SU603398A1 - Apparatus for conducting mass exchange processes - Google Patents

Description

The invention relates to a technique of mass transfer processes between the solid and liquid phases and can be applied in the mining, chemical, energy, food and related industries. For carrying out mass exchange processes in the field of centrifugal forces, an apparatus is known consisting of a perforated rotor and various devices for feeding and withdrawing reagents, in which the process is intensified by increasing the filtration rate of the liquid reagent under the effect of centrifugal force through the solid layer (1). The disadvantage of such an apparatus is that in the process of mass transfer in the filtering layer, not the entire surface of solid particles participates in the process, since the particles in the places of contact with each other are not washed with liquid reagent. A centrifugal apparatus is also known, in which the solid particles are created by the action of a 2J fluid. It is a hermetic stationary casing with a rotating lattice drum (rotor) located inside, which is mounted in bearing assemblies on hollow trunnions. The lattice drum is made with a hollow cylindrical container, to the bottoms of which hollow pins are fixed, and the cylindrical shell is a sieve. The suspension is introduced and withdrawn through the hollow pins of the lattice drum, and the dissolving liquid is fed into the inner cavity of the hermetic casing through a special fitting. This apparatus has a number of disadvantages that significantly affect the efficiency of the mass transfer process in the centrifugal mode. For example, liquid to supply solid particles is supplied through the orifices of the shell of a rotating drum; therefore, high local resistances occur at places where fluid enters the holes in the lattice drum, and overcoming them requires a lot of energy to create the necessary fluid pressure at the inlet of the apparatus. The fluid in such an apparatus is fed over a larger section than is output, therefore the fluid velocity increases from the periphery to the center of rotation of the drum, reaching a maximum value at the drum exit (in the hollow trunnions), which leads not to the formation of solid particles, but to the case of filtration of the fluid through a layer of solid particles, if the velocity of the liquid is small, or to the removal of the solid phase

from the apparatus, if the velocity of the liquid ensures the equilibrium of particles on the periphery of the drum under the action of centrifugal and hydrodynamic forces.

To create a soaring mode of particles, even with a negligible centrifugal force, a large consumption of dissolving liquid is needed, which must be discharged through the hollow pin of the apparatus. To reduce the removal of the solid phase from the apparatus, the velocity of the fluid through the pin should be small, and meaning that the size of the pin should be large. Increasing the size of the pin complicates the bearing and especially the gland assemblies, since due to the large local losses on the drum sieve, the pressure in the casing of the apparatus is large and can reach a value of ten atmospheres.

The purpose of the invention is to design the apparatus for conducting mass exchange processes in the field of centrifugal forces, which would ensure an efficient mass transfer process and a stable mode of solid particles with a liquid reagent flow rate at the entrance to the apparatus not larger than is necessary to carry out mass transfer only.

This is achieved by the fact that the apparatus for carrying out the process of mass transfer: s contains several working chambers narrowed to the periphery, rigidly connected to the rotor and communicating with the internal cavity of the latter directly by wide ends, the narrow ends communicate with the rotor via circulation piping; between the points of connection of the working chambers and circulation piping with the pofopoM, a screw pump is installed in its hollow part to create a circulating fluid flow inside the apparatus itself, as well as to introduce and remove products; the required mode of mass transfer process is selected by changing the speed of both the rotor and the screw pump. The process of mass transfer in individual chambers has the advantage that the rotational movement of particles relative to the rotor axis is created not by the flow of the rotating liquid, but directly by the walls of the expanding chambers, while the angular velocities of the camera and particle movements are equal. The expansion of the chamber from the periphery to the center of rotation with the liquid supply of the liquid agent to its narrow part with a speed sufficient for balancing the particles provides for obtaining greater liquid flow rates of the liquid agent to a larger radius of rotation, i.e. at high values of centrifugal force, and vice versa. This contributes to the steady mode of soiling of solid particles along the entire length of the working chambers. In this case, the flow rate of the liquid reagent at the exit from the working chambers is minimal, i.e., the possibility of carrying out the solid phase from the working chambers into the rotor cavity is significantly reduced, which increases the efficiency of mass transfer.

Circulation within the apparatus of the fluid flow necessary to create a regime

solid particles in the working chambers

apparatus, carried out by a screw pump,

combined with the rotor, helps to reduce the flow of products through the hollow

shafts, i.e. the amount of fluid entering

in the apparatus can be reduced to the value

required for the process only

mass transfer.

The drawing shows the proposed apparatus.

It contains a rotor 1, on which a tapering cone tapering to the periphery of chamber 2 and circulation pipes 3 are fixed. As the shape of the working chamber in this apparatus, a truncated cone is selected. The rotor of the apparatus is installed in the bearing assemblies 4 and is driven into rotational movement by the pinch 5. To create the circulation of the liquid reagent, serves a screw pump 6, which rotates in bearings 7 sec.

with the help of pin 8. The tightness of the withdrawal of the pump shaft 6 from the rotor 1 is provided by the gland unit 9. Products are brought in and out into the apparatus through the gland assemblies 10 and 11 and the hollow shafts of the screw pump and the apparatus rotor. A circulating liquid reagent flow is created by capturing it with a screw pump in the suction zone 12 and moving it to the injection zone 13, where it is divided into two streams. To control the reagent consumption through the apparatus, a crane 14 serves.

The machine works as follows.

The mixture of reagents containing the liquid phase, necessary only for the process of mass transfer, from the pipeline through the gland assembly 10 and the hollow shaft of the pump 6 is sucked into the rotor of the apparatus 1, where the solid phase is separated by centrifugal force, and into the cavity of the conical working chamber 2. the solid phase in the working chambers 2 is carried out by supplying the liquid reagent through the circulation pipelines 3

in the narrow part of the conical chambers. Under the action of the flow of liquid reagent particles hover throughout the volume of the working chamber until their diameter equals the diameter,

for which the value of the hydrodynamic force in the widest part of the working chamber is greater than the value of the centrifugal force. In this case, the particles are carried by the fluid flow to the suction zone 12 of the circulation pump 6, from where the latter are fed into the injection chamber 13 and through the hollow shaft of the rotor 1 are removed from the apparatus. The consumption of liquid reagent through the working chambers necessary for providing the mode of soaring of solid particles is provided by changing the number of revolutions of the shaft.

circulation pump 6 to the appropriate value. The required value of the centrifugal force and, accordingly, the necessary hydrodynamic regime is established by changing the number of rotor revolutions of the apparatus. The consumption of reagents is regulated by the crane 14

at the exit of the apparatus.