Eric Liese

Office of Research and Development

2014 GCC Conference - Orlando, FL

Sept. 30 – Oct. 2, 2014

Simulation of a Combined Cycle using Dynsim

Mobile App: Please take a moment…

Check into Session by:

• Select Detailed Schedule

• Select the specific session

• Click on “Check in”

Take Session Survey by:

• Select Detailed Schedule

• Select the specific session

• Scroll Down to “Survey” and Provide Feedback

NETL IGCC Simulator Integrated Control Room and Field Operations

InTouch OTS Display

Dynamic Simulator/OTS

Control Room

Eyesim 1.0 ITS Displays and Animations

3D ITS

Virtual Energy Plant

Real-Time

Data and

Communication

Link

• Operations

• Controls

• Alarms

• Malfunctions

• Plant Familiarization

• Field Operations

• Equipment Animations

• Malfunctions

Natural Gas Combined Cycle (NGCC) Dynamic Simulator

• Established cooperative research

agreement - CRADA - with Schneider

Electric

– Leverage combined cycle portion of IGCC to

make a NGCC dynamic simulator

• Completed NGCC steady-state design

– GT PRO (Thermoflow)

– 2-on-1 design with 574 MW gross power

– Two GTs (182MW each) x One ST (210MW)

– Two 3-pressure HRSGs (1890, 385, and 62 psia)

• Completed modifications and dynamic

testing of DYNSIM model

– Modified HRSG heat exchangers and drums

– Modified steam turbine to match new conditions

– Achieved stable full-load and tested ramping

• Current work

– NGCC Cycling Simulation Studies with the

National Rural Electric Cooperative - NRECA

NGG Plant

Design in

GT PRO

Combined Cycle Section of IGCC

Gasification Boundary

Simple NGCC Schematic

Start load reduction.IGV closes to maintain EGT (exhaust gas temp of GT)

IGV limit.EGT decreases

Hold at 18.5 MW

GT trip at 0 MW

0.00E+00

5.00E+05

1.00E+06

1.50E+06

2.00E+06

2.50E+06

3.00E+06

3.50E+06

4.00E+06

0.00E+00

2.00E+02

4.00E+02

6.00E+02

8.00E+02

1.00E+03

1.20E+03

1.40E+03

0 500 1000 1500 2000 2500 3000

Flo

w

Tem

pe

ratu

re, P

ow

er

Time [sec]

2-on-1 Combined Cycle GT2 Shutdown - Final SH

GT Power [MW]

Final SH Steam In [F]

Final SH Steam Out [F]

Final SH Gas In [F]

Final SH Gas Out [F]

Sec. SH Steam Out [F]

Final SH Steam Flow [pph]

GT Flow [pph]

Desuperheater effect

Load decrease ~ 10 MW/min

Liese, E.A. and S.E. Zitney, “A Dynamic Process Model of a Natural Gas Combined Cycle – Model Development

with Startup and Shutdown Simulations,” Proc. of ASME 2013 Power Conference, Boston, MA, July 29 – August 1, 2013

0.00E+00

5.00E+05

1.00E+06

1.50E+06

2.00E+06

2.50E+06

3.00E+06

3.50E+06

4.00E+06

0.00E+00

2.00E+02

4.00E+02

6.00E+02

8.00E+02

1.00E+03

1.20E+03

1.40E+03

33000 33500 34000 34500 35000 35500 36000

Flo

w

Tem

pe

ratu

re, P

ow

er

Time [sec]

GT1 and ST Running - GT2 Hot Hold Startup - Final SH

GT Power [MW]

Final SH Steam In [F]

Final SH Steam Out [F]

Final SH Gas In [F]

Final SH Gas Out [F]

Sec. SH Steam Out [F]

Final SH Steam Flow [pph]

GT Flow [pph]

Open exhaust damper

Light off -No purge

GT synch

IGV temperaturematching

IGV max

Desuperheater on

20 to 80 MW

NRECA NGCC Power Plant Cycling Project Description

• Use generic NGCC dynamic simulator to:

– Examine typical cycling operations

– Investigate practical engineering approaches and

operational procedures

– Reduce thermal and pressure transients to

minimize equipment stress

• Simulate high-frequency, high-impact scenarios

– Startup/Shutdown

• Cooperating with NGCC plant in Dell, AR.

Associated Electric Cooperative, Inc.

AECI

supplies

electricity in

three states

Dell Power Plant

• 2-on-1 Combined Cycle.

– Two GE7FA CT’s each exhausting to a three

pressure HRSG

– One GE D11 ST

• Duct burning in HRSG’s for increased steam output

if needed. HP steam around 1800 psi with duct

burner(s) on, 1300 psi with burners off.

• On 95°F day, 151 MW each CT and 165 MW ST

without duct burners on.

• Used as a peaking plant.

• In order to model plant Dell, needed to modify HRSG.

Completed.

• Need to tune CT model. Partially complete.

0

20

40

60

80

100

120

140

160

1040

1060

1080

1100

1120

1140

1160

1180

1200

1220

10:42:14 AM 10:45:07 AM 10:48:00 AM 10:50:53 AM 10:53:46 AM 10:56:38 AM 10:59:31 AM

Po

we

r (M

W)

Tem

pe

ratu

re (

F)

Time

Power ↑ - Exhaust Gas Temperature

EGT (F)

Power (MW)

Example Data

Full Load (155 MW) Steam Temperatures

• Gas Flow

– Components in the HRSG - hot to cold • HP Final Superheater - 731°F to 1036 °F

• Secondary Reheater - 863 °F to 1023 °F

• Duct Burner

• Primary Reheater - 677 °F to 863 °F

• Primary Superheater - 578 °F (sat.) to 852 °F

• HP Drum and Evaporator

• Observation

– In a system with duct burners:

• Steam flow is lower with duct burners off. Higher ΔT across

final SH and thus more attemperator spray flow needed.

• Wider range of ΔT’s across SH’s and attemperation needs.

Observations

• Startup/Shutdown SH condensation not an obvious

issue at Dell. Not likely to implement “purge credit”.

• “Fast Start” not needed at Dell, but shorter time at

low CT load (low efficiency, high emissions) and

improved attemperator performance would be

beneficial

• High (but normal) EGT Isothermal limit ~1210°F

• SH Attemperator valve full open from 60 MW and up

• Spray down to saturation during transients

• Start-up-heat-up longer than shut-down-cool-down

• Need to consider header steam heating/cooling1.

1. Anderson, R., and Pearson, M., “Influences of HRSG and CCGT Design and Operation on the Durability of Two-Shifted HRSG’s”,

European Technology Development Conference on HRSG Technology, London, November, 2003

Conclusions

• Investigate

– Earlier ramp to above “Mode 6”: Reduce heat-up

time… extend cool-down?

– Load ramp rate from Minimum to ~120 MW

– IGV temperature matching

– Attemperator “performance”

– HP drum pressure