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Home » Water » Industrial Water » Water Deionizers
Water Deionizers
Water Deionizers

Industrial Water Demineralizers and Deionizers

Wateen Solutions is a leading manufacturer of commercial & industrial water demineralizer plants (DM) / deionizer (DI). Obson DM equipments are designed for the economical and efficient removal of dissolved salts and minerals. These water treatment systems produce high purity water for commercial and industrial applications. Wateen Solutions designs and manufactures a complete line of DI systems to meet your water quality requirements.

 

Obson DM 's Deionizers
Obson DM Series two-bed deionizers are available as standard pre-engineered units or as custom designed systems with the flexibility to meet a wide range of requirements. These DI water systems can be manufactured with a full range of options and related equipment to provide fully integrated water purifications systems. Tanks range in size from 14" to 48" in diameter, with flows up to 188 gallons per minute. Obson-DM Series two bed deionizers are a highly efficient means of removing dissolved minerals and solids to produce high purity DI water.

 

DI Water System Features and Benefits
The Obson DM two-bed deionizers are designed for production of deionized water with conductivity of less than 10 microsiemens. Some of the key feautres are:

•    Strong acid cation and type 1 strong base anion resins as the standard, with other resins available as an option.
•    Microprocessor based control system with conductivity monitor and flow sensor for regeneration initiation.
•    Electrical enclosures are NEMA 4XFG corrosion resistant fiberglass, which reduces maintenance costs.
•    Resin vessels can be polyethylene-lined fiberglass or rubber-lined steel depending on size and customer requirements.
•    ASME code vessels.
•    Factory assembly and skid mounting for quick installation and minimum startup cost.
•    Schedule 80 PVC piping package including air operated composite plastic diaphragm valves is standard. Air or electric actuated ball or butterfly valves are available as an option.
•    Pressure regulators, rotameters and metering valves supplied for accurate and safe control of regeneration water and chemical introduction.
•    Internal distributors are corrosion resistant, designed for optimum efficiency and are fully supported where required.

Why use a Water Demineralizer / Deionizer?
The deionization process removes ions (cations and anions), dissolved solids and gases, including:

•    Sodium, calcium, and magnesium (cations)
•    Sulfates, alkalinity, chlorides, carbon dioxide, and silica (anions)

Deionization is accomplished by passing water through ion exchange columns containing cation and anion resins. Simply put, the result is water without ions minerals and salts.

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Applications for Industrial and Commercial DI Water Sytems
Strong base anion resin type units are used in the preparation of high purity water for boiler make-up process, laboratory and production requirements. These units work more efficiently where the TDS level of the water to be treated is less than 600 ppm. Wateen Solutions's units employ cation followed by anion resin in separate beds. They produce demineralize water with total mineral 4.0 ppm. Actual effluent quality vary based on chemical dosages utilized and actual influent water qualities.
Obson DM demineralizer make them ideally suited to treating water for high pressure (over 600 psi) boiler use. The low tolerances of these boilers to mineral build-up makes the strong base demineralizer a must for low blowdown waste and saving of both fuel and internal chemical treatment. The low silica contents produced by strong based demineralizers is specially important where is steam is used to drive turbines.
Manufacturing processes that add water directly to finished product, or washing and rinse operations where spot free drying is important, also used strong base demineralizers. Additional applications include metal plating, closed loop cooling water and clean air humidification, among others
The following facilities are examples of ideal applications for water demineralizer and deionizer (DI) equipment:

•    Hospital
•    Medical and Research
•    Laboratories
•    Car Wash Final Rinse
•    Painting and Plating Process
•    Pharmaceutical manufacturers
•    Photographic Processes
•    Food and Beverage Processing Plants
•    Power plants
•    Chemical plants
•    High pressure boiler feedwater
•    Manufacturing Plants
•    Plating printing
•    Metal workings
•    Fluid chemical blending
•    Humidification
•    Glass industries



Water Deionization (Demineralization)
Total Dissolved Solids (TDS) are the sum of all minerals compounds dissolved in the water. They consist primarily of salts of calcium, magnesium or sodium usually in the form of chlorides, sulphates or bicarbonates.
In such circumstances where these dissolved salts have any interference with the other process ingredients, they have to be removed form the water.
Demineralization by ion exchange is the removal of all minerals (inorganic salts) dissolved in water. The degree of removal depends on the exact process employed.

 

Process Theory
The strong base Obson DM demineralizer is a two vessels system. Water first passes through a strong acid cation exchange vessel, where the ionizable salts in the water are converted to their respective acids. Than the water passes through the strong base anion exchange vessel, where the negative radicals of the acids are converted to hydroxyl ( OH- ) ions. The result is a water containing only hydrogen (H+ ) and hydroxyl ( OH- ) ions which combine to form pure water.
The strong acid cation vessel contains resin similar to the strong acid resin used in water softener. However, it is regenerated with an acid to convert the resin to the hydrogen from, where it can readily remove cations such as calcium ( Ca+2 ) magnesium (Mg+2 ) and sodium ( Na+ ) from the water. Hydrochloric (HCI) is used during the regeneration process Exchange capacities range from 15,000 to 30,000grains per cubic foot depending upon the type of cations present in the influent raw water, the effluent water quality desired and the amount/type of acid regenerant used.
The strong base anion vessel contains anion exchange resin. It is regenerated with caustic soda (sodium hydro oxide NaOH) to convert the resin to the hydroxyl from, where it can readily remove anions such as chloride (CI- ), sulphate (SO4-2 ) and nitrate (NO3- ) from the water. The strong base resin (Unlike the weak base resin) is also capable of removing the more weakly ionizable substances such as carbon dioxide (CO2 ) and silica (SiO2 ).
Capacities range from 10,000 to 20,000 grains per cubic foot, depending upon the type of anions present, the quality of water desired and the amount of caustic regenerant used.
Obson DM series demineralizers are economical, efficient and compact units ideally suited for commercial application where heavy duty industrial units (SBTB Series) are not required. These unit produce demineralized water at flow rates from 7 GPM to 45 GPM.
Note: Where removal of silica and carbon dioxide are not required a Weak base Two Bed Demineralizer may be considered. Consult factory of application and design.
The following ions are widely found in raw waters:
           Cations                             Anions

Calcium (Ca2+)                Chloride (Cl-)

Magnesium (Mg2+)           Bicarbonate (HCO3-)

Sodium (Na+)                  Nitrate (NO3-)

Potassium (K+)                Carbonate (CO32-) 

Iron (Fe2+)                     Sulfate (SO42-)

Various feed waters required different treatment techniques to remove these dissolved salts which varies by the no of steps used and kind of resins employed . The followings are the most common type of demineralization  techniques often used to make  good quality deionized water.

 

Strong acid cation + Strong base anion resin systems
These systems consist of two vessels - one containing a cation-exchange resin in the hydrogen (H+) form and the other containing an anion resin in the hydroxyl (OH-) form. Water flows through the cation column, whereupon all the cations are exchanged for hydrogen ions. The decationised water then flows through the anion column. This time, all the negatively charged ions are exchanged for hydroxide ions which then combine with the hydrogen ions to form water (H2O). These systems remove all ions, including silica. In the majority of cases it is advisable to reduce the flux of ions passed to the anion exchanger by installing a CO2 removal unit between the ion exchange vessels. This reduces the CO2 content to a few mg/l and brings about a reduction of the following strong base anion resin volume and in the regeneration reagent requirements. In general the strong acid cation and strong base anion resin system is the simplest arrangement and a deionised water that may be used in a wide variety of applications can be obtained with it. Standard tanks range in size from 14" to 48" in diameter, with flows up to 135 gallons per minute. Obson DM two bed deionizers are a highly efficient means of removing dissolved minerals and solids to produce high purity DI water.

 

Strong acid cation + weak base anion + Strong base anion resin systems
This combination is a variation of the previous one. It provides the same quality of deionised water, while offering economic advantages when treating water which contains high loads of strong anions (chlorides and sulphates). The subtitle shows that the system is equipped with an extra weak base anion exchanger before the final strong base anion exchanger. The optional CO2 removal unit may be installed either after the cation exchanger, or between the two anion exchangers (see picture below). The regeneration of the anion exchangers takes place with caustic soda (NaOH) solution first passing through the strong base resin and then through the weak base resin. This method requires less caustic soda than the method described before because the remaining regeneration solution after the strong base anion exchanger is usually sufficient to regenerate the weak base resin completely. Moreover, when raw water contains a high proportion of organic matter, the weak base resin protects the strong base resin.

Mixed-bed Deionisation
In mixed-bed deionisers the cation-exchange and anion-exchange resins are intimately mixed and contained in a single pressure vessel. The two resins are mixed by agitation with compressed air, so that the hole bed can be regard as an infinite number of anion and cation exchangers in series (mixed bed resin). To carry out regeneration, the two resins are separated hydraulically during the loosening phase. As the anion resin is lighter than the cation resin it rises to the top, while the cation resin falls to the bottom. After the separation step the regeneration is carried out with caustic soda and a strong acid. Any excess regenerant is removed by rinsing each bed separately. The advantages of mixed bed systems are as follows:

•    The water obtained is of very high purity and its quality remains constant throughout the cycle
•    pH is almost neutral
•    Rinse water requirements are very low.

The disadvantages of mixed bed systems are a lower exchange capacity and a more complicated operating procedure because of separation and remixing steps which have to be carried out. Obson mixed bed deionizers provide the ultimate in high purity deionized water, up to 18 megohm/cm. Pre engineered systems with flows up to 190 gallons per minute.
Service DI versus Installed DI Systems
There are two choices when considering using the deionization process in a plant:

•    Service DI (SDI)
•    Installed DI

WATEEN provides our customers any of these working plans convenient to the clients and  his environment.
Service DI
In some instances, a company may want to consider Service Deionization, SDI, for emergency applications, temporary systems or permanent applications requiring Ultrapure Water, with a flow requirement of 1 GPM to 150 GPM. DI exchange tanks eliminate the cost and responsibility of a regenerable DI system and afford you an uninterrupted flow of UltraPure quality water.
Installed DI Systems    
A company should consider an installed DI system if the demand is relatively constant, the water quality is consistent, have the training to handle chemicals and have the permits to discharge waste regenerant chemicals.
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Electrodeionization (EDI)
Electrodeionization EDI Electrodeionization Systems EDI is a water treatment process that removes ionizable species from liquids using electrically active media and an electrical potential to effect ion transport. It differs from other water purification technologies such as conventional ion exchange, in that it is does not require the use of chemicals such as acid and caustic. EDI is commonly used as a polishing process to further deionize Reverse Osmosis (RO) permeate to multi-megohm-cm quality water. Our high-quality deionization modules continually produce ultrapure water up to 18.2MW/cm. EDI may be run continuously or intermittently.    
The continuous electrodeionization (EDI) process, is distinguished from other electrochemical collection/discharge processes such as electrochemical ion exchange (EIX) or capacitive deionization (CapDI), in that EDI performance is determined by the ionic transport properties of the active media, not the ionic capacity of the media. EDI devices typically contain semi-permeable ion-exchange membranes and permanently charged media such as ion-exchange resin. The EDI process is essentially a hybrid of two well-known separation processes - ion exchange deionization and electrodialysis, and is sometimes referred to as filled-cell electrodialysis.
The most convincing advantage of the electro-deionization is the continuous operation. The resins are regenerated through electricity only without any consumption of acids and lye. A further plus for the environment is the low current consumption of this method. Different system combinations are available, according to your demands. We will be happy to advise you perfect solution matching your requirement.


Wateen  design & manufactures its deionization systems using in-house facilities.  Click Here to Contact us for further assistance with your specific water deionizer requirements.
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