Treatment technologies for nitrogen dioxide in industrial exhaust gases
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Question: What are some effective treatment technologies for nitrogen dioxide in industrial exhaust gases? In particular, what new technologies are currently being used to treat nitrogen dioxide in exhaust gases from nitric acid production processes?
1. Ammonia reduction method. This method is technically mature and offers good treatment results, but it has a high ammonia consumption. 2. Alkali absorption method. This method is simple to operate, but its treatment effect is poor, and the exhaust emissions do not meet the standards. 3. Non-selective reduction method. We have used it in our nitric acid plant before, but due to unstable venting from the raw material tank, it was extremely difficult to operate.
Thank you, second floor. What is the reaction equation for the ammonia reduction method? Is it NH3 + NO2 → N2 + HO2? I’ve also heard that some manufacturers feed nitric acid exhaust gases into waste heat boilers in order to meet the emission standards. What is the basis for doing this? Is it done by converting NO2 + C into N2 + CO2 under the high-temperature conditions of the waste treatment furnace? I would appreciate your guidance, dear friend. :handshake
Reply to 3# Hongchen: The ammonia reduction method involves, under the action of a catalyst, adding ammonia (NH3) to enable NOx to react with NH3 to produce N2 and H2O, thereby avoiding secondary pollution. The basic chemical reaction equations are as follows: 4NO + 4NH3 + O2 → 4N2 + 6H2O; 6NO + 4NH3 → 5N2 + 6H2O; 6NO2 + 8NH3 → 7N2 + 12H2O; 2NO2 + 4NH3 + O2 → 3N2 + 6H2O. The nitric acid exhaust gases are sent to the waste heat boiler so that the emission standards can be met. ”The use of this method in industrial installations has not been heard of yet.