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Proposal Joined Industry Project (JIP). Full-scale verification of sloshing forces in membrane LNG tanks. Singapore, 31 March 2004. Source: Internet. Why new project?. Demand for LNG grows
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Proposal Joined Industry Project (JIP) Full-scale verification of sloshing forces in membrane LNG tanks Singapore, 31 March 2004
Source: Internet Why new project? . • Demand for LNG grows • the industry is racing to explore new gas fields, prepare production sites and plan new transport infrastructure • part of this development involves floating production and storage installations, with the application of membrane containment systems
Source: Internet Why new project? .. • Membrane containment systems have been used in LNG carriers for decades and have an outstanding safety record • The conditions of planned installations differ, however, from those of present carriers
Why new project? ... • A combination of continuous sea action and partially filled tanks may result in significant sloshing forces on the containment system • In LNG carriers these forces are being minimised by fully filled cargo tanks and (off)loading in sheltered areas • Several Classification Societies approved Membrane Systems for all filling levels
Why new project? .... • Sloshing is a popular research domain what results in many often contradictory results • Extensive discussion within the LNG industry about the issue of partial tank fillings • This discussion, justified or not, reflects the industry concern about this issue • Time for joined clarification and verification
Conclusion . • The verification of sloshing forces in partially filled membrane tanks is considered crucial as an “enabling technology” for offshore LNG developments • Alternative systems are (being) developed • CNG / PNG - Compressed / Pressurised Natural Gas • GTL - gas to fluid • SPG - self supporting stainless steel tank
State of the art . • Present methods to predict sloshing forces use model tests and numerical calculations • Both methods involve uncertainties • the fluid-structure interaction complicates the prediction • Full-scale verification is limited • AZURE project demonstrated feasibility of LNG offshore using membrane technology
Source: Internet Numerical challenges . • modeling of elastic containment system and supporting structure • modelling of 2-phase flow with boiling surface & saturated vapor • error accumulation during long simulations (3 hour) • local pressures badly conditioned • still CPU intensive
Source: Internet & MARIN Testing challenges . • modeling of elastic containment system and supporting structure • modeling of 2-phase flow with boiling surface & saturated vapour • modeling of fluid properties (surface tension) • determination of design pressures (scale effects)
Questions to be answered . • How is the sloshing phenomenon in real LNG tank and real sea conditions? • What are actual ship’s motions when sloshing appears? • What is the associated response of the containment system?
How ? . • Different options have already been investigated • a proper, timely, feasible and affordable verification is: Monitoring of an LNG carrier
Source: Internet Project challenges . • partial tank filling not used • (monitoring of tank top area) • long monitoring campaign • pressure measurement • free surface measurements • low temperature -162°C • data reduction/triggering
Project phases and tasks . • Phase I • sensor development • monitoring system design • ship selection • Phase II • Instrumentation • Monitoring • Verification (high filling) • Extrapolation (law filling)
Ship primary stresses Wave radar Ship motions DGPS Link to DCS Strains in containment system Optional pressure measurement free surface measurement Source: Internet Monitoring .
Source: Internet & MARIN Verification . • Model testing and numerical simulation • Use of measured tank fillings and measured ship motions • Extrapolation to different tank fillings
Steering Committee (Chairman) Participants Project Manager - MARIN Task 1 Task 2 Task 3 Task 4 Task 5 Phase II Phase I WG 1 - Sensors WG 2 - System design and approval WG 3 - Instrumentation WG 4 - Monitoring WG 5 - Verification & Extrapolation Project Organization
What next? . • Publicity • Collecting JIP partners • Kick off meeting • JIP proposal, agreement & subsidy • Collecting JIP participants • Start Phase 1
Project data .. • Start Phase I - 2004 • Project duration 4 years • Estimated annual fee 45kEuro • Contact person Mirek Kaminski • m.kaminski@marin.nl • +31 317 493 238