Sunday, April 29, 2007

Reaction kinetics of lignin liquefaction

Bo Zhang, Marc Von Keitz, and Kenneth Valentas. BioTechnology Institute, University of Minnesota, 1479 Gortner Avenue, Suite 140, St. Paul, MN 55108

Lignins derived from abundant and renewable resources are nontoxic and extremely versatile in performance, qualities that have made them increasingly important in many industrial applications.  We have shown recently that liquefaction of lignin extracted from aspen wood resulted in a 78% yield of bio-crude oil [1].  In this study, the direct conversion of four types of lignin, kraft pine lignin provided by MeadWestvaco Corporation, kraft lignin obtained from Sigma-Aldrich, lignin extracted from mixed southern hardwoods, and organosolv lignin, was studied using the following treatment variables: heating rate, cooling rate, reaction temperature, reaction time, and catalysts.  Comparisons were made of the reaction products obtained under the different treatment conditions.  The major compounds from lignin liquefaction were identified and quantified by GC-MS.  A kinetic model of lignin liquefaction was proposed to predict the yield of liquid products.  The dependence of the calculated kinetic coefficients on temperature was established using Arrhenius-type equations.

[1] Zhang, B., von Keitz, M. and Valentas, K. (2007). Hydrothermal Conversion of Wood: Reaction Kinetics and Process Development, The American Chemical Society 233rd National Meeting.