Structural analysis of an lng carrier mooring and offloading connector

PROBLEM OVERVIEW

• Feasibility study of a system based on the principle of Multibore Quick Connect/Disconnect Coupler, that, besides the connections of pressure lines, guarantees the "structural" connection between LNG and loading arm
• The connector is split into two halves: one (the upper) lives on the loading arm, the other (the lower) lives on the LNG carrier; the two halves are connected during the offloading operations
• In the in-service condition, the Connector operates with internal fluid at -162 °C (problem of resilience of materials to employ) and design pressure of 19 barG)
• In the in-service conditions the Connector has to withstand the actions due to the dynamic of the system given by LNG-carrier/offloading-arm (and relevant yoking system, if any)

NUMERICAL APPROACH

• Development of finite element models and structural analysis of QC/DC clamping mechanism and pressure parts (valve bodies)
• Development of finite element models and structural analysis of QC/DC structural components (upper half, lower half)
• Study over the temperature distribution (-162 °C into pressure lines) and over the insulation problems
• Structural analysis and verifications of pressure retaining components for design conditions
• Fatigue verifications of structural and pressure retaining components

RULES

• Pressure Parts (4 lines 16” ND - 19 bar design pressure): ASME VIII Div. 2
• Structural Parts (QC upper half, QC lower half): DNV – Rules for the Classification of Mobile Offshore Units – Part 3, Chpt 1 (reference stresses: 0.6Fy and 0.8Fy)

CUSTOMER

MIB - Italy

 

STRUCTURAL ANALYSIS OF
AN LNG CARRIER MOORING AND OFFLOADING CONNECTOR

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