Dynamic Modelling of Fossil Power Plants

Report
DYNAMIC MODELLING OF FOSSIL POWER PLANTS –
INCREASING FLEXIBILITY TO BALANCE
FLUCTUATIONS FROM RENEWABLE ENERGY SOURES
M. Hübel, Dr. J. Nocke, Prof. E. Hassel
University of Rostock
Institute of Technical Thermodynamics
Baku, 23.05.2013
Overview
1.
2.
3.
4.
5.
Motivation
Reference PowerPlant
Simulation and Validation
Example Results
Outlook
Institute of Technical Thermodynamics – Dynamic Power Plant Simulation
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Motivation
German Electric Energy System 2020
Consumer Load
Maximum: ~ 80 GW
Average: ~ 60 GW
GRID FREQUENCY
indicats
deviations in the
energy balance
Installed Capacities
Photovoltaic: ~ 50 GW
Wind:
~ 55 GW
http://meltblog.de/wp-content/uploads/2013/02/Fotolia_45848443_XS.jpg
Institute of Technical Thermodynamics – Dynamic Power Plant Simulation
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Motivation
German Electric Energy System 2020
Annual Consumption
~ 600 TWh/a
GRID FREQUENCY
indicats
deviations in the
energy balance
Annual Production
Photovoltaic: ~ 50 TWh
Wind:
~ 120 TWh
http://meltblog.de/wp-content/uploads/2013/02/Fotolia_45848443_XS.jpg
Institute of Technical Thermodynamics – Dynamic Power Plant Simulation
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Motivation
German Electric Energy System 2020
Annual Consumption
~ 600 TWh/a
GRID FREQUENCY
indicats
deviations in the
energy balance
Annual Production
Photovoltaic: ~ 50 TWh
Wind:
~ 120 TWh
http://meltblog.de/wp-content/uploads/2013/02/Fotolia_45848443_XS.jpg
Institute of Technical Thermodynamics – Dynamic Power Plant Simulation
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Motivation
Role of Fossil Power Plants in the German Electric Energy System
• Most of our consumed electric energy is from thermal power
plants – today and in the next decades
• Some grid services, e.g. Primary Control can currently be done
only by thermal power plants
• (too) little investments for modernization and optimization
within this sector – high potential for optimization
P
Gradmax
Pmin
t
Decreasing
Minimum Load
Increasing
Load Gradients
GOAL: Flexible power plants
Operating Schedule
Institute of Technical Thermodynamics – Dynamic Power Plant Simulation
METHODE: Dynamic Modeling
•
Identify restrictions
•
Develop optimization strategies
•
Comparison of scenarios
6
Reference Power Plant
Jänschwalde Block D
•
•
•
•
•
Year of commissioning:
combustible:
generator output:
Efficiency:
live steam
1985
lignite
530 MW
36%


mass flow rate:
pressure:
2x230 kg/s
162 bar

temperature:
535 °C
Lehrstuhl für Technische Thermodynamik – Dynamische Modellierung des Kraftwerks “Jänschwalde”
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Overview on Power Plant /
Model Structure
Boiler
Turbine
Condensator
LP-Preheaters
Feedwater System
HP-Preheaters
Lehrstuhl für Technische Thermodynamik – Dynamische Modellierung des Kraftwerks “Jänschwalde”
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Fundamental equations
Outlet
Outlet
massflow enthalpy flux
Mass balance
Outlet p
n
dm
  m i
dt i 1
Energy balance
n
dU
  hi m i  Q  Wt
dt i 1
Toutside
Tinside
Momentum balance
n
n
n
d (m c)
  Ai i ci (ci ni )  A0 p f   Ai i ni   Ai i gzi ni
dt
i 1
i 1
i 1
Δp
TFluid
Heat transfer
dT
d 2T
a 2
dt
dr
Q  AT
Inside wall
at boundary layer
according Fouriers
heat transfer equation
α determined by Dittus-Boelter
(1-phase flow) or Chen-correlation
(2-phase flow)
heat flux
Inlet p
Inlet
massflow
Inlet
enthalpy flux
Simulation and Validation
Input Data
Results
Institute of Technical Thermodynamics – Transient Modeling of the Lignite Power Plant “Jänschwalde”
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Simulation and Validation
Power Output
P Generator
P Generator Simulated
Institute of Technical Thermodynamics – Transient Modeling of the Lignite Power Plant “Jänschwalde”
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Simulation and Validation
Boiler Temperatures
Institute of Technical Thermodynamics – Transient Modeling of the Lignite Power Plant “Jänschwalde”
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Simulation and Validation
Preheater Temperatures
Institute of Technical Thermodynamics – Transient Modeling of the Lignite Power Plant “Jänschwalde”
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Simulation and Validation
Preheater Temperatures
Institute of Technical Thermodynamics – Transient Modeling of the Lignite Power Plant “Jänschwalde”
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Example Results
Fatigue in components for the reference scenario
Result
•
Fartigue for the components varies between
0,0008 and 0,0051 % for the reference
scenario
•
Evaporator and Superheater 2 are critical
components in dynamic operation
Conclusion
•
Fartigue of Headers
Same input scenario dones not lead to same
fatigue because of different temperatues and
different geometries
Outlook
Lastgradient
Load gradient Scenarios
2.5%, 4%, 6%
Gradmax
Pmin
operation parameters
Mindestlast
Min load scenarios
50%, 37.5%, 33%, 20 %
different operation modes
Simulation of critical load and wind scenarios under
variation of load gradient, min load of PP
Jänschwalde or operation of the power plant
in special mode
special operation modes
„shut down & restart“
„reduce to circulation mode“
Institute of Technical Thermodynamics – Effects of fluctuating Wind Power on Power plant operation
Stillstand
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Thank you for your attention!
Dipl.-Ing. M. Hübel
Dr.-Ing. J. Nocke
Prof. Dr.-Ing. E. Hassel
And thanks to our sponsors for financial support
Institute of Technical Thermodynamics – Dynamic Power Plant Simulation
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