Apparatus and method for upgrading coal

Abstract

A method of upgrading coal is disclosed, the method comprising: subjecting the coal to a hydrothermal dewatering process at a temperature and a pressure above ambient conditions to produce dewatered coal; removing ash tailings from the dewatered coal to produced reduced ash dewatered coal; and producing a coal water slurry with the reduced ash dewatered coal. An apparatus for upgrading coal is also disclosed, the apparatus comprising: a hydrothermal dewatering reactor connected to receive coal and output dewatered coal; an ash separator connected to receive dewatered coal from the hydrothermal dewatering reactor and output reduced ash dewatered coal; a slurrifier connected to receive reduced ash dewatered coal from the ash separator and output a coal water slurry.

1 . A method of upgrading coal, the method comprising:
 subjecting the coal to a hydrothermal dewatering process at a temperature and a pressure above ambient conditions to produce dewatered coal;   removing ash tailings from the dewatered coal to produce reduced ash dewatered coal; and   producing a coal water slurry with the reduced ash dewatered coal.   
     
     
         2 . The method of  claim 1  further comprising subjecting the coal water slurry to gasification to produce syngas. 
     
     
         3 . The method of  claim 2  in which subjecting the coal water slurry to gasification further comprises reacting the coal water slurry with oxygen in a gasifier and cooling the produced syngas in a quench cooler. 
     
     
         4 . The method of  claim 1  in which the coal comprises low rank coal. 
     
     
         5 . The method of  claim 4  in which low rank coal comprises lignite. 
     
     
         6 . The method of  claim 5  in which the lignite is Inner Mongolian coal or Boundary Dam coal. 
     
     
         7 . The method of  claim 1  in which removing ash tailings is carried out in one or more flotation cells. 
     
     
         8 . The method of  claim 1  in which the coal is subjected to hydrothermal dewatering at between 200 and 300 degrees Celsius. 
     
     
         9 . The method of  claim 1  in which the coal is subjected to hydrothermal dewatering at between 2.0 and 8.0 MPa. 
     
     
         10 . The method of  claim 1  in which the coal subjected to hydrothermal dewatering has an average particle size of less than 0.5 mm. 
     
     
         11 . The method of  claim 1  in which the coal is agitated during hydrothermal dewatering to reduce the average particle size to 0.5 mm or less. 
     
     
         12 . The method of  claim 1  further comprising grinding the coal to an average particle size of 0.5 mm or less. 
     
     
         13 . The method of  claim 1  further comprising removing gas from the hydrothermal dewatering process and supplying the removed gas to a heat exchanger. 
     
     
         14 . The method of  claim 1  further comprising supplying water produced at one or more stages of the method into one or more stages of the method that use water. 
     
     
         15 . An apparatus for upgrading coal, the apparatus comprising:
 a hydrothermal dewatering reactor connected to receive coal and output dewatered coal;   an ash separator connected to receive dewatered coal from the hydrothermal dewatering reactor and output reduced ash dewatered coal;   a slurrifier connected to receive reduced ash dewatered coal from the ash separator and output a coal water slurry.   
     
     
         16 . The apparatus of  claim 15  further comprising a gasifier connected to receive coal water slurry from the slurrifier and output syngas. 
     
     
         17 . The apparatus of  claim 16  further comprising a quench cooler connected to receive syngas from the gasifier. 
     
     
         18 . The apparatus of  claim 15  in which the ash separator further comprises one or more flotation cells. 
     
     
         19 . The apparatus of  claim 15  further comprising a heat exchanger connected to receive gas produced in the hydrothermal dewatering reactor. 
     
     
         20 . The apparatus of  claim 15  further comprising a grinder connected between the hydrothermal dewatering reactor and the ash separator. 
     
     
         21 . The apparatus of  claim 15  in which the hydrothermal dewatering reactor is configured to grind coal by agitation. 
     
     
         22 . The apparatus of  claim 15  further comprising a reservoir connected to recycle water produced by the apparatus back into the apparatus.