Optimal Design For Inner-structure Of Flat-plate Photobioreactors Based On The CFD Technology

Microalgae is a high light utilization efficiency autotrophic unicellular, which distributed widely and rich in nutrition. It has a promising exploitation future in liquid fuel, food, cosmetics and human health industries. Photobioreactor(PBR) is a core equipment for microalgae cultivation, that is the key problem of microalgae cultivation industrialization. With the rise of microalgal biofuels research, it is urgent to exploit large scale, low cost, high efficiency PBRs. Flat-plate PBR has advantage in large illumination surface area,short optical path, covers an area of small, low energy consumption, easy large-scale up,become one of most potential PBRs in large scale-up culture.Firstly, the computational fluid dynamics (CFD) technology was used to optimize two types of15L Flat-plate PRBs. Based on the CFD Simulation Result to analysis the mixing of fluid and the light regime characteristic of microalgae in the PBRs and obtain the better PBRs. Secondly, through the photoautotrophic cultivation of Chlorella pyrenoidosa to validate the reliability of calculation results. Finally, the correlation analysis of photoinduction results of microalgae with parameters of mixing and light regime characteristic,and it provided a theoretical basis for optimizing and scaling up PBRs. The main contents and results are as follows(1) Optimize inner structure of A style flat-plate PBRs. Through analysis of fluid mixing effect and light regime characteristic parameters could obtained the best PBR that was H=72-78mm,0=15°,d=20mm,n=2(or3).(2) Optimize inner-structure of C style flat-plate PBRs. After Single factor experiment optimization, it obtained better inner-structure of C style flat-plate PBRs were W=22mm,H=88mm,d=20mm,n=4,no Segmented.(3) The calculation results of C style flat-plate PBRs were validated. The correlation analysis of photoautotrophic results of Chlorella pyrenoidosa with mixing and light regime characteristic parameters indicated that the maximum cell concentration and specific growth rate of microalgae were linear positive correlation with the axial mean velocity of fluid in riser, the axial and radial mean velocity of fluid in downcomer.and linear negative correlation with LDCT and STD of microalgal cell.