Vol 57, No 5 (2023)

The process of perfluoro(7-methylbicyclo[4.3.0]nonane) (MBCN) purification from an industrial mixture of decalin or naphthalene fluorination products is considered. According to experimental data, distillation separation allows us to concentrate MBCN to a fraction with the target-component content of more than 0.950 wt. fr., after which the process efficiency begins to decrease quickly; upon reaching a concentration of 0.975 wt. fr., separation practically breaks down (the value of the separation coefficient Ksep → 1). The process of purification of MBCN by the method of heteroazeotropic distillation using acetone (Aс) as a separating agent is proposed, the process being realized on a batch semi-industrial distillation column. The method makes it possible to intensify significantly the final stage of purification and to increase the MBCN content from 0.950 to more than 0.998 wt. fr., the mass fraction of the enriched fraction sampling comprises more than 0.85 of the load and the product yield being above 88%. The values of the separation coefficients between the distillate and the bottom product and the coefficients of enrichment for the target and impurity components are given; for the MBСN–Aс binary system, data on the liquid–liquid phase equilibrium and heteroazeotrope characteristics are determined.

Каскад смесительно-отстойных экстракторов может работать как в режиме противоточной экстракции, так и в режиме хроматографии. При работе в режиме хроматографии органическая фаза не выводится из экстракторов, а циркулирует между смесительной и отстойной зонами в каждом аппарате. Настоящая работа посвящена теоретическому анализу процессов разделения в каскаде смесительно-отстойных экстракторов при работе каскада в режиме жидкость-жидкостной хроматографии и противоточной жидкостной экстракции. Рассмотрены обычные технологические схемы процессов хроматографического разделения и схемы с рециклом водной фазы. Показана перспективность применения в экстракционных технологиях принципов хроматографии для получения чистых и сверхчистых продуктов в промышленном масштабе.

An analytical model of a solid–liquid heterogeneous reaction to form a gas phase was presented. The model is based on the analysis of the main parameters that have the most significant effect on the intensity of the reaction. The formation of gas–liquid dissipative structures in the form of alternating flows of reacting phases that perform relaxation pulsations was shown. The formation, detachment, and movement of bubbles were described with a satisfactory adequacy. The dynamics and conditions for the formation of a gas bubble on a solid reaction surface were characterized. Relationships were obtained for estimating the mass-transfer coefficients, which correlate with experimental data. The developed analytical model of the heterogeneous reaction will give a better insight into the essence of the melting processes in ore-thermal furnaces, which will make it possible to make changes to these processes using qualitatively new parameters of their characteristic reactions. Analysis of the hydrodynamics with the formation of the gas phase by analytical and numerical methods suggested the type of the flow of the liquid phase. Typical was the presence of hydrodynamic structures that determined the ordered movement of the liquid phase with various methods of supplying the gas phase. The values of critical mass-transfer parameters were determined. In contrast to the boiling process, a crisis of the heterogeneous reaction is impossible because of the shielding of the reaction surface.

The article presents a compact and exhaustive interpretation of the foundations of energodynamics and shows that it significantly extends the horizons of natural science and opens new avenues to improve the scientific bases of chemical technology.

Thermal engineering experiments were carried out with laboratory water-to-water tube-in-tube heat exchangers of the same design parameters with smooth and profiled inner tubes. The tubes were profiled by confuser–diffuser constrictions of the flow section of the inner channel, which were formed by the deformation of their walls and placed along the length at a step that was constant and equal for all profiled tubes. The obtained results showed a dependence of the heat transfer enhancement in the tube channel on the Reynolds and Prandtl numbers, with the dependence on the latter being much stronger than that on the former, at least in cases where the heat carrier is water.

In some cases, a reaction in the oscillatory mode has a higher selectivity for the target product. To organize production in this mode, it is necessary to determine the conditions under which fluctuations occur, as well as to consider the very nature of the fluctuations. In this work, a parametric analysis of the basic kinetic model of an oscillatory reaction without autocatalysis was made. The boundaries of the parameters at which the system oscillates were found. Phase portraits of the system and bifurcation curves were constructed. Stationary states of the system were analyzed. The type and number of stationary states were identified. It was shown that the system at certain parameters has three stationary states: two unstable nodes and a saddle. Parametric analysis of basic models will allow selecting initial approximations for calculations of more complex models of real reactions.

The article presents new details of an algorithm and compares the results of calculating the heat and mass transfer of water and air in spray apparatus for the regimes of cocurrent and countercurrent of phases, taking into account the early crisis of drops drag and the accompanying crisis of heat and mass transfer. The mathematical model used is based on nonstationary differential equations for the flow of a compressible medium, supplemented with the equations of heat and mass transfer from drops to the gas. The known explicit Lax–Wendroff scheme is used in difference analogs of the equations of continuity and phases flow. The distributions of phases velocities and temperatures, and densities of water vapor in air and saturated vapor near the surface of drops in the two-phase flow are calculated to compare the co- and countercurrent flows of phases through the cylindrical apparatus. In particular, the calculations determined the dependences of the average temperatures of the gas and the liquid over the outlet section of the apparatus for each phase on the gas flow through it