Moss Maritime has developed & patented key solutions for the maritime LNG industry, such as the Moss LNG carrier, the Moss boil-off reliquefaction system, and the Moss LNG regasification system. Moss Maritime has been a pioneer in developing technology and engineering solutions for conversion of LNG carriers into FSRUs FSUs and FLNGs.
Making history with Moss
Moss Maritime has a special position in the maritime LNG industry, having developed the technology for Moss LNG carriers.
The Moss spherical LNG tanks are unmatched in reliability and flexibility for transporting LNG at sea, and its robust structure allows any filling level, with no concerns for sloshing problems. The robust and simple configuration of the spherical tank structure is a guarantee for problem free operation, and the system has never experienced any leaks or defects, unlike the main competing system.
Engineered with a unique supporting structure, the spherical tank is an un-stiffened structure which is simple to fabricate and minimize welding. The tank is insulated on the outside, meaning boil-off rates are easily adjusted to project requirements. Current designs are built with BOG rates down to 0.07% / day.
Since the tank’s introduction in 1973, around 140 Moss LNG carriers have been constructed at shipyards in Asia, Europe and USA, with cargo volumes ranging from 19.000m3 - 182.000 m3. Designs have the flexibility to accommodate the client’s needs, with cargo volumes ranging up to 265,000 m3. The modern designs are Panama Canal compliant with cargo volume of 180.000m3 and state of the art propulsion systems.
Boil-off Gas Reliquefaction System
The patented Moss Reliquefaction System for LNG carriers handles the boil-off gas (BOG) from the ship’s LNG tanks and returns it in liquid form back to the tanks, enabling preservation of BOG during the ship's voyage. The system hence presents flexibility in operation, and also enables the choice of a wider range of propulsion systems.
The BOG re-liquefaction is performed by extracting the heat from the BOG with a closed nitrogen compression/ -expansion cycle. This straightforward and footprint-friendly technology minimizes the required equipment which is fitted in the ship's cargo compressor room. The nitrogen cooling is reliable and operation-friendly, well suited for heavy seas operations.
The Moss reliquefaction system was chosen for installation on all 31 Q-flex LNG carriers for the Qatar project, and has in addition been installed on several LNG carriers with DFDE and ME-GI propulsion.
FSRU and Regasification Systems
Moss Maritime has developed proprietary technology for LNG regasification systems for installation onboard FSRUs (Floating Storage and Regasification Units). Several designs for open loop and closed loop operation have been developed, in order to meet various project requirements.
The Moss LNG regasification system was chosen for the world’s first FSRU conversion: the Golar Spirit FSRU, and new systems are being engineered for new projects. Moss Maritime is a market leader in technology and engineering for conversion of LNG carriers into FSRUs. Up to now Moss Maritime has prepared designs and performed engineering for 7 projects where LNG carriers have been converted to FSRUs, and in addition one project has been completed for conversion of an LNG carrier to an LNG FSU (Floating Storage Unit). Thanks to the multi-discipline engineering environment, Moss Maritime can take total engineering responsibility for such conversion projects.
Based on the successful pioneering of technology for conversion of LNG carriers into FSRUs, Moss Maritime started to develop concepts for conversion of LNG carriers into floating gas liquefaction plants (FLNG). This has resulted in patented concepts which were chosen by Golar LNG for the world’s first FLNG (the “Hilli Episeyo”) which was constructed on basis of converting a Moss LNG carrier. The project was realized through significant engineering effort by Moss Maritime, where knowledge of the existing ship system is essential for a successful project.
Moss Maritime has also developed concepts for small scale modularized liquefaction systems, based on the experience with the Moss BOG reliquefaction system, but enhanced in capacity and efficiency. The plant can be suitable for installation on FLNGs and small scale onshore plants.