| Abstract:The effects of temperature, oxygen pressure, alkali charge, and time on the formation of methanol during oxygen delignification (OD) of eucalyptus kraft pulp were investigated, from which a kinetic model for predicting the methanol formation during the OD process was established. The results showed that the model can provide a good prediction for the methanol formation during OD of different kappa number pulps at different process conditions. The active energies and the reaction orders of NaOH concentration and oxygen pressure for the methanol formation reaction of high/low kappa number pulps are 55.4/49.3 kJ/mol, 1.02/0.362, 0.472/0.299, respectively. And also, at the given target kappa number (10) of the subsequent OD process, the methanol formation in the process for the high kappa number pulp can be considerably reduced (by 12%). The amounts of methanol formed per unit kappa number reduction during OD process of the pulps from different raw materials are different, which are 29.1, 11.0, and 13.8 mg/L for eucalyptus, southern pine, and wheat straw pulps, respectively. |
