The results of destructive examinations of uncooled and air-cooled specimens removed from an experimental coal-fired atmospheric limestone fluidized bed after exposures of about 500, 1000 and 2000 hours are reported. The corrosion rates for tventy-three different materials were determined and these are to be used in conjunction with the results of samples removed from an in-bed heat exchanger to determine the materials to be used for the design of a commercial fluidized bed air heater. The overall test conditions, sample descriptions and rankings of the alloys tested are presented. Some generalizations concerning alloy composition are presented. Apparently alloys containing high nickel and aluminum contents have poorer corrosion resistance and arc not recommended for this application.

Plasma and flaae sprayed coatings of FeCrAlY and CoCrAlY were tested but measurements of their corrosion were not possible and their adherence to substrates of TP 304H S5 and alloy 800H was poor and would need to be improved for this application.

The corrosion rates of test velds were generally greater than many of the alloys and either other weld compositions or larger thicknesses would have to be used for this application.

Subject
Materials, Corrosion resistant alloys, Corrosion rate, Probes, Nickel based alloys, Tubes, Thermocouples, Penetration, Heat exchangers, Fluids, Coal, Oxygen, Samples
Keywords:
atmospheric fluidized bed, corrosion, air heater, stainless steels, nickel base alloys, cobalt base alloys, bimetallic tubing, coatings, velds
© 1991 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).
1991
Association for Materials Protection and Performance (AMPP)
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