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.