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Investigation on lipid extraction of microalgae assisted by microwave and ultrasound
|Authors: ||Bo-Yu Lin|
|Contributors: ||NTOU:Department of Marine Engineering|
Microwave-assisted extraction;ultrasound-assisted extraction;crude microalgae lipid;fatty acids
|Issue Date: ||2011-11-25T07:10:30Z
|Abstract: ||本研究利用超音波與微波打破藻體細胞壁，以萃取藻胞內的油脂，比較超音波與微波在不同溶劑、時間與功率下的粗油脂萃取率，也探討乳化溶劑對於粗油脂萃取率的影響。將Isochrysis galbana (等鞭金藻)藻粉利用不同溶劑進行微波萃取與超音波萃取粗油脂後進行脂肪酸、元素分析、甲基酯等特性分析比較，結果顯示利用微波萃取微藻體油脂以正己烷/異丙醇(2:1 v/v)溶劑有最高的粗油脂產率達10.87 wt.%；利用超音波以異丙醇溶劑萃取粗油脂時的產率最高為10.45 wt.%，另外乳化正己烷與異丙醇相較於直接混合同樣兩種溶劑有較高的油脂產率，但後者的油脂萃取產率有較平穩上升趨勢。另外將Isochrysis galbana (等鞭金藻)收集後直接轉酯化與萃取粗油脂後轉酯化和市售(廢食用油)生質柴油等三種脂肪酸分析比較後，發現在萃取粗油脂之後再行轉酯化的飽和脂肪酸較高，也有較高的油品的安定性、運動黏度及十六烷值，但碘價相對較低，長碳鏈脂肪酸(C20~C22)含量比以廢食用油所製備的生質柴油高，熱值也較高。|
Supersound and microwave were used to assist the lipid extraction of microalgae by solvents in this study. Crude lipid extracted quantity between the supersound and microwave-assisted lipid extraction under various solvents, extracting time and power were compared. The effect of emulsified solvent on the crude lipid extraction ratio was studied as well. The experimental results show that Isochrysis galbana extracted by microwave using the solvent mixture of n-heptane and iso-propanol in 2:1 volumetric ratio had the largest extracted quantity of crude microalgae lipid which is 10.87 wt. %. The extracted quantity of the crude lipid of Isochrysis galbana is the largest, 10.45 wt. % when ultrasound-assisted extraction was used together with iso-propanol solvent. In addition, the Isochysis galbana extracted by microwave using the emulsion of n-hexane and iso-proanol had higher lipid extracted quantity than that using the mixture of the same two solvents, while the extracted lipid by the latter solvent mixture appeared linear increase with the input energy of microwave. The fatty acid compositions of Isochrysis galbana which were transesterified from crude lipid was compared with those directly from the microalgae powder and those of commercial biodiesel from waste cooking-oil. It was found that the fatty acid methyl esters from transesterification of crude microalgae lipid had higher saturated fatty acid, higher oxidative stability, kinematic viscosity and calculated cetane number while lower calculated iodine value than those from the microalgae powder. In contrast, the biodiesel from waste cooking oil had the highest fatty acids of long carbon chain and heating value among IV those three biodiesels.
|Appears in Collections:||[輪機工程學系] 博碩士論文|
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