Device and method for decomposing chlorate generated by side reaction of anode chamber of electrolytic cell in chlor-alkali production and related acid adding process

Abstract

The invention provides a device and method for decomposing chlorate generated by side reaction of an anode chamber of an electrolytic cell in chlor-alkali production and a related acid adding process.According to the method, an acid process for an electrolysis system is creatively improved, and the high peracid content is utilized to enhance the chlorate oxidation electrode potential and enhancethe reaction temperature, thereby greatly enhancing the decomposition speed and decomposition efficiency of the chlorate, completely decomposing the chlorate in the light salt brine into Cl2, Cl <-> and H2O at one time, avoiding the unstable gas ClO2 in the gas phase, and directly merging the pure wet Cl2 into a main pipe. The peracid content in the light salt brine after chlorate decomposition isutilized to replace light salt brine for dechlorination and acidification, thereby saving the self-used hydrochloric acid and caustic soda for electrolytic production. In the actual electrolysis operation, the decomposed chlorate can be balanced with the byproduct chlorate of the electrolytic bath at any time, so that the chlorate enriched in the electrolysis system can be quickly reduced, the problems of chlorate enrichment in the electrolysis system, influence on caustic soda quality, strong corrosion to solid caustic soda equipment and the like are solved, and the technical progress of chlor-alkali electrolysis production is greatly promoted.

Description

technical field [0001] The invention belongs to the field of brine electrolysis production technology (including NaOH and KOH production) in the chlor-alkali industry, and specifically relates to an ion membrane caustic soda electrolysis process that eliminates chlorate produced by side reactions in the anode chamber and converts it into reusable chlorate. Sodium and chlorine production technology. Background technique [0002] The production of caustic soda by ion membrane electrolysis of salt water is the most important production process in the existing chlor-alkali industry. During the electrolysis process, chlorate will be produced as a by-product in the anode chamber. The continuous accumulation of chlorate in brine will not only affect the solubility of NaCl , And the content of chlorate in the product NaOH also can increase, and quality declines. [0003] Under the action of direct current, its basic chemical reaction: [0004] 2NaCl+2H 2 O→2NaOH+Cl 2 ↑+H 2 ↑; ...

AI Technical Summary

Problems solved by technology

[0016] ① The process configuration of the chlorate decomposition device is complicated, and the steam is directly passed into the reaction solution, which pollutes the light brine;

[0017] ②It takes more than 2.5 hours to decompose, and the decomposition rate is 50% to 65% low. When the ion membrane of the electric cell runs to the late stage and the current efficiency is low, the chlorate in the brine can only run beyond the standard, and the production and operation of the brine and electrolysis system deteriorate;

[0019] ④ClO is contained in the chlorine gas produced when the decomposition starts at low temperature or when the amount of hydrochloric acid is insufficient 2 , cannot produce high-purity chlorine and send it to the downstream process, it can only be diluted with air (to prevent the generation of ClO 2 Decomposition explosion) as waste gas treatment, will also increase waste chlorine gas treatment facilities and operating costs;

[0020] ⑤This chlorate decomposition is a partial decomposition, incomplete chemical reaction

[0024] ① The chlorate decomposition device has added storage equipment, metering pump chemical addition equipment, etc., the operation is more complicated, and the decomposition effect is often not obvious when the medicine is mixed unevenly;

[0026] ③ The cost of purchasing medicines from suppliers is high, and a large number of purchased medicines are used to increase production costs;

[0027] ④ The composition of the strong reducing agent is unknown, and unknown substances are brought into the production system, and the generated substances need to be discharged from the electrolysis system, and there are certain risks in electrolysis production;

[0038] In short, the current mainstream chlorate decomposition methods in the chlor-alkali industry are far from reaching the optimal process control index for chlorate decomposition

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