微藻油脂制备生物柴油的研究

STUDY ON PREPARATION OF BIODIESEL FROM MICROALGAL OIL

利用正己烷从异养生长的小球藻(脂类化合物含量高达细胞干重的55%,是自养藻细胞(14%)的4倍)细胞中提取获得了大量油脂。这些异养微藻油脂在30℃、醇油物质的量比为56∶1以及浓硫酸催化条件下经酯交换反应4h可形成高质量的生物柴油。微藻生物柴油的密度为0.864kg.L-1、粘度5.2×10-4(40℃)、热值高达41MJ.kg-1。这些特征与传统柴油相当,且微藻生物柴油具有更低的冷滤点(-11℃)及良好的发动机低温启动性能,因此其应用价值更高。

Biodiesel fuels have received considerable attention in recent years as a renewable, biodegradable, and nontoxic fuel. Chlorella pmtothecoides is a microalgae that can be photoautotrophically or heterotrophically grown under different regetal conditions. Hetemtmphic growth of Chlorella pmtothecoides resulted in the accumulation of high lipid content of 55% in ceils, which was about 4 times that in autotrophic cells （ 14% ）. Large amount of microalgal oil was efficiently extracted from these heterotrophic cells by using n-hexane. Good quality of biodiesel was obtained from hetemtmphic micmalagl oil under the conditions of acid catalyst with 56：1 molar ratio of methanol to oil at temperature of 30℃ in about 4h of reaction time. The biodiesel was characterized by a density of 0.864 kg/L, the viscosity of 5.2 × 10^-4 （40℃） and a heating value of 41 MJ kg^-1. These properties are comparable to conventional diesel. The biodiesel from microalgal oil showed much lower cold filter plugging point of - 11 ℃ in comparison with the diesel fuel, which is better for engine start at lower temperature. Developing high lipid content microalgae or ＇ bioengineering microalgae＇ would be a new and the main way for biodiesel production in the future.