Vol 51, No 3 (2017)

New data on the concentration profiles in a packed column during extractive distillation of benzene–heptane mixture in the presence of N-methylpyrrolidone as a separating agent have been obtained. A calculation method for the process based on partial mass transfer coefficients in the vapor and liquid has been proposed. The calculated and experimental data have been compared. It has been shown that both continuous and batch extractive distillation are calculated more precisely using the proposed model compared to the equilibrium model.

Experimental investigations of velocity fields have been carried out in static mixers filled by Inzhekhim random packings of various sizes and Rashig rings. Studies have been performed on a laboratory setup by stereoscopic particle image velocimetry using a Polis multiphase flow measurement system. Experimental data have been supplemented by the results of numerical modelling of the hydrodynamics of flow, which were obtained using ANSYS Fluent software.

The results of analyzing mathematical models of the process of batch fermentation for the production of lactic acid have been presented. Three groups of mathematical models have been considered. The first two groups are based exclusively on the notion of the specific growth rate, dependent or independent on substrate concentration. The third group uses the notions of the specific rate of substrate consumption and specific rate of product formation in additions to the notion of specific growth rate. The numeric estimates of constants are presented for the majority of models as well as comparison with the experimental studies. Mathematical models of the processes where the formation of side products is possible have been discussed, which may or may not be of value on their own. The possible practical applicability of the models has been evaluated based on the results of the analysis.

In this paper, the thermal characteristics of phosphate raw materials have been studied, including thermal conductivity and volumetric heat capacity in the temperature range that has practical significance in the chemical and technological system of thermal preparation of raw materials. The method of the regular regime of the third kind and the method for solving the inverse heat-conduction problem have been used based on the joint solution of the equations of heat transfer and the kinetics of chemical reactions taking into account the most important accompanying phenomena. A dilatometric analysis of the studied samples of phosphate raw material has been presented.

In this paper, we consider the mass-transfer process in apparatuses with a fixed granular bed. The literature data were analyzed and it was shown that the main driving force of the mass transfer between the outer surface of the grains and the gas flow at a significant difference between the temperature of the phases is the difference of the reactants partial pressures. A comparison of the results of calculating the mass-transfer coefficient using the most popular in the domestic and foreign literature empirical correlations of Sherwood number on the Reynolds and Schmidt (diffusion Prandtl number) numbers was performed. It has been shown that the calculation results do not differ from each other despite the difference in the calculation formulas. The methodology of calculating the mass-transfer process in the two-phase model of a fixed catalyst bed has been provided.

A mathematical model has been developed for the deformation of a polymer nanocomposite containing hard and soft inclusions. For the model to be designed, an algorithm for generating the structure based on the cellular automaton has been used. The polymer structures with different filler content have been obtained and numerical modeling of the strain-strength properties have been carried out. The optimal composition of the polymer nanocomposite has been determined. An example of parallel computing for implementing the calculation tasks has been given. The content of the hard filler has been found to be in the range 50–80% and the soft one was in the range of 0–12%. Micro- and macroparameters of the polymer nanocomposite have been determined. The best nanocomposite have been found to contain 77% of the hard inclusions, 6–10% of the soft inclusions (polymer modifier), and 13–17% of the polymer matrix. The calculation results have been compared with the experimental data.

Thermodynamic, thermal, and ecological features of high-temperature steam–air reagents in plasma processing of waste have been considered. The possibility of the formation of extra-equilibrium concentrations of nitrogen oxides when using these reagents has been shown. Derived from the study of equilibrium compositions, approximation dependences of the bulk temperature of various steam–air mixtures on necessary specific energy consumptions on their heating at various mass concentrations of water vapor and various temperatures of the steam supplied to the reactor have been suggested.

Using high-speed video cameras (up to 10⁵ frames per second), a cross-correlation measuring system, and panoramic optical tracer visualization methods, some specific features have been revealed in the transformation of drops of liquids widely used in chemical technologies (kerosene, ethanol, water, acetone). The studies were performed for individual drops with characteristic sizes (radii) of 1–3 mm during their motion through a gas medium (air at a temperature of nearly 300 K) at velocities of 0.5–5 m/s. The ranges of change in the aerodynamic resistance coefficients c_d were determined for the studied liquid drops under the considered conditions. The effect of the sizes and velocities of drops on this parameter have been established. Real values of c_d for typical applications were shown to be much greater than for the corresponding droplike shapes.