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1

Deformation properties of sedimentary rocks in the process of underground coal gasification

Bukowska M., Sygała A.

Journal of Sustainable Mining

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2015

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Vol. 14, iss. 3

144--156

EN

The article presents results of research into changes in deformation properties of rocks, under influence of temperature, during the process of underground coal gasification. Samples of carboniferous sedimentary rocks (claystones and sandstones), collected in different areas of Upper Silesian Coal Basin (GZW), were heated at the temperature of between 100 and 1000-1200°C, and then subjected to uniaxial compression tests to obtain a full stress-strain curves of the samples and determine values of residual strain and Poisson's ratio. To compare the obtained values of deformation parameters of rocks, tested in dry-air state and after heating in a given range of temperature, normalised values of residual strain and Poisson's ratio were determined. Based on them, coefficient of influence of temperature on tested deformation parameters was determined. The obtained values of the coefficient can be applied in mining practice to forecast deformability of gangue during underground coal gasification, when in the direct surrounding of a georeactor there are claystones or sandstones. The obtained results were analysed based on classification of uniaxial compression strength of GZW gangue, which formed the basis for dividing claystones and sandstones into very low, low, medium and high uniaxial compression strength rocks. Based on the conducted tests it was concluded that the influence of uniaxial compression strength on the value of residual strain, unlike the influence of grain size of sandstones, is unambiguous within the range of changes in the parameter. Among claystones changes in the value of Poisson's ratio depending on their initial strength were observed. Sandstones of different grain size either increased or decreased the value of Poisson's ratio in comparison with the value determined at room temperature in dry-air conditions.

2

Material and Energy Flow Analysis (MEFA) of the unconventional method of electricity production based on underground coal gasification

Czaplicka-Kolarz K., Korol J., Ludwik-Pardała M., Ponikiewska K.

Journal of Sustainable Mining

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2014

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Vol. 13, iss. 3

41--47

EN

Purpose In this paper, the application of Umberto NXT LCA software to devise a Material and Energy Flow Analyses (MEFA) for the technology of producing electricity from gas extracted in the process of shaftless underground coal gasification is presented. The Material Flow Analyses of underground coal gasification includes a range of technology, through obtaining process gas and its purification, to electricity production, and, additionally, the capture of carbon dioxide. Methods To evaluate electricity production based on Underground Coal Gasification, Material and Energy Flow Analyses (MEFA) was used. Modeling material and energy flow helps a high level of efficiency or technology of a given process to be reached, through the effective use of resources and energy, or waste management. The applied software for modeling material flow enables, not only, the simulation of industrial processes, but also the simulation of any process with a material or energy flow, e.g. in agriculture. Results MEFA enabled the visualization of material and energy flow between individual unit processes of the technology of electricity production from UCG gas. An analysis of material and energy flow networks presented in the form of Sankey diagrams enabled the identification of unit processes with the biggest consumption of raw materials and energy, and the greatest amount of emissions to the environment. Practical implications Thanks to applying material and energy flow networks with Umberto software, it is possible to visualize the flow of materials and energy in an analyzed system (process/technology). The visualization can be presented in the form of an inventory list of input and output data, or in the form of a Sankey diagram. In the article, a Sankey diagram has been utilized. MEFA is first stage of the plan to conduct analyses using Umberto software. The analyses performed so far will be used in the following stages of the research to assess the environmental impact using the LCA (Life Cycle Assessment) technique, to analyze costs using the LCC (Life Cycle Cost) technique, and to analyze eco-efficiency. It is important to highlight the fact that this is the first attempt of material and energy flow analysis of electricity production from UCG gas. Originality/ value This is the first approach which contains a whole chain of electricity production from Underground Coal Gasification, including stages of gas cleaning, electricity production and the additional capture of carbon dioxide.

3

Unconventional technologies of coal seams extraction and processing

Vasyuchkov Yu, F.

Archives of Mining Sciences

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2008

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Vol. 53, no 2

215-220

EN

Methods of conventional technologies of coal mining provide natural fuel and coke basic industrial regions. World extraction of the coal has achieved 6 billons tones. In the conventional modern machines and mechanized complexes are used. The power industrial infrastructure has created. But the industry is characterized the shortages. These ones include high labour-intensive, high energy capacity, high social hazard and very much volurne of the empty rocks. Further development of coal industry in the conventional methods may be continued at the expense of the extensive ways. It is means the further development of the coal industry will require the increase of the shortages. Real alternative may be development of the unconventional the technologies in the coal industry as it is done in the ore production industry - for instance, many hundreds of thousands tones are extracted with unconventional microbiotechnological methods. In this report the new view on the development and principles of the unconventional technologies in the coal industry is done. The ways of the technologies use on coal fields are carries out. The conceptual scheme of the unconventional technologies is done.

PL

Technologie konwencjonalne stosowane w górnictwie węglowym dostarczają naturalny nośnik energii - również nośnik koksujący, do głównych ośrodków przemysłowych. Światowe wydobycie węgla osiąga ok. 6 mld ton rocznie. Nowoczesne górnictwo węgla jest wysoce zmechanizowane, wyposażone w zaawansowane kompleksy wydobywcze. Jednakże przemysł górniczy charakteryzuje się istotnymi, funkcjonalnymi wadami. Do nich można zaliczyć: duże nakłady pracy, wysoką energochłonność, wysoki stopień zagrożenia, wydobywanie wraz z węglem znacznej ilości skał płonych. Dalszy rozwój górnictwa, przy stosowaniu konwencjonalnych metod, może się odbywać przy znacznie wyższych kosztach, co oznacza powiększenie wad funkcjonalnych górnictwa. Alternatywą może być rozwój niekonwencjonalnych technologii w górnictwie węglowym, podobnie jak to się dzieje w górnictwie rud miedzi. Przykładem jest wydobywanie rud przy użyciu mikro biotechnologicznych metod. W artykule zarysowano zasady niektórych niekonwencjonalnych technologii (technologie podziemnego zgazowania węgla), które mogą być użyte w górnictwie węglowym. Zamieszczono schematy ideowe metod (rys. 1,2 i 3).