JPH0716952B2 - Vertical 2-stage fluid dryer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vertical two-stage fluidized dryer suitable for drying a powdery polymer.

(Prior Art) As shown in FIG. 2 to be described later, a conventional vertical two-stage fluidized dryer has a perforated plate reversal bed 15 at the lower portions of the upper fluidized drying chamber 2 and the lower fluidized drying chamber 3, respectively. 16 is provided, and the material to be dried supplied from the upper part 1 of the upper fluidized-bed drying chamber 2 is flowed and dried in the upper fluidized-bed drying chamber 2 by hot air from the lower part for a certain period of time, and then the reversal bed 15 is inverted. Then, it is dropped into the lower-stage fluidized-drying chamber 3, where it is flowed and dried for a certain period of time, and then the reversal bed 16 is reversed and dropped into the hopper 4, and taken out from the dryer via the rotary valve 14.

On the other hand, the air for flowing and drying the material to be dried is heated by the heater 9 and passes through the perforated plate of the lower reversal bed 16 to flow the material to be dried, and then passes through the perforated plate of the upper reversal bed 15. The material to be dried is made to flow, and cyclone 7 is fed from the top of the dryer tower.
Also, the structure is such that it is discharged to the outside of the device by the exhaust blower 17 via the multi-clone 8.

(Problems to be Solved by the Invention) In such a conventional two-stage fluidized dryer, when a dried product dropped in the hopper 4 is shelved in the hopper 4 and cannot be taken out of the device. There are problems
Further, the hot air heated by the heater 9 at a temperature of 70 to 125 ° C. comes into direct contact with the dried product in the hopper 4, so that the dried product is abnormally heated, and the dried product is colored or scorched to deteriorate the quality. If you do, it has problems. Also, when the reversing beds 15 and 16 are reversed, the amount of air in the fluidized drying chambers 2 and 3 suddenly fluctuates, the temperature in the fluidized drying chambers 2 and 3 is not constant, and uniform drying is not possible. I also have.

The present inventors have diligently studied to solve the above-mentioned problems of the conventional two-stage fluidized dryer. As a result, as illustrated in FIG. 1 to be described later, the inversion beds 15 and 16 are changed to fixed beds 5 and 6 which can be inverted, and the material to be dried is transferred to the next step by the upper fluidized drying chamber 2 and the lower fluidized drying. It was found that a dryer designed to run through the overflow zones 10 and 11 provided in the chamber 3 and the rotary valves 12 and 13 connected to the overflow zones can solve the above-mentioned problems, and the present invention was completed based on this finding. .

As is clear from the above description, an object of the present invention is to prevent defective discharge of the dried product in the hopper 4 due to shelving of the dried product, and to prevent deterioration of the dried product due to hot air. The temperature in 3 and the flow of the material to be dried can be made uniform, and uniform drying can be performed. When the inside of the dryer is emptied, the fixed beds 5 and 6 are inverted to empty the inside of the dryer in a short time. The present invention is to provide a vertical type two-stage fluidized dryer.

(Means for Solving the Problems) The present invention has the following configurations.

In the vertical two-stage fluidized dryer, rotary valves are provided in the overflow zone and the piping section connected to the overflowed fluid in the upper fluidized drying chamber and the lower fluidized drying chamber, respectively, and each fixed bed of the upper and lower dryers can be inverted. The vertical two-stage fluidized dryer characterized in that

In the vertical two-stage fluidized dryer of the present invention, the inversion beds 15, 16 of the conventional vertical two-stage fluidized dryer are changed to reversible fixed beds 5, 6 and, as shown in FIG. 1 described later, The upper fluidized drying chamber 2 and the lower fluidized drying chamber 3 are provided with overflow zones 10 and 11 for taking out a substance to be dried, that is, contents, and rotary valves 12 and 13 for transferring the taken out contents to the next step. There is. The upper and lower overflow zones must be provided on opposite sides, and the height of the overflow forming the overflow zone (the height above the fixed beds 5 and 6) is not particularly limited, but the retention time of the contents And the amount of the material to be dried (dry amount) to be supplied. Further, the height may be a fixed system in which the height is fixed to a fixed height, but it may be a slide system in which the height can be arbitrarily changed. It is necessary to provide a rotary valve in the pipe section connected to the overflow zone. The purpose of providing the rotary valve is to block the hot air rising from the lower part and to transfer the contents overflowing from the overflow port to the next step. Also, when emptying the dryer due to product type switching, etc., the fixed bed 5,
The structure is such that 6 can be reversed to empty the inside of the container in a short time.

Next, the operating condition of the vertical two-stage fluidized-bed dryer of the present invention will be described with reference to FIG.

The cake-like substance to be dried containing water is supplied into the upper fluidized-drying chamber 2 through a supply port 1 provided at the upper part of the upper fluidized-drying chamber 2, and is fluidized and dried by hot air passing through the fixed bed 5. Then, it is gradually led to the overflow zone 10. The material to be dried guided to the overflow zone 10 is supplied to the lower fluidized-bed drying chamber 3 by the rotary valve 12 and fluidized by the hot air passing through the fixed bed 6,
Further dried and led to the overflow zone 11,
It becomes a dried product. The dried material guided to the overflow zone 11 is transferred to the next step by the rotary valve 13. Air for flowing and drying the material to be dried is
Blower blows through heater 9 and heater 9
The air heated by the above, that is, hot air, passes through the lower fixed bed 6 to flow and dry the material to be dried and rises while passing through the fixed bed 5, where it is also flowed and dried, and at the same time, the cyclone 7, by the top of the dryer tower, It is discharged from the blower 17 to the outside of the device via the multi-clone 8.

(Example) Next, an example using the vertical two-stage dryer of the present invention will be described.

Example 1 A powdery vinyl chloride polymer in the form of a cake containing 1 to 5% by weight of water was supplied at a rate of 2 T / Hr from the supply port 1 of the dryer of the present invention illustrated in FIG. It is made to flow and dry by the hot air that has passed through the floor 5, and is supplied from the overflow zone 10 to the lower flow drying chamber 3 via the rotary valve 12. In the lower fluidization drying room 3, the same flow,
After drying, the dried product was extracted from the overflow zone 11 via the rotary valve 13. The water content of the extracted dried product was 0.01 to 0.10% by weight. This drying operation was continuously performed for 10 hours. At this time, the hot air temperature in the hopper 4 was 80 ° C., and the air volume was 7,000 Nm ³ / Hr.

The fine powdery polymer entrained in the hot air was supplemented by the cyclone 7 and the multi-clon 8, and the supplemented polymer was supplied to the lower fluidized-drying chamber 3 by the rotary valves A and B. At this time, since the amount of hot air supplied is kept constant during the drying, the cyclone 7 and the multi-clon 8
The amount of fine powdery polymer to be supplemented with is also kept constant,
As a result, the amount of the fine powder polymer supplied from the rotary valves A and B to the lower fluidized-bed drying chamber 3 is also made constant, the temperature and fluidized state in the lower fluidized-bed drying chamber 3 are always stable, and stable drying operation is continued. We were able to. Further, since the dried polymer discharged from the lower fluidized drying chamber 3 did not stay in the hopper 4, heating of the dried polymer by the hot air introduced into the hopper 4 was avoided, and the polymer was not colored or scorched. No occurrence was seen.

Comparative Example 1 Using a two-stage fluidized dryer as illustrated in Fig. 2, a cake-shaped vinyl chloride polymer containing 1 to 5% by weight of water was continuously dried for 10 hours. Supply port 1 to 2T / Hr
Then, the above-mentioned cake-shaped vinyl chloride polymer is supplied to the upper fluidized-bed drying chamber 2 and allowed to flow and dry for a certain period of time (7 minutes), and then the upper reversal bed 15 is inverted, and the polymer in the upper fluidized-bed drying chamber 2 is transferred to the lower fluidized-bed drying chamber It was dropped to 3 and fluidized and dried for a certain period of time. After a certain period of time, the lower inverting bed 16 was turned over, the polymer in the lower fluidized drying chamber 3 was dropped onto the hopper 4, and then taken out of the dryer via the rotary valve 14.
When the inversion bed 15 or 16 is inverted, the amount of hot air in the upper and lower fluidized drying chambers increases instantaneously by about 20%, and as a result, the amount of polymer entrained in the cyclone 7 and multi-clone 8 rapidly increases. Then cyclone 7, multi-clon 8
Polymer shelving occurred. For this reason, the temperatures of the upper and lower fluidized drying chambers rapidly rise, and the polymer dropped in the hopper 4 is too dry,
Static electricity was stored in the hopper 4 and shelving occurred. Further, it was observed that the polymer heated in the hopper 4 was colored or burnt. Further, in order to remove the polymer shelved in the cyclone 7 and the multi-clone 8, the cyclone and multi-clone were hammered from the outside with a hammer, and a large amount of the shelved polymer was transferred to the lower flow drying chamber 3 at a time. Since it dropped, the temperature in the lower fluidized drying chamber drastically dropped, and as a result, when the polymer containing a large amount of water (1-2% by weight) was discharged without being sufficiently dried, a phenomenon was sometimes observed. I couldn't drive stably during the hours of operation.

(Effects of the Invention) When the two-stage fluidized dryer of the present invention is used, there is no fluctuation in the air volume when the reversing bed is inverted, unlike the conventional two-stage fluidized dryer, so that a constant fluidized state is always maintained during drying. As a result, the temperatures of the upper and lower fluidized drying chambers are also stabilized, and stable drying operation is possible. In addition, it does not cause shelving with cyclones or multi-clones. Moreover, since the discharged polymer does not fall into the hopper, the polymer is not adversely affected by heat.

As described above, when the two-stage fluidized dryer of the present invention is used, stable drying operation is possible, and since the dried product does not stay in the hopper 4, heating of the dried product by hot air is avoided, Deteriorated quality of dried products (coloring and burning)
Therefore, it can be suitably used for drying various powdery substances such as powdery polymers, and when the dryer is emptied due to product type change, etc., it can be shortened by inverting the fixed bed. Since the inside of the container can be emptied in time, operations such as product type switching can be performed in a short time, and it is possible to prevent the deterioration of the quality of the subsequent resin due to the mixing of the preceding resin. It can be suitably used as a dryer for drying.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a two-stage fluidized dryer of the present invention, and FIG. 2 is a schematic diagram of a conventional two-stage fluidized dryer. In the figure, 1: Supply port to the upper stage, 2: Upper fluidized drying chamber 3: Lower fluidized drying chamber, 4: Hopper 5: Upper fixed bed, 6: Lower fixed bed 7: Cyclone, 8: Multiclone 9: Heater 10 : Upper overflow zone 11: Lower overflow zone 12: Upper rotary valve 13: Lower rotary valve 14: Discharge rotary valve 15: Upper reverse bed, 16: Lower reverse bed 17: Blower A: Cyclone rotary valve B: Multi-clon rotary valve Represent.

Claims (1)

[Claims] 1. A vertical two-stage fluidized-bed dryer, wherein rotary valves are provided in overflow zones and pipe sections connected thereto in the upper-staged fluidized-drying chamber and the lower-staged fluidized-drying chamber, and fixed beds in the upper and lower-staged drying chambers. A vertical two-stage fluidized dryer characterized by being able to reverse.