Processing biomass

Abstract

Methods are provided for reducing one or more dimensions of individual pieces of biomass; treating biomass, such as size-reduced biomass; changing a molecular structure of a biomass material; and, optionally, subjecting the biomass to a primary process to form a product. The methods include processing biomass materials using a screw extrusion process, and treating the biomass material with a screw extrusion process in size-reduction and treating steps.

What is claimed is: 
     
         1 . A method of processing biomass materials using a screw extrusion process, the method comprising:
 conveying one or more biomass materials through a screw extrusion process comprising one or more screw extruders; and   exposing the one or more biomass materials to electron beam radiation from a plurality of scanning electron beam emitters while conveying the one or more biomass materials through one of the one or more screw extruders, the scanning electron beam emitters each effecting a desired dose of electron beam radiation at a dose rate of 1 Mrad per second to about 10 Mrad per second.   
     
     
         2 . The method of  claim 1 , further comprising applying compression and shear forces via a plurality of interpenetrate helicoidal surfaces within one of the one or more screw extruders, the forces effective to reduce one or more dimensions of individual pieces of biomass material. 
     
     
         3 . The method of  claim 1 , wherein the dose of electron beam radiation received by the biomass material depends, at least in part, on the speed of the screw extruder. 
     
     
         4 . The method of  claim 1 , wherein conveying comprises selectively advancing the biomass material through a plurality of apertures after a desired effect of the screw extrusion process has been attained. 
     
     
         5 . The method of  claim 3 , wherein the desired effect comprises a change in one or more of: level of recalcitrance, average molecular weight, average crystallinity, surface area, average fiber length, average length-to-diameter ratio, average BET surface area, bulk density, degree of polymerization, porosity, degree of branching, degree of grafting, domain size of the biomass material, and molecular make-up of the biomass material. 
     
     
         6 . The method of  claim 1 , wherein the screw extrusion process comprises controlling the temperature of the biomass material within one or more zones by means of controlled heating or cooling. 
     
     
         7 . The method of  claim 1 , wherein the screw extrusion process comprises one or more of the following elements: a mixing element, a pulverizing element, and a kneading element. 
     
     
         8 . The method of  claim 1 , wherein the electron beam radiation provides a dose of about 10 Mrad and about 150 Mrad. 
     
     
         9 . The method of  claim 1 , wherein the electron beam radiation is applied at a power of between 100 kW to 500 kW. 
     
     
         10 . A method of processing biomass materials using a screw extrusion process, the method comprising:
 conveying one or more biomass materials through a screw extrusion process comprising one or more screw extruders; and   exposing the one or more biomass materials to ionizing radiation while conveying the one or more biomass materials through one of the one or more screw extruders at a dose rate of 1 Mrad per second to about 10 Mrad per second.   
     
     
         11 . The method of  claim 10 , further comprising applying compression and shear forces via a plurality of interpenetrate helicoidal surfaces within one of the one or more screw extruders, the forces effective to reduce one or more dimensions of individual pieces of biomass material. 
     
     
         12 . The method of  claim 10 , wherein the dose of ionizing radiation received by the biomass material depends, at least in part, on the speed of the screw extruder. 
     
     
         13 . The method of  claim 10 , wherein conveying comprises selectively advancing the biomass material through a plurality of apertures after a desired effect of the screw extrusion process has been attained. 
     
     
         14 . The method of  claim 13 , wherein the desired effect comprises a change in one or more of: level of recalcitrance, average molecular weight, average crystallinity, surface area, average fiber length, average length-to-diameter ratio, average BET surface area, bulk density, degree of polymerization, porosity, degree of branching, degree of grafting, domain size of the biomass material, and molecular make-up of the biomass material. 
     
     
         15 . The method of  claim 10 , wherein the screw extrusion process comprises controlling the temperature of the biomass material within one or more zones by means of controlled heating or cooling. 
     
     
         16 . The method of  claim 10 , wherein the screw extrusion process comprises one or more of the following elements: a mixing element, a pulverizing element, and a kneading element. 
     
     
         17 . The method of  claim 10 , wherein the ionizing radiation provides a dose of about 10 Mrad and about 150 Mrad. 
     
     
         18 . The method of  claim 10 , wherein the ionizing radiation is applied at a power of between 100 kW to 500 kW. 
     
     
         19 . The method of  claim 10 , wherein the ionizing radiation comprises an ion beam. 
     
     
         20 . The method of  claim 10 , wherein the ionizing radiation comprises one or more species of ions selected to cause chain scission reactions. 
     
     
         21 . The method of  claim 10 , wherein the ionizing radiation comprises one or more species of ions selected to cause ring-opening chain scission reactions. 
     
     
         22 . The method of  claim 10 , wherein the ionizing radiation comprises one or more species of ions selected to enhance oxidation of the one or more biomass materials. 
     
     
         23 . The method of  claim 10 , wherein the ionizing radiation comprises one or more species of positively charged ions. 
     
     
         24 . The method of  claim 10 , wherein the ionizing radiation comprises one or more species of negatively charged ions. 
     
     
         25 . The method of  claim 10 , wherein the ionizing radiation comprises: carbon ions and oxygen ions, carbon ions and protons, nitrogen ions and protons, or iron ions and protons. 
     
     
         26 . The method of  claim 10 , wherein the ionizing radiation comprises one or more of: carbon ions, nitrogen ions, oxygen ions, silicon ions, phosphorus ions, sodium ions, calcium ions, and iron ions. 
     
     
         27 . The method of  claim 10 , wherein the ionizing radiation comprises one or more species of metal ions. 
     
     
         28 . The method of  claim 10 , wherein the ionizing radiation comprises one or more species of noble gas ions. 
     
     
         29 . The method of  claim 10 , wherein the one or more species of noble gas ions comprises one or more of: helium ions, neon ions, and argon ions.