Method for comprehensively utilizing chlorination tail gas in chlorination-process titanium dioxide powder production procedures

Abstract

The invention relates to a method for treating chlorination tail gas in chlorination-process titanium dioxide powder production procedures. Carbon monoxide in the chlorination tail gas can be used as a heat source, and byproduct hydrochloric acid which is obtained after the chlorination tail gas is subjected to acid pickling can be desorbed to obtain high-purity hydrogen chloride by the aid of the method. The method includes carrying out acid pickling and alkali washing on the chlorination tail gas, then combusting the chlorination tail gas in a combustion furnace, feeding generated hot flue gas into a reboiler and ultimately venting the flue gas; filtering the byproduct hydrochloric acid obtained after the chlorination tail gas is subjected to acid picking, carrying out heat exchange on the byproduct hydrochloric acid, then feeding the byproduct hydrochloric acid into a desorption tower, continuously heating and evaporating the byproduct hydrochloric acid by the aid of a reboiler to obtain hydrogen chloride gas, exhausting the hydrogen chloride gas from the top of the desorption tower and draining evaporated diluted hydrochloric acid from the bottom of the desorption tower; carrying out heat exchange on the diluted hydrochloric acid by the aid of a double-effect heat exchanger and cooling the diluted hydrochloric acid until the temperature of the diluted hydrochloric acid reaches the normal temperature; condensing the hydrogen chloride gas to obtain high-purity hydrogen chloride gas. The method has the advantages that carbon resources can be effectively utilized; the recycled hydrochloric acid can be converted into the high-purity hydrogen chloride, and accordingly the resource utilization rate can be increased; the desorbed diluted hydrochloric acid is used as acid pickling absorption liquid, accordingly, the recycling rate of the byproduct hydrochloric acid can be increased, discharge pressures can be relieved, and the production cost can be lowered.

Description

technical field [0001] The invention relates to a method for treating tail gas, in particular to a method for treating chlorinated tail gas in the production process of chlorinated titanium dioxide. Background technique [0002] Titanium dioxide is a white inorganic pigment with the best opacity, best whiteness, brightness and non-toxic properties. It is recognized as the best white pigment in the world. It is widely used in coatings, plastics, papermaking, Printing ink, chemical fiber, rubber, cosmetics and other industries. [0003] The production of titanium dioxide by the chlorination method is mainly to mix the titanium-rich raw materials with petroleum coke, and then carry out chlorination reaction in the chlorination furnace to form a mixture containing titanium tetrachloride, and the mixture from the top of the chlorination furnace is separated by a cyclone dust collector slag, dust, to obtain crude titanium tetrachloride; make the VOCl contained in the crude titani...

AI Technical Summary

Problems solved by technology

Regardless of the treatment methods of pickling, alkali washing, water washing, or alkali washing, the carbon monoxide contained in the exhaust gas after purification has not been effectively utilized, and it is directly discharged with the exhaust gas or emptied after combustion, and the combustion heat has not been rationally utilized, resulting in waste of carbon resources

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