Lifetime prediction of valves subjected to impact erosion

Research is being carried out at Politecnico di Milano regarding the impact erosion in valves, the ultimate aim being the development of models for predicting the useful life-time of devices in oil fields with sand production. This has been done in the context of the project E.P.I.C.O. (Erosion Prediction In Control Operation), supported by ENI S.p.A. The goal of the project has been achieved through a multi-stage process involving Computational Fluid Dynamics and experimental testing. Firstly, the characterization of the erosion behaviour of the materials of the valves was provided through slurry jet impingement tests. The outcomes of numerical simulations, performed following the standard, well-established approach involving Eulerian-Lagrangian modelling of the liquid-particle flow and application of an algebraic erosion model, were compared against the laboratory data. This allowed proper definition of the erosion prediction models and assessment of their reliability for the flow conditions of interest. Secondly, the developed models were validated by the reproduction of the erosion tests on the actual devices performed in a dedicated slurry flow loop. The models proved capable in estimating the location of the erosion hotspots and the erosion rate of the most vulnerable valve components. Thirdly, a number of virtual experiments of valve erosion were numerically performed for different operating conditions (that is, valve opening, type of abrasives, and fluid dynamic conditions). Fourthly, models for useful life-time predictions have been developed based on the collected results. This approach has been applied to two different devices, namely a cage and sleeve choke valve and a gate valve. The good results obtained so far opens promising perspectives for the continuation of this research.