JP2937932B2 - Fluidized bed drying / cooling method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for drying and cooling wet materials such as slag, pulverized coal, sludge and the like using a fluidized bed.

[0002]

2. Description of the Related Art A drying process using a fluidized bed has a high drying efficiency, such as a high drying rate. Therefore, a fluidized bed dryer is used for drying various wet raw materials. On the other hand, since the mixed state is good in the fluidized bed, the residence time of the object to be dried tends to be non-uniform, and it is difficult to make the degree of drying of the object to be dried uniform. Therefore, as described in Japanese Utility Model Laid-Open Publication No. 2-48785, a flow chamber provided with a fluidized bed is divided into a plurality of chambers by a partition plate so that a gap is formed between the flow chamber and the dispersion plate. A barrier plate parallel to the partition plate is provided on the downstream side of
There is known a technique in which a gas is ejected upward between a partition plate and a weir plate to make the residence time and the degree of dryness of an object to be dried uniform.

[0003]

When a wet raw material such as slag, pulverized coal, sludge or the like is dried in a fluidized bed, the temperature of the discharged dried product is generally as high as about 50 to 80 ° C. Therefore, in the process of treating the dried product, the residual moisture of the dried product evaporates, and phenomena such as dust generation and dust adhesion due to fine powder occur, which is not preferable in operation. In particular, dust generation due to fine powder leads to deterioration of the environment, and if dust adheres to an enclosed space or the like in the apparatus, not only cleaning becomes difficult but also a trouble of the apparatus may be caused.

[0004] Therefore, after drying in a fluidized bed, it is common practice to cool the dried product using another cooler.
There is a problem that the equipment becomes complicated and the driving operation becomes complicated. There is also known a technique in which the drying process using a fluidized bed is divided into two stages, and the drying process is further performed using a fluidized bed dryer of another type after the fluidized bed is dried. There is a problem that it becomes complicated.

In the technique described in Japanese Unexamined Utility Model Publication No. 2-48785, if the particles to be dried have the same particle diameter, the residence time and the degree of drying can be made uniform to some extent, but the particle diameter can be wide. In the case of treating a dried material having a distribution, there is a problem that large-diameter particles are deposited at a lower portion of the partition plate and cannot be discharged downstream.

The present invention has been made in view of the above points, and an object of the present invention is to separate a chamber having a fluidized bed into a drying chamber and a cooling chamber when drying and cooling a wet raw material using the fluidized bed. By doing so, it is possible to discharge the wet raw material as a dry product of a predetermined moisture and temperature with a compact facility,
It is an object of the present invention to provide a method and an apparatus that can easily handle a dried product, can prevent dust and dust from adhering due to evaporation of residual moisture, and can perform drying and cooling with a minimum amount of hot air and cooling air. .

[0007]

In order to achieve the above-mentioned object, a fluidized bed drying / cooling method according to the present invention is characterized in that a chamber provided with a fluidized bed is separated by a vertical partition member into an upstream drying chamber and a downstream drying chamber. Divided into two chambers with a cooling chamber, and opened under or below the partition member
A communication passage with a variable area is formed, a wet raw material is introduced into a drying chamber, hot air is introduced and fluidized and dried, and the communication passage is formed.
Dry matter moving from the drying chamber to the cooling chamber by changing the opening area of the
The dried material is moved to the cooling chamber through the communication passage so that the flow rate can be adjusted, and cooling air is introduced into the cooling chamber to cool the dried material, and the exhaust gas from the drying chamber is separated into solid-gas separation equipment.
To separate the fines and return the separated fines to the cooling chamber.
It is characterized in that to (see FIG. 1, FIGS. 2-9).

[0008] In the above method Symbol of the invention, 90% to 100% humidity in the room in the drying chamber and the cooling chamber, preferably at approximately 100% (95% to 100%), the dryness and the cooling temperature to a target It is desirable to adjust the amount of hot air and the amount of cooling air so as to be as shown in FIG. in this way,
The humidity (fluidized bed humidity) in the drying chamber and the cooling chamber is desirably substantially 100%, and specifically, desirably 95% or more. In this case, the lower limit is set for the amount of hot air and the amount of cooling air in order to maintain the fluidized state of the fluidized bed, and is adjusted so as not to be lower than the lower limit.

[0009] Also, in the method of the present invention, by introducing the exhaust gas from the cooling chamber to the solid-gas separator to separate the fines, as a dry-cooling of the fines, are discharged from the fluidized bed of the cooling chamber It is desirable to collect it separately from the dried and cooled coarse particles (see FIG. 1). In the method of the present invention, the gas is introduced into the drying chamber such that the exhaust gas humidity at the inlet of the solid-gas separation device connected to the drying chamber outlet is in the range of 80 to 90% at which dew condensation does not occur in the exhaust gas system. It is desirable to introduce a part of the hot air near the upper part of the drying chamber (see FIG. 1). If the exhaust gas humidity is higher than the above range, there is a disadvantage that dew condensation occurs in the exhaust gas system.

In the fluidized bed drying / cooling apparatus of the present invention, a chamber provided with a fluidized bed above a wind box via a gas dispersion plate is a vertical partition member, and an opening area is variable below or below the partition member.
As communication passage is formed, a partition into two chambers of the drying chamber and the downstream cooling chamber on the upstream side, and connect the wet feedstock input means into the fluidized bed of the drying chamber, hot air introduced into the wind box of the drying chamber Connect the pipe, connect the drying / cooled material discharge means to the fluidized bed in the cooling chamber,
Connect the cooling air supply pipe to the air box of the cooling room, and
Connect a gas-solid separator to the gas outlet, and
It is characterized in that the lower part and the cooling chamber are connected via a dry fine powder extraction pipe (see FIG. 1). In the above-described apparatus of the present invention, the communication passage can be constituted by a vertically movable gate (see FIGS. 2 to 4). Further, the communication passage can be formed of a number of horizontal or inclined short tubes (see FIGS. 5 to 7). Further, the communication passage can be constituted by a rotatable plate-like body (see FIGS. 8 and 9). Of course, other configurations can be adopted as long as the opening area of the communication passage is variable.

[0011] Also, in the apparatus of the present invention, it is desirable to connect the solid-gas separation device to the exhaust gas outlet of the cooling chamber, connecting the drying and cooling thereof fines discharge pipe at the bottom of the solid-gas separation device (See FIG. 1). Further, in these apparatuses of the present invention, the hot air introduction pipe to be introduced into the wind box of the drying room is branched so that trouble due to dew condensation does not occur in the exhaust gas system.
, It is desirable to connect the branch hot air pipe to the exhaust gas pipe of the upper or drying chamber outlet of the drying chamber (see FIG. 1). In addition,
Examples of the solid-gas separation device include a cyclone and a bag filter.

[0012]

Embodiments of the present invention will be described below in detail. 1 to 4 show a first embodiment of the present invention.
1 shows a fluidized bed drying / cooling device according to an embodiment. In the present embodiment, the communication passage is constituted by a vertically movable gate, and the opening area of the communication passage is made variable. FIG. 1 shows only a simplified communication passage.
As shown in FIG. 1, a chamber provided with a fluidized bed is vertically partitioned into two chambers by a partition plate 10 serving as a partition member, and a drying chamber 12 is formed on an upstream side and a cooling chamber 14 is formed on a downstream side. On the upstream side of the fluidized bed 16 of the drying chamber 12, a wet raw material introduction pipe 18 for supplying a wet raw material is connected, and on the downstream side of the fluidized bed 20 of the cooling chamber 14, a drying / drying body for discharging a dried / cooled material -The coolant discharge pipe 22 is connected. A communication passage 26 having a variable opening area is formed below the partition plate 10 between the partition plate 10 and the gas distribution plate 24, and details thereof will be described later.

Hot air is introduced into a wind box 28 of the drying chamber 12 from a blower (blower) 30 through a hot air introduction pipe 32.
With this hot air, the fluidized bed 16 is fluidized,
The charged wet raw material is dried. In addition, cooling air is supplied to a wind box 34 of the cooling chamber 14 from a blower (blower) 36 through a cooling air supply pipe 38, and the cooling air fluidizes the fluidized bed 20. Among the dried products that have been fluidized-bed dried in the drying chamber 12, those that have moved through the communication passage 26 are cooled. In FIG. 1, two wind boxes 28 and one wind box 34 are provided, but other numbers can be used. 40,
42 and 44 are control valves, and 46 and 48 are valves. The fluidized medium of the fluidized beds 16 and 20 is a raw material.

Exhaust gas containing fine powder generated by performing fluidized bed drying in the drying chamber 12 is passed through an exhaust gas outlet 50 via an exhaust gas pipe 52 to a solid-gas separation device such as a cyclone 5.
4 and collected by the cyclone 54, is returned to the cooling chamber 14 through the dry powder extraction pipe 56. Exhaust gas containing fine powder generated by performing fluidized-bed cooling in the cooling chamber 14 is supplied from an exhaust gas outlet 58 through an exhaust gas pipe 60 to a solid-gas separation device such as a cyclone 62.
The dried / cooled material fine powder collected by the cyclone 62 is extracted from the dried / cooled material fine powder extraction pipe 64. In addition, a bag filter, another dust collector, or the like can be used as the solid-gas separation device. 66 and 68 are exhaust gas discharge pipes. Further, a branch hot air pipe 70 formed by branching the hot air introduction pipe 32 is connected to the upper part of the drying chamber 12 so that a part of the hot air can be introduced into the upper part of the drying chamber 12. In addition, as shown by the broken line in FIG. 72 and 74 are control valves.

Next, the communication path 26 constituted by a vertically movable gate will be described in detail with reference to FIGS. As shown in FIG. 2, a gate 76 is provided at a lower portion of the partition plate 10, and by adjusting a gap C formed between the partition plate 10 and the gas distribution plate 24, the communication passage 26 is formed.
Can be arbitrarily changed. FIG. 3 shows a case in which a plurality of gates 76 are provided in the communication passage 26. In addition, a configuration in which one gate 76 is provided in the entire communication passage 26 is also possible. As an example of the means for adjusting the gap C, as shown in FIG. 4, a long hole 78 is provided above the gate 76, a bolt 80 is fitted into a predetermined position of the long hole 78, and the gate is positioned at a predetermined position. Means for fixing 76 to the partition plate 10 and the like can be given. It is necessary to adjust the gap C so that the opening area does not cause so-called back mixing.

Next, the steps of drying and cooling the wet raw material by the apparatus according to the present embodiment will be described, taking as an example the case of granulated slag having a water content of 12 to 13%. The granulated slag having a water content of 12 to 13% charged into the drying chamber 12 is dried while flowing in the fluidized bed 16 into which hot air of 250 to 300 ° C. is introduced, and the dried product passes through the communication passage 26. To the cooling chamber 14. The temperature in the drying chamber 12 is 5
Since the temperature of the dried product is from 0 to 80 ° C. and the temperature of the dried product before moving to the cooling chamber 14 is also 50 to 80 ° C., it is necessary to cool the dried product to a predetermined temperature in order to avoid a problem due to evaporation of residual moisture. There is. The dried material moved to the cooling chamber 14 is cooled while flowing in the fluidized bed 20 into which the cooling air at room temperature (about 20 ° C.) is introduced, and is discharged after reaching the target drying degree and cooling temperature. . The water content of the discharged granulated slag is 5 to 6%, the temperature is cooled to 30 to 40 ° C, handling is easy, and it can be used as a raw material for slag cement and the like. In the above steps, the amount of hot air and the cooling air are set so that the humidity (fluidized bed humidity) in the drying chamber 12 and the cooling chamber 14 becomes almost 100% and the target drying degree and cooling temperature as described above. The amount of air for use is adjusted, and the opening area of the communication passage 26 is also adjusted.

The fine powder scattered in the drying chamber 12 is collected by the cyclone 54, returned to the cooling chamber 14, and
The fine powder scattered in the cooling chamber 14 is collected by the cyclone 62 and collected as a dried and cooled material of the fine powder.
Processing can be performed separately from the dried and cooled material of the coarse particles discharged from step 4, and handling at the subsequent stage becomes easy. In addition, drying room 1
2, if the exhaust gas having a humidity of almost 100% and a temperature of 50 to 80 ° C. is discharged as it is, the exhaust gas may be cooled by an exhaust gas system to cause dew condensation. Is introduced into the upper part of the drying chamber 12, and the exhaust gas humidity is adjusted to 80 to 90%, whereby the trouble due to dew condensation can be prevented. Further, if the air volume of the cooling air is adjusted in the cooling chamber 14, the dried / cooled material of the coarse particles discharged from the cooling chamber 14 and the dried / cooled material of the fine powder collected by the cyclone 62 are separated by a predetermined amount. It is possible to divide by classification particle size.

Although the exhaust gas from the drying chamber and the exhaust gas from the cooling chamber may be separately treated and recovered, it is also possible to combine the two exhaust gases for treatment. in this case,
Since the temperature of the exhaust gas from the cooling chamber is low, and condensed with the exhaust gas from the drying chamber, condensation may occur due to cooling. Therefore, the amount of hot air bypass is adjusted so that the humidity of the exhaust gas from the combined air becomes 80 to 90%. When both exhaust gases are treated separately, the amount of hot air bypass is adjusted so that the humidity of each exhaust gas is 80 to 90%. Further, when the moisture content of the wet raw material to be charged is high, the drying chamber may be partitioned into two or three chambers. In this case, the same partition member and communication passage as in the present embodiment are provided. In addition, the number of partitioned rooms is configured to be smaller than or equal to the number of wind boxes.

FIGS. 1 and 5 to 7 show a fluidized bed drying / cooling apparatus according to a second embodiment of the present invention. In this embodiment, instead of the vertically movable gate in the first embodiment, the communication passage is made up of a number of horizontal or inclined short pipes (for example, pipes) and the opening area of the communication passage is made variable. is there. As shown in FIGS. 5 and 6, a plurality of pipes 82 are provided substantially horizontally below the partition plate 10. As shown in FIG. 7, the pipe 82 can be configured to have a slope, or can have any length and thickness. Further, a damper or the like may be provided inside the pipe 82 to make the opening area variable. When an inclined tube is used, it is preferable that the fluidized bed 16 side of the drying chamber be on the top in order to facilitate movement of the dried product. Other configurations, operations, and the like are the same as those in the first embodiment of the present invention.

FIGS. 1, 8 and 9 show a fluidized bed drying / cooling apparatus according to a third embodiment of the present invention. In the present embodiment, instead of the vertically movable gate in the first embodiment, the communication passage is constituted by a rotatable plate-like body, and the opening area of the communication passage is made variable. FIG.
As shown in FIG. 9, a plate-like body 84 is rotatably attached to the lower part of the partition plate 10 via an attachment shaft 86. As shown in FIG. The opening 88 can be changed from outside by adjusting the angle of the plate 84 by rotating the plate 84 by a handle 88 connected and provided outside the apparatus. FIG. 9 shows a case where one plate 84 is provided. However, two plates 84 are provided so that the plate 84 can be adjusted from both sides of the apparatus. A configuration in which three or more sheets are provided is also possible. Other configurations, operations, and the like are the same as those in the first embodiment of the present invention.

[0021]

As described above, the present invention has the following effects. (1) Since the dried product can be discharged at a predetermined moisture and temperature with a compact facility, it is easy to handle the dried product, and it is possible to prevent dust and adhesion of dust due to evaporation of the residual moisture. it can. (2) Since drying and cooling can be performed with the minimum amount of hot air and cooling air, the equipment can be downsized and a blower (blower)
Running costs such as power can be minimized, and the installation space can be reduced. (3) When a part of the hot air introduced into the drying chamber is introduced near the upper part of the drying chamber, dew condensation in the exhaust gas system can be effectively prevented, and troubles such as dust adhesion and corrosion hardly occur. (4) When the fine powder is separated from the exhaust gas in the cooling chamber, the separated fine powder can be processed separately from the coarse particles obtained in the cooling chamber, so that the subsequent handling becomes easy. (5) When fine powder is separated from the exhaust gas in the cooling chamber, if the air volume of the cooling air introduced into the cooling chamber is adjusted, the classified particle diameter can be adjusted to separate the fine powder and the coarse powder.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a fluidized bed drying / cooling apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged vertical cross-sectional view showing an example around a communication passage in the device according to the first embodiment of the present invention.

FIG. 3 is a right side view schematically showing a periphery of a communication passage shown in FIG. 2;

FIG. 4 is an enlarged view showing an example of a gap adjusting means in FIG. 3;

FIG. 5 is an enlarged longitudinal sectional view showing an example around a communication passage in a device according to a second embodiment of the present invention.

FIG. 6 is a right side view showing an outline around a communication passage shown in FIG. 5;

FIG. 7 is an enlarged longitudinal sectional view showing another example around the communication passage in the device according to the second embodiment of the present invention.

FIG. 8 is an enlarged vertical sectional view showing an example around a communication passage in a device according to a third embodiment of the present invention.

FIG. 9 is a right side view schematically showing the periphery of a communication passage shown in FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Partition plate 12 Drying room 14 Cooling room 16 and 20 Fluidized bed 18 Wet raw material introduction tube 22 Drying / cooling material discharge tube 24 Gas dispersion plate 26 Communication passage 28, 34 Wind box 30, 36 Blower (blower) 32 Hot air introduction tube 38 Cooling air supply pipe 40, 42, 44, 72, 74 Control valve 46, 48 Valve 50, 58 Exhaust gas outlet 52, 60 Exhaust gas pipe 54, 62 Cyclone 56 Dry fine powder extraction pipe 64 Dry / cooled substance fine powder extraction pipe 66 , 68 Exhaust gas exhaust pipe 70 Branch hot air pipe 76 Gate 78 Slot hole 80 Bolt 82 Pipe 84 Plate body 86 Mounting shaft 88 Handle C Clearance

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho 58-119193 (JP, U) Japanese Utility Model Sho 52-154769 (JP, U) Japanese Utility Model Sho 42-3577 (JP, Y1) (58) Field (Int.Cl. ⁶ , DB name) F26B 17/04-17/10 F26B 3/02

Claims (10)

(57) [Claims] 1. A chamber having a fluidized bed is divided by a vertical partition member into two chambers: an upstream drying chamber and a downstream cooling chamber, and a communication passage having a variable opening area below or below the partition member. Is formed, the wet raw material is put into the drying chamber, hot air is introduced and fluidized and dried, and the drying area is changed by changing the opening area of the communication passage.
To control the flow rate of dry matter moving from
Then, the dried product is moved to the cooling chamber through the communication passage, and cooling air is introduced into the cooling chamber to cool the dried product, and the dried product is dried.
Exhaust gas from the chamber is introduced into the solid-gas separator to separate fine powder
And returning the separated fine powder to a cooling chamber . 2. A drying chamber and the cooling chamber, according to claim 1 indoor humidity adjusting with 90% to 100%, the dryness and hot air amount so that the cooling temperature and the cooling air amount to the target
The fluidized-bed drying / cooling method described in the above . 3. An exhaust gas from a cooling chamber is introduced into a solid-gas separation device to separate fine powder, and is separated from a dried / cooled coarse particle discharged from a fluidized bed of the cooling chamber as a dried / cooled product of the fine powder. The fluidized bed drying / cooling method according to claim 1 or 2 , wherein the fluidized bed is recovered. 4. The exhaust gas humidity at the inlet of the solid-gas separation device connected to the outlet of the drying chamber is 80 to 80% at which dew condensation does not occur in the exhaust gas system.
4. The method for drying and cooling a fluidized bed according to claim 1, wherein a part of the hot air introduced into the drying chamber is introduced near the upper part of the drying chamber so as to be in a range of 90%. 5. A chamber provided with a fluidized bed above a wind box via a gas dispersion plate is partitioned into two chambers, a drying chamber on the upstream side and a cooling chamber on the downstream side, by a vertical partition member. A communication passage with a variable opening area is formed on the side or lower part, a wet raw material charging means is connected to the fluidized bed in the drying chamber, a hot air introduction pipe is connected to a wind box in the drying chamber, connect the cooled product discharging means, connected to the cooling air supply pipe to the windbox of the cooling chamber, connecting the solid-gas separation device to the exhaust gas outlet of the drying chamber, the gas-solid
The lower part of the separation device and the cooling chamber are connected via a dry powder extraction pipe.
A fluidized bed drying / cooling apparatus characterized by being continued . 6. The fluidized bed drying / cooling apparatus according to claim 5, wherein the communication path is constituted by a vertically movable gate. 7. The fluidized bed drying / cooling apparatus according to claim 5, wherein the communication passage is formed by a number of horizontal or inclined short pipes. 8. The fluidized-bed drying / cooling apparatus according to claim 5, wherein the communication passage is constituted by a rotatable plate . 9. The solid-gas separation device is connected to the exhaust gas outlet of the cooling chamber, according to any one of claims 5-8 for drying and cooling was pulverized extraction pipe is connected to the lower portion of the solid-gas separation device Fluidized bed drying and cooling equipment. 10. A hot air introduction pipe to be introduced into a wind box of a drying room is branched to prevent a trouble due to dew condensation in an exhaust gas system.
The fluidized-bed drying / cooling apparatus according to any one of claims 5 to 9 , wherein the branch hot air pipe is connected to an upper part of a drying chamber or an exhaust gas pipe at an outlet of the drying chamber.