Methanol is commonly used in the oil industry as a thermodynamic hydrate inhibitor. In world regions with extended winter seasons, significant amounts of methanol are injected into wells and pipelines. Previous studies have demonstrated that the presence of methanol in sour conditions can lead to higher corrosion rates and the increased susceptibility to sulfide stress cracking (SSC) in pipeline steel. Another problem is oxygen intrusion by dissolution in methanol, increasing corrosion rates and potential for localized corrosion.

This paper studies the effect of oxygen in methanol on the structures and growth kinetics of iron sulfide scales. Gravimetric weight analysis was used to evaluate the corrosion mechanisms and rates. Scanning Electron Microscope/Energy Dispersive X-ray Spectrometry (SEM/EDX), Optical Microscope and X-ray Diffraction (XRD) were used to analyze the scale.

Subject
Scanning electron microscopy, X-ray diffraction, Mackinawite, Corrosion rate, Metal surfaces, Iron sulfides, Corrosion products, Corrosion scales, Fluids, Oxygen, Methanol, Corrosion coupons, Localized corrosion
Keywords:
methanol, oxygen, iron sulfide, sour gas, localized corrosion, carbon steel
© 2007 Association for Materials Protection and Performance (AMPP). All rights reserved. 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 the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2007
Association for Materials Protection and Performance (AMPP)
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