生物质热解制备木醋液及其性质研究

对杉木屑、棉杆、竹屑三种生物质热解制得的木醋液产率、基本理化性质及其有机成分进行了分析研究。结果表明,三种生物质原料在350℃下热解制得的粗木醋液、精制木醋液产率相差不大,相同条件下氯化钾浸渍处理后的杉木屑热解所得的粗木醋液、精制木醋液的产率有所降低。三种原料制得的精制木醋液的理化性质不同,杉木屑木醋液的pH值最小,密度最大,竹屑和棉杆木醋液的有机酸含量相对较高。采用GC-MS对精制木醋液中的有机成分进行了分析,结果表明,杉木屑木醋液中的主要组分为酸类、酚类和酮类化合物,棉杆和竹屑木醋液中的主要组分除这三类有机物质外,还含有相对含量较高的醇类化合物。酸类和酚类化合物在三种木醋液中的相对含量依次是竹屑 >棉杆 >木屑;酮类的相对含量依次是木屑 >棉杆 >竹屑。氯化钾处理后的木屑热解所得的木醋液中主要组分酚类和酮类化合物的相对含量有所降低,酸类化合物的相对含量增加,主要表现为乙酸相对含量的增加。与杉木屑木醋液相比,KCl处理后的杉木屑木醋液中的醇类化合物相对含量增加了1倍左右。

Wood vinegar and its properties from pyrolysis of biomass

The basic physical and chemical properties, yields and organic ingredients of the refined wood vinegar obtained from pyrolysis of Chinese fir sawdust (CFS), cotton stalk (CS) and bamboo sawdust (BS) were investigated. The results show that yields of crude wood vinegar and the refined one from the three biomasses at 350℃ are nearly the same. However, yield of the wood vinegar from KCl-treated CFS (KCl-CFS) under the same conditions decreases. The physical and chemical properties of the three refined wood vinegars are different from each other. The pH value of CFS wood vinegar is the lowest and its density is the highest. The content of the organic acids contained from BS and CS wood vinegars is higher than that of CFS wood vinegar. The organic components in the refined wood vinegars were analyzed by gas chromatography and mass spectrometry (GC-MS). The results indicate that CFS wood vinegar includes acids, phenols and ketones. Besides the three ingredients, alcohols with high relative content are found in BS and CS wood vinegars. The relative contents of the acids and phenols contained in the three wood vinegars are in the order of BS > CS > CFS and that of the ketones is CFS > CS > BS. The relative contents of the phenols and ketones contained in the refined wood vinegar produced from KCl-CFS decrease and that of the acids increases, especially the acetic acid. The relative content of the alcohols contained in the refined KCl-CFS wood vinegar roughly doubles compared with that of CFS wood vinegar.