Oxygen Delignification Ivtensified By Surfactant For Sulfate Bamboo Pulp

With the development of economy in China, the demand for paper and paper products increases. The limited forestry resources results in a serious lack of wood pulp, no-wood fiber is still an important raw material for papermaking. Meanwhile, the unreasonable fiber raw material structure, small scale, poor facilities resulted in a serious environmental pollution which restricted the sustainable development of China's paper industry. On the other hand, China is one of the bamboo rich countries in the world and occupies the first place in amount of bamboo resource, the area and the accumulation of bamboo forest. Furthermore, the fiber and chemical composition of bamboo are suitable for pulping. Therefore, in order to utilize bamboo resource more effectively, lighten the pressure for wood fiber demand and reduce the pollution of paper industry. The oxygen delignification and TCF bleaching were studied in the thesis. some surfactants as additive of oxygen delignification were selected by a large number of tests. The optimization of oxygen delignification and oxygen delignification bossted by additives were studied, which will offer support for producing high quality bamboo pulp in pulp and paper industry.Firstly as the kappa numbe of bamboo pulp was 22.6, the viscosity was 1086 ml·g-1, the brightness was 24.1%ISO. The optimal conditions of oxygen delignification were as follows: NaOH charge 3%, MgSO4 charge 0.5%, temperature 100℃, reaction time 80min, oxygen pressure 0.5Mpa. After oxygen delignification, the kappa number was 12.5, the delignification rate was 44.7%, the viscosity was 941.6 ml·g-1, the viscosity loss was 9.7%, brightness was 34.8%ISO.By studying the anionic surfactants, cationic surfactants, nonionic surfactants on the oxygen delignification three non-ionic surfactant OB3,OB5,OB9,and three anionic surfactants OA6,OA12,OA15 were selected by a large number of tests. By coordinate with each other, to find the better proportion of each distribution, the better dditive X of oxygen delignification for bleaching follow-up was find.As the kappa numbe of bamboo pulp was 22.6, the viscosity was 1086 ml·g-1, the optimal conditions of oxygen delignification bossted by additives were as follow: additive X charge 0.3%, H2O2 charge 0.5%, NaOH charge 2.5%, MgSO4 charge 0.5%, temperature85℃, reaction time 60min, oxygen pressure 0.5Mpa. After oxygen delignification, the kappa number was 9.7, the viscosity was 964.3 ml/g, the brightness was 44.3%ISO. In the optimized conditions, the additives enhanced oxygen delignification compare to conventional oxygen delignification. the delignification rate was increase 10.1%, the brightness was raised 9.5%ISO, the temperature was reduced 15℃, the reaction time was decreased 20 min, the NaOH charge was reduced 0.5%.Bamboo pulp chelated with DTPA after oxygen delignification, The optimal conditions were pulp consistency 5%, The initial pH was 4, DTPA charge was 0.3%, temperature 60℃, reaction time 60min, DTPA charge 0.3%; The optimal conditions of Pa were: pulp consistency 10%, pH 6, temperature 60℃, reaction time 60min, the Pa charge was 0.6%, The optimal conditions of H2O2 bleaching were the H2O2 charge 4%, NaOH charge 1.5%, Na2SiO3 charge 1.5%, temperature 90℃, reaction time 120min, pulp consistency 10%; The optimal conditions of Po were oxygen pressure 0.3Mpa, pulp consistency 10%, NaOH charge 3%, Na2SiO3 charge 1.5%, MgSO4 charge 0.5%, H2O2 charge 3%, temperature 110℃, bleaching time 60min.TCF bleaching of bamboo pulp was conducted after the oxygen delignification, the bamboo pulp's brightness can reach above 80% ISO by O2QPO,OQPOP,OQPaP, which has good viscosity, what's more the pulp's brightness was OQPOP >OQPaP>OQP, the pulp's viscosity was OQPaP>OQP>OQPOP, After TCF bleaching, the additives enhanced oxygen delignification compared to conventional oxygen delignification, the former had the better selectivity, higher brightness, and the better viscosity. compering to CEH bleaching, TCF bleaching had the high viscosity and better strength properties in the similar brightness.