Fig. 1
Mass balance-based process analysis of the two-step pretreatment process, combining STEX with HEX150/8 and HEX190/4, respectively. The data represent the composition of the liquid and solid fractions, as presented in Tables 1 and 2. Process streams were determined by measuring the weight and volume of all processing steps, including the wash fractions (WF) after STEX. The numbers marked with an asterisk were not measured but determined based on mass balances. Note: the rescaling of the masses and volumes to 1000 g of raw material led to minor over and underestimation of component masses, resulting in mass balances that are not fully closed (i.e., glucose in SFraw mat and SFSTEX)