卷 51, 编号 4 (2017)

Powder LSX zeolite samples of high phase purity and near 100% crystallinity have been synthesized in NaK, K, Na, and Li forms. The effect of the chemical nature and content of the exchange cation and air calcination temperature on the degree of crystallinity and the porous structure characteristics and adsorption properties of the mentioned LSX zeolite forms were established by X-ray diffraction and adsorption methods.

A combined granulation and encapsulation procedure in the production of sodium percarbonate (SPC) has been developed that enables the stabilization of SPC to form a coating on the surface of product granules in one technological stage. The separation of the granulating and encapsulating agents during the drying process and formation of an encapsulating coating are performed due to large differences in the solubility of the components of initial solution. Sodium polyphosphate or oxyethylidenediphosphonic acid used as encapsulating agents with an initial solution concentration (1%) in the combined granulation and encapsulation process enables the preparation of encapsulated SPC, which is significantly more resistant to wet carbon dioxide than unencapsulated product.

The processing of serpentinites by sintering them with caustic alkali has been shown. The majority of silica is leached from the resulting sinter and is recovered from the concentrate magnesium using solutions of strong mineral acids. Amorphous silica is leached from the residue with alkaline solution. The solutions and the solid residue are processed according to the existing technologies.

Some results of studying the compaction processes of multicomponent polydisperse materials (MPMs) with their preliminary surface treatment were presented. The efficiency of the use of mechanically activated MPMs in granulation processes compared with powder materials has been shown, and granule formation mechanisms have been established. Some process flowsheets have been developed for the production of granular materials by compaction.

The process of the atmospheric-oxygen-induced cracking of heavy oils of various nature and compositions in a continuous flow reactor has been studied. The process variables for conversion of heavy oils into gasoline and diesel fractions have been determined that ensure the maximum yield of the above fractions with simultaneous production of marketable heavy residues. The developed technology can be applied in industry upon minor upgrading of the operating thermal cracking or visbreaking units. This upgrade will result in a considerable increase in the oil refining depth.

The problems of utilizing diesel fuel produced from oil from Talakan oil field (Sakha Republic, Yakutia) have been considered. The analysis of applying depressor additives has been conducted with the objective of improving low-temperature properties of the produced fuel.

Published works conducted in Russia and other countries over the last 10–15 years regarding the application of solvent extraction in technological processes for recovering rare earth metals from various mineral and technogenic raw materials (bastnesite, monazite, loparite, xenotime, kularite, etc.) were analyzed in the present review. Raw materials containing rare earth are beneficiated by flotation, magnetic or gravity methods to produce rare earth concentrates, which are undergone hydrometallurgical processing. Rare earthcontaining concentrates or calcined residues are usually treated with inorganic acids. Then individual or mixed rare earths are extracted from pregnant leach solutions by solvent extraction. Various commercial extractants belonging to different classes are used for extraction. A large number of stages are usually required to separate rare earth metals.

Various aspects of the electroflotation technology for wastewater treatment and the extraction of valuable compounds from technological solutions have been reviewed. A brief description of the history of the appearance and improvement of the technologies based on the use of electroflotation process has been given. Their main operational parameters have been considered. Data on the mathematical simulation of the process have been provided. Achievements on the extraction of nonferrous and rare-earth metals from wastewaters, technological solutions, and technogenic waste have been discussed in detail. The results of investigations on the effect of various flocculants and surface-active compounds on the electroflotation process have been presented.

The management of the economy and the mathematical formulation of the problem of optimal dynamic (multiperiod) logistic planning of the initial and modified supply chain of a gas condensate stabilization plant has been suggested in the form of a multidimensional mixed-integer linear programming problem. An interactive procedure for solving this problem has been developed using the Oracle Strategic Network Optimization software suite. Optimal logistic planning parameters have been calculated for the new modified supply chain with the commissioning of a new plant for processing a wide fraction of light hydrocarbons.

The simulation of phase equilibrium in a multicomponent reaction system of ethanol dehydrogenation process has been performed. The structure of the distillation diagram of this system has been found and its evolution during changes in pressure has been studied. An analysis of the diagram properties has made it possible to define the range of values of the operating parameters that allow for the separation of the reaction mixture in order to propose a structure of technological separation system and to carry out its parametric optimization.

Unsteady axisymmetric boundary layer equations for power-law non-Newtonian fluids are analyzed. A number of new exact solutions containing arbitrary functions and free parameters are constructed using generalized or functional separation of variables. The solutions are obtained using a Crocco-type transformation reducing the order of the equations examined and simpler point transformations. Along with the exact solutions to axisymmetric boundary layer equations, some new exact solutions to planar boundary layer equations for non-Newtonian fluids are constructed. Several properties have been discovered that allow the exact solutions of the unsteady axisymmetric boundary layer equations to be generalized by including additional arbitrary functions therein. All results refer to an arbitrarily shaped streamlined solid of revolution.

Generally, diffusion through film thickness is used for correlating data in the industrial crystallization processes. Furthermore, mass transfer is an important phenomenon in most chemical processes and studies involving determination of mass transfer coefficients are necessary for a better estimation of equipment performance. Solid-liquid mass transfer coefficients in stirred systems have received substantial attention in the past due to their practical applications. In contrast, little information is available on solid-liquid mass transfer in crystallization systems, despite the importance of crystallization. In this work, an expression for the mass transfer coefficients in solution crystallization has been developed based on the Stefan problem formulation. The model is able to predict a finite mass transfer coefficient when the layer thickness vanishes. The obtained mass transfer coefficients agree with previously reported experimental data. Furthermore, it is found that the stagnant film for mass transfer has oscillatory behavior, and this behavior is a function of residence time.

The effect of typical admixtures (clay, sand, soil, and silt) on the integral evaporation characteristics of aqueous suspension drops in high-temperature gases (at nearly 1100 K) has been experimentally studied using optical methods and a high-speed video record system (up to 10⁵ fps). The heating and evaporation of suspension drops was established to appreciably intensify with a change in the relative mass fraction of admixtures within γ = 0–0.1 for sand and γ = 0–0.01 for clay, soil, and silt. An essential effect of the preliminary heating of suspensions on the intensity of their evaporation in a flow of high-temperature gases has also been revealed. Some recommendations have been formulated for selecting evaporation parameters for the studied suspensions in contemporary and advanced high-temperature chemical and thermal engineering technologies for the purification of water from admixtures and in the sphere of fire safety.

This work deals the computational performance improvement of vapor–liquid equilibria solver for fluids mixtures. The code here developed is based on the chemical potential equality (expressed in terms of fugacity) and implements Soave–Redlich–Kwong and Peng–Robinson equations of state with classical van der Waals mixing rules. To reduce the bulk of the computational effort required by the solver we propose the following approaches: (i) exploit high-order methods for the solution of Rachford–Rice equation; (ii) develop an efficient programming methodology for the sub-routines devoted to the fugacity coefficients computation in order to reduce their overall impact on the CPU-time exploiting the parallelism at CPU level, i.e. CPU pipelining, and cache blocking. In this paper we have carefully evaluated the effectiveness of the aforementioned approaches performing a suite of computations of the equilibrium properties of several literature mixtures. The pros and cons of the strategies here suggested are outlined and discussed.

A mathematical model of the preparation of aluminium hydroxide and Portland cement in tubular rotary kilns has been developed. Experimental data have been obtained by TG DSC on a NETCH calorimeter; mathematical models of reactors have been obtained based on an analysis of the motion of multiphase systems. The models of reactors have been used to solve the problems of optimizing the temperature profile in apparatuses using technological criteria of optimization by nonlinear programming methods.

A method for synthesizing nonspherical silver nanoparticles by reducing liquid extract of silver neodecanoate in benzyl alcohol has been developed. The method is simple and does not require the use of polyvinylpyrrolidone, sodium citrate or special methods using pre-synthesized seeds. The obtained particles have been investigated by the methods of electron microscopy, X-ray diffraction, and differential-thermogravimetric analysis. It has been found that triangular and hexagonal plates, as well as particles of pentagonal form and polyhedrons, are formed as a result of the reduction. The sizes of the obtained plates, depending on the synthesis conditions, vary from 80 nm to 2 μm. The method is promising for the industrial production of silver nano- and microplates.

The possibility of preparing ceramic-metal material based on titanium carbides and carbonitrides from the wastes of intermetallide alloys has been investigated. The effect of sintering conditions on the phase and structural formation of ceramic-metal material, as well as the composition and properties of the formed material, has been studied.

The chemical-technological features of using fluorine compounds in aluminum production have been studied. The modes and parameters of technological processes that significantly decrease the emissions of hazardous substances have been specified by the method of computer modeling. The methods for obtaining fluorides and optimizing their chemical and granulometric composition have been updated. The measures for improving the electrolysis technology that reduce losses of valuable components are developed.

Heat consumption in various two-column arrangements for separating ideal and real ternary mixtures by distillation have been compared. It has been shown that the first specified separation of ternary mixtures is not always the least energy-consuming process. The minimum heat consumption in different separation arrangements has been explained.

The review discusses common approaches to large-scale oil-spill management, one of the most serious ecological problems. New functional materials, such as biocomposite materials (BCMs), are a possible solution to the problem. The main principles of biocomposite development have been considered, as well as their properties and the possible application for aquatic remediation. The key advantages and value of BCM, their prospects for creating technologies that enable the cleanup of oil spills and wastewaters have been demonstrated.