Advantages of protection:
Provide protection from surge during the worst possible operating scenarios.
Provide flow that is greater than steady-state operation on the surge control line.
Prevent operation of the compressor in the stonewall (choke) region.
Avoid process air instability issues.
Linear characteristics are preferred for anti-surge valve trim.
Larger anti-surge valves may provide a better response to equalize pressure faster but can have poor controllability for throttling purposes during process control operation. If the recycle valve must operate in throttling mode, then it may be necessary
To install a small parallel valve to improve the control at low recycle-throttling rates. In parallel valve applications, the anti-surge controller can be set up for split-range output.