Hydrochloric acid waste liquid regeneration flue gas treatment system and operation method thereof

Abstract

The invention relates to a hydrochloric acid waste liquid regeneration flue gas treatment system. The hydrochloric acid waste liquid regeneration flue gas treatment system comprises a venturi preconcentrator, an acid absorption tower and a washing mechanism which are sequentially connected through a flue gas pipeline, and further comprises a dynamic wave washer arranged between the venturi preconcentrator and the acid absorption tower or between the acid absorption tower and the washing mechanism. The invention further relates to an operating method of the system. The dynamic wave washer is arranged between the venturi preconcentrator and the acid absorption tower or between the acid absorption tower and the washing mechanism; based on the characteristics and advantages of the dynamic wavescrubber, close contact between dust in flue gas and circulating acid liquor is achieved, the acid dissolution effect on fine dust is enhanced through the circulating acid liquor, the efficient dustremoval effect can be achieved, and therefore the treatment effect and efficiency of hydrochloric acid waste liquor regeneration flue gas are remarkably improved.

Description

technical field [0001] The invention belongs to the technical field of hydrochloric acid waste liquid regeneration, and in particular relates to a hydrochloric acid waste liquid regeneration flue gas treatment system and an operation method thereof. Background technique [0002] Spray roasting treatment of cold-rolled strip pickling waste is currently the most widely used hydrochloric acid regeneration process, and the specific reaction formula is as follows: [0003] 4FeCl 2 +4H 2 O+O 2 =2Fe 2 o 3 +8HCl [0004] Most of the solid particles of iron oxide powder fall into the conical part of the lower part of the roasting furnace 1 and are discharged through the bottom of the furnace, while the high-temperature reaction gas is discharged from the top of the roasting furnace 1, and the main components are gas combustion products, water vapor, HCl, and a certain amount Fe 2 o 3 dust. Such as figure 1 , in the conventional process, the high-temperature flue gas at the ...

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Problems solved by technology

Purification by the above process can make the dust and acid mist in the exhaust flue gas reach 30-50mg / Nm respectively 3 standards, but it is difficult to meet the ultra-clean emission standards for flue gas in high-standard areas (10mg / Nm 3 the following)

[0005] In addition, a common technical problem in the production of the above-mentioned process is that the spray roasting process is divided into two modes: acid operation and water operation according to the materials entering the Venturi pre-concentrator 3, and the acid operation enters the Venturi pre-concentrator 3 The material used is waste acid, and the material entering the Venturi pre-concentrator 3 during water operation is rinsing water; when the unit switches between water operation and acid operation, the exhaust gas emitted from the chimney appears red because it contains a large amount of iron oxide dust , known as the red smoke phenomenon in the industry

[0006] The reason for the above phenomenon is that during the switching from acid operation to water operation, the waste acid solution FeCl in the Venturi pre-concentrator 3 2 The concentration is reduced, resulting in the Fe generated by the roaster 1 2 o 3 Particles become smaller, double cyclone dust removal effect and physical adsorption effect become worse; at the same time, the amount of hydrogen chloride gas in the roaster 1 decreases, the concentration of free acid in the Venturi pre-concentrator 3 and the absorption tower decreases, and the chemical solubility of iron oxide dust decreases. , the combined action of these factors makes the content of iron oxide powder in the exhaust gas emitted from the chimney increase, resulting in the phenomenon of red smoke

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