Flue gas integrated treatment device and method

Abstract

An integrated flue gas treatment device and method. The device comprises a flue gas treatment device, an ozone supply device, a hydrogen peroxide supply device, an evaporation and concentration device, a circulating sedimentation device, etc., wherein the flue gas treatment device comprises an ozone spray oxidation reaction layer (82), a hydrogen peroxide spray oxidation reaction layer (92), an absorption spraying area (6), a slurry circulation area and a dedusting and demisting area, both of the ozone spray oxidation reaction layer (82) and the hydrogen peroxide spray oxidation reaction layer (92) being arranged in the absorption spraying area (6); the dedusting and demisting area is located above the absorption spraying area (6); and both of the evaporation and concentration device and the circulating sedimentation device are arranged in the flue gas treatment device.

Description

technical field [0001] The present invention relates to an integrated treatment device and method for flue gas, especially a device and method for simultaneously removing sulfur dioxide, nitrogen oxides, mercury and dust in flue gas, and using the waste liquid to produce magnesium sulfate and magnesium nitrate by-products . Background technique [0002] Industrial flue gas contains a large amount of dust, sulfur dioxide (SO 2 ), nitrogen oxides (NO X ) and other harmful substances, which are the main precursors and important sources of acid rain and smog. Elemental mercury (Hg 0 ) is the only toxic heavy metal that is gaseous at normal temperature and pressure. It has the ability to diffuse over long distances and is a global pollutant. Although the mercury content in industrial flue gas is very low, its harm to the environment cannot be ignored due to the large amount of flue gas. Therefore, the control of SO in industrial flue gas 2 , NO X , mercury and dust emissio...

AI Technical Summary

Problems solved by technology

[0011] Since the traditional magnesium oxide desulfurization waste liquid production technology uses steam as the medium for evaporation, crystallization and drying, the method of producing magnesium sulfate from desulfurization waste liquid needs to consume more steam, which directly increases the operating cost of desulfurization

CN1733656A discloses a method of utilizing boiler flue gas to produce magnesium sulfate heptahydrate fertilizer, wherein the magnesium sulfate solution adopts concentrated crystallization, that is, utilizes the characteristic that the solubility of magnesium sulfate decreases when the temperature exceeds 60° C., and this high-temperature crystallization method requires Consumes more high-quality steam and will cause frequent blockage of the slurry delivery pipeline, making it difficult to achieve continuous and stable production of by-products

This method of evaporation and crystallization requires high steam quality, and if low-grade steam is used, the consumption will increase

The process disclosed in the above patent documents requires about 1.2 to 2 tons of steam to produce one ton of magnesium sulfate. The steam price is calculated at 80 yuan / ton, and the steam consumption cost of one ton of magnesium sulfate is about 160 yuan.

Therefore, although the comprehensive cost of magnesium desulfurization is lower than that of calcium desulfurization, the current way of producing magnesium sulfate by using three-effect evaporation outside the magnesium desulfurization tower still wastes steam resources, and the desulfurization operation cost is still high

Moreover, due to the influence of dust and other impurities in the flue gas, the magnesium sulfate impurity content produced by the direct production of magnesium sulfate in the general tower is relatively high, and it is difficult to separate later, which affects the quality of magnesium sulfate.

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