Desulfurization of Flue Gases in A Fluidized Bed of Modified Limestone |
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Authors: | G. Van Houte B. Delmon J.C. Maon Ph. Dumont |
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Affiliation: | 1. Université Catholique de Louvain , Louvain-la-Neuve , Belgium;2. Carrières et Fours à Chaux Dumont-Wautier , Hermalle-sous-Huy , Belgium |
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Abstract: | This publication concerns the dry removal of SO2 from gases using limestone absorbents. It reports bench-scale experiments made with commercial samples of powdered limestone (CaCO3) activated by addition of a cheap substance, namely CaCl2. The absorption was carried out in a fluidized bed traversed by the flue gases, between 600° and 900° C. The degree and rate of transformation of CaCO3 to CaSO4 in the presence of SO2 and air have been compared for unmodified and modified absorbents. Initial rates of reaction, and the variation of the rate of absorption with time have been measured. The influence of the SO2 content of the gas has been assessed. At 700° C, the maximum degree of transformation of activated limestone to sulfate exceeds 90%, whereas untreated CaCO3 transforms only to 16–20%. At the same temperature, more than 90% of SO2 contained In a gas carrying 0.35% SO2 is removed. Because of the much smaller quantity of solid absorbent required, dry absorption processes based on the modified absorbents might get renewed interest. The modified absorbents might also be used for in situ absorption in fluidized bed combustion, in which the temperatures are in the range studied in the present paper. |
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