Chlorate decomposition process method in ionic membrane caustic soda production

Abstract

The invention discloses a chlorate decomposition process method in ionic membrane caustic soda production. The process method includes steps of: conveying the light salt brine from the chlorate heat exchanger to the outlet of the chlorate decomposing tank to an electrolytic anode circulating tank by a chlorate pump; then directly conveying the brine to a light salt brine pipeline for protecting arefined brine main pipe; adding the salt brine into a saturated refined brine main pipe under the control of a flow meter, an acid concentration meter and a regulating valve; conveying the salt brineto a dechlorinating tower from an electrolytic anode circulating tank through an electrolytic anode circulating pump, conveying the salt brine to a light salt brine pipeline for protecting a refined brine main pipe, and conveying the salt brine to a chlorate decomposing tank; subjecting the light salt brine conveyed to the dechlorination tower to vacuum physical dechlorination and chemical dechlorination by the water ring vacuum pump unit; conveying the salt brine to primary salt brine treatment step; dispensing the brine passing through the saturated refined brine header pipe to each electrolytic cell, and then electrolyzing the brine distributed to each electrolytic cell. According to the invention, after part of the strong-acidity light brine at the chlorate outlet is directly added into the circulating tank, the strong-acidity light brine at the chlorate outlet can be fully mixed with the light brine at the outlet of the electrolytic cell, and the dechlorination system is more stable to control.

Description

technical field [0001] The invention relates to a chlorate production process in the field of industrial ion membrane caustic soda production, in particular to a chlorate decomposition process in the ion membrane caustic soda production. Background technique [0002] At present, the known ion membrane caustic soda production process technology is very mature. Ionic membrane caustic soda production runs for a long period of time without interruption. The brine in it will produce chlorate in the whole system, and the chlorate will continue to accumulate. If the concentration is high, the concentration of sodium chloride in the brine will decrease, which will affect the electrolysis. The current efficiency of the cell and the amount of electrolyte, chlorate is more harmful to the entire electrolysis system, seriously affecting production safety and high efficiency. Part of the light brine (NaCl concentration: 205-230g / L) at the outlet of the electrolytic anode circulation pump...

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Problems solved by technology

[0003] 1. Because the acidity of the acidic light brine at the outlet of the chlorate decomposition tank device is relatively high, it is added to the inlet of the dechlorination tower and mixed with the electrolytic undechlorinated light brine (2≤PH≤4), because the dechlorination tower has a PH index requirement (1.1≤PH ≤1.5), the flow rate of the chlorate decomposition device cannot be increased, otherwise the pH at the inlet of the dechlorination tower will exceed the standard, and the strong acid brine will cause hidden dangers to the dechlorination equipment

[0004] 2. When the ionic membrane runs to the later stage, the chlorate generated by the side reaction of the electrolytic cell increases, but the decomposition flow rate of the chlorate decomposition device is limited and cannot be increased any more. The chlorate content in the brine system increases, and the chlorate in the liquid caustic soda The salt content also increases, which affects the quality of liquid caustic soda products. Chlorate also causes corrosion damage to the equipment of the subsequent caustic soda evaporation plant, which increases the maintenance cost of equipment and affects the economic benefits of the chlor-alkali system.

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