Pretreating cellulosic biomass

Abstract

The present invention pertains to methods for pretreatment of cellulosic biomass for bioconversion into ethanol and other biofuels and wood-based chemicals, recycling of newsprint and other paper products, microfibrillation of cellulose for use as an additive in the food and cosmetic industries, manufacturing improved hardboard, and producing and improved “super” pulp while reducing chemical usage and spent liquor generation. In particular, the instant invention employs supercritical, critical or near critical fluids with and without polar cosolvents [critical fluid, SuperFluids or SFS] for the pretreatment of cellulosic biomass.

1 . A method of removing aromatic compounds from a cellulosic biomass having one or more aromatic compounds comprising the steps of combining a cellulosic biomass with a critical, near critical or supercritical fluid with or without a polar cosolvent; explosively decompressing said biomass to form a aromatic fluid and a disrupted biomass. 
     
     
         2 . The method of  claim 1  wherein said aromatic fluid is received in a recycling loop. 
     
     
         3 . The method of  claim 2  wherein said recycling loop removes said aromatic compound from said aromatic fluid to form a non-critical fluid and one or more aromatic compounds and directs said non-critical fluid to means for changing at least one of the group selected from temperature, pressure or constituents to make said non-critical fluid a near critical, critical or supercritical fluid with or without a polar cosolvent. 
     
     
         4 . The method of  claim 1  wherein said biomass is further processed with enzymes. 
     
     
         5 . The method of  claim 1  wherein said biomass is used as a feed component. 
     
     
         6 . The method of  claim 1  wherein said biomass is used as pulp. 
     
     
         7 . The method of  claim 1  wherein said biomass is converted to ethanol. 
     
     
         8 . The method of  claim 1  wherein said step of explosively decompressing said fluidized biomass comprised a 75 to 99% reduction in pressure over a period of time not exceeding 180 seconds. 
     
     
         9 . The method of  claim 8  wherein said reduction in pressure is in a period of time not exceeding sixty seconds. 
     
     
         10 . The method of  claim 9  wherein said reduction in pressure is in a period of time not exceeding one second. 
     
     
         11 . The method of  claim 1  wherein said step of combining the cellulosic biomass with a critical, near critical or supercritical fluid with or without a polar cosolvent takes place over a period of time of one minute to two hours. 
     
     
         12 . A device for removing one or more aromatic compounds from a cellulosic biomass comprising:
 A vessel having a chamber, a port, means for introducing a near critical, critical or supercritical fluid, means for explosively decompressing said near critical, critical or supercritical fluid with or without a polar cosolvent to form a aromatic fluid; said chamber for containing a cellulosic biomass having one or more aromatic compounds, said port having an open position for receiving a said cellulosic biomass having one or more aromatic compounds and a closed position in which said chamber is substantially closed, said means for introducing a near critical, critical or super critical fluid with or without a polar cosolvent in communication with at least one near critical, critical or supercritical fluid with or without a polar cosolvent, said means for explosively decompressing said critical, near critical or supercritical fluid capable of rapidly reducing pressure in said chamber;   A recycling loop in fluid communication with said means for explosively decompressing said near critical, critical or supercritical fluid with or without a polar cosolvent to receive said aromatic fluid, said recycling loop separating said aromatic compounds from said aromatic fluid to form a non-critical fluid and one or more aromatic compounds;   Critical fluid means for changing at least one of the group selected from temperature, pressure or constituents to make said non-critical fluid a near critical, critical or supercritical fluid with or without a polar cosolvent, said critical fluid means in communication with said recycling loop to receive said non-critical fluid and in communication with said means for introducing a near critical, critical or super critical fluid, said vessel receiving a biomass having one or more aromatic compounds in said chamber and forming a fluidized biomass with said near critical, critical or supercritical fluid with or without a polar cosolvent, and upon explosive decompression a aromatic fluid and a disrupted biomass, said aromatic fluid received in said recycling loop to form a aromatic compound and a non-critical fluid, said non-critical fluid received by said critical fluid means and processed to make a critical, near critical or supercritical fluid with or without a polar cosolvent to be received in said chamber.