FI81274C - FOERFARANDE OCH ANORDNING FOER BLANDNING AV ETT HETEROGENT MEDIUM. - Google Patents

Description

! 81274

The present invention relates to a method for mixing a heterogeneous medium and to an apparatus for applying this method.

The invention can be applied in the chemical industry, for example in the production of mineral fertilizers, in microbiology in the production of yeast products, in the petrochemical industry, in medicine and elsewhere.

10 Equipment for mixing heterogeneous substances is already known, for example equipment with agitators (cf. F. Streng, "Peremeshivanie i apparaty s meshalkami", in Russian, Khimia Publishing House, Leningrad, 1975, p. 384).

Such a device has a housing with nipples for feeding and discharging the material phases, and the inner part of the housing forms a vessel with a shaft and a mixer. The shaft is connected in a reduction gear to an electric motor which rotates it. A flange seal is provided at the point where the shaft enters the housing.

The shaft comprising the agitator rotates via a reduction gear by means of a motor. The heterogeneous substance is mixed in this way, whereby the heat and mass transfer process through the phase interface is accelerated.

However, a device of the above-mentioned type may not provide a sufficient rate of heat and mass transfer to heterogeneous materials, and in addition they consume too much operating energy, which in turn reduces their efficiency.

Vulnerable parts, such as the reduction gear and flange seals, also reduce the reliability of the device.

In addition, such a device cannot be made sufficiently pressure-tight or sterile, so its use in industry is limited.

2 81274

In addition, a method of mixing a heterogeneous substance is known, which involves mixing the substance and subjecting it to intermittent oscillations of varying frequency (cf. the inventor's certificate SU No. 508,400, IPC B 01 F 5 11/00, published 1971).

This method is also disadvantageous because it does not provide rapid heat and mass transfer and requires a lot of power for mixing.

Also known is a vibration remover (cf. the inventor's 10 certificate SU No. 697 139, Int. Cl. B 01 D 11/00, published November 15, 1979), which has a housing comprising nipples for feeding and removing liquid phases and a vessel with a rod comprising plate elements, connected to the vibration drive and equipped with a disintegration device. 15 The plates comprising the rod move back and forth by means of a vibration drive and mix the heterogeneous substance.

Because all the plates are attached to the rod, they apply vibrations to the heterogeneous material in one phase. Therefore, the housing of the vibration remover is subjected to appreciable dynamic loads, which cause appreciable vibrations.

Overpressure and underpressure zones are created between two adjacent plates, which weaken each other, resulting in a decrease in the rate of heat and mass transfer in the heterogeneous material.

Another device for mixing a heterogeneous substance is described in the inventor's certificate SU 401 385, Int. Cl. B 01 F 11/00. This device comprises a housing with nipples for feeding and discharging the substance phases and a vessel with a rod comprising mixing elements and a sealing unit between the housing and the rod. The mixing elements are convex concave pins. Attached to the housing is an electromagnetic vibrator having a coil whose sheath is connected to the rod and moves it 35 axially in the housing.

n 3 81274

The device works as follows.

The rod and thus also the rod comprising the mixing parts perform reciprocating movements under the action of an alternating electromagnetic field at a predetermined frequency. The reciprocating movements of the mixing elements mobilize the heterogeneous substance so that it is subjected to intermittent mechanical vibrations in one step.

One of the disadvantages of such a device and the mixing method associated with its use is its low heat and mass transfer rate due to the application of mechanical single-phase vibrations to the heterogeneous material. The device does not provide conditions that are favorable for homogenizing the heterogeneous material in the housing container. The device is also subject to significant vibrations.

In addition, the sealing unit is not able to protect the inside of the electromagnetic vibrator from gases and vapors of the heterogeneous substance to be mixed.

The present invention relates to a method of mixing a heterogeneous substance which provides suitable conditions for mixing the substance and subjecting it to intermittent mechanical vibration and to developing the device so that the method can be applied by providing additional elements in its electromagnetic vibrator to facilitate heat and mass transfer process and to reduce the power consumed for its use and at the same time reduce the vibrations of the device housing.

This problem is solved by a method of mixing a heterogeneous substance by mobilizing the substance and applying intermittent mechanical vibrations to it, wherein according to the invention intermittent mechanical vibrations are directed to the heterogeneous substance by two adjacent sources of such vibrations in a phase of 0.5 to 10.0 mm.

4,81274 In the present method, strong mechanical vibrations on a heterogeneous substance produce a physical effect, as noted by the present inventors, entitled "Increasing the mutual velocity vibration of the particles dispersed in a liquid". This effect is fully utilized in the proposed method, which promotes the process of heat and mass transfer through the phase interface and causes the decomposed particles to be distributed more uniformly in the vessel of the device.

10 A stronger mixing process also ensures a more efficient use of the raw material, improves the quality of the product and significantly reduces the amount of power used in the process.

In order to enhance the mixing, the substance is mixed with the average so that its average flow rate is 1- to 4 times the settling rate of the disintegrated particles.

This problem is also solved by a heterogeneous substance mixing device with a housing provided with nipples for feeding and discharging the substance phases, and a vessel with a rod with mixing elements which enters the housing and is closed by a sealing unit, and an electromagnetic vibrator mounted in the housing. a coil having a jacket connected to a rigid box rod and moving in the rod on the longitudinal axis of the housing, said device basin comprising at least one additional rod comprising mixing elements, while the electromagnetic oscillator is provided with at least one additional winding rigidly connected to the other rod 30 its movement in a direction opposite to the direction of movement of the first rod, the windings being arranged coaxially on a common base on its opposite sides and electrically connected accordingly.

5,81274

Due to such an arrangement of the device, it is possible to use practically all the vibration speeds and accelerations required in the intensification processes when there are no so-called damaging vibrations.

5 Therefore, the proposed device is more efficient and reliable, as it has no rotating or abrasive parts.

To streamline the mixing process, the device is preferably provided with two rods, one of which is hollow, arranged coaxially in the vessel, or alternatively three rods, two of which are arranged in the vessel on opposite sides of the first rod and rigidly connected to the second jacket.

In order to carry out the mixing processes caused by the formation of foam, it is recommended that the device be provided with foam barrier plates which are firmly attached to the rods.

It is preferred that the sealing unit is provided with at least one resilient element made of a circular plate with through-going, curved openings arranged concentrically and holes with a rod in order to ensure complete pressure tightness of the working vessel of the device.

In order to ensure a more reliable pressure tightness of the work vessel at high pressures, the sealing unit is preferably provided with two flexible elements shaped as round plates fixed so that their holes 25 move relative to each other.

To streamline the mixing processes, the mixing element is preferably a plate with nozzles shaped into truncated cones with a smaller base facing the plates.

30 The proposed method for mixing a heterogeneous substance is based on mixing the substance to homogenize it to ensure optimal conditions. During such mixing, the solid particles remain floating due to the movement of the liquid. At the same time, 6,81274 intermittent mechanical oscillations are applied to the fluid moving in this way from two adjacent sources of such oscillations in opposite phases with an amplitude of 0.5 to 10 mm. The vibrations cause the vibration motion of the liquid particles. In the motion of a vibration-5 of a liquid having solid particles having a density different from the density of the liquid, these solid particles are in motion with respect to the liquid in which they are due to inertial forces. The movement of solids relative to the liquid again promotes sequential diffusion through the phase interface 10, resulting in enhanced heat and mass transfer processes.

The oscillating motion of the liquid droplets and bubbles in the eddy flow corresponds to that described above.

When the oscillations are applied with an amplitude Ia of less than 0.5 mm, the heterogeneous material is not made sufficiently homogeneous, whereas with this amplitude greater than 10 mm, a significantly higher amount of power is consumed for the process and the mixing process is only slightly more efficient.

The inventors have found that the effect of the increase in the vibration of the relative velocity of the particles dispersed in the liquid is fully utilized in the proposed mixing method. This effect facilitates heat and mass transfer processes with minimal energy consumption.

The application of intermittent mechanical vibrations allows the mixing of the heterogeneous substance in the mixing process with a minimum of power. Stirring can continue at an average flow rate of 1 to 4 times the settling rate of the decomposed particles.

The application of the method according to the invention 30 will be described below as specific examples.

li 7 8Ί274

Example 1

In an apparatus with a work vessel of 1 m 2, an electrochemical reduction process of copper is carried out in a sulfuric acid solution with the following physical properties of the heterogeneous substance to be mixed with zinc powder: liquid density 1000 kg / m, liquid viscosity -3 3 10 kg / (ms), density of solid particles 2000 kg / m, diameter of solid particles 0.1 mm. The torn plates are used to mix the substance and subject it to mechanical vibrations. Each pair of plates performs oscillations as a counter-phase.

Table 1 below shows the process parameters of the proposed method and the method according to the inventor's certificate SU No. 508 400.

15 Table 1

Process parameters Proposed according to the present inventor's certificate - according to its SU No. 508 400_ 20 Frequency of oscillations, Hz 50 8

Amplitude of plate vibrations, mm 2 30

25 power consumed by the plate, kW 1 4

Particle settling rate, m / s 0.1 0.1

Average flow rate, m / s 0.35 0.35 30 Process speed, kg / (m3s) 16.7-10-3 16.5-10-3

Specific power consumption for copper reduction, J / kg 0.6-10 ** 2.4 * 10 ** β 81274

Example 2

In an apparatus with a working vessel of 1 m 2 volume, an oxidation process is carried out on an aqueous sodium sulfite solution without the oxygen-miscible heterogeneous substance having the following physical properties: liquid density 1000 kg / m, liquid viscosity -3 3 10 kg / (ms), air density 1.29 kg / m.

The heterogeneous material is mixed by feeding compressed air through a diffuser, while intermittent mechanical oscillations are produced by perforated plates. Each pair of plates vibrates in the opposite phase.

Table 2 below shows the process parameters according to the proposed method and the inventor's certificate SU No. 508,400.

15 Table 2

No. Process parameters Method

Proposed Inventor of the Inventor's Proof According to SU No. _508 400 20 J___2_3__4_ 1 Frequency of oscillations, Hz 10 8 2 Amplitude of oscillations, mm 10 30 3 Power consumed by the plate, kW 0.7 3.5 4 Air consumption, m ^ / s 1.66 * 10 ^ 1.66 * 10 ^ 25 5 Bubble buoyancy rate, m / s 0.19 0.19 6 Average flow rate, m / s 0.58 1.16 7 Oxidation rate, m ^ C ^ / ( m3s) 23.5 * 10 4 23.5'10 4 8 Specific power consumption for oxidation, J / m ^ 0.5 * 10® 1.48 * 10®

Example 3 3

In an apparatus with a work vessel of 1 m capacity, the oxidation process of the aqueous sodium sulphate solution is carried out without the oxygen-miscible heterogeneous material. The physical properties of the substance are as follows: 3 -3 liquid density 1000 kg / m, liquid viscosity 10 kg / (ms), 3 air density 1.29 kg / m.

9 81274

The heterogeneous material is mixed by feeding compressed air through a diffuser, while intermittent oscillations are provided by perforated plates. Each pair of plates oscillates in phase.

5 Table 3 below shows the process parameters of the proposed method and the method according to the inventor's certificate SU No. 508 400.

Table 3

Process parameters Method

According to the invention of the inventor's certificate, the frequency of the oscillations, Hz 600 8, the amplitude of the oscillations, mm 0.5 30

Power consumed by the plate, kW 1.2 3.5

Air consumption, m3 / s 1.66 * 10 ^ 1.66 * 10 3

Bubble floating speed, m / s 0.19 0.19

Average flow rate, m / s 0.70 1.16

Oxidation rate, m302 / m3s 23.5-10-4 23.5-10-4 25 Specific power consumption for oxidation, J / m3 0.5-106 1.48 * 106

The invention will be described in detail with reference to the special structures of the proposed device shown in the accompanying drawings, in which Figure 1 is a longitudinal section of a proposed device for mixing a heterogeneous device with two rods, Figure 2 is a longitudinal section of a second variant of the proposed device; longitudinal section of the plate nozzle, Fig. 4 is an enlarged section of the sealing unit, and Fig. 5 is an enlarged plan view of the elastic part of the device 5 according to the invention.

The following describes the apparatus used to apply the proposed method.

The proposed device for mixing a heterogeneous substance (Fig. 1) comprises a housing 1 with connections 10 2 and a connection 3 for feeding and discharging the substance phases, respectively. The assembly 1 has a container 4 with rods 5 and 6, of which rod 5 is hollow, said rods being arranged coaxially.

The number of bars comprising the mixing elements is determined by the parameters of the mixing process. Normally, a device comprising two rods 5 and 6 has a small-volume vessel 4 which is used in laboratories and small establishments.

The device-20 having a container 4 with a larger volume may have three rods 7, 8, 9 (Fig. 2), of which the rods 7 and 9 are preferably arranged on the sides of the rod 8. Such a device is preferably recommended for large production plants.

Mounted in the housing 1 is an electromagnetic vibrator 25 having at least two windings 10 and 11 with anchors 12 and 13. The windings 10 and 11 are coaxially arranged on a common base 14 on opposite sides thereof and connected accordingly. The number of windings determines the power of the preselected electromagnetic oscillator depending on the required stirring power. Generally, for small containers, two coils 10 and 11 are used. The anchor 12 is rigidly attached to the mounting plate 15, while the anchor 13 is fixed to the mounting plate 16, respectively. Elastic parts are arranged between the plates 15 and 16 and the common base 14, e.g. 17.

il n 81274

The jacket 12 is rigidly connected to the rod 5 by a mounting plate 15 to ensure its axial movement relative to the housing 1. The anchor 13 is rigidly connected by a mounting plate 16 to the rod 6 to ensure its movement axially with respect to the co-roll 1 in a direction opposite to the direction of movement of the rod. However, as shown in Fig. 2, the anchor 13 can be rigidly connected by the mounting plate 16 to the two rods 7 and 9 to ensure their movement axially with respect to the housing 1 in the opposite direction to the movement of the rod 8. 10 This arrangement makes it possible to speed up the mixing process and thus increase the efficiency of the device. The rods 7, 8 and 9 are rigidly connected to the mixing elements, which are in the form of torn plates 18. In order to improve the mixing, the nozzles 19 can be placed in the holes of the plates 18. Each such nozzle 19 is formed into a truncated cone, and its smaller base goes over the plate 18. The proposed device can therefore be used advantageously in processes involving the formation of a permanent foam, such as in microbiology. To this end, the rods 7, 8 and 9 (Fig. 2) 20 are placed considerably above the heterogeneous substance to be mixed in the foaming zone with two torn plates 20. The foam falls when it is brought into contact with the vibrating surface of the plate 20 and compresses the space between the plates.

At the point where the rods enter the housing of the device, a sealing unit with at least one elastic and one flexible element 21, 22 is placed (Fig. 4). These two elements ensure the pressure tightness of the housing 1. The elastic element 21 is made in one piece and made of fluoro-30 plastic, rubber or metal depending on the process conditions. This element 21 is tightly pressed into the housing 1 and the rod 5 by a flexible element 22. The elastic element 21 and the flexible element 22 are placed in the collar 23 of the rod 5 and fastened from above by a nut 24; the other bars 35 7, 8 and 9 are press-sealed in the same way. The flexible element 22 81 274 is made of spring steel and is in the form of a round plate with through, curved, concentric openings 25 (Fig. 5). The openings 25 ensure its rigidity, while its central part can move vertically to its circumference. The flexible part 22 has a certain rigidity, and the number of such elements to be used depends on the overpressure in the container 4 of the housing 1. An elastic element 21 is interposed between each pair of flexible elements 22. If the sealing unit has a plurality of flexible elements 22, the openings 25 of one flexible element are offset relative to the openings 25 of the other element. Such an arrangement of the flexible elements 22 in the sealing unit guarantees a reliable pressure tightness of the container 4 when the pressures are considerable. The housing 1 of the proposed device may have one 26 for removing gases formed during the mixing process.

The device according to the invention operates as follows: The heterogeneous substance is fed together via 2 into the container 4 of the housing I. The windings 10 and 11 of the electromagnetic oscillator are connected in a uniform manner. To do this, an AC voltage is applied to the mains. The current of the coil causes the mutual attraction of the anchors 12, 13 and the coils 10 and 11, respectively, to pull them together and change the shape of the springs 17. The opposite movement is effected during the forward movement of the springs 17 by storing the potential-25 with energy. After this, the cycle repeats. However, during the phase operation, the anchors 12, 13 of the electromagnetic oscillator move in opposite directions, which is determined by the placement of the windings 10, II. The anchor 12 ensures the movement of the rod 5 or 8 with the mixing plates 18 in the longitudinal direction of the housing 1, while the anchor 13 moves the rod 6 (or 7, 9) with the mixing plates 18 in the opposite direction to the movement path of the rod 5 (or 8). The plates 18 are made to perform reciprocating motions so as to provide a progressive and oscillating motion to the heterogeneous material, which promotes flow. The average flow rate 35 is brought to a level that is 1 to 4 times the settling rate of the halide 13 81 274 particles. At the same time, intermittent mechanical vibrations with an amplitude of 0.5 to 10 mm are applied to the flow.

When similar masses are connected to the sheaths and when the liquid applies similar resistance values to the movement of the plates 18 (this factor is more important of the two), the sheaths 12, 13 and thus the plates 18 oscillate in opposite directions with similar amplitudes. The common base 14 and the coils 10, 11 of the electromagnetic oscillator do not oscillate. 10 The movements described above are balanced due to the similarity of the electromagnetic forces acting in opposite directions.

On the basis of the above, it can be stated that the electromagnetic oscillator is designed so that it can only vibrate the active masses of the anchors 12, 13 with the rods 5, 6 or 7, 8, 9 and the plates 18, whereby reactive masses are not required. For this reason, the electromagnetic oscillator is compact and light, while the springs 17 stretch only according to the amplitude of the oscillations amp-20 of the active masses. The springs therefore have a sufficiently long service life, so that they last for several years in continuous use.

The heterogeneous material fed together 2 through the housing 1 into the vessel 4 first enters the working area of the first pair of mixing plates 18 oscillating in opposite directions. After the substance to be mixed has passed several times through the circulation circuit of the first pair of plates 18, the substance is progressively ejected by the inflow of heterogeneous substance and enters the working areas of the second pairs of mixing plates 18. Once the heterogeneous substance has circulated in these regions, it leaves the vessel 4 of the housing 1 via the nipple 3. . plates 18 which oscillate in opposite directions are more advantageous hydrodynamically than those plates which oscillate in only one direction (namely, when they are in only one rod) because the pressure fields between the two 14 81 274 plates are combined so that the plates 18 The flow of liquid through the nozzles 19 is increased. Mixing is further enhanced due to the special shape of the nozzles 19.

5 When, after mixing, foam begins to form, this tends to float on the surface and accumulate on the surface of the heterogeneous substance, i.e. the plates 20 in the working area of the blocking foam. In this case, during the half-cycle, when the paired plates 20 detach from each other, a certain vacuum is created in the space between the plates 10 with respect to the working pressure in the housing 1, whereby foam is absorbed into the space between the plates by the holes in the plates 20 and the side openings between them. Thus, as the plates 20 move back during the next half cycle, the space between the plates decreases, and during compression 15, the foam breaks. The liquid flows downwards, while the gas flows upwards and comes out of the joint 26. The cycle then repeats.

It is clear that some of the foam passes back through the holes and the side opening of the plate during compression.

However, experience has shown that in such pi-20 flow processes, such as the removal of foam by vibrations, the volume fraction of the foam expelled is negligible.

Il

Claims (7)

1K 81274 15 An apparatus for mixing a heterogeneous substance, the apparatus comprising a housing (1) having pipe sections 5 (2,3) for feeding and discharging the substance phases, a vessel (4) having a rod (5) comprising mixing elements in the housing (1) and surrounded by a sealing unit, and an electromagnetic oscillator attached to the housing (1) and comprising a winding (10) with an anchor (12) rigidly connected to the rod (5) for moving the rod (5) along the longitudinal axis of the housing (1), characterized in (4) has at least one additional rod (6) with mixing elements, while the electromagnetic oscillator is provided with at least one additional winding (11), the anchor 15 (13) of which is rigidly connected to the rod (6) and ensures its movement in the direction of movement of the rod (5) in the opposite direction, the windings (10, 11) being arranged coaxially on a common base (14) on opposite sides thereof and electrically connected in a corresponding manner. Device according to Claim 1, characterized in that, in the case of two rods (5, 6), the second rod (5) is hollow and both rods are arranged coaxially in the vessel (4). Device according to claim 1, characterized in that in the case of three rods (7,8,9) two rods (7,9) are arranged in the container (4) on opposite sides of the third rod (8) and rigidly attached to the anchor (13). ). Device according to Claim 3, characterized in that it is provided with plates (20) rigidly attached to the rods (7, 8, 9) for damping the foam. Device according to claim 1, characterized in that the sealing unit is provided with at least one flexible element (22) made in the form of a circular plate 81274 with through-going, curved concentric openings (25), with a rod passing through each hole . Device according to Claim 5, characterized in that, when the sealing unit is provided with two flexible elements (22) in the form of round plates, they are fastened so that their openings (25) are displaced relative to one another. Device according to one of Claims 1 to 6, characterized in that the mixing element is formed by a plate (18) with nozzles (19) having the shape of truncated cones, the smaller base of which extends above the plate (18). 17 81 274