| Abstract: | A non‐conventional pulping process based on the delignification of cardoon (Cynara cardunculus L) in ethanol–water mixtures has been studied to evaluate its pulping potential and to establish the optimum pulping conditions for this lignocellulosic material. The variables analyzed were the concentration of ethanol in the cooking liquor, the pulping time and temperature. Variable optimization was performed by a central composite design. High viscosity, low kappa number and acceptable screened yield were used as pulp quality criteria to optimize cooking conditions. Pulps having low kappa numbers and viscosities greater than 900 cm3/g?1 were obtained. The total pulp yield was low compared with wood pulping due to the high contents of extractives and ash in cardoon. The amount of rejects in the pulp is of importance, especially for pulps with a high kappa number. The most suitable pulping conditions were 188 °C, 135 min and 50% (w/w) ethanol concentration. In these conditions the kappa number of the pulp was around 26, the pulp viscosity greater than 1100 cm3 g?1 and a screened pulp yield of about 31% was obtained. Copyright © 2005 Society of Chemical Industry |
