An FSRU (floating storage and regasification unit) is a moored vessel that receives LNG from a carrier, stores it in insulated tanks, warms it back into gas, and sends it out to a pipeline or grid. It is an import terminal on a hull, and the mirror image of an FLNG: one liquefies gas for export, the other vaporizes it for delivery. The attraction is speed and reversibility. A country can charter an FSRU and be importing gas in a fraction of the time an onshore terminal takes to build, then send the vessel away when it is no longer needed. The safety problem it inherits is cryogenic. LNG at roughly -162 °C makes ordinary carbon steel brittle on contact, so spill containment, low-temperature detection, and fast isolation of the transfer line carry more weight here than pressure relief does.
Functional safety relevance: Yes, though narrower than an FLNG. The vaporizer trains and the ship-to-ship transfer both carry instrumented protection, but there is no liquefaction train to protect.
Key Points
- Receives, stores, and regasifies LNG on board, then sends gas ashore by riser or pipeline. There is no liquefaction.
- Vaporizers may run on seawater, on a gas-fired closed glycol-water loop, or both, and the vaporizer trains carry most of the instrumented protection.
- Ship-to-ship transfer from a visiting LNG carrier is the highest-risk routine operation, governed by a linked emergency shutdown between the two vessels.
Example
Several European countries commissioned FSRUs through 2022 and 2023 to replace pipeline gas quickly. A chartered vessel moors at a jetty, an LNG carrier comes alongside and transfers cargo, and the FSRU vaporizes and meters gas into the national grid continuously, doing the job of an onshore import terminal that would have taken years to permit and build.
See Also: FLNG, onshore LNG regasification terminal, BLEVE
Cited Sources
- NFPA 59A, Standard for the Production, Storage, and Handling of Liquefied Natural Gas
- IMO International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code)