JP2023007563A - Drying system and drying method - Google Patents

Abstract

To provide a drying system low in frequency of maintenance and capable of properly drying powder and grain.SOLUTION: A drying system 1 includes a flash dryer 21, a storage portion 23, a fluidized bed dryer 25, and a supply switch portion 24. The flash dryer 21 has a drying passage 21a, and dries powder and grain by making the powder and grain as an object to be dried and gas for drying the powder and grain flow to the drying passage 21a. The storage portion 23 temporarily stores the powder and grain dried by the flash dryer 21. The fluidized bed dryer 25 is disposed at a downstream side with respect to the flash dryer 21, and has a drying space to fluidize and dry the powder and grain stored in the drying space. The supply switch portion 24 can switch between a closed state of keeping the storage without supplying the powder and grain to the fluidized bed dryer 25 by closing a passage connected to the fluidized bed dryer 25 from the storage portion 23, and a supply state of supplying the powder and grain stored in the storage portion 23 to the fluidized bed dryer 25.SELECTED DRAWING: Figure 1

Description

The present invention mainly relates to a drying system for drying granular materials.

Patent Literature 1 discloses a fluidized bed drying apparatus that continuously dries powder. A fluidized bed dryer has a plurality of processing chambers partitioned by partition walls. In each processing chamber, the granular materials are sequentially introduced, and the dried granular materials are sequentially discharged.

Patent Literature 2 discloses a drying apparatus in which a flash dryer is provided above a fluidized bed dryer. The material dried by the flash dryer is further dried by a fluidized bed dryer.

Patent Document 3 discloses an apparatus comprising a flash drying tube and a dryer. Hot air is flowing through the airflow drying pipe, and the object to be dried is dried by flowing the object to be dried through the airflow drying pipe. The material to be dried, which has been primarily dried in the flash drying tube, is put into the dryer. In the dryer, the material to be dried is dried by flowing the material to be dried in a superheated steam atmosphere.

JP 2016-125697 A Japanese Utility Model Laid-Open No. 61-60088 JP 2009-133591 A

In the fluidized bed drying apparatus of Patent Document 1, since the granular material with a large amount of moisture is supplied to the processing chamber, the granular material tends to adhere to the inner wall of the processing chamber. Therefore, it is necessary to frequently perform maintenance for cleaning the inner wall of the processing chamber. In the apparatuses of Patent Documents 2 and 3, when the material to be dried is continuously supplied to the fluidized bed dryer/drying chamber, the material to be dried may be dried unevenly and may not be sufficiently dried.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a main object thereof is to provide a drying system that requires less maintenance and is capable of properly drying powders.

The problems to be solved by the present invention are as described above. Next, the means for solving the problems and the effects thereof will be described.

A first aspect of the present invention provides a drying system having the following configuration. That is, the drying system includes a flash dryer, a storage section, a fluidized bed dryer, and a supply switching section. The airflow dryer has a drying path, and the powder is dried by flowing a powder or granular material to be dried and a gas for drying the powder or granular material through the drying path. Allow the granules to dry. The storage unit temporarily stores the powder dried by the flash dryer. The fluidized bed dryer is provided downstream of the flash dryer, has a drying space, and fluidizes and dries the granular material accommodated in the drying space. The supply switching unit has a closed state in which storage is maintained without supplying the powder or granular material to the fluidized bed dryer by closing a path leading from the storage unit to the fluidized bed dryer, and It is possible to switch between a supply state in which the stored granular material is supplied to the fluidized bed dryer.

A second aspect of the present invention provides the following drying method. That is, the drying method includes a flash drying process, a storage process, a supply process, and a fluidized bed drying process. In the airflow drying step, the powdery or granular material to be dried and the gas for drying the powdery or granular material are caused to flow through a drying path formed in the airflow dryer, thereby drying the powdery or granular material. dry. In the storing step, the powder or granular material dried in the airflow drying step is stored in a storing portion. In the supply step, the granular material stored in the storage unit is supplied to a fluidized bed dryer. In the fluidized bed drying step, a fluidized bed dryer having a drying space is used to fluidize and dry the powder or granular material accommodated in the drying space.

As a result, the granules dried in the flash dryer and having a reduced water content are supplied to the fluidized bed dryer, so that the granules are less likely to adhere to the inner wall of the fluidized bed dryer. In addition, in the flash dryer, the flow velocity of the gas in the passage is high, and the concentration of the powder is low relative to the gas. Hateful. As described above, the above drying system reduces the frequency of maintenance for both the flash dryer and the fluidized bed dryer. In addition, since the powder particles dried by the flash dryer are collected and supplied to the fluidized bed dryer, the powder particles can be dried uniformly, so that the powder particles can be dried appropriately.

ADVANTAGE OF THE INVENTION According to this invention, the frequency of maintenance is low and the drying system which can dry a granular material appropriately can be provided.

The figure which shows the state during drying with a fluid bed dryer in the drying system of 1st Embodiment. The figure which shows the state which discharges the granular material dried with the fluid bed dryer in the drying system of 1st Embodiment. The figure which shows the state which supplies a new granular material to a fluid bed dryer in the drying system of 1st Embodiment. 4 is a flowchart showing processing performed by the pointing device; The figure which shows the structure of the drying system of 2nd Embodiment. The figure which shows the structure of the drying system of 3rd Embodiment.

Embodiments of the present invention will now be described with reference to the drawings. First, a drying system 1 of a first embodiment will be described with reference to FIGS. 1 to 3. FIG.

A drying system 1 includes a plurality of devices for drying powder. Granules are terms that indicate powders, granules (including granules), and mixtures of powders and granules. Granules may be pharmaceuticals, foods, or other substances. In the following description, upstream/downstream of the flow of particulate matter or gas may simply be referred to as upstream/downstream.

As shown in FIG. 1 , the drying system 1 includes a supply section 10 , a drying section 20 , a blower section 30 and a discharge processing section 40 .

The supply unit 10 supplies the drying unit 20 with the powder or granular material to be dried. The granular material supplied by the supply unit 10 contains a large amount of water. The supply unit 10 includes a portion for storing the granular material and a portion for continuously feeding the granular material. With this configuration, the supply unit 10 continuously supplies the powder to the drying unit 20 .

The drying section 20 dries the granular material supplied by the supplying section 10 . The drying unit 20 includes a flash dryer 21, a first collector 22, a storage unit 23, a supply switching unit 24, a fluidized bed dryer 25, a discharge switching unit 26, a first collection container 27, Prepare.

The flash dryer 21 has a housing, and a drying path 21a is formed in the housing. The drying path 21a is an elongated path, and includes curved, arcuate, or folded portions in order to increase the length of the path. The granular material supplied by the supply unit 10 flows through the drying path 21a. Further, the high-temperature gas supplied by the air blower 30 (details will be described later) flows through the drying path 21a. As a result, the granular material is dried (primary drying) by flowing through the drying path 21a together with the high-temperature gas.

The first collector 22 is a cyclone type separator, and separates the granules and the high-temperature gas that flow together. Granules separated by passing through the first collector 22 fall into a storage section 23 below and are stored. Also, the high-temperature gas separated by passing through the first collector 22 is discharged to the outside by a discharge processing unit 40 (details will be described later).

The storage part 23 is a hopper-like container in which the granular material separated by the first collector 22 is temporarily stored. A supply hole for supplying powder is formed in the lower part of the reservoir 23 , and the supply hole of the reservoir 23 can be closed by the supply switching part 24 . The reservoir 23 is not limited to a hopper-like container, and may be a container having an appropriate shape capable of discharging the granular material.

A supply switching unit 24 is arranged below the storage unit 23 . By closing the supply hole of the storage unit 23, the supply switching unit 24 maintains storage without supplying the powder stored in the storage unit 23 to the fluidized bed dryer 25 (FIGS. 1 and 2). 2) and a supply state ( FIG. 3 ) in which the powder stored in the storage section 23 is supplied to the fluidized bed dryer 25 by opening the supply hole of the storage section 23 .

The operation of the supply switching unit 24 is controlled by the indicating device 100 . The pointing device 100 includes a CPU, ROM, RAM, and the like. The instruction device 100 can control the drying system 1 by reading the program stored in the ROM into the RAM and executing the program. In this embodiment, the supply switching unit 24 is operated by an actuator such as a motor or cylinder. The instruction device 100 can switch the supply switching unit 24 between the closed state and the supply state by instructing this actuator.

A fluidized bed dryer 25 is arranged below the supply switching unit 24 . The fluidized bed dryer 25 performs secondary drying for further drying the granular material that has been primarily dried by the flash dryer 21 . The fluidized bed dryer 25 has a drying space for secondary drying. The fluidized bed dryer 25 has a container shape, and the inside thereof is a drying space. A high-temperature gas is supplied to the fluidized bed dryer 25 by the air blower 30 . The hot gas is supplied upward from the lower part of the drying space of the fluidized bed dryer 25 . As a result, the granular material flows in the drying space, so that the granular material can be dried.

Although the ratio of the amount of water removed by primary drying and secondary drying is not particularly limited, in the present embodiment, the amount of water removed by primary drying is greater than the amount of water removed by secondary drying. This is because it becomes more difficult to remove the water as the water content of the powder becomes lower. However, the amount of water removed by the primary drying may be less than the amount of water removed by the secondary drying.

Granules that have undergone secondary drying by the fluidized bed dryer 25 are discharged into the first collection container 27 below. Specifically, a discharge hole (passage) is formed in the lower part of the fluidized bed dryer 25 for discharging the granular material downward. A discharge hole of the fluidized bed dryer 25 is closed by a discharge switching unit 26 . Specifically, the discharge switching unit 26 has a closed state (FIGS. 1 and 3) in which the discharge hole is closed so that the powder is not discharged, and a drying state in the fluidized bed dryer 25 by opening the discharge hole. It is possible to switch between a discharge state ( FIG. 2 ) in which the powder or granular material that has been completed is discharged to the first collection container 27 . The operation of the discharge switching section 26 is controlled by the instruction device 100 . In addition, instead of the first collection container 27, a transport device (conveyor or suction device) for sending the granular material to the next step may be provided.

Here, the flash dryer 21 is a continuous drying device. The continuous type is a method in which the granular material is continuously supplied, and the supplied granular material is dried while being sent out without being stored, and the granular material is discharged.

In contrast, the fluidized bed dryer 25 is of a batch type. The batch method is a method in which a predetermined amount is defined as one unit, and one unit of granular material is collectively dried. Therefore, first, a predetermined amount of granular material is supplied to the fluidized bed dryer 25, and drying starts after the supply of the granular material is completed. After the drying is completed, all (that is, a predetermined amount) of the granular materials supplied to the fluidized bed dryer 25 are collectively discharged into the first recovery container 27 .

In other words, while the flash dryer 21 continuously discharges the granular material, the fluidized bed dryer 25 is not configured to continuously dry the granular material. In addition, it is not preferable to continuously supply the powder to the fluidized bed dryer because the powders having different degrees of drying are mixed, resulting in uneven drying.

In this regard, in the present embodiment, by providing the storage section 23, the continuously supplied granular material can be temporarily stored. In addition, since the primary drying of the granules has been completed, the granules are difficult to integrate with each other. After that, after a predetermined amount of granular material is stored in the storage unit 23 , the granular material is supplied to the fluidized bed dryer 25 . This makes it possible to achieve both continuous drying and batch drying. In addition, since the primary drying of the granular material has been completed, the granular material is less likely to adhere to the inner wall of the fluidized bed dryer 25 . Therefore, maintenance frequency can be reduced.

As described above, the granules are continuously supplied from the flash dryer 21 to the reservoir 23, and the amount of granules supplied to the reservoir 23 per unit time is constant. Further, the above-described one unit in which the secondary drying is performed in the fluidized bed dryer 25 is constant. Therefore, the pointing device 100 of this embodiment switches the state of the supply switching unit 24 according to a predetermined time schedule. Moreover, the time during which secondary drying is performed in the fluidized bed dryer 25 is also constant. Accordingly, the instruction device 100 switches the state of the discharge switching section 26 according to a predetermined time schedule.

The air blowing section 30 sends the drying gas to the drying section 20 . The air blower 30 includes an air filter 31 , an outside air adjustment valve 32 , a blower fan 33 , a heater 34 , a first high temperature gas adjustment valve 35 , a second high temperature gas adjustment valve 36 and a third high temperature gas adjustment valve 37 . and a fourth hot gas regulating valve 38 . Although outside air is used as the drying air in this embodiment, another gas may be used, or another gas may be mixed with the outside air.

The air filter 31 removes dust and dirt contained in the outside air. The outside air adjustment valve 32 can adjust the amount of suction of gas and the presence or absence of suction of gas. The blower fan 33 sends the gas toward the drying section 20 .

The gas sent out by the blower 30 is heated by the heater 34 to become the first high-temperature gas. The hot gas is sent to the flash dryer 21 through the first hot gas regulating valve 35 and to the fluidized bed dryer 25 through the second hot gas regulating valve 36 . Also, the gas sent out by the blower 30 is sent to the fluidized bed dryer 25 via a path that does not pass through the heater 34 . That is, the fluidized bed dryer 25 is supplied with the gas that has passed through the heater 34 (high temperature gas) and the gas that has not passed through the heater 34 (normal temperature gas, outside air).

In general, the flash dryer 21 uses gas at a relatively high temperature. On the other hand, in the fluidized bed dryer 25, a gas with a lower temperature than that in the flash dryer 21 is used. If a high output heater for heating the gas supplied to the flash dryer 21 and a low output heater for heating the gas supplied to the fluidized bed dryer 25 are provided, the cost of the heaters increases. In this regard, in the present embodiment, only the gas that has passed through the heater 34 is supplied to the flash dryer 21 , so the first high-temperature gas having a relatively high temperature is supplied to the flash dryer 21 . On the other hand, the fluidized bed dryer 25 is supplied with the second high-temperature gas, which is a mixture of the first high-temperature gas that has passed through the heater 34 and the outside air that has not passed through the heater 34, so that a relatively low-temperature gas is supplied. be done. Thereby, gas of appropriate temperature can be supplied to the flash dryer 21 and the fluidized bed dryer 25 without providing two heaters.

By changing the degree of opening of the second high-temperature gas regulating valve 36, the mixing ratio of the high-temperature gas and the normal temperature gas can be changed. For example, the temperature of the gas supplied to the fluidized bed dryer 25 can be stabilized by changing the degree of opening of the second high-temperature gas control valve 36 based on the detection result of a temperature sensor (not shown).

A branch is formed in the path for supplying the second hot gas to the fluidized bed dryer 25 . A supply path 61 , which is one of the branched paths, is connected to the fluidized bed dryer 25 . A bypass route 62 , which is the other of the branched routes, is connected to the discharge processing section 40 without passing through the fluidized bed dryer 25 . The second high-temperature gas supplied to the fluidized bed dryer 25 is discharged to the discharge processing section 40 through the filter and the discharge path 63 .

A third high temperature gas regulating valve 37 is provided in the supply path 61 . By changing the degree of opening of the third high-temperature gas control valve 37, the flow rate of the second high-temperature gas supplied to the fluidized bed dryer 25 can be adjusted. The second high-temperature gas can be prevented from being supplied to the fluidized bed dryer 25 by closing the third high-temperature gas control valve 37 . A fourth hot gas regulating valve 38 is provided in the bypass path 62 . By changing the degree of opening of the fourth high-temperature gas regulating valve 38, the flow rate of the second high-temperature gas flowing through the bypass path 62 can be adjusted. As a result, the flow rate of the second high-temperature gas can be made the same when the second high-temperature gas flows through the fluidized bed dryer 25 and when the second high-temperature gas flows through the bypass passage 62 .

The discharge processing unit 40 generates a suction flow for moving the powder and discharging the high-temperature gas. The discharge processing unit 40 includes a suction fan 41 , an exhaust adjustment valve 42 , a second collector 43 , a second collection container 44 and an exhaust switching valve 45 .

The suction fan 41 generates a suction flow. The functions of the suction flow generated by the suction fan 41 are to send the granular material, to generate a swirling flow that separates the high-temperature gas and the granular material in the first collector 22, and to to exhaust the second hot gas supplied to the . The suction fan 41 is connected to the second collector 43 via the exhaust control valve 42 . By changing the degree of opening of the exhaust adjustment valve 42, the strength of the suction flow can be adjusted.

The second collector 43 is a filter type separator called a bag filter or the like. The second collector 43 is connected downstream of the first collector 22 in the flow direction of the high-temperature gas. The second collector 43 separates the granular material that has not been separated by the first collector 22 and is contained in the high-temperature gas. The granular material separated by passing through the second collector 43 is stored in the second recovery container 44 . The high-temperature gas separated by passing through the second collector 43 is discharged by the discharge processing section 40 .

The second collector 43 is connected to the exhaust switching valve 45 via the suction path 64 . The exhaust switching valve 45 is a three-way valve and is connected to the suction path 64 , the supply path 61 and the bypass path 62 . The exhaust switching valve 45 switches between a state in which the suction path 64 and the supply path 61 are connected (exhaust state, FIG. 1) and a state in which the suction path 64 and the bypass path 62 are connected (closed state, FIGS. 2 and 3). It is configured to be switchable. In a state where the exhaust switching valve 45 connects the suction path 64 and the exhaust path 63 , the second high-temperature gas supplied to the fluidized bed dryer 25 is exhausted to the exhaust processing section 40 . Further, in a state where the exhaust switching valve 45 connects the suction path 64 and the bypass path 62 , the path connecting the fluidized bed dryer 25 and the suction fan 41 is closed, and the second high-temperature gas supplied to the bypass path 62 is closed. The gas is discharged to the discharge processing section 40 .

Next, with further reference to FIG. 4, the flow of processing for drying the powder will be described.

First, the instruction device 100 closes the supply switching unit 24, closes the discharge switching unit 26, connects the bypass path 62 and the suction path 64 to the exhaust switching valve 45, and closes the exhaust switching valve 45. (S101). After that, the indicator device 100 starts supplying the granular material by the supply unit 10, and starts primary drying of the granular material by the flash dryer 21 (S101).

Next, the instruction device 100 switches the supply switching unit 24 from the closed state to the supply state, and supplies the powder to the fluidized bed dryer 25 (S102, FIG. 3). At this time, since the discharge switching unit 26 is in the closed state, the supplied granular materials do not drop from the fluidized bed dryer 25 into the first collection container 27 . Furthermore, since the exhaust switching valve 45 is in a closed state, no gas flow is generated from the fluidized bed dryer 25 toward the discharge processing unit 40, so that the supplied powder or granular material can be appropriately accumulated in the fluidized bed dryer 25. can be done.

Next, the instruction device 100 switches the supply switching unit 24 from the supply state to the closed state after the time (supply time) required to supply a predetermined amount of powder to the fluidized bed dryer 25 has elapsed (S103 ). As a result, the state in which the granular material is supplied to the fluidized bed dryer 25 is switched to the state in which the granular material is stored in the storage unit 23 .

Next, the instruction device 100 connects the discharge path 63 and the suction path 64 to the exhaust gas switching valve 45 to put the exhaust gas switching valve 45 into the exhaust state (S104). As a result, the second high-temperature gas is supplied to the fluidized bed dryer 25, and secondary drying by the fluidized bed dryer 25 is started (S104, FIG. 1).

Next, after the drying time has elapsed, the instruction device 100 connects the bypass path 62 and the suction path 64 to the exhaust switching valve 45 to close the exhaust switching valve 45 (S105). As a result, the second high-temperature gas is not supplied to the fluidized bed dryer 25 but flows to the exhaust treatment section 40 .

Next, the instruction device 100 switches the discharge switching unit 26 from the closed state to the discharge state, and discharges the granular material to the first collection container 27 (S106, FIG. 2). At this time, since the exhaust switching valve 45 is in the closed state, no gas flows from the fluidized bed dryer 25 to the discharge processing unit 40, so that the movement of the powder discharged to the first collection container 27 is suppressed. , the powder can be appropriately discharged to the first recovery container 27 .

Next, after the ejection time has elapsed, the instruction device 100 switches the ejection switching unit 26 from the ejection state to the closed state (S107). After that, the pointing device 100 performs the processing of steps S102 to S107 again. As described above, the powder particles continuously supplied from the flash dryer 21 can be dried by the batch-type fluidized bed dryer 25 .

Next, with reference to FIG. 5, the drying system 1 of 2nd Embodiment is demonstrated. In addition, in the description of the second embodiment and thereafter, the same or similar members as those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof may be omitted.

Although the supply unit 10 of the first embodiment supplies powder to the drying unit 20, the supply unit 10 of the second embodiment supplies granules (a type of powder) produced from powder to the drying unit. 20. Specifically, the supply unit 10 includes a powder supply unit 11 and a granulation unit 12 . The powder supply unit 11 supplies the powder stored in the storage unit as in the first embodiment. The granulation unit 12 agitates the powder supplied by the powder supply unit 11 to generate granules. The granulation unit 12 continuously supplies the generated granules to the flash dryer 21 . In the first embodiment and the second embodiment, only the objects to be dried are different, and the flow of the drying process is the same.

In addition, when the granules are dried in a batch type with a fluidized bed dryer, the granules may be integrated while they are stored in the storage section 23 . In this regard, in the present embodiment, the granules supplied by the supply unit 10 are continuously dried by the flash dryer 21 . Therefore, when the granules are stored in the storage unit 23, the water content of the granules is low, so that the granules are difficult to integrate with each other.

Next, with reference to FIG. 6, the drying system 1 of 3rd Embodiment is demonstrated.

The drying system 1 of the first embodiment is configured to include one reservoir 23 and one fluidized bed dryer 25 . Instead of this, the drying system 1 of the third embodiment includes two sets of devices related to secondary drying (hereinafter referred to as secondary drying devices 28). The secondary drying device 28 includes a first collector 22, a storage section 23, a supply switching section 24, a fluidized bed dryer 25, a discharge switching section 26, a first recovery container 27, a third high-temperature gas control valve 37, and a 4 hot gas regulating valve 38 is included.

The drying system 1 further includes a drying destination switching unit 29 . The drying destination switching unit 29 is positioned downstream of the flash dryer 21 and upstream of the first collector 22 . The drying destination switching unit 29 can switch between a state in which the granulated material dried by the flash dryer 21 is sent to one first collector 22 and a state in which it is sent to the other first collector 22. . The operation of the drying destination switching unit 29 is controlled by the indicating device 100 .

By providing two sets of secondary drying devices 28 , while secondary drying is being performed in one secondary drying device 28 , the powder can be supplied to the other secondary drying device 28 . Therefore, for example, when the drying time of the fluidized bed dryer 25 is relatively long, it is preferable to employ the drying system 1 of the third embodiment.

As described above, the drying system 1 of the present embodiment includes the flash dryer 21, the storage unit 23, the fluidized bed dryer 25, and the supply switching unit 24, and performs the following drying method. The airflow dryer 21 has a drying path 21a, and powder particles are dried by flowing a powder or granular material to be dried and a gas for drying the powder or granular material through the drying path 21a. Dry the body (air drying process). The storage unit 23 temporarily stores the powder dried by the flash dryer 21 (storage step). The fluidized bed dryer 25 is provided downstream of the flash dryer 21, has a drying space, and fluidizes and dries the powder or granular material contained in the drying space (fluidized bed drying process). . The supply switching unit 24 maintains storage without supplying the powder to the fluidized bed dryer 25 by closing the path leading from the storage unit 23 to the fluidized bed dryer 25, and stores in the storage unit 23. The supply state of supplying the powdered granular material to the fluidized bed dryer 25 can be switched, and the granular material is supplied by switching to the supply state (supplying step).

As a result, the powder or granule dried by the flash dryer 21 and having a reduced moisture content is supplied to the fluidized bed dryer 25 , so that the powder or granule is less likely to adhere to the inner wall of the fluidized bed dryer 25 . In addition, in the airflow dryer 21, since the flow velocity of the gas in the passage is high and the concentration of the powder is low with respect to the gas, the surface of the powder is quickly dried, and the powder adheres to the inner wall of the passage. hard to do. As described above, in the drying system 1 of the present embodiment, maintenance frequency of both the flash dryer 21 and the fluidized bed dryer 25 is reduced. In addition, since the powders dried by the flash dryer 21 are collected and supplied to the fluidized bed dryer 25, the powders can be uniformly dried, so that the powders can be dried appropriately. .

In the drying system 1 of this embodiment, the fluidized bed dryer 25 is positioned below the reservoir 23 .

Thereby, the powder can be supplied from the reservoir 23 to the fluidized bed dryer 25 using gravity.

The drying system 1 of this embodiment includes a suction fan 41 , an exhaust switching valve 45 and an indicating device 100 . The suction fan 41 generates a suction flow. The exhaust switching valve 45 closes the path connecting the suction fan 41 and the fluidized bed dryer 25 to the exhaust state for discharging the gas for drying the powder or granular material by applying a suction flow to the fluidized bed dryer 25. and a closed state in which the fluidized bed dryer 25 is not affected by the suction flow. The instruction device 100 operates the supply switching unit 24 and the exhaust switching valve 45 . The instruction device 100 switches the supply switching unit 24 from the closed state to the supply state after the exhaust switching valve 45 is switched from the exhaust state to the closed state.

As a result, the suction flow does not act on the fluidized bed dryer 25 while the powdery material is being supplied from the reservoir 23 to the fluidized bed dryer 25, so that the powdery material can be appropriately supplied.

The drying system 1 of the present embodiment has a closed state in which the route (discharge hole) for discharging the powder from the fluidized bed dryer 25 is closed, and a discharge in which the route for discharging the powder from the fluidized bed dryer 25 is opened. A discharge switching unit 26 capable of switching between a state and a state is provided. After the exhaust switching valve 45 is switched from the exhaust state to the closed state, and after the exhaust switching unit 26 is switched from the exhaust state to the closed state, the instruction device 100 indicates that the new powder or granular material is to be supplied to the fluidized bed dryer. 25, the supply switching unit 24 is switched from the closed state to the supply state.

Accordingly, after the dried powder is discharged, new powder can be supplied to the fluidized bed dryer 25 .

In the drying system 1 of the present embodiment, the granules are granules produced by the granulator, and the granules produced by the granulator are continuously sent to the flash dryer 21 .

As a result, the granules containing a large amount of moisture are continuously dried, so that the granules can be prevented from being integrated with each other.

The drying system 1 of this embodiment includes a heater 34 that heats the air supplied to the flash dryer 21 and the fluidized bed dryer 25 . The first high-temperature gas heated by the heater 34 is supplied to the flash dryer 21 , and the second high-temperature gas whose temperature is lowered by mixing the first high-temperature gas with outside air is supplied to the fluidized bed dryer 25 .

As a result, the number of heaters can be reduced compared to a configuration in which separate heaters are provided for the flash dryer 21 and the fluidized bed dryer 25 .

Although the preferred embodiments of the present invention have been described above, the above configuration can be modified, for example, as follows.

In the above embodiment, the instruction device 100 switches the supply switching unit 24, the discharge switching unit 26, the exhaust switching valve 45, etc. according to a predetermined time schedule. Instead of this, a sensor for measuring the progress of drying and discharging in the fluidized bed dryer 25 is provided, and based on the detection result of the sensor, the supply switching unit 24, the discharge switching unit 26, the exhaust switching valve 45, etc. are switched. good too.

In the above-described embodiment, the first collector 22, the reservoir 23, and the fluidized bed dryer 25 are arranged side by side in the height direction, but they may have different positional relationships. That is, the powder may be moved not only by free fall due to gravity, but also by using a conveyer, suction flow, or the like.

The flowcharts shown in the above embodiments are examples, and some of the processes may be omitted, the contents of some of the processes may be changed, or new processes may be added.

Reference Signs List 1 drying system 20 drying unit 21 flash dryer 23 storage unit 24 supply switching unit 25 fluidized bed dryer

Claims (7)

It has a drying path, and an air flow for drying the powder by flowing a powder that is an object to be dried and a gas for drying the powder through the drying path. a dryer;
a reservoir for temporarily storing the powder or granular material dried by the flash dryer;
A fluidized bed dryer that is provided downstream of the flash dryer, has a drying space, and dries the powder or granular material accommodated in the drying space by fluidizing it;
A closed state in which storage is maintained without supplying the powder or granular material to the fluidized bed dryer by closing the path leading from the storage unit to the fluidized bed dryer, and the powder stored in the storage unit a supply switching unit capable of switching between a supply state for supplying the body to the fluidized bed dryer;
A drying system comprising: A drying system according to claim 1, comprising:
A drying system, wherein the fluidized bed dryer is positioned below the reservoir. 3. A drying system according to claim 1 or 2,
a suction fan for generating a suction flow;
An exhaust state in which the gas for drying the powder is discharged by applying the suction flow to the fluidized bed dryer, and a path connecting the suction fan and the fluidized bed dryer is closed and the suction flow is performed. an exhaust switching valve capable of switching between a closed state that does not act on the fluidized bed dryer, and
an instruction device that operates the supply switching unit and the exhaust switching valve;
with
The drying system, wherein the indicating device switches the supply switching unit from the closed state to the supply state after the exhaust switching valve switches from the exhaust state to the closed state. A drying system according to claim 3, wherein
a discharge switching unit capable of switching between a closed state in which the route for discharging the granular material from the fluidized bed dryer is closed and a discharge state in which the route for discharging the granular material from the fluidized bed dryer is opened; prepared,
After the exhaust switching valve is switched from the exhaust state to the closed state, and after the exhaust switching unit is switched from the exhaust state to the closed state, the indicator device is configured to display a new powder or granular material. is supplied to the fluidized bed dryer by switching the supply switching unit from the closed state to the supply state. A drying system according to any one of claims 1 to 4,
A drying system according to claim 1, characterized in that said granules are granules produced by a granulator, and said granules produced by said granulator are continuously sent to said flash dryer. A drying system according to any one of claims 1 to 5,
A heater for heating the air supplied to the flash dryer and the fluidized bed dryer,
A first high-temperature gas heated by the heater is supplied to the flash dryer, and a second high-temperature gas whose temperature is lowered by mixing the first high-temperature gas with outside air is supplied to the fluidized bed dryer. Characterized drying system. A flash drying step of drying the powder by flowing a powder to be dried and a gas for drying the powder through a drying path formed in the flash dryer. ,
a storage step of storing the powder or granular material dried in the airflow drying step in a storage unit;
a supply step of supplying the granular material stored in the storage unit to a fluidized bed dryer;
A fluidized bed drying step of fluidizing and drying the granular material contained in the drying space using a fluidized bed dryer having a drying space;
A drying method comprising:

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