Fuel slurry preparation system and method

Abstract

A system includes a grinder, a storage unit, and an organic compound production unit. The grinder is configured to produce a fuel slurry from a solid fuel, a liquid, and an organic compound that is miscible with the liquid. The storage unit is configured to supply the organic compound to the grinder. The organic compound production unit is configured to receive a portion of syngas generated by a gasifier to generate the organic compound for supply to the storage unit.

1 . A system, comprising:
 a grinder configured to produce a fuel slurry from a solid fuel, a liquid, and an organic compound that is miscible with the liquid;   a storage unit configured to supply the organic compound to the grinder; and   an organic compound production unit configured to receive a portion of syngas generated by a gasifier to generate the organic compound for supply to the storage unit.   
     
     
         2 . The system of  claim 1 , wherein the storage unit is configured to supply the organic compound to the grinder during startup of the gasifier. 
     
     
         3 . The system of  claim 1 , wherein the storage unit is configured to stop supplying the organic compound to the grinder during shutdown of the gasifier. 
     
     
         4 . The system of  claim 3 , wherein the organic compound production unit is configured to supply the organic compound to the grinder during operation of the gasifier, and to the storage unit during shutdown of the gasifier. 
     
     
         5 . The system of  claim 3 , wherein the organic compound production unit is configured to supply the organic compound to the storage unit during both operation and shutdown of the gasifier. 
     
     
         6 . The system of  claim 1 , comprising the gasifier configured to receive the fuel slurry and to generate the syngas from the fuel slurry. 
     
     
         7 . The system of  claim 1 , wherein the organic compound production unit is configured to receive a portion of syngas generated from another gasifier to generate the organic compound for supply to the storage unit. 
     
     
         8 . The system of  claim 1 , wherein the organic compound comprises methanol, ethanol, or a mixture of organic compounds having varying purity levels. 
     
     
         9 . The system of  claim 1 , comprising a controller configured to control an amount of the organic compound that is mixed with the solid fuel and the liquid in order to maintain a desired pore penetration of the solid fuel or viscosity of the fuel slurry in response to a monitored solids concentration of the fuel slurry. 
     
     
         10 . The system of  claim 1 , comprising a vessel disposed between the grinder and the gasifier, wherein the vessel is configured to store the fuel slurry under a desired pressure. 
     
     
         11 . A method, comprising:
 providing an organic compound from a storage unit to a grinder;   mixing the organic compound with a solid fuel and a liquid to generate a fuel slurry via the grinder;   generating an additional amount of the organic compound from a syngas, wherein the syngas is generated from the fuel slurry via a gasifier; and   providing the additional amount of the organic compound to the grinder for mixing the fuel slurry or to the storage unit.   
     
     
         12 . The method of  claim 11 , comprising:
 starting the gasifier; and   receiving and gasifying the fuel slurry to generate the syngas.   
     
     
         13 . The method of  claim 11 , comprising providing the additional organic compound to the storage unit and not to the grinder when the gasifier is not operating. 
     
     
         14 . The method of  claim 13 , comprising providing the additional amount of the organic compound to the grinder and not to the storage unit during gasification. 
     
     
         15 . The method of  claim 13 , comprising providing the additional amount of the organic compound to both the grinder and the storage unit during gasification. 
     
     
         16 . The method of  claim 11 , comprising supplying the organic compound to the storage unit from an outside source. 
     
     
         17 . The method of  claim 11 , comprising:
 mixing the organic compound with the solid fuel via the grinder to generate an organic compound/solids mixture; and   mixing the organic compound/solids mixture with the liquid via the grinder to generate the fuel slurry.   
     
     
         18 . A system, comprising:
 a controller configured to:
 monitor a solids concentration of a fuel slurry comprising a mixture of a solid fuel, an organic compound, and a liquid; and 
 control an amount of the organic compound supplied to the mixture based on the monitored solids concentration; 
 wherein the organic compound is at least partially recycled from a syngas generated from the fuel slurry via a gasifier. 
   
     
     
         19 . The system of  claim 18 , wherein the controller is configured to:
 control an amount of the organic compound provided from a storage unit to generate the mixture; and   control an additional amount of the organic compound provided from an organic compound production unit to generate the mixture, wherein the organic compound production unit is configured to produce the additional amount of the organic compound from a portion of the generated syngas.   
     
     
         20 . The system of  claim 19 , wherein the controller is configured to stop a flow of the organic compound from the storage unit to generate the mixture, and to refill the storage unit with the additional amount of the organic compound from the organic compound production unit when the gasifier is not operating.