Theoretical Foundations of Chemical Engineering最新文献

The conversion of sulfocationite from the ({text{NH}}_{4}^{ + }) form to the H⁺ form is studied. It is shown that when using concentrated solutions of strong mineral acids (nitric, sulfuric), the conversion is ineffective. In order to achieve efficient conversion to the H⁺ form, it is recommended to treat the sulfocationite in the ({text{NH}}_{4}^{ + }) form in two stages: first with a sodium salt solution to convert it to the intermediate Na⁺ form, then with a strong mineral acid solution to obtain the sorbent in the H⁺ form. An equation is proposed for calculating the specific reagent consumption required to achieve a certain degree of the sorbent conversion.

Like any technical system, robotic milking units require appropriate technical servicing due to the wear and subsequent failure of functional system components. At present, the import of spare parts into the country has been discontinued, including teat cup liners and elastomer components of the pump line, which are manufactured from elastomer compounds. The primary technological parameter of any compound is its viscosity, which affects processability. This study examined the viscosity of several grades of silicone compounds and derived mathematical relationships describing the dependence of compound viscosity on temperature.

Stable Pickering emulsions of the first type based on the epoxy oligomer CHS-EPOXX 530 were obtained in the presence of micro- and nanosized aerosil particles, exhibiting resistance to both coagulation and sedimentation. The dependences of rheological properties on oligomer concentration, phase volume ratio, and content of the solid stabilizing powder (aerosil) were determined. In particular, increasing the aerosil concentration led to enhanced interparticle interactions, which caused an increase in the effective viscosity of the emulsions and subsequent breakdown of the formed coagulation–thixotropic structure under low shear deformation, followed by quasi-Newtonian flow behavior. The influence of these factors on the physicomechanical properties of the resulting coatings and films produced from these emulsions was also established. The data obtained confirm the good film-forming properties of such emulsions and support their potential use as polymeric film formers in the production of paint and varnish materials containing a limited amount of organic solvents, as well as in two-component carbon fiber-reinforced adhesive formulations for the repair of structural concrete elements.

Phase equilibria in sections of the MgCl₂–CO(NH₂)₂–H₂O system at temperatures below 0°C are studied. It is established that the introduction of urea into the MgCl₂–H₂O system leads to the formation of low-temperature eutectics with crystallization temperatures down to –51°C, which significantly expands the temperature range of application of magnesium chloride as an anti-icing material. The identified compositions are promising for the development of new anti-icing materials on their basis.

The mineral composition of andesibasalt from the northeastern slope of the Urals, basalt-dolerite (Kanzafarov quarry, Chelyabinsk oblast), and gabbro (Navolok deposit, Republic of Karelia) was calculated by computer-based physicochemical modeling and determined experimentally. A comparison of the results and capabilities of different methods for determining the mineral composition of rocks from the gabbro–basalt group is presented.

Computer modeling was carried out for the primary separation of direct synthesis products of methylchlorosilanes. The developed control scheme for process parameters under feed flow fluctuations ensures the production of stable-quality products: 99.963 ± 0.004 wt % methyl chloride in the recycled methyl chloride and 0.0475 ± 0.0015 wt % methyl chloride in the crude methylchlorosilanes.

The paper presents the results of studies of the sorption properties of layered double hydroxide of the composition Mg₄Al₂(OH)₁₂CO₃⋅3H₂O, obtained by the solid-phase interaction method, with respect to the ({text{PO}}_{4}^{{3 - }}) ion. It is found that the sorption process is most adequately described by the Langmuir monomolecular adsorption equation, and its kinetics is described by a pseudo-first-order equation. The activation energy of the process is determined, based on which is concluded that the process occurs in the diffusion region.

The article is devoted to the theoretical study of chemical reactions occurring in the first step of the pyrolytic decomposition of the methylchlorosilane molecule. The most probable decomposition reactions of methylchlorosilane and their mechanisms were identified, a thermodynamic calculation of the products and transition state structures at different temperatures was performed, and the equilibrium and rate constants of the reactions were calculated.

Phase transformations in fly ash from the concentration plant of the Norilsk Mining and Metallurgical Combine were examined by X-ray microanalysis and X-ray diffraction phase analysis during gas-phase treatment in a HNO₃ (vapor)–air atmosphere, followed by treatment of the resulting products with water.

The aim of this work is to describe the design and application of a compact portable proton nuclear magnetic resonance (NMR) flow analyzer for manual and stationary rapid monitoring of crude oil and wastewater characteristics along production lines. The advantages of the NMR method and instruments based on it over the closest analogs are discussed. A brief overview of the theory of proton NMR relaxometry, the measurement technique, and the metrology of the method is given. The design and main components of the analyzer are described, as well as the technologies for representative sampling and instrument control. Correlations between hydrocarbon characteristics and proton NMR relaxation parameters were established to support the development of flow-based rapid monitoring technologies using these parameters. Equations were obtained linking proton NMR parameters with the properties of chemical products, including molecular weight and oil concentration in wastewater.