使用了两步加氢-超临界提质以及一步超临界提质两种方法对生物油进行提质，并进行了溶剂回收利用。实验结果表明经过这两种提质方法，生物油的物化性质均得到有效提升，提质后生物油中酸、酮和酚的相对含量明显下降，而醇、醚和酯类等理想产物的相对含量有显著上升。根据每步产物的GC-MS结果，对提质过程中所发生的反应进行了推测。相对于一步法提质所得到生物油，两步提质法所得到的提质生物油中醇和醚类的相对含量略高而酮、酚和酯类的相对含量略低。同时，相比于一步超临界提质，两步加氢-超临界提质过程中乙醇的消耗量有所降低。溶剂的回收利用在降低生物油提质所需要的乙醇含量的同时提高了提质产物中酯类的相对含量，这表明在较低的醇油比条件下超临界提质仍然是一种有效的生物油提质方法。%To upgrade bio-oil,two upgrading methods were employed:low temperature hydrogenation (175℃) followed by supercritical upgrading in ethanol (HS),and direct upgrading in supercritical ethanol (DS). By both methods,the physical properties (heating value,pH) of bio-oil were improved greatly. Besides,the relative content of acids,ketones,and phenols decreased significantly while that of alcohols/ethers and esters increased dramatically after upgrading. The reactions occurred in each step were tentatively discussed based on GC-MS results. Compared with the upgraded bio-oil from DS,the relative content of alcohols/ethers was higher in that from HS,while the relative content of ketones,phenols,and esters showed an opposite result. The consumption of ethanol was lower in HS. The recovery of ethanol by rotary evaporation and reutilization of the recovered ethanol not only reduced the consumption of ethanol,but also increased the relative content of esters in the upgraded bio-oil. These results indicated that bio-oil could be effectively upgraded by supercritical upgrading at relatively low ratios of ethanol to bio-oil.
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