Method for desulfurizing high-sulphur boiler flue gas to prepare high-purity ammonium bisulfite

Abstract

The invention relates to a method for removing and recycling SO2 in high-sulphur boiler flue gas and discloses a method utilizing ammonia water as material and recycling desulfuration to prepare ammonium bisulfite with high SO2 / NH3 value and high purity. The method comprises the steps of (1) performing dry dedusting on high-sulphur boiler flue gas, and cooling through wet dust collection, (2) utilizing ammonia water as absorbents to absorb SO2 in flue gas in a triple tandem desulfurizing absorption tower, controlling the absorbing temperature through an exterior circulation cooling mode, preparing ammonium bisulfite solution with high SO2 / NH3 value, and discharging with standard level after water scrubbing and demisting, (3) removing high chemical valence insoluble heavy metal ions such as ferric iron through microfiltration, and (4) removing heavy metal ions through chelating ion exchange resins to obtain products. According to the method, the concentration of SO2 in flue gas after desulfurization is low, SO2 in high-sulphur boiler flue gas is effectively recycled, and ammonium bisulfite solution with high SO2 / NH3 value and high purity is prepared.

Description

technical field [0001] The present invention relates to a method for removing and recovering SO2 in flue gas from a high-sulfur boiler, in particular to a method for preparing high-SO2 by using ammonia water as raw material for desulfurization and recovery. 2 / NH 3 value, high-purity ammonium bisulfite method. Background technique [0002] SO in the flue gas of high-sulfur coal, fuel oil and fuel gas boilers 2 Governance is a difficult problem in desulfurization. Although the traditional limestone method, double alkali method and other desulfurization processes can meet the discharge standards, they have the disadvantages of large consumption of alkali absorbents and high operating costs. The traditional ammonia method has many by-products recovered with impurities and poor quality. Disadvantages of added value of ammonium sulfate. Based on the concept of circular economy, the SO in the high-sulfur boiler flue gas 2 Starting from resource utilization and high value-add...

AI Technical Summary

Problems solved by technology

[0011] Smelting and Sintering Gas Desulfurization and Recovery of SO 2 Acid production is to remove dust and purify the sintering flue gas by going through two stages of power wave washing, one stage of empty tower cooling, one stage of power wave washing, and two stages of electrostatic demisting, but there are complex processes and high investment costs. , High power consumption and other disadvantages

[0012] The previous ammonia desulfurization absorption towers used empty towers, bubble towers, and grid towers, which had disadvantages such as low absorption efficiency, large liquid-gas ratio, high ammonium salt oxidation rate, or large resistance.

[0013] The previous ammonia desulfurization tail gas did not wash the ammonia recovery section. Generally, a dehydration and demisting device with two baffles was used. The water in the tail gas was serious, the dehydration resistance was large, the dehydration and demisting efficiency was low, and the loss of ammonia escape was large. Affect the environment, the investment cost of wet electrostatic precipitator is very high, and the operation cost is high

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