Abstract
Rheological properties of coal slurries in No. 2 oil and ethanol blends containing various amounts of water have been investigated in detail. Water is observed to increase the viscosity of the slurries. The slurries exhibited appreciable yield stress in the presence of water. The final subsided volume increased sharply and a decrease in critical solids concentration was observed up to 10% of water, above which these effects leveled off. In the case of low coal concentration slurries, the viscosity and the yield stress increased with increasing amounts of water and a critical shear rate was observed. Depending upon the concentration of water, the slurries behaved as dilatant, Newtonian or pseudoplastic below the critical shear rate, in the lower shear rate region. In the higher shear rate region, they exhibited pseudoplastic behavior. The slurries containing higher coal loading were pseudoplastic at all water concentrations, and viscosity along with yield stress exhibited a maximum around 10% of water. The rheological parameters have been analysed using the power law and Bingham plastic models. The effect of water on the rheological characteristics has been explained on the basis of coal particle bridging by water, which is supported by the measured subsidence volumes and critical solids concentration.
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Adiga, K.C., Pithapurwala, Y.K., Shah, D.O. et al. Rheology of coal slurries in no. 2 oil and ethanol blends: Effect of water. Rheol Acta 22, 402–409 (1983). https://doi.org/10.1007/BF01333771
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DOI: https://doi.org/10.1007/BF01333771