SU901780A1 - Dryer for polydispersed materials - Google Patents

Description

The invention relates to convective drying of loose materials, especially those whose granulometric composition is extremely heterogeneous, and can be used in the chemical construction, energy, food and other industries. Dryers for bulk materials in suspension are known, comprising a partitioned drying chamber with a perforated bottom. A disadvantage of the known dryers is the need to maintain a certain speed of the drying agent in the working chamber to provide a suspended state of the layer, while the magnitude of the speed depends on many factors: size, density and humidity of the particles of material, temperature and humidity of the drying agent, dryer geometry. environmental protection, material and heat balance, the economy of the process, the value of the allowable ablation of material, etc. All this makes it difficult to control the speed of the drying agent. If the speed is not high enough, large particles remain on the gas distribution screen, with an increase in the speed the ablation of small particles with a drying agent sharply increases, the number of dry particles that are prematurely removed from the drying zone increases; this reduces the quality of drying. Che (the more heterogeneous the particle size distribution of the material being dried is, the more difficult it is to choose the optimal speed of the drying agent. In order to avoid increased entrainment of material from the drying chamber above the drying zone, a separation space is provided that is larger in volume than the actual drying zone. Therefore, the porosity of the layer of material referred to the entire volume of the drying chamber approaches one, which significantly reduces eg 390

The volume of the drying chamber is evaporated with moisture and leads to an increase in the size of the installation. In addition, to reduce material losses with exhaust drying agent and environmental protection, separately placed gas cleaning devices are included in the composition of the drying equipment in a suspended state; , usually larger than the dryer itself, and contain fairly complex unloading and transport units.

Also known are dryers containing a chamber with a gas distribution grid and a agitator and a separator of sticky fractions placed above it.

In these dryers there is no steady movement of the material, that. leads to a decrease in the quality of drying, especially for difficult-drying materials.

Closest to the present invention, there is a dryer for polydisperse materials, comprising a drying chamber with a perforated bottom, over which a screw is installed, which moves the material from the loading unit to the discharge point. The drying agent is blown through the bottom of the chamber through a layer of material being dried and is discharged from above. The chamber is divided by vertical partitions and adjacent compartments, and has a bottom; The rectangular form of the drawbacks of the described dryer refers to the impossibility of increasing the speed of the drying agent to values greater than the soaring speed of the largest particles, since the ablation of the material with the drying agent and the penetration of the undried particles of the material to the place of discharge, which reduces the quality of drying, sharply increase. In such a dryer, it is difficult to achieve a uniform distribution of the material along the length of the drying chamber.

The purpose of the invention is to intensify the process and improve its quality.

This goal is achieved by the fact that a semi-cylindrical filter equipped with a rotating brush cleaner and a wet dust collector located above the filter are placed in the chamber above the partitions, and the auger is extended beyond the extreme compartments by an amount greater than its pitch, and the cleaner and the screw are connected by mechanical transmission ..

04

FIG. 1 shows schematically the proposed dryer; in fig. 2 is a section A-A in FIG.

The dryer contains a drying chamber.

1 rectangular section with a perforated bottom 2, above which a screw 3 is placed, rotating from the drive Ts. The chamber 1 has a loading 5 and a loading 6 hoppers. In the chamber 1, a semi-cylindrical filter 7 is installed, equipped with a rotating brush cleaner 8, and located above ({7 the wet bubbling dust collector 9). To rotate the cleaner

8 a chain drive 10 is provided from the screw 3; The drying chamber 1 is divided by vertical transverse partitions

11to the compartments. Between the loading hopper 5, the drying chamber 1 and the discharge hopper 6 there are valve sections 12, to which the screw 3 is extended outside the chamber 1 and which are larger than the screw auger 3 pitch. For supply and retraction

a drying agent are pipelines 13 and C.

The dryer works as follows.

The material from the hopper 5 is fed through the gate portion

12 with screw 3 into the drying chamber 1, where it is dried, during which time the material moves along the chamber partially with screw 3 partially

flows through the bulkheads 11 and further through the valve section 12 is supplied to the discharge bin 6. The drying agent is supplied from below through conduit 13, therefore it passes through the perforated bottom 2, drying chamber 1, filter 7 dust collector 9 and is discharged upward through pipeline 1k.

Claims (3)

The speed of the drying agent in chamber 1 is established, of course, higher than the soaring speed of the largest and heaviest particles, and thus, the suspension of all particles is guaranteed, the need for controlling the feed rate of the drying agent is eliminated, the entire volume of the drying chamber is filled with a layer of material with porosity 0, 5-0.6, evenly distributed along the length of the drying chamber due to the presence of partitions 11. The formation of stagnant zones or free channels in the layer is prevented due to the operation of the screw. 59 Everything. this contributes to the intensification of the drying process and significantly increases the intensity of the volume of the drying chamber with respect to evaporating moisture, which leads to a decrease in the dimensions of the dryer. The material is dried evenly, since there is almost no leakage of undried material through the drying chamber. and, at the same time, the possibility of formation of stagnant zones and drying of the material is almost eliminated. The built-in filter and the wet dust collector prevent material loss, clean the drying agent and contribute to process intensification and environmental protection. Such devices increase the compactness of the entire installation as a whole with relative ease of manufacture. Claim 1. Dryer for polydisperse materials, containing rectangular chamber with perforated bottom, divided by vertical subdivisions into adjacent compartments, and placed above the bottom auger, characterized in that, in order to intensify the process and improve its quality, in the chamber above the partitions additionally placed is a semi-cylindrical filter, equipped with a rotating brush cleaner, and a wet dust collector located above the filter, and the auger is extended beyond the limits of the extreme compartments to well, big of his step. 2. Dryer POP.1, characterized in that the cleaner and the screw are interconnected by means of a mechanical transmission. Sources of information taken into consideration in the examination 1. PG Romanov, N.B. Rashkovska Drying in a boiling bed. M.-L., Chemistry, Tabby, p. 128-11 8. 2. USSR author's certificate ff i 28l79, cl. F 26 B 17/2, 1972. 3.Romankov P.G., Rashkovska N.B. Drying in suspension, L., Khimi, 1968, p. 91.