The production of stainless steel vertical fermentation tanks should revolve around tank design, material selection, structural assembly, functional system integration, and performance testing. The following are detailed steps and key points:
1、 Tank design and material selection
Material requirements
Main material: 304 or 316L stainless steel is preferred. 304 stainless steel is corrosion-resistant and easy to clean, suitable for general fermentation scenarios; 316L stainless steel has a low carbon content, better welding performance, and stronger corrosion resistance, making it suitable for high demand or chloride ion environments (such as the pharmaceutical and food industries).
Inner wall treatment: The inner surface needs to be polished to ≤ 0.4 μ m to reduce material residue and microbial adhesion, ensuring hygiene standards.
External treatment: Choose mirror polishing (beautiful, easy to clean) or sanding treatment (rust proof, wear-resistant) according to the needs.
Tank shape and size
Shape: Adopting a cylindrical design, it facilitates uniform fluid flow and heat conduction.
Size: The capacity is determined according to the process requirements, and the working volume is usually 75% -80% of the full volume to ensure sufficient fermentation space.
Diameter to diameter ratio: Generally controlled between 1.7-4, a high diameter to diameter ratio is beneficial for dissolved oxygen, while a low diameter to diameter ratio facilitates mixing.
2、 Assembly of tank structure
Tank manufacturing
Tank processing: It is made by rolling or splicing stainless steel plates, and the plate thickness is determined according to the size and pressure requirements of the tank.
Can lid and bottom: The can lid and bottom are usually made of stainless steel plates and connected to the tank body by welding or bolts to ensure sealing.
Import and export pipelines: including feed ports (push valves or four valve groups), discharge ports, gas channels (surface and deep intake, exhaust, equipped with 0.2 μ m filters), etc., need to be arranged reasonably and ensure confidentiality.
Installation of mixing system
Blender type: Select paddle, turbine, or spiral agitator based on material viscosity and gas transmission requirements.
Mixing speed: Determine the optimal mixing rate based on the physical properties of the fermentation broth and gas transmission requirements to ensure good mixing and gas dissolution.
Blender position: Install at an appropriate height to avoid sedimentation at the bottom; Large tanks can use multi-stage agitators to improve mixing efficiency.
Power system: Select the appropriate motor according to the power requirements of the mixer, design a reasonable transmission system to ensure stable operation.
3、 Functional system integration
Temperature Control System
Jacket or coil design: A jacket or coil is installed on the outer layer of the tank to maintain stable temperature inside the tank through the circulation of cold and hot media.
PID controller: Equipped with a PID controller, it accurately controls heating or cooling equipment to maintain a constant temperature inside the tank.
Sterilization system
CIP/SIP system: Design online cleaning (CIP) and online sterilization (SIP) systems to ensure effective cleaning and sterilization of tanks between different batches.
Steam sterilization: The stainless steel tank can withstand steam sterilization at 121 ℃ for 30 minutes to kill miscellaneous bacteria.
Ventilation system
Gas distributor: Configure microporous distribution tubes (10-20 μ m pore size), sintered filter cartridges, or porous dispersion devices according to microbial needs to ensure uniform oxygen supply.
Ventilation control: For aerobic microorganisms, strengthen the ventilation system; For anaerobic microorganisms, weaken or shut down the ventilation system.
Monitoring and Control System
Sensor interface: Reserved monitoring interfaces for temperature, pH, dissolved oxygen, pressure, turbidity, etc., to monitor fermentation status in real-time.
Automated control: The automatic adjustment of parameters such as mixing rate, temperature, and ventilation rate is achieved through a PLC control system.
4、 Performance testing and maintenance
performance testing
Hydraulic test: Conduct a hydraulic test on the tank body to check its sealing and structural stability.
Airtightness test: Ensure that the tank is leak free through airtightness testing.
Run test: Simulate the actual fermentation process and test the collaborative effect of mixing, temperature control, ventilation and other systems.
maintenance
Regular inspection: Regularly check whether there are impurities or obvious leakage problems inside the tank, and inspect key components such as mixing equipment, heating/cooling equipment, sensors, etc.
Cleaning and disinfection: Clean and disinfect the tank body after each production, using common cleaning agents or disinfectants for cleaning.
Mixing equipment maintenance: Regularly inspect and maintain the mixing equipment to maintain the stability and effectiveness of the mixing motion.
Troubleshooting: Timely investigate and handle equipment malfunctions, such as stuck mixing equipment or malfunctioning sensors, to avoid losses and delays in production.