Kazan State Power Engineering University

Surfactant-based microemulsions are widely used for effective encapsulation of various substances, as delivery vehicles for physiologically active compounds, and the media for chemical and biochemical reactions. Their structure and properties affect the efficiency of required tasks. The paper considers the phenomenon of reverse micelle clustering and temperature changes in the process of substance transfer in the volume of surfactant-based microheterogeneous systems. A comparison of clustering and effects of diffusion transfer of substances in microemulsions of surfactants with different structures, viz., anionic sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and cationic cetyltrimethylammonium bromide (CTAB), was carried out. It was found that structural morphology of surfactant molecules, which determines the conditions of contact between surfaces of reverse micelles, the likelihood of water channel formation between them, and the composition of the dispersed phase, has a dominant influence on the structure and properties of water-in-oil microemulsions. Butanol, used as a cosurfactant in the CTAB-based microemulsion, was shown to partially dissolve in decane, carrying with it some of the water.

Experiments are conducted on liquid (water) heating by hot vapor in a plate-type heat exchanger. The coolant agent temperature and flow rates are measured; the heat balance and heat transfer equations are applied for calculating the heat flux and the heat transfer coefficient as a function of flow rate for heated water. The mathematical models are developed for the thermal number of transfer units and for liquid displacement in a smooth duct. A cell model for coolant flow patterns using the surface-type heat transfer enhancers (wire inserts) and volumetric enhancers (chaotic packing) is developed. The calcuations and experimental data are in satisfactory agreement with each other. Experimental and modeling methods demonstrated that the use of surface-type enhancers in a problem of high-viscosity liquid heating (e.g., industrial oil) increases the heat transfer coefficient by 2.75 – 6 times and the gain in thermal efficiency is about 2.4 – 3.2 times. The gains from using the volumetric-type enhancers are 15 – 20 times and 2 – 3 times, respectively, for heating with hot water. The developed mathematical model with accounting for flow patterns can be applied in design or modernization of heat transfer apparatuses in various industries.

The possibility of using inductive plasma to activate the sorption properties of granulated high-moor peat with respect to petroleum products was investigated. Plasma conditions were created using a high-frequency (HF) inductive plasma torch (operating frequency 27.12 +/- 0.27 MHz) at atmospheric pressure using argon as the plasma-forming gas. Based on the recorded argon plasma emission spectra, the component composition of the plasma flow during granule surface treatment was determined. The presence of OH radicals was detected, which have a destructive effect on the organic matter of peat, leading to changes in surface morphology. According to electron microscopy data of the fibrous structure of the peat matrix, a network of small capillaries is formed on the surface of the fibers, which significantly increases the surface area of granulated peat available for interaction with petroleum products. The degradation process of plasma-treated peat granules was studied using thermogravimetric analysis. The results showed that when heated in a nitrogen flow, three stages form on the mass loss curves: dehydration (50-200 degrees C), decomposition of peat organic matter (210-500 degrees C), and coal oxidation (700-770 degrees C), which determine the sample morphology. The relationship between the sorption properties and morphology of modified peat granules was investigated. The oil capacity of peat sorbents for turbine oil was determined depending on their processing conditions.

PURPOSE. Determination of quantitative characteristics of nitrogen oxide emissions during combustion of gas mixtures containing hydrogen, carbon monoxide and methane.RESULTS. Several types of gases with different chemical compositions and quantitative content of components were considered: CH4; CO; H2; 7 types of synthesis gas with different content of CH4, CO, H2, CO2, N2. These types of synthesis gas had low, medium and high values of heat of combustion. When performing numerical studies of the parameters and composition of combustion products, an approach based on the chemical equilibrium state of a multicomponent reacting mixture at a minimum value of isobaric-isothermal potential was used. The values of the main parameters of combustion products and estimates of nitrogen oxide emissions were obtained at different ratios of the initial components in the gas mixture and different values of the excess air coefficient. The values of the relative indicators of combustion product consumption correlate quite strongly with the values of the relative indicators of nitrogen oxide emissions.CONCLUSION. Numerical estimates of the relationship between the combustion heat of generator gases, the flow characteristics of the combustion products determined by the composition of the initial gas mixture, and nitrogen oxide emissions are obtained. The quantitative indicator Wps, determined by the ratio of the mass flow rates of the combustion products of the base fuel and alternative generator gas, under the condition of the same thermal power of the power plant, makes it possible to preliminary compare the expected level of NOx emissions. At Wps ≈ 1, the level of NOx emissions for the compared fuel compositions is approximately the same. Accordingly, at values of this indicator greater or less than one, the levels of nitrogen oxide emissions during combustion of the alternative generator gas are higher or lower than during combustion of the base fuel. The practical use of the Wps indicator is most effective at the stages of development and design of new power plants, including optimization of planning of computational and full-scale experiments, as well as during the transfer of operating power plants to alternative gas fuel.

This study presents a comprehensive analysis of technological considerations in the fabrication of solid oxide fuel cells (SOFCs) optimized for low-, intermediate-, and hightemperature operation. The research evaluates the applicability of commercially available ceramic materials and established fabrication techniques. Fundamental physicochemical operating principles of SOFCs are examined, and correlations between material selection for the anode, cathode, and electrolyte components and the resulting electrochemical performance are established. The most promising materials for each component are identified. Furthermore, a comparative assessment of power densities across SOFC configurations based on these materials is provided, accompanied by a detailed evaluation of production costs for each configuration.