Coal-water slurry and method for its preparation

Abstract

A pipeline pumpable coal-water slurry having a novel combination of coal particles and carrier water is prepared by a method wherein the particle sizes and their distribution are controlled in accordance with a particle size distribution formula which is especially beneficial for providing a novel coal compact with a minimum amount of void space between particles and a maximum amount of particle surface area with an advantageous amount of colloidal sized particles present. These features combine to enhance the dispersing effects generated by electrolytes and/or dispersing agents selected and added to the coal compact and/or slurry to provide a near maximum zeta potential to the particles in the slurry and to provide low viscosity to the resulting yield pseudoplastic coal-water slurry. Brookfield viscosities obtained, e.g. 1000 cps, or less, at 60 rpm with 75 wt. % coal, dry basis, make the coal-water slurry especially advantageous for transport by pipeline over long distances. The coal-water slurry can be provided at a high coal content so that the slurry can be burned directly without need for dewatering at its destination.

Dependencies are inferred from the claim text.