The invention relates to a recycled
flue gas desulfurization and denitration method, which sequentially comprises the following steps of: introducing
flue gas of SO2 and
NOx into a desulfurizing
tower, and absorbing the SO2 with a desulfurizing agent (barren liquor) in the desulfurizing
tower; desorbing the desulfurizing agent (rich liquor) which absorbs the SO2 through a multi-effect
evaporator,releasing the SO2 gas, and concentrating the SO2 gas into liquid SO2 through condensation
drying; making the desulfurized
flue gas enter a denitration
tower, injecting
gaseous ozone from an
ozone generator, oxidizing the NO in the
flue gas, absorbing the oxidized NO by using a denitrifier to form
nitrate; crystallizing and separating out the
nitrate in the solution after the
nitrate reaches certain concentration, and filtering and
drying to obtain the nitrate product. The method turns the wastes into wealth, and the SO2 and
NOx in the
flue gas are recycled by higher-additional value liquid SO2 and nitrate products, so that the recycling and value maximization in the desulfurization and denitration process is realized. Due to the adoption of the technical scheme, the high desulfurization and denitration rate can be achieved, the desulfurization rate is over 96 percent, the denitration rate is more than 90 percent, and the purity of the nitrate product is over 96 percent. The method hasthe advantages of simple desulfurization and denitration process, low investment, and low operation cost for desulfurization and denitration, and solves the problems that the conventional desulfurization and denitration process has high cost, generates a
side product of a mixture of
sulfuric acid (
sulfate) and
nitric acid (nitrate), and has low additional value.