Study Of Experiments In Heterotrophic And CFD Simulation Of Autotrophic-Raceway Pond Of Energy Microalgae Photo-bioreactor

The reactor structure of energy microalgae is studied through experiment and CFD to improve production efficiency. Based on experiments under gas-liquid two phases, impeller of energy microalgae reactor in heterotrophic culture is optimized. The result shows that the combination two six curved blade turbine and hydrofoil impeller is better than six curved blade turbine in oxygen mass transfer coefficient, which is improved by 14% under 1VVM,1KW/m3. Under gas liquid solid three phase, the former is better than the latter in oxygen mass transfer coefficient, which is improved by 7% under 1VVM,1KW/m3. Through CFD simulation, the former improves the flow field in the reactor and gas distribution between the two blades, makes oxygen mass transfer coefficient distribution uniform.In the open photo-bioreactor, raceway pond with liquid height of 300mm is best under the same volume power. By adding inner and outer guiding plate, the average speed of the raceway pond improves 17%, resistance coefficient decreases and velocity distribution is improved. In order to improve the vertical mixing, inclined boards are added in the raceway pond. It is best that the length of inclined boards is 0.5 times channel width and placed with 30 degree to the horizon. Velocity in Z direction is compared in raceway pond with none, before and after inlined board optimized. There is velocity in Z direction only on the corner of raceway pond with none. The velocity in Z direction is improved three times after inlined board optimized. Raceway pond with solid mass fraction 0.1% is simulated. Light intensity distribution curve is got through vertical distribution of solid volume fraction. The difference of light intensity between simulated and homogeneous value is small, so the raceway pond can be treated as homogeneous.One round pond with two blade fold impeller and the other with grid plate are simulated. Simulation of single-phase and solid-liquid two-phases shows that the former is better. The experiment results shows that the former is better in Chlorophyll content. In cell dry weight and lipid content, the experimental conditions is not satisfactory, so further experiment should be done.