能源微藻采收及油脂提取技术

Technologies of Microalgal Harvesting and Lipid Extraction

微藻具有光合效率高、生长周期短、油含量高等特性,是一种极具前景的生物柴油大宗原料。藻体采收和油脂提取是决定微藻柴油生产成本的关键环节,此下游技术的改进对提高微藻产油的经济性意义重大。本文综述了国内外微藻培养液的浓缩采收方法,并对絮凝沉降、絮凝气浮、离心和过滤等方法的作用机制和采收效率进行比较;阐述了目前微藻油脂的提取技术,从操作条件和能量消耗角度分别对有机溶剂、超临界和亚临界法进行评价;特别介绍了一种同时实现微藻生长和油脂提取的新型微藻油脂原位萃取法;最后总结了微藻能源下游技术中存在的主要问题和今后的发展方向,为进一步提高微藻生物柴油经济性提出参考性意见。

Microalgae, with the merits of environmental adaptability, high photosynthetic efficiency and high lipid content, have become one of the most promising raw materials for bio-fuels production, especially for the biodiesel production. In this paper, the advances of technologies in microalgae harvesting and lipid extraction worldwide are reviewed. Firstly, several methods such as floeculation, centrifugation and filtration, as well as their mechanisms and applications for microalgae recovery are introduced. Then, the practical lipid extraction technologies including organic solvents, supereritieal and subcritical fluids are evaluated based on their operation conditions and energy consumption. In particular, a novel method of in-situ lipid milking is introduced to allow synchronous culture and lipid extraction of microalgae. Finally, the main problems within the downstream processing of algal oil are summarized and the possible solutions to produce cost-efficient algal biodiesel are proposed