Naval Architect Structure Engineering Group
Japan Marine United Corporation
17:00 - 17:30
Thursday, 19 September 2019
T1.10 Development of SPB® LNG Tank for Bunkering Ship
Demand of the liquefied natural gas (LNG) fueled vessels are increasing as a solution for satisfying IMO’s emission control requirements. Thus it is predicted that the LNG fuel bunkering vessels will be needed with increase of commercial ships which uses LNG as fuel. On the other hand, the social trend of LNG use as fuel has just started and stable demand of LNG fuel bunkering vessel has not yet established.
To respond to such situation, Japan Marine United (JMU) Corporation has designed the bunkering vessel which can handle LNG and also heavy crude oil. This report introduces the bunkering vessel handling dual fuel.
The cargo tank of bunkering vessel will be exposed to more severe variable load due to loading and unloading cargo than LNG carriers. Internal vapor pressure is also able to increase and decrease with regard to various matter, those are how large capacity the refueled commercial vessel’s GCU has, internal pressure of the fuel tank, how long time it takes for cooling down, and so on.
We have considered such load-unload circumstances as design condition for fatigue strength and crack propagation evaluation based on the abundant experience of design SPB® tank, which is a self-supporting prismatic-shape tank satisfying the requirement of IMO Type B tank.
With regard to principal of the vessel, length, breadth and depth is about 100m, 8m respectively.
SPB® tank is aluminum cargo tank, and has wooden blocks (wood support) on tank top and bottom. The tank is set on hull and supported by wood supports. Several supports of them prevent relative deformation of the tank to hull, those are anti-floating chock (AF Chock) for flooding, bottom transverse chock (BVT chock) and top transverse chock (TT Chock) for roll motion, and bottom longitudinal chock (BVL Chock) for surge motion and collision.
Bottom wood supports were arranged every frame for the other SPB® tanks which we had designed for LNG carriers, F-LNG, FSRU and so on. Though this SPB® tank in the bunkering vessel doesn’t need many supports due to smaller tank size with comparison to those we had designed, reduction of wood supports induces larger relative deformation between cargo tank and hull and reaction force concentration of wood supports from hull. We confirmed that the effect of relative deformation is safe enough by whole ship FE analysis.
In this paper, we show the design example of SPB® LNG tank for this bunkering vessel with the above rationalization.