Acid regenerated flue gas treatment method and system

Abstract

The invention relates to an acid regenerated flue gas treatment method and system. The system comprises an absorbing column, a waste acid washing column, a venturi washing column, a spraying cooling column, a secondary washing column, a dust collector and a discharge chimney which are connected in sequence through a flue gas pipeline. A waste acid spraying unit is arranged in the waste acid washing column; acid regenerated flue gas is cooled by a venturi preconcentrator; the cooled flue gas is subjected to acid absorption in the absorbing column; dust collection is performed via the waste acidwashing column; the flue gas with the dust removed is washed via the venturi washing column to remove part of dust and acid mist in the flue gas; secondary washing is performed via spraying cooling;discharging is carried out after dust collecting, especially treatment via a wet electric dust collector. The waste acid washing column preheats waste acid during flue gas dedusting, so that operational energy consumption of an acid regeneration system can be reduced; the process is reasonable, the treated flue gas may reach good discharge indexes, and the discharged flue gas can gain white mist removal.

Description

technical field [0001] The invention belongs to the technical field of hydrochloric acid waste liquid regeneration treatment, and in particular relates to an acid regeneration flue gas treatment method and an acid regeneration flue gas treatment system. Background technique [0002] Hydrochloric acid is an important industrial production product, widely used in cold rolling mills in the iron and steel industry, pickling section in the pipe industry, acid leaching system in the chemical industry, etching industry, etc. When the consumption of hydrochloric acid waste liquid is large, spray roasting method or fluidized bed method is generally used for treatment. The principle is: the concentrated waste acid liquid is sprayed into the high-temperature area of ​​the roaster (or other roasting equipment, such as a rotary kiln, etc.), and after high-temperature chemical heat treatment, the high-temperature roasting flue gas passes through the Venturi pre-concentrator (or other equi...

AI Technical Summary

Problems solved by technology

Some enterprises use graphite heat exchangers on the flue to cool down the high-temperature acid-containing flue gas. In the short term, these processes can achieve the effect of reducing the temperature of the flue gas to a certain extent and reduce the HCl content in the flue gas; but the flue gas The gas contains a certain amount of iron oxide powder dust. Long-term operation will cause the graphite block holes inside the graphite heat exchanger to be blocked by iron powder, which will seriously affect the heat exchange efficiency and normal use of the heat exchanger.

In addition, the heat exchange efficiency of the gas entering the heat exchanger is relatively low, often requires a large heat exchange area, and the equipment price is relatively high

Therefore, the above method can only reduce the content of HCl in the flue gas, and has no obvious effect on the dust content in the flue gas, and it is still difficult to continuously meet the ultra-low emission of 10mg / Nm 3 requirements, especially during a period of time before and after cleaning the acid gun, the dust emission concentration is relatively high

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