The aim of this work is to create the scientific foundations of microwave extractors implementing the effect of mechanodiffusion discovered by the authors, as well as visual, kinetic, and energy substantiation of the fundamentals of mechanodiffusion, and optimization of the operating parameters of this process. To achieve this aim, a concept of innovative extractors has been formulated — sequential reduction of the extractant layer on the surface of the solid phase. Comprehensive experimental studies have been conducted, and the time of rational energy use has been determined. A model is presented that makes it possible to determine the operating mode of the extractor depending on the specific power of the generators. A methodology for the calculation and optimization of microwave extractors with the objective function of minimum energy consumption is presented. An example of estimating energy overconsumption is given. A scientific and technical hypothesis for the creation of innovative extractors that would solve traditional problems is formulated. The most significant result of the work is that the foundations for the design and optimization of energy-efficient continuous microwave extractors have been created, making it possible to obtain polyextracts in a single apparatus. The significance of the work lies in the development of mechanodiffusion theoretical foundations and the proposal of engineering methods for optimization of microwave extractors. The result is an electrodynamic extractor that could be of commercial interest in the cognac industry.
This article presents operational data from turboexpander units (TEU) wherein a stable temperature gradient across both the turboexpander and the turbocompressor coexists with its power imbalance. A hypothesis attributing this phenomenon to internal gas internal subflows within the TEU flow path is proposed. The primary objective is to investigate the effect of such internal subflows on the power balance of a TEU configured as an expander-compressor unit and to substantiate the necessity of accounting for this effect during parametric diagnostics. Analytical power balance relations for the compressor and expander are formulated, incorporating potential gas internal subflows through diverse structural elements of the flow path. These relations are subsequently validated against gas-dynamic test data. Establishing that the computed power imbalance between the turbine and compressor may originate from internal subflows induced by wear of flow-path components enables the identification of critical assemblies requiring heightened attention during both design and operational phases, thereby informing future design improvements. Furthermore, prospective enhancements to the proposed methodology are examined within the framework of integrating TEU parametric diagnostic systems with big data analytics. The most significant outcome is the quantification of specific gas internal subflows exerting the greatest influence on the compressor-turbine power balance ratio, along with an upper-bound estimate of this influence. The scientific and practical relevance of these findings lies in augmenting TEU operational efficiency and reliability, providing a basis for design optimization, and enabling advanced performance monitoring methodologies.
The objective of this study is to enhance the energy efficiency and environmental safety of boiler plants and engines equipped with waste heat recovery boilers. This objective is achieved by utilizing water-fuel emulsions as fuel for these boilers and engines. Using an experimental setup configured for the preparation and combustion of both standard fuels and water-fuel emulsions, the influence of the quality and composition of these emulsions on corrosion processes affecting heat exchange surfaces was investigated. The studies were conducted using emulsions with a water content ranging from 2% to 30%, fuels with a sulfur content of 0.98% to 2%, and an excess air ratio of 1.01 to 1.5, covering a tube wall temperature range of 70 degrees C to 150 degrees C. The most significant outcome of this study is the data demonstrating the absence of a corrosion peak and a substantial reduction in the corrosion penetration rate to acceptable levels (0.2...0.3 mm/year) when using emulsions with a 30% water content across aAbroad range of excess air ratios (1.01-1.15). Under these operating conditions, a passivation effect was also observed on the surfaces of the carbon steel boiler tubes. The significance of this research lies in the fact that the technology prevents or mitigates low-temperature corrosion on heat exchange surfaces, thereby enabling increased heat recovery from flue gases in boiler systems. For waste heat boilers in marine diesel engines, the heat recovery efficiency increases by 10-15%, as the exhaust gas temperature decreases from the design range of 160-180 degrees C to values of 130-150 degrees C.
This article examines the startup period of a natural gas pipeline cryogenic reduction unit (CRU) within a gas distribution station (GDS). The objective of the study is to determine the temperature distribution within a regenerative heat exchanger (RHE) during the CRU's initial cooling stage. This objective was achieved through an analysis of primary cooling methods for the regenerator packing and through numerical experiments to determine the optimal filtration rate and switching time. The study involved a CRU operating on a simple throttling cycle and using RHE. The numerical experiments yielded the optimal filtration rate and blast duration for the natural gas pipeline. Software was developed using a mathematical model of the CRU and implemented in the Python programming language. The most important result is the shape of the temperature distribution curve across the packing bed height during the initial startup of the CRU. Based on the research conducted, it has been shown that increasing the steady-state operating time of the CRU is accompanied by an expansion of the zone of active heat transfer to the upper portion of the packed heat exchanger. The significance of these results lies in the development of a methodology for studying the formation and height distribution of temperatures within the CRU's regenerative heat exchanger. This allows for an analysis of its operating efficiency during the initial cooling period and paves the way for further research under conditions of daily uneven gas consumption in the city network.
The aim of this study is the early detection of developing insulation defects in high-voltage oil-filled bushings based on the analysis of the temporal behavior of diagnostic indicators rather than only their comparison with threshold values. To achieve this aim, insulation indicators are interpreted as time curves, and data processing is performed using curve recognition methods that identify charac-teristic patterns of parameter variation. The most important results demonstrate stable differences between different technical conditions. Serviceable bushings are characterized by the absence of a statistically significant relationship with service duration while maintaining consistent internal dependencies and a high similarity of time curves on adjacent phases caused by common operating conditions. For defective bushings, statistically significant relationships between individual indica-tors and service duration are identified, changes in the internal correlation structure are observed, and similarity with the indicators of neighbouring serviceable bushings is absent. Based on the recognition of the shapes and mutual consistency of time curves, a decision rule is formulated: a defect is diagnosed when correlation with time and internal correlations are present, while cross-phase correlation is simultaneously absent. The significance of the obtained results lies in the fact that the application of curve recognition methods enables the detection of developing defects before the indicators exceed threshold values, reduces the probability of erroneous rejection, and increases the reliability of bushing condition assessment under various network operating modes. The pro-posed approach can be used in technical condition monitoring systems to improve the efficiency of operational maintenance of high-voltage equipment, leading to reduced failure risks and more justified maintenance planning.
