Working principle and application scope of stainless steel fermentation tank
Date:2022-01-06 Click:774
The air nozzle is used to spray high-speed air, and the air is dispersed in the liquid in a bubble form. On the ventilated side, the average density of the liquid drops by 1 drop. On the non-ventilated side, the density of the liquid is greater, and the liquid on the ventilated side is generated. The density difference is produced, thereby forming a circulation of the liquid in the fermenter. There are many types of air-lift fermentation tanks, the more common ones are internal circulation tube type, external circulation tube type, tensile cylinder type and vertical partition type. The outer circulation type circulation pipe is designed on the outside of the tank, and the inner circulation pipe is two, and the inside of the tank is designed. In the air-lift fermentation tank, the height of the circulation pipe is generally not higher than that. 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 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 a mechanically stirred aerated fermentor.
Main advantage:
(1) The structure is simple, the basic principle is not complicated, and the energy consumption is lower than that of a paddle reactor with stirring blades.
(2) Relying on gas to generate directional circulation instead of centrifugal pump mechanical equipment. The flow pattern is determined, the liquid circulation is strong, there are no moving parts inside, the shear stress is small, the energy dissipation is very uniform, and the material is sensitive to shearing force. Has a particularly important meaning;
(3) Compared with the traditional bubble tower, its operable gas and liquid flow rate range is much larger;
(4) The gas supply efficiency is high, and the gas flow in the riser pipe can be larger than the gas flow of the bubbling reactor, which is conducive to aerobic reactions;
(5) The fluidization effect is very good, it can be solid particles, even heavier particles are completely suspended.
Main disadvantage:
(1) Very large air throughput is required;
(2) Poor contact between phases;
(3) When the circulating organisms and operating conditions change, the amount of substrates, nutrients and oxygen cannot be kept consistent;
(4) Mixing and ventilation are coupled problems, that is, it is difficult to improve the mixing condition without changing ventilation.
Scope of application: Is widely used for large-scale production of single-cell protein. But it is not suitable for high-viscosity or a large amount of solids.
Main feature:
◆ Compared with mechanically stirred fermentation tanks, it can save electricity by 70%-80% and reduce costs.
◆ The aseptic operation is highly reliable. The equipment has no dynamic sealing device, no leakage, and no dead space in the equipment. The sterilization is thorough, and the chance of contamination with bacteria is greatly reduced.
◆ High heat and oxygen transfer efficiency, which can meet the fermentation production of various aerobic microorganisms in any region and season.
◆ Improve the yield and conversion rate. The mechanical shearing force of the equipment does little damage to microorganisms. In addition, sufficient dissolved oxygen and timely heat removal provide a good growth environment for microorganisms, which effectively promotes metabolism and accelerates product accumulation. The product yield and conversion rate are significantly improved.
◆ It is easy to realize large-scale and automatic, the equipment volume can be from 0.02m3 to 200m3, without manufacturing, installation, operation and maintenance difficulties. The control factor of the equipment is less than that of the mixing tank, and it is easy to realize automatic control.
◆ This equipment has the characteristics of low working noise, high charging coefficient, basically no maintenance, etc. The equipment investment is about 20% lower than that of the mixing tank. In addition, the original mechanical mixing tank can be modified without changing the external dimensions.
The equipment can be widely used in aerobic fermentation processes such as antibiotics, amino acids, enzyme preparations, vitamins, and organic acids. In chemical industry, it can be used in gas-liquid and gas-liquid-solid reaction processes. In terms of environmental protection, it can be used for sewage treatment. At present, the equipment is used for the production of glutamic acid, antibiotics, xanthan gum, glucoamylase, and citric acid in China. The volume of the equipment has reached 140m3, and it has achieved very significant economic benefits after being put into use. The air necessary for fermentation flows up and down inside and outside the static mixing element to drive the circulation of the fermentation liquid and promote the full mixing of gas and liquid.
