Research On Design And Analysis Of LNG Membrane-Type Containment System

The problem about environmental pollution is outstanding increasingly caused by traditional energy, so the clean energy of natural gas development become the focus of world energy strategic. As more natural gas energy was distributed in deep sea and small scattered sea. And then new development type about floating liquefied natural gas facility (FLNG) become the focus of research. However the cargo containment system is one of the important equipment of FLNG. But the capacity of the ship tank increased and no limited of filling level make the tank equipment very difficult to design and manufacture which will be used to store low-temperature liquefied natural gas. Meanwhile the structural safety of containment system is a key issue when it resists the sloshing impact load and is in the ultra-low temperature conditional. Therefore we study about the mechanical property and thermal insulation property of the containment system based on model test and finite element analysis.In the case of partial load, one of the biggest threat to the security of cargo containment system is the sloshing impact load. The large-scale sloshing model experimental method which can truly reveal the process of liquid sloshing in tank is the most reliable approach and method to determine impact loads. The size and form of sloshing impact load are analyze by advanced sloshing model test in this paper. And the effective sloshing impact load is designed using the most effective statistical fitting method for structural analysis. On this basis, the finite element model of containment system cross-section was established to carry out dynamic analysis to study the effect on the critical failure position by sloshing load and structure size parameters. Meanwhile the structure model of tank was established for steady-state analysis of heat conduction. The temperature distribution of the tank was analyzed with different boundary conditions. The boil off rate and the low temperature stress were calculated and the insulation capacity of cargo containment system was analyzed and checked. The research result can provide a reference and analysis basis for assessment and design of containment system of membrane tank.