The invention relates to the field of
environmental protection and discloses a three-cycle desulphurization method for wet type
ammonia-process desulphurization. The desulphurization method is implemented with a first
slurry circulating loop, a second
slurry circulating loop and a third
slurry circulating loop, wherein in the first slurry circulating loop, slurry having
mass concentration of 10%-20% and a pH value of 4.0-5.0 is used for carrying out cycle spraying treatment on
flue gas, and the temperature of the
flue gas treated by the slurry is 50-60 DEG C; in the second slurry circulating loop, slurry having
mass concentration of 10%-15% and a pH value of 5.0-6.0 is used for carrying out cycle spraying treatment on the
flue gas; and in the third slurry circulating loop, slurry having
mass concentration of 3%-10% is used for carrying out cycle spraying treatment on the
flue gas. The invention also discloses a
flue gas desulfurization
tower or
system using the three-cycle desulphurization method. According to the three-cycle desulphurization method, the three independent circulating loops are divided according to the concentration of the slurry, the circulating loops separately control the slurry having different concentrations and pH values for treatment of the
flue gas, and the contradiction of high desulphurization efficiency and high
oxygenation efficiency of by-products is solved.