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Frontiers of Chemical Science and Engineering

Front Chem Sci Eng    2012, Vol. 6 Issue (1) : 94-103     DOI: 10.1007/s11705-011-1172-2
Modeling of coal swelling induced by water vapor adsorption
Zhejun PAN()
CSIRO Earth Science and Resource Engineering, Clayton 3168, Australia
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Gas adsorption-induced coal swelling is a well-know phenomenon. Coal swelling or shrinkage by adsorption or desorption of water vapor has not been well understood but has significant implications on gas drainage process for underground coal mining and for primary and enhanced coalbed methane production. Decreased matrix moisture content leads to coal shrinkage and thus the change of cleat porosity and permeability under reservoir conditions. Unlike gas adsorption in coal which usually forms a single layer of adsorbed molecules, water vapor adsorption in the coal micropores forms multilayer of adsorbed molecules. In this work, a model has been developed to describe the coal swelling strain with respect to the amount of moisture intake by the coal matrix. The model extended an energy balance approach for gas adsorption-induced coal swelling to water vapor adsorption-induced coal swelling, assuming that only the first layer of adsorbed molecules of the multilayer adsorption changes the surface energy, which thus causes coal to swell. The model is applied to describe the experimental swelling strain data measured on an Australian coal. The results show good agreement between the model and the experimental data.

Keywords multilayer adsorption      vapour pressure      coal shrinkage      relative humidity      permeability     
Corresponding Authors: PAN Zhejun,   
Issue Date: 05 March 2012
 Cite this article:   
Zhejun PAN. Modeling of coal swelling induced by water vapor adsorption[J]. Front Chem Sci Eng, 2012, 6(1): 94-103.
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Zhejun PAN
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