RU2313744C1 - Drying apparatus with inert head for suspended layer - Google Patents

Abstract

FIELD: equipment for drying of dispersion materials, used in microbiological, food-processing, chemical and other branches of industry.

SUBSTANCE: drying apparatus has steam heating coil and electric heater, fluidized bed unit with distribution grid, pressure and exhaust fans, cyclone group with discharge device, tank for basic solution delivered into apparatus through spraying nozzles, dosing pump, inlet air filter, and hot rinsing water measuring device. Working chamber for fluidized bed unit is positioned in its lower part and is filled with inert particles of fluorine plastic. There is acoustic unit at inlet end of cyclone group. Fluorine plastic particles are 4.5x4 mm sized. Working chamber has height of 500 mm and diameter of 400 mm. Flexible wire strings are stretched above plane of distribution grid of working chamber of apparatus. Acoustic treatment parameters of acoustic unit for average-sized dispersion dust concentration in air flow of at least 2 g/m³ are: acoustic pressure level ranging between 140 dB and 150 dB, vibration process frequency ranging between 800 Hz and 1,000 Hz, sonification duration ranging between 1.5 s and 2 s.

EFFECT: increased efficiency in drying of various materials.

2 cl, 1 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 described in patent RU 2083490, СВВ 31/06, 07/10/1997 and containing a heater, a fluidized bed apparatus with a distribution grid, pressure and exhaust fans, a cyclone group with a discharge device, a tank for the initial solution entering the apparatus through spray nozzles, a metering pump, while the working chamber of the fluidized bed apparatus is located in its lower part and is filled with inert particles of fluoroplastic.

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 the dryer of the suspended layer with an inert nozzle contains steam and electric heaters, a fluidized bed apparatus with a distribution grid, pressure and exhaust fans, a cyclone group with a discharge device, a tank for the initial solution entering the apparatus through spray nozzles, a metering pump, air inlet filter and hot water meter for flushing. The working chamber of the fluidized bed apparatus is located in its lower part and is filled with inert particles of fluoroplastic. An acoustic installation is installed at the inlet of the cyclone group, fluoroplastic particles are 4.5 × 4 mm in size with a working chamber height of 500 mm and a diameter of 400 mm, and elastic wire strings are stretched over the distribution grid of the working chamber of the apparatus. The parameters for sound processing in an acoustic installation of medium-sized dust with its concentration in the air stream of at least 2 g / m ³ are: sound pressure level in the range of 140 ... 150 dB, oscillation process frequency in the range of 800 ... 1000 Hz, dubbing time in the range of 1.5 ... 2 s.

The drawing shows a diagram of a dryer of a suspended layer with an inert nozzle.

The suspended layer dryer with an inert nozzle contains a fluidized bed apparatus 1 with a distribution grid, steam heaters 2 and electric 3, pressure head 12 and exhaust fans 4, an air intake filter 5, a cyclone group 6 with a discharge device 11, at the input of which an acoustic unit 13 is installed, a tank for the initial solution 7 entering the apparatus through spray nozzles, a hot water meter for flushing 8 and a metering pump 9. The working chamber of the apparatus 1 of the fluidized bed is located in its lower part and is filled with inert and fluoroplastic particles 10 of a size 4,5 × 4 mm and a height of 500 mm the working chamber.

To intensify the drying process of phytochemicals by accelerating the abrasion of the film of the dried product from the surface of inert particles of the film over the plane of the distribution grid of the working chamber of apparatus 1, elastic wire strings are stretched (not shown). When the layer is liquefied, inert particles hit the stretched strings, which contributes to the abrasion of the film of the dried product from their surface.

The optimal parameters for sound processing in an acoustic installation of 13 finely dispersed dust with its concentration in the air stream of at least 2 g / m are: sound pressure level in the range 140 ... 150 dB, oscillation process frequency in the range 800 ... 1000 Hz, time scoring in the range of 1.5 ... 2 s.

A suspended layer dryer with an inert packing works as follows.

The drying process begins after the heaters 2, 3 and fans 4 and 12 are turned on. With a stream of air, the inert particle layer 10 liquefies. After heating the particles to 100 ° C, the solution begins to flow from the tank 7 onto them, while the moisture evaporates and the dry product covers the inert particles 10 with a thin layer. As a result of the collision of the particles, the film is abraded, and the product is carried out by air from the fluidized bed of the apparatus 1 to the acoustic unit 13, then to the cyclone group 6, from where it is poured into the container of the unloading device 11, and the moist air is discharged into the atmosphere.

The dried liquid disperses and irrigates the suspended layer of inert particles 10, which are heated by a blown hot gas and serve as a heat transmitter. Moisture evaporates from the surface of the particles, and they are covered with a thin film of material, and due to the significant rate of evaporation of moisture, the limiting process is the abrasion of the dried product from the surface of the particles.

The drying agent, together with small particles of the product (heated air or flue gases), enters the acoustic column, the sound vibration parameters of which are adjusted from the control unit. In the acoustic column, dust particles are separated from the air, since under the influence of the sound field and the associated vibrational processes occurring in the air, the dust particles stick together, i.e. coagulate, forming large aggregates, which greatly facilitates the subsequent purification of gases in gas purifiers. The following main factors act on particles suspended in gases under the influence of acoustic vibrations: joint oscillation of particles and a gaseous medium, dynamic forces between neighboring particles. Large particles settle down either in the sound column or enter the cavity associated with the inertial dust separator.

The optimal parameters for sound processing in an acoustic medium-dust installation are: sound pressure level in the range of 140 dB or more, oscillation frequency in the range of 900 Hz, dust concentration in the air stream at least 2 g / m ³ , dubbing time in the range of 1.5 ... 2 s. These parameters are due to the fact that, depending on the value, the suspended particle either participates in the oscillations of the medium (fully or partially) or does not participate, since the Stokes forces act on the particle and the medium. Moreover, when sound waves are passed through a volume of gas located in a closed vessel, standing sound waves are established in the latter with the formation of nodes (the oscillation velocity is zero) and antinodes in which the amplitude of the velocity oscillations is maximum. The frequency of the oscillatory process, equal to 900 Hz, creates for the dust concentration in the air stream equal to at least 2 g / m ³ such an amplitude of the sound wave at which the amplitude of the velocity of the gas particle, determined by the ratio of sound intensity (sound pressure level in the range of 140 dB and more) to the speed of sound in the medium, it will be in the antinode region of standing sound waves in a given closed vessel (acoustic column), which ultimately determines the intensity of acoustic coagulation, i.e. the rate of formation of large particles. The scoring time of 1.5 ... 2 s is assigned from the condition of formation of an antinode of standing sound waves in a given closed vessel. If the scoring time is outside the range of 1.5 ... 2 s, then this will lead to the formation of nodes in standing waves (the oscillation speed is zero) and, as a result, to weakening acoustic coagulation.

Pharmaceutical preparations derived from plants (phytochemicals) are usually obtained by dehydrating their extracts with a process that includes up to five operations — pre-cooking, drying, grinding, sieving and mixing. These drugs are often thermolabile, and therefore, when dehydrated by conventional methods, the product is of reduced quality, and often its biological activity is reduced.

In the proposed dryer, all previously required operations are combined and reduced to a single process in the apparatus 1 of the fluidized bed with an inert nozzle 10.

It is applicable for the dehydration of aqueous solutions and extracts of phytochemicals such as daucarin, marshmallow root extract, etc. At the same time, a dryer with a grate with a diameter of 400 mm provides a capacity of up to 30 kg / h on evaporated moisture. Moreover, indicators of biological activity correspond to technical conditions or are higher. The removal of the product from a unit volume of the apparatus and a unit area of the production room, respectively, is 9 and 2.5 times more than conventional spray dryers.

The use of a sufficient number of strings for each specific phytochemical preparation and the size of the dryer allows to intensify the process of abrasion of the film of materials, which ensures an increase in the productivity of the dryer.

Claims (2)

1. A suspended layer dryer with an inert nozzle, containing a heater, a fluidized bed apparatus with a distribution grid, pressure and exhaust fans, a cyclone group with a discharge device, a tank for the initial solution entering the apparatus through spray nozzles, a metering pump, and the apparatus working chamber the fluidized bed is located in its lower part and is filled with inert particles of fluoroplastic, characterized in that the aforementioned air heater is steam, while the dryer contains an electric air heater, one air filter and a measuring device for hot water for washing, an acoustic installation is installed at the inlet of the cyclone group, fluoroplastic particles are 4.5 × 4 mm in size with a working chamber height of 500 mm and a diameter of 400 mm, and elastic wire are stretched over the distribution grid of the working chamber of the apparatus strings. 2. The dryer of the suspended layer with an inert nozzle according to claim 1, characterized in that the sound pressure level in the range of 140 ... 150 dB is the parameters for sound processing in an acoustic installation of medium-fine dust with its concentration in the air stream of at least 2 g / m ³ , the frequency of the oscillatory process in the range of 800 ... 1000 Hz, the scoring time in the range of 1.5 ... 2 s.