Abstract:

At present, tubular gas distributor is widely used in airlift loop bioreactor, which is easy to block and has low power efficiency. There are few reports on the application of microporous gas distributor with small bubble size and high dynamic efficiency in airlift loop bioreactor. In order to study the actual effect of microporous gas distributor applied in airlift loop bioreactor, the structure optimization of microporous gas distributor was studied, and the influence of the type, diameter and installation position of the distributor on the oxygen mass transfer coefficient was investigated, and then the performance parameters such as the oxygen filling capacity, oxygen utilization rate and dynamic efficiency of the optimized microporous gas distributor and their change laws were investigated. The optimal design parameters were obtained of microporous gas distributor to provide guidance for their industrial application. The results showed that disc-type microporous distributor had a better mass transfer performance than the tube-type one. When the disc-type distributor diameter was 0.4R and the distance from the distributor to the draft-tube bottom was 1R, in which R is draft-tubeinner radius, the oxygen transfer coefficient was biggest. The study also indicated that the suitable gas rate was 1.5m³/h, and at this point, oxygenation capacity was 0.14 kg/h with oxygen utilization rate 34.63% and dynamic efficiency 3.35kg/(kW·h).

Key words: loop bio reactor, microporous gas distributor, oxygen transfer coefficient, performance parameters

摘要：

目前，气升式环流生物反应器普遍使用管式气体分布器，管式气体分布器易堵塞，动力效率低。气泡粒径小，动力效率高的微孔气体分布器应用于气升式环流生物反应器的研究少有报道。本文为研究微孔气体分布器应用于气升式环流生物反应器的实际效果，对微孔气体分布器进行结构优化研究，考察分布器形式、直径和安装位置等因素对氧传质系数的影响，进而考察优化后的微孔气体分布器的充氧能力、氧利用率、动力效率等性能参数及其变化规律。指导微孔气体分布器的工业化应用。实验结果表明：盘式微孔气体分布器传质效果优于管式，且盘式微孔气体分布器直径为0.4R时，传质效果最佳；膜盘到导流筒底部距离为1R时，分布器的氧传质系数最大，R为导流筒半径；微孔气体分布器适宜的气体流量为1.5m³/h，充氧能力0.14kg/h，氧利用率为34.63%，动力效率为3.35kg/(kW·h)。

关键词: 环流生物反应器, 微孔气体分布器, 氧传质系数, 性能参数