摘要
采用碱回收绿液对杨木木片进行预处理,研究了预处理后硫酸盐法蒸煮过程中脱木素反应历程及NaOH的消耗过程。研究表明,采用绿液预处理后,杨木木片得率为73.1%,木素脱除率为32.54%。预处理后的蒸煮过程中,在初始脱木素段,木素脱除率为14.52%;在大量脱木素段,木素脱除率为42.62%;残余脱木素段,木素脱除率仅为3.41%。这3个阶段的木素脱除率比传统硫酸盐法分别降低了3.55、19.38和9.11个百分点。NaOH几乎全部消耗在蒸煮初期和大量脱木素段,这2个阶段NaOH分别消耗了57.71%和42.29%;Na2S质量浓度在蒸煮初期逐渐减小,蒸煮的中后期又逐渐增大。绿液预处理硫酸盐法蒸煮不仅能提高脱木素选择性,还能提高蒸煮后浆料得率(达到50.8%),比传统硫酸盐法浆料得率(47.9%)提高2.9个百分点。
Green liquor from alkali recovery process was used in the pretreatment of poplar wood chips.The delignification reaction course and the consumption process of alkaline during subsequent kraft pulping were studied.After green liquor pretreatment poplar wood chips were cooked under conventional kraft cooking conditions.Black liquor from cooking process was used to analyze the lignin content and the concentration of NaOH and Na2S by acid precipitation method and titration method,respectively.For kraft pulping after green liquor pretreatment,the yield was 73.1％,delignification rate was 32.54％.Contrasted to the traditional kraft pulping,delignification velocity was almost steady during the cooking process.On the initial delignification phase,delignification rate was 14.52％.On the bulk delignification phase and residue delignification phase,delignification rates were 42.62％ and 3.41％,respectively.Compared to the traditional kraft pulping,delignification rates of three delignify phases reduced by 3.55,19.38 and 9.11 percent points,respectively.NaOH was almost consumed at the initial delignify phase and bulk delignify phase with the consumption of 57.71％ and 42.29％,respectively.The concentration of Na2S decreased firstly,and reached to a minimum of 1.09 g/L in 1.25 h,but after 1.25 h,since sulfur precipitated from ligninsulfonate,the concentration of Na2S began to increase gradually.Kraft pulping with green liquor pretreatment could not only improve the selectivity of delignification,but also reduce the degradation of carbohydrates.The total cooking yield was 50.8％,increased by 2.9 percent points,compared to the traditional kraft pulping.
出处
《中国造纸学报》
CAS
CSCD
北大核心
2013年第4期12-17,共6页
Transactions of China Pulp and Paper
基金
国家自然科学基金(31000282)
辽宁省教育厅优秀人才项目(LJQ2011053)
辽宁省创新团队项目(2008T014)
关键词
绿液
预处理
硫酸盐法制浆
脱木素历程
碱液浓度
green liquor
pretreatment
kraft pulping
delignification reaction course
alkali concentration
