Methods and devices for processing lignocellulosic biomass using mechanical pretreatment to enhance feedstock hydration properties

A method of processing lignocellulosic biomass by autohydrolysis, the method comprising the steps of:

• providing lignocellulosic biomass feedstock comprising straw and/or grass,
• subjecting the lignocellulosic biomass feedstock to mechanical compression using a mechanical or hydraulic piston compression system prior to hydrothermal pretreatment to produce a briquette, wherein the briquette has a diameter of greater than 25 mm, wherein a fiber structure of the lignocellulosic biomass feedstock is substantially preserved,
• subjecting said lignocellulosic biomass feedstock to hydrothermal pretreatment at a water content during pretreatment, of at least 40% for a residence time of between 1 and 120 minutes at a temperature between 160° and 220° C. wherein water is added as steam condensate in the case of pre-wetted feedstocks or for dry feed-stocks by homogeneous rapid absorption of water content added at reactor temperature and pressure, in batch-mode in an unagitated pressure reactor in such manner that agitation of the feedstock during pretreatment is avoided either by mechanical means or by explosive release of pretreated material to lower pressure,
• removing pretreated lignocellulosic biomass feedstock from the pressure reactor, and
• sequentially repeating the batch-mode pretreatment so as to maintain a semi-continuous process, wherein a quantity of biomass is used to fill the pressure reactor in which the biomass is pretreated and then removed without additional loading and unloading of the reactor during the pretreatment of said quantity of biomass;
• wherein the lignocellulosic biomass feedstock has a rapid hydration swelling factor of at least 7.