Selenium emission control at high temperatures with mineral sorbents. Final report, September 1, 1994--February 29, 1996
The focus of this project is on toxic metal removal by sorbent injection in the upper furnace and economizer sections of a coal- fired boiler. Selenium was chosen as the candidate heavy metal to be studied because of its high volatility and associated difficulties in removal. A thorough mechanistic investigation of the SeO{sub 2}-Ca(OH){sub 2} interaction at both medium and high temperatures has been conducted in this project. Experiments were performed in the two temperature ranges in the presence and absence of O{sub 2}; desorption studies were conducted to characterize the nature of interaction; and XRD/XPS and Ion Chromatography studies were performed for species identification. It was inferred from these findings that the selenium capture was significantly more in the medium temperature range (450-650{degrees}C) than in high temperature range (800-1000{degrees}C) and the captured selenium species in the medium temperature range is in the form of calcium selenite (CaSeO{sub 3}) and a reaction scheme was proposed for the CaO/SeO{sub 2} interaction: CaO (s) + SeO{sub 2} (g) = CaSeO{sub 3} (s). This reaction process does not require the participation of oxygen, as was confirmed by various analytical techniques and supported by the experimental evidence. Results of the high-temperature studies indicate much reduced capture at these temperatures with negligible selenium sorption above 900{degrees}C. This behavior was attributed to the decomposition of calcium selenite at higher temperatures.
- Research Organization:
- The Ohio State Univ., Columbus, OH (United States)
- Sponsoring Organization:
- Ohio State Government, Columbus, OH (United States)
- OSTI ID:
- 419438
- Report Number(s):
- OCDO-97001484; ON: TI97001484
- Resource Relation:
- Other Information: PBD: Mar 1996
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
20 FOSSIL-FUELED POWER PLANTS
54 ENVIRONMENTAL SCIENCES
FLUE GAS
DEMETALLIZATION
SELENIUM
SORPTION
CALCIUM HYDROXIDES
SORPTIVE PROPERTIES
REMOVAL
PROGRESS REPORT
EXPERIMENTAL DATA
X-RAY DIFFRACTION
CHROMATOGRAPHY
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE DEPENDENCE
CHEMICAL REACTION KINETICS
SELENITES
CALCIUM COMPOUNDS