Ultra-pure water preparation system and method capable of preventing electrodeionization device from scaling

Abstract

The invention provides an ultra-pure water preparation system and method capable of preventing a electrodeionization device from scaling. The preparation system is mainly composed of a raw water pretreatment system, a reverse osmosis system and an electrodeionization system. The raw water pretreatment system comprises a raw water booster pump, a mechanical filter, an active carbon filter and a precision filter, raw water enters the booster pump through a pipeline, and the mechanical filter, the active carbon filter and the precision filter are sequentially connected to the back of the booster pump; the reverse osmosis system comprises a high-pressure pump and a first-grade reverse osmosis device which is composed of a membrane component, a membrane shell, a pipe valve and a control system; the electrodeionization system comprises a fresh water pump, an EDI membrane stack and a rectifier; a water producing tank arranged at the back of the first-grade reverse osmosis device is connected to the membrane stack through the fresh water pump, the rectifier provides an electric field to form a membrane stack electric current, ion exchange resin in the EDI membrane stack continuously removes anions and cations in water through ion exchange, and the ultra-pure water is produced.

Description

technical field [0001] The invention relates to an ultrapure water preparation system and method for preventing fouling of an electrodeionization device, and belongs to the technical field of ultrapure water preparation. Background technique [0002] Electrodeionization device to prepare ultrapure water technology is a membrane separation and desalination process that organically combines electrodialysis technology and ion exchange technology. The device for preparing pure water by electrodeionization is composed of positive electrodes, negative electrodes, cation exchange membranes, concentrated water chambers, anion exchange membranes, and fresh water chambers filled with ion exchange resins located at both ends. , Directional migration and resin regeneration. The electrodeionization device can perform deep desalination of pure water to prepare ultrapure water, without the need for acid-base chemical regeneration, and no regeneration wastewater discharge. It is an environ...

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Problems solved by technology

The design of this countercurrent operation mode requires that the concentrated water cannot be circulated, so the ion concentration in the process of the membrane stack is low, the concentration distribution is very uneven, its resistance is high and the distribution is uneven, the operating voltage is high and the current is biased, which affects desalination Effect and water quality of produced water; and cause the increase of fresh water inlet pressure and increase the energy consumption of water pump operation. Therefore, filling ion exchange resin in the concentrated water chamber improves its electrical conductivity, but this increases the complexity of the structure of the EDI membrane stack;

[0006] The other is to add a porous membrane in the concentrated water chamber and divide it into two compartments, such as Chinese patent CN101195081B; the concentrated water chamber adds a porous membrane and divides it into two compartments to design the anion that migrates into the concentrated water chamber. Separated from cations, theoretically reduces the mixing of anions and cations and avoids the formation of scale in the concentrated water chamber, but the design of this compartment method increases the complexity of the structure, increases the resistance and voltage, and easily causes water flow deviation. Actual use performance needs to be tested

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