RU2316702C1 - Apparatus for air-lift drying without particle entrainment - Google Patents

Abstract

FIELD: microbiological, food, chemical and other industry, particularly dispersed material drying.

SUBSTANCE: apparatus comprises drying chamber and hopper. Drying chamber comprises cylindrical body and porous shell concentrically arranged in the body. Shell is produced of material based on aluminum-containing alloys with following alloy filling with titanium hydride or air having density of 0.5-0.9 kg/m³ with the following strength properties: compression strength is 5-10 MPa, bending strength is 10-20 MPa. To remove drying agent from shell rotary hollow cylinder is provided. Hollow cylinder is formed of rigid porous material with 30-45% porosity. Wet material is supplied through several sprayers uniformly distributed over total shell section. Acoustic device connected with cyclone means is installed at apparatus outlet. Acoustic device provides acoustic treatment of material with particle content of at least 2 g/m³ in air flow with the following parameters: sound level is 145-150 dB, oscillation frequency is 900-1100 Hz, sounding time is 1.0-2 sec.

EFFECT: increased drying capacity.

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 technical solution for A. with. SU 848928, F26B 3/12, 07/23/1981, containing a wet material loading device, a drying chamber, a fan, a lock, a hopper, a top cover, while the dry product is removed from the hopper through a lock and the drying agent leaves the unit through space under the top cover.

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 apparatus for suspension-free drying in suspension contains a loading device of wet material, a drying chamber, a fan, a lock gate, a hopper, a top cover, while the dry product is removed from the hopper through a lock gate, and the drying agent leaves the apparatus through space under the top cover. The drying chamber comprises a cylindrical body, a porous shell coaxially located therein, forming a space for uniform passage of the drying agent into the shell. The shell material is made on the basis of aluminum-containing alloys, followed by filling them with titanium hydride or air with a density in the range of 0.5 ... 0.9 kg / m ³ with the following strength properties: compressive strength in the range of 5 ... 10 MPa, strength bending within 10 ... 20 MPa. To remove the drying agent from the shell, a rotating hollow porous cylinder is provided, connected by a shaft with a drive located on the cover, the porous cylinder made of rigid porous material, for example, foam aluminum or cermet, or metal foam with a degree of porosity in the range of optimal values: 30. ..45%. The supply of wet material or solution is carried out by several nozzles, evenly spaced throughout the cross-section of the shell. At the outlet of the apparatus, an acoustic installation for collecting fine particles connected to a cyclone connected to an unloading device is installed, while the parameters for sound processing in an acoustic installation with a particle concentration in the air stream of at least 2 g / m ³ are: sound pressure level in the range of 145 ... 150 dB, the frequency of the oscillatory process in the range of 900 ... 1100 Hz, the dubbing time in the range of 1.0 ... 2 s.

The drawing shows a diagram of an apparatus for non-weighted drying in suspension.

The apparatus for suspension-free drying in suspension contains a cylindrical body 1, a porous shell 2 coaxially located therein, forming a free space for uniform passage of the drying agent into the shell. The material of the shell 2 is made on the basis of aluminum-containing alloys, followed by filling them with titanium hydride or air with a density in the range of 0.5 ... 0.9 kg / m ³ with the following strength properties: compressive strength in the range of 5 ... 10 MPa, bending strength within 10 ... 20 MPa.

The dimensions of the annular space are determined by the performance of the drying unit and the quantitative characteristics of the initial dispersed material, for example, the size and shape of the particles, particle size distribution, density, structural properties, etc. Dry product is removed from the hopper 7 through the lock gate 8. To remove the drying agent from the shell 2, a rotating hollow porous cylinder 3 is provided, connected via a shaft 4 to a drive (not shown in the drawing) located on the cover 5. The hollow porous cylinder 3 is made of a rigid porous material, for example foam aluminum or cermets, or metal foam with a degree of porosity in the range of optimal values: 30 ... 45%.

Depending on the performance of the chamber in an industrial environment, the supply of wet material or solution can be carried out by several nozzles 6, evenly spaced throughout the cross section of the shell 2.

The coolant through the space under the top cover 5 leaves the apparatus at the output of which an acoustic installation is installed (not shown in the drawing) for trapping medium-sized particles connected to a cyclone connected to a discharge device (not shown in the drawing). The optimal parameters for sound processing in an acoustic installation with a particle concentration in the air stream of at least 2 g / m ³ are: sound pressure level in the range of 145 ... 150 dB, oscillation process frequency in the range of 900 ... 1100 Hz, sound time in range 1.0 ... 2 s.

The apparatus for non-weighted drying in suspension is as follows.

A drying agent with a predetermined temperature and humidity enters the free space between the walls of the housing 1 and the shell 2. Under the action of pressure created, for example, by a fan, the drying agent penetrates through the pores of the walls of the shell, heat and mass transfer between the gas and drops or particles occurs, continuously supplied through the atomizer 6. The settling of drops or particles on the walls of the shell is prevented by organized blowing them from the walls of the drying agent entering through the pores. The spent coolant passes through the pores of the rotating hollow porous cylinder 3, and particles approaching the surface of the cylinder fall into the rotating boundary layer that forms near its surface, and under the action of centrifugal forces are again discarded into the shell volume and removed from the apparatus. The coolant separated from the particles leaves the apparatus through the space under the top cover 5.

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 drying agent, since under the influence of the sound field and the associated vibrational processes occurring in the air, 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: the joint oscillation of particles and the gas 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 the formation of an antinode of standing sound waves in a given closed vessel. If the dubbing 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.

One of the most effective ways to prevent harmful emissions from entering the environment is to use closed cycles of a gas agent when drying various materials.

The proposed apparatus provides a significant reduction in particle emission.

Claims (1)

The suspension-free drying apparatus containing a wet material loading device, a drying chamber, a fan, a lock gate, a hopper, a top cover, while the dry product is removed from the hopper through a lock gate, and the drying agent leaves the machine through the space under the top cover, characterized in that the drying chamber comprises a cylindrical body, a porous shell coaxially located therein, forming a space for uniform passage of the drying agent into the interior gulls, wherein the shell material is formed on the basis alyuminesoderzhaschih alloys followed by filling them with air or titanium hydride having a density in the range of 0.5 ... 0.9 kg / m ³ with the following strength properties: compressive strength in the range of 5 ... 10 MPa, bending strength within 10 ... 20 MPa, moreover, to remove the drying agent from the shell, a rotating hollow porous cylinder is provided, connected by a shaft with a drive located on the cover, and the porous cylinder is made of rigid porous material, for example, foam aluminum or ceramic, or metal foam with a degree of porosity that is in the range of optimal values of 30 ... 45%, while the supply of wet material or solution is carried out by several sprays evenly distributed over the entire cross-section of the shell, an acoustic unit is installed at the outlet of the apparatus for collecting medium-sized particles connected to the cyclone associated with the device for unloading, while the parameters for sound processing in an acoustic installation with a concentration of particles in the air stream not m with about 2 g / m ³ are the sound pressure level in the range of 145 ... 150 dB, the frequency of the oscillation process in the range of 900 ... 1100 Hz, while scoring in the range 1.0 ... 2 seconds.