Compressed air quality for fermentation
The quality standard of compressed air for fermentation involves several key indicators to ensure the smooth progress of the fermentation process and the output of high quality products. The following is a detailed analysis of the quality of compressed air for fermentation:
1. pressure
the pressure of the compressed air for fermentation needs to be stable and suitable to ensure that the compressed air can be smoothly delivered to the fermenter. In general, the air pressure at the outlet of the air compressor is controlled between 0.2-0.35MPa (gauge pressure) or 0.2-0.4MPa. This range can meet the needs of the biological industrial production process, while avoiding the compressor outlet air pressure is too high, thereby saving power consumption and reducing production costs.
2. flow
the flow rate of compressed air is calculated based on the total fermenter volume of the fermentation plant or fermentation plant. Usually, the required compressed air flow rate is determined by the aeration ratio of the pilot test or VVM (the volume of air per unit volume of medium per unit time under standard conditions) to ensure continuity and stability in the production process.
3. temperature
the temperature of the air entering the fermenter needs to be 10-30°C higher than the fermentation temperature. This requirement helps to maintain the stability and efficiency of the fermentation process. However, with the development of technology, many factories have canceled the heating treatment of the air before entering the tank, but directly after the air is dehumidified by the cold dryer.
4. humidity
A suitable humidity helps to maintain optimal conditions for the biological reaction. The relative humidity of the compressed air entering the total filter should be controlled between 60% and 70%. This is because the total air filter filter medium of the fermentation plant usually uses polytetrafluoroethylene, which will greatly reduce the filtering effect after the filter medium is affected with moisture.
5. cleanliness
the cleanliness of compressed air for fermentation is extremely high. It must be sterile, dust-free, impurity-free, water-free, oil-free and maintain positive pressure. Specific standards may vary depending on the fermentation process and product requirements, but the following levels are generally required:
- suspended particles: The concentration shall meet the standard of Class D clean area or higher, I .e. the number of particles ≥ 0.5μm per cubic meter of air shall not exceed a certain limit (the specific value may vary according to different standards, and some data suggest that it should be ≤ 3520000/m). In some cases of high requirements, it is even necessary to meet the-level clean area standard.
- Microorganisms: The bacteria content should be reduced to zero or reach the level of cleanliness 100, that is, the maximum allowable number of microorganisms per cubic meter of air is 5 floating bacteria/m³ and 1 settling bacteria/m³.
- Moisture: Should comply with relevant standards, such as GB/T13277-1 Level 2 standard, dew point ≤-40 ℃ (corresponding absolute humidity value is 0.176 g/m).
- Oil: The content should be extremely low, generally ≤ 0.1 mg/m.
6. Aseptic Processing
due to the high demand for sterile air in the fermentation process, the compressed air must be treated aseptically. This is usually achieved through high-efficiency air filtration systems, such as the use of filter media such as polytetrafluoroethylene, and periodic sterilization. In addition, advanced sterilization technology, such as VHP pipeline sterilization technology, can be used to ensure the safety and reliability of the aseptic ventilation system.
7. Other Considerations
- regular inspection: Compressed air should be tested regularly to ensure that its quality meets standards. Test items may include pressure, flow, temperature, humidity, cleanliness and sterility.
- Equipment selection: When choosing air compressors and related equipment, the needs and characteristics of the fermentation process should be fully considered to ensure the performance and reliability of the equipment.
In summary, the quality standard of compressed air for fermentation involves a number of key indicators, which together ensure the smooth progress of the fermentation process and the output of high quality products. In actual production, relevant standards and specifications should be strictly observed to ensure the quality of compressed air for fermentation.
