LGM Engineering received Approval in Principle from ABS for its multi-body, stacked “LGM–MMC” tank in July (credit LGM Engineering)
A new Type C tank suitable for LNG bunker fuel has been developed for dual-fuel vessels, especially small to medium container ships with high space utilisation.
LGM Engineering received Approval in Principle from ABS for its multi-body, stacked “LGM–MMC” tank in July. The tank is suitable for installation in higher, longer and narrower hold spaces and could also be used on ore carriers and other vessel types. The number of tank bodies incorporated into the design can be varied to meet specific space requirements.
The new tank has been under development since 2018 by China-based Gloryholder Liquefied Gas Machinery (LGM), which specialised in the design and turn-key delivery of marine LNG fuel gas supply systems and cargo handling systems for gas carriers and LNG bunkering vessels.
Type C tanks are designed using pressure vessel code criteria and conservative stress limits, so they do not require a secondary barrier. The new LGM-MMC tank will be made from the same materials as conventional Type C tanks and won’t require special consideration to achieve the same level of safety in that regard, says Technical Director Yun Chen. LGM carried out FEM calculations and temperature field analysis for various tank forms with different tank capacities and different stack numbers. The patented result achieves a space utilisation of over 79 percent, says Chen, which is more than conventional Type C tanks. The new tank meets stability requirements at all levels of liquid loaded and facilitates boil-off gas management. As only one set of equipment and instruments is required, the new design also saves money, he says.
Bin-Hong Wang, ABS Director of Engineering, Global Engineering (Shanghai), says that a key safety issue evaluated during the AIP related to the supporting structures for the tank which were given special consideration due to the high vertical centre of gravity and heavy weight of the tank. A sloshing analysis was conducted as well as a fatigue analysis for the connection between the horizontal plates and the tank shell, including tank support ends. He notes that as the AIP is a preliminary review, and the load will be different depending on ship size and installation location, strength calculations including yielding, buckling and fatigue analysis will be done again based on the details of specific projects.
ABS has been active in the development of technologies supporting LNG as bunker fuel and published its latest projections on carbon-reduction strategies for shipping in April, stating that the trade and regulatory landscape of short-sea vessels make them ideal candidates for early adoption of new technologies that promote environmental sustainability including new fuels such as LNG. As a low-carbon fuel, LNG can be combined with new technologies and operational measures to meet 2030 emissions-reduction goals, says ABS, and it can contribute to further reductions in future, if blended with bio-LNG. ABS has identified that the rate of shipping’s transition to lower carbon fuels will have the single biggest impact on its global carbon footprint; more than any predictable shifts in commodity demand, enhancements to operating practices, vessel routings or ship designs.