Abstract:

In order to explore the optimal process conditions for producing bio-oil from waste tobacco leaves treated with near-critical water, a single factor experimental design was used to investigate the effects of reaction temperature, solid-liquid ratio and holding time on the bio-oil yield of tobacco leaves. The technology conditions of near-critical water treatment of waste tobacco were optimized by orthogonal experiment. The results showed that the optimal treatment combination was 260℃, solid-liquid ratio 4∶50 and holding time 15min. Under these conditions, the yield of tobacco leaf bio-oil was 57.68%. The composition of water-soluble oil and residual oil was characterized by GC-MS analysis. The results showed that a total of 69 chemical components were isolated under the optimal extraction process conditions, mainly phenols, accounting for 49.39% of the total, followed by heterocycles, accounting for 25.69% of the total; a total of 37 chemical components were isolated from the residual oil, mainly esters and heterocycles, accounting for 25.66% and 20.21% of the total oil, respectively. This method follows the concept of green extraction, uses water as solvent, and is environmentally friendly. Compared with traditional extraction methods, this method has high yield of bio-oil and rich aroma components, which provides a new way for the treatment of waste tobacco leaves.

Key words: near-critical water, waste tobacco leaves, bio-oil, aroma components, orthogonal test

摘要：

为了探究近临界水处理废次烟叶制备生物油的最佳工艺条件，本文采用单因素试验设计，考察反应温度、固液比、保温时间对烟叶生物油产率的影响，并通过正交试验，对近临界水处理废次烟叶的工艺条件进行优化。结果表明：近临界水液化烟叶的最佳处理组合为反应温度260℃，保温时间15min，固液比4∶50，此条件下烟叶生物油产率为57.68%。使用GC-MS（气相色谱-质谱联用仪）分析对水溶性油和残渣油的成分进行表征，结果显示，在最佳提取工艺条件下，从水溶性油中共分离出69种化学成分，以酚类为主，占总量的49.39%，其次为杂环类，占总量的25.69%；从残渣油中共分离出37种化学成分，以酯类、酮类为主，分别占总量的25.66%、20.21%。本方法遵循绿色提取理念，以水为溶剂，对环境友好，与传统提取方法相比，生物油产率高，致香成分丰富，为废次烟叶处理提供了新的途径。

关键词: 近临界水, 废次烟叶, 生物油, 致香成分, 正交试验