Anywhere compressed air can be eliminated represents an opportunity to reduce system operating expenses. Often, this reduction means fewer compressors must operate to meet the plant's air requirements.
Christopher Schmidt, Mark D'Antonio and Alan MacDougall
Install a flow meter in the recycle, cascade the flow set point with a pressure control loop. With proper tuning, the valve characteristics are lost in the flow control loop, which should be tuned fast with PI.
Electric variable-speed drives on lubricant-cooled and lubricant-free rotary air compressors are not a cure-all for system woes -- chemical plants must implement them correctly and at the right time to achieve maximum energy savings