Technique for preparing magnesium sulfite during magnesium method desulfurization process

Abstract

The invention discloses a preparation method of magnesium sulfite during the desulphurization with magnesium oxide, which is capable of reducing the system water consumption and improving the yield of the magnesium sulfite. The preparation method includes: (1) removing impurities: guiding fume containing sulfur dioxide into a pretreatment device, removing partial fine powder dust, the hydrogen chloride and the hydrogen fluoride from the fume in the pretreatment device with atomized water sprayed from a spraying device, and loading the fume to a desulfurizing tower; (2) desulfurizing: allowing thje sulfur dioxide in the fume and the magnesium hydroxide slurry to react in the desulfurizing tower so as to remove the sulfur dioxide from the fume and further arranging the oxidation inhibitor simple substance or the sodium thiosulfate in order to prevent oxidation of the generated magnesium sulfite by the oxygen in the fume to obtain magnesium sulfate; and (3) separating: flocculating and settling the desulfurized slurry to obtain sediment, and performing the solid-liquid separation to obtain dried magnesium sulfite byproducts.

Description

technical field [0001] The invention relates to a preparation process of magnesium sulfite in the magnesium method desulfurization process. Background technique [0002] Magnesium oxide wet desulfurization process (abbreviation: magnesium desulfurization) uses magnesium oxide (MgO) as raw material to produce magnesium hydroxide (Mg(OH) 2 ) as a desulfurizer, an advanced, efficient and economical desulfurization process for desulfurizing boiler flue gas, the steps include: [0003] ① Removal of impurities: the flue gas containing sulfur dioxide is introduced into the pretreatment device, and part of the fine dust, hydrogen chloride, hydrogen fluoride and sulfur trioxide in the flue gas are removed when passing through the atomized water sprayed by the spray device in the pretreatment device, Then the flue gas is sent to the desulfurization tower; [0004] ②Desulfurization: The sulfur dioxide in the flue gas reacts with the magnesium hydroxide slurry in the desulfurization t...

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Problems solved by technology

[0007] The disadvantage of the above process is: the solubility of magnesium sulfate generated in the desulfurization process is extremely high, and it is difficult to achieve solid-liquid separation. On the one hand, the water in the by-product slurry is not recycled, and the system consumes a lot of water, which increases the production cost. On the other hand, the magnesium sulfate that is not separated is discarded, which reduces the output of by-products and causes a serious waste of resources

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