Kratf Pulping And The Kinetic Of Phyllostachys Heterocycla CV Pubescens With Prehydrolysis

The process of kraft pulping combined with water prehydrolysis for the production ofdissolving pulp from Phyllostachys heterocyclava cv pubescens was optimized in thispaper, The kinetic of water prehydrolysis and kraft pulping was studied to provide thetheory basis and technical support for the dissolving pulp production based on bamboofibers.The average fiber length of Phyllostachys heterocycla cv pubescens is categorized aslong fiber with moderater width, compared to wood materials, the chemical composition ofPhyllostachys heterocycla cv pubescens is of lower lignin content and nitrate-ethanolcellulose content, while the ash, extractive, and pentosan content is much higher. Todecrease its non-cellulosic components, and to increaseα-cellulose content in theprehydrolysis and kraft pulping for the production of dissolving pulp based onPhyllostachys heterocycla cv pubescens is of great importance.The kinetic model of water prehydrolysis was established, The result showed that, thekinetic of hemicellulose dissolution was in accord with the two-way model, and thetemperature was the main influential factors in the water prehydrolysis process. When theprehydrolysis temperature was 140℃, 150℃, 160℃, 170℃, the fast reaction rateconstants was1.9×10 3min^-1,3.3×10 3min^-1,5.6×10 3min^-1,9.9×10 3min^-1respectively,while the slow reaction rate constants was7.4×10 5min^-1,1.0×10 4min^-1,4.1×10 4min^-1,1.0×10 3min^-1respectively. The fast and slow activation energy was 83.29 kJ·mol^-1and138.79 kJ·mol^-1respectively according to Arrhenius Empiric Equation.The kinetic model of kraft cooking for water prehydrolysis was also established, thelignin removing reaction of Phyllostachys heterocycla cv pubescens comformed to thetwo-order reaction, When the cooking temperature was 100℃, 120℃, 140℃, 160℃, thereaction rate constants was6.0×10 5,2.6×10 4,5.2×10 4,6.9×10 4respectively.Activation energy of kraft pulping for water prehydrolysis of Phyllostachys heterocycla cvpubescens was 54.60 kJ·mol^-1in water prehydrolysis process according to ArrheniusEmpiric Equation.The process optimization of water prehydrolysis and kraft cooking for Phyllostachys heterocycla cv pubescens revealed that the P-factor was 1000 for water prehydrolysis andH-factor was 1000 for kraft pulping, and the cooking condition were active alkali charge17%（Na₂O）, sulfidity 20%. The brown dissolving pulp based on the process was ofα-cellulose 94.55%, viscosity 1096 ml·g^-1, fine pulp yield 33.56%, Kappa 10.76 andpentosan conten 4.81%.