Design temperature and pressure of fermentation air buffer tank
Technical description on the design temperature and pressure of fermentation air buffer tank
As the core equipment of the biological fermentation process, the fermentation air buffer tank must be designed to comprehensively consider process requirements, material properties and safety specifications. The following specifications are given for its design basis and technical points:
1. Principles for determining design temperature
- Process temperature matching：
- The temperature of conventional aerobic fermentation processes is usually controlled at 25 – 37 ° C, and the design temperature of the buffer tank needs to be 5 – 10 ° C higher than the maximum process temperature to cope with instantaneous temperature rise and high temperature environment in summer.
- Special processes (such as high-temperature fermentation) need to be evaluated separately, and the design temperature can be increased to 60 – 80 ℃.
- Temperature resistance of material：
- The upper design temperature limit of carbon steel buffer tanks is 350 ° C, and the stainless steel material can reach 450 ° C, which needs to be selected according to the characteristics of the medium.
- The design of the tank insulation layer needs to consider the impact of ambient temperature, and an electric heat tracing system needs to be equipped in extremely cold areas (below-20℃).
2. Design pressure setting specifications
- System pressure matching：
- The design pressure needs to be 10%-20% higher than the maximum discharge pressure of the air compressor to cope with pressure fluctuations and safety valve tripping requirements.
- Typical configuration: When the air compressor exhaust pressure is 0.8MPa, the buffer tank design pressure is 1.0-1.1MPa.
- Safety factor requirements：
- According to the “Pressure Vessel Safety Technical Supervision Regulations”, the design pressure of the buffer tank shall not be less than 1.1 times the maximum working pressure.
- For flammable and explosive media, the design pressure needs to be increased by an additional 0.1-0.2MPa as a safety margin.
3. Typical working conditions parameter reference
| fermentation type | Typical process temperature (℃) | Design temperature range (℃) | Air compressor discharge pressure (MPa) | Buffer tank design pressure (MPa) |
|---|---|---|---|---|
| antibiotic fermentation | 28-32 | 40-45 | 0.6-0.8 | 0.8-1.0 |
| amino acid fermentation | 30-35 | 45-50 | 0.7-0.9 | 0.9-1.1 |
| organic acid fermentation | 35-40 | 50-55 | 0.8-1.0 | 1.0-1.2 |
4. Treatment measures for special working conditions
- High temperature fermentation scene：
- Equipped with a jacketed cooling system, circulating cooling water is used to control the tank temperature.
- Select high-temperature resistant sealing materials to ensure no leakage under 300℃.
- High-pressure fermentation scene：
- The wall thickness of the tank body is calculated at 1.2 times the design pressure, and stress analysis and verification are carried out.
- Equipped with a parallel system of dual safety valves to ensure reliable relief in case of overpressure.
V. Key points of operation and maintenance
- Daily inspection content：
- Check the displayed values of thermometers and pressure gauges every shift and record the deviations from the DCS system.
- Check the integrity of the safety valve lead seal every day and manually test the flexibility of opening and closing.
- Regular inspection items：
- The wall thickness of the tank body is tested every six months, focusing on monitoring stress concentration areas such as joints and manholes.
- Hydrostatic tests are conducted every year, the test pressure is 1.25 times the design pressure, and there is no leakage after holding the pressure for 30 minutes.
It is recommended that enterprises establish a special management system for pressure vessels and implement full life cycle management for special equipment such as buffer tanks. For continuous operation systems, an intelligent monitoring platform can be configured to collect temperature, pressure, liquid level and other parameters in real time, predict equipment status through data analysis, and achieve preventive maintenance. At the same time, it is recommended to conduct pipeline leak testing every quarter and entrust a third-party testing agency to issue a full quality report every year to ensure the continuous and safe operation of the system.