Modeling the behavior of selenium in Pulverized-Coal Combustion systems

Journal Article · Mon Nov 15 04:00:00 EST 2010 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2010.05.004· OSTI ID:21379816

Senior, Constance; Otten, Brydger Van; Wendt, Jost O.L.; Sarofim, Adel ^[1]

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1. Reaction Engineering International, 77 W. 200 South, Salt Lake City, UT 84101 (United States)

The behavior of Se during coal combustion is different from other trace metals because of the high degree of vaporization and high vapor pressures of the oxide (SeO{sub 2}) in coal flue gas. In a coal-fired boiler, these gaseous oxides are absorbed on the fly ash surface in the convective section by a chemical reaction. The composition of the fly ash (and of the parent coal) as well as the time-temperature history in the boiler therefore influences the formation of selenium compounds on the surface of the fly ash. A model was created for interactions between selenium and fly ash post-combustion. The reaction mechanism assumed that iron reacts with selenium at temperatures above 1200 C and that calcium reacts with selenium at temperatures less than 800 C. The model also included competing reactions of SO{sub 2} with calcium and iron in the ash. Predicted selenium distributions in fly ash (concentration versus particle size) were compared against measurements from pilot-scale experiments for combustion of six coals, four bituminous and two low-rank coals. The model predicted the selenium distribution in the fly ash from the pilot-scale experiments reasonably well for six coals of different compositions. (author)

• OSTI ID: 21379816
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 11 Vol. 157; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
BITUMINOUS COAL
BOILERS
BROWN COAL
CALCIUM
CHEMICAL COMPOSITION
COMBUSTION
COMBUSTION KINETICS
DISTRIBUTION
FLUE GAS
FLY ASH
IRON
PARTICLE SIZE
PULVERIZED FUELS
SELENIUM
SELENIUM OXIDES
SIMULATION
SULFUR DIOXIDE
SURFACES
TEMPERATURE RANGE 1000-4000 K
VAPOR PRESSURE