超临界CO2流体干燥海洋出水木质文物的实验研究

Experimental research on supercritical CO2 fluid drying for water-saturated wooden relics

有研究表明,相较于传统的干燥技术,利用超临界CO2流体干燥技术对出土饱水竹木器进行干燥具有周期短、变形小的优势。与出土饱水竹木器相比,海洋出水木质文物除了含水率高外,还含有较多的难溶性盐分,在文物的长期保存和展览中,盐分与水分、空气、文物本身进行化学反应会加速文物的老化和腐蚀。因此,本研究以“南海Ⅰ号”船体的部分构件为研究对象,开展了将超临界CO2流体干燥技术应用于海洋出水木质文物的探索实验研究。实验结果表明,在温度40℃,压力20 MPa的条件下,超临界CO2流体干燥海洋出水木质文物效果明显,样品的三向干缩率均低于或者接近健康木材阴干的三向干缩率;含水率大幅度下降,经过超临界技术干燥后不需再做其他干燥处理就能满足文物保存的要求。文物干燥前后含盐率的测量结果表明,此干燥技术还具有明显脱盐的效果。

Some studies have shown that compared with traditional drying technologies,supercritical CO2 technology has some advantages,such as a shorter drying time,smaller deformation,etc.Compared with unearthed waterlogged bamboo and wood wares,undersea wooden cultural relics contain more insoluble salts.In the case of long-term preservation and exhibition of cultural relics,the chemical reactions of salts with water,air or the cultural relics themselves will accelerate the aging and corrosion of the cultural relics.In this research,some components from NanhaiⅠshipwreck were taken as the research objects.The experimental results show that under the conditions of 40℃and 20 MPa,the effect of supercritical CO2 fluid drying on the undersea wooden cultural relics was obvious in that the three-dimensional shrinkage of the samples was lower than or close to those of the healthy wood.After drying,the water content met the requirements of cultural relic preservation and the salt content of the samples also decreased significantly.