A pressurized refreshed rotating cylinder rig is described that allows multiple measurements of corrosion rates to be made under controlled fluid flow conditions in hydrocarbon fluids such as crude oils or synthetic mixtures up to 400°C (750°F) and 70 bar (1000 psi). The use of the rotating cylinder allows corrosion data to be obtained using volumes of crude oils or crude fractions of the order of 10 liters per 24 hours, without the expense of a rig simulating full pipe flow and the hazard associated with the need to pump large volumes of hydrocarbons at high temperature. Good reproducibility is demonstrated in naphthenic acid corrosion studies. The applications to materials selection, inhibitor evaluation and crude blending to reduce corrosion from acid crudes are described, and the importance of using crude fractions that represent those that are formed at different stages in the distillation process to obtain data that can be used to predict corrosion rates at different locations in the refinery.
Keywords: crude oil, acid crudes, naphthenic acid, corrosion, flow effects, rotating cylinder, laboratory measurements