Investigation On Extraction And Preparation Of Biodiesel From Microalgae Lipid

Biodiesel is a green, renewable, biodegradable fuel. Due to the diminishingpetroleum reserves and the environmental consequences of exhaust gases frompetroleum-fuelled engines, the application of biodiesel can relax our dependence ofpetroleum and phase down environmental pollution. Besides, the development ofbiodiesel is also a energy strategy of China. The main hurdle to the commercializationof biodiesel is the cost of feedstock and processing technique.In order to supply theoretical foundation to the industrialization of biodiesel，thispaper paid attention on the optimization of manufacturing biodiesel technique frommicroalgae lipid and properties detection of biodiesel，including microalgae cell wallbroken and lipid extraction，optimizing the best decoloration way，improving theproduction of biodiesel, detecting contents and chemical and physical properties ofmicroalgae biodiesel.1. In this study，chlorella is raw material, cell wall broken rate of microalgae isan indicator by comparing the ultrasonic method, high-speed homogenization,repeated freezing and thawing method, swelling method, microwave broken and acidheating method impact on cell disruption, I have found ultrasonic method was thebest for chlorella, its broken effect is significantly higher than other broken chlorellacells methods after12min, fragmentation rate can reach80.57%.2. Extraction microalgae lipid after pretreatment of chlorella byultrasound-assisted broken, the highest lipid yield is reached by utilizing thedichloromethane-methanol (2:1) as extraction solvent at40℃for6h，lipid yield canreach24.11%.3. Determined the species and compositions of fatty acid in microalgae lipidusing GC/MS. The result showed microalgae lipid were mainly constituted by C16toC20fatty acid， Hexadecenoic acid and Hexadecenoic acid are the highestcomposition,24.88%and24.1%respectively. The ratio of unsaturated fatty acid EPAis18.45%. 4. Decolorization process of microalgae oil is discussed by comparingdecolorization rate., and optimizing the decolorization process using orthogonaldesign. Under the optimum conditions, activated carbon is utilizing as decoloringagent at50℃for30min, adsorbent dosage heavy to oil5%, decolorization rate canreach52.73%.5.Biodiesel was prepared from microalgae oil through methyl esterificationreaction with methanol and lipase as catalysis. The result showed that the optimumcondition of LVK-H900lipase were: ratio of methanol to oil25:1,temperature60℃,time4h and enzyme dosage10%，biodiesel yeild could reach70.46%. In thereaction system of microalgae oil, LVK-H900lipase has a better catalyzed effect thanNovozym435lipase as a whole.6. Determined the species and compositions of fatty acid methyl ester inmicroalgae biodiesel using GC/MS and properties of microalgae biodiesel.Microalgae biodiesel contains several different kinds of fatty acid methyl esters, mostcontent of n-fatty acid methyl ester followed by Hexadecenoic acid methyl ester,Hexadecenoic acid methyl ester and Eicosapentaenoic acid methyl ester,20.87%, and15.64%respectively The properties of resulting biodiesel were measured, and it wasconfirmed to fulfill the standards of GB/T20828-2007.