Desulfurization slurry dechlorination technology

Abstract

The invention relates to a desulfurization slurry dechlorination method and belongs to the coal-fired flue gas processing field. Further, for removal of chloride ions in flue gas desulfurization slurry obtained through ammonium sulfate-limestone method, a mode is employed that the desulfurized gypsum dewatering filtrate is supplemented with ammonium sulfate and then is subjected to electrolysis, hydrogen and chlorine are released directly, chlorine is released further through a stirred tank, the filtrate for dechlorination is sent back to an absorbing tower, and therefore the chlorine content in the slurry is lowered. The beneficial effects are as follows: firstly, instead of direct slurry dechlorination, desulfurized gypsum dewatering filtrate is subjected to dechlorination, and interferences of desulphurization intermediates in desulfurization slurry to dechlorination are avoided; secondly, after the filtrate is concentrated through supplemented ammonium sulfate, an electrolytic method is employed directly for dechlorination and the flows are simple; thirdly, release of chlorine which is not released in time in an electrolytic bath is promoted with high-speed stirring of the stirred tank; fourthly, the problem of control of the chloride ion content in desulphurization slurry is solved well and waste water discharge is reduced.

Description

technical field [0001] The invention belongs to the field of boiler tail gas treatment. The present invention relates to a dechlorination process of desulfurization slurry, more specifically, for the removal of chloride ions in the ammonium sulfate-limestone method flue gas desulfurization slurry, the desulfurization gypsum dehydration filtrate is supplemented with ammonium sulfate and then electrolyzed, directly Hydrogen and chlorine are released, and chlorine is further released through a stirred tank, and the dechlorinated filtrate is sent back to the absorption tower, thereby reducing the chlorine content in the slurry. Background technique [0002] There are two main sources of chloride ions in the desulfurization slurry: one is that the chlorine contained in the coal is burned to form chlorides that enter the desulfurization tower with the flue gas, and enter the desulfurization slurry under wet washing; Chloride ions accumulate as they evaporate. [0003] Studies ha...

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Problems solved by technology

This kind of wastewater contains heavy metals such as mercury, which is very polluting to the environment.

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