(438c) Application of Computational Fluid Dynamics Simulation in Study of Amine Absorber at Off-Shore Operation

Crude natural gas contains acid gases such as CO₂ and H₂S. The acid gases must be removed to achieve clean natural gas for the wide usage. One of the most popular processes used to remove the acid gases is the amine absorber. In offshore operations, the gas processing is commonly carried out on the FPSO (Floating, production, storage and off-loading) unit located near oil wells. The absorber efficiency on FPSO may be deteriorated because of ocean wave interaction.

This work aims to study the effect of ship tilting and motion on the acid gas removal efficiency in an amine absorber with structured packing, by using CFD (Computational fluid dynamics) simulation. First, a porous media CFD model was developed in the framework of Eulerian two-fluid flows to mimic fluid behaviours inside structured packing. Parameters of the CFD model were adjusted to fit experimental data in two cases of vertical standing and static tilting. Second, CFD simulation was used to improve the design of a liquid redistributor subjected to the motion. The results in the effective interfacial area, CO₂ concentration profile and uniformity index were compared for three cases of vertical standing, ship tilting and ship motion.