Urgently need an answer: In SCR denitration, when ammonia water is used as a reducing agent, why does tube blockage occur so severely?
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Experts, in SCR denitration, ammonia water is used as a reducing agent, and high-temperature air is used to heat the dilute ammonia water solution to generate ammonia gas (ammonia and air mixer). How to dilute the pipeline between the fan and the mixer? The ammonia spraying grid is severely clogged What’s the reason? I’m asking everyone for help in answering this.
There is too much dust in the high-temperature air stream used as the dilution air, which causes blockages in the ammonia injection grids. When high-temperature air is used as dilution air, it is necessary to take adequate measures to keep its dust content within controllable levels; for example, a high-temperature multi-tube dust collector can be used to keep the dust level at 30 mg/m3. Additionally, this is also related to your operating procedures – for instance, the dilution fan should be turned on as well when the exhaust fan is running. If the exhaust fan has been running for a long time while the dilution fan remains off, blockages are likely to occur. Generally speaking, blockages in SCR devices are mainly caused by ammonium hydrosulfide, dust, or incomplete decomposition of urea when it is used as a reducing agent; by paying close attention to the details, it’s not difficult to resolve these issues, as there aren’t many possible sources of blockage. .
Is it high-temperature air or high-temperature flue gas that is used?
It’s mainly due to sulfur dioxide and nitrogen dioxide. I work in the field of desulfurization and denitration as well; we don’t use this technology because its removal efficiency is too low and the annual operating costs are high. It’s a technical issue that cannot be resolved unless we switch to another process
SCR does not remove sulfur dioxide; it only decomposes nitrogen oxides at high temperatures, with an efficiency of around 70-80%. The nitrogen oxides and sulfur dioxide that cannot be decomposed react with ammonia to form ammonium salts, which then crystallize and cause blockages at low temperatures. If you can’t solve this problem, then it’s better not to try. Find a design firm and have them modify their process
Hello, I’ve encountered the same issue. How did you solve it? Thank you
I guess it’s high-temperature smoke! That’s why there is a high level of dust inside.