Effect of Powders and Corroded Steel on Methane Hydrate Formation

In the context of flow assurance for energy production infrastructure, impurities such as corrosion byproducts from carbon steel (CS) pipes or iron carbonate particles detached from protective corrosion layers may enter gas–water systems, potentially promoting hydrate formation. This study investigates the impact of metal oxide and carbonate powders, as well as corroded pipeline walls, on methane hydrate nucleation and initial growth rates using high-pressure stirred automated lag time apparatus (HPS-ALTA). Iron carbonate (FeCO3), magnesium carbonate (MgCO3), and magnesium oxide (MgO) powders were tested, with all particles showing promotion of hydrate nucleation, reaching a maximum effect at approximately 1.2 wt % for FeCO3 and MgO, and 0.1 wt % for MgCO3. FeCO3 demonstrated the strongest promoting effect, reducing mean subcooling by 5 K, with no further increase in promotion beyond this concentration. Corroded carbon steel walls showed no significant difference in promoting nucleation rate compared to noncorroded walls. Nucleation rates, analyzed using the hazard function within the classical nucleation theory (CNT) framework, revealed that the powders mainly promote nucleation by increasing available nucleation sites. This work fills a key knowledge gap, offering new insights into how field infrastructure degradation may unintentionally exacerbate hydrate formation challenges in energy production operations.