Rapid pretreatment

An industrial scale method for pretreating at least one dry ton of biomass per day in an extrusion system,

• wherein the extrusion system comprises
• (i) a barrel, wherein the barrel comprises a first inlet port near a first end of the barrel for receiving the biomass, an inner chamber comprising a feeder zone and a reaction zone, and a discharge valve opening at a second end of the barrel;
• and
• (ii) one or more rotatable screws within the inner chamber, wherein the one or more rotatable screws include sections configured to form one or more plugs,
• wherein the method comprises:
• (a) feeding the biomass at a rate of at least one dry metric ton (MT) of biomass per day into the feeder zone of the extrusion system through the first inlet port;
• (b) moving the biomass via the one or more rotatable screws through the barrel in a direction from the first end to the second end,
• (c) forming a plug from the biomass as the biomass is moved continuously through the extrusion system, wherein the plug separates the inner chamber comprising the biomass into the feeder zone and the reaction zone, wherein the feeder zone is upstream of the plug in the direction from the first end to the second end, and the reaction zone is downstream of the plug in the direction from the first end to the second end;
• (d) adding, through one or more sealable ports, to the biomass in the reaction zone pressurized steam and a chemical agent, and treating the biomass at a temperature of about 50-500° C. and a pressure of about 50-1000 PSI 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;
• and
• (e) continuously releasing the pretreated biomass composition from the extrusion system through the discharge valve opening.