好氧发酵体系的微界面传质强化反应器构效调控研究

Due to the shortcomings in traditional aerobic fermentation reactors, such as low oxygen utilization and high energy consumption, caused by high air usage and big bubbles, it is necessary to investigate the transfer characteristics of oxygen and the influence of bubble morphology and gas-liquid mixing performance on the fermentation process. The micro-interface mass transfer strengthening and structure-activity regulation of oxygenated fermentation will be achieved. Combining the super fine bubble breaking agitator (SBBA) with the super fine bubble breaking distributor (SBBD) makes a gas-liquid mass transfer and fermentation system at the micron level interface, and the paddle can be replaced by flexible agitation of gas liquid flow. The gas-liquid turbulence will be promoted to improve the mass transfer and reaction, to achieve a substantial increase in the oxygen utilization and a decrease in the amount of sterile compressed air. In the laboratory simulation test device, high-speed camera, Q-CT and CCD technology are used to obtain the bubble size, fluid flow and other mass transfer concerned information. Moreover, the mass transfer and fermentation reaction kinetics related data of the actual system is measured in 10m3 penicillin fermentation reactor. The relationships between the structure of the fermentation reactor morphology, fluid flow behavior and mass transfer enhancement can be constructed to establish the bubble scale regulation model for the aerobic fermentation systems. Taking the penicillin fermentation as an example, based on the mathematical relationship between the structure - interface and interface - energy of the fermentation reactor, the energy - efficiency regulation mechanism of Micro interface mass transfer reactor can be built, which lays a theoretical foundation for the development of a new generation of aerobic fermentation reactor and control method with high efficiency and low energy consumption.

由于传统好氧发酵反应器存在气泡大、空气用量大所引起的氧利用率低、能耗高等问题，考察氧的传递特性，明确气泡形态和气液流动对发酵过程的影响，实现好氧发酵的微界面传质强化十分重要。将超细气泡破碎搅拌器（SBBA）和超细气泡破碎分配器(SBBD)相结合，形成微米级界面的气液传质与发酵系统，并采用气液流柔性搅拌替代桨式刚性搅拌，促进体系的气液湍流，强化了发酵体系的传质与反应，进而提高氧利用率并减少无菌空气用量。在实验设备上，采用高速摄像、Ｑ-CT及CCD技术获取气泡尺寸、流体流场等气液传质相关信息，并在10m3青霉素发酵罐内测定发酵体系氧传质与发酵数据，明确发酵反应器结构—气泡形态—流体流动—传质强化关联，建立气泡尺度调控模型。以青霉素发酵为例，基于发酵反应器结构—界面、界面—能量的数学联系，建立微界面传质强化反应器构效调控机制，为开发新型高效、低能耗的新一代好氧发酵反应器奠定理论基础。

针对高效发酵过程的开发，建立微气泡形态控制模型，明确微气泡尺寸与流体物性、温度压力等操作条件与反应器结构等因素的关联关系。结合反应器下降管内的能量耗散速率的计算，构建反应器气含率、气液相界面积的计算模型，形成微界面反应器内气泡形态—气液流动行为—气含率—相界面积关联关系。建构建微气泡冷模实验及气泡测量系统，结合气泡识别与统计软件，利用高速显微摄像系统快速准备地表征微气泡体系。通过气泡运动和传质的耦合，明确气泡初始直径对气泡上升过程中传质的影响，确定有效传质高度，从而形成气泡尺寸与反应器结构尺寸的关联，获得反应器内整个液层内的气含率、气液相界面和传质速率。以微界面取代传统反应器的毫-厘米级宏界面，开发微界面传质强化新型生化反应器，提升发酵过程中气体利用率，降低生产能耗、提升发酵效果，从而取得较好的经济效益。