Abstract:

To improve the comprehensive utilization efficiency of microalgae, dry or wet Nannochloropsis were extracted with different solvent and hydrothermal liquefaction (HTL) experiments of defatted Nannochloropsis were carried out to explore the effects of defatted methods on HTL products. The solvent extraction results showed that polar solvent can extract 25.0% of lipids from microalgae without selectivity, which resulted in only 29.68% for the fatty acid methyl ester yield of the extracts; the fatty acid methyl ester recovery of mix solvent was 57.70%. For the HTL bio-crude of defatted Nannochloropsis, the yield was 27.7%—34.6%, nitrogen content was 5.29%—6.68%, mainly consisted of fatty acid, fatty acid esters, fatty acid amides, long-chain hydrocarbon, amines, oxygen-containing compounds and nitrogen-containing heterocyclic compounds. The yield of wet algae hydrothermal crude oil after methanol extraction was 34.6%, the nitrogen content was 5.44%, and the process energy consumption was low, indicating that methanol extraction wet algae combined with hydrothermal liquefaction has certain application prospects.

Key words: microalgae, lipids extraction, fatty acid methyl ester, hydrothermal liquefaction, bio-crude

摘要：

为提高微藻的综合利用效率，使用不同的溶剂系统分别对干、湿微拟球藻进行油脂萃取，并对脱脂后的藻渣进行水热液化实验，探究溶剂萃取脱脂对微藻水热液化产物的影响。溶剂萃取的结果表明，极性溶剂对油脂的萃取率达到25.0%，但对脂质的萃取缺乏选择，萃取物的脂肪酸甲酯产率仅为29.68%；混合溶剂萃取的脂肪酸甲酯回收率达到57.70%。脱脂后的微拟球藻水热粗油产率为27.7%~34.6%，氮含量为5.29%~6.68%，主要由脂肪酸、脂肪酸酯、脂肪酸酰胺、长链烃类、胺类、含氧化合物和含氮杂环化合物组成。经甲醇萃取后的湿藻水热粗油产率为34.6%，氮含量为5.44%，过程能耗低，表明甲醇萃取湿藻结合水热液化具有一定的应用前景。

关键词: 微藻, 油脂萃取, 脂肪酸甲酯, 水热液化, 水热粗油