不同蒸馏压力下的生物油分子蒸馏分离特性研究

Molecular distillation separation characteristic of bio-oil under different pressures

采用分子蒸馏分离技术对热敏性生物油在不同蒸馏压力下的分离特性进行了研究。经过分子蒸馏分离后,生物油被分离为蒸出馏分油与残留馏分油,蒸出馏分油的得率随着压力的下降而显著增大,在700 Pa时达到了56.50%(质量分数)。在馏分油的物理性质方面,蒸出馏分油富集了生物油内的大部分水分,残留馏分油内水分得到了较好的脱除,其中,700 Pa下残留馏分油的水分含量降至4.20%(质量分数)。结合生物油及馏分油的GC-MS分析结果,对乙酸、苯酚、糠醛以及左旋葡聚糖等生物油内典型化合物在不同蒸馏压力下的分布特性进行了研究,获得了相应化合物在分子蒸馏过程中的富集规律。结合分离因子评估模型对生物油内14种代表化合物的富集特性进行了量化评价。

The separation properties of sensitive bio-oil using molecular distillation technology were investigated under different distillation pressures. Crude bio-oil is divided into distillate fraction and residual fraction after the molecular distillation process. The yield of distillate fraction increases obviously with the decline of pressure, which achieves the highest value of 56.50% under 700 Pa. Most of water is enriched in the distillate fraction while water in residual fractions is effectively removed; water content in the residual fraction under 700 Pa is reduced to 4. 20%. The distribution of some typical compounds, including acetic acid, phenol, furfural, levoglucosan, etc, under different distillation pressures was studied and the separation characteristic of these typical compounds was obtained; based on that, a separation factor model was proposed and a quantitative evaluation was made on the enrichment behaviors of 14 compounds in bio-oil.