Simultaneous Hydrate and Corrosion Inhibition with Modified Poly(vinyl caprolactam) Polymers

Abstract

Corrosion and unwanted gas hydrate formation in subsea flowlines are two of the major issues that the global gas industry faces when transporting natural gas. Gas hydrates can cause severe blockages due to the formation of hydrate plugs that block the flow. Corrosion issues lead to significant economic loss in terms of prevention and repair. To manage these issues, hydrate and corrosion inhibitors are injected separately to subsea flowlines. However, there are often compatibility issues that negatively impact their performance as a result of surface and molecular interactions. The aim of this study is to tackle this compatibility problem by developing single polymer molecules that simultaneously prevent hydrate formation and inhibit corrosion. The resulting materials are termed as kinetic hydrate and corrosion inhibitors (KHCIs). The molecules are designed and assembled using key structural motifs that are known kinetic hydrate inhibitor s (KHIs) and corrosion inhibitors. Specifically a KHI base polymer is modified with corrosion groups using a series of highly efficient chemical reactions. This method generates controlled libraries of inhibitors with the same molecular weight (Mw), Mw distribution, end groups, and composition along the chain. This control allows for accurate interpretation of the effect of the structural group on the hydrate and corrosion inhibition. This is a proof-of-concept study that can be expanded with further performance testing and modifications of polymer structure.