Thermal Transient Control and Safety Validation During LNG Tank Cooldown Before First Marine Bunkering Operation

This poster provides a technical overview of the safety framework implemented during the initial thermal conditioning of an LNG storage tank installed on a dual-fuel Ro-Ro vessel prior to its first bunkering operation. The procedure, carried out at Damen Shipyard on 2 May in Romania, consisted of a controlled and progressive cooldown sequence designed to prepare the cryogenic system for LNG introduction while minimizing thermal gradients and mechanical stress. Vaporized and liquid nitrogen were employed in successive stages to gradually decrease tank and pipeline temperatures under strict operational supervision.

Continuous monitoring of temperature evolution, pressure stabilization, and vapor management was conducted to ensure structural integrity and prevent unintended releases. Special consideration was given to the routing, insulation, and secure positioning of cryogenic transfer hoses in order to eliminate the risk of contact with heat-sensitive structural elements of both the vessel and the quay infrastructure. Compliance with the International Code of Safety for Ships Using Gases or Other Low-Flashpoint Fuels (IGF Code) guided all operational decisions and safety precautions.

The poster outlines the principal technical phases of the cooldown procedure, the environmental protection measures adopted, and the risk-mitigation strategies applied throughout the operation. The documented experience contributes to current knowledge on LNG vessel commissioning practices and offers practical guidance for shipyards conducting pre-bunkering preparations in locations without permanent LNG terminal installations.