- The necessity of water treatment in thermal plan. - The process of water treatment in thermal plant (brief only)

1. Water Treatment For Thermal Plan
Presented To: Doc.HAZIM
Prepared by: sufyan El-Attar
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2. Goal Of This Representation is to
know :
• The necessity of water treatment in thermal
plan.
• The process of water treatment in thermal
plant (brief only)
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8. • But Raw water contain Impurities such as :
• (A) Dissolved Impurities
–(a) Dissolved gases: O2 , CO2 , H2S etc.
–(b) Inorganic salts:
• (i) Cations: Ca++, Mg++, Na+ , K+ , Fe++, Al+++
etc.
• (ii)Anions: CO3 – , Cl– , SO4 – , NO3 – etc.
–(c) Organic salts.
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9. • (B) Suspended Impurities
–(a) Inorganic: Clay and sand.
–(b) Organic: Oil globules, vegetables, and
animal material.
• (C) Colloidal Impurities Finally divided clay
and silica Al(OH)3 , Fe(OH)3 , organic waste
products, coloring matter, amino acids etc.
• (D) Microscopic Matters Bacteria, algae,
fungi etc.
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10. • This what cause a phenomena called
“HARDNESS OF WATER”
• “Hardness in water is that characteristics,
which prevents the lathering of soap”. In other
way we may define it as “soap consuming
capacity of water”.
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11. These impurities may cause:
• Scale and sludge formation
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Sludge cause
scaling for the
boiler

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13. • Corrosion
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Inspecting corrosion inside the boiler

14. Corrosion of heat exchanger
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17. • Priming and foaming
Priming:-Carry over varying amounts of water in
the steam e.g (Foam, mist)
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19. • Caustic embrittlement: weakness of the metal
structure caused by the accumulation of the
corrosive substance.
Brittle: ‫هش‬
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20. So we can all agree that
Water treatment is important af
Reverse Osmosis plant
(R O plant)
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Arrangements for Boiler Feed Water Treatment
Demineralization plant
(D M plant)

21. Demineralization plant (D M plant)
• Demineralization plant employs a chemical
method to separate out the dissolved salt in
raw water.
• The salts which make the water hard are
generally chloride, carbonates, bicarbonates,
silicates & phosphates of sodium, potassium,
iron, calcium and magnesium
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22. Demineralization plant (D M plant)
• In D M plant there are three types of resin
used for boiler feed water treatment process
A- Cation exchange resin.
B- Anion exchange resin.
C- Mixed Bed resin.
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What are Resins

23. Demineralization plant (D M plant)
• Resins are chemical substances (usually
polymers of high molecular weight) used to
react with salts & eliminates them by chemical
process.
• A- Cation Exchange Resin
To removed Na+ but the water has become
acidic.
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24. Demineralization plant (D M plant)
• B- Anion Exchange Resin
This way we have eliminated Cl and thus
acidity of the water. Similar reaction for
H2SO4 also.
C- Mixed Bed Resins
are used in Demineralization plant of boiler feed
water treatment, to remove the ions (especially Na +
and SO3 2 )
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25. • D-Degasser
The function of degasser
tower is to remove
carbonate ions by forming
carbondioxide. In degasser
tower stream of water is
poured from top & air is
blown from bottom to top
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26. Reverse osmosis plant
• reverse osmosis plant employs a simple
physical method to separate the dissolved
salts.
• RO plant uses the process known as reverse
osmosis to produce saltfree water. The
theoretical aspect is described below:
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27. Reverse osmosis plant
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28. Reverse osmosis plant
• Osmosis is a process in which only the solvent
molecules pass through a semipermeable
membrane from higher solvent density to
lower solvent density (i.e. from solution of
lower density to the solution of higher
density).
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29. Reverse osmosis plant
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30. Reverse osmosis plant
• Osmotic pressure: It is the minimum pressure that
should be applied on the higher density solution so that no
osmosis takes place through the semipermeable
membrane is called the osmotic pressure (π).
• π = iCRT
• Where,
• C is concentration of solution,
• R is universal gas constant,
• T is temperature in Kelvin scale,
• i is van’t Hoff’s factor, different solutions. I=1 for infinitely
dilute solution.
• Hence osmotic Pressure is a function of temperature.
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31. Deaerator
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Deaerator is a contact type open heater
in which dissolved oxygen in the feed
water is removed as much as possible by
mechanical means. Gases move from
higher partial pressure to lower partial
pressure. Partial pressure of oxygen in
air is high (as air contains almost 21%
oxygen by volume) than the partial
pressure of dissolved oxygen in feed
water. Hence, by simple mechanical
means it is not possible to eliminate the
dissolved oxygen from water

32. Thank you
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