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Title: Phase relationship in coal ash corrosion products

Abstract

The corrosion of heat transfer surfaces in coal-fired utility boilers is a major concern to the efficient operation of these units. Despite the importance of the corrosion there has been limited research on the relationship between the ash components on the tube surface and the interactions and reactions between the various components and the steel surface. Mechanisms such as molten phase corrosion, sulfidation, and high temperature oxidation have been identified as leading to extensive wastage oftube metal. However, while the corrosion process can be identified using techniques such as metallography and x-ray diffraction there is limited insight into the role ofthe coal mineralogy and ash deposits on the surface in the corrosion process. This paper describes research into the formation of molten or sernimolten phases within ash deposits which are associated with corrosion of superheater and reheater fireside surfaces. For example, the phases potassium pyrosulfate (K{sub 2}S{sub 2}O{sub 7}) and potassium aluminum sulfate (K{sub 2}Al{sub 2}SO{sub 7}) have been determined by x-ray diffraction to be present in deposits where fireside corrosion has occurred. However, both these phases are not directly derived from coal minerals or the common matrix observed in ash deposits. The examination of the reactions and interactions withinmore » deposits which result in the formation of these and other phases associated with corrosion will be discussed in the paper.« less

Authors:
 [1]
  1. DB Riley, Inc., Worcester, MA (United States)
Publication Date:
OSTI Identifier:
430300
Report Number(s):
CONF-960376-
Journal ID: ACFPAI; ISSN 0569-3772; TRN: 97:000004-0028
Resource Type:
Journal Article
Journal Name:
Preprints of Papers, American Chemical Society, Division of Fuel Chemistry
Additional Journal Information:
Journal Volume: 41; Journal Issue: 2; Conference: Spring national meeting of the American Chemical Society (ACS), New Orleans, LA (United States), 24-28 Mar 1996; Other Information: PBD: 1996
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; COAL; MINERALOGY; DEPOSITS; CHEMICAL COMPOSITION; BOILERS; CORROSION PRODUCTS; HEAT TRANSFER; OXIDATION; SULFIDATION; POTASSIUM SULFATES; ALUMINIUM SULFATES

Citation Formats

Kalmanovitch, D. Phase relationship in coal ash corrosion products. United States: N. p., 1996. Web.
Kalmanovitch, D. Phase relationship in coal ash corrosion products. United States.
Kalmanovitch, D. 1996. "Phase relationship in coal ash corrosion products". United States.
@article{osti_430300,
title = {Phase relationship in coal ash corrosion products},
author = {Kalmanovitch, D},
abstractNote = {The corrosion of heat transfer surfaces in coal-fired utility boilers is a major concern to the efficient operation of these units. Despite the importance of the corrosion there has been limited research on the relationship between the ash components on the tube surface and the interactions and reactions between the various components and the steel surface. Mechanisms such as molten phase corrosion, sulfidation, and high temperature oxidation have been identified as leading to extensive wastage oftube metal. However, while the corrosion process can be identified using techniques such as metallography and x-ray diffraction there is limited insight into the role ofthe coal mineralogy and ash deposits on the surface in the corrosion process. This paper describes research into the formation of molten or sernimolten phases within ash deposits which are associated with corrosion of superheater and reheater fireside surfaces. For example, the phases potassium pyrosulfate (K{sub 2}S{sub 2}O{sub 7}) and potassium aluminum sulfate (K{sub 2}Al{sub 2}SO{sub 7}) have been determined by x-ray diffraction to be present in deposits where fireside corrosion has occurred. However, both these phases are not directly derived from coal minerals or the common matrix observed in ash deposits. The examination of the reactions and interactions within deposits which result in the formation of these and other phases associated with corrosion will be discussed in the paper.},
doi = {},
url = {https://www.osti.gov/biblio/430300}, journal = {Preprints of Papers, American Chemical Society, Division of Fuel Chemistry},
number = 2,
volume = 41,
place = {United States},
year = {Tue Dec 31 00:00:00 EST 1996},
month = {Tue Dec 31 00:00:00 EST 1996}
}