Szczegóły publikacji
Opis bibliograficzny
Studies on ${CO_{2}}$ sorption on hard coal in the near-critical area with regard to the aspect of sequestration — Badania sorpcji ${CO_{2}}$ na węglu kamiennym w obszarze przykrytycznym w aspekcie sekwestracji / Paweł BARAN, Michał BROŚ, Adam NODZEŃSKI // Archives of Mining Sciences = Archiwum Górnictwa ; ISSN 0860-7001 . — 2010 — vol. 55 iss. 1, s. 59–68. — Bibliogr. s. 66–67
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Dane bibliometryczne
| ID BaDAP | 51580 |
|---|---|
| Data dodania do BaDAP | 2010-05-05 |
| Rok publikacji | 2010 |
| Typ publikacji | artykuł w czasopiśmie |
| Otwarty dostęp |  |
| Czasopismo/seria | Archives of Mining Sciences = Archiwum Górnictwa |
Abstract
Recently more and more emphasis has been laid on reducing the emission of carbon dioxide. Attempts are undertaken to reduce the emission of this gas through the works on the low-emission technologies of fuel combustion. Another way to lower the emission of CO2 is to capture the gas and deposit it in deep geological layers. One of the options of geological sequestration, next already applied the EOR method (Nagy and Olajossy, 2008; Núñez- López et al., 2008) is pumping CO2 into deep, fully exploited or unexploited beds of hard coal. The issue of carbon dioxide sorption studies is presently handled with regard to the possibility of sequestrating this gas in deep geological structures. Considering the depth of the storage centre and assuming that hydrostatic pressure gradient at the level of 10 MPa/km and the geothermal gradient at the level of 30 K/km (Tarkowski, 2005), it is expected that the stored carbon dioxide will appear in the supercritical state. The supercritical phase shows the properties of a gas with high density, close to the density of fluid substances which changes depending on the pressure and temperature in the range from 200 up to 900 kg/m3 (Fig. 1) (Holloway and Savage, 1996). The definition of supercritical adsorption which is presented in the work is ambiguous in the literature, due to various approaches regarding the definition of the supercritical phase (fluid). One of the approaches says that the fluid is supercritical when both the temperature and the pressure reach values above the critical point. However, adsorption in supercritical conditions (supercritical adsorption) is commonly interpreted to be a process which takes place in a temperature above the critical temperature (Toth, 2002). The work presents experimental results of studies on CO2 sorption on high rank coal obtained from the Lower Silesian Coal Basin. The table 1 provides selected results of the chemical, technological and density analysis (Nodzeński, 2000). The measurements have been carried out with the use of original volume apparatus designed to examine the sorption of gases in the supercritical area. The developed apparatus also makes it possible to measure the sorption of mixtures (e.g. CO2 + CH4). After the state of balance is established, it is also possible to source the free (unsorbed) phase disturbing the sorption balance. The principle of sorption measurement at increased pressures by the volume method consists in decompressing a gas of a known pressure and volume from the batching space to an ampoule containing a sorbent. Knowing the dead volume of the apparatus and the volume of the batcher, it is possible to calculate the absorbed quantity by means of the gas laws. The presented calculation procedure takes into account the CO2 deviations from the properties of the ideal gas. The gas molar volume for a given pressure and temperature has been calculated by means of two equations: the Beattie-Bridgeman Equation of State and the Span-Wagner multi-parameter equation (Michałowski and Wańkowicz, 1993; Span and Wagner, 1996). The figure 3 shows that up to the pressures of about 2.5 MPa, the molar volumes calculated with the use of both equations of state are convergent. In case of higher pressures, the calculated values show differences. Following the sorption isotherms obtained at a subcritical temperature, the thermal equation of sorption (Czepirski and Jagiełło, 1989) was used to generate an isotherm in 323 K which was then confronted with an isotherm obtained through an experiment. An unsatisfactory correspondence was found between the isotherm generated by means of the thermal sorption equation and the isotherm obtain in course of the experiment (Fig. 4). The gas capacity values obtained as a result of prediction are overestimated by about 5 dm3/kg which testifies to a significant change of properties of the arrangement after the critical temperature is exceeded.
