Research on products of simultaneous removal of SO2 and NOx from flue gas by ozonation and alkaline absorption

The results of laboratory scale research have been presented on the effects of ozonation of carrier gas containing NO_x and SO₂ on by-products trapped in Dreschel washers with solution of sodium hydroxide. The controlling parameter in this process was the ozonation intensity determined by the molar ratio O₃/NO_x. The measured by-products in a scrubber were SO₃^2- , SO₄^2- , NO₂^- and NO₃^- ions. It has been shown that ozonation of flue gas favours oidation of nitrites to nitrates and sulfites to sulfates in alkaline solution. Some of these results were confirmed in a pilot scale studies. Pilot plant was located in Wroclaw CHP (Combined Heat and Power), which provided flue gas for testing at a rate of 200 m³/h from the OP-430 boiler. Exhaust gases were ozonized and captured simultaneously with SO₂. Sodium hydroxide was used in a pilot scale as an absorbent.