利用时域核磁共振研究木材干燥过程水分状态变化

doi:10.11707/j.1001-7488.20141215

摘要/Abstract

摘要：

以新疆杨幼龄材为研究对象,以水分子中的H质子为探针,利用时域核磁共振技术探究木材干燥过程中水分状态变化与迁移.通过对干燥过程中水分变化的自由感应衰减曲线(FID)和横向弛豫时间(T2)进行测定与分析,探究木材内部水分状态变化及迁移过程.结果表明: 利用时域核磁共振技术测得新疆杨的理论含水率(71.90%)与实际含水率(73.74%)相差1.84%.通过T2分布描述木材干燥过程中水分的迁移,例证在木材干燥的初始阶段结合水也有缓慢减少的现象.通过不同组分水的T2弛豫时间对应的峰面积定量计算出新疆杨幼龄材中不同状态水的含量.对干燥过程中的自由水、结合水及木材总含水量的变化建立相应的数学模型.

关键词: 木材干燥, 时域核磁共振, FID, T2, 自由水, 结合水, 新疆杨, 幼龄材

Abstract:

Water states and migration in juvenile Xinjiang poplar (Populus alba var. pyramidalis) drying was studied by time-domain nuclear magnetic resonance (TD-NMR). Water in wood drying was investigated through free induction decay curve (FID) and transverse relaxation time(T2) of proton sensor in water molecules. The results showed that the difference was 1.84% between theoretical moisture content (71.90%) and actual one (73.74%) by using TD-NMR technique; the T2 distribution revealed the water states and migration in wood drying, also the bound water was slowly lost in the drying initial stage. The mass of different water states in juvenile wood during drying could be calculated according to peak areas of T2 distributing. Finally mathematical models for free water, bound water and the total water migration were developed in the drying process.

Key words: wood drying, time-domain NMR, FID, T2, free water, bound water, Populus alba var. pyramidalis, juvenile wood

中图分类号:

S781.33

张明辉, 李新宇, 周云洁, 高玉磊. 利用时域核磁共振研究木材干燥过程水分状态变化[J]. 林业科学, 2014, 50(12): 109-113.

Zhang Minghui, Li Xinyu, Zhou Yunjie, Gao Yulei. Water Status Change in Wood Drying Studied By Time-Domain NMR[J]. Scientia Silvae Sinicae, 2014, 50(12): 109-113.

参考文献

蒋佳荔, 吕建雄. 2008. 干燥处理木材动态黏弹性的含水率依存性. 林业科学,44 (9): 118-124.
(Jiang J L, Lü J X. 2008. Moisture dependence of dynamic viscoelastic properties for dried woods. Scientia Silvae Sinicae,44 (9): 118-124. [in Chinese] )
李大纲. 1997. 马尾松木材干燥过程中水分的非稳态扩散. 南京林业大学学报, 21 (1): 75-79.
(Li D G. 1997. Unsteady-state moisture transfer on wood drying of Pinus massoniana. Journal of Nanjing Forestry University, 21 (1): 75-79. [in Chinese] )
李贤军, 孙伟圣, 周涛, 等. 2012. 微波处理中木材内温度分布的数学模拟. 林业科学, 48 (3): 117-121.
(Li X J, Sun W S, Zhou T, et al. 2012. Mathematical modeling of temperature profiles in wood during microwave heating. Scientia Silvae Sinicae, 48 (3): 117-121. [in Chinese] )
李贤军, 吴庆利, 姜伟, 等. 2006. 微波真空干燥过程中木材内的水分迁移机理. 北京林业大学学报, 28 (3): 150-153.
(Li X J, Wu Q L, Jiang W, et al. 2006. Mechanism of moisture movement in wood during microwave-vacuum drying. Journal of Beijing Forestry University, 28 (3): 150-153. [in Chinese] )
李贤军, 蔡智勇, 傅峰. 2010. 干燥过程中木材内部含水率检测的X射线扫描方法. 林业科学, 46 (2): 122-127.
(Li X J, Cai Z Y, Fu F. 2010. A new X-ray scanning method for measuring the internal moisture content in wood drying. Scientia Silvae Sinicae, 46 (2): 122-127. [in Chinese] )
刘鲁滨. 2013. 干燥过程中木材内水分的移动. 黑龙江科技信息,(27): 264.
刘志军, 张璧光, 刘智. 2005. 微波干燥过程中木材内部水分移动机理初探. 北京林业大学学报, 27 (S1): 51-55.
(Liu Z J, Zhang B G, Liu Z. 2005. Mechanism of internal moisture migration in wood during the microwave drying. Journal of Beijing Forestry University, 27 (S1): 51-55. [in Chinese] )
王喜明, 贺勤. 2005. 桉树木材干燥过程曲线的研究. 北京林业大学学报, 27 (S1): 13-17.
(Wang X M, He Q. 2005. Different curves in the wood drying of eucalyptus. Journal of Beijing Forestry University, 27 (S1): 13-17. [in Chinese] )
伊松林, 张璧光, 常建民. 2003. 木材真空-浮压干燥过程中吸着水迁移特性分析. 北京林业大学学报, 25 (6): 60-63.
(Yi S L, Zhang B G, Chang J M. 2003. Analysis of characteristics of absorbed water movement in wood drying process under vacuum-floating pressure. Journal of Beijing Forestry University, 25 (6): 60-63. [in Chinese] )
战剑锋, 顾继友, 蔡英春. 2009. 落叶松板材常规干燥过程的动态机械吸附特性. 北京林业大学学报, 31 (2): 108-113.
(Zhan J F, Gu J Y, Cai Y C. 2009. Dynamic mechano-sorptive characteristics of larch timber during conventional drying process. Journal of Beijing Forestry University, 31 (2): 108-113. [in Chinese] )
战剑锋, 顾继友, 艾沐野. 2004. 白桦木材干燥过程横纹流变特性的初步研究. 林业科学, 40 (5): 174-179.
(Zhan J F, Gu J Y, Ai M Y. 2004. The preliminary study on drying process traverse strains of asian white birch. Scientia Silvae Sinicae, 40 (5): 174-179. [in Chinese] )
战剑锋, 顾继友, 蔡英春. 2008. 落叶松板材干燥过程的结合水扩散系数. 南京林业大学学报, 32 (4): 6-10.
(Zhan J F, Gu J Y, Cai Y C. 2008. Bound water diffusion coefficient of larch timber during drying process. Journal of Nanjing Forestry University: Natural Sciences Edition, 32 (4): 6-10. [in Chinese] )
张璧光, 谢拥群. 2006. 木材干燥的国内外现状与发展趋势. 干燥技术与设备, 4 (1): 7-14.
(Zhang B G, Xie Y Q. 2006. Research and development of wood drying. Drying Technology & Equipment, 4 (1): 7-14. [in Chinese] )
Almeida G, Gagne S, Hernandez R E. 2007. A NMR study of water distribution in hardwoods at several equilibrium moisture contents. Wood Sci Technol, 41(4): 293-307.
Araujo C D, MacKay A L, Hailey J R T, et al. 1992. Proton magnetic resonance techniquesfor characterization of water in wood: application to white spruce. Wood Sci Technol, 26: 101-113.
Araujo C D, MacKay A L, Whittall K P, et al. 1993. A diffusion model for spin-spin relaxation of compartmentalized water in wood. J Magn Reson B, 101 (3): 248-261.
? ermák, P, Trcala M. 2012. Influence of uncertainty in diffusion coefficients on moisture field during wood drying. International Journal of Heat and Mass Transfer, 55 (25/26): 7709-7717.
Merela M, Oven P, Serša I, et al. 2009. A single point NMR method for an instantaneous determination of the moisture content of wood. Holzforschung, 63 (3): 348-351.
Nanassy A J. 1973. Use of wide line NMR for measurement of moisture content in wood.Wood Sci, 5(3): 187-193.
Peng Y, Li F, Yang F, et al. 2012. Effect of steam pretreatment on wood moisture content and characteristics of vacuum drying. Forestry Studies in China,14 (4): 315-319.
Sharp A R, Riggin M T, Kaiser R, et al. 1978. Determination of moisture content of wood by pulsed nuclear magnetic resonance. Wood Fiber, 10 (2): 74-81.
Xu Y, Araujo C D, Mackay A L, et al. 1996. Proton spin-lattice relaxation in wood: T1 related to local specific gravity using a fast-exchange model.Journal of Magnetic Resonance: Series B, 110 (1): 55-64.

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