Effect of temperature on the kinetics of pulp ozonation

The kinetics of delignification and cellulose chain scission of hemlock kra ft pulp are studied at high consistency over a temperature range of 0-30 de greesC for conventional ozonation, and of -54 to +30 degreesC for ethanol-a ssisted ozonation. The experimental results show that temperature has virtu ally no effect on the kinetics of delignification, and only a small effect on that of cellulose degradation at normal ozone consumptions. However at l onger ozonation times (equivalent to excessive ozone charges), the cellulos e degradation is significantly higher at 30 degreesC than at 0 degreesC. Th ese results are in agreement with the shrinking-core kinetic model descript ion of delignification during ozone bleaching, and are consistent with the small effect of temperature on the combined influence of the solubility and diffusivity of ozone in the liquid contained in the fibre wall.