Rapid pretreatment

Abstract

Disclosed herein are methods, systems, and compositions for the pretreatment of biomass within seconds with low inhibitor formation. The pretreatment process is used to convert biomass to a fuel or other useful chemicals by subjecting the feedstock to a rapid retention time under pressure and temperature and/or chemical reactant. The system includes a continuously-operating valve discharge apparatus to discharge pretreated feedstock while maintaining uniform pressure on the pretreatment system.

What is claimed is: 
     
         1 . An industrial scale method for pretreating at least one dry ton of biomass per day, the method comprising:
 a. feeding the biomass at a rate of at least one dry metric ton (MT) of biomass per day into an extrusion system comprising a barrel defining an inner chamber comprising a feeder zone and a reaction zone; and   b. treating the biomass at an elevated temperature and pressure within the reaction zone for less than about 20 seconds, thereby producing a pretreated biomass composition comprising a liquid fraction comprising monosaccharides and solid particles comprising cellulose.   
     
     
         2 . The method of  claim 1 , wherein the extrusion system further comprises one or more rotatable screws configured to move the biomass through the extrusion system from the feeder zone and through the reaction zone. 
     
     
         3 . The method of  claim 2 , wherein the one or more rotatable screws comprise one or more sections that are configured to form one or more plugs from the biomass to separate the inner chamber into two or more zones, including the feeder zone and the reaction zone. 
     
     
         4 . The method of  claim 3 , comprising two rotatable screws. 
     
     
         5 . The method of  claim 1 , wherein the rate of biomass feeding is at least about 75 dry MT/day. 
     
     
         6 . The method of  claim 1 , wherein the method comprises continuously producing the pretreated biomass composition. The method of  claim 1 , wherein the method further comprises continuously releasing the pretreated biomass composition from the extrusion system. 
     
     
         8 . The method of  claim 1 , further comprising adding a liquid to the biomass prior to the reaction zone. 
     
     
         9 . The method of  claim 1 , wherein the biomass is treated for about 5 to 15 seconds in the reaction zone. 
     
     
         10 . The method of  claim 1 , wherein the elevated temperature is about 150-300° C. 
     
     
         11 . The method of  claim 1 , wherein the elevated pressure is about 300-500 PSI. 
     
     
         12 . The method of  claim 1 , further comprising adding a chemical agent to the biomass in the reaction zone. 
     
     
         13 . The method of  claim 12 , wherein the chemical agent comprises an acid, a base, or a combination thereof. 
     
     
         14 . The method of  claim 12 , wherein the chemical agent comprises sulfuric acid. 
     
     
         15 . The method of  claim 1 , wherein the liquid fraction comprises C5 monosaccharides in at least a 70% yield compared to the theoretical maximum based on the biomass. 
     
     
         16 . The method of  claim 1 , wherein the liquid fraction comprises C6 monosaccharides less than a 35% yield compared to the theoretical maximum based on the biomass. 
     
     
         17 . The method of  claim 1 , wherein less than 15 kg of formic acid is produced per MT of dry biomass. 
     
     
         18 . The method of  claim 1 , wherein less than 60 kg of acetic acid is produced per MT of dry biomass. 
     
     
         19 . The method of  claim 1 , wherein less than 5 kg of hydroxymethyl furfural (HMF) is produced per MT of dry biomass. 
     
     
         20 . The method of  claim 1 , wherein less than 7.5 kg of furfural is produced per MT of dry biomass.