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Investigation of the mechanism of fly-ash formation in coal-fired utility boilers. Annual and Quarterly report, February 1, 1978--January 31, 1979 and November 1, 1978--January 31, 1979

Technical Report ·
DOI:https://doi.org/10.2172/6311571· OSTI ID:6311571

Laboratory flame measurements, equilibrium predictions, and a char-ash vaporization mechanism were employed to generate primitive predictions for the size, quantity and composition of condensation ash in cyclone and pulverized-fuel fired boilers. These were compared with characteristics of the submicron fraction separated from plant samples. Agreement was good in terms of particle size, morphology, and concentration. The predicted depletion of aluminum and enrichment of silicon were also observed, but the measured depletion of iron was contrary to predictions. Hopper ash from the Monroe Station, a PF unit burning coal similar to the Merrimack Station, was examined briefly. The submicron fraction was negligible compared to that in the Merrimack unit. The difference was attributed to lower combustion temperatures employed in PF firing. Predictions for the two boilers confirm these findings. The growth model was further refined with completion of a computer code which predicts primary-particle and aggregate growth. It encompasses a broad range of conditions in both Brownian regimes and the transition ranges.

Research Organization:
New Hampshire Univ., Durham (USA). Dept. of Chemical Engineering
OSTI ID:
6311571
Report Number(s):
FE-2205-15
Country of Publication:
United States
Language:
English