The present invention specifically relates to a method and apparatus for removing pollutants of sulfur, nitrogen and metals from a fossil fuel fired power plant flue gas containing the same. In one embodiment, the process comprises introducing an ammoniacal substance into the flue gas in an amount sufficient to react with a substantial portion of the sulfur and nitrogen pollutants therein; cooling the flue gas by passing the gas past the exterior surfaces of a plurality of heat exchanger tubes which contain a cooling fluid therein and which are configured to define a serpentine passage in a downwardly descending manner at an angle of between about 10 to 60 degrees from the horizontal to condense ammonium sulfate or sulfite compounds from the flue gas; and collecting and removing the condensed compounds from the flue gas at several locations below the heat exchanger tubes as the flue gas passes thereby along the passage. In another embodiment, an apparatus for carrying out the process is disclosed.
