2014 GCC Conference - Orlando, FL Sept. 30 Oct. 2, Simulation of a Combined Cycle using Dynsim. Eric Liese Office of Research and Development

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1 2014 GCC Conference - Orlando, FL Sept. 30 Oct. 2, 2014 Simulation of a Combined Cycle using Dynsim Eric Liese Office of Research and Development

2 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

3 NETL IGCC Simulator Integrated Control Room and Field Operations InTouch OTS Display Eyesim 1.0 ITS Displays and Animations Operations Controls Alarms Malfunctions Dynamic Simulator/OTS Control Room Real-Time Data and Communication Link Plant Familiarization Field Operations Equipment Animations Malfunctions 3D ITS Virtual Energy Plant

4 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

5 Combined Cycle Section of IGCC Gasification Boundary

6 Simple NGCC Schematic

7 Temperature, Power Flow 1.40E E+03 2-on-1 Combined Cycle GT2 Shutdown - Final SH Start load reduction. IGV closes to maintain EGT (exhaust gas temp of GT) IGV limit. EGT decreases 4.00E E E+03 GT trip at 0 MW 3.00E E+02 Desuperheater effect 2.50E+06 GT Power [MW] Final SH Steam In [F] 6.00E+02 Hold at 18.5 MW 2.00E E+06 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] 4.00E+02 Load decrease ~ 10 MW/min 1.00E+06 GT Flow [pph] 2.00E E E E Time [sec] 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

8 Temperature, Power Flow 1.40E+03 GT1 and ST Running - GT2 Hot Hold Startup - Final SH IGV max 4.00E E+03 IGV temperature matching 3.50E E+03 GT synch 3.00E+06 Desuperheater on 2.50E+06 GT Power [MW] 8.00E+02 Final SH Steam In [F] 2.00E+06 Final SH Steam Out [F] Final SH Gas In [F] 6.00E+02 Final SH Gas Out [F] 1.50E+06 Sec. SH Steam Out [F] Final SH Steam Flow [pph] 4.00E+02 Open exhaust damper 20 to 80 MW 1.00E+06 GT Flow [pph] 2.00E E+05 Light off - No purge 0.00E E Time [sec]

9 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.

10 Associated Electric Cooperative, Inc. AECI supplies electricity in three states

11 2-on-1 Combined Cycle. Dell Power Plant 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.

12 Temperature (F) Power (MW) 1220 Example Data Power - Exhaust Gas Temperature EGT (F) Power (MW) :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 Time

13 Full Load (155 MW) Steam Temperatures Gas Flow Components in the HRSG - hot to cold HP Final Superheater F to 1036 F Secondary Reheater F to 1023 F Duct Burner Primary Reheater F to 863 F Primary Superheater 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.

14 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/cooling 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

15 Investigate Conclusions 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