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A brief description of the advantages of the operation and use of the fermenter

    Fermenters are also widely used biological reaction equipment. This type of reactor has the advantages of simple structure, not easy to contaminate bacteria, high efficiency of dissolved oxygen, and low energy consumption. There are many types of airlift reactors, the common ones are airlift circulation type, bubbling type, air injection type, etc. Airlift fermenters that have been widely used in the biological industry include airlift inner circulation fermenters, gas-liquid double injection Airlift circulating fermenter, tower type airlift fermenter with multi-layer distribution plate.

    The fermentation tank is a relatively primitive aerated fermentation tank. Of course, there is no guide tube in the bubbling reactor, so the directional flow of the main body of the liquid is not controlled. Now take the airlift loop reactor as an example to illustrate its working principle. The characteristics of the airlift loop reactor have been briefly mentioned above. Since there is no agitator in the airlift loop reactor and there is a directional circulating flow, it has many advantages, which will be described in detail below.

    1. Uniform distribution of the reaction solution: Uniform mixing of gas-liquid-solid three-phase and good mixing and dispersion of solution components are common requirements for bioreactors, because the distribution of flow, mixing and residence time are all affected. For many aerated fermentations with intermittent or continuous feeding, the substrate and dissolved oxygen are dispersed as uniformly as possible to ensure that the concentration of the substrate everywhere in the fermenter falls within the range of 0.1% to 1%, and the dissolved oxygen is 10% to 30%. . This is beneficial for the growth and product production of aerobic biological cells. In addition, it is necessary to avoid the formation of a stable foam layer on the liquid surface of the fermenter, so as to avoid the accumulation of biological cells and damage or even death. There are also medium components, especially starchy granular materials that are easy to settle, and should be able to be suspended and dispersed. Airlift loop reactors can meet these requirements well.2. Higher dissolved oxygen rate and dissolved oxygen efficiency: The airlift reactor has a higher gas content and a specific gas-liquid contact interface, so it has a high mass transfer rate and dissolved oxygen efficiency. The volumetric oxygen efficiency is usually higher than that of mechanical The stirring tank is high, the kLd can reach 2000h, and the power consumption of dissolved oxygen is relatively low.

      3. Small shear force and little damage to biological cells: Since the airlift reactor has no mechanical stirring impeller, the shear damage to the cells can be minimized, especially suitable for the cultivation of plant cells and tissues.

      4. Good heat transfer: a lot of fermentation heat is generated in aerobic fermentation. For example, the fermentation heat in the vigorous period of yeast culture is as high as 3.0 ~ 4.0×105kJ/(mh), while the heat transfer temperature difference is only a few degrees (℃), especially in summer, if using Non-chilled water is only about 3-10 °C, so a large heat exchange area and heat transfer coefficient are required. The fermentation tank has a high liquid comprehensive circulation rate, and it is convenient to install a heat exchanger on the external circulation pipeline to ensure that the fermentation heat is removed to control the appropriate fermentation temperature.