Flue gas-treating method and apparatus for treating acidic tail gas by using ammonia process

A flue gas-treating method for treating acid tail gas by an ammonia absorption process, the process comprising:

• 1) flowing raw tail gas into an inlet duct of an absorber, and adding air into the raw tail gas via an air blower, which is connected to the inlet duct, to make the concentration of sulfur dioxide in said raw tail gas reach a concentration of <30,000 mg/Nm3, before the tail gas flows into the absorber;
• 2) cooling and washing the tail gas by spraying the tail gas in a cooling washing spray layer with water and/or ammonium sulfate solution produced in an oxidation section, wherein said cooling washing spray layer is in the inlet duct of the absorber or inside the absorber, and wherein the concentration of the ammonium sulfate solution increases when spraying the tail gas with ammonium sulfate solution;
• 3) desulfurizing the tail gas in an absorption section of the absorber by spraying the tail gas via absorption solution distributors with absorption solution containing ammonia supplied by an ammonia storage tank, wherein the desulfurizing step generates desulfurization absorption solution containing ammonium sulfite;
• 4) removing absorption solution droplets from the desulfurized tail gas by washing the desulfurized tail gas with water in a water washing layer above the absorption section in the absorber:
• 5) removing droplets from the desulfurized and washed tail gas by treating the desulfurized and washed tail gas with a demister above the water washing layer inside the absorber;
• and
• 6) oxidizing the desulfurization absorption solution produced in step 3) by treating the desulfurization absorption solution in an oxidation section in the absorber set under the absorption section of the absorber, wherein said oxidation section contains oxidation distributors to oxidize ammonium sulfite in the desulfurization absorption solution to ammonium sulfate.