Influence of dispersant on bound water content in coal–water slurry and its quantitative determination

A new method that determines the bound water content of coal–water slurry (CWS) was introduced in this article, and the experimental results proved the method has better feasibility and higher accuracy. In this study, the thermogravimetric analysis (TG) method was used to plot the drying-rate curve of CWS prepared from different ranks of coals, and the inflection points in the drying-rate curve were used to discriminate the volatilization cut-off points of free water and bound water in CWS. The results showed that the bound water contents of CWS prepared from different coals have much difference, and it is directly proportional to the O/C ratio, mineral content and average pore volume of the coals. The addition of dispersants decreased the bound water content of CWS sharply, and the higher rank of the coals, the more reduction level. The higher rank Yanzhou and Panjiang coals have the reduction level of 52.74% and 50.14%, respectively, while the lower rank Datong and Shenhua coal have the reduction level of 35.80% and 24.82%, respectively. Moreover, the provided method that measuring bound water content of CWS using TG has not been reported.