Coal water slurry and methods for making the coal water slurry

Abstract

A coal water slurry comprises smaller and larger coal particles. The smaller coal particles are in a range of from about 20 wt % to about 90 wt % of the coal in the coal water slurry and comprise a mean particle size smaller than 25 μm. The larger coal particles are in a range of from about 10 wt % to about 80 wt % of the coal in the coal water slurry and comprise a mean particle size in a range of from 50 μm to 200 μm.

1 . A coal water slurry, comprising:
 smaller coal particles in a range of from about 20 wt % to about 90 wt % of the coal in the coal water slurry and having a mean particle size smaller than 26 μm; and   larger coal particles in a range of from about 10 wt % to about 80 wt % of the coal in the coal water slurry and having a mean particle size in a range of from 50 μm to 200 μm.   
     
     
         2 . The coal water slurry of  claim 1 , wherein the smaller and larger coal particles comprise low rank coal. 
     
     
         3 . The coal water slurry of  claim 1 , wherein the coal water slurry comprises the smaller coal particles in a range of from about 40 wt % to about 90 wt % and the larger coal particles in a range of from about 10 wt % to about 60 wt % of the coal in the coal water slurry, respectively. 
     
     
         4 . The coal water slurry of  claim 1 , wherein the coal water slurry comprises the smaller coal particles in a range of from about 50 wt % to about 75 wt % and the larger coal particles in a range of from about 25 wt % to about 50 wt % of the coal in the coal water slurry, respectively. 
     
     
         5 . The coal water slurry of  claim 1 , wherein the coal water slurry comprises the smaller coal particles in a range of from about 30 wt % to about 50 wt % and the larger coal particles in a range of from about 50 wt % to about 70 wt % of the coal in the coal water slurry, respectively. 
     
     
         6 . The coal water slurry of  claim 1 , wherein the larger coal particles have the mean particle size in a range of from about 50 μm to about 140 μm. 
     
     
         7 . The coal water slurry of  claim 1 , wherein the large coal particles have a mean particle size in a range of from 90 μm to 140 μm. 
     
     
         8 . The coal water slurry of  claim 1 , wherein the large coal particles have a mean particle size in a range of from 100 μm to 140 μm. 
     
     
         9 . The coal water slurry of  claim 1 , wherein the large coal particles have a mean particle size in a range of from 140 μm to 200 μm. 
     
     
         10 . The coal water slurry of  claim 1 , wherein the smaller coal particles have the mean particle size less than about 25 μm. 
     
     
         11 . The coal water slurry of  claim 1 , wherein the smaller coal particles have the mean particle size less than about 15 μm. 
     
     
         12 . The coal water slurry of  claim 1 , wherein the smaller coal particles have the mean particle size less than about 10 μm. 
     
     
         13 . The coal water slurry of  claim 1 , wherein the smaller coal particles have the mean particle size in a range of from about 10 μm to about 15 μm. 
     
     
         14 . A method for making a coal water slurry, comprising:
 milling smaller coal particles in a range of from about 20 wt % to about 90 wt % of the coal in the coal water slurry and comprising a mean particle size smaller than 26 μm;   milling larger coal particles in a range of from about 10 wt % to about 80 wt % of the coal in the coal water slurry and having a mean particle size in a range of from 50 μm to 200 μm; and   mixing the smaller coal particles, the larger coal particles, and water.   
     
     
         15 . The method for making the coal water slurry of  claim 14 , further comprising filtering the coal water slurry after mixing of the smaller coal particles and the larger coal particles. 
     
     
         16 . The method for making the coal water slurry of  claim 14 , wherein milling comprises using a coarse mill for producing the larger coal particles and a fine mill for producing the smaller coal particles. 
     
     
         17 . The method for making the coal water slurry of  claim 16 , wherein using the coarse mill comprises wet milling and using the fine mill comprises dry milling. 
     
     
         18 . The method for making the coal water slurry of  claim 17 , wherein mixing comprises introducing the smaller coal particles and the larger coal particles respectively into a mixing vessel. 
     
     
         19 . The method for making the coal water slurry of  claim 17 , wherein mixing comprises introducing the smaller coal particles into the coarse mill for mixing. 
     
     
         20 . The method for making the coal water slurry of  claim 16 , wherein using the coarse mill comprises wet milling and using the fine mill comprises wet milling. 
     
     
         21 . The method for making the coal water slurry of  claim 20 , further comprising introducing a portion of a coarse coal from the coarse mill into a mixing vessel and another portion of the coarse coal into the fine mill to produce the smaller coal particles for introduction into the mixing vessel. 
     
     
         22 . The method for making the coal water slurry of  claim 14 , wherein the large coal particles have a mean particle size in a range of from about 100 μm to about 140 μm. 
     
     
         23 . The method for making the coal water slurry of  claim 14 , wherein the mean particle size of the smaller coal particles is less than about 25 um. 
     
     
         24 . The method for making the coal water slurry of  claim 14 , wherein the smaller coal particles are in a range of from about 50 wt % to about 75 wt % and the larger coal particles are in a range of from about 25 wt % to about 50 wt % of the coal in the coal water slurry, respectively.