impact of quality and quantity of fuel on achieving pat...

Impact of quality and quantity of fuel on achieving PAT targets

“Implementation of PAT Scheme in Thermal Power Stations – Issues and Challenges”

30.1.2015 India Habitat Centre, Lodhi Road, New Delhi

Dr. W.A.Benesch Director Energy Technolgies

Dr. Benesch 30.1.2015

PAT and power industry

• India’s PAT (Perform, Achieve, Trade) scheme provides a model to increase economic benefits with climate co-benefits

• The PAT scheme targets energy consumption reductions of 6.6 Mio t of oil equivalent in 478 covered facilities

• Plant specific targets are set instead of a sectorial target • The average reduction target is 4.8% • Power sector plays a dominant role

WE are STEAG. Our facts and figures

• WE are specialists in the generation of electricity and heat on the basis of a wide variety of technologies, and for the marketing of electricity and heat;

• with 9 hard coal fired and 2 refinery power plants in Germany, and 3 hard coal fired power plants in Colombia, Turkey and the Philippines;

• with more than 200 distributed generating facilities on the basis of renewable sources, for energy supply to industry and heat supply;

• with an installed capacity of 8,500 MW in Germany and 1,700 MW abroad;

• with a workforce of 3,700 in Germany and 2,300 abroad;

• with total sales of EUR 2.9 billion and EBITDA of EUR 366 million in 2013;

• with an investment volume of around EUR 363 million in 2013.

Dr.Benesch 30.1.2015

We do not have a PAT scheme in Germany but….

….. according to the rules of our electricity market we have to follow the merit order.

This means Highest efficiency and Lowest fuel price

And here we are connected to PAT Dr.Benesch 30.1.2015

Steag optimization experience with own power stations for more than 75 years

Bergkamen A 780 MW

Bergkamen Herne

Herne 2/3/4 960 MW

Bexbach Duisburg-Walsum

Iskenderun

Iskenderun 1/2 1,320 MW

Bexbach 1 780 MW Walsum 7/9/10 1350MW

Voerde A/B 1,522 MW West 1/2 712 MW Weiher 3 724 MW

Weiher Voerde

Mindanao Lünen Völklingen-Fenne Paipa

Lünen 6/7 507 MW Mindanao 1/2 232 MW Termopaipa IV 165 MW MKV, HKV, MHK *) 466 MW



How is coal affected by PAT?

PAT sets targets for improvements in energy efficiency in thermal power plants. At least efficiency of power plants is monitored and should be improved by this tool. How is coal now affected? • Coal quantity is an indicator for

efficiency

• Coal quality is essential for efficiency


Some issues

• With high grade coal of cause higher efficiencies could be reached easier, but what to do if these coals are not available?

• The PAT scheme sets plant specific targets. If the achieved efficiency of a power station should be benchmarked -the question could be raised- how far is the coal quality influencing this comparison?

• Main influencing parameters are ash, water and sulfur content, but to what extend?

• Coal quality is heavily influencing slagging and fouling which itself influences boiler efficiency.

• Combustion efficiency is governed by volatile matter content but also by the boiler design.

• Design coal and operating coal show very often great differences. Accordingly the design efficiency and the reached efficiency in day to day operation are different.

• Coal washing can influence quality, uniformity and quantity of fuel.

Mixed and unmixed coals?

When examining coal analyses, it has to be taken into consideration that one hardly ever has to do with one individual coal.

Even in case of coal from one mining area, the power station is frequently supplied with mixed sorts of coal from different coal pits or, if they come from one pit, from different seems.

Mixed sorts of coal as to their grinding and combustion qualities are basically different from one unmixed coal.

So it becomes very important to discuss the possibilities and restrictions of coal mixing.



What is poor coal

• High ash content

• Hardness

• High water content

• High sulfur content

• Non-uniform quality


Implications of poor coal quality

• Emissions environment

• Wear costs, availability

• Maintanance costs

• El. consumption PAT related

• Boiler efficiency PAT related

• Slagging and fouling PAT related

• Less power output overall capacity


How to achieve a benefit in the PAT scheme fuel related

• Control coal quality

• If possible buy an appropriate coal

• Consider washed coal

• Homogenize

Definitions dealing with mixing of coal

Homogenization Minimize fluctuations in coal properties Mixing Definite new coal qualities, but some elements of the original coals can still be detected Blending Definite new coal qualities

Quality of the process

In day to day operation with the existing equipment at the power stations, a homogenization other than a mixing or blending is usually possible.



Indirect effects of efficiency increase

Higher capacity Cost reduction Environmental friendliness


FGD / DENOX

Fuel gas condition:: - CO 2

- temperature

Steam parameters : - pressure - temperature

Reheater spray attemperator: - flow rate

Parasitic power consumption - auxiliaries load - exciter - equipment

firing: - O 2

- CO - after burning - leakage - NO X

Fuel - mass flow - Quality

Feedwater- preheating: - terminal temperature difference

condenser - terminal temperature difference - temperature

- boiler inlet temperature

Performance monitoring of power stations as part of the PAT scheme Online


Performance monitoring of power stations as part of the PAT scheme Offline with Mobile Measuring Vehicle

• Pulverized-coal measuring module • Fly ash measuring module • PC / fly ash analysing module

• Extensive gas analyzing module • Portable gas analyzing module • Calibration module for gas analyzers

• Temperature measuring module • Volume flow rates measuring

module • Measuring module for turbines

• Measuring module for pumps • Measuring module for condensers • Measuring-value data logging and

processing module

Performance monitoring of power stations as part of the PAT scheme Efficiency team

Formation of an “energy efficiency team” (3 to 4 people) Plant visits (2 weeks on site) document review and

discussions with the station personnel Creation of a database collecting the key information for the

regarded power station Check of the current coal quality and comparison with the

design coal Comparison of as built and theoretical boiler performance

based on acceptance tests Check of every load case of the boiler and the current

efficiency of the boiler Evaluation of the heat absorption in the different boiler parts

and the air preheater Monitoring of the auxiliary power consumption, the air

ingress, the milling system and the soot blowing system Evaluation of the turbine condition, main components of the

water steam cycle, the whole cold end and the related heat rate



Coal quality influencing the entire power plant

Grain sizeBulk densitySpecific weightGrindabilityWear characteristicPyrite contentSulphur contentSand contentWood contentSalt contentHeating valuesElementary analysisVolatile mattersWater contentAsh contentIgnition temperatureCompositionViscosityMelting qualityCementabilityWater contentAngle of slope

FuelParameters Coal

handlingCoalmills

Dust firingsystem

Steamgenerator

Ashhandling

Airpreheater

FDF IDF ESP FGD

Ash

Components

Coal

Availability and maintenance costs are governed by the parts being in contact with the coal - efficiency is part of the game -


Improper coal and influence on combustion system and boiler

• Bad or too late ignition

• Too early ignition

• Too long flames (touching the walls)

• Too high CO or NOx formation

• Wall corrosion

• Fouling problems

• Problems with bottom ash

• Limitation of part load and full load


Chlorine content of coals and influence on corrosion

Rel

ativ

e co

rros

ion

rate

Chlorine content in % (ar)

country

GB USA Australia Belgium India New Zeeland Poland South Africa

Chlorine content in % (ar)


Slagging and Fouling

• current coal • coal mixture • coal history • appropriate boiler design


Slagging and fouling indices


Example for unburnt carbon in filter ash for high grade coals depending on volatile matter content

0 5 1 0 1 5 2 0 2 5 3 0 3 50

5

1 0

1 5

2 0

2 5

Volatile matter content in % (waf)

Unb

urnt

car

bon

in a

sh in

%


Furnace Design Depending on Unit Capacity


"Treatment of new coal"

Offered Coal- Origin- Quantity

Special Conditions

- Spotmarket- Special fuel

Additional Test and Information- Theoretical- Laboritory- Fullscale test incinerations

BlendedUnblended

Known Quality

Data from- Coal data bank- Standard analysis

Check whether insideof range

of a STEAG power station(- Technical criteria)

Economical

TechnicalDecision

Blendedinsiderange

Incineration

Definition of aBlend

YesNoYes

No

Yes

No

Yes

RejectedNo

Rejected

No

Yes

Yes

No

Combustion

Coal washing can influence quality, uniformity and quantity of fuel

Advantages • Efficiency increase

• Reduced land consumption

• Saved transport capacity

• lower transportation costs

• less investment for boiler, fuel- and ashhandling

• lower maintenance costs due to lower erosion

Disadvantages • Investment in coal

washing plant

• operation costs


Coal washing yes or no

⇒ Typically coal washing is more economic than transportation and combustion of low grade coals

0

20

40

60

80

100

120

coalwashing

minemouth

100km 5000km

transportationoperating costsinvestment

0

20

40

60

80

100

120

coalwashing

minemouth

100km 5000km

transportationoperating costsinvestment

∆ ash 5% ∆ ash 20%


Benchmarking needs

• PAT is asking for high efficiency

• Coal quality is a major factor influencing efficiency

• Examples had been given how poor coal reduces efficiency

• Appropriate coal has to be chosen if possible

• Efficiency loss due to poor coal quality has always cost increase as a result

• If PAT should be successful the influencing parameters have to be made transparent

⇒ At least apples should not be compared with pears


Power generating cost

Operation Operation

Capital

Administration

Power generating cost

Administration

Capital

Energy Energy

•Pay level •Working hours •Regulatory requirements

•Unit number •Output •Operation mode •Coal type

•Organization •Workflows •External service material •Technology

Site Power plant type/ "Comparative use Gap“

Adjustments Power Plant 1 Power Plant 2

Benchmarking Example for necessary adjustments


Summary

Coal quality is influencing efficiency values

Typically coal quality can only be influenced limited

• Coal washing and

• Homogenization are of help

Proper benchmarking of heat consumption needs consideration of coal quality and quantity

Differences between design and really operated coal have to be considered

Choosing a certain coal quality many parts of the power plant are affected, technical and commercial aspects are heavily linked.

Every coal is black But not every black is coal


impact of quality and quantity of fuel on achieving pat...

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