| As an important type of biomass, algae attracted increasing attentions for its fast growth rate, good adaption to environment, and high photosynthesis efficiency. In this thesis, we selected microalgae(Spirulina platensis(SP) and Chlorella pyrenoidosa(CP)) and macroalgae(Entermorpha prolifera(EP)) as raw materials to investigate their thermal-chemical reaction activities and optimize reaction parameters. Main research contents and results are listed as follows:Firstly, co-liquefaction of microalgae SP and macroalgae EP was performed in sub-critical water under different conditions. The results suggested that a positive synergetic effect existed during the co-liquefaction. Co-liquefaction alleviated severe reaction conditions compared to the separate liquefaction of SP and EP and also promoted in situ deoxygenation of the bio-oil.Secondly, different types of solvent with different polarity were applied in the liquefaction of CP to screen how solvent polarity affects its liquefaction behavior. Increasing solvent polarity increased the conversion of algae. Ethanol was identified as the most suitable solvent for conversion of microalgae. With employing ethanol as reaction medium, influences of reaction temperature, time, and algae to ethanol ratio on products distribution and properties of bio-oil were determined.Thirdly, liquefaction behavior of CP in acetone was examined to maximize bio-oil yield. Under optimal conditions, the highest bio-oil yield was 78.9 wt.%. The most abundant compounds of bio-oil are unsaturated fatty acids and hydrocarbons.Finally, activities of several different Lewis acid catalysts were examined to identify the most suitable catalyst for crude biodiesel(CBD) production. Of those catalysts tested, Zn Cl2 showed the highest performance. Using Zn Cl2 as catalyst, effects of reaction conditions on product distribution and properties of CBD were studied. The results suggested that moisture is the most influential factor affecting yield and properties of CBD. |
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