Theoretical Foundations of Chemical Engineering最新文献

{"title":"Study of Micromixing in a Microreactor with Counter-Current Intensively Swirled Flows","authors":"R. S. Abiev,&nbsp;A. K. Kudryashova","doi":"10.1134/S0040579525600202","DOIUrl":"10.1134/S0040579525600202","url":null,"abstract":"<p>A comparative study of micromixing in a microreactor with counter-current intensively swirling flows (MRISF-CC) is performed for different methods of flow feed using the iodide–iodate technique. The dependence of the micromixing quality (the so-called segregation index) on the specific energy dissipation rate is found for three methods of feeding solutions to the device. In the first and second methods, the solutions are fed to the tangential and axial nozzles of the left and right chambers of the device, respectively (corresponds to the mixing conditions in the single-stage microreactor MRISF-1). In the third case, the solutions are fed to two tangential nozzles and both flows are intensively swirled and mixed in a limited volume, while the axial and circumferential velocity components are directed towards each other. In the third case, the quality of micromixing was up to ten times higher (at a given value of the specific energy dissipation rate) than in the first two cases, and up to 2400 times higher than in a device with a magnetic stirrer. Thus, the implementation of mixing of counter swirling flows provides improvement in the quality of micromixing compared to other types of microreactors with swirling flows. The effect of reducing the exponent to ≈2.2 in the formula relating the specific energy dissipation rate to the total flow rate of solutions has been found, which can be explained by the mutual damping of the angular momentum during the interaction of two vortices. The obtained results make it possible to explain the influence of the micromixing conditions on the synthesis of nanosized particles from solutions.</p>","PeriodicalId":798,"journal":{"name":"Theoretical Foundations of Chemical Engineering","volume":"58 4","pages":"1082 - 1097"},"PeriodicalIF":0.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Critical Phenomena of Rheodynamic Origin in the Process of One-Sided Cold Pressing of Powder Materials","authors":"A. M. Stolin,&nbsp;P. M. Bazhin,&nbsp;L. S. Stelmakh,&nbsp;P. A. Stolin","doi":"10.1134/S0040579525600305","DOIUrl":"10.1134/S0040579525600305","url":null,"abstract":"<p>In this paper, a comparative analysis is carried out of the kinetics of compaction of a powder material in the process of one-sided cold pressing for different modes depending on the externally set conditions for the movement of the press plunger: the modes of constant specified force or speed. It is shown that in the constant speed mode, a critical phenomenon is realized on the press plunger, which is accompanied by a progressive increase in pressure over time, ensuring a sharp increase in the compaction speed. As a result, after a certain period of induction, the compaction process begins to accelerate automatically over time. The described situation has a physical analogue of combustion and explosion. This circumstance allows us to introduce new ideas into the theory of powder material pressing processes. Based on numerical calculations, it is established that the dependence of the press plunger speed on the voltage on it has a non-monotonic nature, which is due to the competitive influence of the dynamic factor: the loads and dependence of the bulk viscosity on density. It is shown that in the given force mode, a “harmful effect” occurs: progressive auto-braking of the compaction process over time. The conducted analysis allows us to develop specific recommendations for predicting rational modes of one-sided pressing of powder materials.</p>","PeriodicalId":798,"journal":{"name":"Theoretical Foundations of Chemical Engineering","volume":"58 4","pages":"1187 - 1192"},"PeriodicalIF":0.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Viscous Fingering in Supercritical Fluid Extraction","authors":"A. A. Salamatin,&nbsp;A. S. Khaliullina,&nbsp;M. V. Kalinina","doi":"10.1134/S0040579525600317","DOIUrl":"10.1134/S0040579525600317","url":null,"abstract":"<p>The paper investigates the issue of viscous fingering under conditions of supercritical fluid extraction of oil from ground high-oil raw materials. The concentration profile of the filtered solution is a solution of the reaction–diffusion equation and represents a traveling wave. The width of the zone where the main concentration difference occurs is much smaller than the height of the apparatus. Using a small parameter, the boundary layer expansion in the vicinity of the concentration front is constructed and the hydrodynamic stability of the surface separating the depletion zone and the saturated zone is investigated. Within the framework of the normal mode method, a dispersion relation is obtained. Limitations on the hydrodynamic parameters under which the front remains stable to small disturbances are determined.</p>","PeriodicalId":798,"journal":{"name":"Theoretical Foundations of Chemical Engineering","volume":"58 4","pages":"1193 - 1205"},"PeriodicalIF":0.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of Mathematical Models of Non-stationary Heat (Mass) Conductivity Processes in Bodies of Canonical Form","authors":"S. V. Fedosov,&nbsp;M. O. Bakanov","doi":"10.1134/S0040579525600470","DOIUrl":"10.1134/S0040579525600470","url":null,"abstract":"<p>Currently, there are a large number of materials that are subject to thermal effects during their production; from the point of view of the principles of geometry, their shape can be reduced to classical bodies of canonical shape: plate, cylinder, or sphere. During thermal treatment of solid materials (heat and moisture treatment, drying, firing), the transfer potentials (temperature, mass content) change critically with respect to the process time. When solving boundary value problems of heat and mass (moisture) conductivity in similar cases, it is proposed to use the “zonal” method and the “microprocesses” method. The main positions of the “microprocesses” method, as applied to the modeling of boundary value problems of heat and mass transfer for bodies of canonical shape under boundary conditions of the first kind (Dirichlet conditions), are presented in the previous works of the authors [1–3]. The current paper presents a methodology based on the “microprocess” method for solving boundary value problems of heat and moisture conductivity under more general boundary conditions, conditions of the third kind (Riemann–Newton). The high adaptability of these conditions lies in the fact that, depending on the values of the Biot number (Bi), they are transformed into a condition of the first (Bi → 0) or second (Bi →∞) kind. The paper shows that for mathematical modeling of heat- and mass-transfer processes in systems with a solid phase based on the “microprocesses” method, it is promising to search for solutions in the region of small values of the Fourier numbers (Fo &lt; 0.1). Mathematical calculations for solving the corresponding boundary value problems are presented and examples of the results of their numerical implementation are shown. The solution to the problems of heat conduction and diffusion for bodies, including those of canonical form, is obtained in the form of Fourier series, which is typical for conditions with an uneven initial distribution of the heat- and mass-transfer potentials of matter, but solutions for small values of the Fourier numbers are not given in the sources. At the same time, with a decrease in the process time, the numerical values of the Fourier criteria also decrease and thus the number of members of the infinite series increases, which entails an increase in the error in the subsequent calculations. The paper presents solutions for bodies of canonical shape—plate, cylinder, and sphere—and also presents nomograms of the dimensionless temperature of the body surface depending on the values of the Biot and Fourier numbers for specific values of the number Bi.</p>","PeriodicalId":798,"journal":{"name":"Theoretical Foundations of Chemical Engineering","volume":"58 4","pages":"1359 - 1369"},"PeriodicalIF":0.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling of the Flotation Process in an Industrial Apparatus","authors":"N. A. Martsulevich,&nbsp;A. V. Kazakov,&nbsp;O. M. Flisyuk","doi":"10.1134/S0040579525600159","DOIUrl":"10.1134/S0040579525600159","url":null,"abstract":"<p>A relation for the effective mixing coefficient is obtained, which allows taking into account the scale effect when modeling mass-transfer processes in large-diameter devices within the framework of a one-dimensional diffusion model. The ratio explicitly takes into account the dependence of the value of the specified coefficient on the transverse unevenness of the hydrodynamic and concentration fields. Using the specified ratio, the process of flotation purification of industrial wastewater from oil-containing compounds was simulated. Comparison of the calculation results with the performance indicators of the flotation units at the Kirishi oil refinery proved the adequacy of the proposed model representations to the real industrial process.</p>","PeriodicalId":798,"journal":{"name":"Theoretical Foundations of Chemical Engineering","volume":"58 4","pages":"1036 - 1041"},"PeriodicalIF":0.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Choosing Rational Technologies for the Final Purification of Wastewater from the Production of Protective Coatings and Printed-Circuit Boards","authors":"E. A. Uretskii,&nbsp;I. V. Nikolenko,&nbsp;V. V. Moroz,&nbsp;T. I. Akulich","doi":"10.1134/S0040579524601973","DOIUrl":"10.1134/S0040579524601973","url":null,"abstract":"<p>A number of versions of a process flow diagram for the post-treatment of wastewater from the production of protective coatings and printed circuit boards are considered. It is shown that the choice of water treatment flow diagram depends mainly on the quality of the initial wastewater composition and on the requirements for the treated water. In this case, the simplest solution to the problem consists in separating the flows of the least polluted wastewater and in returning them after treatment to the lines of industrial water supply. As an alternative solution, joint reagent treatment of all the types of wastewater followed by post-treatment with the use of ion-exchange methods is proposed. However, staged wastewater treatment, wherein water is prepared in accordance with the technological requirements for the corresponding industries may represent a more flexible and cost-effective system.</p>","PeriodicalId":798,"journal":{"name":"Theoretical Foundations of Chemical Engineering","volume":"58 4","pages":"1327 - 1333"},"PeriodicalIF":0.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intensification of Mass Transfer in a Gas–Liquid Apparatus with a Mixer","authors":"N. A. Voinov,&nbsp;A. S. Frolov,&nbsp;A. V. Bogatkova,&nbsp;O. P. Zhukova","doi":"10.1134/S0040579525600287","DOIUrl":"10.1134/S0040579525600287","url":null,"abstract":"<p>A new method for dispersing gas from an open vortex cavity into localized zones with reduced pressure in the liquid behind rotating mixer blades is studied. The optimum distance between the blade mixers on the shaft, which ensures the intensification of mass transfer with lower power consumption for mixing, is established. The conditions allowing for an increase in the mass-transfer coefficient are demonstrated and confirmed through numerical simulation. The experimental values of power, gas content, bubble diameter, and mass-transfer coefficient in the apparatus with the mixer implementing the proposed dispersion method are presented.</p>","PeriodicalId":798,"journal":{"name":"Theoretical Foundations of Chemical Engineering","volume":"58 4","pages":"1166 - 1175"},"PeriodicalIF":0.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of Fractionation and Extractive Distillation for Separation of Butyl Propionate–Propionic Acid–Butyl Butyrate–Butyric Acid Mixture","authors":"T. V. Chelyuskina,&nbsp;F. N. Bedretdinov,&nbsp;S. A. Potemin","doi":"10.1134/S0040579525600184","DOIUrl":"10.1134/S0040579525600184","url":null,"abstract":"<p>A flowsheet for the separation of a butyl propionate–propionic acid–butyl butyrate–butyric acid mixture into individual components was developed. The flowsheet contains a fractionating column and units for extractive distillation of the biazeotropic constituents butyl propionate–propionic acid and butyl butyrate–butyric acid using sulfolane as a separating agent. The mutual arrangement of various isomanifolds was studied in the phase diagrams of the derived separation systems of butyl propionate–propionic acid–sulfolane and butyl butyrate–butyric acid–sulfolane. It was found that their arrangement is favorable for carrying out the extractive distillation process. By analyzing the relative volatility diagrams of the components of the biazeotropic mixtures in the presence of sulfolane, the ratio of the amounts of the separating agent and the initial mixture that is required to implement the separation was selected. The operating parameters of the columns of the flowsheet were determined, ensuring the purity (mole fraction) of individual components of at least 0.9950 at minimum energy consumption in the reboilers of the columns.</p>","PeriodicalId":798,"journal":{"name":"Theoretical Foundations of Chemical Engineering","volume":"58 4","pages":"1064 - 1072"},"PeriodicalIF":0.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mathematical Modeling of the Process of Grinding Materials","authors":"E. M. Koltsova,&nbsp;M. A. Babkin,&nbsp;N. A. Popova,&nbsp;A. V. Zhensa","doi":"10.1134/S0040579525600172","DOIUrl":"10.1134/S0040579525600172","url":null,"abstract":"<p>Based on knowledge of thermodynamic flows and driving forces of the crushing process and the application of the principle of minimum entropy production a dependence for determining the size of particles resistant to crushing was obtained and verified using experimental results on grinding corundum in a planetary mill. To model the kinetics of grinding, an integrodifferential equation for the balance of the number of particles by linear dimensions was obtained, where the probability of particle crushing was determined from the physicochemical essence of the thermodynamic crushing flows. The results of calculating the density of the distribution function of the number of particles and the change in the average size of corundum particles during grinding over time are presented, which agree well with the experimental data. Optimal modes for carrying out the process of grinding corundum in a planetary mill to obtain particles of a given size have been found.</p>","PeriodicalId":798,"journal":{"name":"Theoretical Foundations of Chemical Engineering","volume":"58 4","pages":"1055 - 1063"},"PeriodicalIF":0.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis of ACS Digital Equivalent by the Ethylbenzene Dehydrogenation Process","authors":"A. P. Popov,&nbsp;S. G. Tikhomirov,&nbsp;S. L. Podvalny,&nbsp;O. V. Karmanova,&nbsp;V. K. Bityukov,&nbsp;O. G. Neizvestny","doi":"10.1134/S0040579525600299","DOIUrl":"10.1134/S0040579525600299","url":null,"abstract":"<p>The article considers the main stages of evolution of the mathematical model of the physico-chemical stages of catalytic dehydrogenation of ethylbenzene during styrene production. The new structural elements of the mathematical model describing the chemical processes of heat exchange and ethylbenzene dehydrogenation are presented. The introduction of additional mathematical dependences makes it possible to reduce the number of structural and parametric uncertainties characteristic of previously known models of dehydrogenation kinetics. A system of logically interconnected models is developed as a digital equivalent of an automated process control system. The synthesis of the digital predictive control system equivalent within the model-oriented design concept framework is described. A method for synthesizing hierarchical models of chemical–technological systems is proposed. A software emulation of the automated control system of the process under study is performed. The results of computer implementation of the digital equivalent in the form of predicted trajectories of changes in the parameters of the state of the technological process, reaction medium, and catalyst are presented.</p>","PeriodicalId":798,"journal":{"name":"Theoretical Foundations of Chemical Engineering","volume":"58 4","pages":"1176 - 1186"},"PeriodicalIF":0.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}