Of approximately 148 "HF" alkylation units that have been licensed all over the world some 63 are operating in the United States. These range in size from a 800 bbl./day unit in Wyoming to a 28,400 bbl./day unit in Louisiana.1

Universal Oil Products (UOP) and Phillips Petroleum Company, the two companies that license "HF" alkylation units, tailor their plants to the needs of their customers. Roth UOP and Phillips units vary their hardware when varying capacity or varying the purpose of the unit.2,3

"HF" alkylation units are usually shutdown every two years for periodic maintenance. The shutdown procedure involves an alkylate flush followed by neutralization of the residual HF. The neutralization usually involves circulation of a solution such as potassium hydroxide until the process equipment has been made safe for entry and inspection.

Process equipment so neutralized would still contain corrosion products, scale and possibly trapped HF. Inspection and repair of such equipment would be considerably slowed down by these contaminants. Iron fluoride scale has made removal of heat exchangers from their shells difficult and sometimes impossible.

The cost of any turnaround is dependent on being able to adhere to the Critical Path Schedules. Process equipment that is difficult to inspect, much less repair, and heat exchanger bundles that refuse to leave their shell cause havoc with turnaround schedules.

A well planned chemical cleaning will remove iron fluoride, use residual HF to enhance removal of corrosion products and leave a clean, safe, and predictable unit which will adhere to turnaround schedules and reduce turnaround cost.

An "HF" alkylation unit demands care, planning and attention to detail. The refinery is rewarded with an easy to operate and economical producer of high octane gasoline. Chemical cleaning requires the same care, planning and attention to detail to produce an economical and predictable turnaround. It follows that for an "HF" alkylation unit, well planned chemical cleaning is as natural as it is necessary.

Subject
Acids, Fluorides, Chemical cleaning, Iron, Inspection, Neutralization, Corrosion products, Solutions, Equipment, Towers, Hydrofluoric acid alkylation, Maintenance, Cleaning
© 1984 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).
1984
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.