Keys to Success: SCR Installat

at Dominions Brayton Point 

Units 1 and 3

Brian Wright 

– Dominion New England

Clayton Erickson 

– Babcock Power

Matthew Phillipo 

– Babcock Power

Electric Power

May 2008
Agenda

• Background Data• Scope of Supply• SCR Design Parameters – Performa• SCR Design Parameters – Site Issu• Startup and Commissioning• Performance Test Results
Background Data

Unit 1: 250 MW 

C.E., balanced draft boiler, firing low sulfur compliant coal (0.98%)

SCR Design:

Reduce NOx by 90%Aqueous Ammonia 

(19% ammonia in water)
Scope of Supply

Unit 1

• One 2+1 layer reactor• Cormetech honeycomb – 7.0 mm pitch ca• Aqueous Ammonia System with direct am

injection

• Seven injectors per reactor – Delta wing 

technology

• Sonic Horns – 6 per layer• Economizer Bypass – for low load• Structural Steel and platforms• Construction• Catalyst and Air Heater Hoist System
Cross Section

CO

UNIT 1 

CROS

VENV
Background Data

Unit 3: 650 MW 

B & W opposed fired, balanced draft boiler, firing low sulfur compliant coal (0.98%) 

SCR Design:

Reduce NOx by 90% 

Aqueous ammonia reagent
SCR Reactor System

Unit 3

• Two identical 2+1 layer reactors• Cormetech honeycomb – 7.0 mm pitch ca• Aqueous Ammonia System with direct am

injection

• Four injectors per reactor – delta wing mi

technology

• Sonic Horns – 6 per layer• Economizer Bypass – for low load• Structural Steel and Platforms• Construction• Catalyst and Air Heater Hoist System
Cross Section

0 BabcockPower 

ENVIRONMENTAL 

SCR ARRANGEMENT 

UNIT3 

BRAYTON POINT 
Design Parameters –

Performance for Both Units

Parameter Value NO

x Removal Efficiency >90% 

Based on Inlet NOx = 0.40 lb/

NH3 Slip <2 ppm at end of catalyst 

16,000 hrs 

SO

2 to SO

3 conversion rate <1.0%, initial layers of c

installed 

NH

3/NO

x Distribution 5% rms 

Flue Gas Inlet Temperature Distribution 

Over 100% surface: +/-27°F 
SCR Design Parameters 

Site Issues

• No loads to existing building steel on Unit • Extensive reinforcement of boiler steel on • Short distance between Economizer Outl

Airheater

• Derrick crane on roof of Unit 3 for Unit 3 a

future Unit 2 construction

• Column locations required relocation of e

plant facilities (column in Men’s Room)
Site Issues - Design

• No loads to existing building steel on • Unit 1 existing internal steel work mo
Site Issues - Design

• Short distance 

between Economizer Outlet and Airheater
Site Issues -

Construction

• Derrick crane on roof at Unit 3
Site Issues -

Construction

• Main steel required office space relo
Startup and 

Commissioning Unit 1

• Requirement for fast startup and 

commissioning 

• Schedule

Day 1: Initial calibration and baseline testingDay 2: Installation of NH3 supply system soDay 3: Mixing performance metDay 4: Performance confirmed and removal 

efficiency met, ready for acceptance Unit in automatic
Performance – Test 

Results Unit 1

-9

οF Min

+5

οF Max

+/-27

οF

ο Temperature Variation 

F

Upstream of the 1st catalyst 

layer

SO2 to SO3 Conversion Rate 

%

<1.0 0.05 

with Initial Catalyst (total conversion)

Ammonia Slip at 3% O2 ppmv

<2.0 0.08 

NH3/NOx variation % rms 5.0 2.35 

NOx Removal Efficiency Rate

% >90 91.1 

(

Full Load 

(260 MWgross)

Parameter Guarantee
Startup and 

Commissioning Unit 3

• Requirement for fast startup and 

commissioning 

• Schedule

Day 1: Initial calibration and instrument setuDay 2: Initial NH3 injection, tuned Reactor 3

mixing performance met

Day 3: Tuned Reactor 32, mixing performanDay 4: NOx removal performance met, read

acceptance testing, Unit in automatic
Performance – Test 

Results Unit 3

Full Load (640 Mwgross)

-2

οF Min

+3

οF Max

+/-27

οF

ο Temperature Variation 

F

Upstream of the 1st catalyst 

layer

SO2 to SO3 Conversion Rate 

%

<1.0 0.24 

with Initial Catalyst (total conversion)

Ammonia Slip at 3% O2 ppmv

<2.0 0.07 

NH3/NOx variation % rms 5.0 1.0 

NOx Removal Efficiency Rate

% >90 91.5 

Parameter Guarantee Reactor 31 
Conclusion

• Difficult site conditions to overcome• Construction completed on time• All outage schedules met• Startup and commissioning within

– 4 days Unit 1– 4 days Unit 3

• All guarantees and schedules met• OTAG Season 2007, both units 0.04 

lbs/Mbtu – Long term performance