The novelty of the paper is the analysis of the possibilities of reducing the operating costs of a mine water pumping station in an abandoned coal mine. To meet the energy needs of the pumping ...station and reduce the carbon footprint, “green” energy from a photovoltaic farm was used. Surplus green energy generated during peak production is stored in the form of green hydrogen from the water electrolysis process. Rainwater and process water are still underutilized sources for increasing water resources and reducing water stress in the European Union. The article presents the possibilities of using these waters, after purification, in the production of green hydrogen by electrolysis. The article also presents three variants that ensure the energy self-sufficiency of the proposed concepts of operation of the pumping station.
This paper represents the results of experimental studies of physical modeling of the underground coal gasification process in terms of implementation of design and technological solutions aimed at ...intensification of a gasification process of thin coal seams. A series of experimental studies were performed in terms of a stand unit with the provided criteria of similarity to field conditions as well as kinetics of thermochemical processes occurring within a gas generator. Hard coal (high volatile bituminous coal) was selected as the raw material to be gasified, as that coal grade prevails in Ukrainian energy balance since it is represented by rather great reserves. Five blow types were tested during the research (air, air–steam, oxygen–steam, oxygen–enriched, and carbon dioxide and oxygen). As a result, the effect of tightness of a gas generator on the quantitative and qualitative parameters of coal gasification while varying the blow by reagents and changing the pressure in a reaction channel has been identified. Special attention was paid to the design solutions involving blow supply immediately into the combustion face of a gas generator. The experimental results demonstrate maximum efficiency of the applied gas generator design involving flexible pipelines and activator in the reaction channel and a blow direction onto the reaction channel face combined with blow stream reversing which will make it possible to improve caloricity of the generator gas up to 18% (i.e., from 8.4 to 12.8 MJ/m3 depending upon a blow type). Consideration of the obtained results of physical modelling can be used with sufficient accuracy to establish modern enterprises based on the underground coal seam gasification; this will help develop more efficiently the substandard coal reserves to generate heat energy as well as power-producing and chemical raw material. The research conclusions can provide technical reference for developing a new generation of underground coal gasification technology.
Coal mining regions face significant challenges in transitioning towards climate neutrality due to their dependence on fossil fuel extraction. This research explores the potential of underground coal ...gasification (UCG) technology as a pathway towards climate neutrality in these regions. UCG involves converting coal in-situ into syngas, a cleaner-burning fuel, while mitigating greenhouse gas emissions. The study investigates the material-thermal parameters of the gasification process using the MTB SPGV software and analyzes the gas concentration and producer gas yield parameters in the “Stepova” Mine field of SE “Lvivvuhillia”. Additionally, technological solutions for achieving climate neutrality through carbon dioxide (CO2) utilization are proposed, focusing on pre-separation of CO2 from producer gas obtained during UCG. A technological scheme for CO2 utilization is presented, outlining the steps from gas extraction to storage and utilization in underground spaces. The proposed method offers a promising approach to mitigate CO2 emissions and optimize resource utilization in coalmining regions, contributing to global efforts for environmental sustainability and climate action.
Ukrainian electricity production sector is in a critical situation. It is necessary to increase the coal production to ensure the continuity of electricity production. In this paper, an analysis of ...coal mining in western Donbas, Ukraine, was presented. The crucial thing is to increase coal production in this region. The new calculation schemes were proposed to increase coal extraction in Donbas mines. The coal pillar parameters, which are necessary for the effective control of the rock pressure caused by the stooping, were substantiated. The obtained parameters for the coal pillars will allow extracting more coal, safely and quickly dismantling the mechanized complex and effectively protecting the ongoing mine work. The case study helps determine the coal losses because of pillar leaving and to improve the stability of the main haulage roads located in the zone of the stooping effect as well as to achieve additional coal production in the mine. Such a technological solution allows to extract the coal more fully at the final parts of the extractive columns and to obtain an additional economic effect. The increase in coal production in coal mines of western Donbas will increase the energy security of all Ukraine.
The purpose of this study was to develop a physico-mathematical model and technique for estimation of chemical bond stability depending on electric field intensity of an external point charge. A ...hypothesis for a possible physico-chemical mechanism of the formation of additional harmful gases in the rock destruction by blasting was proposed. The theoretical basis of the hypothesis is the method of theretical evaluation of bond energy depending on the distance to a point charge, the third Coulomb centre. The quantum-mechanical model for calculating the electronic terms of molecules makes it possible to solve problems associated with the determination of parameters of molecules under the action of various physical fields on the system under consideration. The model was approved for some diatomic molecules. The discrepancy between the experimental data and calculated data did not exceed 14%, which proves accuracy of the obtained results. The model can be used in the field of research into the causes of gas-dynamic phenomena in underground coal mines, in studies of the degree of stability of nanostructured components of coal under physical influences, and in the theoretical design of new compounds and structures in the field of nanomaterial science and nanotechnology.
The paper presents the results of analytical and experimental studies of the hydrodynamics of the translational−rotational motion of incompressible gas flow within a working space of a ...variable-geometry vortex heat generator. The terminal velocity and pressure have been identified analytically. The effect of vortex generation on the ratio of the parameters has been analyzed. A mathematical model has been developed with a simplified design scheme that simulates the movement inside a vortex channel with fixed elements. On the basis of mathematical modelling, the influence of the apparatus-constructive (AC) design of the working space of a vortex heat generator on the generation of vortices inside the apparatus has been analyzed. The influence of the main geometric and hydrodynamic parameters of the device on the indicators of its energy efficiency has been investigated. The obtained models show the critical regions where the most intense cavitation zones are possible. An analysis of the hydrodynamics of the incompressible gas motion within the working space of the newly designed vortex heat generator with variable geometry has helped define both the terminal velocity and pressure. In addition, the effect of the facility geometry on the generation of vortices favoring cavitation was determined. The model studies have been carried out in terms of liquid loading changes in the 0.001–0.01 m3/s range. The changes in a velocity field within a working channel have been analyzed for the channel geometry, where a cone angle γ is 0° to 25°, with 130, 70, and 40 mm widths for the working channel. It has been identified that a sufficient axial symmetry of the heat carrier along a vortex accelerator enables the heat carrier inlet through a turbulizing nozzle. The dependence of the nozzle area, the effect on the efficiency of the vortex heat generator angle of attack of the vortex accelerator, and the ratio of the length and diameter of the vortex zone of the heat generator to its energy efficiency in general have been defined experimentally. These studies could be instrumental in the design of vortex heat generators whose geometry corresponds to the current requirements concerning energy efficiency. It has been found that the geometry of the vortex accelerator improves the operation of the heat generator by 35% in comparison with similar available designs.
Experimental methods for determining a performance index of explosives are analysed: the methods of a ballistic pendulum, ballistic mortar, a lead block, and according to the volume of soil explosion ...funnel. It is defined that the determination of a performance index of emulsion explosives (EE) involves a set of significant features connected with a large critical diameter requiring the experiments with large-mass charges and resulting in refusal from the traditional methods of determining a performance index. Analytical methods for calculating an index of relative performance of explosives are analysed. Determination of the performance indices of explosives with the help of analytical methods helps identify considerable differences in the calculation results; in case of emulsion explosives the results are erroneously low at all. It is since analytical methods do not consider the brisant action of emulsion explosives. This paper represents the developed methodology of determining a performance index of explosives according to the degree of detonation velocity. The proposed methodology considers the key energy and detonation characteristics of explosives: heat and volume of the explosion products, density (thickness), and detonation velocity. The use of analytical methodology for calculating a performance index for all explosive types makes it possible to get correct results that are necessary for designing the parameters of drilling and blasting operations.
Sometimes in mining, it is necessary to combine different extracting technologies within one enterprise. So, in this paper, the analysis of scientific and technical mining operations with combined ...technologies is carried out, and the search for structure and their operation in the mining enterprise is performed. The processes and technological parameters of mineral extraction by two fundamentally different technologies are investigated in detail. Due to the introduction of additional technologies, it is possible to involve sub-standard reserves in the production process, and an algorithm for determining the technological parameters is developed. This algorithm consists of criteria that make it possible to find compatibility in the work of one or more development technologies while maintaining an effective level of extraction. To do this, all processes at the enterprise are grouped: by degree of exploration, feasibility and economic efficiency. For each of them, certain coefficients were determined on the example of the operation of two specific combined technologies: the extraction of uranium ores and coal. For each group of criteria, certain coefficients are identified that allow assessing the feasibility of applying technology in their area. Their product is a general coefficient of compatibility, which shows the feasibility of introducing additional technology at the enterprise with the feasibility study. It defines the amount of funds invested in the development of an enterprise to achieve efficient mineral extraction with combined technologies within one enterprise. This point can be used to predict the grade variability of stockpiles from the origin source and the methodology allows characterizing the iron grades within stockpiles without any extra sampling.
The paper presents an experimental study on the formation process of burden surface texture on the blast furnace throat and its influence on the radial distribution of gas flow. The study was ...performed with the application of blast furnaces equipped with a bell-type charging device using radio-isotope means for the control of burden surface texture (profile) and burden surface level, i.e., gamma locators for burden surface texture. The study was carried out under the conditions of an operating blast furnace in an iron and steel plant using a unique GEOTAPS system for automated control of geometric and temperature parameters of burden material surface on the blast furnace throat. The influence of the surface texture on the gas flow distribution was also investigated. The possibility of a self-stabilization effect for burden surface texture and gas flow in an operating blast furnace under suitable conditions was experimentally proven. As a result of the experimental study performed, four ways of energy-saving technology implementation were determined for the control of blast furnace melting based on the data on the burden surface texture and previously unknown regularities of surface layer formation of burden material on the throat of an operating blast furnace with a bell-type charging device. The main idea of the paper is the development of automated control for the radial distribution of burden material and gas flow using actual or predicted surface texture parameters as important intermediate factors that both describe the process and have a significant simultaneous influence on it.
The use of similarity theorems for simulation of the technological process of mineral extraction is considered. The list of parameters that significantly influence the process of underground leaching ...of minerals is defined. Using these parameters and fundamental laws of physics and chemistry, mathematical functions are determined to describe the processes’ behaviour under these conditions. The obtained mathematical functions make it possible to develop a computer model of polymetallic ores leaching. This allows for the prediction of the volume of extracted concentrate with minerals from the ore mass with the associated compounds. The obtained results of calculations showed a change in the volume of minerals extracted from the rock mass depending on the mass of the working agent, the volume of leached ore and the solvent percolation rate. The results of the research can be used at mining enterprises to extract polymetallic ores by underground leaching. Also, they allow for the estimation of the economic issues from mining the ore reserves.
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