Preparation Of Microalgae Oil And Study On Extraction Of Microalgal Oil With Subcritical Fluid Ethanol

Biodiesel is the international fastest growing renewable energy,with low Nitrogen and sulfur content,and the characteristics of less pollution release during combustion process.Microalgae are widely distributed on Earth,with high fat content,high proliferation rate,and high energy conversion efficiency,it can be used as an important raw material for biodiesel production.However,due to its high production costs,microalgae biodiesel is still in the initial stage of development.In this study,from the point of view of solving problems of the low yield of existing biodiesel materials,the low yield and low energy consumption of microalgae bio oil production methods,the issue encountered in the preparation of microalgae oil and the preparation of bio oil were studied.First,the factors affecting the preparation of microalgae raw materials such as carbon source,nitrogen source,phosphorous source and light were optimized and to prepare the microalgae raw materials,which dry biomass was about 2.1 g/L,the oil content was about 22% and the oil yield was about 0.41 g/L.The raw materials of microalgae were harvested by electric coagulation.The effects of ultrasonic,freeze-thawing and acid-heated on the disruption treatment of microalgae oil were studied.The oil extraction of microalgae was carried out on the basis of the microalgae raw material with high liqids yield.The optimum condition of subcritical fluid method was obtained by single factor experiment and orthogonal test.The optimum conditions were as follows: ethanol as solvent,n-hexane as co-solvent,solvent co-solvent volume ratio of 6: 1,temperature of reaction 240 ?,residence time of 30 min,material ratio of 1:30.Under these conditions,the bio oil yield of microalgae was 72.6%.The biological properties of the obtained microalgae were analyzed.The bio oil had good combustion performance and was clean and environmental friendly as well,similar to diesel,and had good application value.The feasibility of the dry and wet preparation method of bio oil from microalgae was studied.It was found that the wet method of bio oil preparation with subcritical fluid from microalgae has high yield and low energy consumption,and has good application prospect.