Patent ID: 8394235

Claim:
A process for pretreatment of a lignocellulosic biomass, comprising the steps of: exposing the lignocellulosic biomass to steam in an exposing step in a treatment vessel at a temperature of 190 to 220 degrees C. and an elevated pressure for an exposure time of 5 to 15 minutes; and purging volatile inhibitory compounds from the treatment vessel after having reached a pressure of 50 to 200 psig and for a duration of 20 to 600 seconds, and purging liquid inhibitory compounds after a delay of 60 seconds following pressurization, and for a duration of 380 seconds; and wherein the treatment vessel has a volatiles purge device including a valve that is selectively openable to permit flow at a controlled rate for a controlled duration of time, the volatiles purge device is located on the treatment vessel at a vertical position on the vessel above a level of the lignocellulosic biomass and the liquid compounds within the vessel, and the volatile compounds are removed through the volatiles purge device.