Sunday, May 1, 2011

What is De Ionization?



Water Deionizers

PakWater Care Services is a leading provider of deionization solutions. Our water deionizers are rugged, Pre-egineered, Pre-assembled, standardized units that minimize expensive installation and start-up costs. We have designed our Deionization systems to maximize the efficiency and repeatability of the unit during the service and regeneration modes.


The Process of Deionization or Ion-Exchange
In the context of water purification, ion-exchange is a rapid and reversible process in which impurity ions present in the water are replaced by ions released by an ion-exchange resin. The impurity ions are taken up by the resin, which must be periodically regenerated to restore it to the original ionic form. (An ion is an atom or group of atoms with an electric charge. Positively-charged ions are called cations and are usually metals; negatively-charged ions are called anions and are usually non-metals).

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-)
Ion Exchange Resins


There are two basic types of resin - cation-exchange and anion-exchange resins. Cation exchange resins will release Hydrogen (H+) ions or other positively charged ions in exchange for impurity cations present in the water. Anion exchange resins will release hydroxyl (OH-) ions or other negatively charged ions in exchange for impurity anions present in the water.


The Application of Ion-Exchange to Water Treatment and Purification


There are three ways in which ion-exchange technology can be used in water treatment and purification: first, cation-exchange resins alone can be employed to soften water by base exchange; secondly, anion-exchange resins alone can be used for organic scavenging or nitrate removal; and thirdly, combinations of cation-exchange and anion-exchange resins can be used to remove virtually all the ionic impurities present in the feedwater, a process known as deionization. Water deionizers purification process results in water of exceptionally high quality.


Deionization


For many laboratory and industrial applications, high-purity water which is essentially free from ionic contaminants is required. Water of this quality can be produced by deionization.The two most common types of deionization are:



  • Dual-bed Deionization
  • Mixed-bed Deionization
Two-bed deionization


The Dual-Bed Deionizer consists 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.To keep the water electrically balanced, for every monovalent cation, e.g. Na+, one hydrogen ion is exchanged and for every divalent cation, e.g. Ca2+, or Mg2+, two hydrogen ions are exchanged. The same principle applies when considering anion-exchange. 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).


Mixed-Bed Deionization

In mixed-bed deionizers the cation-exchange and anion-exchange resins are intimately mixed and contained in a single pressure vessel. The thorough mixture of cation-exchangers and anion-exchangers in a single column makes a mixed-bed deionizer equivalent to a lengthy series of two-bed plants. As a result, the water quality obtained from a mixed-bed deionizer is appreciably higher than that produced by a two-bed plant.


Although more efficient in purifying the incoming feedwater, mixed-bed plants are more sensitive to impurities in the water supply and involve a more complicated regeneration process. Mixed-bed deionizers are normally used to ‘polish’ the water to higher levels of purity after it has been initially treated by either a two-bed deionizer or a reverse osmosis unit.

Dual Bed Demineraliser


DE-MINERALISER, principle is ion exchange i.e. two bed demineraliser ,CATION & ANION Exchanger.

CATION EXCHANGER
IS Strong acid cation resin H+ form filled in the rubber lined vessle to save the vessle From acid. Cation resin is charged by using HCl 10 % commercial for to exchange positive ion i.e. Na, Ca, Mg with positive ion H+. During service the same H+ ion will exchange with Na+, Ca+ & Mg+ ion.

ANION EXCHANGER
IS Strong base anion resin OH- form ,filled in the rubber lined vessel to save the vessel From Caustic soda.

Anion resin is charged by using NaOH 10 % commercial for to exchange negative ion i.e. Cl,So4,Alkalinity, etc… with Negative ion OH-. During service the same OH- ion will exchange with Cl-, So4- & Alkalinity etc…

Typical Ion Exchange Process in Cation & Anion Exchanger.

CATION EXCHANGER

Cation resin + H2O + HCl = H cation resin + HCl + Positive ion + H2O
H Cation resin + H2O + positive & negative ion = positive ion cation resin + H2O + H negative ion H2O + H negative ion from cation exchanger.


Anion resin + H2O + NaOH = OH Anion resin + 2NaOH
OH Anion resin + H2O + H negative ion = Negative ion anion resin + 2H2O
Negative ion anion resin + 2H2O So finally we got Mineral free water (Demineralise water)

Mix Bed (Polisher)

Mix bed de ioniser is used as polishing treatment of demineralise water to get fine deionise water.

Here both the resin CATION & ANION is filled in the vessel & charged by HCl as well as NaOH.

There is difference in density of CATION & ANION RESIN SO by giving water back force we are Separating Both the resin & charged by same process as demineraliser.

Charged CATION & ANION RESIN will be mix by giving compressed air in the vessel.

Finally we pass the demineralise water from the mix bed vessel to get fine ion free water.
Pakwater Care Services design the Demineraliser & Mix bed deioniser to get maximum efficiency from the system ,With easy operation in single valve, Atomization, Manual Multiple valve.

The material of construction of the system may be Mild Steel/ FRP,
Mild steel in side rubber lined, Stainless steel rubber lined, PVC etc…as suit to your requirement.

[caption id="attachment_1576" align="alignnone" width="498" caption="Mix Bed De Ioniser"]

Weak base ANION exchanger.

It is used for weak anions from the decationic water. Week base anion resin will charged by NaOH.

By using of weak base anion resin you can remove 90 % of total Cl & SO4 from the de cationic water.

Here we can charge this resin by effluent of strong base anion resin, So we can save the quantity of NaOH.

This system is used to save operation cost in D.M. unit as well as in partial D.M.
water plant. Sometime by giving this system we can use it as pre-treatment of anion exchanger.

Week acid CATION exchanger .

It is used for weak captions from the water. Weak Acid cation resin will charged by HCl.

By using of weak acid cation resin we can remove 90 % of total Ca & Mg from water.

Here we can charge this resin by effluent of strong acid cation resin, So we can save the quantity of HCl.

This system is used to save operation cost in D.M. unit as well as in partial D.M.
Water plant. Sometime by giving this system we can use it as pre treatment of cation exchanger. It can work as Dealkaliser, to remove alkali from water.

PakWater Care Services design Weak base Deioniser to get maximum system, With easy operation in single valve, manual valves.

The material of construction of the system may be FRP Mild steel in side rubber lined, Stainless steel rubber lined, PVC etc. as suit to our requirement.

FEATURES

  • Gives us Chemically Pure Water.
  • Due to ion exchange process resin is chargeable gives us continue operation.
  • Low charging cost.
  • Durable as it is made of acid & alkali resistant, rubber lined vessel.
  • Continue watch of quality of treated water fitted with conductivity analyser.
  • Due to compact models can installed in very small area.
  • Easy installation.
  • Wide range models as per quality of raw water & quantity of treated water.
  • Auto and manual operational ranges.

AREA OF APPLICATION

  • DEIONISE WATER.
  • BATTERY WATER.
  • BOILER FEED WATER.
  • PHARMACEUTICALS.
  • LABORATORIES.
  • CHEMICAL INDUSTRIES.
  • TEXTILE INDUSTRIES.
  • SODA & SOFT DRINK MANUFACTURING UNIT.
  • ELECTRONIC INDUSTRIES.
DE-MINERALISER, principle is ion exchange i.e. two bed demineraliser ,CATION & ANION Exchanger.

CATION EXCHANGER
IS Strong acid cation resin H+ form filled in the rubber lined vessle to save the vessle From acid. Cation resin is charged by using HCl 10 % commercial for to exchange positive ion i.e. Na, Ca, Mg with positive ion H+. During service the same H+ ion will exchange with Na+, Ca+ & Mg+ ion

ANION EXCHANGER
IS Strong base anion resin OH- form ,filled in the rubber lined vessel to save the vessel From Caustic soda.

Anion resin is charged by using NaOH 10 %

commercial for to exchange negative ion i.e. Cl,So4,Alkalinity, etc… with Negative ion OH-. During service the same OH- ion will exchange with Cl-, So4- & Alkalinity etc…Typical Ion Exchange Process in Cation & Anion Exchanger.

CATION EXCHANGER

Cation resin + H2O + HCl = H cation resin + HCl + Positive ion + H2O
H Cation resin + H2O + positive & negative ion = positive ion cation resin + H2O + H negative ion H2O + H negative ion from cation exchanger.


Anion resin + H2O + NaOH = OH Anion resin + 2NaOH
OH Anion resin + H2O + H negative ion = Negative ion anion resin + 2H2O
Negative ion anion resin + 2H2O So finally we got Mineral free water (Demineralise water)


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