improvement of flexibility of coal fired power plants
TRANSCRIPT
Confidential. Not to be copied, distributed, or reproduced without prior approval.
Improvement of Flexibility of Coal Fired Power Plants 08 June 2017
Confidential. Not to be copied, distributed, or reproduced without prior approval.
Energy systems in transition – Europe and Germany
08 June 2017 2 Improvement of Flexibility of Coal Fired Power Plants
Europe: - Reduction of greenhouse gas emissions in 2020 compared with 1990:
20% (2013: 19%) / 2030: 40% - Total energy consumption from renewable energy in 2020:
20% (2014: 15,3%) / 2030: 27%
Germany: - Overall target is reduction of greenhouse gas emissions until 2020 by 40% (2015:
27%) and until 2050 by more than 80 % ‒ (ref. year: 1990) - Installed generation capacity (net) is about 186 GW with ~26% installed capacity
based on coal fired power plants. Renewable installed generation capacity (net) is ~98 GW with ~84 GW wind and solar
- The target of gross power supply by renewable sources in 2020: 35% (2015: 30%) / 2050: 80%
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Power generation and consumption in Germany
08 June 2017 3 Improvement of Flexibility of Coal Fired Power Plants
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Conventional power generation in Germany
08 June 2017 4
NEW challenges/requirements for coal fired Power Plants
Improvement of Flexibility of Coal Fired Power Plants
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Requirements for coal fired power plants
08 June 2017 5
Lower technical min load Shorter start-up time Faster load changes More load cycles
Wider fuel ranges Alternative fuels
Increasing demands due to the changing in the energy market
high availability reliable power production
low emissions environmental friendly
high efficiency low impact on ressources
easy to service economical
flexible compliance with grid code
The conventional Power Plants need to cope with the increased requirements
Improvement of Flexibility of Coal Fired Power Plants
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Increase of Flexibility
08 June 2017 6
Flexibility More load Cycles
Lower techn.
min. Load
Improvement of Flexibility of Coal Fired Power Plants
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State of the Art – What is feasible?
08 June 2017 7
State of the Art
new power plants : 25% existing power plants : 40%
conventional firing 15 - 20% indirect firing 10% - 15%
minimum load hard coal
number of load cycles moderate high / very high
load jumps (primary control)
2% / 30s (german grid requirement) up to 5% / 30s feasible up to 10% / 10s
(secondary control) load ramps ca. 2-5% / min up to 10% / min
biomass 100% biomass 10% co-combustion
Further development (new and existing power plants)
1-4 hours depending on start-up conditions Start-up time 2-6 hours
depending on start-up conditions
minimum load lignite
conventional firing 35 - 40% indirect firing 10% - 15%
new power plants : 40% existing power plants : 50%
Improvement of Flexibility of Coal Fired Power Plants
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Optimization of conventional coal fired power plants – Flexible power plants
08 June 2017 8
Process Optimization
Optimization Pressure Parts and Materials
Implementation of indirect firing system
Optimization of Equipment
Verringerung der Wellenleistung (Eigenbarf) am Beispiel eines Primärlüfters (Radialventilator)
Wellenleistung mit DrallreglerWellenleistung mit Frequenzumrichter
Förderarbeit der Ventilatoren
Wel
lenl
eist
ung
(Eig
enbe
darf)
der
Ven
tilat
oren
Verbesserung des Teillastwirkungsgrades am Beispiel eines Primärlüfters (Radialventilator)
Förderarbeit der VentilatorenW
irkun
gsgr
ad d
er V
entil
ator
en
Wirkungsgrad mit DrallreglerWirkungsgrad mit Frequenzumrichter
Schalldämpfer
Improvement of Flexibility of Coal Fired Power Plants
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Optimization of bituminous coal fired power plants
08 June 2017 9
Reduction of minimum load by means of process and plant optimization full load operation: 4 mills
minimum load new power plants: 25% existing power plants: 40%
minimum load today: 2 mills
minimum load new and existing power plants: 15% - 20%
minimum load after optimization: 1 mill
Improvement of Flexibility of Coal Fired Power Plants
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Optimization of bituminous coal fired power plants – Load range extension for bituminous coal
08 June 2017 10 Boiler load in %
2 mills in operation
1 mill in operation
3 mills in operation
initial load range
4 mills in operation
decreased minimum load
Reduction of minimum load by means of process and plant optimization
Improvement of Flexibility of Coal Fired Power Plants
Confidential. Not to be copied, distributed, or reproduced without prior approval.
Optimization of bituminous coal fired power plants – 2 mills operation to 1 mill operation
08 June 2017 11
Reduction of minimum load by means of process and plant optimization
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[mg/m³]
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350[°C]
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14:00 15:00 16:00 17:00 18:00 19:00Time
Flue gas temperature before DeNOX [°C]
Fuel stream to the mill 2 [kg/s]
Fuel stream to the mill 3 [kg/s]
[%];[kg/s]
Firing thermal capacity [%]
NOX after DeNOX correct [mg/m³]
1 Mill in operation2 Mills in operation
Improvement of Flexibility of Coal Fired Power Plants
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Optimization of lignite fired power plants
08 June 2017 12
Reduction of minimum load by means of process and plant optimization Full load: 6 - 7 mills
Minimum load New power plants: 40% Existing power plants: 50%
Minimum load today: 4 mills
Minimum load New and existing power plants: 35% - 40%
Minimum load after optimization: 3 mills
Reduction of minimum load by means of process and plant optimization
Improvement of Flexibility of Coal Fired Power Plants
Confidential. Not to be copied, distributed, or reproduced without prior approval.
Optimization of lignite fired power plants – Load range extension for lignite
08 June 2017 13
Reduction of minimum load by means of process and plant optimization
Boiler load in %
7 mills in operation
6 mills in operation
5 mills in operation
4 mills in operation
decreased minimum load
Increased load range (higher flexibility)
initial load range
3 mills in operation
Reduction of minimum load by means of process- and plant optimization
Improvement of Flexibility of Coal Fired Power Plants
Confidential. Not to be copied, distributed, or reproduced without prior approval.
Indirect firing system for hard coal – Comparison with conventional firing system
08 June 2017 14
conventional (direct) firing: mill burner
Improvement of Flexibility of Coal Fired Power Plants
Confidential. Not to be copied, distributed, or reproduced without prior approval.
Indirect firing system for hard coal – Comparison with conventional firing system
08 June 2017 15
conventional (direct) firing: mill burner (partial-) indirect firing: mill separator / bunker burner
Improvement of Flexibility of Coal Fired Power Plants
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Indirect firing system for lignite – Partial indirect firing (direct supply)
08 June 2017 16
combustion air
Pulverized coal bunker
Conveyor system
Pulverized coal duct Secondary air
Dry lignite / conveying air
Core air
Swirling device
wall opening
Ignitor
Main burner
Burner for dry lignite
Burner arrangement
Indirect firing: bunker burner
Improvement of Flexibility of Coal Fired Power Plants
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Indirect Firing System – Reduction of dynamic response delay
08 June 2017 17
Reduction of dynamic response delay (secondary control)
• Grinding process causes delays due to storage capacity of mill
• Separation of grinding and storage
• Significant reduction of system response time
Significant Improvement in Dynamic Response Time
Fast Load Changes
Improvement of Flexibility of Coal Fired Power Plants
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Indirect firing sytem for lignite – References: dry lignite firing
08 June 2017 18
OxPP (PP Schwarze Pumpe): 1 x 30 MWth, dry lignite
Silo dry lignite Burner for dry lignite Improvement of Flexibility of Coal Fired Power Plants
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Indirect firing sytem for lignite – References: dry lignite firing
08 June 2017 19
Ignition- and supplementary firing In operation since 2003
Niederaußem-K: 8 x 90 MWth
Niederaußem-K: burner for dry lignite
Niederaußem-K: silo pulverized coal Improvement of Flexibility of Coal Fired Power Plants
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Optimized firing systems – Hard coal & lignite
08 June 2017 20 Boiler load in %
Optimized direct firing lignite
Optimized direct firing hard coal
Indirect firing hard coal & lignite
Reduction of minimum load
Improvement of Flexibility of Coal Fired Power Plants
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Conclusions
08 June 2017 21
• The phase out from using nuclear energy and the increasing power production from wind and solar energy determine increased requirements for conventional power plants.
• Reliable power production therefore requires extended transmission and storage capacity as well as flexible and high efficient power plants to provide the strongly fluctuating residual load.
• The key developments of conventional fired power plants are as follows:
- Minimum load reduction - Reduction of start-up time - Flexibilisation of load operation (faster load changes
and more load cycles) and - Reduction of emission for full load range.
Improvement of Flexibility of Coal Fired Power Plants
