SIMPLIFIED KINETIC MODELING OF ALKALINE DELIGNIFICATION OF HEMP WOODY CORE

Alkaline delignification of hemp woody core was studied to support the development and optimization of an efficient and non-polluting alkaline pulping process. Shavings of hemp woody core were delignified isothermally at different temperatures with 1 M sodium hydroxide in a flow-through reactor. From literature data and from experimental data reported in this article. it appears that the initial delignification stage is completed before customary reaction temperatures are reached. Consequently, modelling of alkaline delignification kinetics can be restricted to the bulk and rest delignification stages, which can be described with two simultaneous first order reactions: L/L(0 = a2 exp (-k2t) + a3 exp (-k3t), with k(i) = A(i) exp -E(ai)/(RT). This equation has been solved integrally, calculating a2, a3, E(a2), E(a3), A2 and A3 for the best fit for the experimental data, resulting in an accurate description of the delignification reactions. This kinetic model has also been applied on literature data, supporting its validity towards alkaline delignification kinetics in general.