PROCESS FOR PRODUCING A BIO-PRODUCT

It is disclosed a process for producing a bio-product from a ligno-cellulosic biomass, wherein the ligno-cellulosic biomass, a gas and steam are introduced in a pressurized reactor operated in a continuous manner at conditions to have a vapor head space. In the pressurized reactor, the vapor head space is maintained at a vapor head space temperature and at a pressure which is at least 1 bar greater than a pure steam equilibrium pressure at the vapor head space temperature. The ligno-cellulosic biomass is then refined by rapidly releasing the pressure while discharging the ligno-cellulosic biomass from the pressurized reactor assembly to create a pre-treated ligno-cellulosic biomass, which is then hydrolyzed and converted to the bio-product. Preferably, at least a portion of the gas is air entrapped in the ligno-cellulosic biomass and it is introduced into the pressurized reactor as part of the ligno-cellulosic biomass. In a preferred embodiment, the lignocellulosic biomass is subjected to a soaking step and an aeration step prior to being introduced into the pressurized reactor, without any xylans separation step.