PROCESS FOR THE REMOVAL OF IMPURITIES FROM GAS STREAMS

摘要

The present invention relates to a process for removing nitrogen oxides, sulfur dioxides and mercury from gas streams such as furnace or utility boiler flue gas streams, particularly those derived from coal-fired utility boilers. A stream containing relatively low concentration of ozone from an ozone concentrator is feed to a barrier discharge reactor. Nitrogen oxides and mercury in the flue gas are oxidized by oxygen and hydroxyl radicals formed in the reactor. The flue gas is then directed to a reactor duct along with the ozone at a greater concentration wherein the remaining nitrogen oxides and mercury in the gas stream will react with the ozone to form nitric acid, nitric acid precursors, mixtures thereof and mercuric oxide. These impurities can then be removed from the gas stream by use of an aqueous scrubber, a wet electrostatic precipitator, a dry scrubber or a semi-dry scrubber.