Electrodeionization Also called salt technology in addition to continuous electricity, it scientifically will electrodialysis and ion exchange technique, the cation and anion membrane of cation and anion selective permeation and ion exchange resin of ions in water, to achieve directional migration of ions in water under the action of electric field, so as to achieve the depth of water purification salt, and the filling resin is continuously regenerated by hydrogen ions and hydroxyl ions produced by water electrolysis, so the process of EDI water without acid and alkali chemical regeneration can continuously produce high-quality ultra pure water, it has the advantages of advanced technology, compact structure, convenient operation, and can be widely used in electric power, electronics, medicine, chemical food, and laboratory areas, is the water treatment technology of the green revolution. This new technology can replace the traditional ion exchange device to produce ultra pure water with resistivity up to 16-18M Omega CM.
The working principle of EDI EDI: the working principle of equipment of high purity water is very important for many industrial and commercial projects such as the semiconductor industry and pharmaceutical industry. Previously, the pure water used for industry was obtained by ion exchange. However, membrane systems and membrane processes are becoming more and more popular as pretreatment processes or alternatives to ion exchange systems. Membrane systems such as electro demineralization (EDI) can remove minerals very cleanly and can work continuously. Moreover, the membrane treatment process is much simpler than the ion-exchange system, without the need for acid and alkali regeneration and wastewater neutralization. The EDI process is one of the fastest growing businesses in membrane processing. EDI with a special water tank, water flow path filled with mixed bed ion exchange resin. EDI is mainly used to make 8-17 1-20mg/L of pure water from the total dissolved solids (TDS). The EDI unit couples the ion exchange resin between the anion / cation exchange membrane to form the EDI unit. The working principle of EDI is shown in figure. The EDI component separates a certain number of EDI units from the mesh, forming a dense water chamber. A cathode / anode electrode is arranged at both ends of the unit unit. Driven by the direct current, the anions and cations in the water of the fresh water chamber pass through the cation anion exchange membrane respectively into the concentrated water chamber and are removed in the fresh water chamber. And through the water in the water chamber, the ions will be taken out of the system to become concentrated water. EDI equipment is generally used as reverse osmosis (RO) pure water as EDI water supply. RO pure water resistivity is generally 40-2 S/cm (25 degrees Celsius). EDI pure water resistivity can be as high as 18 M.Cm (25 DEG C), but according to deionized water use and system configuration settings, EDI pure water is applicable to prepare resistivity requirements at 1-18.2M.Cm (25 degrees Celsius) pure water.
The characteristics of EDI EDI devices do not need chemical regeneration, continuous operation, and does not require the traditional mixed ion exchange water treatment process of alkali liquid equipment required for regeneration, regeneration and wastewater emissions.
The structure characteristics of EDI module
1. Fresh water separator adopts sanitary PE material
2, EDI membrane adopts imported homogeneous film and domestic heterogeneous ion exchange membrane
3, the use of imported EDI special grain resin and domestic EDI special granules resin
4, EDI electrode plate adopts the technology of titanium ruthenium plating
5. The pressing plate is made of hard alloy aluminum rolling.
6 、 fixed screws adopt GB standard parts
7, membrane reactor factory maximum test pressure, 7bar is not leaking
8, film stack resistance is low, power consumption is small
9 、 the appearance board is beautiful and firm
10. The maximum film handling capacity is 3T/H, and the minimum reactor handling water quantity is 75L/H
11, pure water, dense water, and extremely water channel design is reasonable, not easy to plug, the current distribution is uniform, no dead angle.
The water requirement
The usually osmosis water single stage reverse osmosis or two stage reverse osmosis
The TEA (total exchangeable anion, CaCO3): 25ppm.
The electrical conductivity is less than 40 S/cm:
The PH:6.0 ~ 9. When the total hardness is lower than 0.1ppm, the optimum working range of EDI is from 8 to 9 pH.
The temperature: 5 ~ 35 degrees.
The inlet pressure: < 4bar (60psi).
The hardness: (CaCO3): 1.0ppm.
The organic matter (TOC): 0.5ppm.
The oxidizing agent: Cl2 < 0.05ppm < 0.02ppm, O3.
The valence metal: Fe < 0.01ppm < 0.02ppm, Mn. The H2S: 0.01ppm.
The silica: less than 0.5ppm.
The color: < 5APHA.
The total amount of carbon dioxide: 10ppm \ \ \ \ < < 1: SDI 15min. EDI is a revolutionary new type of "green desalination" ultra pure water preparation technology, is placed in the reverse osmosis system after the two desalination equipment, it can produce 15 ~ 18M Omega.CM ultrapure water
Regeneration of EDI module without any chemical reagent, can be run continuously. The regeneration operation, only need to adjust the current can be EDI. It is widely used in microelectronics, semiconductor, power plants, pharmaceutical and laboratory etc.. This product has the advantages of simple design, convenient operation, complete set of equipment in a frame body, only when the installation of electricity and water supply, modular design, easy to expand, with PLC automatic control, automatic operation, automatic monitoring and detection by automatic instrument system effluent quality, without human control, simple operation, small occupied area. According to our actual experience, combined with the current international and domestic advanced technology, we propose several treatment processes. The specific process must be determined according to the influent water quality and the effluent quality.
