Floating Lng Challenges On Cryogenic Spill Control

Abstract

Abstract Cryogenic spill on Floating LNG (FLNG) is one of the risks which need to be managed to avoid the potential embritllement and subsequent fracture of exposed unprotected steel work, as well as the possibility of large flammable cloud within the facility which may cause fire and explosion. For onshore LNG plants, guidance on spill control has been based on the widely used NFPA59A and EN1473.However, these guidelines are not directly applicable FLNG. With the absence of international rules directly applicable to this new concept, risk-based approach can be considered to determine the design. The challenge is how to control the cryogenic liquid spill in a congested installation when there are no proven robust existing installations for this application. Onshore practice is to collect the cryogenic liquid spill in an impoundment area. However, this practice is not suitable for offshore installation due to limitation in space and congested nature of FLNG facilities. In using risk based approach, the cryogenic spill is presumed to have a large extent due to two-phase jet caused by high pressure systems. Thus, a study and optimization for the cryogenic spill control design on the onset of the project is important. In this paper, there are several options that are considered during the design development on how to control the cryogenic spill in Floating LNG using risk analysis. The risk analysis method is widely used in offshore design but it also has limitations. Designing based on risk analysis with different possible options is also described, recognizing the strengths and weaknesses of each design option in terms of safety and operability. An observation of alternative approach rather than purely relying on risk analysis is also discussed in this paper.