Electrochemical Desulfurization of Waste Gases in a Batch Reactor
To meet the increasing need for reduction of exhaust emissions from stationary sources, many technologies have been developed to remove SO2 from flue gas. In this study the anodic oxidation of sulfur dioxide in aqueous solutions of sulfuric acid with a unique reactor design and electrode configurati...
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Veröffentlicht in: | Journal of environmental engineering (New York, N.Y.) N.Y.), 2007-01, Vol.133 (1), p.13-19 |
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Sprache: | eng |
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Zusammenfassung: | To meet the increasing need for reduction of exhaust emissions from stationary sources, many technologies have been developed to remove
SO2
from flue gas. In this study the anodic oxidation of sulfur dioxide in aqueous solutions of sulfuric acid with a unique reactor design and electrode configuration has been investigated. An electrochemical absorption column larger than laboratory scale was employed. A titanium rod cathode and platinum expanded mesh anode separated by a cation exchange membrane were used as electrodes in the cylindrical electrochemical reactor. The effects of current densities of 10, 1, and
0.1
Am−2
, initial
SO2
concentrations of 500, 2,500, and
5,000
ppm
, gas flow rates of 0.75, 1.5, and
5
L min−1
, sulfuric acid concentrations of 1, 5, and
10%(w)
, gas composition, and electrolysis time on removal efficiency, current efficiency, energy consumption, and mass transfer coefficient were reported. Removal efficiency of 94% was obtained with a high current efficiency of 94%, energy consumption of
2.22×
10−2
kW
hm−3
, and mass transfer coefficient of
5.9×
10−5
ms−1
without additives or pretreatment. At the current densities of 0.1, 1, and
10
Am−2
, the removal efficiencies were 10, 94, and 98%, respectively. Removal efficiency was observed to decrease as inlet
SO2
concentration, gas flow rate, and electrolyte concentration increased. The presence of
CO2
in the gas mixture led to a decrease in the
SO2
removal efficiency. During electrochemical absorption of
SO2
into the
H2
SO4
solution, the concentration of acid is increased from 5 to 10%. At the end of the studies, electrochemical desulfurization succeeded in meeting the regulation requirement, and the absorbing liquid remained in a reusable form. |
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ISSN: | 0733-9372 1943-7870 |
DOI: | 10.1061/(ASCE)0733-9372(2007)133:1(13) |