Lignin extraction--reassessment of the severity factor with respect to hydroxide concentration.

Steam processes have often been associated with a severity factor, correlating the cooking temperature, time and catalyst used in the process. Although equations for treatments with and without acid catalyst have been suggested, there is so far no simple equation allowing a precise estimation of the amount of lignin extracted from lignocellulosic biomass. In this work, a new version of the severity factor equation is proposed.