Viscosities of coal—water—methanol mixtures

A plot of viscosity measurements for coal—water—methanol mixtures vs. percentage methanol in the liquid indicates that the viscosities of both coal—water and coal—alcohol slurries are increased by the addition of the second liquid. The shape of the slurry viscosity curve is very similar, on a greatly exaggerated scale, to the plot of viscosity versus percentage methanol for the pure liquid mixtures. Measurements were made as a part of a test program involving coal—water-methanol fuels. Initial mixtures were 60 wt% Pittsburgh seam coal in liquids composed of varying proportions of water and methanol. Slurries of Montana Rosebud and Texas Lignite coals in water—methanol mixtures also displayed viscosity maxima, but at different fractions of methanol. There was no viscosity peak for 40, 50 or 55% petroleum coke slurries. Slurries of ground glass in water-methanol mixtures were evaluated for comparison and a viscosity maximum was observed, although the peak occurred at a methanol concentration somewhat lower than it occurs in the pure liquid mixture.