Modeling underwater penetration of LNG carrier

Authors

  • John L. Woodward

    Corresponding author
    1. Baker Engineering and Risk Consultants, Inc., 3330 Oakwell Court, Suite 100, San Antonio, TX 78218
    • Baker Engineering and Risk Consultants, Inc., 3330 Oakwell Court, Suite 100, San Antonio, TX 78218
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Abstract

An underwater breach of a tank in a double-hulled LNG carrier poses several challenging questions to be addressed by an adequate model. This article describes a model that accounts for the following phenomena: (1) LNG tank vapor space pressure decreasing by the piston effect of outflow (the effect a decreasing water level pulling down the pressure); (2) LNG evaporation in the hull space and vapor outflow through the outer breach; (3) LNG outflow and gas inflow to the LNG tank at the inner breach; (4) Ice formation by LNG evaporative cooling. The model does not allow for localized ice build up at the inner breach constricting flow. Predictions show tank pressure, LNG outflow rates, water inflow rates over time, the duration of the event, and total LNG losses. Losses are shown to be considerably less with double-hull than with single hull construction. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2008

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