Offshore loading systems provide products to tankers through marine hoses. The marine hoses, along with the rest of the loading system, can experience surge pressures initiated by a valve closure. In this paper, surge analysis studies are carried out for two common configurations of “tandem” and “buoy” loading systems. The results show much lower surge pressures in marine hoses than those in carbon steel pipes due to the different elasticities of their material. For the “tandem” configuration, the results show that loading rates and valve closure time play a key role in the final hose pressure due to overall transient pressures dominated by potential surge pressures. For operations featured in the “buoy” configuration, where line pack pressure dominates the overall transient pressure, the results show that timely cutoff of the flow by closing a valve at the pipeline end manifold (PLEM) is imperative.
An offshore loading system, which provides bulk liquid to a tanker through marine hoses, could experience surge pressures throughout the system, as well as within the marine hose strings, due to a valve closure. Such surge incidents can result in the rupture of the marine hoses, or damage to the tanker piping or a buoy with consequent pollution of the environment [1]. Despite the wide range of applications of marine hoses throughout industry, the surge pressure phenomena in marine hoses has not been well studied.
When a bulk liquid is loaded from a floating production storage and offloading (FPSO) vessel to a tanker through marine hoses, the loading system operates in a “tandem” configuration, where potential surge pressures are dominant upon closure of a valve. When the liquid flow is delivered from an onshore terminal to a tanker through seabed pipelines, buoys, and marine hoses, the loading system is considered to operate in a “buoy” configuration where line packing becomes a challenge in the transient pressures triggered by a valve closure. Regardless of the tandem or buoy offshore loading configurations, the marine hoses attached to the systems will contract and expand significantly to interfere with the pressure waves due to their high elasticity.
