UBC Theses and Dissertations
Contact angle measurements on fine coal particles He, Ying Bin
This study investigates the techniques of contact angle measurement on fine coal particles. Two techniques, one direct and one indirect, have been investigated and modified. In the direct contact angle measurement technique, high pressure is employed to compress the coal powder into a pellet and the artificial surface of the pellet is employed in the contact angle measurements. The contact angle versus time and versus drop size on the pellet surface are examined. In addition, the pellet properties and factors affecting the pellet properties are also studied. A pellet surface model and a method for contact angle correction are proposed. In the indirect measurement, the contact angle is calculated from the penetration rate. The method is modified to employ high pressures to produce highly compact columns. The holding glass tube traditionally used for the column of powder is, therefore, no longer needed. The change in penetration behaviour of the liquid within such columns is investigated. The properties of the columns and the impact of the pressure applied in their formation on the rate of liquid penetration as well as other phenomena are studied. A contact angle calculation procedure is also proposed.
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