Power Plant Chemistry
Transcript of Power Plant Chemistry
Water Water ChemistryChemistry
T.P.S., Parli-V. Certified for ISO 9001-2000ISO 14001-2004
Presentation by
H. B. Zade. Sr. Chemist
Mother EarthMother Earth
The Greatest Chemist in the The Greatest Chemist in the UniverseUniverse
Water RouteWater Route
R/W Pump House
U-3,4,5 P. T. Plant
U-3,4 DM Plant
U-3,4,5 Soft.Plant
TPS,Colony DomesticMakeup To All Units
Makeup To All UnitsWith interconnection facility
Use Of ChemicalsUse Of Chemicals Pretreatment Plant
1. Alum: FeSO4 Al2(SO4)3.18 H2O
2. Poly Aluminum Chloride3. Bleaching powder : Ca(OCl)2
4. Hydrated Lime : Ca(OH)2
Softening Plant1. Common Salt : NaCl
Demineralization Plant
1. Hydrochloric Acid : HCl
2. Caustic Soda Lye : NaOH
3. Hydrated Lime : Ca(OH)2
Boiler Drum WaterBoiler Drum WaterTrisodium Ortho Phosphate: Na3PO4.12H2O
Na3PO4+H2O NaOH +Na2HPO4 (Maintains PH)
2Na3PO4+3CaSO4 Ca3(PO4)2+3Na2SO4
10Ca+6PO4+2OH 3Ca3(PO4).Ca(OH) 2 .
Calcium Hydroxy apetite
3Mg+2SiO3+2OH+H2O 3MgO.2SiO2.2H2O
Serpentine
Above soft sludges can be removed by CBD Operations
Feed Water Dosing1 Hydrazine hydrate: N2H4.H2O
N2H4 +O2 N2+H2O (Oxygen scavenger)
3N2H4 4NH3 + N2 (at temp. > 205 °c)
(Res.N2H4 at Eco. Inlet = 0.01 to 0.02 ppm)
2 Liq. Ammonia : NH4OH ( Maintains PH)
Condensate Dosing : Only N2H4.H2O At C E P Discharge as it passivates theCopper alloy component of LP heater coils & Acts also as Oxygen scavenger
Cond.tube leakage (What happens ? )
1: Cooling water mixes in condensate water2:Hardness salts get carried to boiler& deposit
in boiler tubes3:Increased concentration of DO causes pitting
corrosion in boiler tubes, corrosion in preboiler i.e..cond.,feed water heaters,de areator depositing corrosion products in high heat zones resulting BTL
4:Salts like MgCl2 causes Hydrogen Embrittlement resulting BTL
Cond.tube leakage (Indications) 1:Increases cation conductivity of
condensate (Limit 0.3 micromhos/cm) 2:Increases Na Con. of condensate (Limit 10 ppb) 3:Increases Blr Drum water parameters
like PH, Cond.,Silica, Alkalinity
Remedial Action To arrest CTL by adding saw dust(in case
it is minor) Withdrawal of Unit for attending CTL in
case Conden. Parameters exceed permissible limits
Limits; Sodium(Na) at CEP outlet: 10 ppb or Cation conductivity of condensate: 0.3 Micro mhos/cm
ETP IETP I
References:
CEGB Vol.V BHEL (Trichi) Text book of water chemistry by Linus Pauling (California) Personal experience
Thanking you all