Mechanically stirred fermenter fermentation technology plays a particularly important role in the development of pharmaceutical and biological products. Among the many types of fermentation equipment, standard fermenters with both aeration and mechanical agitation are most commonly used, and are widely used in various fields such as antibiotics, amino acids, and citric acid. The key to the design of the standard fermenter is the complex gas-liquid two-phase flow problem. Mechanically stirred fermenters not only save considerable investment for pharmaceutical companies, but also save energy and other operating costs while increasing product yield and yield. In many processes, gas-liquid contact is important, and the gas needs to be in sufficient and effective contact with the liquid to provide sufficient mass transfer or heat transfer capability. For example, some chlorination and sulfonation reactions are fast reactions, which require a stirrer to provide high mass transfer strength; some reactions require absorption of oxygen that is difficult to dissolve, which in turn requires a stirrer to provide high dispersibility. Early studies have suggested that gas-liquid dispersion is formed by the gas being directly sheared into fine bubbles by a stirrer. However, recent studies have shown that gas-liquid dispersion is controlled by cavitation. When the gas velocity is too high or the stirring speed is too low, the whole agitator is wrapped by the air pocket, and the gas rises directly to the liquid surface through the agitator, and gas flooding occurs. The main processes of gas-liquid contact are as follows: residence time distribution required for gas phase and liquid phase, allowable pressure drop, relative mass flow rate, countercurrent contact, local mixing ability, need to replenish or remove heat, corrosion conditions, foam The behavior is separated from the phase, the flow pattern required for the reaction, the relationship between the reaction and the mass transfer, and the rheological behavior of the laminar flow and the transition zone. Most of these factors are closely related to the agitator. The gas dispersion in the stirred tank of the mechanically stirred fermenter has the following states: gas flooding state (most of the gas is not dispersed, the bubble rises directly to the liquid surface along the stirring axis), and the carrier gas state (the gas is basically dispersed, below the distributor) Poor distribution), completely dispersed state.