In oil exploitation, carbon dioxide, hydrogen sulfide, and dissolved salts (mainly sodium chloride) can cause severe substantial corrosion to the pipelines. Additives such as corrosion inhibitors are one of the most viable solutions for dealing with corrosion problems arising from different process conditions in oil and gas production [1]. Typically, film former inhibitors are used on a large scale, and aliphatic diamines or imidazolines with long carbon chains are examples of effectiveness [2]. This study aims to evaluate the corrosion performance of quaternary imidazoline loaded on halloysite nanotubes for application in oil and gas production. The corrosion inhibitor efficiency (IE) of a quaternary imidazoline (IMD) in the AISI 1005 carbon steel at NaCl 3,5%(w/w) media was evaluated by electrochemical techniques. A three-electrode system was used to measure the linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). Firstly, after attaining a stable open circuit potential (OCP), measurement was made for pre-established immersion intervals: 2, 4, 6, 12, and 24h. The corrosion inhibition efficiencies (IE) were obtained from LPR and EIS results. Halloysite nanotubes (HNTs) were loaded with IMD, and successful loading was confirmed by UV-Vis analysis (Figure 1). Releasing behavior was observed by EIS for the first 24h of immersion at three different pHs (3, 7, and 9) and by UV-Vis. Results showed increased metal surface protection in the presence of the free corrosion inhibitor (non-loaded in HNT) and a corrosion rate decreasing with maximum inhibition efficiency of 85% (Table 1). EIS curves presented an increased capacitive arc and the appearance of a second time-constant for the free corrosion inhibitor condition (Figures 2and 3). UV-Vis revealed that IMD release was favored in acid conditions (Figure 4). EIS showed that corrosion protection increased with inhibitor release for all pHs (Figure 5), but mainly for basic conditions, it may be related to the fact that basic medium is less aggressive than the others

Subject
Electrochemical impedance spectroscopy, Inhibitor performance, Imidazolines, Sodium chloride, Acidity, Salt concentration, Corrosion inhibitors, Chemical engineering, Oil and gas production, Immersion, Corrosion protection, Stainless steel, Linear polarization resistance
Keywords:
corrosion inhibitor, quaternary imidazoline, nanocontainers
© 2023 Association for Materials Protection and Performance (AMPP) and ABRACO. All rights reserved. This work is protected by both domestic and international copyright laws. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without prior written permission. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP or ABRACO. Responsibility for the content of the work lies solely with the author(s).
2023
Association for Materials Protection and Performance (AMPP)
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