Temperature dependence of steel wastage in a bubbling fluidized bed simulator
- Lawrence Berkeley Lab., CA (United States)
- Electric Power Research Inst., Palo Alto, CA (United States)
Tubes within bubbling fluidized bed combustors have in many instances suffered wastage. The wastage can be quite high at temperatures near 300 C, but it typically shows an abrupt decrease at approximately 400 C. Superheater tubes that operate at higher temperatures generally do not experience wastage. It is widely believed that this decrease in wastage with temperature is due to the development of a continuous oxide layer that protects the metal substrate by virtue of its hardness and resistance to spalling. In this study, the temperature effect is examined using a wear rig specially designed to simulate the impact conditions relevant to in-bed tubes. It was discovered that wastage for mild steel can decrease from a relatively high value to essential zero within the temperature range of 400 to 430 C. This decrease was attributable not to the presence of an oxide scale but to the development of a protective deposit layer. The deposit consisted of an agglomeration of submicron bed material particles. The submicron dust is created through the normal attrition process and it tends to form an adherent coating on the bulk bed particles. Deposition on the specimen occurs by transfer of agglomerated material from bulk particles during impact. Subsequent impacts compact the deposit into a continuous protective layer.
- OSTI ID:
- 6463296
- Journal Information:
- Corrosion (Houston); (United States), Journal Name: Corrosion (Houston); (United States) Vol. 49:2; ISSN 0010-9312; ISSN CORRAK
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
014000 -- Coal
Lignite
& Peat-- Combustion
36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL REACTIONS
COAL
COATINGS
COMBUSTION
COMBUSTORS
CORROSION PROTECTION
DEPOSITION
DEPOSITS
ENERGY SOURCES
EROSION
FLUIDIZED-BED COMBUSTION
FLUIDIZED-BED COMBUSTORS
FOSSIL FUELS
FUELS
HEAT EXCHANGERS
IN-VESSEL HEAT EXCHANGERS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PROTECTIVE COATINGS
SIMULATION
STEELS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
THERMOCHEMICAL PROCESSES
TUBES