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 inhibitors (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.

Performance of Waterborne Polyurethanes in Inhibition of Gas Hydrate Formation and Corrosion: Influence of Hydrophobic Fragments

“…In addition, two more advantages of the developed inhibitors should be noted. (1) A positively charged fragment of a protonated tertiary amine resembling quaternary ammonium salts [38,39] may provide antiagglomerant properties to the synthesized compounds; and (2) the negatively charged fragment imparts the properties of barrier corrosion inhibitors to polymers due to the ability to adsorb on the metal surface [5,14,27]. In this work, we introduced additional hydrophobic groups into the structure of polymers by replacing monoethanolamine with N-substituted diethanolamines during polymerization.…”

“…Ionic liquids, amino acids, and biopolymers (including modified ones) are considered in the literature as dual-function inhibitors (gas hydrate and corrosion inhibitors; GHCI) [11,12]. Typical kinetic hydrate inhibitors (KHIs) have anti-corrosion activity as well [13][14][15].…”

Influence of Hydrate Formation and Concentration of Salts on the Corrosion of Steel 20 Pipelines

“…Studies [15,17] have shown an increase in the level of localization of corrosion processes, but no explanation for this phenomenon has been provided. In general, most of the results reported in the literature describe hydrate formation during offshore gas [4,23,25] and gas transportation by offshore or onshore pipelines [9,16,20]. Mathematical models of corrosion effects of gas hydrates [1,2,3,6,21,22,24] do not take into account the effect on the metal or passive films of the hydrate itself, but only the pH of the medium or the concentration of CO2 in the gas.…”

Research on the Preparation and Anticorrosion Properties of EP/CeO2-GO Nanocomposite Coating

“…However, as an important part of construction materials, the metal materials are bounded to serve in the complex environments, such as acid rain [ 1 ] and salt [ 2 ]. According to previous research, the direct economic loss caused by metal corrosion is as high as 250 million us dollars every year [ 3 , 4 ]. Thus, corrosion protection of metal materials is of particular importance.…”