Yield Point and Stability of Highly Loaded Coal-Water Mixture (CWM)

Abstract

For commercial-scale production of highly loaded CWM (coal-water mixture), it is necessary to predict its future stability immediately after production. However, the previously reported method of evalua ting the stability is unable to predict it because it takes a long time to obtain results. We have found a quantitative correlation between the yield point and stability of CWM, from the rheological characteristics of CWM, and the following conclusions have been attained.1) The Saxon Vale coal CWM showing a higher yield point was found to remain stable for a longer period.2) With an increase in the agitating energy applied to CWM, its yield point is improved and the stability period is lengthened.3) With an increase in the amount of a dispersant added, the yield point is lowered to a certain stationary value. This suggests that an optimum dispersant amount exists for stabilization of CWM.4) The smaller t he coal particle size is, the higher the yield point is. Likewise, with an increase in the coal concentration, the yield point is raised.5) A more-immature coal having larger (H) and (0) values shows lower yield point, or is poorer in CWM stability.