不同干燥方法对人工林樟子松木材干燥特性的影响

Effect of Different Drying Methods on the Drying Characteristics of Plantation-Grown Pinus sylvestris var.mongolica

【目的】研究不同干燥方法对人工林樟子松木材干燥特性的影响,为人工林樟子松木材高温节能绿色干燥提供理论基础。【方法】采用常规干燥(结合百度试验法测试的干燥特性,参照LY/T 1068—2012《锯材窑干工艺规程》并加以修正后制定)、高温干燥、太阳能-常规联合干燥和太阳能-高温联合干燥4种方法对人工林樟子松木材进行干燥,比较干燥速度、干燥时间、干燥质量和干燥能耗等干燥质量指标。【结果】干燥方法不同,木材干燥特性差异较大。百度试验法得出人工林樟子松木材的综合干燥特性等级为一级。采用太阳能预干燥,木材含水率从约80%降至约30%,干燥时间约78 h,白天干燥速度约1.07%•h^-1,夜间干燥速度约0.36%•h^-1;采用高温干燥和常规干燥,干燥初中期,高温干燥速度比常规干燥高136.15%和113.30%,干燥后期,仅高20.87%左右。太阳能与常规、高温联合干燥时间分别为92和86 h,约为常规和高温干燥的3~5倍;常规干燥后木材干燥质量等级为一级,高温干燥后木材干燥质量等级为二级,太阳能与常规、高温联合干燥后木材干燥质量为三级;高温干燥后木材材色变化严重,呈暗黄/深黄色;高温干燥较常规干燥节能48.53%,太阳能-常规联合干燥较常规干燥节能40.09%,较高温干燥节能17.08%,太阳能-高温联合干燥较常规干燥节能68.76%,较高温干燥节能57.76%。【结论】人工林樟子松木材采用高温干燥具有良好的干燥效果,在保证干燥质量的前提下效率明显提高。太阳能预干燥可节约大量能耗,太阳能-高温联合干燥可实现高效、绿色干燥。

【Objective】This current study was carried out to investigate the effects of different drying method on drying characteristics with the aim to provide theoretical bases for the high temperature energy-saving and green drying of plantation-grown Pinus sylvestris var.mongolica.【Method】Four drying methods including conventional drying,high temperature drying,solar-conventional joint drying and solar-high temperature joint drying were used to study the drying characteristics of P.sylvestris var.mongolica focusing on drying time,drying rate,drying quality,drying energy consumption,etc.【Result】The results showed that the drying characteristics of wood varied greatly with different drying methods.100℃showed that the comprehensive drying characteristics of P.sylvestris var.mongolica were grade 1.Moisture content of solar energy pre-drying wood was reduced from 80%to 30%,drying time was about 78 h,daytime drying speed was about 1.07%•h^-1,night drying speed was about 0.36%•h^-1.In the early and middle stages of drying,the drying speed of high temperature drying was higher than that of conventional drying by 136.15%and 113.30%,respectively,and only about 20.87%higher in the latter stage drying.The time of solar-conventional and solar-high temperature joint drying were 92 h and 86 h,respectively,which was about 3-5 times of conventional and high temperature drying.The wood drying quality after conventional drying was grade 1,and after high temperature drying was grade 2.The wood drying quality after solar energy joint drying was grade 3.High temperature drying made the wood color changed severely,turning dark yellow/dark yellow.Compared with conventional drying,high temperature drying could save 48.53%energy.Compared with conventional drying and high temperature drying,solar-conventional joint drying could save 40.09%and 17.08%energy,solar-high temperature joint drying could save 68.76%and 57.76%energy.【Conclusion】The high temperature drying of P.sylvestris var.mongolica presented a good drying effect.Solar predrying could save a lot of energy consumption,whereas the joint of solar energy and high temperature drying could show efficient and green drying.