Selective catalytic reduction (SCR)

has long been a common means to

reduce NOx emissions from industrial

power generation equipment.

However, concerns over the safety

and potential liability of anhydrous

ammonia used as a SCR reagent are

growing. Likewise, the costs

associated with aqueous ammonia

have driven many power generators

to look for additional alternate means

of reducing NOx.

The Fuel Tech NOxOUT SCR process

delivers a safer and simpler method of

operation. 

The Problem with Ammonia

Both anhydrous and aqueous

ammonia present operational and

handling problems when used as an

SCR reagent. Anhydrous NH3 typically

requires substantial tankage, relief

valves, heated vaporizer, and other

features. Aqueous ammonia typically

requires heating to evaporate the

water. Many systems are equipped

with a fan and ammonia injection grid

(AIG) to distribute dilute ammonia to

the catalyst surface.

Transportation of ammonia on public

highways is generally considered a

safety hazard. Storage vessels are

often required to be fitted with special

containment and safety features. 

Fire and safety concerns require

evacuation procedures and

emergency training. Evacuation plans,

public notification, and special permits

may be required by government

authorities.

Combustion

Zone

In-Duct 

Catalyst Reactor

Furnace

NOxOUT®

Reagent

Figure 1: The NOxOUT SCR Process

X

p

alternative to NH3 SCR for industrial generators.

NOx Reduction Process

TECHNICAL BENEFITS 

■ Up to 85% NOx reductions

■ Eliminates anhydrous 

ammonia and aqueous

ammonia handling and

storage requirements

■ Safer reagents require less

support equipment

■ No fouling

■ Eliminates RMP hassle

TECHNICAL BENEFITS 

■ Up to 85% NOx reductions

■ Eliminates anhydrous 

ammonia and aqueous

ammonia handling and

storage requirements

■ Safer reagents require less

support equipment

■ No fouling

■ Eliminates RMP hassle
The NOxOUT SCR Solution

NOxOUT SCR is an advanced form of

selective catalytic reduction (SCR)

system. Unlike the conventional SCR,

NOxOUT SCR incorporates a safe,

easy-to-use reagent. The safe

alternative reagent liberates ammonia

which reacts with NOx on the catalyst

surface. A simple injection system is

designed to ensure “clean” injection

with high conversion to NH3. NOxOUT

SCR provides high levels of NOx

control, similar to the conventional

SCR.

No Fouling

Typical operation of the NOxOUT SCR

process yields no buildup or fouling of

catalyst surfaces. Injectors stay clean,

and there is often no increase in

generator back pressure or decrease

in generator performance or

efficiency.

In all respects, NOxOUT SCR offers

the same NOx reduction performance

of an SCR system using anhydrous or

aqueous ammonia, without the

downside risks and catalyst build-up.

Figure 6: Transportation classification data 

NOxOUT Reagent vs. NH3

For more information on NOx reduction programs 

available from Fuel Tech, call, fax, or write us at:

Fuel Tech, Inc. • 512 Kingsland Drive • Batavia, IL 60510

Phone 800.666.9688 • 630.845.4500 • Fax 630.845.4501

www.fueltechnv.com • webmaster@fueltechnv.com

NOxOUT and NOxOUT SCR are registered trademark of Fuel Tech, Inc.

0

0

Area Velocity

NOxOUT® SCR Performance Parameters

Ammonia Slip as a Percent of Injected Chemical

NOxOUT Reduction

NH3/NOx Ratio

Ammonia Slip

Percent NO

x Reduction

10

20

30

40

50

60

70

80

90

100

0%

8%

15%

22%

30%

38%

45%

52%

60%

67%

75%

10 20 30

1.0

0.9

1.8

0.7

0.6

1 0

0

3 0

1

NOxOUT REAGENT AMMONIA

FT-9116-AP © 1999 Fuel Tech, Inc.

Figure 3-4: A large capacity turbo-diesel 

with a retrofit twin bed catalyst system. Figure 5:NOxOUT SCR provides flexible performance with a safe reagent

HEALTH HAZARD

4 - Deadly

3 - Extreme Danger

2 - Hazardous

1 - Slightly Hazardous

0 - Normal Material

SPECIFIC HAZARD

Oxidizer OXY

Acid ACID

Alkali ALK

Corrosive COR

Use NO WATER W

Radiation Hazard

FIRE HAZARD

Flash Points °F

4 - Below 73

3 - Below 100

2 - Below 200

1 - Above 200

0 - Will Not Burn

REACTIVITY

4 - May detonate

3 - Shock/heat may detonate

2 - Violent chemical change

1 - Unstable if heated