Considerations referring to coal swelling accompanying the sorption of gases and water

Author: R. Skawiński

This paper contains a concise history of investigations concerning the coal swelling accompanying the sorption of gases and water.

The external swelling of coal, (i.e. the enlargement of sample sizes) and the internal swelling (observed as the permeability decrease during the flow of sorbing fluids) are also discussed.

The coal swelling occurs in coal substance.

The molecular structure of coal substance and the main mechanism of its swelling as the result of interaction of sorbed molecules with the complexes of coal macromolecules, is consisely presented in the paper.

The direct measurement of the coal swelling is very difficult or almost impossible.

The coal swelling may be evaluated as changes of permeability accompanying the flow of sorbing fluids.

The paper contains considerations on the realationship between the variations of permeability and swelling of coal.

The considerations are based on the mechanism of coal swelling and certain assumptions concerning the changes of pore space.