Performed tests showed that at 298 K hard coals sorb relatively small amounts of hydrogen. Those amounts depend on carbon and oxygen content in tested coals. The most considerable amounts of hydrogen are sorbed by coals characterized by strong surface hydrophobicity and high content of aliphatic hydrocarbons. The hydrophilic nature of coal surface does not lead to higher sorption of hydrogen. It was found that the change in amount of sorbed hydrogen is closely related to the moisture. For high moisture coal a significant decrease in hydrogen sorption is observed. Also tests on hydrogen desorption on hard coals were carried out using method of lowering hydrogen pressure above the sorbent. Obtained results showed that tested coals desorb various amounts of hydrogen. Process of sorption is reversible only for some coals, while for the others the desorption isotherm partially lies beneath the sorption isotherm, which indicates that in addition to hydrogen some other chemical substances are emitted from coal.
has been carried out of the AGH project No. 11.11.210.244 and within the framework of research task No. 3 under the title Elaboration of the Mesaurement Principles and Research of Mine Air Parameters for the Assessment of Methane and Fire Hazard in Underground Mining Hard Coal executed within the framework of strategic research project under the title Improvement of Work Safety in Mines (Contract No.
The aim of this study was to examine the effect of the temperature of surrounding rocks on enthalpy and temperature of air flowing along several model mine workings. Long workings surrounded by non--coal rocks as well longwall gates surrounded by coal were taken into consideration. Computer-aided simulation methods were used during the study. At greater depths the amount of moisture transferred into a mine working from the rock mass is two orders of magnitude smaller than the moisture that comes from external (technological) sources, mainly from coal extraction-related processes, therefore in the equation describing temperature changes only the terms representing the flux of heat from rocks were included. The model workings, for calculation purposes, were divided into sections, 50 m in length each. For each of the sections temperature of its ribs and temperature and stream of enthalpy of air flowing along it were calculated with the use of the finite differences method. For workings surrounded by non-coal rocks two variant calculations were carried out, namely with or without technological sources of heat. For coal surrounded workings (longwall gates) a new method for determination of heat from coal oxidation was developed, based on the findings by Cygankiewicz J. (2012aCygankiewicz J. ( , 2012b. Using the results of a study by J.J. Drzewiecki and Smolka (1994), the effects of rock mass fracturing on transfer of heat into the air stream flowing along a working were taken into account. Keywords: safety, ventilation, air-conditioning, heat and mass transferBadano wpływ temperatury pierwotnej skał na strumień entalpii oraz temperaturę powietrza w wyrobisku korytarzowym o długości 2000 m. Rozpatrywano wyrobiska kamienne oraz chodniki podścia-nowe. W badaniach zastosowano metodę symulacji komputerowych. Na dużych głębokościach wilgoć przenoszona z górotworu do wyrobiska jest dwa rzędy wielkości mniejsza od wilgoci pochodzącej od procesów technologicznych. W związku z powyższym w równaniu opisującym zmiany temperatury w masywie skalnym uwzględniono tylko człon reprezentujący ruch ciepła w skałach. Badane wyrobisko podzielono na odcinki o długości 50 m. Korzystając z metody różnic skończonych dla każdego z odcinków wyznaczono temperaturę ociosu, a następnie temperaturę i strumień entalpii powietrza. W odniesieniu do wyrobisk kamiennych rozważania przeprowadzono dla wariantu z technologicznymi źródłami ciepła oraz Cygankiewicza (2012aCygankiewicza ( , 2012b. Korzystając z wyników badań J. Drzewieckiego i J. Smołki (1994), uwzględniono wpływ spękań górotworu na przenoszenie ciepła do powietrza w wyrobisku.Słowa kluczowe: bezpieczeństwo, aerologia, klimatyzacja, przepływ ciepła i masy
Type, amount and composition of gases which form in rocks and coals during a metamorphism process depend on a number of factors in particular genetic type of original matter, way and conditions of its gathering, temperature, pressure and geological time. Sorption tests were done by the volumetric method, with the use of adsorption micro-burettes. A major advantage of the measurement set-up is that the surplus amounts of adsorbate can be used in experiments, which is of particular importance when handling sorbents with heterogeneous structure, such as hard coals. Sorbates used in the test program were the vapours of hexane, hex-1-ene, heptane, hept-1-ene, octane and benzene. Measurement results seem to corroborate the hypothesis that sorption of polar substance vapours is chiefly a surface process. Polarity of hard coals, mostly associated with the presence of reactive oxygen groups (nitrogen and sulphuric groups), largely affects the sorption of polar substances and in a most characteristic manner controls the sorption of apolar ones. In the case of the latter, sorption is induced by the action of the dispersive interaction force between the coal surface and the sorbate's polar molecules. The pattern of sorption isotherms indicates that the presence of dual bond affects the sorbent-sorbate interactions and hence the sorption capacity of investigated coals.
In this paper results of investigations of sorption of hard coal samples collected from the extracted coal seams of Polish coal mines are presented. As sorbate propane was used. Examinations were carried out in the temperature of 298 K by means of volumetric assessment with the use of apparatus ASAP 2010 of Micromeritics. On the basis of conducted examinations it has been found out that the amount of sorbed propane depend on a type of coal, its metamorphism grade, content of oxygen element, moisture and porosity of these coals. The greatest amounts of propane are sorbed by low carbonized, high-porosity coals of high content of oxygen and moisture. Sorption of relatively high amounts of propane by these coals (ca. 10 cm 3 /g) is a result of the influence of polar surface of coals with molecules of propane and good availability of internal microporous structure of these coals for molecules of examined sorbate. Medium and high carbonized coals sorb insignificant amounts of propane. These coals have compact structure and non-polar character of their surface, their internal porous structure is to a minor degree available for propane molecules in conditions of carried out research. Sorption of propane in this case, takes place mainly in surface pores and on the surface of coals. Moreover, measurements of desorption isotherms of propane showing irreversible character of sorption were made. Desorption isotherms do not come together with sorption isotherms forming open hysteresis loop. Amounts of non-desorbing propane remaining in the coal depend on the type of examined coal.Keywords: hard coal, propane, sorption, desorption W pracy przedstawiono wyniki badań sorpcji próbek węgli kamiennych pobranych z eksploatowanych pokładów węglowych polskich kopalń. Jako sorbat zastosowano propan. Badania przeprowadzono w temperaturze 298 K metodą objętościową z wykorzystaniem aparatu ASAP 2010 firmy Micromeritics. Na podstawie przeprowadzonych badań stwierdzono, że ilości sorbowanego propanu są zależne od rodzaju węgla, jego stopnia metamorfizmu, zawartości pierwiastka tlenu, wilgoci i porowatości tych węgli. Największe ilości propanu sorbują węgle niskouwęglone, wysokoporowate o dużej zawartości tlenu i wilgoci. /g) jest wynikiem oddziaływania polarnej powierzchni węgli z cząsteczkami propanu oraz dobrej dostępności wewnętrznej mikroporowatej struktury tych węgli dla cząsteczek badanego sorbatu. Węgle średnio i wysokouwęglone sorbują niewielkie ilości propanu. Węgle te mają zwartą budowę oraz niepolarny charakter powierzchni, ich wewnętrzna struktura porowata jest w niewielkim stopniu dostępna dla cząsteczek propanu w warunkach przeprowadzanych badań. Sorpcja propanu w tym przypadku zachodzi głównie w powierzchniowych porach i na powierzchni węgli. Przeprowadzono również pomiary izoterm desorpcji propanu wykazując nieodwracalny charakter sorpcji. Izotermy desorpcji nie zbiegają się z izotermami sorpcji tworząc otwartą pętlę histerezy. Pozostające w węglu ilości nie desorbującego się propanu są zależne od rodzaju badanego węgla.Słow...
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