APPLICATION OF FACTORIAL DESIGN TO THE MODELING OF ORGANOSOLV DELIGNIFICATION OF MISCANTHUS-SINENSIS (ELEPHANT GRASS) WITH PHENOL AND DILUTE-ACID SOLUTIONS

The Battelle-Geneva method of fractionation of lignocellulosic materia ls was applied to the biomass of an annual cane-like plant, Miscanthus sinensis (elephant grass). A factorial second-order composite design was used to quantify the influences of three variables of the process (independent variables), (1) time, in the interval: 0.37-2.35 h; (2) p henol concentration, in the interval: 41.6-58.4% by weight; (3) hydroc hloric acid charge, in the interval: 0.0098-0.0602 g HCl/g dry Miscant hus, on five dependent variables: (I) pulp yield, (2) residual lignin in pulps, (3) dissolved reducing sugars, (4) total polysaccharides in pulp, and (5) selectivity of the process, measured as the ratio pulp y ield/residual lignin in pulp. Experimental results were fitted to seco nd-order lineal-models by means of a multiple regression method Expres sions obtained showed R-2 values varying between 0.80 and 0.99, obtain ing fittings from acceptable to good depending on each case. The model predicted a maximum in the selectivity for the following values of in dependent variables: time, 1 h 48 min: phenol concentration 53.2%; aci d charge, 0.0394g HCl/g dry Miscanthus. With regard to the other respo nses variations shown were, in general, logical according to the incre ase or decrease of the independent variables. (C) 1997 Elsevier Scienc e Ltd.