(90b) Objectives of Anti-Surge Control

Preventing a compressor surge is the primary purpose of an anti-surge controller. However, there are additional requirements that must be met for an anti-surge control package to be effective. It must be stable and reliable, while also keeping energy costs to a minimum.

For an anti-surge control project to be judged successful, performance control must be smooth and stable while the recycle valve is open. The compressor must be able to start and shutdown without surging or excessively upsetting the process.

Control valves must be fast-acting, yet able to move in small increments. Transmitters must report the correct process conditions to the anti-surge controller over the full range of startup and running conditions. Flow meter sensing lines must be impervious to condensation resulting from temperature changes.

Depending on the application, recycle or venting must be kept to a minimum to reduce energy consumption.

This paper addresses some of the challenges that must be met when designing an anti-surge system.