Electrochemical abatement of gaseous pollutants NO/sub x/ and SO/sub x/ in coal-combustion exhaust gases employing a solid-oxide electrolyte [electronic resource] : Progress report No. 5, October 1--December 31, 1987

Published:: Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 1987.
Physical Description:: Pages: 7 : digital, PDF file
Additional Creators:: United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

Since the last report over two hundred experimental runs have been made in which the relative rates of cathodic reduction of NO compared to O/sub 2/ were obtained in the temperature range of interest for flue gas treatment (FGT) reactors: 400--700/degree/C. Erbia (Er/sub 2/O/sub 3/) stabilized-bismuth oxide (Bi/sub 2/O/sub 3/) (ESB) of composition (Bi/sub 2/O/sub 3/)/sub 0.80/(Er/sub 2/O/sub 3/)/sub 0.20/ was chosen as the moderate temperature solid-electrolyte which has about the same oxygen-ion conductance in the above temperature range as YSZ has at 700--1000/degree/C. The reactivity of NO and O/sub 2/ on ESB at 600/degree/C was found to be comparable to that of YSZ at 850/degree/C, the temperature range for combustion gas cleanup. This important result, for practical FGT-reactor design at moderate temperatures, again supports the hypothesis that electronic defects such as F-centers associated with the oxygen-ionic conductance of the electrolyte provide the electrocatalytic active sites, overshadowing the Arrhenius-temperature effect for the dissociation kinetics of the given oxygen species. As was found with YSZ, NO on ESB is selectively electro-reduced to N/sub 2/ as compared to O/sub 2/ around 500/degree/C; however, above 600/degree/C NO and O/sub 2/ appear to be reduced at about the same rate. This interesting change in selectivity and mechanism is also accompanied with a change in activation enthalpy: 30 kcal/mole below 600/degree/C and 10 kcal/mole above 600/degree/C. 6 refs., 4 figs.

Report Numbers:

E 1.99:doe/pc/90510-t6
doe/pc/90510-t6

Subject(s):

Note:

Published through SciTech Connect.
01/01/1987.
"doe/pc/90510-t6"
"DE89016398"
Mason, D. M.
Stanford Univ., CA (USA). Dept. of Chemical Engineering

Funding Information:

FG22-86PC90510

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