| 摘要 |
PURPOSE:To efficiently remove nitrogen oxides without deteriorating a catalyst even if it is poisoned at the time of reducing the nitrogen oxides in a gas contg. mercury vapor with a reducing agent in the presence of the catalyst by mixing hydrogen chloride into the gas. CONSTITUTION:Hydrogen chloride is mixed into a waste gas, when the nitrogen oxides in the gas contg. mercury vapor are reduced by a reducing agent in the presence of a catalyst. The gas temperature is regulated to >=150 deg.C being the temperature easy to gasify the mercury chloride. The hydrogen chloride is mixed continuously or at regular time intervals. The amt. of hydrogen chloride to be mixed is controlled to the stoichiometric value (>=2 molar ratio of HCl/Hg) under a condition in which the mercury chloride is not decomposed. Since hydrogen chloride is mixed into the waste gas in this way, the mercury oxide deposited on the catalyst reacts with the hydrogen chloride to form mercury chloride vapor, and the mercury is desorbed from the catalyst. |
