Abstract: Method for treating biomass, comprising compressing and dewatering (62) the biomass to a dry solid content of DS1% by weight; feeding (63) compressed biomass to a treatment vessel; adding (64) a treatment liquid to said treatment vessel; discharging (65) treated biomass; compressing and dewatering (66) discharged biomass to a dry solid content of DS2% by weight, and treating (68) the compressed and dewatered biomass in a hydrolysis reactor, wherein 1%<DS1?DS2<6%.

Abstract: A reactor arrangement for pre-hydrolysis of biomass material. The reactor arrangement comprises a reactor vessel arranged substantially horizontally, wherein the vessel comprises an inlet for receiving the biomass material arranged at an upper portion of the vessel. The inlet may be arranged at a first longitudinal end of the vessel. The vessel may furthermore comprise an outlet at a second longitudinal end of the vessel. The reactor arrangement further comprises a set of steam injection orifices arranged to inject or supply steam into the reactor vessel. The set of steam injection orifices comprises at least two orifices arranged below the inlet at a distance from each other. The at least two orifices may be arranged at a distance from each other in the lateral direction of the reactor vessel. Furthermore, a method for pre-hydrolysis treatment of biomass in a substantially horizontal reactor vessel is provided.

Abstract: A reactor arrangement for pre-hydrolysis of biomass material. The reactor arrangement comprises a reactor vessel arranged substantially horizontally, wherein the vessel comprises an inlet for receiving the biomass material arranged at an upper portion of the vessel. The inlet may be arranged at a first longitudinal end of the vessel. The vessel may furthermore comprise an outlet at a second longitudinal end of the vessel. The reactor arrangement further comprises a set of steam injection orifices arranged to inject or supply steam into the reactor vessel. The set of steam injection orifices comprises at least two orifices arranged below the inlet at a distance from each other. The at least two orifices may be arranged at a distance from each other in the lateral direction of the reactor vessel. Furthermore, a method for pre-hydrolysis treatment of biomass in a substantially horizontal reactor vessel is provided.