卷 53, 编号 5 (2019)

A logical information algorithm has been proposed for choosing energy- and resource-efficient chemical technologies using the logical information modeling of business processes and intelligent models of knowledge representation for decision-making. Based on the structured analysis and design technique and intelligent models for representing knowledge about chemical technologies in the form of frames, a procedure has been proposed for constructing the logical information model of a business process for choosing an efficient technological solution. A logical information model for business processes and an algorithm for choosing an energy- and resource-efficient technology for processing associated petroleum gas have been developed.

Two methods to form the active surface of TsVM-type palladium-containing zeolite catalysts are studied. The substance of the active sites of these catalysts is palladium, which is introduced into TsVM-type zeolite by impregnation or ion exchange. Catalyst samples are tested in the n-pentane hydroisomerization reaction. A step mechanism of n-pentane hydroisomerization over palladium-containing zeolite is proposed, and its corresponding kinetic model is constructed. Kinetic experiments are carried out in a flow reactor with a 200-cm³ reaction zone. The pressure in the reactor varies from 10 to 30 atm, the temperature from 553 to 633 K, the hydrogen-to-(n-pentane + isopentane) molar ratio from 2 to 6, and the contact time from 0.05 to 2.0 h. The constants of the kinetic model, the variances of estimates of the constants, the variances of responses, the variances of observations, and the repeatability error variances are estimated by the maximum likelihood method from the results of the sequentially designed experiment. A precision kinetic model of n-pentane hydroisomerization over a TsVM-type palladium-containing zeolite catalyst has been built.

The butadiene and butane–butylene fraction are products of separation of the butylene–butadiene fraction (BBF) by chemisorption. Butadiene is a diene monomer for the production of elastomers and plastics. The butane–butylene fraction is used as a feedstock for various petrochemical processes, in particular, for the preparation of C₄ oligomeric products and methyl tert-butyl ether. A residual content of butadiene in the butane–butylene fraction of more than 0.5 wt % has a negative effect when it is used as a raw material for petrochemical processes; it also reduces the yield of butadiene. The article describes the method of purification of the butane–butylene fraction from butadiene by returning the part of butane–butylene fraction mixed with a stream of absorption ammonium–copper solution in the form of reflux in the chemisorption column. Mixing of flows is carried out in a tubular turbulent apparatus mounted in a reflux line. The organization of an additional contact of part of butane–butylene fraction with copper ammonia solution will increase the sorption efficiency of the column.

Technical re-equipment in construction industry tends toward the wide use of cellular concrete. The formulation and advantages of these materials were analyzed. The technological difficulties in their manufacture were mentioned. The most difficult problem is to ensure uniformity by quickly mixing the aerated concrete mixtures of components that differ in composition and mass fraction before the start of active gas formation, gas retention, and especially solidification. These difficulties can be eliminated by using the new technique of vibrojet mixing of both Bingham and Newtonian media. Forced high-frequency vibration actually increases the thixotropy of the mixture regardless of the number of components and their mass and physicomechanical properties. At the same time, monitoring the vibration parameters increases the circulation and interaction of the generated submerged jet flows. Rheological models were developed to determine the technical characteristics of the mixer vibrodrive and the process parameters. Supercomputer modeling of various scenarios of vibrojet mixing in the FlowVision program allowed visualization and optimization of modes to completely exclude stagnant zones in the mixer. In a full-scale experiment, test samples were prepared from the aerated concrete mixtures obtained by centrifuging and vibromixing. Their growth and strength characteristics were compared in accordance with GOST (State Standard) 10180-2012. The results showed that the new method for the preparation of mixtures and products from aerated concrete is highly effective.

A mathematical model of the dynamics of pressure swing adsorption was developed. The adsorption, aimed at separating multicomponent gas mixtures for hydrogen concentration, is performed in a four-adsorber unit with a CaA zeolite adsorbent. An original description of the mass transfer of the adsorbate (H₂, CO₂, CO) from the gas phase to the solid adsorbent for the mixed-diffusion region depending on the gas flow rate in the adsorbent bed was proposed. A computational treatment of the effects of the raw materials load and control variables on the dynamics of the cyclic adsorption process of gas mixture enrichment with hydrogen was performed. The problem of adaptive optimization of process variables was formulated and studied by modeling.

Theoretical foundations of technology for producing lithium carbonate of battery quality by the ammonia method have been developed. This technology is based on the precipitation of lithium carbonate from an aqueous solution of lithium chloride by its direct contact with a gaseous mixture of NH₃ and CO₂ in a 2 : 1 ratio, followed by NH₃ reproduction by the decomposition of ammonium chloride with calcium hydroxide, which is a byproduct of interactions in the LiCl−NH₃–CO₂−H₂O system. The applicability of the ammonia method for obtaining battery-quality Li₂CO₃ from sulfate, nitrate, and mixed lithium solutions has been shown.

A synthesis process of selective layered sorbent LiCl ⋅ 2Al(OH)₃ ⋅ nH₂O from a mixture of LiCl + AlCl₃ + NaOH + H₂O solutions with the formation of NaCl solutions in the final suspension with a concentration ranging from 0.5 to 4.0 mol/dm³ has been studied. The effect of various factors exerted on the chemical composition of the sorbent in the course of its synthesis has been analyzed. It is shown that the abrasion strength of the sorbent depends on the amount of NaCl impurities therein. Practical recommendations for the synthesis of the sorbent are given.

The phase equilibrium in the Ca(NO₃)₂–H₂O system at temperatures of 0 to –31°C is studied and the polytherm of calcium nitrate–solution ice crystallization is built, from which its melting capacity is calculated relative to ice under equilibrium conditions at different temperatures. The minimum effective temperature of using calcium nitrate as a deicing agent is determined experimentally. The corrosion activity of calcium nitrate solutions with respect to metals and alloys, as well as cement concrete, is investigated. It has been established that calcium nitrate does not attack metals, aircraft alloys, or cement concrete. According to the research results, it is concluded that anhydrous calcium nitrate can be recommended as a granular deicing agent for use on cement concrete and asphalt concrete runway pavements.

The results of experiments on preparing pure (marketable) salt from crude salt of ammonium perrhenate are presented; the pure salt is rigidly standardized in elements–impurities and rhenium by recrystallization, sorption, and membrane electrodialysis. AP-0 salt is obtained from solutions purified from elements–impurities by recrystallization, AP-00 salt is obtained by sorption, and the salt purer than AP-00 is obtained by electrodialysis. The advantages and disadvantages of each of the methods are specified.

The synthesis technology of a chemically pure nanodisperse precursor powder (10–12 nm) based on a tetragonal solid zirconia (t-ZrO₂) solution in the ZrO₂ system (Y₂O₃)–Al₂O₃ for restorative dentistry is developed. A ceramic material with a crystallite size of 60–65 nm is obtained; its phase composition, dispersion, microstructure, and physical and mechanical properties are investigated; and its low-temperature moisture aging structural stability is established.

Copolymerization of styrene with methyl or butylmethacrylates in road petroleum bitumen is studied. The copolymerization of the comonomers selected proceeds in the bituminous medium according to the same laws as in the mass and depends on concentration of the methacrylates. Polymer–bitumen composites, which can be potentially used as structural polymeric materials, have been obtained and studied.

An aqueous two-phase system based on polyethylene glycol-1500 and sodium sulfate for the extraction of a number of monocarboxylic acids from aqueous solutions has been studied. The influence of the phase contact time, system composition, the molecular weight of the polymer, and temperature on the quantitative characteristics of the interphase distribution of a number of aliphatic monocarboxylic acids has been investigated. Based on the results, it is concluded that these systems are effective for solving problems of the extraction, separation, and purification of carboxylic acids and they are promising as extraction systems for the extraction of metal salts in the presence of carboxylic acids.

Process parameters of the polymerization of a mixture of exo,exo- and endo,endo-dimethyl esters of norbornene-2,3-dicarboxylic acid in the bulk of the monomer under the action of a ruthenium catalyst of the Hoveyda–Grubbs type are developed. The effect of the concentration of the catalyst on the physical and mechanical properties of poly(norbornene-2,3-dicarboxylic acid dimethyl ester) is studied.

Experimental findings concerning the efficiency of the Moscow refinery process for thermal-oxidative cracking in goudron processing are given. It was shown that combining both the processes of partial oxidation of feedstock with oxygen and the cracking, the high degree of goudron conversion to motor distillates and other marketable products was attained without hydrogen. Optimum conditions for initiated cracking were found when motor fractions and road tar or furnace fuel oil were obtained simultaneously under continuous conditions.

Absorption extraction of C₅₊ hydrocarbons from formation gas of gas-condensate fields at the level of temperature of from –25 to –30°C was simulated. The following conditions were recommended during realization: absorbent by physical-chemical characteristics corresponding to hydrocarbons С₉/С₁₀, four theoretical contact stages in the absorber, and partial expenditure of absorbent of 20–30 g/m³. Techniques of low-temperature absorption and low-temperature separation were compared. Parameters were determined that allow developing a scheme of a process with the increased degree of extraction of hydrocarbons С₅₊ (over 99%), which are valuable petrochemical materials.

Under the conditions of preliminary treatment during the preparation to annealing of a mixture of Tuva clays with the dearsenation cake of the Khovu-Aksy dump sludge, the material was found to undergo a chemical process that forms nepheline. Based on the calculated Gibbs energies of the reactions, it was concluded that the reaction occurs at the minimum number of components in the system: silicate Na₄Mg₂Si₃O₁₀–kaolinite (kaolinite + orthoclase).

New prospective sources of valuable minerals, including substantial reserves of crystalline graphite, gold, platinum, rare earth elements, and diamondlike carbon, have been revealed by the authors in high-carbon rocks in the south of Russia’s Far East. A scheme has been developed for the hydrometallurgical recovery of strategic metals and extra-pure (99.98%) crystalline graphite, used as a base material for conducting plasma-chemical investigations, from graphite ore. As a result of the experiment, nanodiamonds have been recovered, which were presumably inherited from the natural graphite-containing rocks.

Investigations of composition, structure, and hardness of ultrafine-grained solid alloy WC–8Co–0.4VC–0.4Cr₃C₂ after treatment in a gaseous mixture of CO + CO₂ of compacts with a lack of carbon for 50 min at a temperature 650°C on the initial stage of liquid-phase sintering. It was found that at CO content of 72.5% in the gas mixture, conditions are created for replacing the initial carbon deficiency (about 0.3%) and obtaining two-phase ultrafine-grained carbide of stoichiometric composition, in which carbon and hardness are uniformly distributed over the depth of the samples. This alloy has the lowest porosity (2.5%) and the highest hardness (HV1941). It was found that an increase of up to 80% or a decrease of up to 0% of the CO content in a gas mixture leads to the formation of a lack of carbon (1.0%) or an excess of carbon (4.5%) on the surface of the samples. This leads to a significant decrease in hardness. It is shown that the change in the carbon content and hardness in the depth of the samples is much less than on the surface.

To modernize the extraction facility of the RT-1 plant, two flow diagrams for plutonium purification have been developed. In the first flow diagram, the Pu(IV)–Np(IV) valence pair is stabilized and both Pu and Np are stripped and, in the second flow diagram, the Pu(IV)–Np(V) valence pair is stabilized and only Pu is stripped. The problem of stabilizing the pair of the desired components in the required valence state is solved using reagents that had already been used at the RT-1 plant: hydrogen peroxide, hydrazine nitrate, and a catalyst (Fe). Both flow diagrams are adapted to the extraction facility of the plant with minimum changes in equipment and successfully pass extended process tests. As the result of this work, the volume and salt content of the raffinate are reduced.

Two processes of multistage extraction chromatographic separation of components (with and without recycling) are theoretically studied under various conditions of loading of a mixture to be separated to the apparatus. A mathematical description of the separation processes is presented. It is shown that the separation of components in the process with recycling requires an order of magnitude fewer equilibrium stages than separation in the process without recycling. Moreover, the productivity of the process with recycling, which is determined by the duration of loading to the apparatus, is an order of magnitude higher.

The semibatch multistage extraction chromatographic separation of a binary system of components has been experimentally studied under various conditions of loading of the mixture to the apparatus. An acceptable fit of the previously developed mathematical model of the process to the experimental results is determined.