PURPOSE: To maintain the denitration capacity of an absorbing soln. for a long time in treatment of waste gases of high contents of SOx and O2 by maintaining the temp. of an iron-EDTA soln. lower than that in the prior art, and controlling pH at the point of the time when the denitration capacity drops sharply.
CONSTITUTION: In a wet type denitration method for absorbing away the NOx in various waste gases contg. SOx by the use of an FeII-EDTA soln., the NOx in the waste gases is absorbed in the FeII-EDTA soln. under the temp. thereof maintained at ≤20°C at all times, whereby the duration time of the absorbing capacity of the FeII-EDTA soln. is made longer. At the point of the time when the denitration capacity of the NOx absorbing soln. decreases sharply by the effect of the SOx and O2 in the waste gases, an alkaline material is added to control the pH to 6.5W7.5 which is an optimum range for absorption of NOx, whereby the denitration capacity is restored.
TSUNODA TAKEO
HATA TOSHIHIKO
