Method for Preparing a Slurry of Pulverized Solid Material in Liquid or Supercritical Carbon Dioxide

Abstract

Method for making a slurry of a pulverized solid in liquid or supercritical carbon dioxide. The method includes making a water-pulverized solid slurry at ambient pressure and pressurizing the water-pulverized solid slurry to a high pressure. The pressurized water-pulverized solid slurry is mixed in a pressurized chamber with liquid or supercritical CO 2 to form a CO 2 ˜pulverized solid slurry.

What is claimed is: 
     
         1 . Method for making a slurry of a pulverized solid in liquid or supercritical carbon dioxide comprising:
 making a water-pulverized solid slurry at ambient pressure;   press arising the water-polverized solid slurry; and   mixing the pressurized water-pulverized solid slurry with liquid or supercritical CO 2  in a pressurized chamber, to form a CO 2 -pulverized solid slurry,   
     
     
         2 . The method of  claim 1  further including vaporizing excess CO 2  from the CO-pulverized solid slurry to concentrate the CO 2 -pulverized solid slurry. 
     
     
         3 . The method of  claim 1  wherein the water-pulverized solid slurry is pressurized in the range of 60-80 bar 
     
     
         4 . The method of  claim 2  wherein CO 2  is vaporized to provide a 80% loading. 
     
     
         5 . The method of  claim 1  further including a slurry skimming to remove substantially all of the CO 2  from the CO 2 -pulverized solid slurry. 
     
     
         6 . The method of  claim 5  wherein the slurry skimming step involves low-grade heat addition. 
     
     
         7 . The method of  claim 5  wherein the slurry skimming step involves a pressure reduction.