Boil-Off Gas (BOG) Compressors
Study the role of BOG compressors in controlling LNG tank and transfer-system vapor generation while maintaining a stable vapor-handling path.
System context
BOG management
Technical topic pages show the knowledge scope behind LNG University learning. Course, assessment and credential availability depends on the applicable program.
Relevant roles
LNG terminal operators · Control-room personnel · Mechanical technicians · Process engineers
Prerequisites
LNG properties and cryogenics · Centrifugal compressor fundamentals
Knowledge level
Intermediate technical coverage with system and operational context.
Learning outcomes
What this topic is intended to help you understand
- Explain why BOG is generated and how compression supports tank pressure control.
- Trace typical suction, compression, recycle and downstream BOG destinations.
- Recognize interactions among tank pressure, compressor capacity and recondenser or fuel-gas demand.
Technical scope
Equipment, concepts and terminology
- BOG sources
- Suction drums
- Compressor stages
- Intercooling where applicable
- Recycle
- Seal systems
- Capacity control
- Downstream destinations
Operating context
How the topic connects to plant operation
- Tank-pressure response
- Managing changing sendout or unloading conditions
- Compressor sequencing concepts
- Monitoring suction superheat and discharge conditions
Safeguards and controls
Protection and risk-control context
- Anti-surge control
- Low suction pressure protection
- High discharge temperature
- Vibration and seal alarms
- ESD integration
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
- BOG PFD
- BOG compressor P&ID
- Compressor map
- Cause & effect chart