Thiosulfate as an Oxidation Inhibitor in Flue Gas Desulfurization Processes: A Review of R&D Results |
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| Authors: | Gary T Rochelle David R Owens John C S Chang Theodore G Bma |
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| Institution: | 1. The University of Texas at Austin , Austin , Texas , USA;2. Acurex Corporation , Research Triangle Park , North Carolina , USA;3. U.S Environmental Protection Agency , Air and Energy Engineering Research Laboratory , Research Triangle Park , North Carolina , USA |
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| Abstract: | Sodium thiosulfate (Na2S2O3) has been tested in a pilot plant as an oxidation inhibitor in flue gas desulfurization by lime and limestone slurry scrubbing with and without MgO and adiplc acid additives. The effectiveness of thiosulfate is proportional to the inhibitor product, defined as the product of thiosulfate concentration (M), calcium concentration (M), and the moles of SO2 absorbed per hour per liter of hold tank volume. Gypsum saturation was less than 100 percent and scaling was eliminated when the inhibitor product exceeded 0.3 × 10?6(gmol/L)3/h. Thiosulfate was relatively more effective in systems with chlorides and less effective in systems promoted by MgO. An inhibitor product greater than 10?6(gmol/L)3/h significantly enhanced dewatering of solids from limestone scrubbing. SO2 removal and/or limestone utilization were increased in systems that started with less than 10 mM dissolved calcium. |
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