A multiple-field precipitator, flue-gas treating device, in accordance with the
principles of the invention, includes a first section having a dual-function, sensible-cooling
heat exchanger/electrostatic precipitator, a second section having a wet electrostatic
precipitator, and a middle section fluidly connecting the first and second sections.
In the first section, the exchanger/precipitator sensibly cools the flue gas and
collects most of the dust from the flue gas. In the middle section, the dust-reduced
flue gas is combined with an alkaline material, thereby forming reaction products.
These reaction products and several other pollutants are captured by the wet electrostatic
precipitator, in the form of a pollutant-laden liquid. The pollutant-laden liquid
is directed to a series of heat exchangers and settling tanks, where various pollutants
such as SOx, metals, NOx, and chlorides are removed in different
stages. In addition, ammonia is liberated from the pollutant-laden liquid, and
circulated back to the middle section, where it is combined with additional dust-reduced
flue gas to form additional reaction products for subsequent capture in the wet
electrostatic precipitator.