胡桃木板材高频真空二次干燥

Radio Frequency/Vacuum Re-drying of Walnut Lumber

本文以胡桃木(Juglans nigra,Linn)窑干地板材为试材,在真空条件下(绝对真空7.0~7.6 kPa)进行高频真空二次干燥,对干燥质量、干燥能耗与成本、脱水效率及干燥速度进行了分析。结果表明:高频真空二次干燥后无干燥缺陷产生、木材的含水率更加均匀;干燥过程中材料升温能耗占全部能耗的21%,整个干燥过程高频加热能耗占比为68%,干燥成本为148元/m^3。虽然干燥成本较高,但干燥质量优异、时间明显缩短,具有综合优势;木材温度超过环境压力对应沸点时。

Walnut kiln dried boards for flooring （Juglans nigra, Linn） were re-dried through radio fre- queney/vaeuum （RF/V） under vacuum condition （7.0 - 7.6 Kpa）. The drying quality, drying energy eon- sumption and cost, effieieney of dehydration and drying rate were analyzed after drying. The results indi- cated that no drying defeets occurred and the more evenness of moisture contents （MC） of walnut boards ; the energy eonsumption for materials heating during temperature rising phrase oceupied 21% of total ener- gy consumption, and the energy consumption of RF heating oceupied 68% during the whole process. Al- though with relatively high drying cost as 148 yuan/m3, comprehensive advantages were presented for the exeellent wood quality and shorted drying times. The effieieney of dehydration increased and maintained at certain level after wood temperature arrived boiling point corresponded to the vacuum pressure. Drying rate of bounded water at low MC for RF/V was faster than that in Kiln drying.