Vol 52, No 1 (2018)

Transformation of the velocity and concentration profiles in a diffusion boundary layer in the presence of a transverse mass flow through the interface complicates the use of widely known phenomenological relationships in the description of diffusion mass flows. Taking this into consideration, a new formulation of the mass-transfer equation has been proposed that adequately describes the mass transfer in binary and multicomponent mixtures. It has been shown that the new structure of the mass-transfer equation is in good agreement with the experimental data for a large variety of separation processes in the gas (vapor)–liquid systems (evaporation, condensation, distillation, etc.), as well as with the similarity criteria specially introduced for taking into consideration transverse mass flows. The versatility and adequacy of the proposed configuration of the mass-transfer equation has been proved.

The chemical technology processes that are of practical importance in the chemical technology system for thermal treatment of raw materials such as drying, coke combustion, decarbonization of phosphorites, melting of batch particles, formation of agglomerated cake, and moisture vapor condensation in lower beds were studied. These processes are thermally activated and proceed during agglomeration in the phosphate raw material. The results of the experimental studies of the sintering kinetics of the phosphate raw materials were presented. A multifactor dependence was revealed in the agglomeration processes under study. Increased resistance to the movement of the heat carrier gas was observed in the melting and fit agglomerate zones, which led to a decrease in the rate of filtration of the heat carrier gas through the bed and worsened the conditions of the chemical technology processes.

The problem on the kinetics of extraction of the target component (technological contaminant) from plate-shaped bodies in an apparatus for a semi-continuous (periodic for the solid and continuous for the liquid phase) process in which the liquid phase is completely mixed was formulated and solved analytically. The process kinetics was analyzed by the numerical method at different specific consumptions of the liquid phase. Recommendations were given on the use of the solution for calculating the kinetics of extraction of technological contaminants from textile materials during washing in the chemical finishing technology.

The estimation of the dilution rate in a fermenter is associated with biotechnological features. The time of residence of the stream of substrates in the fermenter should ensure the growth of the microbial population. In other words, if the dilution rate D is higher or equal to the limiting value D_lim, synthesis has no time to take place and, as a consequence, no product (specifically lactic acid) is formed. In this study, as a result of mathematical modeling, the technological parameter D< D_lim has been calculated, which ensures real conditions for the practical implementation of the continuous process of lactic acid production.

The influence of the specific surface area of air bubbles in the process of bubbling on the oxidation rate of Fe²⁺ ions of model solutions prepared using distilled water with the addition of Fe²⁺ ions in the form of iron(II) sulfate (pure grade). The dependences of the rate of Fe²⁺ oxidation in water during air bubbling have been found.

The problem of calculating and optimizing the functioning of various schemes of connections of electrochemical reactors has been considered with flow-through 3D electrodes from carbon fibrous materials with circulation and direct and combined feeding of the treated solution during the electrodeposition of metals from multicomponent electrolytes taking into account the change in the initial parameters of the electrode, electrode reactions, and conditions during electrolysis.

Methods of estimating the vibrational effect of high-pressure pulses on the confuser of the complex technological pipeline have been presented. Hydrodynamic calculations are performed using the Ansys Fluent software package. To analyze the propagation of high-pressure pulses, time series of hydrodynamic variables have been constructed at several points of the model confuser located on the axis of the pipeline. Two linear stationary hydrodynamic models of the confuser have been constructed, and the possibility of their use in modeling the nonstationary propagation processes of high-pressure pulses has been studied. It has been established that, with an accuracy of more than 90%, the studied unsteady hydrodynamic processes in the confuser can be described by linear stationary models. An analysis of the amplitude–frequency characteristics of the confuser using these models showed that an approximately 100-bar impact on the confuser of pressure pulses is permissible and leads to pulsations of pressure with a signal-to-noise ratio of 110 dB, which does not exceed the maximum permissible level of pressure pulsations.

The hydrodynamics and the flow field in an agitated vessel were measured using 2-D time resolved particle image velocimetry (2-D TR PIV). The experiments were carried out in fully baffled cylindrical flat bottom vessels 300 and 400 mm in inner diameter. The 300 mm inner diameter tank was agitated by a Rushton turbine 100 mm in diameter, and the 400 mm inner diameter tank was agitated by a Rushton turbine 133 mm in diameter. Three liquids of different viscosities were used as the agitated liquid: (i) distilled water (ν = 9.35 × 10^–7 m²/s), (ii) a 28 vol % aqueous solution of glycol (ν = 2 × 10^–6 m²/s), and (iii) a 43 vol % aqueous solution of glycol (ν = 3 × 10^–6 m²/s). The velocity fields were measured at an impeller rotation speed in the range from 300 to 850 rpm, which covers the Reynolds number range from 50000 to 189000. This means that fullydeveloped turbulent flow was reached. The experiments were performed to investigate the applicability of the following relations: ε* = ε/(u⁴/ν) = const, vK/u = const, Λ/ηK = const, τ_Λ/τ_K = const, ε* = ε/((Nd)4/ν) = const, Λ/d ∝ Re^–1, ηK/d ∝ Re^–1, vK/(Nd) = const, Nτ_Λ ∝ R^–1, Nτ_K ∝ Re^–1, and ε/(Nq) ∝ Re. These formulas were theoretically derived in our previous work, using turbulence theory, in particular, using turbulence spectrum analysis. The correctness of the proposed relations is investigated by statistical hypothesis testing.

Development of ionic liquid-based aqueous two-phase systems as a new viewpoint in the expansion of research in the field of biological materials separation depends on accurate determination of phase diagram. In this work, the efficiency of artificial neural network was studied aiming to forecast the formation possibility of phase diagrams of aqueous two-phases systems for the ability of range of ionic liquids composed of different anions with a selected salt. In order to investigate effects of the anion of ionic liquids on phase diagram, this study was performed on 472 of experimental data. On the basis of the accurate set of statistical measurements obtained, a good agreement between the experimental data points and the predicted values was gained. Furthermore, the group method of data handling was applied to model the molality of ionic liquids and a reasonable agreement was obtained between experimental data and the predicted values of this model.