partnership to advance clean energy-deployment (pace-d)...

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

12

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

14

U6 - Boiler Tube Misalignment

15

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

17

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%.

18

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

19

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

20

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.

21

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”

22

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

23

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.

24

Gravimetric Coal Feeders are recommended Volumetric Coal Feeders Installed

Fuel Flow Measurement Considerations

25

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

27

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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

29

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.

30

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

31

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

33

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 !

38

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

40

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

42

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)


03-06-13

N. LY S. Storm 1006-100-006-001

NTS

SAPH Gas Inlet Test Locations w/ Multipoint (Top View)


03-06-13

N. LY S. Storm 1006-100-006-002

NTS

N


03-06-13

N. LY S. Storm 1006-100-006-003

NTS

N

SAPH Gas Outlet Test Locations wi/Multipoint (Top View)


03-06-13

N. LY S. Storm 1006-100-006-004

NTS

N

PAPH Gas Inlet Test Locations w/ Multipoint (Top View)


03-06-13

N. LY S. Storm 1006-100-006-005

NTS

PAPH Gas Inlet Test Locations w/ Multipoint (Top View)

N


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.


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)


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


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


HVT Location West View HVT Location East View

8 Ports Total


PAPH Gas Inlet PAPH Gas Inlet

5 Ports Total

Unit 6 PAPH Gas Inlet Test Locations


SAPH Gas Inlet SAPH Gas Inlet

6 Ports Total

Unit 6 SAPH Gas Inlet Test Locations


PAPH Gas Outlet PAPH Gas Outlet

5 Ports Total

Unit 6 PAPH Gas Outlet Test Locations


SAPH Gas Outlet SAPH Gas Outlet

6 Ports Total

Unit 6 SAPH Gas Outlet Test Locations


Primary Air Duct Primary Air Duct

Unit 6 Primary Air Duct Test Locations

Recommend install new test ports


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


Plant testing equipment available onsite


Coal fineness equipment available onsite


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

65

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