A kind of chlor-alkali brine purification device and its purification process

Abstract

The invention discloses a chlor-alkali brine purifying device and a purifying technology thereof. A pump is connected with the upper inlet of a pressure tank through a check valve, the bottom outlet of the pressure tank is connected with the inlet of a mixing reactor A, the outlet of the mixing reactor A is connected with the top inlet of a membrane filter, the outlet of the membrane filter is connected with the inlet of a mixing reactor B, the outlet of the mixing reactor B is connected with the top inlet of a resin tower, the outlet of the resin tower is connected with the middle inlet of agas-liquid separator, a gas discharged from the top gas outlet of the gas-liquid separator is mixed with air and then is sent into the inlet of a compressor, the top outlet of the gas-liquid separatoris also connected with a purifier, and the outlet of the compressor is connected with the top inlet of the pressure tank. The problem of severe obstruction of a filter cake by a compacted filter membrane, caused by rapid rising of the pressure during pressure supply directly using a pressure pump, is avoided in order to effectively save energy; and sediments are prevented from adhering to the inner wall of the pump in order to prolong the service life of the pump.

Description

technical field [0001] The invention belongs to the technical field of chlor-alkali brine purification, and in particular relates to a chlor-alkali brine purification device and a purification process thereof. Background technique [0002] In the chlor-alkali production process, a large amount of raw salt is required, and the raw salt contains a certain amount of SO 4 2- , Ca 2+ , Mg 2+ If these ions are not removed, precipitation will be generated during the electrolysis process, which will cause damage to the electrolysis device. [0003] The removal method of these ions is usually to add the corresponding precipitant to make it precipitate: where SO 4 2- , Ca 2+ The sediment can be removed by settling equipment, but the settling equipment often takes up too much land and the settling speed is very slow, so the efficiency is too low, and it is easy to have insufficient settling, and the incompletely purified brine flows into the next process to cause production probl...

AI Technical Summary

Problems solved by technology

[0002] In the chlor-alkali production process, a large amount of raw salt is required, and the raw salt contains a certain amount of SO 4 2- , Ca 2+ , Mg 2+ If these ions are not removed, precipitation will be generated during the electrolysis process, which will cause damage to the electrolysis device

[0003] The removal method of these ions is usually to add the corresponding precipitant to make it precipitate: where SO 4 2- , Ca 2+ The sediment can be removed by settling equipment, but the settling equipment often takes up too much land and the settling speed is very slow, so the efficiency is too low, and it is easy to have insufficient settling, and the incompletely purified brine flows into the next process to cause production problems ;Mg 2+ The precipitate is flocculent and extremely difficult to settle. Some processes are used to remove Mg 2+ The sediment, dissolve a certain amount of air in the crude brine under a certain pressure, and then suddenly release the pressure, so that the Mg 2+ The flocculent sediment floats up with the air bubbles, and then the Mg 2+ This process is complex, and the process of first pressurizing and then releasing the pressure will inevitably cause a certain amount of energy waste

[0004] Patent CN200610038868.6 proposes that Ca 2+ , Mg 2+ , SO 4 2- Wait for the reaction to form a precipitate, then add coagulation aids such as sodium polyacrylate, polyacrylamide or causticized starch, and remove Mg through adsorption and co-precipitation 2+ The sediment and other solid particles, although this process is improved compared with the dissolved air method, but the settling speed and settling efficiency are still unsatisfactory, and the equipment occupies a large volume

Moreover, this process directly pumps the brine after the precipitation is removed into the membrane filter. As the filtration progresses, a certain filter cake will be formed, making the filtration difficult, and the outlet pressure of the pump will rise rapidly, and the efficiency of the pump will increase. Reduced, the filter cake becomes more solid under high pressure, which makes the membrane pores of the filter membrane clogged more seriously, and the filter membrane needs to be washed frequently, which reduces the service life of the membrane and affects the smooth progress of production

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