Chemical and energetic characterization of species with a high‐biomass production : fractionation of their components

Abstract

In this work, we determined the properties of cellulose pulp and paper from six different lignocellulosic materials [Eucalyptus globulus, Arundo donax, Leucaena diversifolia, Paulownia fortunei, sunflower stalks and Chamaecytisus proliferus (tagasaste)], as well as the calorific value and chemical composition of their autohydrolysis liquor, with a view to assessing their potential for the obtainment of energy, sugars and other chemical products. An integral fractionation method based on autohydrolysis and organosolv delignification was used for this purpose. Leucaena diversifolia; P. fortunei; a Paulownia “trihybrid” consisting of elongata, tormentosa and fortunei varieties; sunflower stalks; and C. proliferus exhibited holocellulose, glucan, xylan and acetyl group contents similar to, or higher than, those of E. globulus, A. donax and various other lignocellulosic materials. The amounts of oligomers extracted from C. proliferus, P. fortunei, L. diversifolia and sunflower stalks at the highest temperatures studied exceeded those provided by eucalyptus. Sequential autohydroysis and organosolv delignification of L. diversifolia and C. proliferus provided cellulose pulp with an acceptable kappa number and paper sheets with good strength-related properties. Paulownia fortunei was the most interesting raw material among those tested; in fact, it provided ethanol pulp with a lignin content of 3.7 –15.3% and a kappa number of 40.5–74.1 after autohydrolysis at 190 ºC, and paper with a tensile index of 17.0–28.9 kN m/kg. These properties are similar to those of pulp and paper from eucalyptus wood. In addition, P. fortunei exhibited the highest calorific value among the studied materials (4683.8 cal/g).