SO/sub 2/NO/sub x/ removal by Ca(OH)/sub 2/

Technical Report · Fri Jan 01 00:00:00 EST 1988

OSTI ID:5157031

Chu, P; Rochelle, G T

Previous workers have shown that simultaneous SO/sub 2/NO/sub x/ removal can be obtained in a dry scrubbing system with Ca(OH)/sub 2/produces more reactive solids and product recycle improve the reactivity of the solids toward SO/sub 2/. To test SO/sub 2/NO/sub x/ removal with fly ash and products recycle, bench-scale experiments with a packed bed reactor were performed at bag filter conditions. The most reactive solid fo NO/sub x/ removal was prepared by slurring Ca(OH)/sub 2/ with fly ash, CaSO/sub 3/, and NaOH. The best conditions for NO/sub x/ removal were high temperatures (tested up to 125/degrees/C) and high concentrations of SO/sub 2/ (tested up to 1500 ppM) and O/sub 2/(tested up to 20%). At the best conditions, NO/sub x/ removed in 1 hour was 3 to 4 moles per 100 moles Ca(OH)/sub 2/, compared to 5 to 10 moles SO/sub 2/ removed per 100 moles Ca(OH)/sub 2/. For the greatest SO/sub 2/ removal, it was necessary to prepare solids by slurring Ca(OH)/sub 2/ with fly ash and NaOH. The best SO/sub 2/ removal was obtained at higher relative humiditieslower temperatures. At these conditions, SO/sub 2/ removal in 1 hour was 60 to 80 moles SO/sub 2/ per 100 moles Ca (OH)/sub 2/, compared to 0.5 to 1 moles NO/sub x/ removed per 100 moles Ca(OH)/sub 2/. NaOH played an important role in SO/sub 2/ and NO/sub x/ removal - as an improvement to fly ash dissolution, as a deliquescent, and as possible catalyst for NO/sub x/ removal. When slurried with fly ash and NaOH, CaSO/sub 3/ substantially improved the solids reactivity toward NO/sub x/, but did not affect SO/sub 2/ removal. No optimum temperature for simultaneous SO/sub 2/NO/sub x/ removal was found. NO/sub x/ removal increased with temperature while SO/sub 2/ removal decreased. 32 refs., 24 figs., 16 tabs.

• Research Organization: Texas Univ., Austin (USA). Dept. of Chemical Engineering
• DOE Contract Number: FG22-85PC81006
• OSTI ID: 5157031
• Report Number(s): DOE/PC/81006-T1; ON: DE88010148
• Resource Relation: Other Information: Thesis
• Country of Publication: United States
• Language: English

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