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An Investigation of Fluidized Bed Combustion By-Products from Four Iowa Power Plants

Published online by Cambridge University Press:  15 February 2011

Carol L. Kilgour
Carol L. Kilgour*
Affiliation:
Department of Civil and Construction Engineering, Iowa State University, Ames, IA 50011.
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Abstract

Fluidized bed combustion (FBC) residues from four Iowa power plants were characterized to provide background with respect to chemical, physical, mineralogical and microstructural parameters that might affect their utilization potential. Methodologies used include: bulk chemical analysis; grain size analysis; specific gravity determination; mineralogical analysis by x-ray diffraction; scanning electron microscopy; and thermal analysis.

Chemical analysis of the major components showed the separation of the constituents during combustion. The bottom ash is derived from the calcined and partly sulfated limestone, thus the concentration of calcium and sulfur compounds is greater. The fly ash however is derived mostly from the coal and therefore exhibits higher concentrations of coal ash components such as silica (SiO2), alumina (Al2O3), and ferric oxide (Fe2O3). The alkalis appear to be more concentrated in the fly ash.

The measured particle size distributions of the bulk samples varied greatly, from extremely coarse (mean particle size ˜2000 μm) to fine (mean particle size ˜25 μm). The size distributions also varied in breadth. Specific gravities values recorded ranged from about 2.65 to about 3.05.

X-ray diffraction analyses showed that most of the FBC by-products contain, as easily detectable crystalline components, only quartz, anhydrite and lime, and as is to be expected due to the low combustion temperatures, do not show broad peaks characteristic of glass in conventional fly ashes. Scanning electron microscopy revealed the FBC by-products to be extremely intricate mixtures of particles of complex and variable composition and internal structure.

FBC by-products are shown to be extremely complex mixtures of particles of variable composition and internal structure. However, despite their local variation, useful results can be obtained by overall chemical and physico-chemical analyses of their composition. The exploitable properties of FBC residue include the somewhat cementitious nature and the granularity. However, their heterogeneous nature, lack of pozzolanic properties, and elevated sulfate content may limit their uses, especially in construction.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 245: Symposium K – Advanced Cementitious Systems: Mechanisms and Properties , 1991 , 81
Copyright
Copyright © Materials Research Society 1992

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References

REFERENCES

[1] Harness, J.L. Chung, Y.C., and Mays, D.A. (1987), “Shawnee AFBC Demonstration Project Ash Utilization Program” Proc. 9th Int. Conf. Fluidized Bed Combustion Vol. II, (1987), pp 927–934.Google Scholar
[2] Harness, Jerry L. (1989), “Overview of the DOE Office of Fossil Energy Waste Management Program.” Proc 15th Bienn. Low Rank Fuels Symposium, May 1989 pp 545–553.Google Scholar
[3] Schlorholtz, S, and Boyboy, M., in Advances in X-Ray Analysis, Vol 27 (Plenum Publishing Co., New York, 1984) pp. 497–504.10.1007/978-1-4613-2775-2_59CrossRefGoogle Scholar
[4] Lovell, J. and Diamond, S., in Fly Ash and Coal Conversion By-Products: Characterization, Utilization and Disposal II, edited by McCarthy, G.J., Glasser, F.P. ad Roy, D.M., Mat. Res. Soc. Symp. Proc. Vol 65 pp 131–136.Google Scholar
[5] GAI Consultants, Inc. Coal Ash Disposal Manual, FP-1257, RP 1404–1. Final Report, December 1979. Prepared tor the Electric Power Research Institute (EPRI).Google Scholar
[6] Kilgour, C.L., and McGowan, K.I., “Characterization and Utilization of By-Products from Four Iowa Fluidized Bed Combustion Units.” Final Report, Electric Power Research Center, Iowa State University, Ames IA 50011, October 1991.Google Scholar
[7] Miller, Bruce G., Romans, David E., and Scaroni, Alan W., “Characterization of Limestones for FBC Systems,” The National Stone Association SO2-Emission Control Conference, Pittsburgh, PA, September 1990.Google Scholar
[8] Collins, R.J., “Utilization of Fluidized Bed Combustion Wastes.” Journal of Testing and Evaluation JTEVA, Vol.8, No. 5, Sept.1980, pp 259–264.Google Scholar
[9] Minnick, J.L., ”Development of Potential Uses for Residues from Fluidized Bed Combustion Boilers” U.S. Department of Energy, and Appalachian Regional Commission Contract No Report No. DOE/ET/10415–1163, Morgantown, West Virginia. December 1982.10.2172/12182891CrossRefGoogle Scholar
[10] Berry, E.E., Anthony, E.J., and Kalmanovitch, D.P., (1987), “The Uses and Morphology of Atmospheric Fluidized Bed Combustion Wastes from Canada's First Industrial AFBC Boilers.” Transactions of the ASME Vol.109, Sept. 1987, pp 148–154.Google Scholar