Gasification of Carbonaceous Material

Abstract

A process for gasifying a carbonaceous particulate feedstock includes dividing the carbonaceous particulate feedstock into at least two feedstock fractions, each feedstock fraction including particulate material within a predetermined particle size range so that there are at least a smaller particle size feedstock and a larger particle size feedstock. The smaller particle size feedstock is fed to at least one gasifier and the larger particle size feedstock is fed to at least one other gasifier.

1 - 13 . (canceled)  
     
     
         14 . A process for gasifying a carbonaceous particulate feedstock, the process including 
 dividing the carbonaceous particulate feedstock into at least two feedstock fractions, each feedstock fraction including particulate material within a predetermined particle size range so that there are at least a smaller particle size feedstock and a larger particle size feedstock; and    feeding the smaller particle size feedstock to at least one fixed bed dry bottom gasifier and the larger particle size feedstock to at least one other fixed bed dry bottom gasifier.    
     
     
         15 . The process as claimed in  claim 14 , in which each gasifier receives only one of the feedstocks and none of the gasifiers receive more than one of the feedstocks.  
     
     
         16 . The process as claimed in  claim 14 , in which the smaller particle size feedstock has a particle size distribution with an upper limit which is at least about 5 times its lower limit.  
     
     
         17 . The process as claimed in  claim 16 , in which the upper limit is at least 6 times the lower limit.  
     
     
         18 . The process as claimed in  claim 17 , in which the upper limit is at least 7 times the lower limit.  
     
     
         19 . The process as claimed in  claim 14 , in which the larger particle size feedstock has a particle size distribution with an upper limit which is at least about 1.5 times its lower limit.  
     
     
         20 . The process as claimed in  claim 19 , in which the upper limit is at least twice the lower limit.  
     
     
         21 . The process as claimed in  claim 20 , in which the upper limit is at least 2.5 times the lower limit.  
     
     
         22 . The process as claimed in  claim 14 , in which the smaller particle size feedstock is fed to a gasifier or gasifiers at a mass flow rate at least about twice the mass flow rate at which the larger particle size feedstock is fed to a gasifier or gasifiers.  
     
     
         23 . The process as claimed in  claim 14 , in which the larger particle size feedstock includes more non-carbonaceous material on a percentage by mass basis than the smaller particle size feedstock, the process including subjecting at least the larger particle size feedstock to a beneficiation or an upgrading stage.  
     
     
         24 . The process as claimed in  claim 23 , in which the upgrading stage includes a size reduction step in which the average particle size of the particulate carbonaceous material of the larger particle size feedstock is reduced.  
     
     
         25 . The process as claimed in  claim 14 , in which the gasifier or gasifiers fed with the smaller particle size feedstock is/are operated with an oxygen to pure gas volumetric ratio of between 0.19 and 0.21 and coal as feedstock and produce(s) a raw gas comprising between 27 and 28 mole % C0 2  at a pure gas yield of at least 1660 Nm 3 /ton of dry ash free coal.  
     
     
         26 . The process as claimed in  claim 14 , in which the smaller particle size feedstock has a particle size distribution with a lower limit larger than 4 mm.