Solution of air compressor pressure fluctuation exceeding 2bar due to large change in gas demand

Aiming at the problem that the pressure fluctuation of air compressor exceeds 2bar due to the large change of gas demand, the following systematic solutions are provided in combination with industry practice and technical analysis:

analysis of 1. core issues

1. demand Fluctuation and Pressure Coupling
   when the gas consumption increases instantaneously, if the air compressor does not respond in time, the system pressure drops; when the demand drops sharply, the pressure of the air compressor is not unloaded. The fluctuation of 2bar has exceeded the safety threshold of most devices (usually within ± 0.5bar).

2. Common Inducing Factors

   • equipment response lag: The loading and unloading of the traditional air compressor depends on the pressure switch, and the response delay leads to overshoot.
   • Insufficient capacity of gas tank: Small-capacity gas storage tanks cannot effectively buffer instantaneous demand changes.
   • Pipeline leakage: Air leakage accelerates pressure attenuation, forcing the air compressor to start and stop frequently.

2. Technology Solutions

scheme 1: Upgrade the frequency conversion control system

• principle: Adjust the motor speed in real time through the frequency converter to match the gas demand.
• Advantage:
  • the pressure fluctuation can be controlled within ± 0.2bar.
  • Energy saving 30%-50% (compared to power frequency machine).
• Key points of implementation:
  • vector control frequency converter is selected to ensure low frequency stability.
  • Configure the PID pressure closed-loop control algorithm.

Option 2: Optimize the configuration of gas storage tanks

• selection principle:
  • volume = single air compressor displacement x 6-10 minutes (empirical formula).
  • Example: if the displacement of the air compressor is 20m & sup3;/min, 1200-2000L is recommended for the air storage tank.
• Enhanced buffering:
  • multi-tank parallel reduces pressure pulsation.
  • Add orifice plate or vortex flowmeter to balance airflow.

Scheme 3: Intelligent joint control of multiple units

• strategy:
  • master-slave control: 1 inverter + N power frequency machines, the inverter is adjusted first, and the power frequency machine starts and stops step by step.
  • Dynamic load balancing: through the PLC distribution of running time, balance the wear and tear of each unit.
• Benefit:
  • extend equipment life by 30%-40%.
  • Reduce the impact of pressure shock on downstream equipment.

Scenario 4: Leak Detection and Repair (LDAR)

• detection means:
  • the ultrasonic detector locates the leak.
  • Soapy water to test joint/flange tightness.
• REPAIR STANDARDS:
  • pressure leakage rate ≤ 0.5%/h (refer to GB/T 3811-2008).

3.-assisted optimization measures

1. pressure switch calibration:
   • adjust the start-stop differential pressure to 1.5-2bar (the original setting may be too narrow).
2. Pipeline optimization:
   • reduce the elbow/variable diameter, reduce the resistance along the way.
3. Preventive Maintenance:
   • check valve/piston ring wear quarterly.
   • Validate safety valve/pressure gauge annually.

4. economic comparison

recommendations for 5. implementation

1. priority:
   • leak repair> frequency conversion transformation> gas tank expansion> joint control system.
2. Stage Advance:
   • short term: Carry out LDAR, calibrate pressure switch.
   • Medium term: add frequency converter or expansion tank.
   • Long-term: deploy intelligent joint control system.

By combining the above solutions, pressure fluctuations can be significantly suppressed, system stability can be improved, and energy consumption and maintenance costs can be reduced. It is recommended to select the most suitable transformation path according to the actual gas consumption curve and budget of the plant.