Evaluation of lipid extractability after flash hydrolysis of algae
Evaluation of lipid extractability after flash hydrolysis of algae
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DOI：
10.1016/j.fuel.2018.03.044
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发表时间：
2018-07-15
期刊：
影响因子：
7.4
通讯作者：
Kumar, Sandeep
中科院分区：
文献类型：
--
作者：
Teymouri, Ali;Adams, Kameron J.;Kumar, Sandeep
微藻被认为是生产可再生液体运输燃料的有前途的原料；然而，从微藻中提取脂质用于下游加工到生物燃料是藻类生物炼油厂面临的重要挑战之一。这项工作旨在评估应用闪蒸水解（FH）作为一种无化学技术的潜力，以提高藻类生物质的脂质可提取性，并与微藻的水热液化（HTL）相结合，以提高生物原油的产量和燃料生产的特性。为此，在280℃和10 s的停留时间下，对三种不同的藻类（Scenedesmus sp., Nannochloropsis sp.和Chlorella vulgaris）进行了FH过程。在FH之后，除了富含营养物质的水解产物外，还回收了大约40%的固体，这些固体含有几乎所有的脂质（bbb90 wt%），称为生物燃料中间体（BI）。对每种藻类的脂质提取率进行了动力学研究，并对其脂质谱进行了分析。结果表明，FH工艺显著提高了油脂的提取率。对于所有三种藻类，BI的脂质产量均高于原料藻类。在正己烷溶剂萃取过程中，小球藻在前15分钟的脂质产率（52.3 +/- 0.8比10.7 +/- 0.9 wt%）是生藻的5倍以上。所有湿生微藻和Scenedesmus sp.的BI提取速率均为零级反应，而其他两种藻类的BI提取速率均为二级反应。脂肪酸谱的比较表明FH过程对饱和脂肪酸的贡献。脂质提取后，在350℃和1 h的条件下进行常规水热液化，比较普通小球藻的原料和BI的生物原油产量。结果表明，与生藻相比，FH后BI的生物原油产量和质量显著提高。FH工艺提高了油脂的回收率，缩短了提取时间，是一种可行的油脂提取方法。它与HTL的集成显著影响了生物原油的产量和燃料生产的特性。
Microalgae is identified as a promising feedstock for producing renewable liquid transportation fuels; however, lipids extraction from microalgae for downstream processing to biofuels is one of the important challenges for algal based biorefineries. This work aims at evaluating the potential of applying flash hydrolysis (FH) as a chemical-free technique to increase the lipids extractability of algal biomass as well as its integration with the hydrothermal liquefaction (HTL) of microalgae to enhance the biocrude yields and characteristics for fuel production. To this aim, the FH process was performed on three different algal species (Scenedesmus sp., Nannochloropsis sp., and Chlorella vulgaris) at 280 degrees C and 10 s of residence time. Following FH, in addition to the nutrients rich hydrolysate, approximately, 40 wt% of solids containing almost all (> 90 wt%) the lipids termed as biofuels intermediates (BI), were recovered. Kinetics study on lipids extractability from the BI and their lipid profile analyses were conducted for each algal species. The results showed that the FH process had significantly enhanced the lipids extractability. For all three algae species, lipid yields from BI were higher than that of the raw algae. Lipid yields of Chlorella vulgaris in the first 15 min were more than five times higher (52.3 +/- 0.8 vs. 10.7 +/- 0.9 wt%) than that of raw algae during n-hexane based solvent extraction. The kinetics of lipids extractability followed a zero-order reaction rate for all wet raw microalgae and the BI of Scenedesmus sp., while the BI recovered from the other two algal species were determined as a second-order reaction. Comparison of fatty acids profiles indicated the contribution of the FH process in saturating fatty acids. Subsequent to lipids extraction, a conventional hydrothermal liquefaction was performed at 350 degrees C and 1 h to compare the biocrude yields from raw versus BI of Chlorella vulgaris microalgae. The results showed that the biocrude yields from the BI and its quality was significantly enhanced post FH than that of raw algae. The FH process was proven to be a viable option for lipid extraction by increasing the extent of recovery and decreasing the extraction time. Its integration with HTL notably impact the biocrude yields and characteristics for fuel production.