Titan LNG Develops Novel Tank Concept for Future IWW Bunker Barges

As part of its current fleet of bunkering assets, Titan LNG operates the LNG bunker barges FlexFueler 001 and 002. The one-of-a-kind “FlexFueler” concept was developed in-house by Titan LNG and represents the first generation of LNG bunker assets tailor-made for the Antwerp-Rotterdam-Amsterdam area. Through concept development and operation of these barges, Titan LNG has gained a lot of experience with the European Inland Waterway (IWW) regulations, specifically their impact on LNG storage and handling systems.?

Continued market growth and the higher tank capacity of the global fleet of LNG-fueled vessels is leading to more and larger IWW-dedicated bunker barges. However, scaling up to meet the market requirements efficiently is made difficult by a particular rule in the European code for carriage of dangerous goods. Namely, a tank capacity limit of 1,000 m3 per tank onboard bunkering barges. Which – when conventionally interpreted – leads to a multiple of 1,000 m3 cylindrical tanks. Though certainly valid from a safety perspective, the rule is a challenge when scaling up liquefied gas carriers as it tends to lead to designs with many small – and relatively expensive – tanks.

Titan LNG has devised a way to meet this safety criterion by introducing the principle of multiple 1000 m3 internal tank partitions into a single tank structure. The main benefit is that more fuel can be put into a single tank structure. As a result, the tanks take up less space, thus reducing the total footprint of the vessel while maintaining the cargo capacity. The internal partitions maintain their individual structural integrity in case of tank damage to a single partition. This solution has been patented as well as technically validated for one of the more challenging types of pressure vessel; a bilobe tank.

Fleet development director Douwe de Jong commented: “As more LNG and LBM fueled vessels are built, innovations like this will become increasingly important to efficiently meet demand and effectively scale up supply infrastructure. By investing in the in-house development of its fleet, Titan LNG has managed to introduce the economies of scale associated with large LNG tanks found in seagoing vessels into IWW gas carrier vessel design. “

The design impact was investigated within Titan LNG’s “Hyperion” IWW bunker vessel design series. At a total capacity of 8,000 m3, the vessel’s length and breadth were reduced by 10-20%, compared to the individual tank approach. Fuel consumption, steel weight, outfitting costs and overall environmental impact of constructing and operating the vessel were reduced by similar percentages. The larger tank size also opened the possibility of using lighter and cheaper foam-insulated tanks instead of the vacuum-insulated pressure tanks that are more common in the <1,000cbm tank size range. It was also found that the resulting vessel lay-out and dimensions could work as both a seagoing and inland vessel. As a result, the “Hyperion” series currently features both seagoing and inland design versions, making it ready for the next decade and beyond.

Titan LNG cooperated with HB Hunte Engineering, who proved the structural feasibility of the tank concept. HB Hunte Engineering is also working with Titan LNG's on the 4,500cbm bunker vessel design "Krios". Tank images courtesy of HB Hunte.