German Experience 

Catalyst Regenera

Hans Hartenstein

STEAG LLC 

2007 NOx Round Table an

February 5 – 6, 2007

Cincinnati, Ohio

STEAG
SCR Catalyst Regeneration Nomenc

● Cleaning = Removal of physical re

blinding layers and largcan be done on-site as 

● Rejuvenation = Removal of catalyst po

need for replenishing ccompounds – can somsitu, but is most commdone either on-site or o

● Regeneration = Removal of catalyst po

restoration of catalytic addition of catalytically – can typically not be dsite, but should be donrequired close process 

Nomenclature

STEAG‘s Bergkamen 

Power Station

STEAG‘s Fenne 

Cogeneration Plant
SCR Catalyst Regeneration History

● 1983: Legislation – Flat rate NOx emissio

mg/Nm

3 (~100 ppm) for all units 

≥ 

regardless of age, fuel and capacit

● Mid to late 1980’s: SCRS were installed o

fuel fired units in Germany to mee

requirements

● Mid to late 1990’s: 

• Catalyst deactivation by plugging 

poisons became a greater concern market coal and “secondary fuels” 

• Buying new catalyst was economi

light of deregulation and increasin

• Several utilities including EnBW, H

began R&D on catalyst cleaning a

Key Events

STEAG‘s Bexbach 

Power Station

STEAG’s Weiher 

Power Station
SCR Catalyst Regeneration History

● 1995/1996: STEAG starts developing an 

for LPA removal after Voerdeand 4 have major LPA problehoneycomb layers plug as a from indigenous to world ma

● 1996/1997: SBW (now STEAG) develops 

process for the removal of sulayers and rejuvenation after Göttelborn to Ensdorf coal (caused the formation of strolayers at Bexbach’s 780 MW 725 MW Unit 3 due to high Caash (similar to PRB) .

● 1996/1997: EnBW develops a simple in-s

removal of ordinary fly ash prejuvenation at the Power Pla

Key Events

EnBW‘s Heilbronn 

Power Station

STEAG’s Voerde 

Power Station
SCR Catalyst Regeneration History

● 1997/1998: SBW/STEAG perform first ful

rejuvenations at Bexbach anblinding layers and mild catacleaning at Voerde (removal 

● 1997: STEAG’s Leuna Cogeneratio

100% refinery residue includup with all 3 units having higrely on regeneration for sustainable SCR operation.

● 1997/1998: HEW develops an on-site pro

of ordinary fly ash pluggage 

the Tiefstack Cogeneration P

● 1998/1999: Integral develops an on-site c

rejuvenation process at a coa

for the removal of vanadium unit) and mild catalyst poison

Key Events

HEW‘s Tiefstack 

Cogeneration Plant
SCR Catalyst Regeneration Process

● BHK Process:

• On-site process, which was used onc

Generating Station for one layer of B

• Process seems to be no longer mark

no other known applications in Europ

● EnBW’s In-situ Rejuvenation Process:

• Process was further refined and optim

overcoming its limitations of being pwhich is also its main advantage.

• Still used in house within the EnBW/E• Technology sold to CESI/SCR-Tech f

America and to Envica/EKS for use e

● Envirgy Process:

• Spun off of Integral in late 2002.

• Developed a cleaning process in 200

Enerfab who markets the process in 

Regneration 

Processes

EnBW‘s In-situ 

Rejuvenation Process
SCR Catalyst Regeneration Process

● HEW Process:

• HEW and SAS founded KAS to furthe

market the HEW process for cleaningregeneration.

• HEW sold its 50% share in KAS, (rena

later EKS) now markets the technoloNorth America where it was sold to C

● Integral Process:

• Process is being successfully marke

Europe and Asia after further proces

● KWH Process:

• KWH developed a regeneration proce• Process was used a few times in Ger

have disappeared from the market wimove of KWH to China.

Regneration 

Processes

HEW‘s On-site 

Rejuvenation Process

Integral‘s On-site 

Rejuvenation Process
SCR Catalyst Regeneration Process

● STEAG/SBW Process:

• Steag acquired SBW and obtained a 

Umwelttechnik GmbH, Austria for STfor North America.

• Merged technologies, know-how and 

development of a significantly optimi

• Used up to now for in house rejuvena

regeneration only.

• On-site process for cleaning and reju

• Off-site process for cleaning, rejuven

regeneration.

• Marketed in North America exclusive

late 2006. 

• STEAG’s off-site regeneration facility 

operation in Kings Mountain, North C2007.

Regneration 

Processes

LPA Plugged Catalyst 

– STEAG‘s Voerde 

Power Station

Rejuvenated Catalyst 

– STEAG‘s Voerde 

Power Station
STEAG’s Catalyst Regeneration Nee

● STEAG developed a regeneration proces

• Perpetually frequent need for 

• Ca-based blinding layer removal a

the Bexbach, Fenne and Weiher c

• Rejuvenation of V-based blinding 

reduction of SO

2/SO

3 conversion 

of the Leuna and Godorf refinery fuel, high-dust SCRs).

• A more cost effective process for odd 

• Bexbach (9 x 18 log honeycomb m• Fenne (24 box triple-decker plate • Weiher (6 x 6 log honeycomb mo

• Rapidly growing regeneration needs 

fleet of currently 24 (soon 26) SCRs use of world market coals and seco(sewage sludge, bone meal, pet cok

Regeneration 

Needs

Weiher 6 x 6 Log 

Honeycomb Modules

Fenne 

Triple-decker Plate 

Modules
Bexbach, Weiher and Fenne – Blind

● A coal switch to Ensdorf coal 

caused rapid deactivation due to unknown causes at the time.

● The formation of a very strong 

surface blinding layer mostly consisting of CaSO

4 and fly ash was fou

● Ensdorf coal with a CaO content in the fly 

10%wt. was determined to be the source

● A patented, DI-water based rejuvenation 

developed and has been successfully aplayers at Bexbach, Fenne and Weiher sin

● Since then the same catalyst layers have 

rejuvenated up to 3 times.

STEAG’s Bexbach 

Power Station

STEAG’s Weiher 

Power Station

Blinding Layers

- 10,000 20,

DeNOx potential P 
Addition 

of new 

honeycomb 

layer D.

Removal of 

layers A, C to 

regeneration, 

addition of 

regenerated 

layer A.

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

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 

Removal of 

layer B to 

regeneration, 

addition of 

regenerated 

layer C.

Addition of 

regenerated 

layer B, 

regeneration 

of layer D.

Removal o

layer A to 

regeneratio

addition o

new honey

comb layer 

Bexbach, Weiher and Fenne – Blind

STEAG’s Weiher 

Power Station

Regenerated Weiher 

6 x 6 Log Honeycomb 

Modules

Regeneration 

Experience
STEAG’s Catalyst Regeneration Exp

● STEAG’s regeneration process developm

• Need for higher activity gains than po

rejuvenation only.

• More than 2 – 3 rejuvenations are not 

the incremental gain in activity declineconomic threshold. Full regeneratio

Regeneration 

Experience

Rejuvenation Tank at 

Weiher Power Station

Rejuvenation Bexbach Layer C

0

1020304050

0 10,000 20,000 30,000 

activity [m/h]

layer C operating hours

Rejuvenation Tank 

During Catalyst 

Loading
Leuna and Godorf – Vanadium Pore 

● High-dust SCR in combination

with the refinery residue fuel(S 

≤ 6%wt.) highly problematic.

● Very rapid deactivation at times, 

highly dependent on fuel mix. 

● The formation of a very strong pore plug

consisting of vanadium and fly ash as wdepending on fuel composition was foun

● Unit operation would be 

uneconomical without catalyst regeneration due to highly variable catalyst exchange frequencies and cost.

Leuna 

Cogeneration Plant

- 10,000 2

DeNOx potential P 

P U1 

STEAG’s Leuna 

Cogeneration Plant

STEAG’s Godorf 

Cogeneration Plant 

out for regen.

C F A 

F F H (new)

H

E

E C (reg)

C

U3

D

D

D F (reg

C G (new)

G

G

U2

B

B

B

B 

A

A E (reg)

E

U1

hours 0 30,178 32,813 33,99

out for regen.

C F A 

F F H (new)

H

E

E C (reg)

C

U3

D

D

D F (reg

C G (new)

G

G

U2

B

B

B

B 

A

A E (reg)

E

U1

hours 0 30,178 32,813 33,99
STEAG’s Catalyst Regeneration Exp

● STEAG’s regeneration process developm

• Suspicions of increases in SO

2/SO

3 c

when regenerated by commercial reg

Regeneration 

Experience

Bergkamen Vendor Regeneration Ho

0%

50%

100%150%200%

K0 Kreg KSO2/

STEAG‘s Bergkamen 

Power Station

STEAG‘s Bergkamen 

Power Station
STEAG’s Catalyst Regeneration Exp

● Further investigation confirmed the prob

• Other utilities reported similar observ• Unwanted and/or unpredictable incre

considered very undesirable for STEA

Voerde Vendor Regeneration Hone

0%

50%

100%150%200%250%300%350%

K0 Kbefore reg Kreg KSO2/SO30 

Regeneration 

Experience

STEAG’s Voerde 

Power Station

STEAG’s Voerde 

Power Station
STEAG’s Catalyst Regeneration Exp

● STEAG’s regeneration process was benc

commercial regenerators in Europe:

• R&D was focused on getting the SO

2/

rate under control while regaining ful

Regeneration 

Experience

Comparative Testing Vendor Process Vers

0%

50%

100%150%200%250%

K0 Kbefore reg Kreg KSO2/SO3

STEAGVendor

Before Treatment

During Treatment
STEAG‘s Patented Regeneration Te

● STEAG’s patented regeneration technolo

effective:

• Removal of physical restrictions (fly a

• Removal of catalyst poisons (As, P, N

• Protection of components essential fo

catalyst’s structural integrity and mec(i.e. WO

3).

• Full activity restoration through reple

catalyst’s active components (V

2

O

5, M

• Recalcination for best impregnation s

mechanical strength protection. 

Catalyst 

Regeneration

Receiving / Warehouse 

Dry and/or Wet Cleaning 

Chemical Treatment 

Ultrasonic Treatment 

Ion Mobilization and Elimination 

Preconditioning for Impregnation 

Selective Catalytic Impregnation 

Drying and Recalcination 

QA/QC Inspection 

Packaging / Warehouse / Delivery 

STEAG’s Catalyst 

Regeneration 

Process
STEAG’s Patented Processes (continu

● Developed patented processes that are f

• Dry and/or wet mechanical cleaning (• Multi-stage wet chemical treatment fo• Ultrasonic cleaning (only if needed an

• Ion mobilization, elimination and prec

impregnation.

• Selective replenishment of V

2

O

5, MoO

needed (in case of full regeneration o

• Multi-stage drying.• Recalcination (only in case of regene• Repair of mechanical (e.g. erosion) d• Packaging.

Catalyst 

Regeneration

STEAG’s Catalyst 

Regeneration 

Process

Receiving / Warehouse 

Dry and/or Wet Cleaning 

Chemical Treatment 

Ultrasonic Treatment 

Ion Mobilization and Elimination 

Preconditioning for Impregnation 

Selective Catalytic Impregnation 

Drying and Recalcination 

QA/QC Inspection 

Packaging / Warehouse / Delivery 
STEAG’s Catalyst Regeneration

● Technology based:

• Experience and own know-how devel

● STEAG’s own patents (German and U.S.)

• Use of DI-water for cleaning, rejuvena

regeneration.

• Aeration of vat during treatment.• Reduction of SO

2/SO

3 conversion rate

• Selectively distributive replenishmen

active ingredients.

● STEAG owns a license for the process de

Integral Umwelttechnik, Austria including patents for STEAG’s own SCR fleet and i

Catalyst 

Regeneration

STEAG’s Catalyst 

Regeneration 

Process

STEAG’s Patents 

for Catalyst 

Regeneration
STEAG‘s Regeneration Experience

● Experience gained and regeneration perf

was tested and verified within our own palmost 10,000 m

3 of SCR catalyst.

• 3,220 m

3 for STEAG’s SCR fleet in Ge

• Single layers regenerated up to 4 tim• 680 m

3 for various third parties in Eu

● Some of STEAG’s SCRs depend and sole

successful catalyst regeneration for adeqoperation and economical unit operationand Godorf Cogeneration Plants. 

Catalyst 

Regeneration

STEAG’s Patents 

for Catalyst 

Regeneration
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 best requires 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

● As other German utilities, STEAG also fo

in longevity or deactivation rate between new catalyst. However, the SO2/SO3 conv

significantly, depending on the regenera

STEAG’s Herne

Cogeneration Plant

STEAG’s Walsum

Cogeneration Plant
STEAG’s catalyst 

regeneration: 

10 years of 

in-house 

experience

?Questions?

STEAG