• Energy Research

The paper represents the analysis, which has helped to establish the usage of gas hydrate technologies in the methane conversion. This gas could be obtained in different ways. Possibilities and sources for the gas obtaining have been demonstrated. Use of other environmentally friendly sources to support operation in such systems in terms of joint energy complex has been considered. The necessary kinetic connections to provide operational sustainability of all the constituents have been given. The approach helps evaluate quantitatively the priority of its physicochemical transformations to obtain gas hydrates artificially. It is possible to transport methane at considerable distances when it is solidified. Actually, in this case there is no necessity to build costly compressor stations and pipelines for its transportation to consumers. The approach is extremely important for mining regions as it helps prolong the operating period and working out of the abandoned and off-balance coal reserves. In this case, it is proposed to apply special gasification technologies tending to maximum methane recovery. The proposed solutions give the possibility to define the trends of our further research. They will be highlighted in the following authors’ studies.

Topical issues concerning the possibilities of effective energy generation on the basis of Ukrainian mining enterprises have been highlighted. Attention is drawn to one of the most challenging tendencies of nontraditional energy sources development in the process of wind-driven powerplant use. The plants consume energy of technogenic air flows. Operation schemes and engineering solutions as for the possibilities to involve nontraditional sources of energy resulting from operation of technogenic objects and industrial structures of enterprises (i.e. stopes, mine dumps, industrial facilities etc.) in power balance of a mining enterprise have been demonstrated. Energy efficiency of the wind-driven powerplants in the context of different operation schemes aimed at utilization of energy of technogenic air flows has been analyzed. Output of a wind-driven system as a component of technological segment of a mining enterprise making it possible to meet 20 to 44% of its power demand has been determined. The objective of the paper is to substantiate process solutions as well as technical and engineering ones as for the obtaining nontraditional energy sources basing upon introduction of wind-driven power plants.

This paper contains the research conducted within the grant No. 0120U102084 (financed by the Ministry of Education and Science of Ukraine), and Dubrovnik International ESEE Mining School (project in the framework of EIT Raw Materials).

This work was supported by the Ministry of Education and Science of Ukraine, grants No.0116U008041 and No.0117U001127.

Mining systems for ore deposit extraction with the backfilling of the goaf solve the problem of preserving the surface and the complete extraction of rich ores. This paper considers the filling of mined-out stopes with a viscous fluidal solution for the formation of an artificial strong massif, which results in a conglomerate formed on contact with the ore deposit. It was established that exogenous fracturing at the Pivdenno-Belozirske deposit significantly affects the stability of the sides and ceilings in the chamber. This phenomenon can be observed at the first stage of processing. At chambers (the second stage of processing), the artificial rock mass is exposed. It has been established that the chamber mining systems do not ensure the operational stability of the vertical outcrop in the zones of exogenous intensive fracture of the rock mass, especially in the places where they intersect. The zonal location of intense fracture was established along the strike and dip of the steep ore deposit, as was its importance in the formation of rock fallouts. An analytical solution algorithm has been developed to determine the penetration of the backfilling mixture in the plane of the intersection of zones of intense cracking, with opposite azimuths of incidence at steep angles of macrocracking. The features of penetration into microcracks of the backfilling mixture used at the mine, which are affected by their granulometric and physicochemical compositions, have been determined. The influence of the height of the layer and the procedure of backfilling the chamber space in the liquid phase on the formation of the necessary pressure for the opening of a microcrack was studied. The priority of backfilling the exogenous macrocracks with significant gaps and those between tectonic blocks with mixtures has been analytically substantiated and confirmed by experimental methods of research in the mine.

Underground coal gasification is an alternative method for mining coal from thin and ultra-thin seams, which enables conversion of solid fossil fuels into combustible gases at the site of coal occurrence. At the same time, in the case when the coal seam thickness is critically small for the effective course of thermochemical reactions, it is necessary to intensify the gasification process. This paper studies one of the possible methods to intensify the process of underground coal gasification due to the influence of magnetic fields on the injected blast supplied into the gas generator gasification channel. Research tests conducted on a bench setup confirm the effectiveness of injected blast activation in a magnetic field by creating magnetic field inhomogeneity by placing permanent magnets and a discrete solid magnetized phase in a special device. For the first time, the dependence of changing growth of carbon participation during the solid fuel gasification process on changing magnetic field strength in the range of 0-600 E has been determined. It has been proven that the injected blast magnetization can significantly intensify the underground gasification process by increasing the carbon participation share in the fuel, which may be of practical importance for increasing the yield of combustible components.

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.

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.