Solve

In theory, anti-surge systems calculate a surge curve for the unit (the red line in the diagram), and based on this surge curve, they determine a certain lead time (which should be 10% in the diagram) to generate an alarm curve (the green line), thereby enabling the anti-surge valve to intervene and make adjustments in advance. Within the safe area (below the green line in the diagram), the anti-surge valve is normally regulated using PID to meet the process requirements such as the specified pressure values. When the operating point (the cross mark in the diagram), which is determined based on the outlet flow rate, upstream and downstream pressures, and temperatures of the unit, approaches the alarm curve (the green line in the diagram), the anti-surge control system takes precedence over PID by generating an AO valve signal to open the valve and increase the outlet flow rate of the unit. When the operating point reaches the surge curve (the red line in the diagram), the solenoid valve of the anti-surge valve activates immediately, causing the valve to open fully and rapidly in order to ensure the safe operation of the unit. The above is for reference only; the specific anti-surge control logic must be verified against the actual system!