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Scale suppression in lime/limestone FGD systems

Conference · · Am. Chem. Soc., Div. Pet. Chem., Prepr.; (United States)
OSTI ID:6790236

Scale suppression in lime/limestone FGD systems may be to prevent the oxidation of sulfite to sulfate. Thus, the effect of NO/sub x/ on sulfite oxidation was studied in semibatch laboratory-scale experiments with a 5Vertical Bar3< slurry of hydrated lime containing some fly ash and calcium chloride as the scrubbing liquid and a simulated flue gas containing 76.9Vertical Bar3< by vol nitrogen, 11.1Vertical Bar3< carbon dioxide, 4.7Vertical Bar3< oxygen, 7.0Vertical Bar3< water, 0.25Vertical Bar3< sulfur dioxide, and 0-0.08Vertical Bar3< each of NO and NO/sub x/; the gas flow rate and stirrer speed were held constant at 5 l./min and 1000 rpm, respectively. The NO/sub 2/ acted as a promoter (either catalytically or as a direct oxidant), and NO as an inhibitor, of sulfite oxidation, but the inhibiting effect was insufficient to offset the promoter at NO:NO/sub 2/ molar ratios below 12:1. Oxidation was minimized at 20:1 ratio. The NO/sub x/ composition of industrial boiler flue gases, which typically contain 800 ppm NO/sub x/ at a 9:1 mole ratio can be adjusted by prescrubbing with urea or sulfuric acid solutions to remove NO/sub 2/.

Research Organization:
Battelle Mem. Inst., Columbus Lab.
OSTI ID:
6790236
Report Number(s):
CONF-790415-
Journal Information:
Am. Chem. Soc., Div. Pet. Chem., Prepr.; (United States), Journal Name: Am. Chem. Soc., Div. Pet. Chem., Prepr.; (United States) Vol. 24:2; ISSN ACPCA
Country of Publication:
United States
Language:
English