Application of Compressed Air in Fermentation Production

A note on the application of compressed air in fermentation production

as the core power source of fermentation process, compressed air runs through the whole process of strain cultivation, fermentation metabolism and product separation, and its quality stability and supply reliability are directly related to fermentation efficiency and product quality. After technical analysis and industry practice verification, the application scenarios and technical requirements are described as follows:

1. core process support functions

1. aeration agitation system
   • provide sterile air for the fermentation tank, and realize the ventilation ratio of 0.2-1.5vvm through the microporous aerator to meet the metabolic requirements of different strains (such as aerobic bacteria need to be ≥ 0.5vvm).
   • The mechanical stirring device is driven to maintain the dissolved oxygen coefficient (KLa value) of the fermentation liquid in the range of 50-200h and sup1; to ensure the oxygen supply balance between the growth of the bacteria and the synthesis of the product.
2. Environmental Control Guarantee
   • maintain the positive pressure environment of the fermentation workshop (pressure difference 5-10Pa) to prevent the intrusion of external polluted air.
   • Drive the air conditioning system to achieve precise control of temperature ± 0.5 ℃ and humidity ± 3% RH to meet the growth requirements of specific bacteria (such as mold needs 25-28 ℃ and relative humidity 70-80%).
3. Material conveying power
   • through the pneumatic diaphragm pump to achieve culture medium raw materials, defoaming agent and other materials without pollution transport.
   • Drive the powder delivery system, the carbon source, nitrogen source and other raw materials according to the formula ratio of precise dosing (dosing error ≤ ± 1%).

Special requirements for 2. air quality

1. cleanliness standard
   • oil content: ≤ 0.01 mg/m & sup3;(Adopt coalescing filter + activated carbon adsorption double treatment)
   • dust content: 0.1μm particle size particle concentration ≤ 1000 particles/m & sup3;(equipped with HEPA filter)
   • microbial limit: the total number of bacterial colonies ≤ 10CFU/m & sup3;(by ultraviolet sterilization + membrane filtration technology)
2. special process adaptation
   • antibiotic fermentation: a sterilizing filter (filtration efficiency ≥ 99.9999) is required to ensure air sterility.
   • Enzyme preparation production: it is necessary to control the dew point temperature of compressed air ≤-40 ℃ to avoid condensation water affecting enzyme activity.

Technical Specification for 3. System Configuration

1. equipment selection principle
   • main air compressor: the exhaust volume is configured according to 120 of the maximum air consumption condition, and equipped with frequency conversion speed regulating device to realize 30-100% load regulation.
   • Standby unit: configured according to 50% of the capacity of the main equipment to ensure continuous operation of the system in case of single machine failure.
   • Purification device: equipped with freeze dryer (-20 ℃ pressure dew point) and precision filter (0.01μm filtration accuracy).
2. Key Points of Pipe Network Design
   • the main gas supply pipe network adopts annular arrangement, the pipe diameter is designed according to the economic flow rate of 8-15 m/s, and the pressure loss is less than or equal to 0.1MPa.
   • Independent branch pipes are set at key gas points, equipped with pressure regulating valves and flow meters to achieve precise control.
   • Drainage system: 1 automatic drain valve shall be set for every 50 m pipeline, and the oil content of condensed water shall be ≤ 5mg/L.

4. operation and maintenance management standard

1. routine Inspection Procedures
   • check the compressor discharge temperature (normal value 75-95 ℃), oil level (1/2-2/3 of the observation window) and vibration value (≤ 5 mm/s).
   • Check the dew point indication of the dryer (relative humidity ≤ 35% at -20 ℃) and the differential pressure of the filter (alarm value 0.05MPa).
   • Check the safety valve of the air tank (the setting pressure is 1.05-1.1 times of the design pressure).
2. Regular Maintenance Items
   • replace lubricating oil, oil filter and air filter every 2000 hours (three filter replacement cycle).
   • Purge the pipe network every quarter to remove rust residue and condensate in the pipe.
   • Entrust professional institutions to carry out pressure vessel testing every year, and implement TSG 21 Safety Technical Supervision Regulations for Stationary Pressure Vessels.

5. intelligent monitoring and energy efficiency optimization

1. online monitoring platform
   • real-time acquisition of 12 operating parameters (pressure, temperature, flow, power, etc.), data update period ≤ 1 second.
   • Set the three-level alarm threshold (warning value/alarm value/shutdown value) to realize early fault warning.
   • Generate daily/monthly/annual operation reports, including energy consumption analysis, equipment utilization and other key indicators.
2. Energy Efficiency Management Strategy
   • the compressor start-stop strategy is optimized by the load curve to achieve more than 30% energy saving effect.
   • Monitor the specific power (kW/m & sup3;/min) and continuously optimize the system energy efficiency (primary energy efficiency ≤ 5.5kW/m & sup3;/min).

As the "invisible artery" of fermentation production, the stable operation of compressed air system is directly related to the production efficiency and product quality. Enterprises should establish a full life cycle management system, combined with SCADA monitoring system and preventive maintenance strategy, to ensure that the system continues to provide high-quality, reliable compressed air power, for the stable operation of the fermentation process and the continuous improvement of product quality to provide a solid guarantee.