Application of Cryogenic Spill Control Techniques in Floating LNG

Abstract

Coral Sul FLNG is designed to produce, liquefy, store and transfer LNG and condensates directly at the offshore reservoir. Over 430 meters long, Coral Sul will be the first FLNG ever built to operate in ultra-deep waters, its wells are located 2000 meters below sea level. The vessel is currently under construction by Technip, JGC, Samsung Consortium (TJS) in South Korea for a joint venture led by Eni as operator and partners (ExxonMobil, ENH, GALP, KOGAS and CNPC). The main safety challenges for the FLNG technology, relate to the management of cryogenic spills on board and the protection of people and assets in a very congested environment. FLNG technology is introducing a set of new safety rules for the industry which are still under development by main international certification bodies. Today, the lack of industry standards regarding FLNG technology, and the congested nature of the installation, make the Risk Based Approach an essential step to validate the design and identify fit for purpose reduction measures. Coral project carried out several actions for Cryogenic Risk Management with the aim to: ensure safety of all the Personnel on Boardminimize the potential for escalation and maintain asset integrity. This Paper describes the Risk Based Approach followed for Coral FLNG project and describes some of the most important design safety measures implemented on board to manage cryogenic spills: Design of Drainage System and Overboard dischargeDesigned against the Risk of Rapid Phase TransitionActive Protection Methods: Water Curtains to protect hull sideImproved Coating Materials (combined effect Cryogenic Spill Protection + Passive Fire Protection) Suitable design of drainage system is a key safety aspect for the design of the FLNG, since it is essential to minimize the vaporization which can create dangerous flammable gas clouds on board. The solution proposed for Coral Sul FLNG is a combination of open gutters, sloped open channels and vertical pipes which allow the quick discharge overboard of accidental spills, minimizing the vaporization in congested areas. In proximity of overboard spillage points, water curtains are implemented to protect the hull side, and the effect of discharge is evaluated for rapid phase transition. Steel decks and structures must be protected against fractures that can follow accidental cryogenic spillages and lead to structural failures which put at risk lives and assets. Specific coating materials have been developed for the protection of decks, piping and equipment to avoid the escalation of any incident. These coatings provide combined protection against embrittlement and fire. Application of coating is done used RBA approach. Design of drainage system and coatings have been identified as technical novelties. A technology validation program has been put in place for Coral Project in order to assess the maturity of the new technologies.