RU192072U1 - DRYING UNIT OF BOILING LAYER FOR DRYING LITHIUM HYDROXIDE - Google Patents

Abstract

The invention relates to a fluidized-bed dryer assembly comprising a drying chamber in a housing, a gas distribution grill, wet material supply pipes, coolant supply and removal and dry product discharge. The unit is equipped with an agitator and distribution mechanism mounted above the gas distribution grid. The irrigation and distribution mechanism is made in the form of a shaft with blades fixed on it with the possibility of rotation, consisting of rods of different lengths and blades. The coolant supply pipes equipped with throttle valves, with the ability to control the coolant supply, are fixed under the gas distribution grill. The lower and upper parts of the body consist of a main volume, the cross-section of which is an isosceles trapezoid, interconnected by a large base of the lower and upper parts. The elements of the dryer, located from the nozzle for supplying wet material to the nozzle for unloading the dry product, are made of non-corrosive material, such as stainless steel. 2 s.p. f-ly, 5 ill.

Description

The technical solution relates to the field of devices for drying wet materials in a fluidized bed and can find application in chemical, food, pharmaceutical and other industries.

Known dryer with a fluidized (boiling) layer of material (Dytnersky YI Processes and apparatuses of chemical technology: A textbook for high schools. Ed. 2nd. In 2 books. Part 2. Mass transfer processes and apparatuses. M: Chemistry, http: //1995.-p.264). The drying agent is fed under the grate, rises up into the drying chamber, into which wet bulk material is fed by a screw feeder. The wet material is fluidized to fill a certain volume of the drying chamber. The incoming wet bulk material extrudes the dried bulk material to the discharge screw. The disadvantage of this design is that it mixes the dried and wet materials (freshly received).

A known installation for drying crushed products in a fluidized bed (USSR Author's Certificate 573693, IPC F26B 17/10, 1977), containing a multi-section chamber with a gas distribution grill, transverse, vertically installed vertical partitions in the loading section and nozzle nozzles.

In this installation it is impossible to obtain a product with the same humidity due to uneven drying of the particles of the starting material, the presence of stagnant zones in the product layer, especially in the loading zone. An increased flow rate of the coolant through the gas distribution grill and nozzles is required, which will cause significant entrainment of the finely dispersed product from the apparatus.

A known fluidized bed dryer (USSR Author's Certificate 879217, IPC F26B 17/10, 1981), comprising a housing with a horizontal gas distribution cylindrical chamber connected to the housing through a slit, and a device for pulsating coolant supply, located inside the chamber and made in the form of a movable segmented damper with a drive that overlaps when turning the gap between the gas distribution chamber and the housing.

The disadvantages of this dryer are significant losses of the product with waste heat carrier during drying of polydisperse materials, clogging of the filter holes with finely dispersed material, low productivity of the dryer and poor fluidization of the product due to the small filter area.

The closest technical solution - a prototype to the claimed object is a dryer, a suspended layer, consisting of a housing, a gas distribution grill with holes, nozzles for loading material, unloading material, supplying coolant for a drying agent and removal of spent coolant. The lattice of the dryer is made curvilinear in the area adjacent to the discharge opening so that the center of curvature is located below the lattice and this part of the lattice is inclined towards the discharge opening. Due to this, in the last drying section, the dried material falls under the action of the drying agent jets deflecting it towards the discharge opening (RF Patent 109541, IPC F26B 17/10, publ. 20.10.2011).

The disadvantages of the prototype include uneven drying of the material, the lack of tedding of the material and, as a result, low drying efficiency, increased energy consumption, reduced productivity and reduced drying quality. In the dryer it is not possible to change the direction and feed rate of the drying agent into the drying chamber without changing the grate.

The problem to which the claimed utility model is directed is to obtain a finished product with the least amount of metallomagnetic impurities at the lowest energy consumption.

The technical result achieved in this case is to ensure a clean finished product without mechanical impurities and to reduce operating costs, i.e. effective drying, by intensive evaporation of moisture with minimal air supply, which reduces the energy consumption of the coolant and almost completely eliminates dust extraction.

Since it is known that a feature of drying lithium hydroxide is the need to maintain a balance between air supply and temperature, and with an uncontrolled increase in the volume of supplied air, undesired carbonization of lithium hydroxide occurs.

The specified technical result is achieved by the fact that the fluidized bed drying unit containing a drying chamber in the housing, a gas distribution grid, wet material supply pipes, coolant supply and removal pipes and a dry product unloading, according to the claimed solution, is equipped with an agitating and distribution mechanism mounted above the gas distribution grid, and under the gas distribution grill there are fixed coolant supply pipes equipped with throttle valves, with the possibility of regulating the flow of t carrier, the lower and upper parts of the body consisting of the main volume, the cross section of which is isosceles trapezoid, interconnected by a large base of the lower and upper parts, and the dryer elements located from the supply pipe of the wet material to the discharge pipe of the dry product are made of non-corroding material.

The device is complemented by private distinctive features that contribute to the achievement of the claimed technical result.

The irrigation and distribution mechanism can be made in the form of a shaft with blades mounted on it with the possibility of rotation, consisting of rods of different lengths and blades.

Gas distribution grill, drying unit housing, gas supply duct, coolant supply pipes, throttles, agitator and distribution mechanism are made of steel.

The essence of the technical solution is illustrated by drawings.

FIG. 1 shows a general view of a fluidized bed dryer;

FIG. 2 - view of the unit on the left;

FIG. 3 - agitating and distribution mechanism of the rod type;

FIG. 4 is a left view of the agitator;

FIG. 5 - gas distribution grill (fragment).

The fluidized-bed drying unit comprises a housing 1 in the form of two isosceles trapezoidal plates, interconnected by a large base of the lower and upper parts with a gas distribution grid 2 located in the lower part representing a perforated surface. An air collector 3 is attached to the housing for distribution of the coolant. The drying chamber is located in the drying unit housing and occupies a volume above the gas distribution grill. To supply the coolant, a gas supply duct is made 4. The air collector 3 can be made in the form of dividing pipes with throttle valves 5, each of which consists of a housing, a valve with an axis, and a drive mechanism (not marked in Fig.). The collector is divided into several zones by dividing pipes, each of which is equipped with an adjustable throttle for adjusting the parameters of the incoming air of each zone in order to ensure an effective technological process of drying the raw material. For feeding wet material from a hopper located in the front of the housing, a rod-type agitating and distributing mechanism is installed above the gas distribution grid 2. The agitating and distributing mechanism is made in the form of a shaft 6.1 with blades rotating on it, consisting of rods 6.2 of different lengths and 6.3 blades . Made the number of agitator blades equal to at least eight and their location at an angle of 45 °. A pipe 7 is provided for unloading the dry finished product located at the rear of the housing 1. To extract spills, as well as when the drying unit stops working, an auger 8 for unloading dry material from the drying chamber through the pipe 9 is made. To remove the spent heat carrier, a pipe is located in the housing cover 1 10. The wet material hopper is equipped with a material supply pipe. To supply the heated coolant, a fan 12, a filter 13, an air heater 14 are installed.

A fluidized bed dryer for drying lithium hydroxide works as follows.

The fan 12 through the filter 13 pumps air into the air heater 14, from where the heated fluidizing fluid passing the air manifold installed above the gas supply duct is fed under the gas distribution grid 2. The heated heat carrier from the air heaters 14 is pumped into the gas supply air duct 4, from where it enters with throttling dampers 5 to the gas distribution grid 2. The flow of coolant into the drying chamber is manually controlled by closing or opening the throttles 5.

Wet material from the hopper is fed to the gas distribution grid 2 through a rod-type agitating and distributing mechanism 6 with a frequency-controlled drive. The agitator ensures even distribution of the wet material at the beginning of the gas distribution grid. The material is loaded into the housing through the nozzle of loading the wet material 11. Unloading of the dry finished product is carried out through the nozzle 7 located in the rear of the housing. To extract spills, as well as when the drying unit is stopped using the discharge screw 8, the material is completely discharged from the drying chamber through the pipe 9. The waste heat carrier is discharged through pipes 10 located in the housing lid to the dust cleaning system.

An upward flow of hot air heats and dries the feed. The source material on the gas distribution grid is in a suspended state ("fluidized bed"), gradually moving to the place of unloading of the dry product. The speed of the coolant decreases along the length of the grate by regulating the throttles, which leads to a decrease in mixing of the dried and wet material and to obtain a dried product at the discharge end and allow to maintain a uniform and stable "boiling".

The irrigation and distribution mechanism due to the design and the optimal rotation mode of the blades ensures uniform initial distribution of the wet material along the gas distribution grill in the front of the housing. When wet material gets on the agitating and distributing mechanism, it is picked up by the blades, which ensures the exclusion of agglomeration and sticking to the gas distribution grid.

To exclude mechanical rubbing and introducing metal-magnetic impurities into the finished product, all components and parts (gas distribution grill, drying unit housing, gas supply duct, coolant supply pipes, throttles, agitating and distributing mechanism) in contact with the starting and finished products are made of non-corroding material strength characteristics not inferior to metal (stainless steel).

Due to the proposed execution of the shape of the case, the cross-sectional area increases in the upper part of the case, which reduces the speed of the spent coolant and ensures minimal dust extraction.

Claims (3)

1. The fluidized-bed dryer unit comprising a drying chamber in the housing, a gas distribution grill, wet material supply pipes, a coolant supply and removal unit, and a dry product discharge, characterized in that the unit is equipped with an agitator and distribution mechanism installed in the drying chamber above the gas distribution grid, and under the gas distribution grill there are fixed coolant supply pipes equipped with throttle valves, with the possibility of regulating the coolant supply, while the lower and The upper parts of the body consist of the main volume, the cross-section of which is isosceles trapezoid, interconnected by a large base of the lower and upper parts, and the dryer elements located from the nozzles of the supply of wet material to the discharge of the dry product are made of non-corrosive material. 2. The drying unit according to claim 1, characterized in that the agitating and distributing mechanism is made in the form of a shaft with blades mounted on it with the possibility of rotation, consisting of rods of different lengths and blades. 3. The drying unit according to claim 1, characterized in that the gas distribution grill, the drying unit housing, the gas supply duct, coolant supply pipes, throttles, agitator and distribution mechanism are made of stainless steel.

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