JP2015224826A - Drying tower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce pressure loss of drying gas while avoiding increase in the cost regarding equipment, operation and maintenance, and a height of a tower, in a drying tower having a counterflow type moving bed.SOLUTION: A drying tower 2 includes a tower type drying vessel 10 into which a dried object is charged from a top and through which the dried object is discharged from a bottom, and an obstacle 60 disposed in the drying vessel 10 in such a manner of reducing a flow passage area of the dried object so as to obstruct downward movement of the dried object. An inside of the drying vessel 10 is virtually partitioned into an upper drying chamber 10a and a lower drying chamber 10b at the boundary of obstacle 60, and a drying gas injection port 16 for introducing the drying gas and an exhaust port 17 for discharging the drying gas after coming in contact with the dried object are respectively provided in the upper drying chamber 10a and the lower drying chamber 10b. The exhaust port 17 of the lower drying chamber 10b is opened to a gap V formed below the obstacle, in which the dried object does not exist.

Description

  The present invention relates to a drying tower having a countercurrent moving bed.

  Conventionally, a drying tower having a countercurrent moving bed is known. For example, in the drying tower shown in FIG. 3 of Patent Document 1, the adsorbent in the drying container is discharged from the bottom and the adsorbent is newly supplied from the top, and superheated steam is introduced into the drying container. In this drying tower, a countercurrent moving bed is formed by the adsorbent that moves downward in the drying container and the superheated steam that rises so as to face the flow of the adsorbent. In the drying tower having the counter-current moving bed as described above, the object to be dried that moves downward in the drying container comes into contact with the drying gas that rises so as to face the flow of the object to be dried. The material to be dried is heated and dried.

JP 2013-121562 A

  In the drying tower, not only the object to be dried is heated but also the object to be dried is dried until the humidity becomes a predetermined value or less. Therefore, it is desirable to continuously vent a large amount of drying gas in the drying tower as compared with a heat treatment apparatus intended for simple heating. However, as the height of the moving bed increases, the pressure loss of the drying gas that moves up the moving bed increases. Therefore, in order to ventilate a large amount of drying gas continuously, a high output blower is required. However, since the high-power blower is expensive and huge, and the capacity of the blower is limited, it is not desirable to compensate for the pressure loss of the drying gas with the blower capacity of the blower.

  In order to reduce the pressure loss of the drying gas rising up the drying container, it is considered that a plurality of drying containers are provided in the drying tower in the vertical direction, and the drying gas is introduced and discharged independently in each drying container. Yeah. Usually, when the moving layer is formed in the drying container, a discharge device for discharging the dried substance quantitatively is provided below the drying container in order to adjust the moving speed of the moving layer.

  When a drying tower is provided with a plurality of drying containers as described above, a discharge device corresponding to the number of drying containers is required. Therefore, the pressure loss of the drying gas can be reduced by increasing the number of drying containers. However, the increase in the number of discharge devices increases the cost for equipment, operation and maintenance, and increases the Inconveniences such as a further increase in height occur.

  The present invention has been made in view of the above circumstances, and is a drying tower having a countercurrent moving bed, while avoiding an increase in costs related to equipment, operation and maintenance, and an increase in tower height. An object of the present invention is to provide a drying tower capable of suppressing the pressure loss of the drying gas.

The drying tower according to the present invention is
A tower-shaped drying container in which a material to be dried is input from the top and the material to be dried is discharged from the bottom;
An obstacle provided in the drying container so as to reduce a flow path area of the object to be dried, while preventing a downward movement of the object to be dried while maintaining a laminar flow of the object to be dried, An obstacle that virtually divides the inside of the drying container into an upper drying chamber and a lower drying chamber with an obstacle as a boundary;
A first flow path member provided at a lower portion of each of the upper drying chamber and the lower drying chamber and having a drying gas jet port for ejecting a drying gas;
A second flow path member provided at the upper part of each of the upper drying chamber and the lower drying chamber and having an exhaust port for discharging the drying gas after coming into contact with the object to be dried.
The exhaust port of the lower drying chamber is open to a gap formed under the obstacle where the object to be dried does not exist.

  In the drying tower having the above-described configuration, the obstacle is prevented from moving downward to the object to be dried. Therefore, a void without the object to be dried is formed below the obstacle. Therefore, the drying gas after being introduced into the lower drying chamber and coming into contact with the object to be dried flows into a gap having a smaller pressure loss than the upper drying chamber. In the upper drying chamber, most of the introduced drying gas rises and is discharged from the discharge port of the upper drying chamber. Therefore, the introduction and discharge of the drying gas are performed independently in the upper drying chamber and the lower drying chamber. Therefore, the pressure loss of the drying gas can be suppressed as compared with the case where the drying gas is conducted from the bottom to the top of the drying container.

  Further, since the introduction and discharge of the drying gas are performed independently in each drying chamber, there is no need to provide a discharge device or the like between the drying chambers. Therefore, it is possible to avoid an increase in costs related to facilities, operation and maintenance due to an increase in the number of discharge devices, and an increase in tower height.

  Furthermore, in the drying tower having the above-described configuration, a plurality of drying chambers are formed in the upper and lower portions in the drying container, but an object to be dried moves continuously through the plurality of drying chambers. Although the flow path area of the object to be dried is partially reduced by the obstacle, the movement of the object to be dried from the upper drying chamber to the lower drying chamber is maintained, and a moving layer having an appropriate moving speed is formed.

  In the drying tower, the obstacle may be a taper forming body that decreases a flow path area of the object to be dried downward. In this case, it is desirable that the generatrix of the taper surface of the taper forming body and the vertical direction form an angle in a range larger than 0 ° and smaller than 60 °.

  According to the above drying tower, an obstacle that can hold the movement of the dried material from the upper drying chamber to the lower drying chamber while restricting the movement of the gas from the lower drying chamber to the upper drying chamber is simplified. This structure can be realized without the need for driving power. Therefore, it is possible to suppress an increase in costs related to the equipment, operation, and maintenance of the drying tower.

  In the drying tower, the obstacle may be a plurality of rod-like bodies arranged in a direction substantially orthogonal to the moving direction of the object to be dried.

  According to the above drying tower, an obstacle that can hold the movement of the dried material from the upper drying chamber to the lower drying chamber while restricting the movement of the gas from the lower drying chamber to the upper drying chamber is simplified. This structure can be realized without the need for driving power. Therefore, it is possible to suppress an increase in costs related to the equipment, operation, and maintenance of the drying tower.

  According to the drying tower according to the present invention, it is possible to suppress the pressure loss of the drying gas while avoiding an increase in costs related to equipment, operation and maintenance and an increase in tower height.

It is a block diagram which shows schematic structure of the drying equipment provided with the drying tower which concerns on one Embodiment of this invention. It is a block diagram which shows schematic structure of the drying equipment provided with the drying tower which concerns on the modification 1. FIG. It is a block diagram which shows schematic structure of the drying equipment provided with the drying tower which concerns on the modification 2. FIG.

  The drying tower 2 according to the present invention is used for drying granular materials such as synthetic resins, foods, feeds, fertilizers, chemicals, ceramics, and sludge. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram illustrating a schematic configuration of a drying facility 1 including a drying tower 2 according to an embodiment of the present invention. The drying facility 1 includes a drying tower 2, a discharge device 3, a drying gas supply device 4, and a charging device 5. Hereinafter, each component of the drying equipment 1 will be described in detail.

  The drying tower 2 includes a tower-shaped drying container 10 whose longitudinal direction is the vertical direction. An inlet 13 is provided at the top of the drying container 10, and an outlet 14 is provided at the bottom. The material to be dried (wet powder) is fed to the charging port 13 by the charging device 5, and the material to be dried is charged into the drying container 10 through the charging port 13. In addition, the discharge device 3 discharges the dried product (dried granular material) to the outside through the discharge port 14. In the drying container 10, the material to be dried is continuously or intermittently extracted from the discharge port 14 by the operation of the charging device 5 and the discharging device 3, and a new material to be dried is supplied from the charging port 13. The object to be dried is lowered by its own weight from the top to the bottom.

  Between the top part and the bottom part of the drying container 10, the throttle part 6 which restrict | limits the flow of to-be-dried material is provided. The sectional area of the internal space of the drying container 10 is reduced by the throttle portion 6 with respect to the downward distance. The throttle unit 6 is formed by an obstacle 60 that prevents a part of the objects to be dried from moving downward while maintaining a laminar flow of the moving layer of the objects to be dried. The to-be-dried object that is prevented from moving downward by the obstacle 60 avoids or comes into contact with the obstacle 60 and moves downward. For this reason, a void V in which an object to be dried does not exist is formed below the obstacle 60.

  In the throttle unit 6 according to this embodiment, a taper forming body 61 formed on the inner wall of the drying container 10 is used as an obstacle 60. The inlet 61 a of the taper forming body 61 coincides with or is close to the inner wall surface of the drying container 10. Further, the taper forming body 61 has a tapered surface 61c that is narrowed down, and an outlet 61b having a smaller diameter than the inlet 61a below the inlet 61a.

  The drying container 10 is virtually divided into an upper upper drying chamber 10a and a lower lower drying chamber 10b with the obstacle 60 (the outlet 61b of the taper forming body 61) as a boundary. Here, “virtually divided” means that there is actually no entity (such as a shutter) that separates the upper drying chamber 10a and the lower drying chamber 10b, and the upper drying chamber 10a and the lower drying chamber are not separated. The chamber 10b is in direct communication. In each of the upper drying chamber 10a and the lower drying chamber 10b, a drying gas jet port 16 for introducing a drying gas is provided in the lower portion, and the drying gas after contacting the object to be dried is discharged in the upper portion. An exhaust port 17 is provided. The exhaust port 17 is formed in a flow path member 19 provided on the wall surface of the drying container 10, and the flow path member 19 is connected to the exhaust pipe 18. Then, the drying gas containing moisture in the drying container 10 is discharged through the exhaust pipe 18.

  The exhaust port 17 of the lower drying chamber 10 b opens to the gap V formed by the obstacle 60. In the present embodiment, the exhaust port 17 opens in the wall surface of the drying container 10 just below the taper forming body 61.

  The charging device 5 is a device that continuously or intermittently and quantitatively feeds an object to be dried to the charging port 13 of the drying container 10, and is provided on the top of the drying container 10. The charging device 5 according to the present embodiment includes a screw feeder and a hopper so that a substance to be dried can be quantitatively supplied into the drying container 10. In this configuration, the material to be dried stored in the hopper is supplied into the drying container 10 by a fixed amount by a screw feeder. However, the charging device 5 is not limited to the screw feeder, and a known powder and granular constant supply means such as a rotary feeder or a conveyor can be used as the charging device 5. Further, the charging device 5 can be omitted. Moreover, it is desirable that the material to be dried supplied to the drying container 10 is distributed and supplied from above the drying container 10, and a mechanism for dispersing the material to be dried may be provided in the charging device 5.

  The discharge device 3 is a device for discharging a dry matter from the discharge port 14 to the outside continuously or intermittently and quantitatively in the dry container 10, and is provided at the lower part of the dry container 10. The discharge device 3 according to the present embodiment is a table feeder that quantitatively sends dry matter from the inside of the drying container 10 to the outside, and includes a rotor having a vertical rotation axis, and drive means (not shown) that rotationally drives the rotor. It has. However, the discharge device 3 is not limited to a table feeder, and a known powder discharge unit such as a rotary feeder can be used as the discharge device 3.

  The drying gas supply device 4 is a device that supplies a drying gas (hot air) to the drying gas jets 16 of the drying chambers 10a and 10b. The drying tower 2 is provided with a flow path member 46 in which each drying gas jet 16 is formed. The flow path member 46 may be annular or straight. The drying gas supply device 4 according to the present embodiment includes a drying gas supply pipe 41 connected to the flow path member 46, a blower 42 that pumps the drying gas to the drying gas supply pipe 41, and a drying state. And a flow rate adjusting valve 44 provided for each drying gas jet 16 in order to control the amount of air blown to each drying gas jet 16. According to the drying gas supply device 4 having such a configuration, a controlled amount of drying gas can be independently supplied to the lower portions of the drying chambers 10a and 10b. In this embodiment, the drying gas is hot air (dried air), but superheated steam may be used as the drying gas.

  Next, the flow of drying of an object to be dried by the drying facility 1 having the above-described configuration will be described.

  In the drying container 10, the material to be dried is extracted from the discharge port 14 by the discharge device 3, and the new material to be dried is supplied from the input port 13 by the input device 5, so The dried product is moving downward due to its own weight. In each drying chamber 10a, 10b of the drying container 10, the supplied drying gas flows from the bottom to the top in the opposite direction to the flow of the object to be dried. In this way, a counter-current moving layer is formed in each of the drying chambers 10a and 10b, and the object to be dried and the drying gas are continuously contacted. Due to the contact between the object to be dried and the drying gas, the water adhering to the object to be dried is heated and evaporated to dry the object to be dried.

  Most of the drying gas introduced through the drying gas outlet 16 of the upper drying chamber 10a passes upward in the upper drying chamber 10a (that is, opposite to the flow of the object to be dried), and the remaining gas. The part flows downward along the flow of the material to be dried. By directly contacting the drying gas introduced into the upper drying chamber 10a and the wet object to be dried in the upper drying chamber 10a, the moisture adhering to the object to be dried is heated and evaporated, The material to be dried is dried. The drying gas (including moisture volatilized from the object to be dried) after coming into contact with the object to be dried is discharged to the outside from the exhaust port 17 of the upper drying chamber 10a.

  Further, almost all of the drying gas introduced through the drying gas outlet 16 of the lower drying chamber 10b passes upward in the lower drying chamber 10b (that is, facing the flow of the object to be dried). . When the drying gas introduced into the lower drying chamber 10b is in direct contact with the wet object to be dried in the lower drying chamber 10b, the water adhering to the object to be dried is heated and evaporated. Then, the material to be dried is dried.

  In the throttle portion 6, there is a gap V where no material to be dried exists below the taper forming body 61, and the gas below the taper forming body 61 (specifically, the tapered surface 61c) has a small pressure loss. Induced to flow to V. Accordingly, most of the drying gas (including moisture volatilized from the material to be dried) that has risen in the lower drying chamber 10b flows into the gap V and is discharged to the outside from the exhaust port 17 of the lower drying chamber 10b. That is, the drying gas that is dampened by contacting with the object to be dried in the lower drying chamber 10b does not flow into the upper drying chamber 10a from the lower drying chamber 10b. Therefore, it is possible to improve the drying efficiency of the object to be dried in the upper drying chamber 10a. A part of the drying gas that has flowed into the lower drying chamber 10b from the upper drying chamber 10a is also exhausted from the exhaust port 17 of the lower drying chamber 10b.

  In order to form the flow of the drying gas as described above in the throttle portion 6, the angle γ formed by the generatrix of the tapered surface 61c of the conical taper forming body 61 and the vertical direction is larger than 0 ° and smaller than 60 °. An angle in the range is desirable (0 ° <γ <60 °). When the angle γ is 0 ° or less, the taper forming body 61 cannot function as the narrowed portion 6 and no pressure loss difference is generated between the gap V and the upper drying chamber 10a. As a result, the amount of gas that forms a counterflow in the upper drying chamber 10a is reduced, and the wet gas flows from the lower drying chamber 10b, so that the drying efficiency is reduced. On the other hand, when the angle γ is 60 ° or more, the angle formed by the tapered surface 61c and the horizontal surface becomes smaller than the repose angle, and there is a possibility that the object to be dried may stay or segregate in the tapered member 61. It is known that the angle of repose is determined by the size of the particles and the roundness and shape of the corners of the particles. As a reference example, the repose angle of an object to be dried (for example, silica gel) having an average particle diameter of 3 mm is approximately 30 °. Therefore, in this case, if the angle γ exceeds 60 °, the angle formed between the tapered surface 61c and the horizontal plane is smaller than the repose angle, and there is a possibility that the object to be dried is retained or segregated. In the above, the average particle size is a volume-based relative particle amount of 50 when a sample is measured using a particle size distribution measuring apparatus based on a laser diffraction / scattering method and a particle size distribution (cumulative distribution) is obtained. % Particle diameter (median diameter). Needless to say, the material to be dried and its average particle size are not limited to the above-mentioned reference examples. In addition, although the taper surface 61c of the taper formation body 61 which concerns on this embodiment is a linear taper whose diameter changes linearly with respect to distance, the taper surface 61c may be an exponential function type or a parabolic taper.

  In the drying tower 2 described above, a moving layer continuous to the drying chambers 10a and 10b of the drying container 10 is formed. That is, the movement of the drying gas is limited by the throttle unit 6, but the movement of the object to be dried is not limited. Therefore, the laminar flow of the moving layer by the material to be dried is maintained, and problems such as clogging of the material to be dried do not occur.

  And since introduction and discharge | emission of the gas for drying are performed in each drying chamber 10a, 10b. Therefore, compared with the case where the drying gas is conducted from the bottom to the top of the drying container 10, the pressure loss of the drying gas can be suppressed, and the blower 42 can be a small one. Moreover, since the drying chambers 10a and 10b are continuous, the discharge device 3 is not required between the drying chambers 10a and 10b. Therefore, it is possible to avoid an increase in costs related to equipment, operation and maintenance due to an increase in the number of discharge devices 3 and an increase in tower height.

  Further, since the throttle portion 6 is formed by an obstacle 60 having a simple shape (in this embodiment, a taper forming body 61), the drying gas is introduced and discharged independently in each of the drying chambers 10a and 10b. No complicated mechanism or driving force is required. Therefore, an increase in costs related to the equipment, operation and maintenance of the drying equipment 1 can be suppressed.

  Further, since the drying gas is introduced and discharged independently in each of the drying chambers 10a and 10b, there is a difference in the flow rate, humidity, and temperature of the introduced drying gas in each of the drying chambers 10a and 10b. it can. For example, if a drying gas having a lower humidity is introduced into the upper drying chamber 10a, drying of the object to be dried in the upper drying chamber 10a that is wetter than the object to be dried in the lower drying chamber 10b is promoted. Can be made.

[Modification 1]
Next, the modification 1 of the said embodiment is demonstrated. FIG. 2 is a configuration diagram illustrating a schematic configuration of the drying facility 1 including the drying tower 2 (2B) according to the first modification. The drying tower 2B according to Modification 1 is different from the drying tower 2 according to the above-described embodiment in that the obstacle 60 of the throttle unit 6 is a plurality of rod-shaped bodies 62. And the drying tower 2B which concerns on the modification 1 fulfill | performs the drying function similar to the drying tower 2 which concerns on embodiment, and has the same characteristics except the obstruction 60 of the aperture | diaphragm | squeeze part 6 being the several rod-shaped body 62. FIG. Have. Therefore, in the description of the drying tower 2B according to the modified example 1, the same or similar members as those of the above-described embodiment are denoted by the same reference numerals in the drawings, and the redundant description is omitted.

  As shown in FIG. 2, the throttle unit 6 of the drying tower 2 </ b> B according to Modification 1 includes a plurality of rod-like bodies 62 arranged in the horizontal direction as obstacles 60. At least one rod-like body 62 is located immediately above the exhaust port 17 of the lower drying chamber 10b so that a gap V in which no material to be dried exists is formed at and near the exhaust port 17 of the lower drying chamber 10b. Be placed.

  Each rod-like body 62 has an inclination in which an upward surface faces from top to bottom. As a result, the object to be dried that has come into contact with the rod-shaped body 62 from above can move downward along the surface of the rod-shaped body 62. Although the longitudinal cross-sectional shape of each rod-shaped body 62 shown in FIG. 2 is circular, the longitudinal cross-sectional shape of the rod-shaped body 62 may be a semicircle, a triangle, or a quadrangle.

  In the squeezed portion 6, a gap V in which an object to be dried does not exist is formed below each rod-like body 62. In the above-described embodiment, the gap V is formed around the outlet 61b of the taper forming body 61, whereas in the first modification, the gap V can be formed at any position where the rod-like body 62 is disposed. For example, the air gap V can also be formed in the exhaust port 17 and its vicinity of the lower drying chamber 10 b and the central portion of the drying container 10.

  In FIG. 2, the plurality of rod-like bodies 62 are arranged in a single upper and lower stage, but the throttle unit 6 may be provided with a plurality of rod-like bodies 62 in a plurality of upper and lower stages. Further, although the plurality of rod-like bodies 62 are arranged in one direction, the plurality of rod-like bodies 62 may be arranged in an intersecting manner so as to have a mesh shape in plan view.

[Modification 2]
Next, a second modification of the above embodiment will be described. FIG. 3 is a configuration diagram illustrating a schematic configuration of a drying facility 1 including a drying tower 2 (2C) according to Modification 2. The drying tower 2C according to Modification 2 is different from the drying tower 2 according to the above-described embodiment in that the inside of the drying container 10 is virtually partitioned into three drying chambers. Therefore, in the description of the drying tower 2C according to the modified example 2, the same or similar members as those in the above-described embodiment are denoted by the same reference numerals in the drawings, and the redundant description is omitted.

  As shown in FIG. 3, in the drying container 10 of the drying tower 2 </ b> C according to the second modification, two throttle parts 6 are provided at positions separated in the vertical direction. Each throttle portion 6 is provided with a taper forming body 61 as an obstacle 60. The inside of the drying container 10 is virtually divided into three drying chambers (an upper drying chamber 10a, an intermediate drying chamber 10c, and a lower drying chamber 10b) with the outlet 61b of each taper forming body as a boundary. For each drying chamber, a drying gas jet port 16 and an exhaust port 17 are provided. The exhaust ports 17 provided in the intermediate drying chamber 10 c and the lower drying chamber 10 b are arranged so as to open into the gap V formed by the obstacle 60.

  In the drying tower 2C according to the modified example 2 of the above configuration, an object to be dried is input from the top of the drying container 10 and discharged from the bottom of the drying container 10, whereby the upper drying chamber 10a and intermediate drying are performed. A moving layer continuous to the chamber 10c and the lower drying chamber 10b is formed. Then, by independently introducing and discharging the drying gas in each of the drying chambers 10a, 10b, and 10c, the object to be dried and the drying gas are brought into contact with each other.

  Although one intermediate drying chamber 10c is formed in the drying tower 2C according to Modification 2, the number of intermediate drying chambers 10c can be increased. In this case, the drying container 10 is provided with the number of narrowed portions 6 that is obtained by adding 1 to the number of intermediate drying chambers 10 c provided. For example, when the number of intermediate drying chambers 10 c is 2, the drying container 10 is provided with three throttle parts 6. Then, if the upper drying chamber is regarded as the upper drying chamber according to the above-described embodiment and the lower drying chamber is regarded as the lower drying chamber according to the above-described embodiment, the above-described embodiment. A drying container having three or more stages of drying chambers can be configured by repeating the upper drying chamber and the lower drying chamber according to the above in the vertical direction.

DESCRIPTION OF SYMBOLS 1 Drying equipment 2 Drying tower 3 Discharge device 4 Drying gas supply device 5 Input device 6 Restriction part 10 Drying container 10a, 10b Drying chamber 13 Input port 14 Discharge port 16 Drying gas jet 17 Exhaust port 19 Flow path member 46 Flow Road member 60 Obstacle 61 Taper forming body 62 Rod-shaped body

Claims (4)

A tower-shaped drying container in which a material to be dried is input from the top and the material to be dried is discharged from the bottom;
An obstacle provided in the drying container so as to reduce a flow path area of the object to be dried, while preventing a downward movement of the object to be dried while maintaining a laminar flow of the object to be dried, An obstacle that virtually divides the inside of the drying container into an upper drying chamber and a lower drying chamber with an obstacle as a boundary;
A first flow path member provided at a lower portion of each of the upper drying chamber and the lower drying chamber and having a drying gas jet port for ejecting a drying gas;
A second flow path member provided at the upper part of each of the upper drying chamber and the lower drying chamber and having an exhaust port for discharging the drying gas after coming into contact with the object to be dried.
The drying tower in which the exhaust port of the lower drying chamber is open to a gap formed under the obstacle and free of the object to be dried.   The drying tower according to claim 1, wherein the obstacle is a tapered body that decreases a flow path area of the object to be dried downward.   The drying tower according to claim 2, wherein the generating line of the tapered surface of the tapered body and the vertical direction form an angle in a range larger than 0 ° and smaller than 60 °.   The drying tower according to claim 1 or 2, wherein the obstacle is a plurality of rod-like bodies arranged in a direction substantially orthogonal to a moving direction of the object to be dried.

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