US Patent 11821047 High pressure zone formation for pretreatment

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