I tried to explain how DM water can be produced through ultra filtration (UF) and Reverse Osmosis(RO), What parameters should be maintained etc

1. Presented by
Raghab Gorain
Emp No. 104892
Final-Term Appraisal
A Maharatna Company
Date- 08/09/2017NTPC Darlipali
1

2. Coal Storage
Conveyer Belt
Coal
Pulverizer
Furnace
Boiler
Turbine
Condenser
Generator
Transformer
Fly Ash
Chimney
ESP
DM
Plant
PT Plant
Cooling
Tower
Bus Bar
Overview OF Thermal Power Plant
Eco
Bottom
Ash
Raw Water 2

3. DM PlantFeCl3 PE Lime
NaOCL
Acid
NaOH
UFCIP
Tank
Anti scalant Anti oxidant
(SMBS)
Acid
(HCl)
DM Tank-1
(2400m3)
DM Tank-2
(2400m3)
RO Tank
(170 m3)
UF Tank
( 317m3)
RO
RO
MCF
Skid-1
Skid-2
RO Reject
Sludge
267.8m3/hr
7.8m3/hr
260m3/hr
Backwash Filter
UF
180m3/hr
Sand Filter
Sump
Basket Strainer
HP Pump
71m3/hr
(2W+1S)
61m3/hr
(2W+1S)
120m3/hr
(2W+1S)
Degasser Tower
Clarifier
Aerator
Reservoir
MB
RO Per. Tfr.
Pump
A
B
C
Cl2
3

4. Pretreatment of water
Impurities present in Raw water
 Suspended
impurities
 Ionic solids
 Micro-organisms
 Dissolved Gasses
Treatment of water in PT plant
Mainly four steps are used to remove the impurities in raw water
 Oxygenation- Aeration of the water to precipitate out the ferric salt. Here ferrous salts are converted to
ferric salt and also it removes the dissolved CO2
 Coagulation-In this process a flux mixture is produced by the addition of FeCl3 and polyelectrolyte.
 Flocculation & Settlement-It is the process to precipitate out the solids from the clarifier.
 Filtration- To remove the impurities
Aeration of water Water Reservoir
4

5. Pretreatment of Water
Exposing the raw water to atmospheric air. So
some of the dissolved salts oxidized, specially
ferrous and manganous bicarbonate as follows
4Fe(HCO3)2 + O2 + 2H2O =4Fe(OH)3 + 8CO2
2Mn(HCO3)2 + O2 = 2MnO2 + 4CO2 + 2H2O
Aeration
Clarification
FeCl3, PAC :used as flocculating agent
Lime : To maintain pH
Cl2: As disinfectant
Schulze-Hardy rule
Greater the valency of the flocculating ion,
greater will be its coagulation power.
Fe3+ ion is 1000 times more effective than that of
monovalent ion. So FeCl3 is used in clarifier.
Fe3+ + PO4
3- = FePO4
Cl2 +H2O = HOCl + HCl
Gravity Sand Filter(GSF)
It is used to remove the suspended particles
and the microbial organisms from the clarified
water.
Filtered water turbidity: <5 NTU
Residual Cl2: 0.2-0.5 ppm
GSF
5

6. Ultra-Filtration(UF) System
UF(Filtered water supply Pumps)
Required Flow 180 m3/hr
Pump 3(2W+1S)
(Each 90 m3/hr)
Basket Strainer
No. of stream 2(Both Working)
Flow per stream(m3/hr) 90
Material of
Construction
SS316
Size 100 m
UF Membrane
Make Hyflux
Material of construction Polyether sulphone
Water flow type Out to in
Permeate Flow per stream(m3/hr) 80
% of Recovery 95
No of skid 2
Total membrane per skid 25
UF Backwash Pump
No of pumps 2(1w+1s)
Required Flow per
membrane(m3/hr)
6
Total no of membrane per Skid 25
Required backwash flow(m3/hr) 150
6

7. Parameters Value
pH 6.5 -7.5
Temperature( oC) 20-35
TSS(ppm) <4
Turbidity(NTU) <4
COD BDL
BOD BDL
Fe & Mn <0.3 and
Nill
Oil and Grease Nill
UF Inlet parameters
UF Module
UF CIP Tank
UF Tank
Basket Strainer
Air Compressor
UF Backwash PumpBackwash Waste
CIP waste
UF Feed Sump
UF Outlet parameters
Parameters Value
SDI <3
Turbidity <0.2 NTU
Ultra-Filtration(UF) System
150m3/hr
(1W+1S)
7

8. Cleaning of UF membrane
NaOH NaOCl HCl
No of Tank 2W 2W 2W
Capacity(m3) 0.5 0.5 0.5
Cleaning pump flow(m3/hr) 100 100 100
Dosage(ppm) 150 400 300
Required quantity as
available(kg/hr)
104.17 500 166.67
Sp. Gravity @25 oC 1.45 1.15 1.18
Concentration of fluid(w/w) 48% 10% 30%
Solution feed flow(LPH) 71.84 434.78 141.24
Dosing time(Min.) 10 10 10
No of pumps used 2(1w+1s) 2(1w+1s) 2(1w+1s)
Provided Pump
capacity(LPH)
100 500 200
Chemical Dosing in UF
8

9. Cleaning of UF membrane
Maintenance cleaning is a semi automated sequence meant short-term regaining of permeability.MC involves a short duration (60 min.)
cleaning with chlorine and HCl. MC should be conducted one in every 72 hrs.
Maintenance Cleaning(MC)
Cleaning Chemicals and their concentrations
NaOH & NaOCl
NaOCl 400 ppm (Free chlorine should be 200 ppm)
NaOH 11 pH(150ppm)
MC1 MC2
HCl
HCl 2.5 pH
(300ppm)
Recovery Cleaning (RC)
High pH NaOCl 400 ppm + NaOH 11 pH (150 ppm)
Low pH 2.5 pH (300ppm)
Cleaning Frequency
UF Running hrs 71 72 144 216 288 360 432 504 576
Cleaning Service MC1 MC1 MC1 MC2 MC1 MC1 RC MC1
After 6 MC 1 recovery cleaning will be done
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10. UF System
UF Permeate water storage Tank
No. of Tank 1
Available
Capacity(m3)
317
Effective volume
per meter
height(m3)
52.83
UF Air Blower Pump
No. of Blowers 2(1w+1s)
Available
Capacity(Nm3/hr)
71
Type of Blower Twine Lobe
UF CIP Tank
Provided
capacity(m3)
3
UF CIP Pump
No. of pump 2(1w+1s)
Provided flow per
each pump(m3/hr)
100
UF Permeate transfer pump
No. of pump 3(2w+1s)
Flow through each
pump(m3/hr)
71
10

11. Reverse Osmosis(RO)
Micron Cartridge Filter(MCF)
RO Inlet MCF RO CIP MCF
Make Parker Hannifin
(USA)
No. 3(2w+1s) 1(w)
Material of filter
media
Polypropylene Polypropylene
Design flow
rate(m3/hr)
71 64
Max. allowable
press. Drop(KSC)
0.5 0.5
Efficiency 90%
Size(Nominal) 5 m 5m
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12. RO High Pressure Pump
No. 3(2w+1s)
Flow through each Pump
(m3/hr)
71
Chemical Dosing in RO
Acid Antiscalant Antioxidant
No of Tank 2 2 2
Capacity(m3) 1.7 0.2 0.1
RO Feed flow(m3/hr) 142 142 142
Dosage(ppm) 25 5 5
Required quantity as
available(kg/hr)
71 14.2 7.1
Sp. Gravity @25 oC 1.07 1.05 1.1
Concentration of fluid(w/w) 5% 5% 10%
Solution feed flow(LPH) 67 14 7
Dosing time(Min.) 10 10 10
No of pumps used 2(1w+1s) 2(1(w+1s) 2(1w+1s)
Provided Pump capacity(LPH) 100 20 10
Cleaning of RO membrane
12

13. RO Dosing Chemicals And Their Functions
Hydrochloric Acid (HCl):
It maintains the pH of the RO inlet water. It decreases the pH
Antioxidant:
Sodium meta bisulphite(SMBS) is used as anti oxidant. In the RO feed water if any oxidizing agent (like Cl, ozone etc) will
be present then it will damage the RO membranes. Under alkaline pH conditions, chlorine attack is faster than at neutral or
acidic pH and it will catalyze the membrane degradation. So antioxidant SMBS is used to remove the free Cl and as a
biostatic.
When Na2S2O5 is dissolved in water then it will form sodium bisulphite(SBS)
Na2S2O5 + H2O = 2NaHSO3
Free chlorine forms HOCl in water. Cl2 + H2O = HOCl + HCl
HOCl oxidize the RO membrane, so we have to remove this one and NaHSO3 reduces the HOCl.
2NaHSO3 + 2HOCl → H2SO4 + 2HCl + Na2SO4
Antiscalant:
In the RO feed water carbonate, phosphate and sulphate salt of Ca, Mg etc. are present that will form scale in the RO
membrane. So we have to remove these. Anti scaling agent is used to remove these salts.
13

14. RO System
RO Permeate water storage Tank
No. of Tank 1
Available Capacity(m3) 137 out of
170
Effective volume per meter
height(m3)
28.33
RO Air Blower Pump
No. of Blowers 2(1w+1s)
Available Capacity(Nm3/hr) 2460
Type of Blower Centrifugal Blower
RO CIP Tank
Provided capacity(m3) 3.6
RO CIP Pump
No. of pump 2(1w+1s)
Provided flow per each pump(m3/hr) 115
RO Permeate transfer pump
No. of pump 3(2w+1s)
Flow through each pump(m3/hr) 61
Degasser Tower
No. of DG Tower 2(1w+1s)
Design Flow(m3/hr) 123
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15. Particle Rejection and Passage by MF, UF, RO
Micro-Filter
Size of Removable particle(mm) 0.1-0.4
Removed particle Bacteria,Flocculted material,
TSS
Passage materials Macromolecules, dissolved
solids
Ultra-Filtration(UF)
Size of Removable particle(mm) 0.1-0.01
Removed particle Colloid particles, protein,
microbiological molecules,
Large organic molecules
Passage materials Surfactants, dissolve solids,
smaller molecules, acids &
alkaline compounds
Trans-membrane Pressure(bar) 1-7
Reverse Osmosis(RO)
Size of Removable
particle(mm)
0.0001-0.001
Removed particle Removed 99% dissolved
materials,(95-97)% dissolved
organics, 98% colloidal and
biological matters
Passage materials Few ions smaller than water
molecule, like Na+, Ca2+, Ag+
etc can pass.
Salt passage increases in RO system by
 Effective pressure decrease
 Temperature increase
 Feed salt concentration increase
 Permeate flow decrease
15

16. RO membrane
RO Membrane
Make Torrey
Material of construction Polyamide, Spiral wound
Water flow type Out to in
RO Feed Flow per stream 70.8 m3/hr
% of Recovery 87
RO Permeate Flow per
stream
61.6
Array of per RO train 8:4:2
Total membrane per skid 25
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17. Reverse Osmosis
Reverse osmosis is separation method where ions, molecules are removed by applying pressure against the osmotic pressure.
Here water is passed from low concentrated to high concentrated solution through a semi permeable membrane against the
osmotic pressure.
RO Membrane
RO Permeate
RO Reject
Salt Rejection:
Salt Rejection %
= Conductivity of (Feed-Permeate)*100
Conductivity of feed
Recovery:
Recovery%
= Permeate flow rate *100
Feed flow rate
RO Membrane
RO PermeateRO Reject
Concentration Factor
Recovery%
= 1
(1-% Recovery)
Feed
Feed
Reject RO Membrane
Reject
Reject
RO Membrane
Single Stage
Double Stage 17

18. Mixed Bed(MB)
Mixed Bed
No. of Unit 3(2w+1s)
Available Capacity(m3/hr)
per unit
60
Size of the strainer 1500mm*2300mm
(Dia*Height)
Alkali Measuring Tank
No. of Tank 3(2w+1s)
Provided volume 0.17 m3 (165 Lt.)
Req. vol. per regeneration 162 Lt.
Acid Measuring Tank
No. of Tank 1
Provided volume 0.15 m3 (150 Lt.)
Req. vol. per regeneration 145 Lt.
MB Air Blower Pump
No. of Blowers 2(1w+1s)
Available
Capacity(Nm3/hr)
210
Type of Blower Twine Lobe
DM water storage Tank
No. of Tank 2
Available Capacity(m3) 2400
Effective volume per meter
height(m3)
200
DM Water Make UP Pump
No. of Blowers 2(1w+1s)
Available
Capacity(Nm3/hr)
100
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19. MB Resin
Cation Exchange Resin Anion Exchange Resin
Manufacturer Auchtel Auchtel
Required quantity(m3/MB) 0.873 1.051
Material of Construction Styrene-divinyle benzene
copolymer
Styrene-divinyle benzene
copolymer
Functional Group Sulphonate(-SO3
-) -[N(CH3)]3
+
Total Exchange Capasity 2 Eq./L 1.3 Eq./L
Packing Density(g/L) 800-840 700
Particle Size(mm) 0.3-1.2 0.3-1.2
Chemical stability Insoluble in dilute acids and bases Insoluble in dilute acids
and bases
Max. Temperature(oC) 120 60
Min. bed depth(mm) 500 500
Service flow rate(BV/L) 5-40 5-40
Slow Rinse(BV/L) 2 2
Fast Rinse(BV/L) Same as service flow rate Same as service flow rate
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20. Cation Exchange Resin
Cation Exchange Resin
Chemicals HCL H2SO4 NaCl
Level(g/L) 30-150 40-240 50-250
Flow Rate(BV/hr) 2-5 2-10 2-8
Concentration(%) 5-8 0.7-6 8-12
Min. contact time 30 min
2R-H + Na2CO3 2R-Na+H2CO3
Reaction mechanism of Cation exchange Resin
During service condition
During Regeneration condition R-Na + HCl  R-H + NaCl
R=
20

21. Anion Exchange Resin
Reaction mechanism of Anion exchange Resin
2R’-OH + H2SO4 R’2SO4+2H2ODuring service condition
During Regeneration condition R’2SO4 + NaOH2R’-OH + Na2SO4
Anion Exchange Resin
Chemicals NaOH
Level(g/L) 30-150
Flow Rate(BV/hr) 3-5
Concentration(%) 5-8
Min. contact time 30 min
R’=
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22. DM water production Data Plot(Weekly)
DM Water Production Data
6/17/2017 1 0 6/17/2017 1
6/24/2017 4.9 0 6/24/2017 4.9
6/30/2017 5.4 0 6/30/2017 5.4
7/6/2017 5.40 0.00 7/6/2017 5.40
7/13/2017 8.709 0 7/13/2017 8.709
7/20/2017 10.285 0 7/20/2017 10.285
7/27/2017 10.549 0 7/27/2017 10.549
8/2/2017 11.3 1.6 8/2/2017 11.3
8/10/2017 11.3 3.7 8/10/2017 11.3
8/17/2017 6.7 6.1 8/17/2017 6.7
8/23/2017 1.654 7.484 8/23/2017 1.654
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23. Images of Darlipali Project
DM Tank
Chemical Building
GSF Chimney
CPU Boiler ESP Generator
DM Control room screen
RO skid
Water Reservoir
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24. Acknowledgement
 Sh. S Ghosh Sir(GM, O&M)
 Sh. A V S Rao(GM, Operation & Commissioning)
 Sh. S K Mohanty Sir (AGM, O&M- Chemistry)
 Seniors of My Department
 NTPC Darlipali
 NTPC
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