高粘发酵体系不同搅拌桨的CFD模拟及发酵验证

Computational fluid dynamics simulation of different impeller combinations in high viscosity fermentation and its application

摘要:

搅拌桨是高好氧高黏度微生物发酵实现高效反应必不可少的因素之一，不同搅拌桨组合对发酵过程的影响十分重要。威兰胶是由产碱杆菌在高耗氧高粘度发酵体系下合成的胞外微生物多糖，广泛应用于水泥、石油、油墨、食品等行业中。本研究借助于计算流体力学 (Computational fluid dynamics，CFD) 的方法，以威兰胶发酵液体系为研究体系，研究了6种不同搅拌桨组合在反应器内流体速率分布、剪切速率、和气含率等参数。将模拟效果较好的3种组合用于威兰胶发酵过程。研究表明MB-4-6搅拌桨组合对改善发酵罐内部的溶氧及流场分布效果最明显，威兰胶产量水平提高了13%。同时在该组合下威兰胶的产品粘度得到有效提高。

Abstract:

Agitator is one of the essential factors to realize high efficient fermentation for high aerobic and viscous microorganisms, and the influence of different impeller combination on the fermentation process is very important. Welan gum is a microbial exopolysaccharide produced by Alcaligenes sp. under high aerobic and high viscos conditions. Computational fluid dynamics (CFD) numerical simulation was used for analyzing the distribution of velocity, shear rate and gas holdup in the welan fermentation reactor under six different impeller combinations. The best three combinations of impellers were applied to the fermentation of welan. By analyzing the fermentation performance, the MB-4-6 combination had better effect on dissolved oxygen and velocity. The content of welan was increased by 13%. Furthermore, the viscosity of production were also increased.