Method for treating lignocellulosic biomass by impregnation

A process for the continuous treatment of a lignocellulosic biomass for the production of sugary liquors, said process comprising:

• a) impregnating the biomass using an impregnation liquor with a pH of between 0.1 and 7, by placing said biomass in contact with said impregnation liquor,
• b) separating the impregnated biomass obtained in a) so as to produce a wet biomass with a solids content of at least 15% by weight, and a separated liquor,
• c) pretreating the wet biomass obtained in b) to produce a pretreated biomass, in the course of which one or more liquid streams are withdrawn,
• d) analyzing (i) the composition of the separated liquor obtained from b), (ii) the composition of one or more of the liquid streams withdrawn during c) the pretreating of the wet biomass, or (iii) the composition of the separated liquor obtained from b) and one or more of the liquid streams withdrawn during the pretreating of the wet biomass in c), and
• e) adjusting the composition of the impregnation liquor used in a) so as to keep constant the acidic power, corresponding to the amount of H+ ions present, of (i) said separated liquor obtained from b), (ii) said one or more liquid streams withdrawn during the pretreating of the wet biomass in c), or (iii) both, throughout the process,
• wherein the impregnation liquor comprises at least one acid, and optionally water, and
• wherein adjusting of the composition of the impregnation liquor is performed by adding water, acid, or both to said impregnation liquor used in a), so as to keep constant, throughout the process, the acidic power of the separated liquor obtained from b) or the acidic power of the one or more liquid streams withdrawn during pretreating of the wet biomass in c), or both.