ARRANGEMENT FOR MINIMIZING THE EXPLOSION POTENTIAL IN MOORED TURRETS FOR HYDROCARBON STORAGE VESSELS

摘要

An improved of connection of a disconnectable spider buoy (24) to an internal turret (14) of a floating production storage and offloading vessel is disclosed. Risers (30) from subsea wells are connected by quick disconnect/connection devices (38) to pipes (36) which run through the turret (14) and then via a product swivel (100) to lines leading to storage tanks on the vessel. A structure is provided to create an enclosed space (46) to enclose the connection devices (38) at the top of the spider buoy (24). A ventilation shaft (52) runs from the enclosed volume to atmosphere via the top of the turret (14). A forced air line (48) is provided into the enclosed space for ventilating the space (46) via the ventilation shaft (52) during normal operations. If a gas leak is sensed in the enclosed space (46), the forced air line is closed. The small volume which surrounds the connection devices (38) quickly fills with hydrocarbon gas to produce a high gas/air ratio in the enclosed space (46) which greatly reduces the danger of explosion.