I want to share you how to size or select minimum capacity of air compressor and instrument air dryer. Air compressor is usually used as feed air for:
- Instrument air (for instrumentation or feed air for nitrogen generator)
- Utility air (for utility station)
Instrument Air Requirement for Instrumentation
Instrument air is required in operation of control valve and shut down valve. The rules below is used to calculated instrument air requirement for instrumentation:
- Control valve (CV) – steady state condition: 1 scfm/valve
- Control valve (CV) – transient condition: 6.25 scfm/valve
- Shut down valve (SDV) – steady state condition: 0
- Shut down valve (SDV) – transient condition: 4.8 scfm/valve