Compressor Anti-Surge Control
Understand why surge is damaging, how an anti-surge controller protects the compressor and why recycle-valve response, instrumentation quality and operating margin matter.
System context
Compression systems
Technical topic pages show the knowledge scope behind LNG University learning. Course, assessment and credential availability depends on the applicable program.
Relevant roles
Control-room personnel · Process-control engineers · Instrument technicians · Rotating-equipment engineers
Prerequisites
Centrifugal compressors · Process control fundamentals
Knowledge level
Advanced technical coverage with system and operational context.
Learning outcomes
What this topic is intended to help you understand
- Describe compressor surge in operational terms.
- Explain the purpose of the surge-control line and recycle path.
- Identify common measurements and final control elements used by anti-surge systems.
Technical scope
Equipment, concepts and terminology
- Compressor map
- Surge line and control line
- Reduced flow concepts
- Pressure and temperature compensation
- Recycle valve dynamics
- Fast-opening logic
- Controller margin
- Interaction with process control
Operating context
How the topic connects to plant operation
- Recognizing approach to surge
- Effects of rapid process disturbances
- Startup and shutdown protection concepts
- Recycle-valve monitoring
Safeguards and controls
Protection and risk-control context
- Dedicated anti-surge function
- Instrument validation
- Fail-safe recycle behavior
- Trip logic where required
Technical learning does not replace site procedures, OEM documentation, engineering calculations, permits, supervision or facility-specific authorization.
Engineering documents
Documents commonly connected to this subject
- Compressor map
- Control narrative
- Logic diagram
- P&ID
- Cause & effect chart