200 m^(3)透明质酸生物反应器的流场模拟

Flow field simulation of a 200 m^(3)hyaluronic acid bioreactor

随着透明质酸市场规模不断扩大,发酵生产透明质酸产量日益增多,为了对大型透明质酸生物反应器的放大设计提供理论依据,该文将透明质酸发酵液视为非牛顿流体,使用剪切应力输运模型对200 m^(3)生物反应器中不同搅拌器组合下的流场进行模拟建模。计算结果表明,使用斜叶桨式搅拌器流速最低,功耗最低,三折叶桨式搅拌器流速最高,流体流动性增强效果最好,功耗最高;弧叶圆盘涡轮搅拌器流体流速分布好于直叶圆盘涡轮搅拌器,功耗更低,更适合作为发酵罐底桨。综合流场分布,表观黏度分布以及轴功率数据考虑,选定最佳桨叶组合为三层三折叶桨式搅拌器+弧叶圆盘涡轮搅拌器进行发酵试生产,经过24 h发酵,透明质酸产率达到12.53 g/L。为工业高黏物料生物反应器放大设计提供了思路。

As the market scale of hyaluronic acid continues to expand,the production of hyaluronic acid through fermentation has increased.In order to provide a theoretical basis for the scaled-up design of large-scale hyaluronic acid bioreactors,hyaluronic acid fermentation broth is considered as a non-Newtonian fluid and shear stress transport model is used to simulate the flow field under different agitator combinations in a 200 m^(3)bioreactor.The computational results indicate that the paddle impeller with pitched-blades has the lowest flow velocity and power consumption,the paddle impeller with three folded blades has the highest flow velocity and the best enhancement of fluid flowability but also the highest power consumption.The disc turbine impeller with arc type blades exhibits better fluid flow distribution than that with straight blades,with lower power consumption,making it more suitable as a bottom impeller in fermentation tanks.Considering the overall flow field distribution,apparent viscosity distribution,and shaft power data,the optimal impeller combination is determined as three paddle impellers with three folded blades plus a disc turbine impeller with arc type blades,and this combination was tested for fermentation production.After 24 hours of fermentation,the yield of hyaluronic acid reached 12.53 g/L.The insights for the scaled-up design of industrial bioreactors handling high-viscosity materials is provided.