(358g) Study on Wave Motion Effects on FLNG Mixed Refrigeration Process Via Integrated CFD and Process Simulations

Floating liquefied natural gas facility (FLNG) has been studied since 1970, but makes very low progress until recent years, Compared with the traditional liquefaction facilities, FLNG faces several challenges, such as it has only very limited space to contain many necessary units; meanwhile, sea wave motions will bring negative impacts on the stability and safety of the onboard manufacturing process. During the FLNG liquefaction process, the mixed refrigerant (MR) separator would easily be affected by the wave motions, so that the separated vapor stream would have some liquid entrainment, which would further degrade the MR refrigeration performance. Hitherto, there are few researches on how sea wave motions influence the MR process.

In this study, the dynamic effects of process under wave motion was investigated by utilizing both computational fluid dynamics (CFD) and process dynamic simulation, a commercial CFD tool was applied and a multiphase model was developed to simulate the fluid moving and separation efficiency within the MR separator. A user-defined function (UDF) has been developed in C and hooked with the solver to model the wave motion and liquid sloshing. Based on the CFD simulation, MR separator efficiency data has been obtained and coupled with a process simulation model to quantitatively study the impact of refrigeration system performance. This study could help future studies on process optimization to improve process design, process controllability, and safety of the FLNG liquefaction process.