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Title: High temperature degradation by erosion-corrosion in bubbling fluidized bed combustors

Heat-exchanger tubes in fluidized bed combustors (FBCs) often suffer material loss due to combined corrosion and erosion. Most severe damage is believed to be caused by the impact of dense packets of bed material on the lower parts of the tubes. In order to understand this phenomenon, a unique laboratory test rig at Berkeley was designed to simulate the particle hammering interactions between in-bed particles and tubes in bubbling fluidized bed combustors. In this design, a rod shaped specimen is actuated a short distance within a partially fluidized bed. The downward specimen motion is controlled to produce similar frequencies, velocities and impact forces as those experienced by the impacting particle aggregates in practical systems. Room temperature studies have shown that the degradation mechanism is a three-body abrasion process. This paper describes the characteristics of this test rig, reviews results at elevated temperatures and compares them to field experience. At higher temperatures, deposits of the bed material on tube surfaces can act as a protective layer. The deposition depended strongly on the type of bed material, the degree of tube surface oxidation and the tube and bed temperatures. With HCl present in the bed, wastage was increased due to enhanced oxidationmore » and reduced oxide scale adherence.« less
Authors:
; ; ;
Publication Date:
OSTI Identifier:
826095
Report Number(s):
LBNL--51069
TRN: US200424%%437
DOE Contract Number:
AC03-76SF00098
Resource Type:
Conference
Resource Relation:
Conference: International Symposium on High Temperature Corrosion on Energy Related Systems, Angra dos Reis (BR), 09/01/2002--09/04/2002; Other Information: PBD: 22 Apr 2003
Research Org:
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
Sponsoring Org:
USDOE Director. Office of Energy. Office of Basic Energy Sciences (US)
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; 36 MATERIALS SCIENCE; ABRASION; CORROSION; DEPOSITION; DESIGN; FLUIDIZED BEDS; FLUIDIZED-BED COMBUSTORS; OXIDATION; OXIDES