boiler water chemistry · 2014. 8. 23. · ntpc’s growth journey 11333 20249 41794* 1975 ntpc...
TRANSCRIPT
Nov 21, 2013 1
Boiler Water Chemistry
Best Practices - A key to success in Super Critical Boilers
By: Team NTPC
Nov 21, 2013 2
NTPC Overview
OT – Introduction
Oxygen Dosing System Details
Operation and Control
AVT v/s OT – Data Comparison
AVT v/s OT - Benefits
Results and Conclusion
PRESENTATION OUTLINE
Nov 21, 2013 3
Our Vision
““To be the worldTo be the world’’s s largest and best largest and best power producer, power producer, powering Indiapowering India’’s s
growthgrowth””
Nov 21, 2013 4
Today ~41 GW*
Coal Gas Nuclear Hydro Renewables
2032~ 128 GW
Planning for Accelerated Growth
Capacity under construction: ~20 GW
* 10 MW Solar PV Projects
Nov 21, 2013 5
NTPC’s Growth Journey
1133320249
41794*
1975
NTPC incorporated
1997
Became a NavratnaCompany
2004
Listed on Indian Stock Exchanges(GoI holding
89.5%)
2010
• Became a MaharatnaCompany
• GOI divested 5% equity
1982
First 200 MW unit
commissioned
2013
• GOI further divested 9.5% equity
*10 MW Solar PV
Nov 21, 2013 6
Note: Capacity includes capacity under construction; Map not to scale
RIHAND(3,000 MW)RIHAND(3,000 MW)SINGRAULI
(2,000 MW)SINGRAULI(2,000 MW)
FARIDABAD(430 MW)FARIDABAD(430 MW)
DADRI(817 MW)DADRI(817 MW)
NCTPP(1,820 MW)NCTPP(2,310 MW)
ANTA(413 MW)ANTA(413 MW)
AURAIYA(652 MW)AURAIYA(652 MW)
UNCHAHAR(1,050 MW)UNCHAHAR(1,050 MW)
TANDA(440 MW)TANDA(440 MW)
KAHALGAON(2,340 MW)KAHALGAON(2,340 MW)
FARAKKA(2,100 MW)FARAKKA(2,100 MW)
KORBA(2,600 MW)KORBA(2,600 MW)
VINDHYACHAL(4,260 MW)VINDHYACHAL(4,260 MW)GANDHAR
(648 MW)GANDHAR(648 MW)
KAWAS(645 MW)KAWAS(645 MW) TALCHER KANIHA
(3,000 MW)TALCHER KANIHA
(3,000 MW)
RAMAGUNDAM(2,600 MW)RAMAGUNDAM(2,600 MW)
SIMHADRI(2,000 MW)SIMHADRI(2,000 MW)
KAYAMKULAM(350 MW)KAYAMKULAM(350 MW)
TALCHER Thermal(460 MW)TALCHER Thermal
(460 MW)
KOLDAM(800 MW)KOLDAM(800 MW)
TAPOVAN VISHNUGAD(520 MW)TAPOVAN VISHNUGAD
(520 MW)
LOHARINAG PALA(600 MW)LOHARINAG PALA
(600 MW)
SIPAT2,980 MWSIPAT2,980 MW
BARH3,300 MWBARH3,300 MW
BTPS(705 MW)BTPS(705 MW)
BONGAIGAON(750 MW)BONGAIGAON(750 MW)
VALLUR(1,500 MW)VALLUR(1,500 MW)
MAUDA(1,000 MW)MAUDA(1,000 MW)
RGPPL(1480 MW)
RGPPL(1480 MW)
IGSTPP(1,500 MW)IGSTPP(1,500 MW)
DURGAPUR(120 MW)DURGAPUR(120 MW)
BHILAI574 MWBHILAI574 MW
ROURKELA(120 MW)ROURKELA(120 MW)
NABINAGAR(1,000 MW)NABINAGAR(1,000 MW)
GAS POWER STATIONS
COAL POWER STATIONONGOING HYDRO POWER PROJECTS
ONGOING THERMAL PROJECTS
Pan India Presence
No. of plants
Capacity MW Share
NTPC OwnedCoal 16 32,355 77.42%
Gas/Liquid fuel 7 3955 9.46%Solar 2 10 0.02 %
Sub-Total 25 36,320 86.9%Owned by JVs
Coal 6 3534 8.46%Gas 1 1940 4.64%
Sub-Total 7 5474 13.1%Total 32 41,794 100%
Nov 21, 2013 7
Implementing high efficiency technology
Sustainable Power Development
Hydro, Renewable & Nuclear Energy forays
1499 MW hydro capacity under construction Developing Wind and Solar capacities – 1000 MW by 2017 Anushakti Vidhyut Nigam Ltd. - JV company formed with NPCIL for nuclear
power development - NTPC(49% ) & NPCIL( 51%) – 14 GW by 20
Nov 21, 2013 8
Investment of more than 1% of PAT for R&D Activities and Climate Change studies
ECBC (Energy Conservation Building Code) compliant building
ISO/NABL 17025 Certified Labs, CBB certification
Research & Technology Development
Focus Areas
Efficiency & Availability Improvement and Cost Reduction
Renewables and Alternate Energy
Climate Change and Environment
Scientific Support to Stations
Nov 21, 2013 9
Oxygenated treatment – Feed water treatment or conditioning.
Injection of High purity oxygen gas at CPU & Deaerator outlet
Conversion of Fe3O4 (Magnetite) to hydrated FeOOHand Fe2O3 (Hematite).
Hydrated FeOOH and/or Fe2O3 block the pores in the magnetite layer and forms a more adherent protective layer and reduces the migration of iron
Prevents flow accelerated corrosion (FAC).
OXYGENATED TREATMENT (OT)
Nov 21, 2013 10
FEED WATER SPECIFICATION
S.N Parameter Units
Normal OperationDuringStart upAlkaline
water Treatment
Oxygenated Treatment
1 pH Min 9.0 8-8.5 Min 9.0
2 ACC, ms/cm ms/cm Max 0.2 <0.15 Max 0.5
3 D O ppb < 5 30-150 Max 100
4 Iron ppb < 2 < 2 < 20
5 Sodium ppb < 2 < 2 < 10
6 Silica ppb <10 < 10 < 30
7 Turbidity NTU <2 < 2 <5
Nov 21, 2013 11
STEAM PARAMETERS LIMITS
Parameter NormalAction 1 (2 weeks per year)
Action 2(2 days per
year)
Action 3(8 hours per year)
Immediate shut down
ACC, ms/cm<0.15 >0.2 >0.3 >0.6 >2
Silica, ppb 10 >10 >30 >40 >50
Sodium, ppb <3 >3 >6 >12 >24
Chloride, ppb <3 >3 >6 >12 >24
Nov 21, 2013 12
STEAM WATER ANALYSIS SYSTEM (SWAS)
Online Monitors:
S.No System Type of measurement1 Make up DM water SP.COND., CATION
CONDUCTIVITY (ACC)
2 CEP discharge pH, ACC, Na, DO, SP.COND.,
3 CPU Outlet pH, ACC, Na, SILICA, SP.COND.,
4 Deaerator outlet DO
5 Feed water at economizer inlet
pH, ACC, COND., SILICA
Nov 21, 2013 13
STEAM WATER ANALYSIS SYSTEM (SWAS) contd….
S.No System Type of measurement6 Separator outlet steam ACC, SP.COND., SILICA
7 Main steam pH, ACC, Na, SILICA, SP.COND.,
8 Water separation storage tank of boiler
Cation conductivity (ACC)
9 Reheated steam Cation conductivity (ACC)
Nov 21, 2013 14
STARTUP, OPERATION AND SHUTDOWN
Stop oxygen feed at least one hour before shutdown
Increase ammonia feed rate to achieve a pH > 9.0
Open Deaerator vents
Nov 21, 2013 15
Normal Running condition
During shut downAmmonia vaporise to upper layer
During shut downDissolution of iron in low pH water
Crud load during start up
Water wall tube deposits from feed iron transport
CRUD LOAD DURING START UP
Nov 21, 2013 16
BOILER PROTECTIVE LAYER
Migration of Fe2+ to fluid boundary layer FeOOH/Fe2O3 block pores lowering Fe2+ migration
AVT OT
Nov 21, 2013 17
The piping material is of SS 316
OXYGEN DOSING SYSTEM
Pressure Regulating Valve
Flow Control Valves
Gas Cylinders
Motorised Valves
Nov 21, 2013 18
Five gas cylinders charge at once at regulated pressure 42 ksc
The safety valve operates, if gas pressure is >50ksc.
Four dosing lines - two each at D/A and CPU outlet
Dosing line with one Motorised (MOV) and one Flow control
valve (FCV)
The MOV is fully opened and gas flow is controlled by FCV.
OPERATION AND CONTROL
Nov 21, 2013 19
The injection control isautomatically adjusted by
Condensate water flow and Feed DO.
OXYGEN DOSING OPERATION
Nov 21, 2013 20
CONVERSION TO OT - ACTIVITIES
Pre OT Activities
Instruments Installation – DO meter, ACC
Install Sampling lines – ACC, pH, K at each CPU Vessel
Replacement of De-aerator O/L sample line by Feed water line to analyzer for round the clock monitoring of Feed DO.
PORTABLE D.O. METER
PORTABLE A.C.C. METER
Nov 21, 2013 21
CPU Availability 100% CPU availability Formal training to Shift –Chemist regarding CPU operation.
Training Session The training session for operators regarding OT & Actions to be taken during start-up, shut-down and in normal
operation.
Database Recording and observing parameters for three months before
start comprising Feed & CEP DOMonitoring of ACC of cycle chemistry under AVT condition to
ensure the readiness of boilers for conversion to OT.
OT CONVERSION - ACTIVITIES
Nov 21, 2013 22
U#3, Feed Water D.O. in AVT
0.00
5.00
10.00
15.00
20.00
25.00
01.01
.2013
10.01
.2013
12.01
.2013
19.01
.2013
24.01
.2013
31.01
.2013
06.02
.2013
08.02
.2013
10.02
.2013
13.02
.2013
15.02
.2013
19.02
.2013
20.02
.2013
25.02
.2013
26.02
.2013
Day(s)
Diss
olve
d O
xyge
n (p
pb)
Feed Water
U#3, Feed and MS ACC value in AVT
0.00
0.05
0.10
0.15
0.20
04-12
-2012
08-12
-2012
13-12
-201
225
-12-20
1201
.01.201
310
.01.201
319
.01.201
324
.01.201
331
.01.201
304
.02.201
309
.02.201
313
.02.201
318
.02.201
325
.02.201
326
.02.201
3
Day(s)
ACC
(uS/
cm)
Feed WaterMain Steam
DO/ACC DATA TREND BEFORE OT
U#2, Feed Water D.O. in AVT
0.00
5.00
10.00
15.00
20.00
25.00
11-12
-2012
18-12
-2012
25-12
-2012
01-01
-2013
08-01
-2013
15-01
-2013
22-01
-2013
29-01
-2013
05-02
-2013
12-02
-2013
19-02
-2013
26-02
-2013
05-03
-2013
Day(s)
Dis
solv
ed O
xyge
n (p
pb)
Feed Water
U#2, Feed and MS ACC value in AVT
0.00
0.05
0.10
0.15
0.20
11-12
-2012
13-12
-2012
20-12
-2012
29-12
-2012
01.01
.2013
08.01
.2013
15.01
.2013
21.01
.2013
28.01
.2013
04.02
.2013
11.02
.2013
18.02
.2013
25.02
.2013
02.03
.2013
04.03
.2013
08.03
.2013
Day(s)
ACC
(uS/
cm)
Feed WaterMain Steam
Nov 21, 2013 23
COMMISSIONING ACTIVITIES.
Instrument Checking Calibration of all pressure gauges and transmitters
Checking of following for protection of FCV.
• Pressure regulating valve & set at 42ksc
• Pressure safety valve & set at 50ksc.
Valve Operation Checking of all MOVs and FCVs for local and remote
operation.
Leak Detection Test Pressurizing of dosing lines
Checking for any gas leakage at every weld-joint.
Nov 21, 2013 24
BALLOONBALLOON
GAS FLOW MEASUREMENT & FCV SETTING
Most important activity as dosing of oxygen gas with in limit is dependent on FCV setting.
Measurement of gas flow using Balloons (spherical and cylindrical) and a connector
Nov 21, 2013 25
Based on DO data of different units, decision to start OT first in one unit.
Steady rate of passivation, [target value of DO is set max. 80 ppb (range 30 -150 ppb)].
Initially operation at 9.0 to 9.2 pH and then slowly and steadily convert to lower value by monitoring Feed ACC.
Afterwards operate DO level at 80 -110 ppb range.
CONVERSION TO OT - GUIDELINES
Nov 21, 2013 26
CONVERSION TO OT – Case study
Case study 1: Oxygen dosing started The D/A vents fully closed and oxygen dosed at CPU O/L. Feed DO started increasing from 6.8 ppb to 20 ppb within 10hrs After two days, Feed DO attained 20-40 ppb range only Additionally the dosing carried out at D/A O/L as minor passing
was observed from D/A vent. After that, DO increased to 65-80 ppb. The target value achieved within 5days of start of OT. In the second phase, operation started at DO level of 80-110
ppb.
Nov 21, 2013 27
U#3 Feed Water D. O. in initial month (March, 2013)
0.00
20.00
40.00
60.00
80.00
100.00
120.00
02.03
.2013
04.03
.2013
05.03
.2013
05.03
.2013
07.03
.2013
08.03
.2013
11.03
.2013
14.03
.2013
15.03
.2013
16.03
.2013
25.03
.2013
01.04
.2013
Days
Disslov
ed O
xyge
n (ppb
)
U#3 Feed Water D. O. trend upto July, 2013
0.00
20.00
40.00
60.00
80.00
100.00
120.00
140.00
02.03
.2013
05.03
.2013
07.03
.2013
11.03
.2013
15.03
.2013
18.03
.2013
01.04
.2013
29.04
.2013
11.05
.2013
18.05
.2013
20.05
.2013
27.05
.2013
17.06
.2013
08.07
.2013
Days
Dissl
oved
Oxy
gen
(ppb
)
CONVERSION TO OT – Case Study
Nov 21, 2013 28
CONVERSION TO OT – Case Study
Case study 2:
Oxygen dosing started
The D/A vents fully closed
Oxygen dosed at CPU O/L & D/A outlet simultaneously
Feed DO started increasing from 9.2 ppb to 40 ppb within 48hrs
After three days, Feed DO attained 50 ppb range
The target value achieved within 5days of start of OT.
In the second phase, operation started at DO level of 80-110 ppb.
Nov 21, 2013 29
U#2 Feed Water D. O. trend in March, 2013
0.0
20.0
40.0
60.0
80.0
100.0
15-Mar-
13
17-Mar-
13
19-Mar-
13
21-Mar-
13
23-Mar-
13
25-Mar-
13
27-Mar-
13
29-Mar-
13
31-Mar-
13
Days
Disslov
ed Oxy
gen (ppb
)
U#2 Feed Water D. O. trend upto 29th July, 2013
0.00
20.00
40.00
60.00
80.00
100.00
120.00
15.03
.2013
16.03
.2013
25.03
.2013
15.04
.2013
29.04
.2013
13.05
.2013
20.05
.2013
27.05
.2013
17.06
.2013
27.06
.2013
Days
Disslov
ed O
xyge
n (p
pb)
CONVERSION TO OT – Case Study
Nov 21, 2013 30
U#3, Avg ACC value
0.00
0.05
0.10
0.15
0.20
Dec'12
Jan'1
3
Feb'1
3
Mar'13
Apr'13
May'13
Jun'1
3
Month
ACC
(uS/
cm)
Feed WaterMain Steam
AVT v/s OT – DATA COMPARISON
U#2, Avg ACC value
0.00
0.05
0.10
0.15
0.20
Dec'12
Jan'1
3
Feb'13
Mar'13
Apr'13
May'13
Jun'1
3
Month
AC
C (u
S/cm
)
Feed WaterMain Steam
Feed and Main Steam ACC The Feed and MS A.C.C. values of OT - almost stable (0.09-
0.10 μS/cm)
Values are less in comparison to AVT (0.2 μS/cm)
Nov 21, 2013 31
U#3, Avg Iron value
012345678
Dec'12
Jan'1
3Feb
'13Mar'
13Apr'
13May
'13Ju
n'13
Jul'13
Aug'13
Month
Iron
(ppb
)
Feed WaterMain steam
U#2, Avg Iron value
012345678
Dec'12
Jan'1
3Fe
b'13
Mar'13
Apr'13
May'13
Jun'1
3Ju
l'13Aug
'13
Month
Iron
(ppb
)
Feed WaterMain steam
Feed and Main Steam Iron values Rise in Feed and MS iron values of OT at the start (3-4 ppb)
and decrease afterwards (2-3 ppb)
Values lesser in comparison to AVT (more than 5 ppb).
AVT V/S OT – DATA COMPARISON
Nov 21, 2013 32
BENEFITS of OT over AVT50% increase in CPU load
AVT - 240000 M3 load
OT - 360000 M3 load
Environmental benefits and Safety
Increase in CPU loading results decrease in regeneration frequency.
Reduction in spent regenerant waste. Environmental benefit.
Reduction in Ammonia consumption by 64%
Reduction in DM Makeup (Cyclic)
Cyclic make up reduction ( less than 1%)
AVT- D/A vents open; OT - close/throttle the vent
Nov 21, 2013 33
Reduction of chemical cost :
ChemicalConsumption (Ltr)AVT OT
Cost (in Rs) AVT OT
Ammonia 1100 400 39600 14400
Oxygen (No. of Cyl.) -- 15 -- 1950
Total Cost ( in Rs) 39600 16350
MONTHLY SAVINGS (in Rs): 39600-16350 = 23250/-
(monthly average values of chemicals consumed is taken, and current price is considered)
BENEFITS of OT over AVT
Nov 21, 2013 34
CPU- RegenerationReduction in monthly consumption of HCl & NaOH as CPU loading is increased by 50%.
ChemicalCONSUMPTION (Ltr)
AVT OT Cost (in Rs)
AVT OT ACID (HCl) 31 MT 20 MT 48050/- 31000/-
ALKALI (NaOH) 8 MT 5 MT 210224/- 131390/-
TOTAL COST (in Rs) 258274/- 162390/-
Total monthly savings (in Rs.) = 23250.00 + 95884.00 = Rs. 119134/-.
BENEFITS of OT over AVT
* Cost of HCl is taken as Rs.1550/MT and Alkali as Rs. 26278/mt. thus monthly savings of Rs. 95884/-
Nov 21, 2013 35
RESULTS AND CONCLUSIONS
The judicious and efficient CPU operation helps to maintain stringent Feed -water quality.
Increase in the Feed DO range to 80-110ppb, and maintaining ACC in the range of 0.09-0.11 S/cm.
Stabilization of steam water cycle chemistry - evident from the analytical parameters & CPU cleaning process (hematite layer conversion)
Success factor of conversion to OT will be more promising after physical inspection of boiler components
Nov 21, 2013 36
TRANSFORMING LIVES