JPH02217777A - Method and device for drying granular body - Google Patents

Abstract

PURPOSE:To obtain a given drying degree while shortening temperature rising time and preventing variability in stagnation and contrive the shortening of drying time by a method wherein jet stream layer drying and the moving layer drying of bodies to be dried, which have finished the jet stream layer drying already, are effected in parallel at the same time. CONSTITUTION:A supplying valve 3a at the lower part of a material supplying hopper 3 is opened and bodies to be dried or nylon chips 10 are thrown until they arrive at a predetermined height of layer in the annular section A of a jet stream layer drier 2, then, the supplying valve 3a is closed. At this moment, a moving layer drier 11 is filled with the nylon chips 10, which have finished jet stream layer drying already, high-temperature N2 gas, having the temperature of 130 deg.C for example, is injected through the multitude of small holes of a distributing tube 12 arranged in the lower zone of the drier 11 to make the gas flow upward through gaps between the filled nylon chips 10 and the speed of the gas is increased at the part of a throat to form jet stream layer and effect the preheating drying of the nylon chips 10 in the jet stream layer drier 2. Subsequently, the amount of the N2 gas is reduced and the nylon chips 10, stagnating in the jet stream layer drier 2 while being circulated, are droppin into the moving layer drier 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for drying granular materials, and in particular,
The present invention relates to a method and apparatus for drying granular materials that combine a spouted bed and a moving bed, suitable for drying water-absorbing resin chips containing internal water, such as nylon chips.

[Prior Art] Conventional 1 There is a conical rotary vacuum dryer 100 as shown in FIG. 6 as a granular material drying device for drying materials to be dried such as resin chips. Two conical containers 1O1 are combined and arranged so as to be freely rotatable. A steam jacket 102 and a steam bypass (heat transfer tube) 103 are provided inside the container 101, and heated steam is supplied from the outside to heat the inside of the conical container.

On the other hand, a gas suction port 104 is provided inside the container 101 to suck gas generated within the container 101. This container 101 is rotated twice by a rotating device 105 provided outside, and the material to be dried is stored in the container.
Hot gas is supplied from the bottom.

In the conical rotary vacuum dryer 100 configured in this way,
A material to be dried, such as a nylon chip, is supplied upward from the supply port 106, and the supply port 106 is closed.

Next, the one-cone rotary vacuum dryer 100 is rotated to supply steam to the steam jacket 102 and the steam bypass 1.03, thereby drying the material to be dried inside while heating it.

Additionally, a fluidized bed dryer is used as another conventional device.

As an example of this type of drying device, for example,
Publication No. 2555 discloses that hot air is introduced from below a rectifying net (perforated plate) to form a fluidized bed, and heat is transferred and moisture is transferred between the material to be dried and the hot air. An apparatus for drying is shown.

In addition, although not shown, there is a cylindrical moving bed dryer. This cylindrical moving bed dryer is designed to dry the material to be dried by supplying a cylindrical material and flowing the material in countercurrent.

By the way, conventionally, as mentioned above, the conical rotary vacuum dryer 1
00 and fluidized bed dryer 1 cylindrical moving bed dryers have been used, but since nylon has a wood-philic group called -NHCO-, absorbed moisture is absorbed not only as surface moisture but also as internal moisture. exists and drying is diffusion-limited,
It cannot be easily dried without raising the temperature.However, if the temperature is raised, in an atmosphere where oxygen is present, it will easily undergo oxidative deterioration and M change, making it impossible to maintain product quality, so it is dried in a vacuum atmosphere or N2 atmosphere. ing.

[The problem that the invention aims to solve! U] However,
When drying an object to be dried such as a nylon chip having such properties using a conventional dryer as described above, there are the following problems.

In the conical rotary vacuum dryer 100, heat is transferred between pellets, so it takes time to reach a uniform temperature. therefore.

For example, even when heated with steam at 120° C., it took 12 hours to dry from 1.0% moisture to the predetermined moisture content of 0.05%. Moreover, since this was a batch type, manual switching was required.

Fluidized bed drying equipment with a high heat transfer coefficient can quickly and uniformly reach a predetermined temperature.
It takes about 8 hours to dry with hot gas at 130° C. continuously, or about 6 hours in a batch method, to reduce the moisture content to the specified 0.05%. However, in order to make it a continuous device,
In order to reduce the variation in residence time due to particles, it was necessary to take measures such as using multiple stages, and the power of the blower for supplying hot gas was extremely large.

In addition, in the case of compounds that mix nylon with glass, etc., there are many types, and when changing types every few days, it is necessary to wash the inside of the dryer with water to prevent mixing. At this time, in a normal fluidized bed type drying apparatus having a rectifying network (perforated plate) type distributor, there is a problem that water enters the air chamber side.

In addition, although the cylindrical moving bed dryer is a continuous type, hot gas is supplied from the bottom and flows in countercurrent, so the temperature of the hot gas at the inlet decreases, so it takes time to reach the specified temperature. , the drying time is, for example, 110℃ hot gas and moisture 1.0
% to the specified moisture content of 0.05% takes nearly 13 hours.

In this way, the continuous fluidized bed dryer has the advantage that the temperature of the material to be dried rises quickly, but the residence time is uneven,
Moreover, the disadvantage is that the power of the hot gas supply blower for fluidization is very high, while the cylindrical moving bed dryer has the advantage that the residence time is uniform, but the temperature rise time is large11]. There are two disadvantages: it takes a long time.

Further, in other conventional examples, there is a problem that it takes a long time to raise the temperature.

The present invention has been made in view of the problems of the prior art described above, and its purpose is to shorten the temperature rise time by taking advantage of the respective characteristics of the spouted bed dryer and the moving bed dryer. It is an object of the present invention to provide a method and apparatus for drying granular materials, which can prevent fluctuations in retention, provide a constant degree of dryness, and shorten the overall drying time.

[Means for Solving the Problems 1 To Achieve the Object 1] In the present invention, a granular material to be dried is uniformly heated in a short time using a high-temperature gas in a spouted bed, and is heated at a constant temperature. When drying the spouted bed-dried material to a predetermined degree of dryness by drying the spouted-bed-dried material for a desired residence time in a moving bed using high-temperature gas, the spouted-bed drying and the The moving bed drying of the dried material after spouted bed drying was carried out at the same time.

In addition, as a drying device for granular materials to carry out this method, two vertical containers each having an inverted truncated round part at the lower part of the container are connected by piping, and the upper vertical container is connected by piping. A group of heat transfer tubes for flowing a high-temperature heat medium is provided in the lower part of the container, and a supply port and a gas outlet for the material to be dried are provided above the group of heat transfer tubes. Install a blow pipe.

The vertical container was configured as a spouted bed drying section, and the vertical container described later was configured as a moving bed dryer.

[Function] The granular material drying device of the present invention is provided with a spouted bed dryer in the upper stage and a moving bed dryer in the lower stage, and when drying the granular material, it is necessary to dry the granular material containing internal moisture. The material to be dried, such as granular nylon chips, first enters the spouted bed dryer, where it is turned into a jet by the high temperature gas rising from the moving bed dryer, and is uniformly heated and a predetermined amount of moisture is blown off. Secondary, it is dried to a certain extent in a relatively short time.

As a result, the drying material that has been dried to a certain extent in the spouted bed dryer is filled into the moving bed dryer in the lower stage, and the dried material that has been filled is placed between the moving bed dryer. It becomes a moving bed because it is extracted from the rotary valve at the bottom of the container, and in this moving bed, the high-temperature gas blown from the dispersion tube via the gas supply pipe at the bottom of the container passes between each particle of the material to be dried, is finally dried. In this moving bed dryer, sufficient residence time is allowed for drying, so drying is performed with no variation in residence time. Since the main drying in the fluidized bed dryer is carried out at the same time, the entire product can be dried to a certain degree in a relatively short time. When drying is carried out for a predetermined period of time in the spouted bed dryer as described above, a predetermined amount of the dried material dried in the moving bed dryer is extracted from the drying material outlet at the bottom of the container, and the material is dried at a constant rate in the spouted bed dryer. The material to be dried, which has been dried to a certain extent, passes through the throat section between the spouted bed dryer and the moving bed dryer, and is then drained and guided to the moving bed dryer. At the same time, new material to be dried is introduced into the spouted bed dryer from the supply port at the top of the container to a predetermined height, and the same drying operation is performed thereafter.

[Example] The present invention will be explained below based on the illustrated example. 1st
The figure is a longitudinal sectional view of the granular material drying device of the present invention, and FIG.
A sectional view taken from II-II in the figure, Figure 3 is m in Figure 2.
- sectional view of the gas supply pipe and dispersion pipe of the granular material drying apparatus of the present invention seen from It is a graph showing a drying process. This embodiment will be explained using FIG. 1, FIG. R2, FIG. 3, FIG. 4, and FIG. 5.

The granular material drying device 1 is configured with a spouted bed dryer 2 in the upper stage and a moving bed dryer 11 in the lower stage. In the moving bed dryer 11 in the section, it plays the role of main drying.

First, the configuration of the spouted bed dryer 2 will be described.

The spouted bed dryer 2 has a truncated conical cylinder part 2c facing upward at the top, a cylindrical straight body part 2b at the middle stage, and an inverted conical conical cylinder facing downward at the bottom stage. In the figure, the white arrows indicate the gas flow direction, and the black arrows indicate the gas flow direction. First, a brief description of the spouted bed, which indicates the flow direction of particles of the material to be dried, will be given. The spouted layer generally consists of a spout part B, which is a gas passage formed by spouting upward from a throat part 6, which is a gas inlet of the inverted truncated conical cylindrical part 2a at the lowest stage, and a spout part B, which is a gas passage formed by spouting upward from the throat part 6 which is the gas introduction port of the inverted truncated conical cylindrical part 2a at the lowest stage. The raw material of nylon chips 10, which had been slidingly moved from the conical cylindrical part 2a, was then transported to the upper part of the spout part B along with the gas, and the moved nylon chips 1OJil were given by the gas on the way. It loses interlocking energy and falls into the annular part A between the cylindrical straight body part 2b and the spout part B, where gas resistance is low. The fallen nylon chip 10 raw material forms an annular part A in the form of a moving layer. The nylon chip 10 in the annular part A slides through the cylindrical body part 2b and the inverted truncated conical cylindrical part 2a of the lower green tier, moves downward, and is finally discharged into the gas passing through the spout part B. At the same time, the nylon chip 10 raw material discharged into the gas is entrained in the upper part with the upward flow of gas in the spout part B, where it loses energy and is deposited again on the interface of the annular part A. A spouted bed with circulating flow is formed. In the spouted bed dryer 2 that utilizes such a spouted bed, in order to supply the nylon chips 10, which are dry raw materials, to the spouted bed dryer 2, an appropriate amount of air is supplied from the lower part of the raw material supply hopper 3 toward the cylindrical straight body portion 2b. The pipe 3b is arranged at an angle, and the supply valve 3a is installed at an appropriate position on the pipe 3b, and the nylon chips 10 of the raw material supplied to the raw material supply hopper 3 are opened and closed as necessary. By doing so, it can be supplied to the spouted bed dryer 2. Further, the inlet part of the cyclone 4 is connected to the truncated conical cylindrical part 2C via the pipe 4a, and the lower part of the cyclone 4 is connected to the cylindrical straight body part 2b via the pipe 4b. The nylon chips 1O entrained in the gas discharged from the gas outlet 16 at the top of the vessel 2 are separated into gas and nylon chips 10 by the cyclone 4.0 Separated nylon chips 10
The gas is returned to the spouted bed dryer 2 from the bottom of the cyclone 4 through a pipe 4b arranged in the cylindrical straight body part 2b, and the gas is sent from the top of the cyclone 4 through a pipe 4C to the next process (not shown). In the 0th step, for example, it is dehumidified by passing it through a bag filter (not shown) or a dehumidifier for continuous circulation of N2 gas, pressurized again with a blower, and then heated to a predetermined temperature with a heat exchanger. It is heated and finally blown into the layer from a gas supply pipe 9 of a moving bed dryer 11, which will be described later. Here, in order to suppress the amount of nylon chips 10 that are discharged together with the gas from the gas discharge port 16, a cap 7 is provided in the upper region of the spout part B in the jet dryer 2. This is awarded by the gas at spout part B.

The inertial force of the nylon chip 10 that is moved upward is used to collide with the camp hat 7, and has the role of forcibly preventing the amount of scattering. Here, it is desirable that the cone angle of the inverted truncated conical cylindrical portion 2a at the bottom of the spouted bed dryer 2 is at least equal to or greater than the repose angle of the nylon chip IO. A heat exchanger tube group 5 is provided across the shaped portion 2a. As shown in Fig. 1, this heat transfer tube group 5 is used to forcibly heat the particle group moving from the upper part of the hollow part A toward the lower part with a heat medium such as steam, in addition to heating with gas. It is provided on the outside of the annular part A, that is, on the inner side wall of the cylindrical straight body part 2b and the truncated conical part 2a.

A heat exchanger tube group 5 is provided inside the annular part A, that is, between the spout parts B, and is folded back in the vertical direction and continuous.
High-temperature steam flows inside as the aforementioned high-temperature heat medium. Here, the position of the tip of the heat exchanger tube group 5 is preferably set to, for example, up to 2/3 of the projected cross-sectional area of the annular part A.
This can be done by extending the tip of the heat transfer tube group 5 to the boundary area between the annulus part A and the spout part B in order to increase the amount of heat transferred from the heat transfer tube group 5 to the nylon chip 0. Under the influence of the mixed phase cooling of the gas rising in the area and the nylon chip IO, the rate at which the nylon chip 10 collides with the heat transfer tube group 5 increases, which deforms or cracks the nylon chip 10, causing the nylon chip IO to collide with the heat exchanger tube group 5. This may cause powdering and deterioration of product quality. Conversely, if the tip of the heat exchanger tube group 5 is placed closer to the inner wall of the spouted bed dryer 2, it will not be affected by the spout portion B, but the heat transfer activity of the heat exchanger tube group 5 will be reduced, and the heat Unless the temperature of the steam as a medium is changed, the amount of heat transferred from the heat exchanger tube group 5 to the nylon chip 10 will decrease, and the meaning of arranging the heat exchanger tube group 5 in the spouted bed dryer 2 will diminish. .

In addition, the lowermost inverted truncated conical cylindrical portion 2a of the spouted bed dryer 2
A throat portion 6 having an appropriate diameter is provided between the truncated conical cylindrical portion 11c provided at the top of the moving bed dryer 11, and the spouted bed dryer 2 is used to dry the fluid to a desired moisture level in advance. It serves as a connecting pipe for sending the dried nylon chips 10 to the moving bed dryer 11 in the next step, and the drying gas, such as N2 gas, sent to the moving bed dryer 11 is transferred to the moving bed dryer II. It rises at 0, 1~0, 2m/sea in the inner part, and further increases to 8~10m/sea in the slow part 6. As described above, the average gas velocity at the throat portion 6 changes depending on the average diameter, specific gravity, and shape of the nylon tip.
It is necessary that the gas velocity be such that it overcomes the resistance of the gas flow velocity in the throat portion 6 and does not fall from the spouted bed dryer 2 to the moving bed dryer 11. This is because the nylon chips 1 and 0 supplied from the raw material supply hopper 3 into the spouted bed dryer z are dried by the enthalpy held by the gas within a certain residence time, and the amount of water in the nylon chips 10 is reduced to a predetermined level. This is because it is necessary to reduce the retained moisture content to .

On the other hand, the moving bed dryer 11, like the spouted bed dryer 2 described above, has a truncated conical cylindrical part 11C at the top, a cylindrical straight body part 11b at the middle part, and a reverse truncated cylindrical part 11b at the bottom. It is composed of a conical cylindrical part 11a, and in order to dry the nylon chip 10 below the cylindrical straight body part 11b, a plurality of branch pipes 12 are branched from the gas supply pipe 9 for supplying gas.
passes through the cylindrical straight body part 11b at a predetermined pitch, and then traverses the container 11b and is disposed in a direction substantially perpendicular to the cylindrical straight body part 11b. Further, each gas supply pipe 9 is connected to a gas header (not shown), and a high temperature N2 gas supply source (not shown) is further connected to the gas header. As shown in Figure 2.

A large number of dispersion pipes 12 are connected to the gas supply pipe 9 and arranged at a predetermined pitch, and high-temperature N2 gas is blown out from numerous small holes provided in the upper part 13 of the dispersion pipes 12. That is, in the cross section of the dispersion tube 12, the upper part 13
has a pointed roof-like shape, and this roof part (slope part) is formed from a member such as punched metal in which countless small holes are bored, and the diameter of the small holes is, for example, im.
It is said to be about m. Moreover, by making the upper part 13 of the dispersion pipe 12 into a roof-like pointed shape as described above.

When the nylon chip 10 housed inside is pulled out,
The structure is such that the nylon chip 10 remains in the upper part 13 of the dispersion tube 12 and does not change color due to yellowing or the like when exposed to high temperatures (see FIG. 2).

Further, gas is blown into the moving bed dryer 11 from this gas supply pipe 9 via a dispersion pipe 12.

N2 from countless small holes drilled in the upper part 13 of the dispersion pipe 12.
Gas is blown in an amount that does not fluidize the nylon chips contained within the moving bed dryer 11. Further, at the lower end of the inverted truncated conical cylindrical part 11a at the lowest part of the moving bed dryer 11, a dried nylon chip 10 with a reduced diameter in a conical shape is provided.
A conical buckle 15 is attached to the inside of the outlet 14 for the dried material to uniformly draw out the dried material in the container itb from the cross section of the container. Also,
For example, a rotary valve 17 is attached to the lower end of the drying material outlet 14 for the nylon chips 1O, and while sealing the drying gas blown into the moving bed dryer 11, only the nylon chips 1O are continuously removed. It can be discharged. For this reason, the nylon chips 10 deposited in the moving bed dryer 11 are discharged through the upper part of the spouted bed dryer 2 and the falling material to be dried, and the lower part through the rotary valve 17 as a discharge valve. Because of this, the flow pattern of the nylon chip 10 exhibits the state of a moving layer. Further, since the moving bed dryer 11 has a circular cross-sectional shape, the flow of the dried material descending when the dried material is discharged is smooth, and there is no accumulation at the corners.

The thus constructed granular material drying apparatus operates as follows.

First, the supply valve 3a at the bottom of the raw material supply hopper 3 attached to the spouted bed dryer 2 is opened, and the layer height of the annular part A is raised to a predetermined height.
After inserting the nylon chip 10 containing, for example, 1% water to a depth of 5 mm, the supply valve 3a is closed. Incidentally, at the time when the introduction of the nylon chips 10 is started in this manner, the moving bed dryer 11 is already filled with nylon chips 10 that have been subjected to spouted bed drying.

Then, the dispersion pipe 1 installed in the lower part of the moving bed dryer 1
For example, high-temperature N of 130°C is released from the large number of small holes in
N2 gas is spouted out and flows upward through the gap between the nylon chips 10 filled in the moving bed dryer 11, and these N2 gases are formed into a spouted bed at a speed in section A-4. The nylon chips 10 in the spouted bed dryer 2 are preheated and dried.

Then, it is dried in the spouted bed for a predetermined period of time (for example, about 20 minutes), heated uniformly to a predetermined temperature in the spouted bed dryer 2, and at the same time dried to a certain degree. Once the gas velocity at the throat portion 6 is reduced by reducing the N2 gas flow, the nylon chips 1O circulating and staying in the spouted bed dryer 2 will be
The nylon chips fall into the moving bed dryer 11 by overcoming the drag force due to the gas velocity in the throat portion 6, and the pressure loss indicating the state of retention of the nylon chips 1O in the spouted bed dryer 2 becomes small. When the pressure loss has decreased to a certain value, the amount of gas blown into the moving bed dryer 11 is increased again to the original state, and the supply valve 3a at the bottom of the raw material supply hopper 3 is opened to reduce the pressure inside the spouted bed dryer 2. Nylon chips 10 are fed until the loss becomes constant.

When performing the following operation, if you check the correlation between the pressure loss value in the spouted bed dryer 2 and the inflow of NZ gas into the moving bed dryer 11 on the back page, you can use this to perform the cascade Operation by control is also possible, and the supply valve 3 can be opened and closed electrically, so that when the pressure loss in the spouted bed dryer 2 decreases, the supply valve 3 opens, and conversely, the pressure loss decreases to a predetermined value. It is also easily possible to carry out cascade control so that it closes when the

Next, while rotating the rotary pulp 17, which is the discharge valve of the drying material discharge port 14, to a predetermined rotation speed, the nylon chips 10 that have been dried to a desired value can be discharged from the system. Moving bed drying'J: The N2 gas supplied into the layer from multiple dispersion tubes 12 to All is transferred to the dispersion tube 1
2 Nylon chips 10 are ejected from the numerous small holes on the top.
The high-temperature N2 gas that passes through and rises between each particle allows sufficient residence time for drying.

The drying process of the nylon chip 10 follows the steps shown in FIG. Due to this.

Each particle of the nylon chip 10 is dried with no variation in residence time. Note that the drying action in the spouted bed dryer 2 and the drying action in the moving bed dryer 11 are performed simultaneously. In addition, since there is no rectifying plate in the spouted bed dryer 2, the nylon chips 10 do not remain in the layer, and furthermore, there is no possibility that the nylon chips 10 will be exposed to high temperature gas many times and the quality will deteriorate due to discoloration and deterioration. This also applies to the moving bed dryer 11, and since the upper part 13 of the 5-distribution tube 12 is roof-shaped, no residual nylon chips 10 in the T* layer can be seen.

Further, since a conical baffle 15 is provided at the upper center of the drying material outlet 14, the nylon chips 10 dried in the moving bed dryer 11 are uniformly extracted from the container. For this reason, there is no possibility that the nylon chips 10 in that part will become too dry due to partial retention and that the quality will deteriorate.

According to the experimental results using such a drying method, the N2 gas temperature was set at 130°C and the moisture content of the nylon chips was set at 1.0°C, provided that the drying material did not undergo oxidative deterioration.
Total drying time is about 7 hours to change from % to 0.05%
This is a short drying time that is approximately the same as drying using a conventional fluidized bed dryer alone. Moreover, in this case, there was no variation in the residence time of the material to be dried, and it was possible to obtain a product in which each particle was uniform and had a constant degree of dryness. Moreover, of course, no oxidative deterioration occurred due to the use of N2 gas.

Furthermore, when changing the items to be dried, the inside could be easily washed with water.

In the case of this embodiment, by setting the filling volume of the lower moving bed dryer 11 to be several times to several tens of times larger than the drying capacity of the spouted bed dryer 2, the moving bed can dry more evenly. It is possible to obtain a product with a dryness with little variation.

Furthermore, in the present embodiment described above, the case where the inside of the moving bed dryer 11 is dried by the moving layer has been explained, but for example, the rotary valve 17 attached to the lower part of the container to be dried is discharged 14
If it is driven intermittently, it can be used as a fixed bed dryer without gradually lowering the packed bed during operation, and in this case, dryness can be achieved with less variation.

Although the description has been made using the nylon chips 10 as the material to be dried, it goes without saying that other dried granular materials can also be used and obtained.

[Effects of the Invention] As detailed above, in the method for drying granular materials of the present invention, the overall drying time of the material to be dried is shortened, and the overall power required for supplying hot gas is reduced. Furthermore, it is possible to obtain a product with a uniform dryness and a constant degree of dryness with little variation. In addition, since a group of heat exchanger tubes is installed in the annular part of the spouted bed dryer, the material to be dried can be heated and dried separately from the drying by the jet gas. It can be reliably and easily dried to a predetermined degree of dryness in a short period of time.

In addition, since there are no places in the spouted bed dryer or moving bed dryer where the material to be dried remains, there is no deterioration in quality due to deterioration or discoloration due to long-term exposure to high-temperature gas.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the granular material drying apparatus of the present invention, FIG. 2 is a sectional view taken from II-II in FIG. 1, and FIG. 3 is a sectional view of the granular material of the present invention seen from II-II in FIG. 4 is a sectional view of the gas supply pipe and dispersion pipe of the drying device, FIG. 4 is a sectional view taken from V-■ in FIG. The figure is a cross-sectional view of a prior art granule dryer. 1... Granular material dryer, 2... Spouted bed dryer,
3... Raw material supply hotspots, 4... Cyclone, 5... Heat exchanger tube group, 6... Throat part 7
...jinkasa, 9...gas supply pipe, 1
0...MUI product (nylon tip). 11... Moving bed dryer, 12... Dispersion tube, 1
4...Dried material discharge port, 15.../<Tuffle. 16... Gas discharge port, A... Annular part. B... Spout part. Patent applicant: Ube Industries, Ltd. Figure 2 j 4 Conn

Claims (2)

[Claims] (1) The material to be dried, which is a granular material, is heated uniformly in a spouted bed for a short period of time using high-temperature gas, and dried to a certain extent, and then the material to be dried, which has been dried in the spouted bed, is When drying with gas for a desired residence time in a moving bed to achieve a predetermined degree of dryness, the spouted bed drying and the moving bed drying of the material to be dried that has already been spouted bed drying are performed simultaneously in parallel. A method for drying granular materials, characterized by: (2) Two vertical containers each having an inverted truncated conical head at the bottom of the container are connected by piping, and a group of heat transfer tubes is provided to flow a high temperature heat medium downward inside the upper vertical container. A supply port and a gas discharge port for the material to be dried are provided above the group of heat transfer tubes, and a high temperature gas blowing pipe is provided in the lower part of the lower vertical container, and the vertical container is used as a spouted bed drying section; A granular material drying device characterized in that a vertical container described later is used as a moving bed dryer.