The Flows of Nitrogen and Water through Coal Briquettes of Various Porosity

• Autorzy: Żółcińska J. , Dyrga L.
• Języki publikacji: EN

Abstrakty

EN

The present paper aim is the determination of the relationship between the pore structure of coal samples and their permeability in relation to nitrogen and water. The variability of the pore structure was obtained by compressing of selected grain fractions under different compressing forces. For the analysis of the pore structure in the samples, the porosity and the reference permeability for the nitrogen flow have been selected. The coal studied represented the "Miechowice" (Bytom Region) and "Zofiówka" (Jastrzębie Region) mines. For adequate coal samples obtained from the "Zofiówka" and "Miechowice" mines the similar experimental qualitative images of the permeability changes in the flow of nitrogen and water have been observed. The quantitative differences in the magnitude of coal swelling correspond with the results of densimetric and porosimetric investigations of the coal structure. Within the range of pressures applied by the authors (20-80 MPa), a distinct decrease (two orders of magnitude) of permeability for nitrogen bas been observed. The porosity of investigated samples has changed only twofold. It results from pore restructuring. The overall pore volume changes only slightly. The dimensions and topological form of the pores are subject to variations: the grains crack and new internal fissures are formed within them, whereas the void spaces among grains are reduced. The interaction between water and the coal substance leads to internal coal swelling. The process is manifested by lowering of permeability of the sample. The quantitative effect of swelling and the decrease of water permeability depends on the general packing of grains in the sample i.e. on the conditions of its preparation. Coal swelling is mare rapid and water penetrates deeper coal zones for coal from the "Miechowice" mine (higher nitrogen permeability and porosity) than for the coal from the "Zofiówka". After 5 days of the water flow through the samples, the permeability for the "Miechowice" coal was reduced 25 times, whereas for the "Zofiówka" coal - only 6 times.

Słowa kluczowe

EN

coal briquettes; porosity; nitrogen and water flow; permeability; swelling

• Wydawca: Centrum Upowszechniania Nauki PAN
• Czasopismo: Bulletin of the Polish Academy of Sciences. Earth Sciences
• Rocznik: 2002
• Tom: Vol. 50, nr 2
• Strony: 99--111
• Opis fizyczny: Bibliogr. 21 poz.

Twórcy

autor

Żółcińska J.

autor

Dyrga L.

• Strata Mechanics Research Institute, Polish Academy of Sciences, Kraków, Poland