BoiloffGasManagement

BoiloffGasManagement refers to the set of practices and technologies used to control, recover, and utilize boil-off gas generated when cryogenic liquids absorb heat. Boil-off gas (BOG) forms as stored cryogenic liquids vaporize in insulated tanks or pipelines. Effective management aims to minimize gas losses, maintain safe pressure and temperature, protect equipment, and reduce environmental impact.

In liquefied natural gas (LNG) operations, BOG is a persistent consideration. Tanks and vessels continuously produce gas that must be vented, reliquefied, or burned in a controlled manner. Common approaches include controlled venting, reliquefaction to return gas to the liquid phase, combustion for energy recovery, and direct use of recovered gas as fuel for onboard machinery. Some systems route BOG through compressors to a reliquefaction plant, with any remaining energy used to power equipment or offset utility loads.

Key technologies include reliquefaction units (using mixed refrigerant or Claude cycles), turboexpanders coupled to generators for energy recovery, BOG compressors, and flare or vent systems for safety. Insulation quality, proper vent routing, and pressure-control devices are essential to minimize heat leak and manage boil-off rates. Modern plants use monitoring and control systems to optimise when to reliquefy, vent, or burn BOG.

Industry contexts include LNG terminals and carriers, cryogenic storage facilities, and certain spaceflight or research applications where cryogens are stored. Regulatory and safety considerations cover flammable gas handling, environmental emissions, and compliance with standards from authorities such as maritime or energy regulators.