Water Distribution in Poplar during High-Temperature Drying Process Studied by Time-Domain Nuclear Magnetic Resonance

doi:10.11938/cjmr20160313

Abstract

Abstract:

Moisture in wood affects its physical properties. Time-domain nuclear magnetic resonance (TD-NMR) technique can be used to monitor water state changes and migration, providing a powerful tool to study changes of water in wood during drying and product processing. In this study, water states and migration in Beijing poplar were monitored by TD-NMR during high-temperature drying. Free induction decay (FID) and transverse relaxation time (T₂) of water were measured. The results showed that both FID and T₂ signals were linearized with moisture content, hence the moisture content in the whold drying process can be calculated. Free water with long relaxation time in heart wood showed a trend of first decrease and then increase and decrease again at last, this phenomenon did not happen in the sap wood. In the heart wood, the most abundant moisture is the water with magnitude of 10 ms relaxation time. But the moisture content of each water state has small difference in sap wood, and the most abundant moisture is the water with magnitude of 100 ms relaxation time. During high temperature drying process, the moisture percentage decrease faster in sap wood than that in heart wood, and the evaporation rate of free water is significantly faster than the bound water.

Key words: time-domain NMR (TD-NMR), water distribution, transverse relaxation time (T₂), Beijing poplar, high temperature drying

CLC Number:

O482.53

GAO Yu-lei, LI Xin-yu, LEI Peng, ZHANG Ming-hui. Water Distribution in Poplar during High-Temperature Drying Process Studied by Time-Domain Nuclear Magnetic Resonance[J]. Chinese Journal of Magnetic Resonance, 2016, 33(3): 479-490.

References

[1] Jiang Ze-hui(江泽慧), Chen Xu-he(陈绪和), Ye Ke-lin(叶克林), et al. World wood utilization trends(世界木材利用发展态势)[J]. China Wood Industry(木材工业), 2010, 24(1): 1-4.

[2] Liu Wen-jin(刘文金). Influence of wood shrinkage and swelling on solid wood furniture design(木材干缩湿胀对实木家具设计的影响)[J]. China Forest Products Industry(林产工业), 2002, 29(3): 29-31.

[3] Jiang Ze-hui(江泽慧), Wang Xi-ming(王喜明). Drying and Collapse of Eucalypts Plantation (桉树人工林木材干燥与皱缩)[M]. Beijing(北京): China Forestry Publishing House(中国林业出版社), 2003.

[4] Zhang Bi-guang(张璧光), Xie Yong-qun(谢拥群). Research and development of wood drying(木材干燥的国内外现状与发展趋势)[J]. Dring Technology & Equipment(干燥技术与设备), 2006, 4(1): 7-14.

[5] Miao Ping(苗平). Water Movement and Heat Transfer During High Temperature Drying of Masson' Pine(马尾松木材高温干燥的水分迁移和热量传递)[D]. Nanjing(南京): Nanjing Forestry University(南京林业大学), 2000.

[6] Skaar C. Wood-water relations[J]. Forest Ecol Manag, 1981, 31(1, 2): 121-123.

[7] Kawai S. Moisture movement in below fiber saturation point[J]. Mokuzai Gakkaishi, 1978, 24(5): 273-280.

[8] Zhou Yong-dong(周永东), Li Xiao-ling(李晓玲). Comparison of high-temperature drying and conventional drying of Chinese fir lumber(人工林杉木高温干燥与常规干燥的比较研究)[J]. Journal of Beijing Forestry University(北京林业大学学报), 2005, 27(S1): 18-21.

[9] Yoshda T, Hashizume T, Fujimoto N. High-temperature drying characteristics on boxed-heart square timber of karamatsu and sugi-influences of high temperature conditions with low humidity on drying properties[J]. Wood Industry, 2000, 55(8): 357-362.

[10] Li Da-gang(李大纲), Gu Lian-bai(顾炼百). Effects of high temperature drying on wood properties of poplar(高温干燥对杨木主要力学性能的影响)[J]. Journal of Nanjing Forestry University (南京林业大学学报), 2000, 24(1): 38-40.

[11] Xu Xin-wu(徐新吾). High temperature of thick ash panel(水曲柳厚板材的高温干燥)[J]. Journal of Nanjing Forestry University(南京林业大学学报), 1982, 1(1): 66-84.

[12] Sun Bing-hu(孙丙虎). Study on Characteristics of Water Movement and Transverse Relaxation on Wood During Different Drying Methods(不同干燥方法的木材水分迁移与横向弛豫特性研究)[D]. Hohhot(呼和浩特): Inner Mongolia Agricultural University(内蒙古农业大学), 2012.

[13] Ma Da-yan(马大燕), Wang Xi-ming(王喜明), Zhang Ming-hui(张明辉). Mechanism of water sorption during adsorption process of wood studied by NMR(核磁共振研究木材吸着过程中水分吸附机理)[J]. Chinese J Magn Reson (波谱学杂志), 2011, 28(1): 135-141.

[14] Li Chao(李超). Study on the Relaxation Characteristics of Water in Wood by TD-NMR(木材中水分弛豫特性的核磁共振研究)[D]. Hohhot(呼和浩特): Inner Mongolia Agricultural University(内蒙古农业大学), 2012.

[15] Zhang Ming-hui(张明辉), Li Xin-yu(李新宇), Zhou Yun-jie(周云洁), et al. Water status change in wood drying studied by time-domain NMR(利用时域核磁共振研究木材干燥过程水分状态变化)[J]. Scientia Silvae Sinicae(林业科学), 2014, 50(12): 109-113.

[16] Labbe N, DeJeso B, Lartigue J C, et al. Time-domain ¹H NMR characterization of the liquid phase in greenwood[J]. Holzforschung, 2006, 60(3): 265-270

[17] Menon R S, Mackay A L, Flibotte S, et al. An NMR determination of the physiological water distribution in wood during drying[J]. J Appl Polym Sci, 1987, 33(4): 1 141-1 155

[18] Menon R S, Mackay A L, Flibotte S, et al. Quantitative separation of NMR images of water in wood on the basis of T₂[J]. J Magn Reson, 1989, 82(1): 205-210.

[19] Shao Zhu-wei(邵朱伟), Zhang Ming-hui(张明辉), Li Xin-yu(李新宇). Curing process of urea-formaldehyde resin studied by time-domain nuclear magnetic resonance(利用时域核磁共振研究脲醛树脂的固化过程)[J]. Chinese J Magn Reson (波谱学杂志), 2014, 31(3): 372-380.

[20] Wang Zhi-zhan(王志战), Wei Yang-xu(魏杨旭), Qin Li-ming(秦黎明), et al. Oil layer identification by NMR with the use of oil-based drilling fluid(油基钻井液条件下油层的NMR判识方法)[J]. Chinese J Magn Reson(波谱学杂志), 2015, 32(3): 470-480.

[21] Huang Gui-kun(黄桂坤), Qiu Li(邱莉), Jiao Yang(焦杨), et al. NMR assignments of two minor ginsenosides extratced from Panax notoginseng (Burk.) F. H. Chen(三七中2个微量人参皂苷的NMR信号全归属)[J]. Chinese J Magn Reson (波谱学杂志), 2014, 31(3): 415-425.

[22] Xu Y, Araujo C D, Mackay A L, et al. Proton spin-lattice relaxation in wood: T₁ related to local specific gravity using a fastexchange model[J]. J Magn Reson, 1996, 110(1): 55-64.

[23] Nanassy A J. Use of wide line NMR for measurement of moisture content in wood[J]. Wood Sci, 1973, 5(3): 187-193.

[24] Araujo C D, MacKay A L, Hailey J R T, et al. Proton magnetic resonance techniques for characterization of water in wood: Application to white spruce[J]. Wood Sci Technol, 1992, 26: 101-113.

[25] Maks Merela, Primoz Oven, Igor Sersa, et al, A single point NMR method for an instantaneous determination of the moisture content of wood[J]. Holzforschung, 2009, 63(3): 348-351.

[26] Sharp A R, Riggin M T, Kaiser R, et al. Determination of moisture content of wood by pulsed nuclear magnetic resonance[J]. Wood Fiber, 1978, 10(2): 74-81.

[27] Hui Fang(慧芳). Layered Multi-exponential Inversion Method Research of Magnetic Resonance Sounding Data(核磁共振地下水探测信号分层多指数反演方法研究)[D]. Jilin(吉林): Jilin University(吉林大学), 2013.

[28] Yao Feng-Ying(姚风英). NMR evaluation of reservoir damage caused by fracturing liquid on low permeable reservoir(低渗透储层压裂液伤害核磁共振评价方法)[J]. Petroleum Geology and Recovery Efficiency(油气地质与采收率), 2011, 18(2): 102-104.

[29] Shao Xiao-long(邵小龙), Zhu Jiang-wei(朱将伟), Li Yun-fei(李云飞). Statistical analysis for low-field nuclear magnetic resonance batch data of sweet corn(批量甜玉米低场核磁共振数据的统计分析)[J]. Journal of Shanghai Jiaotong University(上海交通大学学报), 2011(1): 144-148.

[30] Feng Jin(冯进), Sun You(孙友). A method to determine T₂ cutoff value in nuclear magnetic resonance log(核磁共振测井T₂截止值的确定方法)[J]. China Offshore Oil and Gas(中国海上油气), 2008, 20(3): 181-183.

[31] Chau Han S S, Aggarwal P, Karmarkar A, et al. Moisture adsorption behaviour of esterified rubber wood (Hevea brasiliensis)[J]. Eur J Wood Prod, 2001, 59(4): 250-253.

[32] Stamm A J. Wood and Cellulose Science[M]. New York: Ronald Press, 1964.