Study on proportioning of similar materials for overburden rock in underground gasification model experiment

In order to provide an accurate theoretical basis for the underground gasification model test of coal, the similar materials ratio of underground gasification’s overburden rock was studied by orthogonal experiment according to the similarity theory. The results show: the fifth group material ratio meets the model test requirements, the mass ratio of sand, cement and gypsum is 6:1:1, and the compressive strength is 1.36MPa; the material strength is most sensitive to sand as compared to cement and gypsum; the compressive strength decreases as the aggregate–binder ratio increases. When the aggregate–binder ratio remains the same, the compressive strength decreases as the cement-gypsum ratio increases; the compressive strength-elastic modulus curve of the specimen increases linearly and conforms to the sandstone fitting curve in the coal-bearing strata; the failure mode of similar materials is mainly shear failure.

Is the Złoczew lignite deposit geologically suitable for the first underground gasification installation in Poland?

The present study focuses on alternative methods of exploiting lignite in comparison to conventional opencast mining and combustion in power plants for the generation of electricity. In Poland, opencast lignite pits cover large areas, creating social and environmental conflicts. In order to stabilise the production level of electricity and reduce the negative effects of opencast mining, alternative ways of exploiting lignite are suggested, one of these being underground gasification in situ. The Złoczew lignite deposit, which will most likely be exploited in the near future, provides an opportunity to discuss the unconventional method of underground coal gasification (UCG). On the basis of technological and geological criteria that have been established to determine the suitability of Polish lignite for underground gasification, resources to be used this way have been estimated. Through gasification, over 15 million tonnes of lignite can be utilised, which is about 2.5 per cent of resources of the Złoczew deposit intended for opencast mining. With this in mind, we suggest to take action by starting a pilot installation, to be followed by a commercial one for underground gasification after completion of superficial mining. Naturally, any future application of this method will be preceded by assessment of geological conditions at the Złoczew opencast pit.

Conditions of Suitability of Coal Seams for Underground Coal Gasification

Results of evaluating the suitability of certain sections of Western Donbas coal seams, based predominately on properties of coal material, for their further experimental development by means of underground gasification method are represented. Criteria to evaluate both expediency of underground gasification and specific conditions of that process are substantiated basing upon the methodology developed at the National Mining University (Dnipro, Ukraine) together with representatives from National University of Saint Augustine (Arequipa, Peru). The methodology has been industrially approved with the confirmation of its efficiency while developing technical documentation for underground gasification projects: “Project of experimental section of Pidzemgaz station of Pavlogradvuhillia association”, “Feasibility study of the expediency of the construction of Pidzemgaz station” FS 3858-PZ”, Synelnykovo deposit; “Project on experimental underground gas generator”, Monastyryshche deposit, FS of experimental module of UCG station of Solenovske coal-mining area, Donbas. Also, they contain the researches, which were conducted within the project GP – 489, financed by Ministry of Education and Science of Ukraine.

TEMPERATUREREGIME OF COAL BED BY UNDERGROUND COAL GASIFICATION IN THE FILTRATION CHANNEL

A mathematical model of the temperature regime of a coal bed during underground coal gasification in a filtration channel for new geotechnologies of Tula State University is developed. It is proposed to describe the unsteady temperature field of the coal seam with the one-dimensional heat conduction equation with the heat sink that depends on the temperature of the coal bed. The equation is solved for semi-infinite space. The results of computational experiments have shown that the temperature front from the fire face moves deep into the coal bed. Consequently, in the process of underground gasification, pre-heating of coal in the gasified block and thermal preparation take place. Quite quickly, after the formation of stable combustion of coal in the fire face, a stationary temperature profile is established.

Analysis of Risk Factors for Underground Coal Gasification

The purpose of this article is to determine the environmental impacts of underground gasification on the population and to analyze the risk of underground coal gasification (UCG) activities using selected risk assessment methods. Coal gas is a regular part of coal deposits and its extraction also allows the use of coal deposits that cannot be extracted by traditional methods. These technologies bring both positive and negative aspects. The paper points out the risk analysis, hazard identification and assessment during the operation of UCG technology using a risk graph and a risk matrix. Identified risks to workers that cannot be reduced should be taken into consideration and appropriate safeguard should be used. For each risk, it is necessary to inform employees about regular education and training. From worldwide experience with this technology, it is possible to analyze risks in Slovakia. Actual gasification produces polluting gases such as carbon dioxide, carbon monoxide, hydrogen sulphide, hydrogen sulphide, nitrogen oxides, tar and ash, and creates a risk that may occur on and under the surface of the site depending on the geological and hydrogeological structure of the deposits. Possible measures to mitigate the adverse effects are proposed for the implementation of this technology. Coal is still one of the main domestic primary energy sources. Currently, only 5 out of 19 deposits in the Slovak Republic are used. Underground gasification could increase the use of Slovak coal and brown coal deposits.

Characteristic of Possible Obtained Products during the well Underground Coal Gasification

This article is a summarizing of the results of the author's team on the establishment of technological parameters of underground gasification. It provides a justification of the final chemical and energy products that can be obtained as a result of complex physical and chemical transformations of coal. The thermodynamic processes of formation of the gasification source when changing the composition of the blast furnace mixture and the modes of its application to the georeactor are considered. Moreover, the change in the stress-strain state of rocks depending on the composition of the lateral rocks is taken into account. To better ensure the results are consistent with the well-known principles of thermodynamics and phase formation under the influence of the temperature field and the main chemical reactions occurring in complex gasification processes are presented. The main phase transitions in the georeactor are given for the maximum reception of different energy gases. Particular attention is given to the formation of an appropriate relationship between hydrogen and carbon monoxide, which form a synthesis gas. The Anderson-Schultz-Flory reaction is used to determine the maximum CO concentration in the outlet mixture. In general, the system for determining the material and thermal balance is proposed. These approaches were checked both for working out the coal reserves and for utilization of the mining waste products. Results of this investigation were included to the Roman Dychkovskyi thesis of the scientific degree of the Doctor of the Technique Sciences “Scientific Principles of Technologies Combination for Coal Mining in Weakly Metamorphoses Rockmass”. Also, this results were partially presented on international scientific and practical conferences “Forum of Miners” from different years. They contain the researches, which were conducted within the project GP – 489, financed by Ministry of Education and Science of Ukraine.

COMPLEX DEVELOPING COAL AND TECHNOGENIC DEPOSITS OF MOSCOW COAL BASIN

Conceptual principals of high-technological and power efficient producing nanomaterials and rare-earth metals for providing row materials import substitution and technological independence on enterprises in central Region of Russia are formulated. It’s shown that the problem can be solved on basis innovation technologies of integrated developing coal and anthropogenic deposits of Moscow Coal Basin. The solution of the problem consists of complex approach to studying and creating geotechnologies of deep processing coals and industrial wastes with using brown coal underground gasification.