Steag Group

Steag’s Long-Term C

Operating Experience a

2005 Workshop on Selective Catalytic 

Sponsored by EPRI

November 15 – 17, 2005

Louisville, Kentucky 
Steag Group

Operation & 

Maintenance

Power Generation 

and District Heating

Engineering and 

IT Solutions

Steag Group Facts:• Steag is a wholly owned subsidiary of 

largest bituminous coal mining compa

• Steag is Europe‘s second largest pow

bituminous coal.

• Steag owns and operates more than 1

and steam generating capacity.

• In 2004 Steag:

• had more than 5,000 employees w• had revenues of more than $ 6 bill• operated 28 electric generating un• had 3 electric generating units und• operated 9 waste-to-energy plants • operated 20 electric generating un

• For more info go to www.steag.com.
Steag‘s 

Power Plants

Fen500 

Germany Cologne-Godorf

215 MWel + eq.

Bergkamen750 MW

Bexbach775 MW

Voerde2,220 MW

Lünen500 MW

Wa600 750 CO

Leuna158 MWel + eq.

Termopaipa,Columbia165 MW

Mindanao,Philippines260 MWCOD 2005

International Iskenderun,

Turkey1.320 MW
Steag‘s 

SCR Arrangements

Steag’s Various SCR Arrangement

Boiler NH3

SCR

Air Heater

Air

ESP

FGD ESP

Air Air Heater

Regenerative GGas Heat Exch

Boiler

ESP

Air

Air Heater

Steam

NH3

SCR

Regenerative 

Gas-Gas Heat 

Exchanger 

Steam 

Reheater

Boiler

ESP 

FGD
Herne 

Cogeneration Plant

Herne Cogeneration Plant:- Units 1 & 2 - 150 MW electricity each.- Unit 3 - 300 MW electricity.- Both PC U-fired, wet bottom boilers.- Tail-end SCRs, honeycomb catalyst.- Unit 4 - 385 MW electricity.

- 550 MW district heat.

- PC wall-fired, dry bottom boiler.- High-dust SCR system, plate catalyst.- Bone meal, waste bituminous coal, 

ash > 40%, sulfur < 1.5%. 

- Wet CaO/CaCO3 forced oxidation 

FGD system producing wall board quality gypsum, flue gas reheat via rotary gas/gas heat exchanger.

- Operator: Steag- Owner: Steag- Power Purchaser: RWE

Steag District Heat 
Herne Unit 3

Tail-End SCR

0 20000 40000 60000 80000 10

SCR operating hours

DeNOx potential P

Herne 3

SCR Commissioning in 1988:- 1 1⁄2 layers of honeycomb catalyst (550 m- 2 1⁄2 spare layers (still empty).Operation during the past 110,000 operatinextremely uneventful. No catalyst addition Total catalyst replacement cost = 0.9% per 
Herne Unit 4

High-Dust SCR

0 20000 40000 60000 80000 

SCR operation hours

DeNOx potential P

Herne 4

SCR Commissioning in 1989:- 2 layers of honeycomb catalyst (installed - 2 spare layers (layers 2 and 4).Severe erosion problems resulting from wreplacement of both honeycomb layers in plate catalyst has been used. Operating h
4.2

4.1

3.2 D D D D 

C C C C 

HC 2 3.1

2.2 F (new) F 2.1 E (new) B G (new) 

1.2 B B

A E E 

HC 1 1.1

layer

0 (plate) 16,500 31,000 45,000 

Initial 

(hc)

A

Removal 

of honeycombs; 

addition 

of plate 

layers.

Addition 

of new

half plate 

layer E.

Removal of 

layer A to

regeneration, 

addition of 

new plate 

layer F.

Removal of 

layer B to

regeneration, 

addition of 

new plate 

layer G.

Removal o

layer C to

disposal, 

addition of 

new plate

layer H.

Herne Unit 4

High-Dust SCR

Herne 4 Catalyst Exchange Logbook
Comments and Costs:

- Honeycomb was found to be unable to w

from the high ash waste coal burned.

- Initial fill of 4 half plate layers was set to 

the initial cost. 

- Total catalyst exchange cost during the 

operating hours was found to be:

- For catalyst replacement 9 (4 initial a

new half layers (= 225% of initial cosreplacement layer (= 12% of initial co

- For field labor cost for the installatio

the removal of 5 half layers was founinitial catalyst cost = 110%.

- Total catalyst replacement costs = 347% 

cost per 1,000 operating hours.

-2-

Herne Unit 4

High-Dust SCR
Voerde 

Power Station

Voerde Power Station:- Units 1 & 2 – both 350 MW PC U-fired, w

- Waste bituminous coal, ash > 40%, sulfu- Both tail-end SCR systems, honeycomb - Units 3 & 4 – both 760 MW PC wall-fired, - World market bituminous 

coal, ash < 15%, 

sulfur < 1.5%.

- Both high-dust SCR 

systems, honeycomb and plate catalyst mixed.

- Wet CaCO3 forced oxidation 

FGD system producing wall board quality gypsum, no 

flue gas reheat, wet stack.

- Operator: Steag- Owner: Steag 75%

RWE 25%

- Power Purchaser: RWE
Voerde Unit 4

High-Dust SCR

0 20000 40000 60000 80000 

SCR operating hours

DeNOx potential P

Voerde 4

SCR Commissioning in 1989:- 3 layers of honeycomb catalyst (installed - 1 spare layer (layer 4).LPA catalyst pluggage problems appeared 1996. After installation of Steag’s LPA scrproblems with LPA intrusion into the SCR 
Voerde Unit 4

High-Dust SCR

Voerde 4 Catalyst Exchange Logbook

4.24.1

B 

3.2 C (hc) C C B (reg) 

3.1

A 

2.2 B (hc) B A (reg) A 2.1

1.2 E E C (reg) 

D (pl) D A (hc) 1.1

layer

40,000 48,000 49,000 75,000 

Initial 

0

D

Removal of layer A 

(plugged) to 

regeneration, addition 

of regenerated plates 

from Herne 4 and new

plate layers D and E.

Removal of 

layer B to

regeneration, 

addition of 

regenerated 

layer A.

Removal of 

layer C to

regeneration, 

addition of 

regenerated 

layer B.

Removal 

layers D, E 

regenerati

addition o

regenerat

layer C.

E (pl)
Voerde Unit 4

High-Dust SCR

Comments and Costs:- Initial fill of 3 honeycomb layers was set 

of the initial cost.

- Total catalyst exchange cost during the 

operating hours was found to be:

- For catalyst replacement 5 (3 initial, 

honeycomb replacement) new layers cost) plus 4 regenerated honeycomb (= 66% of initial cost).

- For field labor cost for the removal a

layers was found to be 6 x 10% of in60%.

- Total catalyst replacement costs = 293% 

cost per 1,000 operating hours.

- Note that 2 catalyst exchanges were cau

pluggage and not by normal catalyst de
Walsum 

Cogeneration Plant

Walsum Cogeneration Plant:- Unit 7 - 150 MW PC U-fired, wet bottom b

- Low dust SCR system, honeycomb catal- Unit 9 - 450 MW PC tangentially-fired, dry - High dust SCR system, plate catalyst. - Bituminous waste coal, 

ash > 40%, sulfur < 1.5% plus sewage sludge.

- Wet CaO/CaCO3 forced

oxidation FGD systems producing wall board. quality gypsum, flue gas 

reheat via gas/gas reheater.

- Operator: Steag- Owner: Steag- Power Purchaser: RWE

EnBW
Walsum Unit 9

High-Dust SCR

0 20000 40000 60000 80000 100000 12

SCR operation hours

DeNOx potential P

Walsum 9

SCR Commissioning in 1988:- 4 half layers of plate catalyst (installed in - 2 spare half layers (layer 1).Severe erosion resulting from the very hig40%) of the waste coal burned demanded catalyst from initial commissioning on. Ha
Walsum Unit 9

High-Dust SCR

Walsum 9 Catalyst Exchange Logbook

3.2 D D D D D 

3.1 C C C C C 2.2 B B B B B 2.1 A A A A A 

1.2 G (used) H (used) H J (new) 1.1 I (new) I 

layer

31,700 51,500 83,500 96,700 

Initial

0

G

Addition 

of used 

layer G 

from 

Walsum 

Unit 7.

Addition 

of used 

layer H 

from 

Walsum 

Unit 7.

Removal of 

layer G to

regeneration, 

addition of 

new layer I.

Removal of 

layer H to

regeneration, 

addition of 

new layer J.

Removal o

layers C an

D to disposa

addition of 

regenerated 

layer H and 

new layer K 
Walsum Unit 9

High-Dust SCR

Comments and Costs:- Initial fill of 4 half plate layers was set to 

the initial cost. 

- Total catalyst exchange cost during the 

operating hours was found to be:

- For catalyst replacement 7 (4 initial a

new half layers (= 175% of initial cosadditional layers (= 25% of initial cosregenerated replacement layer (= 25

- For field labor cost for the installatio

the removal of 5 half layers was founinitial catalyst cost = 120%.

- Total catalyst replacement costs = 345% 

cost per 1,000 operating hours.
Weiher 

Power Station

Weiher Power Station- 710 MW PC wall-fired, drybottom boiler. - Saar regional bituminous 

coal, ash < 15%, sulfur < 1.5%.

- High-dust SCR system, 

honeycomb catalyst.

- Wet CaCO3 forced oxidation 

FGD system producing wall board quality gypsum, no reheat, flue gas discharge via cooling tower

- Operator: Steag- Owner: Steag- Power Purchaser: RWE
Weiher Unit 3

High-Dust SCR

Weiher Power Station Unit 3

- 10,000 20,000 30,000 40,000 50,000 

SCR operating hours

DeNOx potential P 

Weiher 3 

SCR Commissioning in 1990:- 3 layers of honeycomb catalyst (installed - 1 spare layer (layer 4).Coal switch from Weiher coal to Bexbach regional mines) caused formation of stronlayers due to high CaO content in the fly a
Weiher Unit 3

High-Dust SCR

Weiher 3 Catalyst Exchange Logbook

4.2 D (new) D D D (reg) D 

4.13.2 C A (reg) A A E (new) 

3.1

B 2.2 B C (reg) C C 

2.11.2 A B (reg) B 

1.1

layer

26,631 32,868 36,681 42,627 45,853 

Addition 

of new

honeycomb 

layer D.

Removal of 

layers A, C to 

regeneration, 

addition of 

regenerated 

layer A.

Removal of 

layer B to

regeneration, 

addition of 

regenerated 

layer C.

Addition of 

regenerated 

layer B, 

regeneration 

of layer D.

Removal 

layer A t

regenerat

addition 

new hone

comb laye
Weiher Unit 3

High-Dust SCR

-2-

Comments and Costs:- Initial fill of 3 honeycomb layers was set 

of the initial cost.

- Total catalyst exchange cost during the 

operating hours was found to be:

- For catalyst replacement 5 (3 initial a

new layers (= 167% of initial cost) plreplacement layers (= 67% of initial c

- For field labor cost for the removal o

of 9 layers was found to be 17 x 10% cost = 170%.

- Total catalyst replacement costs = 404% 

cost per 1,000 operating hours.

- Note that after the switch to Bexbach co

deactivation rate increased significantly formations of strong surface blinding la
Leuna

Cogeneration Plant

Leuna Refinery Cogeneration Plant- Units 1 – 3 combined:

- 178 MW electricity (total).- 208 MW process steam (total).- All liquid/slurry wall-fired, dry bottom bo- Pet coke and refinery 

residues, ash < 5%, sulfur > 3.5%.

- High-dust SCR systems, 

plate catalyst.

- Wet lime forced oxidation 

FGD systems producing wall board quality gypsum, flue gas reheat via steam coil.

- Operator: Steag- Owner: Steag- Power Purchaser: Total 

Fina ELF Refinery
Leuna

Cogeneration Plant

Leuna Units 1, 2 and 3

- 10,000 20,000 30,000 40,000 

SCR operating hours

DeNOx potential P 

P U1 P U2 P U3

SCR Commissioning in 1996/97:- 2 layers of plate catalyst (installed in laye- 1 spare layer (layer 3).Deactivation highly dependent on fuel comcomposition highly variable. Honeycomb deactivated very rapidly. Since then only 

Leuna 1, 2 and 3 
Leuna

Cogeneration Plant

Leuna 1, 2 and 3 Catalyst Exchange Logbook

hours 0 30,178 32,813 33,994 37,772 40,470 54

A A E (reg) E E E B B B B B D (reg) D C G (new) G G G A (reg) D D D F (reg) F F 

E E C (reg) C C C 

F F H (new) H H H 

out for regen. C F A A, B B 

G used 

U3U2U1

Removal of 

layer C to

regeneration, 

purchase of

a new honeycomb layer 

G.

Removal of 

layers A, E, F 

to

regeneration, 

purchase of a 

new plate 

layer H, 

addition of 

regenerated 

layers E, C.

Removal of 

layer D to

regeneration, 

addition of 

regenerated 

layer F.

Removal of 

layer G, 

addition of 

regenerated 

layer A.

Removal of lay

regeneration, 

regenerated la

Remo

laye

addit

regen

laye
Leuna

Cogeneration Plant

Comments and Costs:- Initial fill of 6 plate layers (2 per unit) wa

100% of the initial cost.

- Total catalyst exchange cost during the 

operating hours for all 3 units was found 

- For catalyst replacement 8 (6 initial a

new layers (= 133% of initial cost) plreplacement layers (= 83% of initial c

- For field labor cost for the removal o

of 13 layers was found to be 26 x 10cost = 260%.

- Total catalyst replacement for costs all 3 

2.27% of initial cost per 1,000 operating 

- Note that honeycomb catalyst was foun

more rapidly than plate catalyst. It was rplate catalyst, regenerated and used els
Summary and 

Conclusions

Summary and Conclusions:

Specific Catalyst Cos

0123456

Herne 3 Herne 4 Voerde 4 Walsum 9 

% per 1,000 h 

Specific catalyst cost vary highly depend- The SCR arrangement – tail-end approx

high-dust despite extensive use of rege

- The fuel – high ash (i.e. waste coal) vers

PRB) versus high vanadium (i.e. Pet cok
Summary and 

Conclusions

Summary and Conclusions:- Catalyst is viewed and treated by Steag 

however not all catalyst types are suitabapplications. 

- Each type of catalyst has its distinct adv

disadvantages. The selection of the besrequires an economic evaluation on a ca

- The use of new versus regenerated cata

on market conditions and prices. The prcatalyst varied between 25% and 65% of depending on the price of new catalyst aregeneration process used and required

- Steag found no difference in longevity o

between regenerated and new catalyst. SO2/SO3 conversion rate may differ sign

on the regeneration process used.
Steag

?Questions?

Steag‘s SCR 

experience: 

~ 2 million hours 

of SCR operation