Spill Control Systems on Floating LNG Topside

Onshore LNG facilities refer NFPA 59A, EN 1473, API 2510, and API 2510A for LNG and LPG (i.e., flammable cryogenic) spill control systems and provide the flammable cryogenic spill control system, such as LNG / LPG spill containment, in order to properly control the flammable cryogenic spill and mitigate the risk of larger fire and explosion due to uncontrolled flammable cryogenic spill.

Floating LNG Topside (i.e., Offshore LNG facilities) also has the same risk as onshore LNG facilities, and it is also important to provide proper flammable cryogenic spill control system. The codes and standards for the flammable cryogenic spill control system specify requirements of slope, drain path, spill containment, and safety distance between spill containment and process equipment, however Floating LNG Topside area is limited, therefore it is difficult to provide sufficient safety distance for the flammable cryogenic spill containment system if it is installed on Floating LNG Topside. As the result, it is concluded that the flammable cryogenic spill control system on Floating LNG Topside should dispose of the flammable cryogenic spill overboard as soon as possible from safety point of view. However there is the difficulties that there are process units which handle the both, the cryogenic liquid and the environmental pollutants (such as heavy hydrocarbons), and the flammable cryogenic spill control system may also collect environmental pollutants spill and dispose of the environmental pollutants overboard. Furthermore, if the environmental pollutants spill control system is also provided on Floating LNG Topside, there is risk of the flammable cryogenic spill ingress to the environmental pollutants spill control system (it is not designed for the cryogenic spill) which results in the secondary accidents.

This paper proposes the flammable cryogenic spill control system for Floating LNG Topside which disposes of the flammable cryogenic spill overboard. In addition, this paper shows the flammable cryogenic spill control system and the environmental pollutants spill control system for the process units which handle the both, the cryogenic liquid and the environmental pollutants, from safety and environmental point of view.

Keywords: Floating LNG, Spill Control System