Method and system for removing nitrogen oxides (NOx) and sulfur dioxide (SO2) from flue gases with the production of nitrogen fertilizer

摘要

The object of the invention is the method and system for removing nitrogen oxides (NOx) and sulphur dioxide (SO2) from boiler exhausts with nitrogen fertiliser production, applicable in particular in coal blocks. The way nitrogen oxides (NOx) and sulphur dioxide (SO2) are removed from the exhaust gas with nitrogen fertiliser is that nitrogen oxide is oxidised in the exhaust gas by ozone and the resulting diazo pentathene in reaction with steam creates nitric acid which is neutralised with potassium hydroxide or sodium nitrate to potassium or sodium nitrate,where nitrogen dioxide is also oxidised and absorbed together with sulphur dioxide and oxygen in the flue-gas stream of a suspension of calcium hydroxide or calcium carbonate from which the sulphur dioxide forms calcium sulphate, then oxidised with oxygen to sulphate at the catalytic action of nitrogen dioxide, with nitrogen dioxide reduced to molecular nitrogen N2. A system for removing nitrogen oxides (NOx) and sulphur dioxide (SO2) from exhaust gas with nitrogen fertiliser production equipped with a boiler,a rotary air heater, an electrofilter, an exhaust cooler, an exhaust fan and a chimney cooler is characterised by the presence of an ozone generator (9) and an ozone delivery system (10),which is directly connected to the oxidising chamber (11),further combined with a spray absorber (12).