means. It has a function as an exhaust information acquisition unit.

As shown in FIG. 1, in the manufacturing system 1, sensors are provided at various places. For example, a weigh scale W for measuring the weight of the fermenter 2 is provided. A thermometer T4 for measuring the temperature of the gas discharged from the fermenter 2 is provided on the line L1. Further, a thermometer T5 for measuring the temperature of the air introduced into the fermenter 2 is provided between the air supply heater 4 on the line L2 and the inlet to the fermenter 2. Further, a flow meter F, a thermometer T6, and a pressure gauge P2 are provided on the line L3 for introducing air from the outside. A frequency meter Hz1 is provided on the motor M1 connected to the air supply blower 5. The control unit 9 can acquire the measurement results of these sensors as output signals, change the control contents based on the measurement results, and input the control contents.

[Fermenter]
Next, the fermenter 2 will be described. FIG. 2 is a schematic configuration diagram of the fermenter 2. The fermenter 2 is a closed vertical fermenter. The fermenter 2 has a container 21 extending in the vertical direction (direction A in the drawing) with respect to the installation surface. Above the container 21, a charging port 22 for charging sewage sludge, auxiliary raw materials, and the like is provided. Further, below the container 21, a discharge port 23 for discharging the fermented and dried product after the treatment in the container 21 is provided. Both the inlet 22 and the outlet 23 are provided with a lid-like member (not shown) that can be opened / closed or detached, such as a lid. By attaching the lid-shaped member to the inlet 22 and the outlet 23, the container 21 in the fermenter 2 can be sealed. In this way, the fermentation tank 2 enables aerobic fermentation in a closed system. From the viewpoint of further improving the drying efficiency of the contents by the aerobic fermentation heat, the fermenter 2 may have a heat insulating structure by, for example, arranging a heat insulating material on the outer peripheral surface of the container 21.

It is also preferable that the fermenter 2 is provided with a stirring device 24 for mixing the raw materials in the fermenter. As an example, the stirring equipment 24 includes, for example, a stirring blade 24a provided inside the container 21, a rotating shaft 24b connected to the stirring blade 24a, and a rotation driving device (not shown) provided outside the container 21. I have. The stirring blade 24a is connected to a rotation driving device provided outside the container 21 via a rotating shaft 24b, and rotates in a certain direction using a hydraulic cylinder as a driving source. The stirring blades 24a may be provided in multiple stages at predetermined intervals from the lower part to the upper part of the rotating shaft 24b. By further providing the stirring equipment 24, it is possible to suppress an excessive consolidation state of the contents such as sewage sludge, and it is possible to improve the aerobic fermentation efficiency.

Further, the fermenter 2 includes an air supply means 25 for supplying an oxygen-containing gas such as air into the fermenter 2, and an exhaust means 26 capable of exhausting the gas in the container 21 to the outside of the container 21. The oxygen-containing gas F can be, for example, air. As an example, the oxygen-containing gas F is sent from the air supply means 25 provided outside the container 21 to the lower side in the vertical direction of the stirring blade 24a via the hollow rotating shaft 24b and the ventilation hole of the stirring blade 24a. It may be able to supply. In the example shown in FIG. 2, a plurality of gas flow holes through which the oxygen-containing gas F can flow are provided on the lower side of the stirring blade 24a provided at the lowermost position in the vertical direction. In this case, the oxygen-containing gas F can be evenly supplied to the container 21 while stirring the contents by the stirring blade 24a. The oxygen-containing gas F existing in the container 21 and the gas generated by aerobic fermentation are exhausted to the line L1 (see FIG. 1) as exhaust gas via the exhaust means 26 provided above the container 21. ..

From the viewpoint of increasing the contact efficiency between the oxygen-containing gas and the contents and increasing the aerobic fermentation efficiency of the sewage sludge in the container 21, the oxygen-containing gas F is supplied from the lower side in the vertical direction of the container 21 and contains oxygen. The exhaust gas containing the gas F can be configured to be exhausted from the upper side of the container 21 in the vertical direction.

The fermentation raw material containing sewage sludge is continuously or intermittently charged into the container 21 in the fermenter 2 from the inlet 22. The fermentation raw material is aerobically fermented in the fermenter 2 and then discharged as a fermented dried product from the discharge port 23.

In the fermenter 2 described above, the fermentation raw material is charged into the container 21 from the input port 22, the processed product is fermented in the container, and then the fermented dried product is taken out from the discharge port 23 at the bottom of the container 21. In the fermenter 2, the air supply means 25 introduces the outside air from the ventilation holes of the lowermost stirring blade 24a with a predetermined amount of air, and exhausts the outside air from the exhaust means 26. In this state, each stirring blade 24a is rotated at a low speed, the fermentation raw material is aerated and stirred, and aerobic fermentation is performed to carry out fermentation. In addition, the contents are dried at the same time by the heat of fermentation generated by aerobic fermentation. The air discharged from the exhaust means 26 is a gas such as carbon dioxide or ammonia generated in the process of fermentation with respect to the gas that is introduced into the container through the ventilation holes and flows upward while passing through the processed product. It contains water vapor.

An example of the operation procedure of the fermenter 2 is as follows. First, a fermentation raw material such as sewage sludge is charged into the fermentation tank 2 from the inlet 22 leaving a space of 10 to 30% with respect to the internal volume of the container 21. By adding the fermentation raw material while leaving the above-mentioned space, the fermentation raw material is sufficiently and uniformly agitated and aerated. Therefore, fermentation and drying in the container 21 can be efficiently performed. As an example, the fermented raw material is added daily. That is, the fermentation raw material can be added a plurality of times (at regular intervals) at predetermined intervals. Further, the fermentation and drying of the fermentation raw material are continued for a predetermined residence period (about 3 to 20 days) in the fermenter 2, and a predetermined amount of the fermented dried product is taken out from the discharge port 23 at regular intervals (for example, every day). .. The fermentation raw material is added after the fermented dried product is taken out from the discharge port 23. In this way, the fermentation process is continuously performed while repeating a part of the sewage sludge fermentation raw material and a part of the fermented product in a fixed time cycle. The fermented and dried product obtained by the above procedure is a powdery or granular solid material, and is partially agglomerated.

[Fermentation control method in fermenter 2]
In the fermenter 2, as fermentation indexes, the "heat of fermentation" and the "heat of fermentation" per predetermined time calculated based on the aeration amount (air intake amount, exhaust amount), intake air temperature, intake air humidity, exhaust temperature, and exhaust humidity. "Exhaust temperature" is used as a fermentation index. Further, the fermentation tank 2 is controlled by the control unit 9 based on these fermentation indexes. This point will be described.

Regarding the control of the fermenter 2, specifically, the aeration control is performed by comparing the fermentation heat amount H (feed / exhaust enthalpy difference) and the exhaust temperature T at an arbitrary time with the fermentation heat amount H and the exhaust temperature T at the time of the previous measurement. I do.

The amount of heat for fermentation is obtained from the difference between the amount of heat of the exhaust gas discharged from the fermentation tank 2 and the amount of heat of the air supplied to the fermentation tank 2. That is, the amount of heat of fermentation satisfies the relationship shown in the following mathematical formula (1).
Fermentation heat quantity (kJ / min) = Exhaust heat quantity (kJ / min) -Air supply heat quantity (kJ / min) ... (1)

The above exhaust heat amount can be calculated based on the following mathematical formula (2).
q = fi / v ... (2)
In the formula (2), f is the displacement (m ³ / min), i is the specific enthalpy of the exhaust (kJ / kg), and v is the specific volume of the exhaust (m ³ / kg).

The displacement f (m ³ / min) may be measured directly with an exhaust flow meter. Although the exhaust flow meter is not shown in FIG. 1, as an example, a flow meter may be inserted into the line L1 for measurement.

For the specific enthalpy i (kJ / kg), the absolute humidity of the line L1 is calculated from the temperature T4 of the exhaust gas passing through the line L1, the pressure (not shown), and the relative humidity (not shown), and this and the exhaust temperature. Calculated using a predetermined approximation formula showing the relationship with T4. This approximation can be created, for example, by plotting a data set of steam tables for temperature and steam heat.

For the specific volume v (m ³ / kg), the absolute humidity of the line L1 is calculated from the temperature T4, pressure (not shown), and relative humidity (not shown) of the exhaust gas passing through the line L1, and this and the exhaust gas. Calculated based on the temperature T4.

Further, the amount of heat supplied is the same as that of the formula (2) used for calculating the amount of heat exhausted, but the amount of air supplied is used as f, the specific enthalpy of air supply (kJ / kg) is used as i, and v is defined as v. The amount of heat supplied can be calculated by using the specific volume of air supplied (m ^{3 / kg).}

Feed amount ^f (m 3 / min), the flow rate of the line L3 of the ^(m 3 / min) was measured, obtained by temperature compensation by T6 and fermenter air temperature T5. Further, the flow rate of the line L3 may be measured directly by inserting a flow meter into the line L3. Alternatively, the flow rate calculated from the wind speed value of the line L3 and the inner diameter of the pipe may be used. Further, when there is a linear relationship between the inverter frequency of the fan used in the air supply means 25 and the air supply amount, it can be calculated based on this inverter frequency.

For the specific enthalpy i (kJ / kg), the absolute humidity of the line L3 is calculated from the temperature T6, the pressure P2, and the relative humidity (not shown) of the exhaust gas passing through the line L3, and this and the fermenter air supply temperature T5. It is calculated using a predetermined approximation formula showing the relationship with. This approximation can be created, for example, by plotting a data set of steam tables for temperature and steam heat.

For the specific volume v (m ³ / kg), the absolute humidity of the line L3 is calculated from the temperature T6, pressure P2, and relative humidity (not shown) of the exhaust gas passing through the line L3, and this and the insufflation temperature of the fermenter are calculated. Calculated according to T5.

As described above, various parameters related to exhaust and air supply are used to calculate the exhaust heat amount and the air supply heat amount. To calculate these parameters, the outside air temperature (air supply temperature), exhaust temperature, air supply relative humidity, exhaust relative humidity, and the inverter frequency of the fan of the air supply means 25 are acquired. Then, based on this information, it may be necessary to calculate the amount of air supply, the absolute humidity, the water vapor pressure in the moist air, the unit volume of the moist air, and the molecular weight of the moist air. Also, regarding the amount of exhaust heat, when it is necessary to calculate the amount of exhaust, absolute humidity, water vapor pressure in moist air, unit volume of moist air, molecular weight of moist air, number of moles of moist air, and mole fraction of dry air. There is.

Of these, the absolute humidity is calculated using the water vapor pressure of moist air. The number of moles of moist air is calculated from the displacement and the unit volume of moist air. The mole fraction of dry air is calculated using absolute humidity. The moist air unit volume is calculated using the exhaust temperature. The molecular weight of moist air is calculated from the mole fraction of dry air and the mole fraction of water vapor. The water vapor pressure in moist air is calculated using the relative humidity and the saturated water vapor pressure of the dry-bulb temperature. Calculation of these various parameters can be performed by a known method.

If the line L1 is not provided with a relative hygrometer, the relative humidity of the line L1 may be fixed at 100%. If the line L2 is not provided with a relative hygrometer, the relative humidity of the sucked air (outside air) by the air supply blower is fixed at 70%, and the absolute humidity is calculated based on the outside air temperature. The relative humidity of the fermenter air supply may be calculated using the temperature T6 and the pressure P2. The inverter frequency of the air supply blower can be obtained from the operation content of the air supply means 25. Based on these numerical values, the above-mentioned various parameters can be calculated.

By controlling the pressure in the fermenter 2 to a slight negative pressure near the atmospheric pressure, the amount of leaked air (inflow or outflow) at the outside air seal portion of the raw material input port and the product discharge port can be ignored. In this case, after measuring the amount of air supplied to the fermenter 2 (the amount of gas flowing through the line L3 (L2)) using the method described in the above-mentioned method for calculating the air supply flow rate, the lines L3 and L1 Assuming that the dry air amount is constant and the relative humidity of the line L1 is 100%, the exhaust amount may be calculated based on the dry air flow rate of the line L3 and the exhaust temperature of the line L1. By this method, the exhaust amount can be calculated without providing the exhaust flow meter on the line L1.

The "exhaust temperature" can be measured by using, for example, a thermometer T5 provided on the line L1.

Based on the above method, the control unit 9 measures the temperature, relative humidity and flow rate of the air supply introduced into the fermenter 2 and the temperature, relative humidity and flow rate of the exhaust from the fermenter 2 at predetermined time intervals. Then, the heat supply heat amount and the exhaust heat amount are calculated by the above-mentioned method, and the fermentation heat amount H is calculated from the difference between the two. Then, the control unit 9 controls the air flow amount (air supply amount) to the fermenter 2 based on the calculation result and the fermenter exhaust temperature T4. FIG. 3 is a flow chart for explaining the contents of control by the control unit 9.

First, the control unit 9 calculates the amount of heat of fermentation H (step S01) and acquires the exhaust temperature T (step S02). These processes may be performed simultaneously or individually. Based on these results, the control unit 9 determines whether both the fermentation heat amount H and the exhaust temperature T are increased as compared with the previous calculation result (S03). When both the fermentation heat amount H and the exhaust temperature T are increased as compared with the previous calculation result (S03-YES), the control unit 9 increases the air flow amount (air supply amount) to the fermentation tank 2 (S04). ). As the amount of increase in the air flow amount (air supply amount), for example, it is conceivable to increase the inverter frequency of the fan in the air supply means 25 by 0.2 Hz. However, this amount of increase can be appropriately changed depending on the capacity of the fermenter 2 and the function of the air supply means 25.

On the other hand, when either one of the fermentation heat quantity H and the exhaust temperature T is not increased as compared with the previous calculation result (S03-NO), the control unit 9 calculates both the fermentation heat quantity H and the exhaust temperature T in the previous calculation. It is determined whether the decrease is compared with the result (S05). When both the fermentation heat amount H and the exhaust temperature T are reduced as compared with the previous calculation result (S05-YES), the control unit 9 reduces the air flow amount (air supply amount) to the fermentation tank 2 (S06). ). As the amount of decrease in the air flow amount (air supply amount), for example, it is conceivable to reduce the inverter frequency of the fan in the air supply means 25 by 0.2 Hz. However, this amount of reduction can be appropriately changed depending on the capacity of the fermenter 2 and the function of the air supply means 25. When either one of the fermentation heat amount H and the exhaust temperature T is not decreased as compared with the previous calculation result (S03-NO), the control unit 9 maintains (stays) the air flow amount (S07). The control of the aeration amount (air supply amount) based on this determination is continued until the operation of the fermenter 2 is completed (S08-YES).

In the series of operations (steps S01 to S08) in the control unit 9, for example, the control standby time is set to 3 minutes, the measurement results of various measuring instruments such as a thermometer are acquired every second, and the acquired results are 3 The amount of heat of fermentation H and the exhaust temperature T can be calculated by averaging every minute, and the amount of air flow (exhaust amount) can be controlled every 3 minutes.

As described above, in the present embodiment, by controlling the fermentation state by combining the fermentation heat amount H and the exhaust temperature T, it is possible to maintain a good fermentation state without causing insufficient ventilation or excessive ventilation.

When a plurality of fermenters 2 are provided in the manufacturing system 1, various sensors are individually installed for each fermenter and the above control is performed to more appropriately manage each fermenter. Can be done. Further, when the exhaust treatment equipment or the dust removal equipment is installed connected to the fermenter 2, the washing and deodorizing tower 8 can be shared by a plurality of fermenters 2, but each fermenter and the exhaust line can be shared. By individually installing various sensors such as a thermometer, it is possible to individually control the air supply / exhaust to each fermenter 2.

[Fermentation raw material]
As the fermentation raw material used for producing the fermented dried product in the fermenter 2, in addition to the sewage sludge which is the main raw material, an auxiliary raw material or the like is used. Hereinafter, details of each raw material and its mixing ratio and the like will be described.

[Sewage sludge]
The sewage sludge is a sludge-like or paste-like substance containing organic substances, inorganic substances and water, which is obtained by dehydrating excess sludge generated in the process of activated sludge treatment of sewage with a dehydrator such as a filter press. As the sewage sludge, this may be used as it is, or a self-fermented product of sewage sludge such as digestive sludge may be used. The water content of the sewage sludge is not particularly limited, but is, for example, about 70% to 90%.

[Auxiliary raw material]
The fermentation raw material may contain auxiliary raw materials in addition to sewage sludge. The auxiliary raw material is a material for promoting stable aerobic fermentation of sewage sludge when the sewage sludge fermentation raw material is subjected to fermentation by containing it together with sewage sludge. Specifically, the auxiliary raw material reduces the water content of the sewage sludge, enhances the air permeability of the sewage sludge fermentation raw material containing the sewage sludge and the auxiliary raw material, and serves as a nutrient source for microorganisms that contribute to aerobic fermentation. It is used to supply easily degradable organic components and to supply aerobic microorganisms for efficiently advancing aerobic fermentation.

The shape of the auxiliary raw material used is not particularly limited, and may be, for example, a solid, granular, powdery, paste-like, fluid-like, or liquid-like shape. The total content of the auxiliary raw material can be appropriately adjusted according to the physical properties and purpose of the auxiliary raw material used, but the total weight part of the auxiliary raw material with respect to 100 parts by weight of the sewage sludge is preferably 5 parts by weight or more and 100 parts by weight or less. It can be preferably 5 parts by weight or more and 50 parts by weight or less, and more preferably 5 parts by weight or more and 40 parts by weight or less. At this time, the weight of the reference sewage sludge is the weight in the water-containing state.

Ventilation aids and nutritional aids that can be used as examples of auxiliary materials will be described.

[Ventilation aid]
The fermentation raw material may contain a ventilation aid for the purpose of reducing the water content and improving the air permeability. Examples of the aeration aid include organic aeration aids such as rice straw, fir tree, sawdust, bark, vegetation or dried or crushed products thereof, and inorganic aeration aids such as perlite, zeolite, diatomaceous earth and coal ash. Materials and the like are used. By including the aeration auxiliary material, it is possible to secure the aerobic fermentation of the sewage sludge while suppressing the excessive consolidation state, which is advantageous in that the aerobic fermentation of the sewage sludge can proceed stably and effectively. be.

The shape of the ventilation auxiliary material is not particularly limited, and may be, for example, a solid, granular, powdery, paste-like, fluid-like, or liquid-like shape. The content of the ventilation auxiliary material can be appropriately adjusted according to the physical properties and purpose of the auxiliary raw material used, but the total weight part of the ventilation auxiliary material with respect to 100 parts by weight of the sewage sludge is preferably 5 parts by weight or more and 80 parts by weight or less. More preferably, it can be 5 parts by weight or more and 50 parts by weight or less. At this time, the weight of the reference sewage sludge is the weight in the water-containing state.

Among the above-mentioned ventilation aids, fly ash can be included as an example. Fly ash is a type of coal ash produced by burning coal. For example, coal ash produced when pulverized coal is burned at a coal-fired power plant and is recovered by an electrostatic collector or the like. Be done. Fly ash, its bulk density is preferably 0.2 g / cm ³ or more 1.5 g / cm ³ or less, the Blaine specific surface area of preferably those 1000 cm ² / g or more 20000cm of ² / g or less, silica, alumina, Includes calcium oxide (CaO), magnesium oxide and the like.

By using fly ash for fermentation treatment of sewage sludge, aerobic fermentation can proceed stably from an initial stage. The reason for this is not clear, but it is considered that the fly ash itself has high dispersibility due to the relatively fine particles. Further, it is considered that the CaO component contained in the fly ash easily aggregates the particles of the sewage sludge to form flocs and easily lowers the density of the sewage sludge fermentation raw material.

[Nutrition aid]
From the viewpoint of promoting aerobic fermentation of sewage sludge, the fermentation raw material may further contain a nutritional auxiliary material. Nutrient aids are used to supply easily degradable organic matter, which is a nutrient source for microorganisms that contribute to aerobic fermentation, and to supply aerobic microorganisms that promote aerobic fermentation efficiently. It is an auxiliary material to be obtained. Examples of nutritional aids include food processing residues such as food sludge, sake lees and shochu lees, waste white clay, paper sludge, waste cooking oil, waste solid fuel (RDF), meat bone powder, food waste, urine, livestock manure, compost, etc. Activated sludge, scum, etc. can be mentioned. These can be used alone or in combination.

Among the above-mentioned nutritional aids, meat-and-bone meal can be adopted because it further promotes aerobic fermentation and increases the temperature-increasing effect of fermentation. Meat-and-bone meal is, for example, obtained by removing meat from beef, pork, and chicken and then heat-treating it together with internal organs, offal, and the like. For example, it is a dry pulverized product crushed into powder. The meat-and-bone meal powder can improve the mixing efficiency with other fermentation raw materials such as sewage sludge. The content of the nutritional auxiliary material is preferably 5 parts by weight or more and 100 parts by weight or less, and more preferably 5 parts by weight or more and 50 parts by weight or less with respect to 100 parts by weight of sewage sludge. At this time, the weight of the reference sewage sludge is the weight in the water-containing state.

[Mixing of fermentation raw materials and water content]
The fermentation raw material can be, for example, a mixture of sewage sludge and an auxiliary raw material. As an example, a mixture of fermentation raw materials may be prepared by premixing sewage sludge and auxiliary raw materials before supplying them to a device for fermentation such as a fermentation tank 2. Further, the fermentation raw material may be prepared indoors or outdoors as a deposit in which the other is deposited on one of the sewage sludge and the auxiliary raw material. Further, one of the sewage sludge and the auxiliary raw material may be supplied to a container for fermentation, and then the other may be supplied into the container to form a deposit in which each raw material is alternately deposited in the container. In this case, fermentation may be started from the state of sediment, or fermentation may be started after the sediment is mixed in a container and mixed.

From the viewpoint of ensuring a sufficient amount of water for the stable progress of aerobic fermentation from the initial stage of fermentation, the water content of the fermentation raw material can be 30% or more and 70% or less. Further, when the water content is 40% or more and 60% or less, aerobic fermentation can proceed more stably. The water content can be measured based on the difference in weight before and after drying when dried at a heating temperature of 100 ° C. to 120 ° C. using, for example, a commercially available infrared moisture meter or halogen moisture meter. Alternatively, the measurement can be performed according to JIS A 1203 “Soil water content ratio test method”. The water content of the fermentation raw material can be appropriately adjusted, for example, by selecting the raw material so as to have a desired water content, or by adding water to the raw material or the fermentation raw material.

The above-mentioned fermentation raw material can be subjected to aerobic fermentation treatment by supplying the above-mentioned fermentation raw material in the state of a deposit or a mixture to the container 21 of the fermentation tank 2 as described above.

[Use of fermented dried products]
As the fermentation of the fermentation raw material progresses, the water content of the fermentation raw material gradually decreases. As a result, in the state of the fermented and dried product, the water content is about 10% to 40%, preferably about 15% to 35%. The fermented dried product can be used for cement production applications such as fertilizers, soil conditioners, green farm materials such as garden soil, solid fuels, cement clinker raw materials, and heat energy sources. Further, as the heat energy source, for example, it may be used in a plant other than cement manufacturing, and examples thereof include various plants that require a heat source such as a power plant.

In the following, as an example, a case where a fermented dried product is used as a raw material for cement clinker will be described. The above-mentioned manufacturing system 1 and the cement clinker manufacturing apparatus 100 shown in FIG. 4 constitute a cement manufacturing system in which the fermented and dried product obtained in the manufacturing system 1 is used in the cement manufacturing apparatus (for example, the cement clinker manufacturing apparatus 100). obtain.

FIG. 4 is a diagram showing an example of the cement clinker manufacturing apparatus 100. The cement clinker manufacturing apparatus 100 includes, for example, a suspension preheater 110, a rotary kiln 120, a calcining furnace 130, and a rotary kiln inlet foot portion 140. The suspension preheater 110 is provided with a raw material supply port 135A and an exhaust portion 150 at the upper portion. Further, the rotary kiln inlet foot portion 140 is also provided with the raw material supply port 135B, and the calcining furnace 130 is also provided with the raw material supply ports 135C and 135D. The rotary kiln 120 is provided with a burner 170 and a cooler 180.

The fermented dried product is introduced into the upper part of the suspension preheater 110 via, for example, the raw material supply port 135A, and is lowered in the suspension preheater 110 while being heated. Then, the fermented dried product is further heated in the calcining furnace 130 connected to the suspension preheater 110, and then introduced into the rotary kiln 120 via the rotary kiln inlet foot portion 140. The fermented and dried product introduced into the rotary kiln 120 is fired by the flame generated in the rotary kiln 120 by the burner 170. The fired raw material is cooled through the cooler 180 to become a target cement clinker and is discharged to the outside. By the above procedure, a cement clinker can be produced from a fermented dried product as a raw material.

As a method for treating the fermented dried product, for example, in addition to the above-mentioned introduction from the raw material supply port 135A, the introduction from the raw material supply port 135B provided on the side surface of the rotary kiln inlet foot portion 140, or a calcining furnace. It may be introduced from the raw material supply port 135C provided on the upper part of the 130, or may be introduced from the raw material supply port 135D provided on the side surface of the calcining furnace 130. Further, as a method of utilizing it as a fuel during cement production, the fermented dried product may be directly blown into the rotary kiln 120 from the burner 170 to be introduced, or a raw material supply port may be further provided near the burner to be blown into the rotary kiln 120. good. In these cases, the fermented and dried product has the advantage that it can be treated as a heat energy source in addition to being able to be treated as a cement clinker raw material. From the viewpoint of ease of operation, it is conceivable to introduce the fermented dried product from the vicinity of the foot portion 140 at the entrance of the rotary kiln. In any case, when the fermented dried product is introduced into the cement clinker manufacturing apparatus 100, the fermented dried product may be introduced alone or mixed with other cement clinker raw materials. good. The introduction of the fermented dried product may be carried out continuously or intermittently. Further, the fermented dried product may be introduced through one raw material supply port, or may be introduced through a plurality of raw material supply ports.

In cement factories, it is important to control the composition of the cement clinker produced. Therefore, from the viewpoint of ease of management, the amount of the fermented dried product used is pre-designed based on the composition of the target cement clinker, and the fermented product is introduced into the cement clinker manufacturing apparatus based on the designed amount of use. The fermented dried product may be treated as a raw material for cement clinker. Specifically, the production of cement such as the amount of auxiliary raw material added to the fermented raw material, the production rate of the fermented product (fermentation rate), the composition of the cement clinker raw material used at the same time other than the fermented dried product, and the mixing ratio thereof. The relationship between (at least one of) the information related to the conditions and the composition of the cement clinker produced is grasped in advance. Then, based on this information, the amount of fermented dried product used is designed. By performing such work in advance, stable operation management of the manufacturing apparatus can be performed. Further, by designing so as to increase the amount of the fermented and dried product used in the above design, it is possible to realize an increase in the waste intensity.

[Action]
As described above, according to the fermentation / drying apparatus and the fermentation / drying method described in the above-described embodiment, information on the temperature and the amount of air supplied into the container of the fermentation / drying apparatus and the container of the fermentation / drying apparatus. The heat of fermentation is calculated based on the information on the temperature and the amount of exhausted gas, and the air supply into the container is controlled based on the amount of heat of fermentation and the exhaust temperature. Therefore, the fermentation status in the container can be controlled more accurately, and the fermented and dried product can be produced more stably.

Conventionally, studies have been made on using the amount of heat of fermentation in the device as one of the fermentation indexes when controlling the fermentation in the container by adjusting the amount of air supplied to the fermentation / drying device. However, as a result of the examination by the inventors, if the amount of air supply is controlled according to the fluctuation of only the amount of heat of fermentation, the fluctuation range of the amount of air supply becomes large, insufficient air supply and excessive air supply frequently occur, and the temperature inside the container. Fermentation may become unstable due to large fluctuations in fermentation rate. On the other hand, in the above embodiment, the air supply into the container is controlled based on the exhaust temperature. According to the studies of the inventors, the exhaust temperature can also be an index related to the fermentation situation. Therefore, it is possible to more stably produce a fermented and dried product by controlling the air supply in consideration of the exhaust temperature in addition to the amount of heat of fermentation.

Further, when both the fermentation heat amount and the exhaust temperature are increasing, the air supply amount by the air supply means is increased, and when both the fermentation heat amount and the exhaust temperature are decreasing, the air supply amount by the air supply means is decreased. If the configuration is such that the fermentation status is changing, the status inside the container can be adjusted according to the amount of air supplied. Therefore, the fermented and dried product can be produced more stably.

In addition, by calculating the amount of heat of fermentation based on the difference between the amount of heat of exhaust gas related to exhaust gas and the amount of heat of air supply related to air supply, the amount of heat of fermentation associated with fermentation in the container can be grasped more accurately. The fermentation status can be managed more accurately based on the information.

Further, in the cement manufacturing system described in the above embodiment, cement is manufactured in the cement manufacturing apparatus using the fermented and dried product obtained in the fermentation drying apparatus. With such a configuration, the fermented and dried product can be more stably supplied for cement production.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications can be made.

For example, the configurations of the production system 1, the fermenter 2, the cement clinker production apparatus 100 and the like described above are examples, and can be appropriately changed.

Hereinafter, the contents of the present disclosure will be described in more detail with reference to Examples and Comparative Examples. However, the present disclosure is not limited to the following examples.

(Example)
^{Sewage sludge is added to a fermenter (capacity 39 m 3} , manufactured by Chubu Ecotech Co., Ltd .: C-40ET) having the same shape as the fermenter 2 described in the above embodiment, and various auxiliary materials are added to use seed sludge. The fermented and dried product was produced. The component of sewage sludge is sludge-like sludge (moisture content 80% to 85%) dehydrated by a filter press.

While adjusting the amount of sewage sludge and auxiliary materials in consideration of the fermentation situation in the fermenter, basically every day, at a predetermined time (between 9:00 am and 11:00 am), fermented and dried products are discharged from the sewage sludge outlet. It was taken out and the fermentation raw material was put in from the inlet. In addition, the fermentation process was continued while controlling the weight of the contents in the fermenter to be within a predetermined range.

On each day of the predetermined operation period (August 21st to August 25th), the weight W1 of the fermenter contents at 6:00 pm and the weight W2 of the fermenter contents at 6:00 am the next day after 12 hours have passed. And, the difference ΔW was calculated. Table 1 shows the amount of fermented raw material input and the weight of the fermenter contents (6 pm and 6 am) on each day.

ΔW shown in Table 1 is the amount of weight loss of the contents of the fermenter in 12 hours, and can be regarded as the sum of the amount of decomposition of organic matter in the fermenter and the amount of water evaporation from the tank. Therefore, the magnitude of ΔW can be an index of fermentation rate.

(Frequency control of air supply means based on fermentation heat quantity and exhaust temperature)
During the above operation period, the frequency of the air supply blower in the air supply means was controlled by the procedure shown in FIG. The amount of increase / decrease in the amount of air supply changed the inverter frequency of the air supply blower by 0.2 Hz. Further, the adjustment interval was set to a 3-minute interval as in the case shown in the example in the above embodiment. FIG. 5 shows changes in the heat of fermentation (heat of fermentation) and the exhaust temperature of the fermenter during the above period. Further, FIG. 6 shows a change (control result) in the frequency of the insufflation blower during the same period. The period 1 shown in FIGS. 5 and 6 indicates the period during which the fermentation raw material was started to be charged into the fermenter 2, the period 2 indicates the period during which the fermentation raw material is charged every day, and the period 3 indicates the fermentation raw material. Indicates the period during which the fermentation is not performed.

(Comparison example)
^{Sewage sludge is added and various auxiliary materials are added to the fermenter (capacity 39 m 3} , manufactured by Chubu Ecotech Co., Ltd .: C-40ET) having the same shape as the fermenter 2 described in the above embodiment in the same manner as in the embodiment. , A fermented and dried product was produced using seed sludge. The component of sewage sludge is sludge-like sludge dehydrated by a filter press.

Similar to the examples, on each day of the predetermined operation period (September 3 to September 8), the weight W1 of the contents of the fermenter at 6:00 pm and the fermenter at 6:00 am the next day after 12 hours have passed. The weight W2 of the contents was measured, and the difference ΔW was calculated. Table 2 shows the amount of fermented raw material input and the weight of the fermenter contents (6 pm and 6 am) on each day.

(Frequency control of air supply means based on the amount of heat of fermentation)
During the above operation period, the frequency of the air supply blower in the air supply means was controlled by the procedure shown in FIG. First, the control unit 9 calculates the amount of heat of fermentation H (step S11). Based on this result, the control unit 9 determines whether the amount of heat of fermentation H is increased as compared with the previous calculation result (S12). When the amount of heat of fermentation H is increased as compared with the previous calculation result (S12-YES), the control unit 9 increases the amount of airflow (air supply amount) to the fermentation tank 2 (S13). On the other hand, when the amount of heat of fermentation H has not increased as compared with the previous calculation result (S13-NO), the control unit 9 reduces the amount of airflow (air supply amount) to the fermentation tank 2 (S14). The control of the aeration amount (air supply amount) based on this determination was continued until the operation of the fermenter 2 was completed (S15-YES).

The procedure shown in FIG. 7 differs from the procedure in the embodiment shown in FIG. 3 in the following points. That is, the control performed in the comparative example is different from the embodiment in that the determination based on the exhaust temperature T is not performed. Other conditions are the same. That is, the amount of increase / decrease in the amount of air supply changed the inverter frequency of the fan air supply blower by 0.2 Hz. Further, the adjustment interval was set to a 3-minute interval as in the case shown in the example in the above embodiment.

FIG. 8 shows changes in the heat of fermentation (heat of fermentation) and the exhaust temperature of the fermenter during the above period. Further, FIG. 9 shows a change (control result) in the frequency of the insufflation blower during the same period. Periods 1 to 3 shown in FIGS. 8 and 9 are the same as in the examples.

Comparing the examples and the comparative examples, the average difference ΔW in a series of fermenter load change patterns (increase-steady-decrease) is 537 kg in the comparative example compared to 584 kg in the example, and the examples are compared. It was confirmed that it tended to be about 10% larger than the example. Regarding the fermentation heat and the exhaust temperature, the examples had a faster rise in temperature and fermentation heat in the period 1 (fermenter load increasing phase) and in the period 2 (fermenter load steady phase) than in the comparative example. It was confirmed that the fluctuations in temperature and fermentation heat were small, and that the temperature and fermentation heat declined slowly in period 3 (fermenter load reduction phase). Further, regarding the fluctuation of the actual air supply amount, in the example, the frequency rise is faster in the period 1, the frequency fluctuation is smaller in the period 2, and the frequency drop is gradual in the period 3 than in the comparative example. It was confirmed that. From the above, it is evaluated that in a series of fermentation tank load change patterns (increase-steady-decrease), the examples are more stable and actively fermented than the comparative examples. Further, in the period 2 which is the steady operation period, the frequency of the example is relatively lower than that of the comparative example by about 5 Hz, but as described above, the frequency of the example is larger than that of the comparative example for ΔW. Was confirmed. This is considered to indicate that the fermented dried product was efficiently produced even if the amount of air supplied to the fermenter 2 was small.

1 ... Manufacturing system, 2 ... Fermenter, 4 ... Air supply heater, 5 ... Air supply blower, 6 ... Dust removal tower, 7 ... Exhaust fan, 8 ... Cleaning and deodorizing tower, 9 ... Control unit, 21 ... Container, 22 ... Input Port, 23 ... Discharge port, 24 ... Stirring equipment, 24a ... Stirring blade, 24b ... Rotating shaft, 25 ... Air supply means, 26 ... Exhaust means, 100 ... Cement clinker manufacturing equipment.

Claims (7)

A container that accommodates fermentation raw materials containing sewage sludge and performs fermentation drying treatment while stirring the fermentation raw materials.
An air supply means for supplying air into the container and
An air supply information acquisition unit that acquires information related to the air supply temperature and the air supply amount of the gas supplied by the air supply means, and the air supply information acquisition unit.
Exhaust means for exhausting from the inside of the container and
An exhaust information acquisition unit that acquires information related to the exhaust temperature and displacement of the gas exhausted by the exhaust means, and an exhaust information acquisition unit.
It has a control unit that controls the air supply means and the exhaust means.
The control unit calculates the amount of heat of fermentation from the information acquired by the air supply information acquisition unit and the exhaust information acquisition unit, and controls the air supply means based on the heat of fermentation and the exhaust temperature. Drying device. The control unit increases the amount of air supplied by the air supply means when both the amount of heat of fermentation and the temperature of the exhaust are increasing, and when both the amount of heat of fermentation and the exhaust temperature are decreasing, the control unit increases the amount of air supplied by the air supply means. The fermentation / drying apparatus according to claim 1, wherein the amount of air supplied by the air supply means is reduced. The fermentation drying device according to claim 1 or 2, wherein the control unit calculates the fermentation heat amount based on the difference between the exhaust heat amount related to the exhaust gas and the air supply heat amount related to the air supply. The fermentation / drying apparatus according to any one of claims 1 to 3.
A cement manufacturing apparatus using a fermented and dried product obtained by the fermentation and drying treatment in the fermentation and drying apparatus, and a cement manufacturing apparatus.
Has a cement manufacturing system. It is a fermentation and drying method in a fermentation and drying device.
Fermentation raw materials containing sewage sludge are housed in a container, and the fermentation drying process is performed while stirring the fermentation raw materials in the container.
When performing the fermentation and drying process, air is supplied into the container and
When performing the fermentation and drying process, exhausting from the container and
Acquiring information on the air supply temperature and air supply amount of the gas to be supplied, and
Acquiring information on the exhaust temperature and displacement of the exhausted gas,
The amount of heat of fermentation is calculated based on the information on the air supply temperature and the amount of air supply and the information on the exhaust air temperature and the amount of exhaust gas, and based on the amount of heat of fermentation and the exhaust temperature, the inside of the container is introduced. Controlling the air supply and
Fermentation and drying methods, including. A method for producing cement clinker, wherein the cement clinker is produced from the fermented and dried product obtained by the method according to claim 5. A method for using a fermented dried product, which uses the fermented dried product obtained by the method according to claim 5 as a heat energy source.

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