TREATMENT OF STACK GAS FROM BOILER PLANT AND DEVICE THEREFOR

摘要

PROBLEM TO BE SOLVED: To efficiently and surely suppress the corrosion of structural equipment caused by SO2 by removing sulfur oxide in a waste gas in a desulfurizing equipment and charging a powdery primary alkaline agent except ammonia and a slurry like secondary alkaline agent except ammonia at an inlet and outlet of an air preheater. SOLUTION: The waste gas discharged from a boiler main body 1 is introduced into the air preheater 3 after Nox is removed in a denitrification equipment 2 and cooled by air for combustion. In such a case, the powdery primary alkaline agent except ammonia is charged into the inlet side of the air preheater 3 from a primary alkaline agent charging device 10 and the slurry like secondary alkaline agent is charged into the outlet side of the air preheater 3 from a secondary alkaline agent charging device 11. A reaction for neutralizing SO2 occurs to prevent the corrosion or the like of the element of the air preheater 3 by charging the primary alkaline agent. And by charging the secondary alkaline agent, SO2 is completely neutralized to eliminate the fear of corrosion.