Process and device for flue gas wet desulphurization using carbide slag or white clay as desulfurizing agent

Abstract

The invention discloses a process and device for flue gas wet desulphurization by using carbide slag or white clay as desulfurizing agent, and belongs to the field of air pollution control. The wet desulphurization device comprises an absorption tower, a slurry pool and gypsum dehydration equipment, wherein a demisting layer, a spraying layer, a flue gas absorbing zone and a slurry tank are arranged in sequence from up down inside the absorption tower; the flue gas absorbing zone is provided with a flue gas inlet; the wet desulphurization device further comprises a separation tank in which a stirrer is arranged; the separation tank is communicated with the absorption tower through a drainage tube; the drainage tube is positioned below the flue gas inlet; the inlet end of the drainage tube is inclined upward and extends into the flue gas absorbing zone; a notch is formed at the part of the drainage tube in the flue gas absorbing zone and in parallel to the axial line of the drainage tube and forms an upward-opening recess; the lower part of the separation tank is communicated with the gypsum dehydration equipment; and the upper part of the separation tank is communicated with the slurry pool. The device is applied to flue gas wet desulphurization. The gypsum slurry is pretreated before dehydration, so that the gypsum layer separates from the solution layer and the colloidal substance layer, which increases the purity of gypsum, reduces the water content of gypsum and improves the quality of gypsum.

Description

technical field [0001] The invention relates to the technical control field of air pollution, in particular to a flue gas wet desulfurization process and device using calcium carbide slag or white mud as a desulfurizer. Background technique [0002] At present, hundreds of desulfurization technologies have been developed and applied at home and abroad. These desulfurization methods can be roughly divided into three categories: dry method, semi-dry method and wet method. Among them, the limestone-gypsum desulfurization process in the wet desulfurization process has the advantages of High desulfurization efficiency, good stability, and the by-product of desulfurization is gypsum, which can realize the resource utilization of desulfurization products, so it has been widely promoted. [0003] The limestone-gypsum desulfurization process accounts for about 90% of the total desulfurization units under construction and built in the world. The limestone-gypsum method uses natural l...

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Problems solved by technology

However, white mud also contains reducing substances such as phosphides and sulfur anions, which can easily prevent the oxidation of calcium sulfite. At the same time, due to the presence of sodium ions, the pH value of the slurry rebounds quickly, which easily leads to scaling and blockage of the slurry inside the nozzle and equipment. equipment

[0008] Because calcium carbide slag and lime mud contain many complex components, calcium carbide slag and lime mud cannot be directly applied to the device of limestone-gypsum desulfurization process

Al contained in carbide slag and lime mud 2 o 3 , SiO 2 During the desulfurization process, colloidal suspensions such as calcium silicate and aluminum hydroxide will be formed to fill the entire slurry system. After these colloidal suspensions enter the belt filter with gypsum, a dense film will be formed on the surface of the gypsum. The air permeability of the gypsum cake is reduced, making it difficult to dehydrate the belt filter, resulting in a high moisture content of the gypsum after dehydration, and the heavy metals contained in the water in the slurry are also attached to the inside, which affects the use value of the desulfurized gypsum

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