废纸浆纤维悬浮液屈服应力的主要影响因素研究

Research on the Major Influence Factors on Yield Stress of Recycled Fiber Suspension

中文关键词:  废纸浆  纤维悬浮液  流变特性  屈服应力  影响因素

Key Words:recycled pulp  fiber suspension  rheological behavior  yield stress  influence factors

中文摘要:

      基于屈服应力的纸浆纤维悬浮液的流变特性直接影响造纸过程的能耗和生产效率。利用SPSS统计分析软件，对浓度为1.5%～4.0%的废箱纸板（OCC）和旧报纸（ONP）浆纤维悬浮液，分别采用流变曲线回归法（RCR）和剪切应力梯度法（SSG）测得的屈服应力进行方程回归，并与原生木浆的进行比较分析。结果表明，ONP浆和OCC浆纤维悬浮液的屈服应力τy与浆料浓度Cm的回归方程采用RCR法测定的结果分别为τy=3.34C2.43m、τy=2.33C2.57m，采用SSG法测定的结果分别为τy=3.58C2.43m、τy=2.83C2.47m；在相同浓度下采用相同测定方法时，ONP浆纤维悬浮液的屈服应力均大于OCC浆纤维悬浮液的；对于相同浓度的同种浆料纤维悬浮液，采用SSG法测得的屈服应力要比RCR法测得的大，对ONP浆纤维悬浮液而言，约大5.1%～9.4%，而对于OCC浆纤维悬浮液，约大1.3%～13.9%；且Δτy在2.7～17.2 Pa之间，两种方法测得的屈服应力值偏差随纸浆纤维悬浮液浓度的增大而逐渐增大，即随着废纸浆纤维悬浮液浓度和纤维长宽比的增大，屈服应力增大。漂白针叶木浆纤维悬浮液的屈服应力明显大于ONP浆、OCC浆和阔叶木浆纤维悬浮液的。

Abstract:

      The yield-stress-based rheological behavior of pulp fiber suspension affects the energy consumption and production efficiency in papermaking. The yield stresses of slurry suspensions of old corrugated containers (OCC) and old news papers (ONP) with mass concentration of 1.5%~4.0% were evaluated by two measurement methods with the SPSS statistical analysis software and, then, compared with that from the virgin wood pulp. The results showed that the relations of yield stress τy and concentration Cm of the ONP pulp and OCC pulp based on rheological curve regression method (RCRM) satisfied respectively the exponential equations τy=3.34C2.43m and τy=2.33C2.57m, and τy and Cm based on shear stress gradient method (SSGM) satisfied respectively τy=3.58C2.43m and τy=2.83C2.47m; based on the same concentration and measurement method, the τy of ONP pulp was larger than that of OCC pulp, and, comparing on the same concentration and the same kind of pulp, τy based on SSGM was higher than that based on RCRM, 5.1%~9.4% higher for ONP pulp and 1.3%~13.9% higher for OCC pulp. The deviation of yield stress values measured by the two methods increased with the concentration increasing when the deviation was in the between of 2.7～17.2 Pa, which meant that τy of the pulp increased with the increase of concentration and fiber aspect ratio for waste paper. Taking a comparison, the τy of bleached softwood pulp was significantly larger than those of recycled pulp and hardwood pulp.