Partnership to Advance Clean Energy-Deployment (PACE-D) Technical Assistance Contract Chandrapur Heat Rate Improvement Program S. Storm, SSI A.K. Arora, NTPC Nexant Technical Support Team 8 March 2013
Partnership to Advance Clean Energy-Deployment
(PACE-D) Technical Assistance Contract
Chandrapur Heat Rate Improvement Program
S. Storm, SSI A.K. Arora, NTPC Nexant Technical Support Team
8 March 2013
2
Primary Objectives:
• Insure all site personnel (especially key personnel) have awareness of the heat rate program, purpose and benefits. – Both short & long term
• Establish a formal heat rate program for Unit-6 to serve as the foundation and example for the plant to help assess ”low-hanging fruit” and site specific opportunities.
3
Targets:
• Establish the formal heat rate program in 2013 • Reorganize the plant team (as needed) to implement the program in
2013-2014. • As an initial goal, improve the heat rate by 100-150 kcal within the next 12
months. Then, work towards “Best Achievable” plant performance
4
Heat Rate Improvement Program Process Overview
Existing Plant Equipment Design “As Found”
Plant Equipment Performance
Capable of meeting Objectives? Yes
Audit Conduct a Comprehensive Diagnostic Assessment /
Performance Audit
Evaluate the plants performance results; Establish
goals and processes for improvement; Develop Best Practices & Manage them
Improve & Preserve Performance
Meet Target?
Gap Analysis
Yes
No
Utilize Performance Monitoring Software Air, Fuel, Ash & Gas Management Systems
March 2013 Audit, Review Objectives, Conduct
Training, Develop Program
Evaluate against Design and ‘Best in Class’ Standards
Tool Box
6
Initial Chandrapur Unit-6 Observations
1. Efficiency, Heat Rate & Performance § Boiler Performance (see following slides)
§ Firing System equipment § Air In-Leakage § Air-Gas Management Systems
§ Turbine Cycle Performance (see following slides)
2. Unit Reliability
3. Load Generation Capability 4. Coal Quality and Consistency of Coal Supply 5. Instrumentation, Control & Archiving Capability for Plant Heat Rate
Performance Monitoring & Reaction 6. Plant Safety
§ Ie. Handrails, cleanliness, leaky insulation, coal & ash leaks, etc.
7
Major areas identified for improvement
• Resulting with: – Over-heated and failed tubes – High de-superheating spray flows (both SH & RH)
8
Elevated Furnace Exit Gas Temperatures
• There are no working long retractable soot blowers available on the unit • There are no cleaning provisions for the SH division panels • Mechanical condition of the wall blowers need to be addressed and optimized
9
Boiler Cleaning
Impact of Ash & Slag Build-up on Heat Transfer
As ash builds up on a tubes surface heat transfer is reduced…
Boiler Operation & Design The boiler consists of a series of heat exchangers and each one of these components impacts the overall cycle performance
Furnace Walls & SH RH Economizer Airheater
Air from FD Fan
Energy Losses
Feed water energy from top Feed water heater
To LP From HP Turbine
Steam To HP
Turbine
Feed water to Drum
Fuel Energy Input
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Point at which combustion should be completed
Flame
Quench Zone
Residence time of 1-2 seconds
U6, Boiler Heat Absorption & Furnace Residence Time
Water Walls
Super Heater
Re Heater Economizer
40
30
20
10
Boiler Sections | Typical Subcritical Boiler Absorption
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U6 - Boiler Tube Misalignment
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Fron
t SH
Div
isio
n P
anel
Pla
ten
SH
Ass
embl
y
Rea
r SH
Div
isio
n P
anel
RH
Ass
embl
y
Gas Flow Path
Gas Flow Paths
16
Front SH Division Panel Rear SH Division Panel
SH Platen Assy.
RH Assy.
SH Division Panels are covered with thick slag and do not have cleaning provisions
Location of Recent and Several Tube Failures Failure Type: Fish Mouth (Short-term overheating)
U6 - Boiler Tube Failures
• Current location of (2) existing probes is non-representative. Only one probe on each side of each boiler exit duct.
• Visual observations of secondary combustion in the boiler suggest possible oxygen starvation
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Excess Oxygen Measurement
• Air in-leakage has a negative impact on APH “X” Ratio, ESP performance, Fan Capacity and
Auxiliary Power Consumption • Impact on Fan capacity (especially during the summer-time months). Air in-leakage
exhausting the ID fans can result in reduced load generation. • Actual Data collected from the ID fan discharge locations on March 5th, 2013 revealed ~ 40%
air in-leakage from the control indicated excess oxygen values from the economizer outlet to the measured oxygen at the ID fan. If the furnace exit is “reducing” as suspected, this would infer a leakage value of 50 to 60%.
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System Air In-leakage
Loca%on % O2 CO (PPM) Temp. (C)
A 7.94 732 157.2
B 7.76 1067 158.5
C 8.08 1384 160.3
D 8.34 603 157.4
Avg. 8.03 946.5 158.35
Loca%on % O2
Economizer Inlet 3.3
Economizer Outlet
7.31
ID Fan Inlet 8.03
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Unit-6, Suspected Paths of Air In-leakage
1. Bottom Ash Hopper 2. Penthouse 3. Convection Pass 4. Large Convection Pass Access Doors 5. Economizer Hoppers 6. Air Preheaters 7. Flue Gas Ductwork | Expansion Joints 8. ESP 9. Post ESP Ductwork & ID Fans
1
2 3
4
5
6 7
8 9
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Unit-6, Insulation and Expansion Joint Audit
• Right Side of boiler (elev. 58m) Insulation missing on a 1-2m x 10m area of the convection pass
• Insulation missing on a Large 3-4m x 3-4m area on the left side of economizer hopper
• Too many minor insulation repairs to count on various areas of the unit.
• However, the discrepancies at the Air heater inlet & outlet ducts, expansion joints, etc. must be addressed.
• Ducting, Expansion joints & insulation
replacement should planned sections at a time, with work completed properly.
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Fly ash Particle & LOI Analysis Sample
ID % LOI +200 Mesh %
-‐200 Mesh %
Composite Fly ash 0.62 42 58
BoGom Ash 1.18 96 4
Sample ID
+200 Mesh LOI %
-‐200 Mesh LOI %
Fly ash 0.87 0.3
BoGom Ash 1.89 0.87
200 mesh sieve (coarse particle ash)
Collection Pan (fine particle ash)
This will result with secondary combustion, slag & fouling; Exacerbating problems associated with reducing atmospheres
• Mill performance Concerns – Mill outlet temperature control – Coal rejects | Pyrite Hopper fires – Air-Fuel Distribution
• Burner mechanical tolerances, condition & synchronization of tilts
• Mills must be “blue-printed”
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Firing System Performance
• Pyrite scraper height • Journal • Vane Wheel • Throat gap • Journal profile • Coal feed pipe gap • Inverted cone gap • Internal cone condition • Hydraulic pressure • Outlet cylinder height • Classifier blade timing • Outlet cylinder condition
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Primary Airflow & Vane Wheel Deflector Condition
Improperly sized vane wheels and/or bypassed air around the vane assembly will result with coal rejects to the mill pyrite hoppers. On Unit-6, this is a real problem, while we have observed coal reject conditions on all operational mills.
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Gravimetric Coal Feeders are recommended Volumetric Coal Feeders Installed
Fuel Flow Measurement Considerations
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Heat Rate Improvement Program Requirements
26
Instrumentation Accuracy is Mandatory: Key Performance Indicator examples (partial list):
• Water & Steam Flow • Coal Flow Metering • Furnace Exit Gas Measurement • Excess Oxygen Measurement • Flue gas draft measurements • In conjunction with the plant performance program, the site should consider
upgrading controls from a DAS to DCS System. • In conjunction with that, online performance monitoring software such as GP
Strategies (EtaPro) should be considered. Thermal performance model integration, with advanced pattern recognition and tools that output real-time controllable losses can be extremely valuable. Benefits of online performance monitoring include:
– Ability to Track the Key Performance Indicators (KPIs) – Use tools to identify any site-specific effects for deviations – Provide Information in a timely fashion to act on it – Prepare audits & performance tests to provide additional details
Effective Plant Performance Programs Require: • Periodic performance audits of the plant equipment, including:
– Boiler Efficiency Evaluations (required) – Turbine Performance Testing (required) – Cycle Isolation Checks (required) – Steam Path Audits (required) – Evaluation of Controllable Losses (required)
• Cycle Losses (ie. Condenser, heaters, vents, drains) • Boiler Losses (measured & stealth)
– Electrical Output Testing (recommended) – Auxiliary Power Consumption Audits (recommended)
• Communication & Reporting of Results • Performance and/or Strategic meetings • Educational Training & Knowledge Transfer required to employ protocols and
performance tests
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Fuel Preparation • Fuel feed & control • Fuel feed quality and sizing
Mechanical tolerances § Mill, Airflow Elements, Burner and Control
dampers must be optimal Fuel Line Performance
• Balance and Distribution • Particle Sizing of coal fineness to >75%
passes a 200 mesh screen and >99% passing a 50 mesh screen
Combustion Airflow Measurement
• Airflow should be accurately measured & controlled to ±3 % accuracy.
• Air/fuel ratio accurately controlled. Ensuring at least 800 – 850lbs of air for each MMBTU of fuel input.
• Airflow calibration, measurement, staging, equalization & distribution is critical.
Performance Considerations
Furnace Exit Gas Temperature & Flue Gas Constituent Measurements
• Ensure the boiler exit is oxidizing w/ no point less than 2% oxygen
• Ensure all samples used for operation are representative
Economizer Outlet Flue Gas Measurements
• Verify accuracy of excess oxygen probes and if there may be boiler air in-leakage upstream of the APH
System Air In-Leakage Measurements • Furnace to the stack
Evaluation / Assessment of Controllable Factors
• Heat Rate • Efficiency • Emissions • Reliability
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Heat Loss Components Units Value
Losses due to unburned carbon in total dry refuse % .67
Losses due to heat in dry flue gas % 8.47
Losses due to moisture in the “as-fired” fuel % 3.2
Losses due to moisture from burning hydrogen % 4.23
Losses due to moisture in air % .49
Losses due to air infiltration* % .45
Radiation, Unmeasured Losses & Manufacturers Margin ** % 1.5
Boiler Efficiency % 81.05
Abbreviated Boiler Efficiency Test Results
*This Assumes the furnace exit gas oxygen level is 2%. I expect actual is much less, but gave the boiler the benefit of my doubts ** The design value for this is 1.09%. Actual is expected to be much greater. Thus, 1.5% was used.
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Plant Heat Ratedesign =Turbine Cycle Heat Rate(kCal)
Boiler Efficiency %( )=196588.1
= 2,230kCal
Plant Heat Rate = Turbine Cycle Heat Rate(kCal)Boiler Efficiency %( )
=203381.05
= 2,508kCal
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0
20,000,000
40,000,000
60,000,000
80,000,000
100,000,000
120,000,000
140,000,000
160,000,000
500.0
550.0
600.0
650.0
700.0
2,25
0
2,27
5
2,30
0
2,32
5
2,35
0
2,37
5
2,40
0
2,42
5
2,45
0
2,47
5
2,50
0
2,52
5
2,55
0
2,57
5
2,60
0
Year
ly F
uel C
ost (
U.S
.D.)
Year
ly F
uel C
ost (
Cro
res)
Heat Rate (Kcal/KWhr)
Fuel Cost vs. Heat Rate
Economic Considerations
500MW unit, operating at 7,000hrs/year w/ Rs.2500/ton
250kCal Deviation
Rs. 125 Cr.
32
Abbreviated Gross Turbine Cycle Heat Rate Performance Assessment
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Sl#No.# Description# Heat#Rate#(Kcal#/#Kwh)#1" Test"GTCHR"" 2026#2" Test""Corrected"GTCHR"(Corrected"for"CW"I/L"
temp"of"28.7°C"/"D=30°C)"2033#
3" Design"GTCHR"(VWO)" 1965#4" Total"Deviation"in"GTCHR" 68#5" Condenser"loss"due"to"CW"flow"/"Heat"load" 13"6" Condenser"loss"due"to"dirty"tube"/"air"ingress" 27"7" HP"Turbine"Efficiency"(83.1%"/"D"="88.76%)" 16"8" IP"Turbine"Efficiency"(91.37%"/"D"="91.41%)" ="9" FW"temp"of"Eco"Inlet"(252.87°C/"D"=255.7°C)" 3"10" MS"Temperature"(547.3°C/"D"=537°C)" =10"11" MS"Pressure"(165.2"Ksc"/"D"=170"Ksc)" 3"13" HRH"Temperature"(543.5°C/"D"=537°C)" =3"14" RH"Spray"flow"(42"t/hr)" 10"15" Total"accountable"losses" 59#16" Unaccountable"losses" 9#
The computations and observations are based on the measurements available in unit DAS. Several critical parameters need to be cross checked for accuracy. A list has been provided
Gross Turbine Cycle Heat Rate
• Condenser water box DP was high (0.88, 0.76ksc); this indicates choking in condenser tubes.
• It is suggested to clean the condenser tubes during opportunity and optimize the chemical dozing in CW system to avoid hard deposits.
• It is suggested to revive condenser online tube cleaning system • Carry out eddy current test of condenser tubes to assess tube conditions and
replacement of tubes • The air suction depression was 4.6 deg C. Vacuum pump air flows in the two pumps
were measured as 68 & 28 kg/hr respectively. • It is suggested to stop one vacuum pump to confirm any air-ingress in condenser. • In case the vacuum is maintained with one pump weekly changeover schedule to be
practiced to ensure the reliability of the standby pump. • In case of air-ingress, IRT thermography and Helium leak detection test may be used to
identify air-ingress location. • The two high energy drain valves found passing (MS line strainer drain valve before ESV
– 2 & Drain before HPCV – 4). • It is suggested to provide thermocouples down streams of high energy drain valves for
online monitoring of passing. 34
Condenser Performance Evaluation & Recommendations
• The capability test of cooling tower should be carried out including CW flow measurement using an ultrasonic flow meter or by a pitot traverse.
• The airflow measurement at cooling tower fan outlet may be measured along with fan power measurement. The high specific power consumption of CT fan indicates the choking of fills of cooling tower.
• It was informed that design outlet temperature of cooling tower is 34 deg C vis-à-vis design CW inlet temperature of 30 deg C to condenser.
• Options of up-gradation of cooling tower may be explored in consultation with CT vendors.
35
Cooling Tower Performance Assessment & Recommendations
36
Critical Control Parameters that need to be checked for accuracy
37
Closing Considerations • Be clear with communication • Establish the Champions and division of responsibility (DOR) • Combine the teamwork of the entire plant (Operations, Maintenance, Engineering, Management) • Gain Commitment • The Do Something vs. DO NOTHING approach is ALWAYS best • Cultivate Opinions and Create a Responsible Plant Culture with a “Lets go see” attitude • Understand how to trouble shooting problems and do it in a timely manner • Encourage Knowledge Transfer and the deployment of “Best Practices” • Conduct internal audits and stay on top of the low hanging fruit. Optimization is ongoing and must
be implemented as an ongoing program. So, don’t make it so complicated that it’s not executed. • Harvest the low hanging fruit first by identifying the gaps and close the one’s you can control • Plan the long-term recommendations accordingly and be driven by the data results • Maintain good reports for all activities and details included. • Establish the frequency for functional checks and reports required • Use the Work smarter, not harder approach. As you continue through this journey, testing and
processes for performance optimization should become easier and “user friendly” • Management should Create Incentives and Reward Excellence • Performance optimization is a never ending cycle. Keep it up & Work Safely !
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Heat Rate Improvement Program Continuation
• The Next Steps (Short Term)
– Our technical team will draft a formal report and guideline with procedures, protocols and recommendations to establish a formal heat rate program at the Chandrapur Thermal Power Station.
– CTPS team should begin working on low-hanging fruit areas identified and discussing an action plan for improving areas such as boiler tube misalignment, required provisions for furnace exit gas measurements with an HVT, duct leakage repairs, boiler cleaning improvements / ash management, etc.
– After the report and formal heat rate program is completed, we would like to exchange information, discuss the next steps that need to be taken to meet the plants objectives.
39
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S.U. Gohotre Chief Engineer
R.P. Burdle Dy. Chief Engineer
210 MW
S.M. Martkar SE POG
H.J. Jambhore SE CHP A
R.S. Raut SE M-I
U.M. Raut SE E-I
P.K PoneKarv SE-(O)-I.
S.M. Dellwanl Dy. Chief Enginner
500 MW
K.M. Upganlawar SE CHP B
R.K. Oswal SEM-II
S.M. Marudkar
R.K. Oswal SEM-(O)-IIA
S.M. Ramteke SEM-(O)-II-B
Sawaitol Dy. Chief Engineer III
Admin
M.P. Masram SE RP
Gadrye SE Civil
U.D. Raut Medical Supdt
D.S. Dhakate Dy. Chief Engineer-IV
MPD & FQAD
Personnel Management • Identify the Champions • Member Identification • Team Work • Consistency • Sustainability
Appendix
Chandrapur Thermal Power Station, Unit 6 Recommended Test Location Drawings
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FEGT monitoring
Tube Metal Thermocouple System
Ensure Furnace Exit Performance Monitoring Tools are all working and available
Chandrapur Thermal Power Station Unit 6
03-06-13
N. LY S. Storm 1006-100-006-010
NTS
Side Elevation Test Locations
HVT Test 8 ports 54.80 M Elevation
PAPH Gas Outlet 5 ports
SAPH Gas Inlet Test Location 6 ports
PAPH Gas Inlet Test Location 5 ports
SAPH Gas Outlet 5 ports
Dirty Air Test Locations
Primary Air Test Locations
Unit 6 HVT Test Locations (Elevation 54.80 M)
Chandrapur Thermal Power Station Unit 6
03-06-13
N. LY S. Storm 1006-100-006-001
NTS
SAPH Gas Inlet Test Locations w/ Multipoint (Top View)
Chandrapur Thermal Power Station Unit 6
03-06-13
N. LY S. Storm 1006-100-006-002
NTS
N
Chandrapur Thermal Power Station Unit 6
03-06-13
N. LY S. Storm 1006-100-006-003
NTS
N
SAPH Gas Outlet Test Locations wi/Multipoint (Top View)
Chandrapur Thermal Power Station Unit 6
03-06-13
N. LY S. Storm 1006-100-006-004
NTS
N
PAPH Gas Inlet Test Locations w/ Multipoint (Top View)
Chandrapur Thermal Power Station Unit 6
03-06-13
N. LY S. Storm 1006-100-006-005
NTS
PAPH Gas Inlet Test Locations w/ Multipoint (Top View)
N
Chandrapur Thermal Power Station Unit 6
03-06-13
N. LY S. Storm 1006-100-006-006
NTS
Primary Air Duct Test Locations (Side & Front View)
Side View
Front View
Note: Recommend installing test ports on top of primary air ducts.
Chandrapur Thermal Power Station Unit 6
03-06-13
N. LY S. Storm 1006-100-006-007
NTS
Fuel Pipe Test Locations
Notes: 1.) The 1-1/4” connections must fit a 1.050 sample probe 2.) The Ball valve assembly should be + 1/8” of the same length “X” for maximum productivity of test team (to avoid difference in probe markinging)
Dirty Air Probe and Air/Fuel Ratio Connections 1-1/4” (31.75 mm) Full port ball valve 1-1/4” (31.75 mm) NPT close nipple 1-1/4” (31.75 mm) Half coupling
½” (12.7 mm) NPT Plugs For clean air taps (2 at 90 apart)
6” (152.4 mm)
26” (660.0 mm)
Chandrapur Thermal Power Station Unit 6
03-06-13
N. LY S. Storm 1006-100-006-008
NTS
Fuel Pipe Test Locations
10 Diameters Upstream 5 Diameters Downstream
5 Diameters Upstream 2 Diameters Downstream
Chandrapur Thermal Power Station Unit 6
03-06-13
N. LY S. Storm 1006-100-006-009
NTS
Fuel Pipe Equal Area Traverse Grid
Appendix II
Chandrapur Thermal Power Station Unit 6 Photo References
Unit 6 HVT Test Locations
Chandrapur Thermal Power Station Unit 6
HVT Location West View HVT Location East View
8 Ports Total
Chandrapur Thermal Power Station Unit 6
PAPH Gas Inlet PAPH Gas Inlet
5 Ports Total
Unit 6 PAPH Gas Inlet Test Locations
Chandrapur Thermal Power Station Unit 6
SAPH Gas Inlet SAPH Gas Inlet
6 Ports Total
Unit 6 SAPH Gas Inlet Test Locations
Chandrapur Thermal Power Station Unit 6
PAPH Gas Outlet PAPH Gas Outlet
5 Ports Total
Unit 6 PAPH Gas Outlet Test Locations
Chandrapur Thermal Power Station Unit 6
SAPH Gas Outlet SAPH Gas Outlet
6 Ports Total
Unit 6 SAPH Gas Outlet Test Locations
Chandrapur Thermal Power Station Unit 6
Primary Air Duct Primary Air Duct
Unit 6 Primary Air Duct Test Locations
Recommend install new test ports
Chandrapur Thermal Power Station Unit 6
H Fuel Pipe F & H Fuel Pipes
Unit 6 F & H Fuel Pipe Test Locations
6.0”
45° 45°
6.0”
45° 45°
Recommend install test ports 6.0” above
tap valves
Chandrapur Thermal Power Station Unit 6
Plant testing equipment available onsite
Chandrapur Thermal Power Station Unit 6
Coal fineness equipment available onsite
Chandrapur Thermal Power Station Unit 6
Bomb Calorimeter & Furnaces available onsite
Heat Rate Improvement Program Benefits
Save Fuel & Lower Generation Costs
Reduce CO2
Higher productivity From same
Resources is Equivalent to capacity addition
CO2 Mitigation
There is a Strong Correlation between
Reliability and Efficiency
Coal & Chemical Savings
Improved Reliability
Capacity Addition
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