Application of Coal Ash in Fluidized Thermal Beds
Publication: Journal of Materials in Civil Engineering
Volume 14, Issue 5
Abstract
Thermal properties of soils are of great importance in view of the subsurface transmission of either heated fluids or high power currents. Fine-grained soils, in particular clays, pose a serious problem for conduction of heat due to very high thermal resistivity. As such, it becomes mandatory to devise a mechanism by which thermal resistivity of fine-grained soils may be reduced. An engineered backfill, with suitable thermal properties, is adopted frequently to reduce thermal resistivity of these soils. The potential of coal ash (i.e., in the form of either fly ash or lagoon ash) as a suitable backfill material, when mixed with cement, sand, and aggregates, has been explored by several researchers and is well established. However, with increasing amounts of lagoon ash being disposed of at thermal power plants, it is important to study its effectiveness as a fluidizing agent and its use in designing a proper fluidized thermal bed (FTB). Based on laboratory tests on different soils, generalized equations for estimating soil thermal resistivity have been developed in the recent past. These equations have been used for obtaining the optimum quantity of the lagoon ash for designing a fluidized thermal bed. Effect of moisture content and compaction density on thermal resistivity of different FTB compositions has also been studied.
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References
ASTM. (1994). “Specification for coal fly ash and raw or calcined natural pozzolan for use as a mineral admixture in portland cement concrete.” C 618-94, West Conshohocken, Pa., 296–298.
Del Mar, W. A., Burrell, R. W., and Bauer, C. A. (1960). “Soil types: identification and physical properties. II: Soil thermal characteristics in relation to underground power cables.” AIEE Committee Rep., American Institute of Electrical Engineers, New York, 795–803.
Devid, K. (2000). “Detection and estimation of soil thermal resistivity.” MS thesis, Indian Institute of Technology, Bombay, India.
Gupta, G., and Torres, N.(1998). “Use of fly ash in reducing toxicity and heavy metals in waste water Effluent.” J. Haz. Mat., 57, 243–248.
Hooper, F. C., and Lepper, F. R.(1950). “Transient heat flow apparatus for the determination of thermal conductivities.” Trans. Am. Soc. Heating Ventilating Eng., 56, 309–324.
Indraratna, B., and Nutalaya, P.(1991). “Engineering behavior of a low carbon, pozzolanic fly ash and its potential as a construction fill.” Can. Geotech. J., 28, 542–545.
Janardhanam, R., Burns, F., and Peindl, R. D.(1992). “Mix design for flowable fly-ash backfill material.” J. Mater. Civ. Eng., 4(3), 252–263.
Joseph, P., Martin, A., and Francis, J.(1990). “Properties and use of fly ashes for embankment.” J. Energy Eng., 116(2), 71–86.
Joshi, R. C., Duncan, D. M., and McMaster, H. M.(1975). “New and conventional engineering uses of fly ash.” J. Transp. Eng., 101(4), 791–806.
Joshi, R. C., Hettiarchi, J. P. A., and Achari, G.(1994). “Properties of modified Alberta fly ash in relation to utilization in waste management applications.” Can. J. Civ. Eng., 21, 419–426.
Leonards, G. A., and Bailey, B.(1982). “Pulverized coal ash as structural fill.” J. Geotech. Eng. Div., 108, 517–531.
Mehta, P. K.(1985). “Influence of fly ash characteristics on the strength of portland fly ash mixtures.” Cem. Concr. Res., 15, 669–674.
Mishra, L. C., and Shukla, K. N.(1986). “Elemental composition of corn and soyabin growth on fly ash amended soil.” Environ. Pollut., 12, 313–321.
Radhakrishna, H. S., Chu, F. Y., and Boggs, S. A.(1980). “Thermal instability and its prediction in cable backfill soils.” IEEE Trans. Power Appar. Syst., 99(3), 856–867.
Rao, M. V. B. B. G., and Singh, D. N.(1999). “A generalized relationship to estimate thermal resistivity of soils.” Can. Geotech. J., 36(4), 767–773.
Ravina, D., and Mehta, P. K.(1998). “Compressive strength of low cement/high fly ash concrete.” Cem. Concr. Res., 4, 571–583.
Sanger, F. J.(1968). “Ground freezing in construction.” J. Soil Mech. Found. Eng., 94(SM1), 131–158.
Sherwood, P. T., and Ryley, M. D. (1996). The use of stabilised pulverised fuel ash in road construction, Road Research Laboratory, Ministry of Transport, London, 1–44.
Singh, D. N., and Devid, K.(2000). “Generalized relationships for estimating soil thermal resistivity.” Exp. Therm. Fluid Sci., 22, 133–143.
Skarzynska, K. M., Rainbow, A. K. M., and Zawisza, E. (1989). “Characterization of ash in storage ponds.” Proc., 12th. Int. Conf. of Soil Mechanics and Foundation Engineering, 1915–1918.
Slegel, D. L., and Davis, L. R.(1977). “Transient heat and mass transfer in soils in the vicinity of heated porous pipes.” J. Heat Transfer, 99, 541–621.
Tomar, V. S. (1999). “Soil thermal resistivity modeling.” BS thesis, Indian Institute of Technology, Bombay, India.
Toth, P. S., Chan, H. T., and Cragg, C. B.(1987). “Coal ash as structural fill, with special reference to Ontario experience.” Can. Geotech. J., 25, 694–704.
Wang, S., and Viraraghavan, T.(1997). “Wastewater sludge conditioning by fly ash.” Waste Manage., 17(7), 443–450.
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Copyright © 2002 American Society of Civil Engineers.
History
Received: Jun 22, 2000
Accepted: Aug 28, 2001
Published online: Sep 13, 2002
Published in print: Oct 2002
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