Experimental Study On Cyanobacteria Thermochemical Liquefaction

The biomass is the fourth largest energy. As the only clean renewable energy source, Biomass has been produced gas, liquid and solid directly, research biomass energy has become an important task at home and abroad. Many studies on biomass hydrothermal liquefaction have been carried out to meet the energy demand recent years at home and abroad, and a lot of research techniques have also been mainly perfect. There are a lot of research about exploration of the liquefaction mechanism, selection of the catalyst and improving the liquefaction efficiency, but seldom using microalgae for liquefied raw materials, especially cyanobacteria. Cyanobacteria biomass is mainly composed of proteins, lipids and polysaccharides, which is different from lignocellulose. So it is necessary to study the hydrothermal liquefaction of the cyanobacteria. The research can provide some theoretical guidance and open up a new realm for our agriculture aspect. It also provides chances to look for a renewable resources instead of petroleum resources, which will reduce pollution of environment.The experimental research on thermo chemical liquefaction of cyanobacteria was carried out, main contents as follows:1. Catalytic liquefaction of the cyanobacteria in supercritical ethanol was carried out in an5ml autoclave. During the tentative experiment, the influences of reaction temperature, reaction time, catalyzer loading, were investigated. The results showed that the optimal conditions are reaction temperature270℃, reaction time40min, the concentration of catalyzer SO42-/ZrO22%, ratio of cyanobacteria to ethanol1:15g/ml. Under these conditions, the liquefaction conversion rate reaches87.46%and the yield of bio-oil is63.32%.2. Catalytic liquefaction of the cyanobacteria in solvent mixtures of ethanol and water was carried out in an5ml autoclave. The results showed that the optimal conditions are reaction temperature290℃, reaction time20min, the concentration of catalyzer SO42-/ZrO24%, ratio of cyanobacteria to ethanol1:15g/ml. Under these conditions, the yield of bio-oil is the best. Orthogonal experimental study of ethanol-water mixture (20%), the results showed that the optimal conditions are reaction temperature280℃, reaction time10min, the concentration of catalyzer SO42-/ZrO26%, ratio of cyanobacteria to ethanol1:20g/ml. Under these conditions, the yield of bio-oil is56.72%.3. The kinetic analysis was performed by using a composite procedure involving the model method. Direct liquefaction of the cyanobacteria supercritical ethanol was carried out in an5ml autoclave. Direct liquefaction of the cyanobacteria in supercritical ethanol was carried out in an5ml autoclave. The kinetics calculation indicates that the apparent activation energy is50.793kJ/mol, and frequency factor with3437.16. Catalytic liquefaction of the cyanobacteria in supercritical ethanol was carried out in an5ml autoclave. The kinetics calculation indicates that the apparent activation energy is47.74kJ/mol, and frequency factor with2079.4. The cyanobacteria was analyzed by FT-IR and elemental analysis, the oil was analyzed by elemental analysis, FT-IR analysis and GC-MS, the solid residue was analyzed by FT-IR. The conclusions as follows:a. The main conclusions were obtained by calculation:the molecular of cyanobacteria is CH0.46O1.83N0.19, high calorific value of20.32MJ/kg; the molecular of oil a is CH0.13O1.56N0.13, high calorific value of30.38MJ/kg; the molecular of oil a is CH0.15O1.41N0.14, high calorific value is28.61MJ/kg.b. The oil contains alcohols, phenols, aldehyde, ketone and aliphatic compounds.c. Compared with cyanobacteria FT-IR and the solid residue FT-IR, can be inferred that functional groups have broken, such as N-H, C-H, C=O and C=C.