SCR denitration, liquid ammonia vaporization
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Experts, since ammonia water is used as a reducing agent in SCR denitration, what method should be employed for vaporizing liquid ammonia?
Liquid ammonia is definitely vaporized by heating, usually using a water bath.
My question now is this: in SCR denitration, 25% ammonia solution comes into direct contact with flue gas; the temperature of the flue gas is used to vaporize the ammonia solution, which then enters the reactor. The flue gas temperature is around 150°. What methods can be used to ensure that the ammonia solution vaporizes rapidly within the flue duct?
If it is 25% ammonia solution, it can only be atomized using a two-fluid spray gun. Compressed air is usually used for atomization. It is first atomized into small droplets and then evaporated into a gaseous state.
The flue gas temperature is around 150–200°; with atomization using a spray gun, how long does it take for ammonia water to vaporize?
Whether it is liquid ammonia or ammonia water – let’s not discuss that for now. Starting with liquid ammonia, it is transported in tank trucks and poured into storage tanks. Liquid ammonia is atomized and absorbed using circulating water to produce ammonia water with a concentration of 25–28%. Atomization of the ammonia water can be achieved through nozzles built into venturi tubes; due to the high temperature, the ammonia water is atomized instantly.
Still using SCR at a flue gas temperature of 200°C? If you are working on lab-scale tests for low-temperature catalysts, you can give it a try; but if it’s industrial SCR, it’s better not to attempt it. . .
At 200°C, it’s better not to spray ammonia water directly; use water bath heating instead
Compressed air + spray; 200 degrees seems to be insufficient as a temperature for catalyst activation
First, what you need to prepare is ammonia water; it’s not the vaporization of liquid ammonia, but rather the vaporization of ammonia water. Super ammonia absorbers can be used to produce ammonia water from liquid ammonia.
With a flue gas temperature of 200°C, SCR or SNCR is not actually suitable; the ozone method or low-temperature plasma method are better options.