Abstract: The present disclosure generally relates to a method for controlled pretreatment of lignocellulosic biomass. The method comprises the steps of: Pretreating (S10) a lignocellulosic biomass material in a pretreatment arrangement, the pretreating comprising impregnating (S10A) the lignocellulosic biomass with an SO2 feed in an impregnation vessel of the pretreatment arrangement; collecting (S20) a number of process parameters of the pretreatment, which process parameters include at least a feed parameter related to the total amount of lignocellulosic biomass input to the pretreatment arrangement, and a dry matter parameter related to the dry matter content of lignocellulosic biomass input to the pretreatment arrangement; and adjusting (S30) the SO2 feed in response to the process parameters.

Abstract: The present disclosure generally relates to a pretreatment arrangement (100) for pretreatment of lignocellulosic biomass comprising a reactor vessel (101) extending along a longitudinal center line (102) and having an upstream inlet (103) for receiving biomass and a downstream outlet (104) for discharging biomass. The pretreatment arrangement (100) further comprising a scraping device (108) configured to scrape the interior walls (111) of the reactor vessel (101) and prevent the formation and build-up of deposits.

Abstract: The present invention relates to a method for pretreating a softwood starting material comprising the following steps: a) pretreating the softwood starting material in a pretreatment process to form a slurry; b) measuring the concentration of glucose and the concentration of mannose in the slurry formed in step a); c) calculating a ratio glucose:mannose from the concentrations measured in step b) d) comparing the ratio calculated in step c) to a reference value and if the ratio calculated in step c) differs from the reference value, controlling at least one process parameter of the pretreatment process in response to the difference.