Role of Maceral Composition on the Formulation of Concentrated Coal-Water Slurry Using a Natural Surfactant

Abstract

The stabilization of coal-water slurry(CWS) depends on both inherent properties of coal and the external factors like solution pH, presence of additives, temperature, modulation of coal surface by ultrasonic radiation or microwave treatment etc. The rank and chemical composition i.e. mineral and maceral composition of coal are very much important in the formulation of CWSand some other applications of coal. The present investigation involves the formulation and stabilization of CWS using four varieties of non-coking Indian coalsstabilized by a natural surfactant saponin as dispersant. Proximate and ultimate analyses of coal were investigated to get first hand information on the compositions of the coals. The reflectance and X-ray diffraction studies indicated the amount of macerals and minerals present in the coals under investigation. The rheological parameters of CWS were analyzed by coal-loading, dispersant percentage, solution pH and temperature. The CWS formed from all coals followed the Bingham plastic model and behaved as a Non-Newtonian fluid in the presence of saponin. The static stability of CWS prepared from Talcher coals was however, found to be superior to that prepared fromIb river valley coals. The extent of the maceral and mineral percentage was assigned to be the primary reason for the variation in the slurry behaviour