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| Titel |
Study of sorption and swelling on block coals |
| VerfasserIn |
Shijie Qu, Guoqing Chen, Jianli Yang, Wenzhong Shen, Yunmei Li, Hongxian Niu, Andreas Busch |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250084364
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| Zusammenfassung |
| Reducing CO2 emission into atmosphere is very important for the mitigation of global
climate change. Many processes have been proposed for this purpose, including CO2
sequestration in un-minable coalbeds and enhance coalbed methane production
(CO2-ECBM). Several theoretical studies and worldwide demonstration sites have illustrated
the potential of the process.Most of these projects experienced permeability reduction of the
coalbed with time, leading to operational difficulties because of the loss of injectability. The
permeability reduction is generally considered to be caused by the coal swelling that is
induced by gas sorption, because it can narrow or close the cleat of the coalbed. As a result,
the migration of injected CO2 in coal pore or cleat becomes more difficult. Therefore,
sorption and swelling characterizations are important issues for forecasting the performance
of aimed coalbed.
In this work, CO2/CH4sorption and swelling isotherms of two Chinese block coals (QS
and YQ) were measured simultaneously under different temperature and pressure conditions.
It was found that the swelling ratio of coal block by CO2 sorption increased with the increase
of the gas sorption amount until it approached to a value of ~3 mmol-gas/g-coal
and decreased slightly afterwards for both coals; while the swelling ratio of coal
block by CH4 sorption increased with the increase of the gas sorption amount in the
entire test region for both coals. By correlating the gas sorption amount and the
corresponding swelling ratio, it was found that the swelling ratio of coal block is
independent of temperature and coal type when the gas sorption amount is less than
~2mmol/g-coal. The differential profile of the swelling ratio with respect to sorption amount
is appeared with a maximum value at ~1 mmol/g-coal for CH4 and at ~1.8 mmol/g-coal
for CO2. Based on the theories related to gas sorption and solid surface energy, a
mathematical model which correlates sorption and swelling behavior was proposed. |
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