木材纤维对撞流干燥特性的研究

该文以垂直 倾斜半环多级组合对撞流干燥系统为研究对象 ,通过对木质纤维进行初含水率、气流流量、气流温度和带载率等系统参数的实验研究 ,探讨木质纤维的对撞流干燥特性 .研究结果表明 :木质纤维干燥的气流温度在 90℃时即可达到当前中密度纤维板生产中利用气流干燥所普遍采用的 12 0℃才能达到的效果 ;气流流量的变化除引起流场变化外 ,还会影响纤维在对撞腔内的停留时间和穿透深度 ,从而影响干燥效果 ;带载率的变化在一定范围内不会影响纤维干燥的质量 ,但影响系统产量 ;系统能够适应现有生产系统纤维原料初含水率的变化 ,干燥品质不受初含水率的影响 ;采用对撞流干燥系统可以使设备管道长度大大缩短 ,从现有气流干燥使用的 10 0m以上的长度 ,缩短为 13 5m .

Study on the characteristics of impinging stream drying of wood fiber

This study focuses on the influence of initial fiber moisture content, air temperature, air flux and loading ratio on the drying efficiency and quality of wood fiber in impinging stream-drying system. A vertical-inclined semi-circular combination impinging stream drying system is applied to perform the drying of wood fiber. The results demonstrate that using the air temperature of 90℃ in the impinging stream system, the wood fiber is able to reach the quality parameters required by MDF hot press process, while in the normal airflow fiber drying system, to reach the same parameters, the required air temperature is 120℃. The change in air flux will not only causes the change in turbulence, but also affects the stay time of wood fiber in impinging space and the distance to which the particulates move into adverse-flow, and thus affects drying effect. Fiber loading ratio does not have appreciable effects on fiber quality; however, it may influence the production of impinging stream drying system. The initial fiber moisture content appears little impact on the final moisture content in the system discussed, therefore, the impinging drying system may perform quite well in drying wood fiber with different initial moisture contents, this enables the impinging stream drying system to process wood fiber from any MDF refiner. Moreover, applying impinging stream drying system may shorten the length of pipe to 13.5 m, whereas in normal airflow drying system the length of the pipe should be 100 m or more.