Cryostar develops new FGSS components

The shipping industry shows increased interest in reducing its global carbon footprint. There are at least two drivers to this trend: On the one hand, the legislator is calling for more stringent emission control regulations. MARPOL Tier III (for NO_x reduction) is already in force since January 2016 in coastal areas and further SO_x reduction will become mandatory on all seas in the imminent future. On the other hand, with the perspective of the recovery of the heavy fuel oil price from historically low values, opportunities may be unleashed with cleaner fuels being less expensive in comparison. Combine this with the new Ethane export market that has developed, in the context of the shale gas discovery in the US, and there is tremendous potential for innovative fuel supply systems.

Hartmann Reederei was one of the first ship-owners to embrace the use of ethane as a fuel, in order to comply with these stringent regulations. They selected AC Inox GmbH to facilitate the implementation of the fuel gas supply system (FGSS). Cryostar collaborated by suppling a number of key pieces of cryogenic equipment installed in its newly developed system.

The system is designed to feed either Ethane at 400 barg, or LNG at 300 barg as fuel to the MAN’s 7G50ME 12 MW main propulsion engine. The fully class approved FGSS, is installed on a semi-open deck and is expected to function for the entire 40-year vessel lifetime.

Cryostar’s long standing experience of delivering cryogenic equipment on-board LNG carriers ensured that few difficulties were encountered in adapting the already-referenced design to fulfil the specification and the related class requirements.

Cryostar designed, built and tested the following components to integrate the FGSS:

• Two submerged motor pump (Subtran) installed in two separate tanks.
• Two cryogenic reciprocating pump (MRP) built on a dedicated skid.
• One vaporiser skid with HP CWX heater and integrated glycol water heating loop.

After a number of project progress and interface meetings with DNV-GL’s active participation, the class issued the full design approval. The pumps, assembled at Cryostar’s headquarters in France, were successfully tested at full speed in the presence of the customer and owner.

During the Gas Trial and after delivery of the vessels, on site operational feedback highlighted some peculiarities specific to the use of Ethane. Aside from the higher pressures, some other challenges highlighted during operation were smoothly handled due to specific know how.

These gas carriers are currently operating between the US and Europe, mainly using ethane as fuel. The FGSS availability reaches an unparalleled rate of more than 95%, making this system the most efficient and reliable high-pressure 2-stroke marine ethane-fuelled propulsion system in operation.

Read the article online at: https://www.lngindustry.com/liquid-natural-gas/30092019/cryostar-develops-new-fgss-components/