RU2343384C1 - Device for spray drying and granulating particulates - Google Patents

Abstract

FIELD: heating, drying.

SUBSTANCE: invention relates to technology of drying particulates and can be used in microbiological, food, chemical and other industries. Device for spray drying and granulating particulates contains case with spraying chamber placed in its upper part, equipped with atomiser and reservoir for supplying the spraying agent, spraying chamber with system of cleaning exhaust spraying agent, granulated inert material, placed gas-distributing array, brought to fluidised state by applying horizontal vibrations onto the spring-loaded case of the drying chamber through vibrator driven by guide rod, rigidly fixed to the lower part of the case, while providing elastic, compensating movement of the case. There are insertions in the upper and lower parts of the case, and the dried material together with the exhaust spraying agent is removed through an opening of the gas-distributing array in the trapping system, which consists of container, acoustic unit, cyclone collector and bag filter. The atomiser is acoustic and has case with acoustic generator in the form of nozzle and resonator placed inside, pipes for supplying the spraying agent and solution of material to be dried. The case is made in form of cup with base, and the resonator is in form of hollow rod with a wedge-shaped notch. The solution of the material to be dried enters the ring-shaped gap, formed between the outer resonator surface and the inner nozzle surface, where the channel is at a tangent to the inner surface of the cup, aligned to the case and made in form of rectangular slot. The spraying agent is supplied through pipe socket to the case and hole of the resonator, and then to the wedge-shaped notch, at an angle to the axis of the resonator, and to the ring-shaped gap between the inner surface of the cup, aligned to the case, and the outer surface of the resonator. A spiral directing device is fitted which enables the creation of vortex flow.

EFFECT: increase in efficiency of drying.

2 cl, 2 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. 232131, 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 spray drying and granulation of dispersed materials, comprising a housing with a spray chamber located in its upper part, equipped with a nozzle and a collector for supplying a spray agent, a drying chamber with a system for cleaning the spent spray agent, granular inert material placed on gas distribution grid, driven into a fluidized state by applying horizontal vibrations to the spring-loaded housing of the drying chamber by ohm of a vibrator with a drive through an earring rigidly fixed in the lower part of the body, while providing elastic compensating movements of the insert body in the upper and lower parts of the body, and the dried material together with the spent spray agent is removed through the openings of the gas distribution grill into the recovery system, consisting of a receiver, acoustic installation, cyclone and bag filter, the nozzle is made in the form of an acoustic nozzle for spraying a solution of a dried material containing a housing with a size inside the acoustic oscillation generator in the form of a nozzle and a resonator and a tube for supplying a spraying agent and a solution of the material to be dried, the body being made in the form of a glass with a bottom and the resonator in the form of a hollow rod with a wedge gap, while the solution of the material to be dried enters the annular gap made between the outer surface of the resonator and the inner surface of the nozzle, and the channel for supplying a solution of the dried material is located tangentially to the inner surface of the glass, setting coaxial to the casing, and is made in the form of a rectangular slit, while the spraying agent is fed through a fitting in the casing and the cavity of the resonator, and then enters at least one wedge slit located at an angle with respect to the axis of the resonator, the angle being in the optimal range of values: 30 ÷ 60 °, and in the annular gap between the inner surface of the glass mounted coaxially to the housing and the outer surface of the resonator there is a helical guide device that contributes to the creation of a vortex flow creator of the dried material coming through the channel.

In Fig.1 shows a diagram of an installation for spray drying and granulation of dispersed materials, Fig.2 is a diagram of an acoustic nozzle.

The initial solution is fed into the housing 1 of the drying chamber (Fig. 1), where it is sprayed by the nozzle 2. Directly with the dried material, a gaseous spraying agent is supplied, pumped by the fan 3 through the air heater 4. The spraying agent and the solution of the dried material fall into the fluidized bed 5 of granular inert material placed on the gas distribution grid 6 and brought into a fluidized state by applying horizontal vibrations to the housing 1 of the drying chamber spring-loaded by springs 13 by means of a vibrator a radiator 10 with a drive 11 through an earring 12, rigidly fixed in the lower part of the housing. In order for horizontal vibrations not to violate the integrity and strength of the installation, elastic compensating movements of the insert body 1 are provided: 8 and 9, respectively, in the upper and lower parts of the body. The spraying agent moves from top to bottom with a speed in the free section from 0.5 to 1.5 m / s. In this case, the hottest agent interacts with the most raw material, and the temperature of the spray agent may be close to the melting point (decomposition) of the dried material.

The dried material together with the spent spraying agent is removed through the openings of the gas distribution grid 6 into the capture system: receiver 7, and from there first to the acoustic unit 14, where the fine particles are agglomerated, and then to the cyclone 15 and to the bag filter 16.

The acoustic nozzle (figure 2) contains a housing 28 made in the form of a glass with a bottom 29, with an acoustic oscillation generator placed in the form of a hollow rod 21 with a wedge slot 22 and a nozzle 17. The solution of the material to be dried enters an annular gap made between the outer the surface of the resonator 21 and the inner surface of the nozzle 17 from the annular gap 18 between the inner surface of the housing 28 and the outer surface of the glass 31, mounted coaxially to the housing 28, through a channel 32 made in the side wall of the glass 31, black of the annular gap between the inner surface of the cup 31 and the outer surface of the cavity 21, the channel 32 is arranged tangentially to the inner surface of the cup 31 and is in the form of a rectangular slit.

Air is supplied through a nozzle 23 located coaxially with the nozzle body 28, through a tube 19 with an opening 24, an opening 26 made in the valve 25, coaxially with the fitting 23 and the opening 20 of the resonator 21, and then enters at least one wedge slot 22. The wedge gap 22 is located at an angle relative to the axis of the resonator 21, and the angle is in the optimal range of values: 30 ÷ 60 °. The valve 25 interacts with the seat 27, made in one piece with the resonator 21 and resting on an elastic gasket 30 located between the end surfaces of the glass 31 and the seat 27. In the annular gap between the inner surface of the glass 31 and the outer surface of the resonator 21 is placed a screw guide device 33, contributing to the creation of a vortex flow of a solution of the dried material entering the channel 32.

For the operation of the nozzle in optimal mode, the following ratios of its parameters are provided:

- the ratio of the distance h ₂ from the outer surface of the bottom 29 of the housing 28 to the lower end of the valve 25 to the distance h from the outer surface of the bottom 29 of the housing 28 to the point of intersection of the axes of the inner hole 20 of the resonator 21 with the wedge gap 22 lies in the optimal range of values: h ₂ / h = 6 ÷ 10;

- the ratio of the distance h ₂ from the outer surface of the bottom 29 of the housing 28 to the lower end of the valve 25 to the distance h ₁ from the outer surface of the bottom 29 of the housing 28 to the axis of the channel 32 for supplying the solution of the dried material lies in the optimal range of values: h ₂ / h ₁ = 1, 5 ÷ 3;

- the ratio of the diameter d of the inner hole 20 of the resonator 21 to the diameter d _{4 of the} inner surface of the housing 28 lies in the optimal range of values: d / d ₄ = 0.1 ÷ 0.3;

- the ratio of the diameter d of the inner hole 20 of the resonator 21 to the diameter d _{1 of the} outer surface of the resonator 21 lies in the optimal range of values: d / d ₁ = 0.3 ÷ 0.7;

- the ratio of the diameter d _{2 of the} nozzle 17 to the diameter d _{1 of the} outer surface of the resonator 21 lies in the optimal range of values: d ₂ / d ₁ = 1.3 ÷ 1.7;

- the ratio of the diameter d _{2 of the} nozzle 17 to the distance h ₁ from the outer surface of the bottom 29 of the housing 28 to the axis of the channel 32 for supplying a solution of the dried material lies in the optimal range of values: d ₂ / h ₁ = 3.5 ÷ 4.5;

- the ratio of the diameter d of the inner hole 20 of the resonator 21 to the distance h from the outer surface of the bottom 29 of the housing 28 to the point of intersection of the axes of the inner hole 20 of the resonator 21 with the wedge gap 22 lies in the optimal range of values: d / h = 0.3 ÷ 0.7.

Installation for spray drying and granulation of dispersed materials works as follows.

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 spray agent. The installation allows to obtain fine powders due to the additional abrasion of the material in a vibro-boiling layer of inert granules. The solution of the dried material is fed into the housing 1 of the drying chamber through the nozzle 2, and the sawing agent moves in parallel current with the solution of the dried material.

The acoustic nozzle operates as follows. The spraying agent, for example air, is supplied through the opening 24 of the tube 19, then the opening 26 made in the valve 25, and the opening 20 of the resonator 21, after which it enters at least one wedge slot 22. A solution of the dried material through the channel 32 made in the side wall of the cup 31, it enters the annular gap between the inner surface of the cup 31 and the outer surface of the resonator 21. As a result of the passage of the resonator 21 by a spray agent, for example air, pressure pulsations arise in the latter, creating acoustic fluctuations, the frequency of which depends on the parameters of the resonator. Acoustic vibrations of the spraying agent contribute to finer atomization of the solution supplied to the annular gap, while impacting, it creates sound vibrations affecting the stream of the solution of the dried material. The specified nozzle provides good spray quality at low spraying agent costs. The experiments showed that at an air pressure of 100 kPa, the average droplet diameter is 90 μm, with an increase in air pressure by about 4 times (up to 400 kPa), the average droplet diameter decreases slightly and amounts to 87 μm.

Pneumatic acoustic 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 performance of pneumatic nozzles 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. Pneumatic acoustic nozzles as well as hydraulic ones can be installed one at a time or combined into blocks of up to 50 pieces.

Claims (2)

1. Installation for spray drying and granulation of dispersed materials, comprising a drying chamber housing with a nozzle and a collector for supplying a spraying agent in its upper part, a system for collecting spent spraying agent, a granular inert material placed on a gas distribution grid, brought into a fluidized state by applying horizontal oscillations on the spring-loaded housing of the drying chamber by means of a vibrator driven by an earring rigidly fixed at the bottom hour the case, provided with elastic, compensating for the movement of the insert body in the upper and lower parts of the body, and the dried material together with the spent spray agent is removed through the openings of the gas distribution grid into the capture system, consisting of a receiver, acoustic installation, cyclone and bag filter, characterized in that the nozzle is made in the form of an acoustic nozzle for spraying a solution of a dried material containing a housing with an acoustic oscillator located inside in the form of a nozzle and a resonator, a tube for supplying a spraying agent and a solution of the material to be dried, the body being made in the form of a glass with a bottom, and the resonator in the form of a hollow rod with a wedge gap, while the solution of the material to be dried enters an annular gap made between the outer the surface of the resonator and the inner surface of the nozzle, and the channel for supplying a solution of the dried material is located tangentially to the inner surface of the glass, mounted coaxially to the body, and is made in the form of a rectangular the gap, while the spraying agent is fed through the nozzle in the housing and the hole of the resonator, and then enters at least one wedge slot located at an angle with respect to the axis of the resonator, the angle being in the optimal range of values: 30 ° ÷ 60 °, and in the annular gap between the inner surface of the glass, mounted coaxially with the housing and the outer surface of the resonator, there is a helical guide device that contributes to the creation of a vortex flow of a solution of the dried material coming through channel. 2. Installation for spray drying and granulation of dispersed materials according to claim 1, characterized in that the ratio of the distance h ₂ from the outer surface of the bottom of the housing to the lower end of the valve to the distance h from the outer surface of the bottom of the body to the point of intersection of the axes of the inner hole of the resonator with the wedge gap lies in the optimal range of values: h ₂ / h = 6 ÷ 0; the ratio of the distance h ₂ from the outer surface of the bottom of the body to the lower end of the valve to the distance h ₁ from the outer surface of the bottom of the body to the axis of the channel for supplying the solution of the dried material lies in the optimal range of values: h ₂ / h ₁ = 1,5 ÷ 3; the ratio of the diameter d of the inner hole of the resonator to the diameter d _{4 of the} inner surface of the housing lies in the optimal range of values: d / d ₄ = 0.1 ÷ 0.3; the ratio of the diameter d of the inner hole of the resonator to the diameter d _{1 of the} outer surface of the resonator lies in the optimal range of values: d / d ₁ = 0.3 ÷ 0.7; the ratio of the diameter d _{2 of the} nozzle to the diameter d _{1 of the} outer surface of the resonator lies in the optimal range of values: d ₂ / d ₁ = 1.3 ÷ 1.7; the ratio of the diameter d _{2 of the} nozzle to the distance h ₁ from the outer surface of the bottom of the housing to the axis of the channel for supplying the solution of the dried material lies in the optimal range of values: d ₂ / h ₁ = 3.5 ÷ 4.5; the ratio of the diameter d of the inner hole of the resonator to the distance h from the outer surface of the bottom of the housing to the point of intersection of the axes of the inner hole of the resonator with the wedge gap lies in the optimal range of values: d / h = 0.3-0.7.

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