A biological fermentation tank is a type of biological reaction equipment that has the advantages of simple structure, low bacterial contamination, high dissolved oxygen efficiency, and low energy consumption, and is widely used in biological reactions. There are various types of gas lift fermentation tanks that have been widely used in the biotechnology industry, including gas lift inner loop fermentation tanks, gas-liquid dual jet gas lift loop fermentation tanks, and tower type gas lift fermentation tanks with multi-layer distribution plates.
The working principle of a biological fermentation tank is to use an air nozzle to spray high-speed air, which is dispersed in a bubble like manner in the liquid. On the ventilated side, the average density of the liquid decreases by 1, while on the non ventilated side, the liquid density is higher, resulting in a density difference with the liquid on the ventilated side, thus forming a circulation of the liquid inside the fermentation tank. There are various forms of air lift fermentation tanks, with the most common being the internal circulation tube type, external circulation tube type, tension tube type, and vertical partition type.
The external circulation pipe is designed outside the tank, while the internal circulation pipe consists of two pipes designed inside the tank. In an air lift fermentation tank, the height of the circulation pipe is generally not higher than. 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 pipe. The advantages of an air lift fermentation tank are low energy consumption, minimal frying and cutting in the liquid, and simple structure. At the same energy consumption, its oxygen transfer capacity is much higher than that of a ventilated fermentation tank with mechanical stirring.