| Dunaliella is a single-celled algae without a cell wall, which adapts to a wide range of salt, found in oceans and salt lake. Along with increasingly prominent problems on the shortage of fossil fuel and environment pollution prominent, Dunaliella has been widely used in the field of energy technology because it possesses many obvious comparative advantages, such as biomass fuel originating form it with good quality and high calorific value after biomass thermo-chemical conversion. However, there are many complex chemical products in the process of conversion, including gas, liquid and solid residue besides other chemicals.Research shows that furfural, formic acid and hydroxyacetone, commonly applied in food industry, medicament and chemical products, were included in fluid of Dunaliella thermo-chemical conversion but relative reports are still rare. Therefore, On the one hand, seeking suitable Metal Catalysts catalytic Hydrothermal Liquefaction of D. tertiolecta, Which widely promotes transformation of biochemical component of D. tertiolecta, to get more objective products. On the other hand, it is necessary to carry out the chemical purification, thereby providing sufficient raw materials consisting of colorants spices, stabilizers and preservatives for food industry with the purpose of improving the comprehensive utilization ratio of Dunaliella thermo-chemical conversion products and reducing the pollution of the environment. In order to realize efficient conversion of algae biomass and obtain purified chemicals used in food industry, this study mainly aimed to control thermo-chemical conversion process and filter catalysts, finally laying the foundation for the realization of the biomass high-valued utilization.In this paper, process control and further analysis, concerning preparation of bio-oil by hydrothermal Liquefaction, were studied. The main research content is as follows:(1)Supported metal catalysts were gained by the way of directly load metal acting carbon nanotubes as the carrier and then they were characterized by using XRD, XPS and Raman characterization methods. The results showed that Pt, Zr, Ni and Co were supported on carbon nanotubes in the form of metal Pt, Zr O2,metal Ni and Ni2O3 as well as metal Co, respectively. In addition, the introductions of the metals have changed the structure of carbon nanotubes and significantly promote the thermal stability of the catalyst.(2)Taking D. tertiolecta as raw material, bio-oil was prepared using supported metal catalysts, from the laboratory, by hydrothermal Liquefaction. And then, liquefied products were analyzed by thermogravimetric analysis, elemental analysis, FT-IR and GC-MS of liquefied products. The results proved that Metals added into metal catalysts, improving the quality of bio-oil result from, play a role of deoxidization hydrogenation in the process of hydrothermal liquefaction. Among these supported metal catalysts, Co/CNTs is the optimum one because of having the best conversion rate and oil production rate, which are were 95.78% and 40.25 wt. %, respectively.(3)Separation, purification and analysis was carried out on the preparation of crude bio-oil from hydrothermal liquefaction using column chromatography. Research results by means of IR, GC- MS and MS show that:, compared to the crude biological components being refined though column chromatography, are not only more clear but also the purity of them were improved obviously, whose product recovery was 91.38%. Key words: Bio-oil, Metal catalyst, product analysis, Column chromatography... |
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