Tail gas purification system and process for spray roasting hydrochloric acid regeneration apparatus

Abstract

The invention provides a tail gas purification system and a process for a spray roasting hydrochloric acid regeneration apparatus. A waste acid scrubbing tower is arranged for removing the Fe2O3 dustin the tail gas, cooling the tail gas, preheating the waste acid, and saving energy consumption. A wet electrostatic precipitator is arranged, the concentration of Fe2O3 in the tai gas is guaranteed to be lower than 10 mg / Nm3, and the national ultra-low emission standard is reached; and compared with the mechanical defogging and dust removal equipment such as wire mesh defogger and the like, the wet electrostatic precipitator cannot generate the mesh blockage problem, the energy consumption can be effectively reduced, the micron-sized droplets carried in the tail gas can also be effectively removed, and thus the tail gas "white elimination" function is realized. A venturi scrubber and a quenching tower are arranged, the HCl removal rate in the tail gas can be improved by a large margin under the premise of reducing the use amount of fresh desalinated water by a large margin, the HCl concentration of the tail gas is ensured to be controlled within 10 mg / Nm3, the flow of a produced condensate liquid is adjusted by controlling the temperature of the gas of a quenching tower outlet, the effect of tail gas cooling by the quenching tower is achieved, and no waste water is produced.

Description

technical field [0001] The invention relates to the field of spray roasting hydrochloric acid regeneration devices, in particular to a tail gas purification system and process for spray roasting hydrochloric acid regeneration devices. Background technique [0002] Iron and steel, mechanical processing, and chemical companies generally use hydrochloric acid to remove oxidized rust on the surface of steel parts (steel coils, steel plates, steel pipes, etc.). The chemical reactions that occur during the treatment of steel parts with hydrochloric acid are as follows: [0003] Fe 2 o 3 +6HCl=2FeCl 3 +3H 2 o [0004] FeO+2HCl=FeCl 2 +H 2 o [0005] Therefore, the main component of pickling waste liquid is FeCl 2 , FeCl 3 Solution, at present, hydrochloric acid waste liquid generally adopts the spray roasting process to regenerate the waste acid. [0006] Such as figure 1 As shown, the principle of the spray roasting regeneration process is: the waste acid first enters t...

AI Technical Summary

Problems solved by technology

In order to ensure compliance with environmental protection standards, some enterprises can only increase the amount of fresh desalted water, which undoubtedly causes a great waste of resources and runs counter to the "energy saving and emission reduction" policy advocated by the state

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