This paper reviews corrosion control in crude column overheads by automatic neutralisation of acid components in the overhead stream.

Tailwater pH is a convenient indicator of the corrosivity in the overheads environment. However, corrosion rates can seemingly be out of proportion with tailwater pH and this paper examines the relationship between pH and the overheads dew point environment where corrosion is likely to be most severe. It is shown that concentration of HCl, H2S and CO2 in the overheads stream and the neutraliser chemical type all effect this relationship and the choice of pH set point. It is demonstrated by both industrial and pilot plant data that tailwater pH needs to be controlled to within fine limits (± 0.2) of the chosen set point to give maximum protection. The development of a successful automatic system to achieve this is described.

Industrial case histories are given in which automatic pH control systems are reliably controlling tailwater pH to within those limits and where corrosion of overheads heat exchangers is reduced.

Subject
Acids, Water, Corrosion rate, Iron, Water dew, Refineries, Ammonia, Acidity, Amines, Crude, Dew point, Upset, Chlorides
© 1982 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).
1982
Association for Materials Protection and Performance (AMPP)
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