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Lookup NU author(s): Dr Terence Chin Chin, Professor Chun Yang Yin
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
© 2023 The Author(s)A novel wet scrubber comprising of an oxidation and a reducing section in series was used for the removal of SO2 and NOx from simulated ship emissions. Sodium chlorite (NaClO2) and sodium thiosulfate (Na2S2O3) were used for the oxidizing and reducing sections, respectively. Results showed that although increasing the pH of the chlorite oxidant led to less NO being oxidised, lower rates were achieved for both soluble nitrogen formation (chiefly in the form of nitrates) and reactant consumption per mole of pollutant removed. On the reduction side, it was shown that although the more well-known sulfite (Na2SO3) was about 15% more efficient in removing NO2 compared to thiosulfate, the latter had a very low reactant consumption rate, about 118 and 27 times less compared with sulfite and formaldehyde-stabilised sulfite. The formation of soluble nitrogen was also very low for thiosulfates (less than 0.18 mols formed per mole of NOx removed) or between 1.6 and 1.8 times less when compared with sulfites, as most of the pollutant was reduced to harmless N2. Although thiosulfates formed sulfur precipitates during reaction, this could be circumvented by operating at a high pH. A certain percentage of washwater from the scrubbers can also be discharged, with mixing from the oxidation and reduction sections for the adjustment of oxidation potential, within the allowable nitrate limits.
Author(s): Chin T, Tam I, Yin C-Y
Publication type: Article
Publication status: Published
Journal: Chemical Engineering Journal
Year: 2023
Volume: 464
Print publication date: 15/05/2023
Online publication date: 17/03/2023
Acceptance date: 03/03/2023
Date deposited: 18/04/2023
ISSN (print): 1385-8947
ISSN (electronic): 1873-3212
Publisher: Elsevier B.V.
URL: https://doi.org/10.1016/j.cej.2023.142299
DOI: 10.1016/j.cej.2023.142299
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