When producing hydrocarbons from an oil well, managing erosion of both surface and subsurface components caused by solids in the flow stream is critical to maintaining operations integrity in both land and offshore assets. Although component lifetime prediction has advanced in the past few decades, the prediction's accuracy remains a major oil and gas industry challenge. Current computational models only provide an initial erosion rate which is usually assumed constant until equipment failure. However, observed erosional rates vary as a function of time due to the geometrical changes caused by equipment material loss, which result in variations in solid particle impingement velocity [
This paper presents an implementation of an erosion dynamics model in ANSYS FLUENT, a commercial computational fluid dynamics (CFD) software, to capture the progression of transient erosion. The model has the capability to capture the effects of surfaces receding from erosion at each time interval. By dynamically adjusting these surfaces and recalculating the local flow conditions in the area, this method can predict new erosion rates for each time interval and achieve fully coupled geometry-flow-erosion interactions.
This new erosion dynamics model was validated against experimental data from both literature and physical testing, and was determined to have accurately captured the observed erosion trends over time in terms of location and magnitude. The model was then employed to study two real world applications: 1) in evaluating the erosion risk for a high-rate water injector, it predicted the evolution of damage to a coupler designed to connect different diameter pipes, and 2) in analyzing facility piping systems connected to an unconventional well, it predicted the transient erosion trend from proppant flowback, which allowed for pipe geometry optimization to increase in erosional life expectancy.
Logier, Jared (California State Polytechnic University) | Wang, Jason (California State Polytechnic University) | Villalpando, Obed (California State Polytechnic University) | Jalbuena, Alexander (California State Polytechnic University) | Ravi, Vilupanur A. (California State Polytechnic University)
ABSTRACTMolten salts have emerged as viable candidates for thermal energy storage in Concentrated Solar Power (CSP) applications. Candidate chloride salts offer the advantages of being readily available and stable at high temperatures, thus opening up the possibility for increased power generation efficiency. However, molten chloride salts are corrosive; therefore, proper materials selection for plant hardware is vital. Current CSP plants use stainless steels and nickel-base alloys as materials of construction because of the desirable combination of mechanical properties and corrosion resistance. In this research project, the focus was on the corrosion behavior of two different stainless steels (UNS S30400 and UNS S31600) and a carbon steel, i.e., UNS G10180. These were tested at 700°C in a molten NaCl-KCl-MgCl2eutectic salt in static air and flowing argon. Electrochemical techniques were used to characterize the corrosion behavior of these materials. The morphology of the attack was determined using scanning electron microscopy coupled with energy dispersive spectroscopy (EDS). X-ray diffraction was used to characterize the corrosion products formed on the surface of the substrate. Based on these results, the candidate salt was deemed to be unsuitable for this application. In addition, all of the candidate alloys had unacceptably high corrosion rates.INTRODUCTIONSolar energy is a rapidly expanding alternative to fossil fuels that is predominantly harvested through the use of photovoltaics (PVs). The functionality of PVs is restricted to the periods when direct sunlight is available. One method of overcoming this constraint to energy generation is through the use of concentrated solar power (CSP). CSP is emerging as an attractive alternative to PVs because of the persistence in providing energy to the grid during periods when the sunlight is absent. This is facilitated by storing energy in a heat transfer fluid (HTF).Molten salts have been identified as ideal heat transfer fluids in CSP applications because they contain many desirable thermal properties, e.g., high heat capacities, stability over a wide range of temperatures, etc. The Andasol plant in Spain and the Solano plant in Arizona currently use nitrate mixtures as heat transfer fluids.1 Stainless steels and nickel-base alloys are the materials of choice for molten salt containment in many current CSP plants because they provide sufficient corrosion resistance when exposed to nitrate salts, the currently preferred HTF.2 Chloride mixtures are a potentially attractive alternative because they offer higher thermal stabilities and are more economically viable than nitrates. However, molten chloride salts are corrosive, and therefore, proper salt & containment material selection are essential.