How to deal with nitrogen dioxide produced by the decomposition of nitric acid
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Since concentrated nitric acid (68%) is used as an oxidizing agent, and nitric acid decomposes to produce large amounts of nitrogen dioxide gas in a heated environment, what is the appropriate way to deal with this? The current method involves cooling with coils first, followed by absorption with alkali.
If the flow rate remains low, the gas can be passed through concentrated sulfuric acid for absorption.
Reply 2# will-*u*an: The quantity is large, at least 200 L of concentrated nitric acid, with a reaction time of 14-15 hours
Absorbing nitrogen dioxide with alkalis is not very effective! It is recommended to use an urea aqueous solution for absorption!
Reply to 1# angelyds: If liquid is used for absorption, the removal rate is very low. Moreover, if that liquid cannot be reused in production, it still needs to be treated, and dealing with it is also quite difficult. For such large quantities, the ammonia reduction method can be used: ammonia gas is introduced into the exhaust gases, and at a certain temperature, through the catalytic reduction action of a catalyst, nitrogen dioxide is converted into nitrogen and water. As a result, the emissions meet the required standards after treatment. In the special steel surface treatment lines of Baosteel Plant 1 and Shanggang Plant 5, ammonia reduction is used for exhaust gas treatment. The effect is very noticeable. If you have the parameters, I can help you create a plan. My phone number is 130 5733 8636, and my QQ ID is 3455 60301
Here, we use a negative pressure pump to draw nitrogen dioxide gas into a tank containing water; the gas is then absorbed by the water, turning it into acidic water. This acidic water can be used elsewhere for neutralization, or ammonia can be added directly to neutralize it (neutralization with ammonia is cheaper than using alkalis)
Reply to 4# scene000: Treating nitrogen dioxide gas with alkalis is not effective; so what is a good alternative?
There’s something to learn in this area; it’s quite interesting.
How to consider the recycling of ammonia after it has been absorbed? Ammonia emissions affect COD; seeking advice
Find a substance to absorb it, one that cannot also absorb *ao acid.
High-temperature reduction is used to convert NOx in the exhaust gases into N2; this process does not cause secondary pollution