纸张干燥特性曲线影响因素实验研究

Experimental Study on Influence Factors of Paper Drying Characteristic Curve

中文关键词:  纸张干燥  特性曲线  影响因素

Key Words:paper drying  drying characteristic curve  influence factors

中文摘要:

      采用控制变量法，研究了纤维原料种类、成纸定量、纸浆打浆度、压榨压力和干燥温度5个因素对纸张干燥特性曲线的影响。结果表明，纤维原料种类和纸浆打浆度对纸张干燥特性曲线影响较小，但纸浆打浆度会影响纸张干燥前初始含水率，打浆度越大，纸张干燥前初始含水率越高；纸张定量与厚度正相关，对纸张干燥特性曲线影响显著，定量越大，纸张越难干燥；压榨降低了纸张干燥初始含水率，加速了干燥过程，可能的原因是挤压后，纸张中部分难干燥的毛细管水转变成了容易干燥的游离水；由于纸张干燥是传热与传质同时发生的过程，干燥温度越高，传热动力大，促使蒸发传质发生，干燥越容易。

Abstract:

      The effects of fiber material， paper basis weight， pulp beating degree， pressing pressure and drying temperature on paper drying characteristic curve were researched in the study. The experimental results showed that: different fiber material and pulp beating degree had little influence on the paper drying characteristic curve， but pulp beating degree affected the initial moisture content of paper drying， the higher pulp beating degree， the higher the initial moisture content was. Paper basis weight had obvious influence on paper drying characteristic curve because of its positive corrilation with paper thickness， the greater the paper basis weight， the harder it was to dry. Pressing pressure not only affected the paper initial moisture content， but also accelerated the drying process. The possible reason was that after the paper was pressed， part of the capillary water which is difficult to dry changed to free water which is easy to dry. Because of the coupling process of heat and mass transfer in paper drying， the higher drying temperature， the greater heat and mass transfer power， and the easier drying occurs．