A study was undertaken to determine the extent of corrosion damage on aluminum 3003 which is used in the main heat exchanger in air separation plants. The possible corroding species were Cl2, HC1, HOCl, Cl2O, NH2Cl, NHCl2, and NCl3; these compounds could come from chlorinated plant cooling water used in an air scrubbing tower upstream of the heat exchanger. A counter-current scrubbing tower simulating equipment in an air separation plant was used to produce an atmosphere containing the above volatile compounds. Specimens of aluminum 3003 and 3010, which were developed for their corrosion resistance, were placed in wet and alternating wet and dry conditions in the air stream above this tower. Studies show the primary specie causing corrosion was HOCl; evidence of NH2Cl was also present and thought to contribute to the corrosivity of the particular environment on the aluminum alloy surface. A thorough examination of the vapor-liquid equilibria for chlorine compounds was carried out to substantiate the findings. The results indicate total residual chlorine compounds carried over in the air stream were corrosive to aluminum 3003. In the concentrations of free chlorine employed in the scrubbing water, aluminum 3010 showed superior corrosion resistance.

Subject
Acids, Chemical compounds, Vapor pressure, Water, Ions, Aluminum, Condensates, Vapors, Acidity, Heat exchangers, Towers, Chlorine, Aluminum alloys
© 1981 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).
1981
Association for Materials Protection and Performance (AMPP)
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