Study On Pre - Extraction Of Oxygen Pulping By

Resources and environment problems is the main challenge to humanity today. It is of special significance that clean pulping methods are developed for non-wood fiber, because it can ease our country’s demand pressure in wood fiber materials. In this thesis, eulaliopsis binata supplied by Yunnan Xinping Nanen sugar-paper Co., Ltd. was subjected to soda-oxygen pulping after preextraction, then ozone bleaching. The composition was separated from preextracted liquor, and the change of the structure of the dissolving lignin and dissolution component of carbohydrate was revealed using infrared spectrum (IR),1H-NMR and 13C-NMR.Eulaliopsis binata was individually preextracted by cold water, hot water, cold alkali, cold water and cold alkali, hot water and cold water, hot alkali, cold water and hot alkali, hot water and hot alkali. The suitable technology was hot alkali preextraction which removed 15.31% substrate out from the straw. Soda-oxygen pulping of the residual straw resulted in the pulp with 43.64% of screened yield with few reject,4.63 of Kappa number, especially, the brightness up to 70.0%ISO of the pulp can not easily observed in other soda-oxygen pulping processes.Through optimizing hot alkali preextraction of eulaliopsis binata, including alkali charges, duration time, and thereafter different washing methods, washing times for treated straw, the optimal results of soda-oxygen pulping was obtained under 10% of alkali charge for 10 min and washing twice with hot water. It gave rise to screen yield 45.95%, Kappa number 4.03, brightness 64.3% ISO, and viscosity 744 mL/g. Additionally, under above mentioned optimal preextraction, soda-oxygen pulping of eulaliopsis binata at Tmax 100℃ for 300 min greatly favored the pulp viscosity upon the acceptance of pulping effect.The pulp obtained from optimal preextraction and soda-oxygen pulping of eulaliopsis binata was bleached with ozone. The result is much better than we expected. The ozonation for 3 min with consumption of 0.26%O3 made the pulp brightness reach 81.3% ISO, whereas the decrement of the viscosity was 16 mL/g, only with the reduction of 1.9%. Prolonging ozonation time more than 10 min should be avoided because it would reinforece the degradation of the pulp, and the decrement of the viscosity would be beyond 110 mL/g. Suitable ozone bleaching would be advantageous to the improvement of the physical properties of the pulp. Therefore, combination of ozone bleaching with soda-oxygen pulping of eulaliopsis binata with preextraction could win strong pulp with better viscosity and high brightness above 80% ISO.