Study On Delignification Properties Of Populus Deltoides NL351and2-2in KP Pulping And Oxygen Delignification

Populus deltoides is introducing and cultivating in China as fast-growing wood. In thispaper, from these aspects of growth traits, wood chemical composition and fiber morphology, toprovide a certain basis for fast-growing pulpwood of fine varieties selection and orientedcultivation and promotion. Preliminary analysised and evaluated the features of KP pulping andoxygen delignification of populus deltoides NL351(P.deltoides.harvard×P.deltoides.lux,poplar351) and new clone2-2(Populus deltoides T120half sibs family, poplar2-2), optimized asuitable process for KP pulping and oxygen delignification. The main results are as follows:Poplar351’s and poplar2-2’s average growth of individual tree volume is0.431m3and0.567m3, poplar2-2is worthy extending as fast-growing wood as poplar351. Poplar2-2’s and351’s basic density is0.370g/cm3and0.417g/cm3. They are all suitable for the manufacture ofhigh yield pulp and chemical pulp.The fiber length of poplar351and2-2in3th/6th/9thyear is0.98mm/1.11mm/1.20mm and1.07mm/1.18mm/1.23mm, the fiber width of poplar351and2-2in3th/6th/9thyear is20.7μm/22.1μm/22.9μm and21.5μm/22.7μm/23.1μm, the length-width ratio is more than45.They had met the requirements of paper making raw materials. Chemical composition analysisof poplar351and2-2had found that the total lignin content is low (21.95%and22.77%) andthe total cellulose content is high (79.81%and77.54%). They are both excellent fast-growingpulpwood, to become useful in3-5years.Cooking temperature and time on the performance of the pulping into the largest, followedby the alkaline dosage, then, followed by sulphidity. The optimized condition of KP pulping:alkaline dosage is16.0%, sulphidity is25.0%, cooking time is90min, the highest cookingtemperature is165℃, liquor ratio is1：4. When poplar351and2-2under this condition, theyield of screened pulp is51.6%and50.7%, kappa number is16.9and17.4, viscosity is36.0mPa·s and32.0mPa·s. Compared with poplar2-2KP pulp, poplar351’s is higher yield,lower kappa number, higher viscosity. Poplar351is more suitable for KP pulp, resultsconsistent with the analysis of chemical composition and fiber morphological. Comprehensiveevaluation, both poplar351and poplar2-2are high quality raw materials for KP pulp.Alkaline dosage on the performance of the poplar KP pulp oxygen delignification is mostaffected, followed by reaction temperature, followed by reaction time and oxygen pressure.Theoptimized condition of oxygen delignification for poplar351and2-2are as follows: alkalinedosage is1.5%and1.0%, reaction temperature is90℃, reaction time is80min, oxygenpressure is0.5MPa and0.7MPa, pulp consistency is10%, amount of MgSO4is0.5%. Afterdelignification, to the poplar351and2-2, pulp yield is98.3%and98.4%, kappa number is8.0and8.5, viscosity is26.7mPa·s and26.6mPa·s.