Effects of alternate fuels. Report No. 6. Analysis of low-alumina castable refractory degraded by residual oil combustion products
This is the sixth of a series of reports on analyses of several types of refractories used in industrial furnaces with fuels considered alternate to natural gas. Analyses were performed on a low-alumina castable used for only two months in the roof of a residual-oil-fired boiler. The maximum hot-face temperature during operation was about 1530/sup 0/K. The original microstructure of the castable, which consisted of mullite aggregate bonded with iron-containing gehlenite (2 CaO . Al/sub 2/O/sub 3/ . SiO/sub 2/), quartz and cristobalite, was totally altered during service in regions close to the hot face. At room temperature the altered microstructure consisted of corundum and gehlenite in a new oxide glass phase containing the elements Na, K, Ca, Fe, Ti, Al, Ni, and Si. The reactions of the fuel oil impurities Na, Fe, and Ni with mullite, quartz, and cristobalite in the original castable refractory caused the rapid degradation at the hot face during service in the boiler. Increasing the Al/sub 2/O/sub 3/ content of the castable by replacing mullite aggregate with alumina aggregate and using gehlenite with less iron impurity as the bonding material should improve the performance of this castable refractory or retard reactions of the castable with fuel oil combustion products including Na, Fe, and Ni.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6691587
- Report Number(s):
- ORNL/TM-6334
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
20 FOSSIL-FUELED POWER PLANTS
BOILERS
THERMAL INSULATION
FURNACES
REFRACTORIES
DECOMPOSITION
ALUMINIUM OXIDES
CHEMICAL REACTIONS
COMBUSTION PRODUCTS
CORROSIVE EFFECTS
INDUSTRIAL PLANTS
IRON
NICKEL
RESIDUAL FUELS
SODIUM
ALKALI METALS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
ELEMENTS
FUEL OILS
FUELS
METALS
OILS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PETROLEUM PRODUCTS
TRANSITION ELEMENTS
421000* - Engineering- Combustion Systems
200101 - Fossil-Fueled Power Plants- Cooling & Heat Transfer Equipment & Systems