Tampa Electric Company

Aecom Technical Services, Inc.

James David Colley

Sterling Michael Gray

A flue gas desulfurization unit is converted from operating with lime or magnesium enhanced lime under inhibited oxidation into a unit that operates using limestone under inhibited oxidation conditions. A ball mill grinding unit may be installed to crush the limestone thereby producing a suspended slurry of fine limestone particles which is pumped to the reaction vessel. When installed, the ball mill may be installed in the process immediately downstream of the existing slaking equipment. The suspended solution may be maintained at a pH in the range of 3.0 to 6.5, optimally at approximately 5.0 to increase the dissolution rate of the limestone reagent produced by the ball mill. The post-conversion process may also require the addition of organic acids and oxidation inhibitors to achieve better SOremoval from the flue gas.

Method for converting lime-based wet flue gas desulfurization systems to limestone-based systems

In the desulfurization of flue gas utilizing limestone as absorbent in a double loop system, in which the flue gas is introduced into a quenching zone for contact with a first slurry of the limestone, and thereafter passes to an absorbing zone for further contact with a second limestone slurry, the two slurries being supplied from a mixing zone into which water and limestone are charged, and in which air is introduced into the quenching zone to convert the calcium sulfite present in it to gypsum, air is also supplied to the mixing zone to convert calcium sulfite in it to gypsum, and limestone is directly added to the quenching zone.

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Austin, TX, United States of America

James David Colley