RU2422198C1 - Method of sonochemical treatment of water solution for biopolymer hydration - Google Patents

Abstract

FIELD: process engineering. ^ SUBSTANCE: invention relates to sonochemical treatment of fluids and may be used in water solution biopolymers hydration to produce components of medicine preparations, food products, semi finished products and raw materials. In compliance with proposed method, solutions are treated in cavitation reactor with preset amplitude of pressure of ultrasound fed into reactor and at preset efficiency at no higher than +60C. Note here that, for treatment of water volume defined by disclosed formula, no more than one mega joule of ultra sound power is consumed. Note also that ultra sound is radiated at pressure amplitude with relation to hydrostatic pressure in reactor taken to make 1<a<5.5. ^ EFFECT: reduced power consumption, higher efficiency. ^ 3 dwg, 1 tbl

Description

The invention relates to the field of sonochemical processing of liquid media, where the energy performing useful work is transferred via the epithermal route with virtually no increase in the temperature of the whole medium [1], which is characteristic of high-energy chemistry. The influencing factor in this case is the pressure pulses emitted by cavitation bubbles pulsating in the medium under the action of ultrasound emitted therein when they are compressed to a volume smaller than the so-called resting volume, which corresponds to hydrostatic pressure in the medium, and small heat losses occur only due to internal friction in her.

The preferred field of application of the invention is the treatment of aqueous solutions used for hydration of biopolymers with the aim of isothermal destruction of molecular associates of water formed by hydrogen bonds [2, 3] and hydration shells in a solution of ions and colloids. In this case, the water in the solution for some time is removed from the state of thermodynamic equilibrium and goes into a state in which its dissolving ability and chemical activity of the dissolved substances are abnormally increased. In this state, water is able to more easily hydrate hydrophilic substances mixed with it, and the substances dissolved and dissolved in it dissociate better into ions and enter into chemical reactions with each other. As a result of such processes, the nonequilibrium state acquired during processing is relaxed and a new thermodynamic equilibrium is established. Even if the solution after sonochemical treatment is not mixed with anything, the equilibrium in it still occurs again due to the restoration of the destroyed molecular associates of water and hydrated shells of ions and molecules, electrolytes and colloids dissolved in it, accompanied by the release of previously obtained energy in the form of heat, since hydration is an exothermic reaction [3, 4]. The sonochemical treatment sometimes also includes the dispersion of phases of aqueous emulsions and suspensions due to cavitation erosion and segregation [5], as well as the destruction by pressure pulses of the shells of microbial bodies - mechanical bacteriolysis (RU 2366347, 2009, RU 2356845 2009), which occur in conjunction with the above processes.

The invention can be applied to a non-reagent decrease in the temporary hardness of water by a suprathermal change in the reverse solubility of carbonic hardness salts due to the destruction of the hydrated shells of bicarbonates and thereby stimulation of the reaction resulting in the formation and precipitation of insoluble carbonates, as well as for sterilization of water and aqueous solutions. These processes can be used in water treatment for domestic and household needs, in medicine and pharmacology, as well as in the food and processing industry for the treatment of water and solutions intended to become components of drugs, food products, processed foods and raw materials. Further, the term “solution” will be applied to aqueous solutions, including, but not limited to, solutions with zero solute content.

A number of methods and devices that implement these methods are known - cavitation reactors for processing solutions in the field of application described above (RU 2226428, 2004; RU 2228217, 2004; RU 2246347, 2005; RU 2252070, 2005; RU 2254913, 2005). The technical result of their use is to ensure uniformity of the effect of cavitation energy on the solution in the cross section of its flow or in the volume of the reactor and, in some cases, to minimize the erosive effect of cavitation on the structural elements of the reactor, and energy means the potential component of cavitation energy, since it is the reason cavitation erosion [5]. Moreover, since the process of the effect of cavitation on the treated solution is temporary, and on the structural elements of the reactor constant, then the energy in relation to which optimization is carried out is understood as the energy released over a certain short period of time - the period of elastic oscillations generating cavitation. The uniformity of treatment is achieved by choosing the dimensions of the cavitation reactor, which affect the spatial distribution of the relative bulk density of this energy or the erosion coefficient [5], which is also a relative value. The performance of the process or the processing time of a specific amount of solution, by which it is possible to estimate the amount of energy expended per unit volume of the solution, is not regulated. That is, these analogs dictate the requirements in fact with respect to not power, but power, and for their use in a particular technological process, it is necessary to establish in some way how long this power must affect one or another volume of the solution in order to obtain the desired result. Moreover, the absolute value of the energy density released during the period of generation of cavitation ultrasound in these analogues is most often not specified, and calculations are carried out relative to the dispersion of its spatial distribution.

This prevents the achievement of the technical result of the invention formulated below when using the considered analogues, since to obtain it in each particular case, additional steps will be required to establish the performance of the process.

Known methods of cavitation treatment of solutions (RU 2240984, 2004; RU 2245624, 2005; RU 2254911, 2005; RU 2333156, 2008; RU 2366347, 2009), in which the value of the exposure power is given by the ratio of the amplitude of the sound pressure to the hydrostatic pressure in the solution. Sometimes this is done through the intensity of ultrasound - a value proportional to the square root of the amplitude of sound pressure, and sometimes through criteria that, in addition to it, include the acoustic characteristics of the processed solutions (RU 2308319, 2007; RU 2331478, 2008). In the latter cases, the invariance of the methods with respect to the concentration of the processed solutions is ensured. Although these methods are aimed at expanding the range of physical properties of the processed solutions and increasing the efficiency of acoustic power, they again do not contain signs that determine the amount of energy required to perform a specific processing task, and therefore do not allow to obtain a technical result of the invention.

The closest technical solutions known to the applicant in the field of the subject of the invention are the method chosen by its prototype, which processes water intended for hydration of biopolymers in the processing of agricultural and natural raw materials for medicinal, food and technical purposes (RU 2279918, 2006). It is known that in chemically pure water a higher intensity of elastic vibrations is required to obtain cavitation power the same as in a solution with a density greater than that of water [6], therefore, as described in the description of the prototype, it can be used in the processing of such aqueous solutions . That is, the scope of the invention and its prototype are completely the same.

Processing when using the prototype is carried out with a given amplitude of sound pressure, causing cavitation of the acoustic wave, and with a given performance depending on the volume of the cavitation reactor. The recommended sign of the prototype, the amplitude of the sound pressure is 5.5 hydrostatic pressure values in the solution, and the process productivity should be no more than 450 expressed in cubic meters of reactor volumes in which they are being processed per hour. Since the square of the amplitude of the sound pressure is proportional to the acoustic power divided by the area of sound emission, in the prototype the amount of energy that needs to be spent on processing a certain volume of the solution can be considered indirectly given. Using the well-known correlations of the theory of elastic vibrations and the theory of acoustic cavitation [6, 7], it can be calculated that in the volume of the reactor, which occupies the entire cavitation region, the specific energy consumption of the prototype at an average productivity will be about tens of kilowatt hours per cubic meter of the treated solution. And, for example, to heat a cubic meter of water to pasteurization temperature under adiabatic conditions, hundreds of kilowatt hours will be required. This is the advantage of the epithermal method of energy transfer during cavitation treatment, to the field of which the prototype of the invention relates. However, the prototype has disadvantages that do not allow using it to obtain the technical result of the invention.

The first of these, which is especially significant in the field of application of the invention, where the solutions become part of drugs or food products. As is known, the formation of hydroxyl ions and radicals takes place inside cavitation bubbles in water, albeit in small quantities, as well as the synthesis of Н ₂ О ₂ due to dissolved oxygen of the air and pyrolysis products of the vapor-gas mixture, which is heated inside the bubbles at the stages of their compression to high temperatures [6, 8]. Hydrogen peroxide, the formation of which is directly stated in the description of the prototype, by itself, either in a mixture with peroxidase-type enzymes present in the biomass, or in a mixture with iron ions in water, called Fenton’s reagent, is a strong oxidizing agent [9]. Due to its oxidizing effect, it, despite its useful ability to suppress the activity of anaerobic microbes, nevertheless, for example, does not contribute to the preservation of biomass mixed with a solution that contains lipids, and can also reduce the operational life of equipment with which the solution has contact. In this case, the solution itself may be contaminated with metal oxidation products.

The second drawback is associated with the well-known fact that cavitation regions are formed in those parts of the space of a standing elastic wave, where the so-called cavitation threshold is overcome by sound pressure, which depends on hydrostatic pressure and temperature [5, 6], and part of it is lost on each such region energy turning into cavitation energy [10, 11]. The power of an elastic standing wave in water even at very high intensities of its radiation is exhausted and is not able to cause cavitation already at a distance of three to four half-waves from the emitter [12]. In addition, the surface of the surface emitting ultrasound can be not only equal (RU 2254913, 2004; RU 2246347, 2005), but also a smaller cross-sectional area of the reactor [US 3519251, 1970; 12]. Therefore, the assessment of the energy impact of cavitation through the entire volume of the reactor is too generalized and correct only for reactors where cavitation can be considered valid in the entire volume. In opposite cases, this can lead to insufficient processing, or vice versa to excessive expenditure of energy if the solution is processed with an acoustic resistance higher than that of water.

The invention consists in the following. It became known that only cavitation formed at amplitudes of the sound pressure that causes it, not exceeding a certain threshold value, does not lead to the formation of peroxide compounds in quantities that can be determined by official methods for monitoring their maximum permissible concentrations [14]. The dissolving ability of the water treated in this mode, however, is significantly increased, which is reflected in protocol No. 009 of 02/10/2009 of tests carried out in a testing laboratory accredited by the ROSS RU.0001.515746 certificate. From the standpoint of physical chemistry and acoustics, this fact is explained by the fact that, at low amplitudes of sound pressure, the repetition rate of cavitation pressure pulses is greater than at high ones, and the absolute values of achieved pressures in cavitation bubbles are less [5, 6, 10]. It follows that the thermodynamic conditions inside the bubbles at small amplitudes of sound pressure, if they lead to the synthesis and diffusion of H ₂ O ₂ into water [8, 9], are only in small quantities. But the pressure impulses produced by the bubbles destroy the associative structure of water as well as at higher amplitudes. Indeed, although these pulses become smaller in absolute magnitude of pressure, they themselves become larger per unit time, that is, the work on the destruction of hydrogen bonds, which are usually characterized by energy [1-3], remains in a large range almost unchanged. Therefore, when determining the energy of cavitation disintegration, one should proceed from the intensity of ultrasound corresponding to the amplitude of sound pressure in the treated solution as low as possible than that of the prototype, and at the same time take into account the volume actually occupied in the reactor by cavitation areas. In addition, it is known and patented (RU 2366347, 2009) that the fact that taking into account the temperature-dependent parameters of the state of water vapor in cavitation bubbles when determining the level of acoustic power in processes where the sonochemical epithermal effect is combined with thermal influences, avoids unnecessary energy costs. However, the indicated analogue takes into account the temperature range up to the boiling point. Hydrogen bonds in water, which form its associative structure, can be destroyed by the kinetic energy of molecules, acquired by heating to temperatures below the boiling point - approximately + 60 ° С. Therefore, it makes no sense to take into account higher levels of thermal energy introduced into the process of disintegration, since the cavitation effect in this case becomes generally unnecessary.

Thus, in order to preserve the effects of disintegration, minimize the formation of peroxide compounds and prevent unnecessary energy consumption during sonochemical treatment of solutions, it is necessary to find the dependence of the specific energy consumption of the disintegration process on all of the above factors. By setting up computational and field experiments, particular empirical dependencies were found, which were then generalized and approximated by an analytical function of the solution temperature t and the relative amplitude of the sound pressure in it a, which is equal to the ratio of the absolute amplitude to the hydrostatic pressure in the treated solution, of the form:

determining the specific productivity of the cavitation disintegration process in the water contained in the solution. Formulated by function (1), the specific productivity p is only a necessary condition for obtaining the technical result of the invention and determines the maximum amount of water contained in the volume of solution in cubic meters, the processing of which requires one megajoule of acoustic energy. It approximates the obtained empirical dependences with an amplitude of sound pressure exceeding the hydrostatic pressure in the solution, but less than that of the prototype, that is, in relative units at 1 <a <5.5 and at a solution temperature t in degrees Celsius not higher than + 60 °. These limitations constitute a sufficient condition for obtaining the technical result of the invention.

The technical result of the invention is to reduce the energy intensity of the process of sonochemical treatment of aqueous solutions, as well as the content of chemical compounds which are oxidizing agents formed in them under the influence of cavitation while maintaining the dissolving ability of water resulting from processing.

кубических метров воды, затрачивают не менее одного мегаджоуля энергии ультразвука, изучаемого с амплитудой давления, отношение которой к гидростатическому давлению в реакторе принимают в диапазоне 1<а<5,5.The specified technical result is achieved by the fact that in the known method for sonochemical treatment of aqueous solutions intended for hydration of biopolymers in a cavitation reactor with a given pressure amplitude of ultrasound emitted into the reactor and with a given productivity, the difference is that at a temperature t of not higher than +60 degrees Celsius for processing volume containing

cubic meters of water, spend at least one megajoule of ultrasound energy, studied with a pressure amplitude, the ratio of which to the hydrostatic pressure in the reactor is taken in the range of 1 <a <5.5.

Figure 1 shows a nomogram graphically illustrating the function (1). On the curves showing the dependence of the specific productivity p during the disintegration of chemically pure water in m ³ / MJ on the sound pressure amplitude a in relative units for the fixed values of the water temperature numerically indicated on these curves.

Figure 2 shows a sketch of a snap for comparative studies of the materiality of the features of the invention. Designated: 1 - capacity for collecting electrolyte solution; 2 - a glass with a fitting for fixing on the path of the flow of treated water laboratory sieve 3 with tablets of dissolved electrolyte 4; 5 - fitting for connection with the outlet pipe of the reactor.

Figure 3 shows a photograph of the appearance of samples of pelletized NaCl after staying in settled tap water with room temperature (left) and sonochemically treated water.

It was established by experimental studies that when the chamber volume of the cavitation reactor is 0.352 dm ³ and the mechanical power of the ultrasonic emitter with which it is equipped with 360 W, the optimal performance when processing a saturated solution of sodium chloride is 60 dm ³ / h [11]. This corresponds to the productivity calculated from expression (1) at a hydrostatic pressure equal to atmospheric, sound pressure amplitude 195 KPa and room temperature of the process. According to the prototype, such a reactor is able to process a solution of about 450 · 0.352 · 10 ^-3 · 10 ³ = 158 dm ³ / h, that is, 2.6 times more, but this will require almost 5.5 ² : 1.95 ² = 8 times greater acoustic power. In other words, when using it to implement a prototype, it would take 65 MJ of acoustic energy to process a cubic meter of solution. The implementation of the claimed method at the same reactor when processing the same saturated solution, in the volume of which at this temperature may contain 86% water [15], at atmospheric pressure and with an amplitude of sound pressure of 195 KPa, requires at least almost three times less energy - only 22 MJ. But in order to realize the specific energy consumption of 65 MJ / m ³ under the same conditions, according to (1), the sound pressure amplitude will be only about 148 KPa, and not 550 KPa, as in the prototype. With such an amplitude, unlike the prototype of peroxide compounds in a solution should not form at all [14].

Thus, a comparison of the closest analogue characterizing the prior art in the field of the subject invention with the proposed method shows the advantages of the latter in energy intensity and safety associated with the formation of oxidizing compounds.

The significance of the necessary and sufficient conditions dictated by the features of the invention to achieve its technical result and their influence on the absolute value of this result in terms of the dissolving ability of water was experimentally tested on the same cavitation reactor. The dissolution rate of dry electrolyte in water corresponding to SanPiN 2.1.4.1074-01 was measured. Tableted sodium chloride was taken as the electrolyte according to TU2152-001-84091640-2008, which has a uniform dissolution of the tablets - the thawing effect, and we used equipment to check the operability and functioning of the RKU type reactors according to TU5130-002-26784341-2008, shown in Fig.2. The dissolution rate was measured by the weight loss of five tablets of electrolyte 4, which were evenly placed on a grid of laboratory sieve 3 according to GOST R 51568-99, tightly inserted by the lower edge of the shell into a metal cup 2 with a fitting, placed in a container 1. Water was pumped from the reactor through the master the feed rate of the throttle through a tube connected to the nozzle 5, into the tank 1 through a sieve 3 with the electrolyte tablets 4 in it.

, где: М - суммарная исходная масса пяти таблеток, смоченных в течение короткого времени в воде; m - суммарная масса таблеток после частичного растворения в течение 0,2 часа, измеряемых с момента начала поступления воды через сетку сита.The weight loss of the tablets upon dissolution was measured by weighing on a laboratory balance and expressed as a percentage as:

where: M is the total initial mass of five tablets soaked for a short time in water; m is the total mass of tablets after partial dissolution within 0.2 hours, measured from the moment water begins to flow through a sieve.

The control series of experiments was carried out with the ultrasound source turned off, the first at room temperature, and the second at + 60 ° C. The experimental series were delivered in three, 5 experiments each: the first two also at room temperature, the third - at + 60 ° C. The first series with an acoustic power of 360 W and a productivity of 51 dm ³ / h fully corresponded to the claimed method, since the necessary and sufficient conditions were fulfilled (which, according to [14], also prevented the formation of peroxide compounds). The second series, with an acoustic power of 250 W and the same as in the first performance, corresponded to the claimed method only for fulfilling sufficient conditions, but ignored the necessary condition, since in accordance with (1) with such acoustic power, the productivity should be about 18 dm ³ / h . And the third series, with the same acoustic power and performance as in the first, corresponded to the claimed method for fulfilling only the necessary condition, since, in accordance with the distinguishing feature, the temperature of the solution cannot be equal to + 60 ° C, and performance when the temperature approaches + 60 ° C tends to infinity (Figure 1).

The numerical data obtained as a result with confidence intervals of errors at a 95% ^significance level are summarized in a table.

AN OBJECT Identification Unit. THE CONTROL EXPERIENCE PARAMETER one 2 one 2 3 Specific Energy Costs p ^-1

- ~ 160 * 25 16 ~ 185 * Relative amplitude of sound pressure but units - - 1.95 1,63 1,63 Mass loss δM % 9 ± 0.4 15 ± 1,0 15 ± 0.7 13 ± 0.6 16 ± 1,2 * equivalent, calculated by the specific heat of water [15].

It can be seen that the prototypes of the first series, which were processed to fulfill all conditions dictated by the features of the invention, and the control samples of the second series, which were simply dissolved in water heated to the temperature of destruction of molecular associates, lost almost the same mass. However, the energy spent in the experiments was significantly less without using thermal energy at all. In general, without energy consumption, the rate of dissolution of the electrolyte, which characterizes the level of energy exposure, is much lower (control 1). This suggests that the use of all the features of the invention provides a technical result in full. In the second series of experiments, where the specific energy expended was almost 1.6 times less than the required condition for achieving the technical result of the invention, the dissolution rate was also lower than in the first, and the technical result was not achieved. And finally, in the third series of experiments, in which one of the features of the invention, which is a sufficient condition for obtaining a technical result, was not fulfilled, excessive energy was spent, even in excess of that spent in the second control series. At the same time, the dissolution rate practically did not increase. Therefore, it makes no sense to spend ultrasonic energy if the process is at a temperature of + 60 ° C and above.

Thus, the analysis of the features of the invention in its practical implementation shows their materiality in relation to the specified technical result. The applicant has not yet identified any known solutions regarding similar requirements for specific productivity and process parameters of sonochemical treatment of aqueous solutions for hydration of biopolymers.

The proposed method on an industrial scale can be carried out as follows. Suppose, for example, it is necessary to process water in order to soften it and improve the solubility of biopolymers of skimmed milk powder in it during the production of milk drinks [16, 17]. In [14], it is said that in terms of specific productivity and acoustic parameters, industrial ultrasonic processors manufactured by Hielscher Systems GmbH (Germany) are comparable with reactors of the ECU type. Such processors of the UIP 10000 type assembled in one unit with a mechanical power of 9 kW each (90% efficiency) without any technical modifications at the room temperature of the treated water will provide, when all the features of the invention are realized, the required water treatment with a capacity of 5.5 m ³ / h. On the website of the company Hielscher Systems GmbH [18] among the UIP apparatus applications indicated there are tables of the capacities provided by them for:

- esterification of biodiesel raw materials;

- preparation of oil-water emulsions;

- extraction of substances from plant materials;

- dispersion and deagglomeration of solid phases of suspensions;

- wet grinding and grinding.

But their application according to the purpose given in the considered example of industrial implementation of the invention is not provided for and the performance in such application is not regulated. The above information indicates the possibility of implementing the claimed invention using the methods described in the application or known methods and methods, as well as the possibility of achieving with it the above technical result.

LITERATURE

1. Rogov I.A., Shestakov S.D. Epithermal change in the thermodynamic equilibrium of water and aqueous solutions: Misconceptions and reality // Storage and processing of agricultural raw materials, 2004, No. 4, No. 10.

2. Alikberova L.Yu., Savinkina E.V. and Davydova M.N. Fundamentals of the structure of matter. - M.: MITHT, 2004.

3. Pimentel J., McClellan O. Hydrogen bond. - M .: IIL. - 1964.

4. Shestakov S.D., Kasulya O.N., Befus A.P. Features sonochemical studies in the food industry. - 2008. - Dep. in VINITI, No. 886-V2008.

5. Shestakov S. D. Fundamentals of cavitation disintegration technology. - M .: EVA-press, 2001.

6. Knepp R., Daily J., Hammit F. Cavitation. - M .: Mir, 1974.

7. Gorelik G.S. Oscillations and waves. - M .: IF-ML. - 1959.

8. Elpiner I.E. Ultrasound. Physico-chemical and biological effects. - M .: IF-ML, 1963.

9. Shamb U., Setterfield C. and Wentworth R. Hydrogen peroxide. - M .: IIL, 1958.

10. Physics and technology of powerful ultrasound. Powerful ultrasonic fields // ed. L.D. Rosenberg. - M .: Nauka, 1968.

11. Shestakov S.D., Befus A.P. Formulation of the similarity criterion for sonochemical reactors when processing media that do not provide acoustic resonance, 2008. - Dep. in VINITI, No. 840-V2008.

12. Shestakov S.D., Kasulya O.N., Befus A.P. Features sonochemical studies in the food industry. - Vologda, 2008 .-- 14 p. - Dep. at VINITI RAS, No. 886-V2008.

13. Shestakov S.D. On the distribution of the potential energy density of multi-bubble cavitation relative to the harmonic wave generating it // Transactions of the 16th Session of the Russian Acoustic Society. - M .: GEOS, Volume 1, 2005.

14. Krasulya O.N., Shestakov S.D., Bogush V.I., Artemova Y.A., Kosarev A.E., Ivanov A.A., Befus A.P., Gorodishchensky P.A. Processes and apparatuses of food sonotechnology for the meat industry // Meat industry, No. 7, 2009.

15. A quick reference to chemistry / ed. O.D. Kurylenko. - Kiev: Naukova Dumka, 1974.

16. Shestakov S.D. Technologies of cavitation disintegration in dairy production // Dairy industry, No. 9, 2007.

17. Galstyan A.G., Petrov A.N., Chistovalov N.S. Advanced water treatment technologies in the production of reconstituted dairy products // Storage and processing of agricultural raw materials, No. 11, 2007.

18. http://www.hielscher.com.

Claims (1)

A method for sonochemical processing of aqueous solutions intended for hydration of biopolymers of aqueous solutions in a cavitation reactor with a given pressure amplitude of ultrasound emitted into the reactor and with a given capacity, characterized in that at a temperature t of not higher than + 60 ° C for processing a volume containing

m ^{3 of} water, spend at least 1 MJ of ultrasound energy emitted with a pressure amplitude, the ratio of which to the hydrostatic pressure in the reactor is taken in the range of 1 <a <5.5.

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