| 摘要 |
A method and system for removing SO3 and SO2 from a flue gas produced by the burning of a fossil fuel. Particulates are removed from the flue gas to produce partially cleaned flue gas. A sufficient amount of calcium-based, sodium based or magnesium-based dry sorbent, preferably having a particle size larger than 1.0 - 2.0 microns, is injected into the flue gas to react with and remove substantially all of the SO3 from the partially cleaned flue gas to produce a substantially SO3-free flue gas containing reacted and unreacted dry sorbent. The substantially SO3-free flue gas is conveyed to wet scrubber means for removing SO2 to produce cleaned flue gas. In a first embodiment, sufficient dry sorbent is provided to remove desired amounts of SO3 and SO2. In a second embodiment, a make-up reagent provided to the wet scrubber means wets the dry sorbent, removes both the reacted and unreacted dry sorbent from the substantially SO3-free flue gas, and makes the unreacted dry sorbent available as a reagent for SO2 removal, the make-up reagent and the unreacted dry sorbent reacting with and removing the SO2 from the substantially SO3-free flue gas to produce cleaned flue gas.
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