◆ Design Feature of Demineralization System
The configuration of demineralization system is shown on the next pages depending on the design conditions.
◆ Ion Exchange Techniques
Demineralizing by ion exchange is the process of removing dissolved minerals from water by using ion exchange resins. Several techniques have been developed for the application of the ion exchange
unit.
 Cocurrent system
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Downflow service, Downflow regeneration |
Countercurrent system |
Downflow service, Upflow regeneration |
Air or Water holddown system |
Packed bed system : Upcore system |
(Downflow service upflow regeneration) |
Amberpack system, Fluidized bed system |
(Upflow service downflow regeneration) |
Co-countercurrent system |
Down flow service, Down flow and Up flow regeneration |
◆ Vacuum Degasifier
The vacuum degasifier removes dissolved gases-carbon dioxide and oxygen-from the treated water by using vacuum.
◆ Demineralizer Arrangements
There are many different arrangements of ion exchange equipment which can achieve similar effluent results. Many factors effect the selection of the exchange equipment and its arrangement. Some of the more important factors are
Upon receipt of a water sample or analysis, HaJI studies the various ion exchange arrangements available and establishes the optimum system to meet our customer's overall requirements. Illustrated below are some typical arrangements of ion exchange systems with a brief explanation of their applications.
 SC -Strong acid cation exchanger
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WC -Weak acid cation exchanger |
SB -Strong base anion exchanger |
WB -Weak base anion exchanger |
MB -Mixed bed exchanger |
DG -Degasifier |
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Low alkalinity water, with low effluent silica levels required. This arrangement can yield neutral waste requiring minimum addition of chemicals. |
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High alkalinity water, with low effluent silica levels required.
This arrangement has a higher installation cost but lower running cost than arrangement(1) .Where oxygen removal is required, the vacuum degasifier will be used. |
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Same as arrangement (1) except no silica removal capacity It is very efficient in operating the system at low cost and
very effiective in removal of the strong acids. |
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Same as arrangement (2) except no silica removal capacity Weak base anion resins are very efficient having low operating cost. |
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Low alkalinity plus high chloride and sulfate water requiring low silica effluent levels.
This arrangement is has efficiency on the anion side since the weak base resins will be regenerated in series utilizing the waste caustic from the strong base unit. |
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High alkalinity plus high chloride and sulfate water requiring low silica effluent levels.
This arrangement has the same anion efficiency as arrangement (5). |
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High alkalinity, high hardness, high chloride and sulfate water with silica removal required.
This arrangement has more excellent capacity than others. |
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Mixed bed is capable of producing the hish purity demineralized water with a small range of flow. |
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System greatly improves efficiency of mixed bed when influent contains high percentage of alkalinity. |
(System 1,2,3,4,5,6 or 7with MB as a polisher) |
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Mixed bed polisher is frequently added to systems 1 through 7 where extremely low effluent solids are desired. This permits high chemical efficiency of the primary demineralizers plus extreme purity of mixed bed polisher. |
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