SU1153209A2 - Arrangement for drying solutions in fluidized bed - Google Patents

Abstract

INSTALLATION FOR DRYING OF SOLUTIONS IN A PSEED-LIQUE LAYER at author. St. № 924473, different from the fact that, in order to intensify the process and. improving the quality of drying, between the agitator and the nozzles, there is additionally installed a perforated scraper, completed on the involute of the same circumference and the same direction of unwinding, as the involute of the nozzles installation, rotated relative to the last 60-90 in the direction opposite to the direction of unwinding of the volunteers the end of the scraper is connected to the discharge opening.

Description

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Fi-g 1 The invention relates to a technique for drying solutions, mainly sorbitol, and can be used in the chemical, medical and other industrial sectors. According to the main author. St. No. 924474 is a well-known installation for drying solutions in a fluidized bed, predominantly cop6HTaj containing a drying chamber with a gas distribution system and a discharge opening, located above the grate at the same distance from one another and the rotary paddle mixer, while over the grid there is a curve. the diameter of which is equal to O, 1-0,14 of the chamber diameter, and the end of the evolvent is located on a radius that is 10–20 from the discharge hole axis O 10-20 along the agitator, the blades of which are angled lO-lS to the gas distribution grid l. However, in this installation, there is no control over the granulometric composition of the product being removed, there is a large amount of fine particles in the material being discharged, while part of the large particles remain in the fluidized bed. As a result, the intensity of the drying process is reduced and the quality of the finished product deteriorates. The aim of the invention is to intensify the process and increase the quality of drying. The goal is achieved by the fact that in the installation for drying the solutions in the fluidized bed meizda the perforated scraper additionally installed along the involute of the same circle and the same direction of unwinding of the injector of the nozzles installation turned to 6090 V in the same circle and additionally installed the direction opposite to the unwinding direction of the involute, and the end of the scraper is connected to the discharge opening. On (jMr. 1 shows a plant for drying solutions in the fluidized bed; in Fig. 2 - section A-A in Fig. I; in Fig. 3 - section B-B in (jMr. 2; in Fig. 4 - section B - B in Fig. 2. The installation contains a drying chamber 1, in the lower part of which a fluidized bed 3 of the product being dried is placed on the gas distribution grid 2. A mixer 4 and a perforated scraper 5 are installed above the gas distribution grid 2 above the boiling bed 3 at a height of 400 500 mm from the gas distribution grid 2 installed nozzles 6, connected to the supply line solution 7. In the lateral station At the level of the fluidized bed there is a discharge opening 8. The nozzles 6 are set along an involute circle with a diameter equal to 0.1-0.14 diameters of the chamber, and the end of this involute is located on a radius 10-20 inches from the axis of the discharge opening. the rotation of the agitator, the blades of which are at an angle of 10-15 to the gas distribution grid 2. The perforated scraper 5 is made along an involute of the same circumference and the same direction of unwinding as the nozzle of the installation of the nozzles 6 rotated relative to last at 60-90 in the opposite direction to the unwinding of the involutes. The end of the scraper 5 is connected to the discharge opening 8. The installation works as follows. In the drying chamber 1 on the gas distribution grid 2 poured a layer of dry product, such as granules or sorbitol crystals, with a height of 150-200 mm. From the bottom, through the gas distribution grid 2, sufficient air is supplied to the drying chamber 1 in an amount sufficient to form the fluidized bed 3. The agitator 4 is turned on, by means of which the rotational motion and more intensive mixing of the granules are given to the fluidized bed. When the desired temperature of the fluidized bed 3 (for sorbitol, about 60 ° C) is reached, the solution 7 is fed through the nozzles 6 into the fluidized bed 3. The sprayed solution is deposited on the granules and dried. The dry granulated product is sieved with a perforated scraper 5 and the larger granules of the required size are removed from the drying chamber through unloading.

HOC hole 8. During operation, the height of the fluidized bed 3 is kept constant. The perforated scraper 5 also contributes to the stabilization of its particle size distribution. The exhaust gas is discharged from the drying chamber 1 through a nozzle at the top of the chamber.

 It is expedient to use this setting. For drying highly concentrated solutions, for example, sorbitol, the solids content is more than 70%. To dry these solutions, the required amount of coolant is relatively small and the flow rate of the fluidized air is determined by the conditions of the fluidization rather than drying. In this case, it is economically advantageous to conduct drying at low fluidization rates, however, by using a rotary mixer, to ensure a high mixing intensity of the granules in the bed. In addition, the fluidized bed rotates, the abrasion and crushing of the granules in the bed are ensured with the help of a mixer. The latter is extremely important to ensure the formation of fine particles in the layer, which serve as centers for the formation and growth of new granules. In addition, the removal of only larger granules from the layer contributes to the stabilization of the granulometric composition of the fluidized bed, which in turn makes it possible to intensify the drying process and to obtain a product of higher quality and the required granulometric composition. Placing a perforated scraper in an evolvent in a fluidized bed above the agitator in this way provides for the accelerated movement of large particles of the product from the center to the discharge opening.

which contributes to the uniform removal of the product from the entire surface of the fluidized bed. Turning the scraper relative to the evolvent of the nozzle installation at 60-90 allows, firstly, to remove dry granules, which after irrigation were in the layer a time approximately equal to the time of one revolution of the fluidized bed or 10-15 revolutions of the agitator, secondly, sprayed

the solution into smaller granules, which are sifted through a scraper. The provision of this process of spraying the solution onto smaller granules and removing larger dry granules requires that the rotation of the agitator coincides with the direction of unwinding of the involute. Otherwise the scraper will contribute

the movement of material from the periphery to the center of the fluidized bed.

The angle of rotation of the scraper 60-90 has been established, based on the conditions of irrigation of the granules and ensuring the maximum possible drying time after irrigation. If the angle of rotation is less than bO, then it is difficult to place the torch to cut the material so that it does not touch the scraper,

those. hard to avoid precipitation

scattered material on the scraper. Increasing the rotation angle of more than 90 leads to an unjustified reduction in the drying time of large material

pellets, which are removed with a scraper from the drying chamber.

The proposed installation allows to conduct the process of drying the solutions in the optimum mode at high

the intensity of the drying process and get high quality dried product.

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Claims (1)

INSTALLATION FOR DRYING SOLUTIONS IN A PSEUDO-LIQUIDED LAYER according to ed. St. No. 924473, distinguishing myself with the fact that, with the aim of intensifying the process and. to improve the drying quality, a perforated scraper is additionally installed between the mixer and nozzles, made according to an involute of the same circumference and the same untwisting direction as the nozzle of the nozzle installation, rotated relative to the latter by 60-90 ^ 8 direction opposite to the unwinding direction of the involute, and the end of the scraper is connected to the discharge opening. Fig 1 SU. „1153209