Organosolv ethanolamine pulping of olive wood: Influence of the process variables on the strength properties

Abstract: This paper reports on the influence of independent variables in the pulping of olive wood trimmings [viz. cooking temperature (165–195°C) and time (30–90min), ethanolamine concentration (5–15%), soda concentration (2.5–7.5%) and liquid/solid ratio (4–6)], on the yield and kappa number of the pulps and breaking length, burst index and tear index of the resulting paper sheets. By using a central composite factorial design, equations that relate each dependent variable to the different independent variables were obtained that reproduced the experimental results for the dependent variables with errors less than 15%. These equations could be used to find the suitable operations conditions, so that operating with not too high values of operating variables (with the consequent minor costs of capital and of operation) pulps could be obtained by acceptable strength properties. Optimizing pulp yield, the kappa number and the strength properties of the resulting paper sheets entails using rather different conditions in each case. Obtaining acceptably strong paper sheets while saving on immobilized capital through the use of smaller facilities and less chemical reagents entails using a medium soda concentration and low values of all other independent variables. In this way, the yield is 22.2% lower, the kappa number 42.5% higher, and the breaking length, burst index and tear index 6.2, 29.1 and 29.6%, respectively, lower than their optimum values; in any case, the strength properties increase although the pulp was suitably refining. [Copyright &y& Elsevier]