Principle: Under the action of catalyst, inject ammonia into 280-420℃ fumes , so as to deoxidize NOx into N2 and H20.

The principle of double alkali method fume desulfurization technology is that adopt sodium hydroxide solution as a starting desulfurize agent, put formulated sodium hydroxide solution directly into the desulfurization tower so as to wash and desulfurize SO2 of fumes, and then these desulfurization by-product deoxidized sodium hydroxide through desulfurization regeneration tank and then back into the desulfurization tower for recycling.

Limestone or lime is used as a desulfurization absorbent, limestone is broken and finely ground into powder,then mixed with water to form an absorbent slurry, when lime is used as an absorbent, lime powder is digested and made into an absorbent slurry. In the absorption tower, the absorbent slurry is mixed with the fume, and the sulfur dioxide in the fume reacts with the calcium carbonate in the slurry and the air oxide in the drum so as to be removed, and final reaction product is gypsum.