Group H Presentation (1)

7/30/2019 Group H Presentation (1)

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Che 427 Novel Topics in SeparationProcesses

WATER DEMINERALIZATION

Group HYusuf Alper GL

ise Ezgi AVUOLU

Trker BLROLU


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OUTLINE

INTRODUCTIONo What is demineralization ?

o What methods are used to demineralization water ?

METHODS OF DEMINERALIZATIONo How each process works ?

o Equipments ?

o Advantages and limatations of each method


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INTRODUCTION:

Demineralization of Water Demineralization is the removal of minerals and

nitrate from the water.

There are several different methods of

dimineralization for water and wastewater.

By this process the, It can be possible remove

of hardness as well as remove of all dissolve saltsi.e;.FeCO3,CaCl2


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Demineralization of Water

Why the demineralization of water is necessary ?

The consumption harmful minerals can be avoided by using

demineralizer.

The water can also harm industrial pipes, boilers etc by causingcorrosion, scale building, spotting on finished surfaces, precipitation in

chemical products and other related problems.

The demineralizer is designed to sort out these

problems.


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METHODS OF DEMINERALIZATION

Ion Exchange

Reverse Osmosis

Electrodialysis

Distillation


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Method 1: Ion Exchange

Ion exchange is primarily used for the removal of hardnessions like magnesium and calcium and for waterdemineralization.

The water is pretreated to reduce the suspended solids andtotal dissolved solids load to ion-exchange unit.

The methods used for pretreatment include:

Cold lime without soda ash

Hot lime with or without soda ash

Coagulation and filtration

Filtration Evaporation or distillation

Reverse osmosis

Ultrafiltration


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In this type of process, 90% of Barium

Arsenic

Cadmium

Chromium

Silver

Radium

Nitrites

Selenium

nitrates

can be effectively removed from water.

Better for small systems that need to removeradionuclides.


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Method 1: Ion Exchange Advantages of Ion Exchange1. Ion exchange can be used with fluctuating flow rates.

2. Makes effluent contamination impossible

3. Resins are available in large varieties from suppliers and each resin is

effective in removing specific contaminants.

Limitations of Ion Exchange1. Pretreatment is required for most surface waters

2. Waste is highly concentrated and requires careful disposal

3. Unacceptable high levels of contamination in effluent

4. Units are sensitive to the other ions present.


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Method 2: Reverse Osmosis Water is put under pressure and forced through a

membrane that filters out the minerals and nitrate.

Compact and easy to operate and require minimallabor

Suitable for small systems and for systems wherethere is a high degree of seasonal fluctuation inwater demand.


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Method 2: Reverse Osmosis Reverse osmosis effectively removes nearly all the inorganic

contaminants from water. This process removes over 70% ofthe following:

Arsenic-3 Arsenic-4 Barium Cadmium Chromium-3 Chromium-6 Fluoride Lead

Mercury Nitrite Selenium-4 and selenium-6 Silver


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Method 2: Reverse Osmosis


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Method 2: Reverse Osmosis Advantages of Reverse Osmosis1. Nearly all contaminant ions and most dissolved non-ions

are removed

2. Suitable for small systems with a high degree of

seasonal fluctuation in water demand3. Insensitive to flow and TDA levels

4. Operates immediately without any minimum break-inperiod

5. Possible low effluent concentrations

6. Removes bacteria and particles7. Simplicity and automation operation allows for less

operator attention which makes them suitable for smallsystem applications.


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Method 2: Reverse Osmosis Limitation of RO1. High operating costs and capital

2. Potential problem with managing the wastewater brinesolution

3. Pretreatment at high levels4. Fouling of membranes


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Method 3: Electrodialysis The membranes adjacent to the influent steam are

charged either positively or negatively

Charge attracts counter-ions toward themembrane.

Membranes are designed to allow the positive orthe negative charged ions to pass through themembrane

Ions move from the product water stream through amembrane to the two reject water streams.


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Method 3: Electrodialysis


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Method 4: Distillation


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Demineralization of Water Demineralization is the removal of minerals and

nitrate from water.

There are three methods that are being used; ionexchange, reverse osmosis and electrodialysis.

Each method works in stages but accomplish manyof the same results.

Operational costs and high capital must beconsidered when trying to choose the right system.

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