Delignification kinetic modeling of NH4OH-KOH-AQ pulping for bagasse

The pulping runs for bagasse were carried out by using NH4OH-KOH-AQ as cooking liquor. IR was employed to study the characteristic change of bagasse and obtained pulp. The delignification mechanisms and kinetics of NH4OH-KOH-AQ pulping for bagasse were investigated. The dissolution of lignin proceeds could be divided into three distinct phases, named a bulk phase of delignification, a supplementary phase, and a residual phase. The rate of delignification reaction was found to be 1.0, 0.72 and 0.14 with respect to residual lignin, hydroxide ion and AQ, respectively. Values were obtained for the rate constants at a number of temperatures and the activation energy was found to be 45.29 kJ/mol. A kinetic model of delignification could be expressed as −dLdt=5.25×105exp(−5448T)L[OH]0.72[AQ]0.14.