远红外木材干燥机理的研究

A Preliminary Study on wood Drying Throuth Far Infrared

福建22种常见树种木材远红外吸收光谱相似,在波数1840cm^（-1）附近均有个最强的透射峰。对22种木材进行远红外穿透深度测定,最大的是山槐弦向0.71mm;最小的是罗木石楠径向,0.135mm。弦向大于径向,且与木材密度、含水率等有关。木材对远红外吸收遵守朗伯定律,但吸收系数径向比弦向大。本文根据木材的远红外光谱图分析,提出木材纤维素、木素对远红外吸收,主要是分子含氧基团等键链间的振动吸收。根据远红外对木材的穿透深度,并通过热导方程分析、计算,认为厚度2mm以下薄板内部形成“正热源”是可能的。这为远红外木材干燥提供了科学依据。

The analysis of far infrared spectra of 22 major tree species of Fujian shows that the far infrared radiation wave number which caused the maximum depth of penetration in wood, was around 1840 cm-1. Having measured the depth of far infrared penetration of 22 tree species, we learnt that the maximum one was 0.71mm in the tangential section of 'Albizzia kalfora', and the minimum one was 0.135mm in the radial section of 'Photinia davidso-ma', and that the penetration was deeper in tangential section than in radail section and it varied with the density and moisture content of wood, and the .aw of wood absorbing the far infrared radiation corresponded with the Lambert's absofption law, but the coefficient of absorption was larger in radial section than in tangential section. In the light of far infrared spectra, we put forward that the absorption of far infrared in the cellulose and lignin is mainly caused by the viberation of the equivelent chain of molecular Oxygenic Group, and that, based on the calculation by Heat Conduct Equation, the formation of 'Positive Heat Source' inside the 2mm-thick sheet of wood is possible when radiated on two sides by perpendicular far infrared ray, thus providing scientific basis for far infrared drying.