(141a) CFD-Based Probabilistic Explosion Hazard Analysis As an Early Tool to Improve FLNG Design

Process areas on floating LNG facilities are typically designed to be very compact, due to the high costs of “floating real estate”. Given the high congestion levels of FLNGs, explosion design accidental loads (DALs) can become very large and are very sensitive to the layout of piping and equipment, the size of safety gaps, specifics of the liquefaction process, etc. For these reasons, the analysis of explosion hazards on FLNGs is a critical step that should accompany the facility development from the very earliest design phase. This paper will discuss how a probabilistic explosion hazard analysis methodology based on computational fluid dynamics (CFD) modeling can be used to optimize the layout of an FLNG facility with respect to DALs. The methodology uses a detailed 3D model of the FLNG geometry (down to 1-2 inch pipe diameters) within which gas dispersion and vapor cloud explosion scenarios are simulated using a CFD tool; leak rate probability data and the TDIIM ignition model are then used to calculate probability of exceedance curves and to determine the DALs. The paper will present results from a study, which compared the effectiveness of a number of design alternatives, such as:

• Grated vs. solid decks;
• Weak barriers vs. blast walls;
• Safety gap size;
• Different liquefaction processes.

The paper will demonstrate how this methodology can provide FLNG designers with critical safety-related design implications previously not available.