N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

Combined Cycle – 255 MW

Lodi Energy Center

Siemens Flex Plant 30

By Rafael Santana

N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

Agenda

Plant Overview

Plant Availability

Fast Start Advantages

Steam Cycle Differences

Challenges and Lessons Learned

Inspection Photographs

Questions

1

N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

Plant Overview

Siemens SGT6-5000 FD3

Inlet bleed heat

Equipped with CO reduction for low load operations

Siemens TEWAC generator

IP and LP kettle boilers

Nooter Eriksen HRSG

Triple pressure design

Benson HP section

Smaller IP and LP drum

Oxygenated treatment

Siemens SIT

SST-700 HP section

Siemens TEWAC generator

SST-900 combine IP/LP turbine

Siemens T3000 DCS

2

N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

Plant Availability

COD November 27, 2012

Since COD - Availability 98.5%

- Reliability 99.7%

3

Dec-12 Jan-13 Feb-13 Mar-13 Apr-13 May-13 Jun-13 Jul-13

Availability 98.70% 78.90% 97.80% 99.90% 99.70% 38.70% 100% 99.10%

# Starts/Month 33 21 20 12 23 9 21 24

Service Hours 420 314 379 480 540 130 321 497

Standby Hours 314 273 278 264 178 158 399 240

N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

Fast Start Advantages Drum-Type HRSG

•Part load operation during cold and warm starts

•Drum internal components

•Thick-walled HP drum limits ramp rate

•PO4 hide out during start up

Benson Once Through

•Drum replaced with thin walled external separator

•Improved operating flexibility

•Allows high temperature transients

•Faster emissions compliance

•Natural circulation principle

•Less chemicals injected

N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

Fast Start Advantages Combustion Turbine and HRSG Ramp Rate

CT ramp rate @ 13.4 MW/min to 150MW with no limits on cold, warm or hot

Graph below is a cold start

5

N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

Fast Start Advantages Faster Emissions Compliance

6

CONVENTIONAL COMBINED CYCLE WARM START FAST START TECHNOLOGY COLD START

LOAD

MW

RAMP

RATE

GAS

FLOW NOX CO

count

LOAD MW

RAMP

RATE GAS FLOW NOX CO

0 - 3.60 0.0 0 1 0 - 755.6 0.0 0.0

0 - 5.24 2.8 185 2 0 - 955.6 0.0 0.0

0 - 9.18 6.2 1515 3 0 - 1,800.0 53.1 182.9

0 - 11.04 6.7 1795 4 0 - 2,600.0 9.7 2,734.2

0 - 13.65 9.7 1845 5 0 - 3,466.7 11.0 2,424.9

0 - 17.20 13.3 2001 6 0 - 4,200.0 13.3 2,125.7

0 - 18.78 16.5 2001 7 0 - 4,666.7 16.9 2,142.9

0 - 20.87 19.8 2001 8 0 - 5,000.0 22.8 2,421.5

0 - 23.36 22.5 2002 9 0 - 5,200.0 27.0 2,630.3

0 - 24.32 29.6 2001 10 0 13 5,177.8 30.9 2,948.4

0 - 24.64 32.2 2001 11 5 13 5,377.8 32.8 3,084.9

1 - 24.72 36.5 2002 12 17 13 6,111.1 36.4 3,044.2

8 6 26.28 39.3 2001 13 30 13 6,977.8 42.8 2,419.0

68 6 26.74 39.9 2002 14 44 13 8,088.9 45.4 1,362.9

68 6 27.95 42.6 2001 15 57 13 9,111.1 52.2 699.4

68 6 29.36 45.2 2001 16 71 13 10,200.0 42.0 120.0

68 6 30.75 47.3 2001 17 84 13 11,200.0 41.3 4.7

68 6 32.18 48.3 2002 18 98 13 12,266.7 42.3 2.2

68 6 33.14 47.9 2002 19 109 13 13,044.4 38.6 2.1

68 6 34.37 47.0 2002 20 117 13 13,555.6 31.4 2.3

68 6 35.69 46.1 2001 21 127 13 14,222.2 25.0 2.6

68 6 37.15 45.0 2001 22 136 13 14,755.6 19.3 2.4

68 6 38.48 43.4 1930 23 140 13 15,022.2 15.8 1.7

68 6 41.02 43.4 1539 24 140 13 14,955.6 14.4 1.1

68 6 41.09 44.3 1179 25 139 13 14,955.6 12.6 0.7

68 6 42.16 40.9 949 26 140 13 14,955.6 14.0 0.7

68 6 42.29 38.9 684 27 140 13 14,977.8 14.7 0.6

68 6 42.41 36.7 621 28 140 13 14,955.6 15.0 0.5

69 6 42.57 34.2 621 29 140 13 14,977.8 15.4 0.3

69 6 42.64 31.0 598 30 140 13 14,977.8 15.8 0.2

70 6 42.76 28.7 578 31 140 13 14,955.6 16.3 0.2

70 6 42.96 26.5 566 32 140 13 14,955.6 16.6 0.2

71 6 43.03 24.6 527 33 140 13 14,977.8 17.0 0.2

74 6 43.58 23.3 521 34 140 13 14,977.8 17.3 0.1

75 6 44.48 22.6 490 35 140 13 14,955.6 17.4 0.1

76 6 44.70 22.2 382 36 140 13 14,955.6 15.8 0.1

78 6 45.03 22.7 337 37 140 13 14,977.8 9.2 0.1

78 6 45.61 23.3 317 38 140 13 14,977.8 4.8 0.1

79 6 45.72 24.0 248 39 140 13 14,955.6 3.0 0.0

81 6 46.11 25.0 229 40 141 13 14,955.6 2.2 0.0

83 6 47.04 25.8 216 41 140 13 14,955.6 1.6 0.0

84 6 47.37 26.5 147 42 140 13 14,933.3 0.8 0.0

84 6 47.79 27.0 115 43 140 13 14,955.6 0.7 0.0

84 6 47.89 28.0 86 44 140 13 14,955.6 0.6 0.0

84 6 47.99 28.7 78 45 140 13 14,955.6 0.4 -0.1

84 6 48.05 29.1 78 46 140 13 14,933.3 0.3 -0.1

95 6 48.39 29.5 74 47 139 13 14,844.4 0.3 -0.1

95 6 49.77 29.5 71 48 139 13 14,866.7 0.3 -0.1

99 5 51.55 30.0 35 49 140 13 14,911.1 0.3 -0.1

125 4 53.73 32.4 20 50 140 13 14,933.3 0.3 -0.1

125 4 54.28 34.1 11 51 140 13 14,911.1 0.3 -0.1

125 4 55.69 30.3 17 52

125 4 57.13 28.7 15 53

125 4 58.32 27.5 13 54

125 4 59.71 25.4 9 55

125 4 60.91 18.8 6 56

128 5 61.93 12.0 5 57

CO ppmvd corrected

within 23 minutes

of light off

NOX ppmvd

corrected within 41

minutes of lightoff

At 57 minutes of startup CT at 128 MW, NOx &

CO ppmvd not in compliance

N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

Steam Cycle Differences

Cycle Differences

- Oxygenated, high purity water to minimize corrosion and FAC in feedwater

- LEC uses ammonia, condensate polishers and oxygen injection

- No reducing agent allowed (O2 scavenger)

- Condensate pumps directly feed BFW pumps

- BFW pumps feed LP/IP drums and Benson HP section

- IP/LP Kettle boilers receive feedwater from drums

LP steam augments superheater 1 inlet

IP steam augments IP drum

- IP drum has no blowdown, (IP kettle boiler)

- All feedwater provided to Benson OTSG becomes steam in single pass

- LEC has as many analyzers and system drains as a 3x1 combined cycle

plant

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N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

Challenges and Lessons Learned

Combustion Turbine

CO issues with CT during start up

- CT fuel fraction adjustments to help reduce CO

- IGV Adjustment as CT ramps to 50% load

- Inlet heat bleed operation for CO reduction on start up

- CT @ 13.4MW/min ramp rate vs. 10MW/min

These Changes saved up to 350 lbs. of CO per start

8

N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

Challenges and Lessons Learned (cont.)

Heat Recovery Steam Generator

- Bypass tuning for CT faster ramp rates

- Falling lower acoustic baffles due to cycling and lack of support

- Pre-heater #1 lower header weld leak in January

Steam Turbine

- During ST roll, encountered high temp trips across IP exhaust

- ST curves revision (faster starting & loading)

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N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

CT Inspections Found tie wire inside basket 13 Basket 7 “C” stage feed tube cracked

“C” Stage Feed Pipe

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N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

HRSG LP/IP Drum Inspections

11

N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

HRSG Inspections HRSG Acoustic Lower Baffles HRSG Acoustic Baffle Repairs

12

N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

HRSG Inspections HRSG Pre-Heater #1 Leak

13

N O R T H E R N C A L I F O R N I A P O W E R A G E N C Y

14

QUESTIONS