RU2626355C1 - Method of fluid medium mixing - Google Patents

Abstract

FIELD: machine engineering.

SUBSTANCE: invention is intended for intensive mixing of both mutually reactive and mutually nonreactive fluid medium with the preparation of solutions, stable emulsions or suspensions, in particular suspensions of solid particles formed during the mixed solutions reaction. The mixed media is simultaneously passed through the hydroacoustic transducer under a pressure exceeding the cavitation threshold.

EFFECT: accelerated mixing process.

1 dwg

Description

The invention relates to the food, chemical, pharmaceutical industries and is intended for intensive mixing of both mutually reacting and mutually non-reacting liquid media to obtain solutions, stable emulsions or suspensions, in particular suspensions of solid particles formed during the reaction of mixed solutions.

The goal is achieved by mixing the initial liquids supplied under pressure directly into the acoustic hydrodynamic transducer, and additional additional solutions, if necessary, enter in a regulated mode in the reduced pressure region of the acoustic resonator chambers of the hydrodynamic transducer, which generates a wide range of frequencies at the cavitation threshold value of sound pressure, including the sound range and the low-frequency region of the ultrasonic range.

The proposed method allows in the flow, in the cavitation region at the outlet of the sonar transducer, due to cavitation effects to mix immiscible liquids, to obtain suspensions of solid particles in liquids, emulsions such as water-oil, to intensify the reaction of interaction of substances dissolved in liquids and at times in comparison with the known ways to reduce energy consumption, since the coefficient of conversion of the mechanical energy of the fluid flow into the energy of acoustic vibrations is much higher than the coefficient converting electrical energy into energy of ultrasound of cavitation capacities generated by magnetostrictive or piezoceramic transducers, and the equipment used is cheaper, simpler and more durable than, for example, rotary pulsation devices (RPA), homogenizing pumps, for example, the NDG series and other similar devices.

A known method implemented using a universal hydrodynamic homogenizing dispersant for dispersing and mixing flows of liquid-phase media in order to prepare various multicomponent fluid flows used in various industries, in particular for the intensification of technological processes in the oil refining, chemical and paint industries, however, the device for implementing the method (Izotov A.V., Kozharinov V.M., Dering S.N. Universal hydrodynamic hom genizing dispersant. Patent of the Russian Federation No. 2248251, 2005), "containing sequentially installed means for providing ultrasonic treatment of the flow, each of which is made in the form of an emitter with crescent-shaped vanes having the form of part of an Archimedean spiral and joined with a cylindrical distributor, with the possibility of the formation of a vortex chamber", structurally very complex and expensive to manufacture.

A known method of mixing liquids, implemented using a cavitation mixer containing a cylindrical body with holes for supplying components and draining the medium, cowls (cavitators) placed in rows in rows perpendicular to its longitudinal axis (Akchurin R.YU. Cavitation mixer. Patent RU No. 1287928, 1984). A disadvantage of the technical device mentioned above is its low efficiency, due to the fact that only that part of the flow is proportional to the cavitation, which is proportional to the total cross-sectional area of all cavitators (fairings) installed in the cross-sectional plane of the flow chamber. The rest of the flow is not exposed to cavitation (Batchelor J. Introduction to fluid dynamics. - M .: Mir, 1973, 758 pp.).

A known method, implemented using a hydrodynamic reactor, which can be used for disinfection, homogenization and heating of liquid media, however, the design of such a reactor is not suitable for mixing fluid flows, as well as for carrying out and intensifying reactions between components of mixed flows (Dvornikov V.M. , Tyunin B.A., Galkin G.I. Hydrodynamic reactor Patent RU No. 2370707, 1986).

A known method, implemented using a hydrodynamic ultrasonic multistage mixer for use in the construction, chemical, light, food and other industries, to obtain stable finely divided multicomponent emulsions and suspensions. The mixer, however, is not intended to conduct and intensify the reactions between the components of the mixed streams (Reznikov I.D., Milrud A.G. Hydrodynamic multistage mixer. Patent RU No. 1466804, 1989).

Known cavitation reactor for mixing heterogeneous liquids with various physical properties and preparing emulsions, suspensions in the food, chemical industry, energy, etc., when mixing two or more components for the production of water-oil mixtures, oil, margarine, paper, paints, emulsions octadecylamine in water and other substances. However, it should be noted that the cavitation reactor has a complicated structure, which, moreover, is not intended for mixing various liquid media in a stream. (Savin N.G., Shalobasov I.A., Mikhailov V.A., Golubchikov V.M., Volkov E.P. Cavitation reactor. Patent RU No. 2016646, 1994).

There is a method of preparing vodka (Kochetov A.A., Antonov V.M., Ivanov O.M., Avdeeva G.I., Puchkov V.V., Shibunya BC, Sarukhanov R.G. Method for the preparation of vodka. RF patent № 2250256, 2005), mixing liquid components in a cavitation acoustic field of hydrodynamic transducers. The individual components of the final product are fed into a mixing tank, after which the injection pump is turned on to feed the mixture into sonar transducers and into the circulation system, and the drain pipe is closed. During the operation of hydroacoustic transducers (Ponomarev V.G., Smirnov V.F., Sarukhanov R.G., Smirnova N.L. Hydrodynamic transducer. Patent SU No. 1131553, 1983), alternating pressures arise in the voiced volume of the mixture, causing secondary effects (cavitation, pulsation, oscillation and micro-macro flows), which contribute to the intensive dispersion and homogenization of the product.

Numerous designs of rotary pulsation apparatuses are known, which are very successfully used for mixing liquids, emulsifying, dispersing (Ivanets G.E., Plotnikov V.A., Safonova E.A., Artemasov V.V., Kostenko E.A., Zverev V.P. Rotor-pulsation apparatus with a vibrating rotor.Patent RU No. 2203728, 2003; Bogdanov V.V., Britov V.P., Kim V.V., Klotsung B.A., Smirnov B.L., Shkurin K.A., Rotary-pulsation apparatus, Patent RU No. 2056154, 1996, Smolyanov, V.M., Novoseltsev, D.V., Filippov, I.A., Zhuravlev, A.V. Rotary-pulsation apparatus, Patent, RU 2335337, 2008, and row other gih). A common design feature of rotary pulsation apparatuses is the presence of rotating parts located at a certain distance (usually measured in fractions of a millimeter) from each other. A common drawback is the rapid wear of the elements of the rotating parts, during the interaction of which with the liquid phase in the latter there is the phenomenon of cavitation. Wear is significantly accelerated when processing suspensions containing solid particles, as well as during the formation of suspensions of solid particles as a result of a chemical reaction between the components of the mixed solutions.

Known, for example, is a method for the synthesis of hydroxyapatite in a hydrodynamic disperser of a rotor-pulsation type (Gorshenev V.N., Teleshev A.T., Ershov Yu.A., Kaziev GZ, Kolesov VV, Sklyanchuk E.D. A method of obtaining a porous bone biocomposite. Patent RU 2482880, 2013), adopted as a prototype. The method reflects all the negative properties inherent in the methods using rotary pulsation apparatuses.

The proposed method for mixing liquid media is characterized in that the mixed liquids under the same pressure of 34⋅10 ³ ÷ 5⋅10 ⁵ Pa are supplied simultaneously through dosing devices to the sonar transducer, with characteristic sizes of 2-4 cm, from where they reach the cavitation area in tenths of a second behind the transducer, where the phenomena accompanying cavitation are shock waves and microflows with high velocity gradients that minimize diffusion limitations (Akopyan V.B., Ershov Yu.A. Fundamentals of the interaction of ultrasound with b and biological objects. - M.: URIGHT, 2016, 223 S.), accelerate the chemical reactions of the interaction of the components of the mixed liquids. The resonator chambers of the hydrodynamic converter, where a reduced pressure is created, allow additionally, if necessary, to introduce into the flow solutions of substances mixed with the main fluid stream. In addition, in the reaction of solutions to obtain a suspension of solid particles, in particular hydroxyappatite from aqueous solutions, by reaction

10Ca (NO ₃ ) ₂ +6 (NH ₄ ) ₂ HPO ₄ + 8NH ₄ OH = Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ + 20NH ₄ NO ₃ + 6H ₂ O,

solid particles are formed mainly in the cavitation field outside the ultrasonic hydrodynamic mixer and do not cause cavitation erosion and accelerated mechanical wear of its surfaces.

To implement the claimed method, as a source of acoustic vibrations, creating a field of a continuous wide spectrum of frequencies in the range from 1 to 45 kHz, a hydroacoustic transducer with two resonator chambers is used, which differs from the well-known one in that the mixed liquids are simultaneously supplied under the same pressure 34⋅10 ³ ÷ 5⋅10 ⁵ Pa through dosing devices to the input of a sonar transducer emitting acoustic vibrations in the frequency range 1 ÷ 45 kHz and in the range of power densities aku static field 0.1 ÷ 0.3 W / cm ³ .

The analysis of the prior art of mixing two or more liquid media, characterized by features identical to all the essential features of the invention, is not found, therefore, the invention satisfies the condition of "novelty."

An additional search for known solutions showed that the invention does not follow explicitly from the prior art for a specialist, since the proposed method uses acoustic exposure in the field of a continuous wide spectrum of frequencies, among which there always exist frequencies resonant with the natural frequencies of gas cavitation bubbles of various sizes, from which that the invention meets the condition of "inventive step".

The technical implementation of the invention is illustrated by the following examples, which are not, however, of a limiting nature.

Example 1 (prototype, in the best case)

Synthesis of hydroxyapatite (HAP) by a condensation method using a rotary pulsation apparatus (RPA) by reaction

6CaHPO ₄ ⋅H ₂ O + 4Ca (OH) ₂ → Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ + 12H ₂ O

carried out as follows:

- loaded into the buffer tank RPA 5 l of distilled water;

- they started the engine and brought the speed to 1500 min ^-1 ;

- 700 g of calcium monophosphate hydrate were loaded into the RPA buffer tank;

- brought the engine to operating mode (3000 min ^-1 ) and kept the solution for 2 min at 35 ° C;

- a suspension of 178 g of calcium hydroxide in 6 l of water was gradually introduced into the buffer tank of the RPA gradually at a speed of 1 l / min;

- after adding calcium hydroxide, the reaction mixture was treated for 20 min at a temperature of 70 ° C.

During the synthesis of hydroxyapatite, the pH value decreased from 10.8 to 6.3. The white, homogeneous, mobile suspension obtained during the synthesis of hydroxyapatite was sent to a vacuum filter, after which the retenate was washed with hot water. Yield 94%. The duration of the HAP synthesis process by the described method> 20 min.

Example 2 (by the proposed method in the best case)

Synthesis of hydroxyapatite by condensation using a sonar transducer by reaction

6CaHPO ₄ ⋅H ₂ O + 4Ca (OH) ₂ → Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ + 12H ₂ O

carried out as follows:

- at the inputs (1) of the hydroacoustic transducer (5), through flow rate control valves (2), at room temperature, under a pressure of 4⋅10 ⁵ Pa above the cavitation threshold, an aqueous solution of calcium monophosphate hydrate with a concentration of 149 g / l and a suspension of calcium hydroxide with a concentration of 29.7 g / l;

- input (3), through which, if necessary, additional substances (colorants, catalysts, flavorings, etc.) can be supplied, is not used in this example;

- from the output (4) of the hydroacoustic transducer (5), the finished product through an intermediate buffer tank was supplied to a standard separation system (vacuum filter, flow centrifuge or another). The pH of the suspension of the finished product - hydroxyapatite before the separation system is not more than 6.3. The yield of the finished product is ~ 94%. The duration of the HAP synthesis process by the proposed method <0.5 min.

From the analysis of the above results it follows that the proposed method allows the synthesis of HAP ~ 40 times faster than using RPA. This result makes it possible to design a continuous process for the synthesis of HAP with its subsequent isolation and targeted use.

Thus, the technical result of the claimed method is to accelerate the process of mixing and interaction of liquids in the field of a hydrodynamic ultrasonic mixer by the example of HAP synthesis to values that allow us to approach the design of a continuous production process,

Additional studies on the variation of various physical parameters of the process (pressure, temperature, fundamental frequency, pulse mode) in the search for optimal HAP synthesis modes showed that when each of these parameters changes, both increase and decrease (with the remaining parameters being constant) reduced the rate of interaction of mixed liquids by the example of HAP synthesis by 15–45%.

For the claimed method in the form as described in the claims, there are no obstacles to its implementation in practice using modern technical means. Therefore, the invention meets the condition of "Industrial applicability".

Claims (1)

A method of mixing liquid media, characterized in that the mixed medium is passed simultaneously through a sonar transducer under pressure exceeding the cavitation threshold.

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