Bed materials obtained from several operating atmospheric pressure, fluidized-bed combustors (FBC)s were characterized to determine physical and chemical differences that may be responsible for causing excessive wear of in-bed evaporator tubes. The two main controlling parameters identified were quartz content and quartz particle size. In addition, the chemical constituents of some coals led to the formation of surface coatings on bed particles that may increase the surface hardness, or may serve to blunt hard or angular particles. The mechanism of formation of such coatings is not understood. Based on these results, some guidelines were formulated for minimizing or avoiding accelerated wastage in fluidized-bed combustors. Nevertheless, the results of comparisons of particle size distribution, mineralogy, hardness, chemical composition, and microstructure indicated that the wear potential of a bed consisting of a mixture of different types of particles cannot, at present, be deduced from a knowledge of the wear potential of individual particles.

Subject
Wear, Coatings, Materials, Sand, Tubes, Surface hardness, Quartz, Meshes, Wastage, Surface layers, Ash, Coal, Hardness
© 1994 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).
1994
Association for Materials Protection and Performance (AMPP)
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