改良直接轉酯化反應轉化微藻為生質柴油

Biodiesel Production from Microalgae by the Modified Direct Transesterification

古鎬綱(Hao-Kang Ku)

指導教授 ： 劉懷勝

國立臺灣大學/工學院/化學工程學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.00167

摘要

微藻是一種能行使光合作用之單細胞植物，能快速生長且累積大量油脂於微藻細胞中，因此微藻被認為是有潛力的生質燃料來源。但由於微藻的收集與油脂萃取不易導致能量成本高，以至於目前微藻轉化之生質柴油仍難有商業價值。為使生產生質柴油更有效率，設計適當微藻轉化為生質能源的程序乃是重要之課題。

本研究所使用之微藻為水體中常見之小球藻(Chlorella sp.)。以直接轉酯化反應將微藻轉化為脂肪酸甲酯，此程序合併萃取與酯化步驟，直接反應為一種將已皂化之油脂轉化為脂肪酸甲酯的方法，其產物即為生質柴油，也可直接藉由氣相層析儀分析(GC)。實驗結果顯示，藉由直接轉酯化反應，最終脂肪酸甲酯總量比傳統兩步驟萃取酯化反應多出約26%，且所需反應程序時間也縮短為傳統製程的二十分之一。此外，經本研究改良後之直接轉酯化反應，並不需要具有高毒性的三氟化硼作為反應之催化劑、物理性細胞破碎法，如超音波細胞破碎儀，也可以從程序中移除。藉由適當調整反應之酸鹼當量濃度，可得一最佳脂肪酸甲酯總產量。另外，於第一階段皂化反應的步驟，經調控反應溫度由100°C降至80°C，依然可以獲得相同之脂肪酸甲酯總產量。

關鍵字:微藻、小球藻、微藻油脂、脂肪酸甲酯、生質柴油、直接轉酯化反應

關鍵字

微藻 ； 小球藻 ； 微藻油脂 ； 脂肪酸甲酯 ； 生質柴油 ； 直接轉酯化反應

並列摘要

Microalgae, a photosynthetic organism, can not only grow fast but also accumulate lipid in microalgal cells. Therefore, microalgae are considered as a potential source of biofuel. However, this potential has yet been realized because of some technical barriers, such as harvest of algae, and high energy requirements of extraction of lipid. In order to produce biofuel by microalgae efficiently, it is important to seek a better process to convert lipid into biodiesel.

In this study, Chlorella sp. was used as the source of biodiesel production. Direct transesterification (DT) is a method of converting saponifiable lipids directly to fatty acid methyl esters (FAME) which can be quantified by gas chromatography (GC). DT, by combining the extraction step, resulted in 26% increase of productivity of fatty acid methyl ester and about 1/20 times of reaction time, compared to the conventional extraction- transesterification method. In addition, acidic catalyst, boron trifluoride (BF3), and cell disruption were not necessary via the modified DT in the study. With a proper ratio of acid and base, it was found that there was an optimal total productivity of FAME. Furthermore, as the reaction temperature decreased from 100°C to 80°C, the productivites of FAME were the same.

Keywords: Microalgae, Chlorella sp., Microalgal lipid, Fatty acid methyl ester, Biodiesel, Direct transesterification

並列關鍵字

Microalgae ； Chlorella sp. ； Microalgal lipid ； Fatty acid methyl ester ； Biodiesel ； Direct transesterification

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