RU2335715C1 - Plant for solution, suspension and spreads drying - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: plant for solution, suspension and spread drying includes drying chamber with oscillating granulator locating in the central part, and spraying chamber is located in the upper part of its housing. Spraying chamber is provided with injectors and coolant supply header. Plant is also equipped with solution supply system and spent coolant cleaning system. Gas-distributing system is equipped with two gas-distributing units: upper and lower. Upper gas-distributing unit supplies coolant to spray cone and is intended for even coolant distribution along sprayed material cone. Lower gas-distributing unit supplies coolant to bottom part of housing where gas-distributing lattice with nozzles for secondary coolant supply and discharge hopper for granules is installed. Oscillating granulator is represented as swirling flow with meshed bottom. Injector contains housing with chamber where screw with the external threaded groove is located. Besides, bottom of housing is provided with throttling opening. Choke with cylindrical opening is in the top of housing. Threaded opening is available inside screw and agitating chamber is situated under the screw. Agitating chamber consists of cylindrical and tapered parts. Screw is rigidly linked with T-shaped throttle plate, where at least three throttling openings are made in its end cylindrical part. Axial throttling opening is available in axial cylindrical part rigidly connected to end cylindrical part. In addition, hydraulic resistance of throttling openings is selected in dependence on properties of sprayed liquid and required rate of dispersion.

EFFECT: improvement of drying efficiency.

4 cl, 3 dwg

Description

The invention relates to techniques for drying dispersed materials and can be used in microbiological, food, chemical and other industries.

The closest technical solution to the claimed object is a dryer by.with. USSR No. 182581, F26B 3/12, 1964, containing a drying chamber, a gas distribution system of a drying agent, a solution supply system and an exhaust air purification system (prototype).

The disadvantage of the prototype is the relatively low productivity of drying the final product.

The technical result is an increase in drying performance.

This is achieved by the fact that in the installation for drying solutions, suspensions and pasty materials, containing a drying chamber with a vibrating granulator located in the central part, in the housing of which a spray chamber equipped with a nozzle and a collector for supplying a coolant, a solution supply system and the waste heat carrier cleaning system, and the gas distribution system is equipped with two gas distributors: the upper and lower, while the upper gas distributor brings the coolant to the spray nozzle is designed to evenly distribute the coolant along the spray of the sprayed material, and the lower gas distributor allows the coolant to be introduced into the lower part of the housing, where the gas distribution grill with nozzles for supplying the secondary coolant and estrus for the exit of the granules is installed, and the vibration granulator is made in the form of a vibrating tray with mesh bottom, according to the invention, the nozzle comprises a housing with a chamber, in which is located a screw with a helical external groove, and in the bottom of the core a throttle aperture is made in the pus, and a fitting with a cylindrical hole is placed in the upper part, and a screw-threaded hole is made inside the screw, and a mixing chamber consisting of cylindrical and conical parts is located under the screw, and the screw is rigidly connected to the T-shaped throttle washer, in the end cylindrical part of which has at least three throttle openings, and in the axially cylindrical part rigidly connected to it, an axial throttle bore, and the hydraulic resistance of the throttle holes selected depending on the properties of the spray solution and the desired degree of atomization.

In Fig.1 shows a diagram of an installation for drying solutions, suspensions and pasty materials, Fig.2 is a variant of a vibratory granulator, Fig.3 is a centrifugal nozzle for spraying solutions.

Installation for drying solutions, suspensions and pasty materials (figure 1) contains a housing 1 with a spray chamber 2 located in its upper part, a nozzle 3 and a collector 4 for supplying coolant 16 from above. The coolant is returned through the channel 15 between the housing 1 and the spray chamber 2 located in its upper part. The dried material enters the vibration granulator, made in the form of a vibrating tray 5 with a mesh bottom 6 and a ball nozzle 7 spring loaded from above and below by springs 13, driven by a vibrating vibrator 11. The housing 1 at the location of the vibrator is made detachable with spring-loaded springs 12 parts. Under the weight of the ball nozzle, the material is forced through the mesh bottom, and under the influence of the vibration of the tray and the gravity of the particles themselves, the latter are torn off, of the same size. Then the particles fall into the lower part of the housing, where a gas distribution grid 8 with a pipe 9 for supplying a secondary coolant is installed. Here, the material is dried in the fluidized bed mode and in the form of granules of the same size is released through estrus 10.

Figure 2 presents an embodiment of a vibratory granulator in the form of a vibrating tray 5 with a mesh bottom 6 with a perforation coefficient equal to 0.3 ... 0.5, and elastically fixed to the bottom 6 by means of springs 14 of a perforated plate 17 with a perforation coefficient equal to 0.5 ... 0.7. The vibrodrive 11 has a control unit (not shown in the drawing), which changes the direction, amplitude and frequency of vibration in the required optimal range of granulator operation parameters: vibration level in the range - 100 ... 120 dB, oscillation process frequency in the range - 50. ..100 Hz, and the perforated plate 17 performs the functions of the inertial mass of a dynamic vibration damper tuned to the desired frequency range. The spring-loaded perforated plate 17 oscillates in a vertical plane and transmits vibrational energy for mixing and forcing through the mesh bottom 6. Exhaust dusty gases are subjected to preliminary acoustic treatment in acoustic installation 18, the optimal parameters of which for sound processing of medium-fine dust are: sound pressure level 140 dB and more, the frequency of the oscillatory motion of 900 Hz, the concentration of dust in the air stream is at least 2 g / m, scoring time 1.5 ... 2 s, after which the gas stream is sent to the cyclone 19 with a hopper, where the main part of the dry material carried away by the gases is released, and the final cleaning of the gases takes place in the bag filter 20.

The centrifugal nozzle (Fig. 3) consists of a housing 21 with a cover 23, inside of which there is a screw 22. The outer surface of the screw 22 is a helical groove with right (or left) thread. Inside the screw 22, a hole 31 is made with a left (or right) screw thread. At the bottom of the housing 21, a throttle hole 29 is made, the axis of which coincides with the axis of the hole 31 in the screw 22. Between the lower end of the screw 22 and the slice of the throttle hole 29 there is a mixing chamber consisting of a cylindrical 28 and a conical 30 parts.

The screw 22 is rigidly connected to the T-shaped throttle washer 25, in the end cylindrical part 24 of which at least three throttle openings 26 are made, and in the rigidly connected axial cylindrical part there is an axial throttle hole 33. The hydraulic resistance of the throttle openings 26 and 33 is selected depending on the properties of the sprayed liquid and the desired degree of spray.

The supply of the solution (liquid) is carried out through the hole in the fitting 27, mounted in the upper part of the housing 21 through the end cylindrical part 24 of the T-shaped throttle washer 25.

The gas distribution system is equipped with two gas distributors: an upper and a lower one, while the upper gas distributor brings the drying agent to the root of the spray jet and is designed to evenly distribute the coolant along the spray of the sprayed material, and the lower gas distributor allows the coolant to be introduced into the lower part of the housing where the gas distribution grill with nozzles for supply of secondary coolant and estrus for the exit of the granules.

Installation for drying solutions, suspensions and pasty materials works as follows.

A high evaporation rate of moisture is achieved in the dryer due to fine atomization of the dried material in the drying chamber through which the drying agent (heated air or flue gases) moves. When spray drying, the specific evaporation surface becomes so large that the drying process is completed extremely quickly (in about 15 ... 30 s).

In the spray dryer, the material is fed into the chamber 2 through the nozzle 3. The drying agent moves in parallel current with the material through the collector 4. The dried material enters the vibration granulator, which is made in the form of a vibrating tray 5 with a mesh bottom 6 and a ball nozzle 7, spring-loaded from above and below by springs 13. driven by vibrator 11. Housing 1 at the location of the vibrator is made detachable with spring-loaded springs 12 parts. Under the weight of the ball nozzle, the material is forced through the mesh bottom, and under the influence of the vibration of the tray and the gravity of the particles themselves, the latter are torn off, of the same size. Then the particles fall into the lower part of the housing, where a gas distribution grid 8 with a pipe 9 for supplying a secondary coolant is installed. Here, the material is dried in the fluidized bed mode and in the form of granules of the same size is released through estrus 10.

Small solid particles of dried material (up to several microns in size) are discharged through a collector located between the spray chamber 2 and the housing 1, and enter the output collector, and from there, first into the acoustic unit, where the small particles are agglomerated, and then into the cyclone and into a bag filter (not shown in the drawing). Spent drying agent after cleaning from dust in the cyclone and bag filter is released into the atmosphere.

The nozzle 3 operates as follows.

The fluid is supplied through an opening in the nozzle 27 and through a T-shaped throttle washer 26 enters simultaneously in two directions: firstly, into the screw outer cavity 32 of the screw 22 through the throttle holes 26, and secondly, into the screw hole 31 through the throttle hole 33. A rotating fluid flow from the screw outer cavity 32 of the screw 22 enters the mixing chamber, consisting of a cylindrical 28 and a conical 30 parts. On the other hand, liquid enters the mixing chamber from a screw-threaded hole 31, rotating in the direction opposite to the external flow going through the screw 22, or performing a passing (identical) rotation. In the interaction of rotating flows in the mixing chamber, additional droplets of liquid are crushed due to their collision in associated or opposite rotating liquid flows (external and internal). The total fine rotating flow exits through the throttle hole 29, and the direction of its rotation is determined by the hydraulic resistance of the external 32 or internal screw cavities 31 of the screw 22, respectively.

The nozzle screw 22 can be made of solid materials: tungsten carbide, ruby, sapphire. With an average diameter of the throttle hole 29, which is in the range of 2.5 ... 3.5 mm, and a fluid pressure of 6 ... 9 MPa, atomization of 400 to 1000 kg / h of fluid is ensured. The nozzle is easy to manufacture and maintain.

The voltage of the evaporated moisture for this dryer is 2.5 ... 3 times greater than for dryers with conventional gas distribution. Spraying can be carried out with pneumatic nozzles or with the help of centrifugal sprayers (not shown in the drawing), the rotation speed of which is 4000 ... 20,000 rpm.

Pneumatic nozzles operate on the principle of spraying a liquid with a high-speed jet of gas or steam supplied under a pressure of 0.1 ... 1.0 MPa. The nozzle capacity reaches 12 t / h; they are highly versatile in regulating the shape of the torch, productivity, dispersion of the spray and the ability to spray high viscosity pastes and suspensions. Spray dryers also work according to the principles of counterflow and mixed current. However, direct flow is especially common, as it allows drying at high temperatures without overheating of the material, and the rate of deposition of particles in this case is the sum of their speed and the speed of the drying agent. This type of spray dryer is used to dry solutions, suspensions and pasty materials.

Claims (4)

1. Installation for drying solutions, suspensions and pasty materials, containing a drying chamber with a vibration granulator located in the central part, in the housing of which a spray chamber is located in its upper part, equipped with a nozzle and a collector for supplying a heat carrier, a solution supply system and a waste heat carrier cleaning system and the gas distribution system is equipped with two gas distributors: the upper and lower, while the upper gas distributor brings the coolant to the root of the spray torch and It is designed for uniform distribution of the coolant over the sprayed material torch, and the lower gas distributor allows the coolant to be introduced into the lower part of the housing, where the gas distribution grill with nozzles for supplying the secondary coolant and estrus for the exit of granules is installed, and the vibration granulator is made in the form of a vibrating tray with a mesh bottom the fact that the nozzle comprises a housing with a chamber in which a screw with a screw external groove is located, wherein a throttle is made in the bottom of the housing th hole, and in the upper part there is a fitting with a cylindrical hole, and a screw hole is made inside the screw, and a mixing chamber consisting of cylindrical and conical parts is located under the screw, and the screw is rigidly connected to the T-shaped throttle washer in the end cylindrical parts of which are made of at least three throttle holes, and in the axially cylindrical part that is rigidly connected to it, an axial throttle hole, and the hydraulic resistance of the throttle holes is selected Depending on the properties of the spray solution and the desired degree of atomization. 2. Installation according to claim 1, characterized in that the perforation coefficient of the mesh bottom is 0.3 ... 0.5, while on the bottom by means of springs a perforated plate with a perforation coefficient of 0.5 ... 0 is resiliently fixed 7, and the vibrodrive has a control unit, with the help of which the direction, amplitude and frequency of vibration are changed in the required optimal range of granulator operation parameters: vibration level in the range of 100 ... 120 dB, oscillation process frequency in the range of 50 ... 100 Hz. 3. Installation according to claim 1, characterized in that the direction of the screw thread of the hole made inside the nozzle screw is the same or opposite to the direction of the screw outer groove of the screw. 4. Installation according to claim 1, characterized in that the nozzle screw is made of solid materials: tungsten carbide, ruby, sapphire.

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