FLNG

Floating liquefied natural gas (FLNG) refers to a floating facility that produces LNG by processing natural gas at sea, liquefying it on site, and storing the LNG for export. FLNG units are typically self-contained ships or barge-like structures that combine a topside processing plant with insulated LNG storage tanks and cargo handling equipment.

Process and operations: natural gas is produced from offshore wells and delivered to the FLNG unit, where it undergoes pretreatment to remove water, acids, and impurities. The gas is then cooled through a liquefaction process to LNG temperatures and stored in cryogenic tanks. LNG is transferred to carriers for shipment to markets. Floating regasification units (FSRU) exist separately to convert LNG back to gas, while most FLNG facilities focus on producing and exporting LNG rather than regasifying it.

Designs and configurations: FLNG facilities can be ship-shaped or barge-like and are typically moored to a field using turret, spread mooring, or dynamic positioning systems. They integrate a gas pretreatment unit, liquefaction cycles (often using refrigerant-based processes), LNG storage tanks, and a cargo transfer system for loading LNG onto carriers.

History and examples: the concept emerged in the 1970s, with the first commercial FLNG project being Shell’s Prelude off Australia, in operation during the late 2010s. Petronas has advanced FLNG with units such as PFLNG Satu and PFLNG2 for offshore gas fields, among others planned or deployed by various operators.

Advantages and challenges: FLNG can reduce development time and capital expenditure for remote or small offshore gas fields by avoiding extensive onshore infrastructure. However, FLNG projects require substantial upfront investment and sophisticated offshore engineering, and they face safety, environmental, and operational challenges in harsh marine environments.