Removing and recovering process and device for SO2 in flue gas

Removing and recovering process and device for SO2 in flue gas

  • CN 1,408,464 A
  • Filed: 09/09/2002
  • Published: 04/09/2003
  • Est. Priority Date: 09/09/2002
  • Status: Active Application
First Claim
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1. SO in flue gas2The removal and recovery method is characterized by comprising the following steps:

  • (1) firstly, reacting low-sulfur flue gas with an ammonium sulfite solution to generate a mixed solution of ammonium sulfite and ammonium bisulfite, wherein the ammonia/sulfur ratio is 1.3-1.8 (molar ratio), and the gas/liquid ratio is 2000-5000 (volume ratio), and then adding ammonia to react to generate an ammonium sulfite solution, wherein the ammonia comprises liquid ammonia, ammonia water or/and ammonium bicarbonate;

    (2) carrying out oxidation reaction on the generated ammonium sulfite solution and air to obtain an ammonium sulfate solution, wherein the pressure of compressed air is 0.05-0.2Mpa, the flow of the compressed air is 1-5 times of the theoretical required amount of ammonium sulfite oxidation, and the retention time of the oxidation reaction is 1-3 hours;

    (3) contacting the ammonium sulfate solution generated in the step (2) with hot flue gas, and sending the ammonium sulfate solution with evaporated moisture to an ammonium sulfate crystallizer to be processed into a commercial ammonium sulfate fertilizer;

    (4) for absorbing SO by ammonia water solution2Washing the flue gas with water;

    (5) and defoaming the flue gas after washing.

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