桉木冷碱浸渍-挤压-硫酸盐法制浆的研究

Eucalyptus Kraft Pulping with Pretreatment of Cold Alkali Impregnation and Compression

中文关键词:  桉木  硫酸盐法制浆  冷碱浸渍  挤压

Key Words:eucalyptus kraft pulping  alkali impregnation  compression

中文摘要:

      将冷碱浸渍-挤压作为木片预处理方法,并应用于桉木硫酸盐法制浆的前段。探讨了冷碱浸渍-挤压的最佳工艺条件,研究了蒸煮工艺条件对预处理后料片蒸煮结果的影响,对比了未预处理原料与预处理后料片硫酸盐法蒸煮所得纸浆的强度性能。结果表明,木片经过冷碱浸渍-挤压后,易于蒸煮,从而可减少蒸煮用碱量或降低最高蒸煮温度、缩短保温时间,且蒸煮的均匀性得到改善,筛渣率降低、纸浆强度性能提高。最佳预处理工艺条件为浸渍用碱量2%,浸渍时间2 h,温度25℃,液比1∶5,挤压压缩比3∶1；与未预处理原料硫酸盐法蒸煮(用碱量21%)相比,预处理后料片在总用碱量(浸渍用碱量2%,蒸煮用碱量19%)相同的情况下,成浆卡伯值降低了1.7,细浆得率只降低0.14个百分点,且纸浆强度性能更优,其中,抗张指数、耐破指数、耐折度分别提高了7.0%、5.2%、66%,撕裂指数与未预处理原料硫酸盐法蒸煮所得纸浆相近。

Abstract:

      Cold alkali impregnation and compression were used as pretreatment in eucalyptus kraft pulping. The optimum conditions of cold alkali impregnation and compression were discussed. And, the influence of cooking conditions on the kraft pulping of pretreated wood was studied. The kraft pulp strength of pretreated wood was compared with that of unpretreated. The results showed that the optimum conditions of alkali impregnation were NaOH dosage 2%, time 2 h, temperature 25℃, liquor to wood ratio 1∶5, and the compression ratio 3∶1. Compared with kraft pulping of unpretreated woodchips (NaOH dosage 21%), the kappa number of pulp decreased 1.7 and the pulp yield decreased only 0.14% when the total NaOH dosage (2% for impregnation, 19% for pulping) of pretreated kraft pulping was the same as unpretreated. And the pulp strength of pretreated kraft pulping was better than the pulp of unpretreated pulping. The tensile index, burst index and folding endurance of the handsheets of pretreated kraft pulp increased by 7.0％, 5.2％and 66％compared with the unpretreated wood kraft pulp, while the tear index was similar.