Arrangement for minimizing explosion potential in moored turrets for hydrocarbon storage vessels

摘要

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