JP3660451B2 - Continuous fluid drying method - Google Patents

Description

【００２３】
【発明の効果】
本発明のオーバーフロー排出口とアンダーフロー排出口とが、開閉部材を有する仕切壁を介して接している連続式流動層乾燥装置を使用することにより、乾燥処理終了時の内容物の排出時間を短縮し、流動層乾燥装置の稼働率を高め、生産性を向上させることができる。
【図面の簡単な説明】
【図１】本発明の流動層乾燥装置の一例を示す縦断面概略図
【図２】従来の流動層乾燥装置の一例を示す縦断面概略図
【符号の説明】
１ 流動層乾燥装置
２ 整流板
３ 上部ハウジング
４ 下部ハウジング
５ 排風管
６ 湿潤固体材料入口
７ オーバーフロー排出口
８ アンダーフロー排出口
９ オーバーフロー乾燥品出口
１０ アンダーフロー乾燥品出口
１１ ロータリーバルブ
１２ 中間堰
１３ 出口堰
１４ 開閉部材
１５ 仕切壁[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a continuous fluidized bed drying method capable of quickly discharging the entire content from the apparatus when the drying process of the fluidized bed drying apparatus is completed.
[0002]
[Prior art]
The fluidized bed drying apparatus is a dryer of a type in which wet solids are supplied into a container whose bottom surface is made of a rectifying plate, and a drying process is performed by blowing hot air from below to float and flow the wet solids.
The fluidized bed dryer has a large heat capacity coefficient, a high processing capacity per unit fluidized bed area, and a simple drying chamber structure with few moving parts, making it easy to clean and maintain and easy to use. It is widely used in various industries such as chemical, petrochemical, pharmaceutical, and food.
[0003]
Above all, continuous fluidized bed dryers require less equipment for input and discharge, compared to batch and semi-continuous types, and the operation of the drying system is in a steady state, so operation management is easy. Therefore, it is widely used in industries that require mass processing such as the petrochemical industry.
However, even in a continuous fluidized bed drying apparatus, it is necessary to discharge the entire content when changing or stopping the type of the object to be dried. As the apparatus becomes larger, the time required for this discharge becomes longer. Therefore, in order to improve the operating rate of the drying apparatus, a technique for shortening such time is required.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a continuous fluidized bed drying method capable of quickly discharging the contents at the end of the drying process in order to improve the operating rate of the drying apparatus.
[0005]
[Means for Solving the Problems]
That is, the gist of the present invention, possess an overflow outlet and underflow outlet at and fluidized drying method using a fluidized bed dryer in which they are in contact via a partition wall having an opening and closing member, at the time of steady state , Opening / closing member is closed, drying is performed while discharging dry products from overflow outlet and underflow outlet, and when discharging all amount, opening / closing member is released and all amount is discharged from overflow outlet and underflow outlet In a continuous fluidized drying method.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail. FIG. 1 is a schematic longitudinal sectional view showing an example of a fluidized bed drying apparatus used in the present invention , and FIG. 2 shows an example of a conventional fluidized bed drying apparatus. Hereinafter, the present invention will be described based on these drawings.
[0007]
Configuration of general fluidized bed drying apparatus Generally, the fluidized bed drying apparatus 1 includes an upper housing 3 and a lower housing 4 which are divided by a current plate 2. Although not shown in the drawing, the lower housing 4 is provided with a blower pipe for supplying gas (hot air) into the fluidized bed drying apparatus 1 connected to a blower by piping. The upper housing 3 has a wet solid material inlet 6 for supplying the wet solid material into the fluidized bed drying apparatus 1, an overflow outlet 7 for discharging the solid material dried during steady operation, and a flow on the rectifying plate 2. Discharge of the solid material stagnating at the bottom of the bed and an underflow discharge port 8 for discharging the solid material during unsteady operation such as when washing or stopping, and an exhaust pipe 5 for discharging gas are provided. It is done.
[0008]
Discharge method In the continuous fluidized bed drying apparatus, an outlet weir 13 as shown in FIG. 2 is provided, and during steady operation, the dried solid material mainly overflows this weir while overflowing the discharge outlet. In many cases, the structure is such that the gas is discharged through the air pipe 7.
In addition, the dry solid material stagnating in the lower part of the fluidized bed during steady operation is extracted, the interior of the drying device is washed when changing the type of the object to be dried, and the solids in the device during unsteady operation such as when the device is stopped For the purpose of discharging the entire amount of material, an underflow discharge port 8 having an opening at the lower portion of the outlet weir 13 is used.
[0009]
Partition wall In the fluidized bed drying apparatus of the present invention, an overflow / underflow combined type having an overflow discharge port 7 having an opening at the top of the outlet weir 13 and an underflow discharge port 8 having an opening at the bottom. In addition, the underflow discharge port 8 and the overflow discharge port 7 are in contact with a partition wall 15 having an opening / closing member 14 on the downstream side of the opening of the underflow discharge port 8. It has a structure.
[0010]
When the entire amount of the material remaining in the drying apparatus for cleaning or stopping is discharged, the opening / closing member 14 that is closed during the normal operation is opened. Even when the height of the fluidized bed of solid material becomes lower than the height of the outlet weir 13 during discharge, both the discharge ports are in contact with each other by the partition wall 15 having the opening and closing member 14. The discharge capacity of the overflow dried product outlet 9 can be utilized until almost all of the solid material is discharged from the fluidized bed drying apparatus. Therefore, it is possible to discharge the entire amount in a shorter time than when discharging through the underflow discharge port 8 alone.
[0011]
Opening and closing member As the opening and closing member 14 used in the method of the present invention, a member that can be kept closed during the steady operation of the fluidized bed drying apparatus may be used, for example, a slide gate, a flap gate, a cut gate. Examples thereof include gates such as gates, butterfly valves, sanitary valves, and dampers. Among these, butterfly valves are preferred from the standpoint of difficulty in clogging solid materials, ease of cleaning, and valve capacity.
[0012]
The opening / closing member 14 only needs to have a size that allows the opening when it is in an open state to be transported without clogging with the solid material after drying. Although different depending on the physical properties and the manner of the drying treatment, from the viewpoint of discharging the entire amount in a short time, a size having a transporting capability equivalent to or higher than the discharging capability of the overflow dry product outlet 9 is preferable.
[0013]
The opening / closing member 14 may be installed at a position where the upper end of the opening of the opening / closing member 14 is lower than the upper end of the opening of the underflow discharge port 8. In order to prevent the solid material from remaining, The lower end of the opening of the opening / closing member 14 and the lower end of the opening of the underflow discharge port 8 are preferably installed so as to have substantially the same height.
The lower end of the opening of the underflow discharge port is preferably the same height as the bottom of the fluidized bed on the rectifying plate 2 in consideration of discharge efficiency and prevention of stagnation. It is preferable that the part has the same height as the bottom of the fluidized bed.
[0014]
Rotary valve Generally, a rotary valve is provided at the outlet of the dried product in order to keep the discharge rate of the solid material constant, but like a vinyl chloride polymer produced by a suspension polymerization method, When drying wet solid materials that vary greatly in bulk density and mass supply speed depending on the product type, the moisture content of the product after drying should be controlled to a constant level, or the supply rate to the downstream side of the process should be stabilized. As a purpose, it is preferable to use a rotary valve of a type that can variably control the number of revolutions, and to change the number of revolutions according to the product type.
[0015]
Other ancillary equipment for fluidized bed dryer Other commonly used equipment such as material supply device, air heating device, dust collector, blower, exhaust air filter, etc. attached to fluidized bed dryer The selection may be appropriately made according to the physical property value of the wet solid material to be dried and the required drying treatment capacity.
Further, when drying a polymer having relatively low heat resistance such as a vinyl chloride polymer or an ABS resin, it is also preferable to perform a drying process using a fluidized bed drying apparatus of a type in which a heat transfer tube is installed. It is.
[0016]
Operation method of fluidized bed drying apparatus in steady state The fluidized bed drying apparatus of the present invention described above is the same as a normal fluidized drying apparatus in a state in which the opening / closing member 14 is closed in a continuous drying process in a steady state. You can drive in the same way. For example, the moisture content of the product is controlled while controlling the discharge amount of the dried product through the overflow discharge port 7 and the underflow discharge port 8 by the number of revolutions of the rotary valve 11 installed at the outlets 9 and 10 of the respective dry products. In order to keep the temperature constant, the drying process may be performed by adjusting the temperature inside the apparatus, the supply amount of the wet solid material, the hot air temperature, the flow rate, and the like.
[0017]
Operation method of fluidized bed drying apparatus when discharging the whole amount When discharging the entire amount of the solid material in the fluidized bed drying apparatus of the present invention for cleaning, product type switching, etc., the opening / closing member 14 is opened, The overflow discharge port and the underflow discharge port communicate with each other, and the discharge capacity of both of them is utilized, and within the processing capacity of the downstream piping connected to the overflow dry product outlet 9 and the underflow dry product outlet 10 As long as the heat generated by the rotation of the rotary valve does not adversely affect the product quality, the rotary valve is set at the maximum rotational speed and discharged. As a result, after the powder level is lower than that of the outlet weir 13 in the past, the discharge was performed only through the underflow discharge port 8, but the underflow discharge port and the overflow were discharged until almost the entire amount was discharged. The ability to use the outlet can be utilized, and the time required for discharging can be greatly reduced.
[0018]
【Example】
Next, specific embodiments of the method of the present invention will be described using examples, but the present invention is not limited by the following examples unless it exceeds the gist.
Example A rotary valve having a discharge capacity of 10 tons / hour and 2 tons / hour is connected to an overflow outlet 7 and an underflow outlet 8 as shown in FIG. A continuous multi-chamber fluidized bed drying apparatus having a floor area of 28 m ² and equipped with heat transfer tubes, in which an overflow outlet and an underflow outlet are in contact via a partition wall 15 having
[0019]
Using this, a wet solid obtained by subjecting the vinyl chloride polymer slurry produced by the suspension polymerization method to centrifugal dehydration was dried by closing the opening / closing member 14. At this time, the rotational speed of the rotary valve connected to the overflow outlet 7 is set to 10.5 rpm, the rotational speed of the rotary valve connected to the underflow outlet 8 is set to 8 rpm, and the dried vinyl chloride polymer is extracted. Was performed continuously.
[0020]
After the drying process is completed, both the rotary valve connected to the overflow discharge port 7 and the rotary valve connected to the underflow discharge port 8 are set to 11 rpm, the opening / closing member 14 is opened, and the rotary valve stays in the fluidized bed drying apparatus. The total amount of vinyl chloride polymer (10 tons) was discharged. The time required for discharge is shown in the table.
[0021]
Comparative example Using a fluidized bed drying apparatus (without the opening / closing member 14) shown in Fig. 2, a wet solid of the vinyl chloride polymer was dried under the same conditions as in the example, and then dried. After completion of the treatment, the entire amount of the vinyl chloride polymer staying in the fluidized bed dryer was discharged. The time required for discharge is shown in the table.
[0022]
[Table 1]

[0023]
【The invention's effect】
By using a continuous fluidized bed drying device in which the overflow outlet and the underflow outlet of the present invention are in contact with each other through a partition wall having an opening / closing member, the discharge time of contents at the end of the drying process is shortened. In addition, the operation rate of the fluidized bed drying apparatus can be increased and the productivity can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic vertical sectional view showing an example of a fluidized bed drying apparatus of the present invention. FIG. 2 is a schematic vertical sectional view showing an example of a conventional fluidized bed drying apparatus.
DESCRIPTION OF SYMBOLS 1 Fluidized bed drying apparatus 2 Current plate 3 Upper housing 4 Lower housing 5 Exhaust pipe 6 Wet solid material inlet 7 Overflow outlet 8 Underflow outlet 9 Overflow dried product outlet 10 Underflow dried product outlet 11 Rotary valve 12 Intermediate weir 13 Exit weir 14 Opening and closing member 15 Partition wall

Claims (2)

Possess an overflow outlet and underflow outlet at and fluidized drying method which they are using a fluidized bed dryer in contact via a partition wall having an opening and closing member, at the time of steady state, the opening and closing member and a closed state, Drying is performed while discharging the dried product from the overflow outlet and underflow outlet, and when the total amount is discharged, the open / close member is released and the entire amount is discharged from the overflow outlet and underflow outlet. Fluid drying method. The continuous fluidized drying method of the vinyl chloride polymer according to claim 1.

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