Coal ash deposits: Effects on tube wastage

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:256998

Kalmanovitch, D ^[1]

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1. Riley Stoker Corp., Worcester, MA (United States)

In recent years there have been major advances in the analysis, characterization, and modeling of coal ash deposition processes in utility boilers. The focus and thrust of these efforts has been to establish or predict the effect of the ash on heat transfer, back-pass fouling and pluggage, and slag falls. An area which has seen little attention to date has been the effect of the ash characteristics on corrosion processes. Corrosion of tubes such as superheater and reheater tubes leads to forced outages due to failure, increased maintenance and inspection costs, and the need for wholesale component replacement. Utilities need to understand the potential effects of a given fuel choice on the fireside wastage rates. The purpose of the paper is to illustrate the applicability of the recent developments in ash deposition modeling and characterization on the understanding and prediction of coal ash corrosion. Methods which show the difference between protective or passive deposits and corrosive deposits will be demonstrated. In particular, the application of scanning electron microscopy (SEMPC) to the characterization of corrosion interfaces will be shown. This technique is a powerful tool to determine both the phases present at an interface but also the extent of interaction between the deposit and the pressure part components. The extensive data can be used to establish corrosion rates at various temperatures. This information can then be used as critical input into remaining life analysis programs.

• OSTI ID: 256998
• Report Number(s): CONF-950952--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ASHES
BOILERS
CHEMICAL ANALYSIS
CORROSION
CORROSION PRODUCTS
CORROSIVE EFFECTS
DEPOSITION
DIAGNOSTIC TECHNIQUES
FOULING
MATHEMATICAL MODELS
PHASE STUDIES
SUPERHEATERS