Fermentation tanks have been widely used in the pharmaceutical, enzyme, monosodium glutamate, and food industries as a device for microbial fermentation. It improves fermentation efficiency by optimizing the fermentation conditions of microorganisms. According to the aerobic and anaerobic properties of the cultured microorganisms, fermenters can be divided into aerobic and anaerobic types. Fermentation tanks generally have good liquid mixing ability, heat transfer rate, and reliable detection and control instruments.
Fermentation tank is a kind of biological reaction equipment with simple structure, not easy to contaminate bacteria, high efficiency of dissolved oxygen, low energy consumption, etc. It is widely used in biological reactions. There are many types of air-lift fermenters that have been widely used in the biological industry, including air-lift inner circulation fermenters, gas-liquid double jet air-lift circulation fermenters, and tower-type air-lift fermenters with multi-layer distribution plates. The bubbling tank is the most 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.
The fermenter uses the air nozzle to spray high-speed air, and the air is dispersed in the liquid in the form of bubbles. On the ventilated side, the average density of the liquid decreases by 1, and on the non-ventilated side, the liquid density is higher, resulting in a difference with the ventilated side. The resulting liquid creates a density difference that creates a circulation of the liquid in the fermenter. There are many forms of airlift fermentation tanks, the more common ones are inner circulation tube type, outer circulation tube type, tension drum type and vertical baffle type.
The outer circulation type circulation pipe is designed outside the tank body, and there are two inner circulation pipes, which are designed inside the tank body. In the airlift fermentation tank, the liquid level in the tank is not higher than the outlet of the circulation pipe, and not lower than the outlet of the circulation. The advantages of the air-lift fermentation tank are low energy consumption, small frying and cutting effect in the liquid, and simple structure. Under the same energy consumption, its oxygen transfer capacity is much higher than that of mechanically stirred and aerated fermenters.
The main components of fermentation tank equipment include kettle body, heat transfer device, stirring device, and shaft sealing device. Other accessories are also added as needed, such as welding manholes, hand holes and various interfaces for easy maintenance of internal parts, feeding and discharging, installation of thermometers, sight glasses, pressure gauges, and effective monitoring and control during operation. Material temperature, pressure safety relief device, etc. The kettle body is generally composed of simplified and two heads, and its function is to provide a certain space for the chemical reaction of the material. The stirring device is composed of a transmission device, a stirring shaft and a stirrer. Its function is to uniformly mix various materials participating in the reaction, so that the materials are in good contact and accelerate the progress of the chemical reaction.
The heat transfer device of the fermentation tank is to set a coil inside the kettle body or set a jacket outside the kettle body to control the temperature of the material within the required range of the reaction. The shaft sealing device is the seal between the stirring tank and the stirring shaft to prevent the escape of reaction materials and the infiltration of sundries. Usually packing seals or mechanical seals are used.
