| 摘要 |
<p>PURPOSE:To prevent the adhesion of dust to heat exchangers and also the corrosion of elements by the procedure in which silicon dioxide-containing iron oxide, etc., is injected into the upstream side of heat exchangers to cause the reaction of it with acid ammonium sulfate to take place in a dry type denitrification method in which ammonia is injected into exhaust gas. CONSTITUTION:In a dry denitrification method in which NOx present in combustion exhaust gas is treated by ammonia as a reducing agent with or without catalyst, an additive, e.g., SiO2-containing iron oxide or an alkaline earth metal salt, e.g., magnesium oxide, etc., is introduced into the upstream side of heat exhanger to cause the reaction of NOx present with acid ammonium sulfate (NH4HSO4) formed from the reaction of unreacted NH3 after denitrification, SO3 present in exhasut gas, and water to take place, and then the reaction product thus formed and accumulated in the reaction system is removed by a soot blow operation. The preferred amount of the additive is 1 to 10 times equivant of SO3 present in exhasut gas, preferably 2 to 5 times equivalent.</p> |
