Flue Gas Mercury Removal Using Carbon-

Polymer Composite Material

X. Sean Lu, Zach Xu, Steve Stark, Richard Gebert, W.L. Gore & Associates, Inc.

Tom Machalek, Carl Richardson, Jennifer Paradis, URS Corporation

Ramsay Chang, Electric Power Research Institute

Brandon Looney, Marcus Mathews, Southern Company

EUEC

January 31 – February 2, 2011, Phoenix, AZ

W. L. Gore &

Associates

Outline

• Introduction

• Lab tests

• Field demonstrations

• Summary

W. L. Gore &

Associates

Introduction

• Activated carbon for flue gas Hg removal:

– Carbon injection: low Hg capacity, fly ash contamination

– Stationary carbon bed: saturation by SOx or other acid gases, frequent bed regenerations

• Gore’s carbon-polymer composite (CPC) tape material:

– Activated carbon (chemically treated) and fluoropolymer composite tapes

– Applied in stationary bed configurations

– Much less potential to be saturated by SOx or other acid gases, therefore, no frequent bed regenerations are required

W. L. Gore &

Associates

Introduction

• Gore’s carbon-polymer composite (CPC) material (continued):

– Flue gas conditions: low temperature ( < 100oC) and humid ( > 50%RH)

– SOx and other acid gases are converted into aqueous acid solutions and expelled to the CPC tape’s outer surfaces, then collected

– Hg can be fixed on the carbon surfaces with high capacity ( > 1.0wt%) due to the low operating temperatures; therefore, long-term operation before sorbent saturation by mercury

– CPC tapes can be made into modular forms with reasonably low pressure drop

– US patent: 7,442,352 B2 (2008) by Lu & Wu

W. L. Gore &

Associates

Introduction

Regeneration

mode

Adsorption

modeBy high temp

heating

Or by water

washing

A system to collect

& treat SOx

A system to treat

dilute H2SO4

solution, < 2% acidAcid

Solution

Carbon column

Flue gas

SOx, Hg Clean air

Typical Stationary Carbon Bed Applications

W. L. Gore &

Associates

Lab Tests

• SOx and Hg removal - convert SOx into sulfuric acid solution

W. L. Gore &

Associates

Lab Tests

• SOx and Hg removal - convert SOx into sulfuric acid solution

(continued)

0

20

40

60

80

100

0 5 10 15 20 25 30 35

Time (day)

SO

2 R

emoval

Eff

icie

ncy

(%

)

Regular carbon

CPC tape

0

20

40

60

80

100

0 5 10 15 20 25 30 35

Time (day)

SO

2 R

emoval

Eff

icie

ncy

(%

)

Regular carbonRegular carbon

CPC tape

Test conditions:

• 900ppm SO2

• 6mg/m^3 Hg

• 4cmx7cm tape

• 300sccm flow

• 65C

• 65% RH

W. L. Gore &

Associates

Lab Tests

• SOx and Hg removal (continued) – High mercury removal

efficiency & capacity

Test Condition: 200sccm, 6mg/m^3, 65%RH, 67C, 1.8 gram sample

0

10

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0 20 40 60 80 100 120 140

Time (hour)

Hg

Rem

oval E

ffic

ien

cy

(%)

Test Conditions: 900ppm SO2, 6.0mg/m^3 Hg, 65%RH, 65C

W. L. Gore &

Associates

Lab Tests

• Mercury removal with parallel plate

arrangement – by URS

– Mercury: 20-50 mg/m^3

– SO2: 50 ppmv

– Temperature: 140F (60C)

– RH: 50%

– Gas flow: 0.8cfm

– Total CPC tape: 3.8” x 23” (two strips)

Flow In

Flow Out

Plastic back

Gore CPC

tape

¼”

W. L. Gore &

Associates

Lab Tests

• Mercury removal with parallel plate by URS (continued)– URS model simulations: Stabilized Hg removal efficiency = 80%

Stabilized Hg removal Eff. = 82%

W. L. Gore &

Associates

Lab Tests

• Mercury removal with parallel plate by URS (continued) -

Distribution of Hg on CPC tape after URS testing

Hg content on carbon tape after URS BT test

0

100

200

300

400

500

600

0 5 10 15 20 25

Distance from Inlet (inch)

Merc

ury

Co

nte

nt

on

Tap

e (

pp

mw

) Tape-2 Tape-1

W. L. Gore &

Associates

Small scale field demonstrations

• Plant Yates Demonstration (I) – Parallel Plate (March – July

2010)

– The demonstrations were jointly carried out by Gore, EPRI, URS,

and Southern Company

– Tests were done at Southern Company’s Plant Yates power station

– Slip stream flue gas was taken after limestone wet scrubber (from

stack)

• Temperature: ~123F (51C)

• Humidity: 100%

• Flow Rate: 5.0cftm (5ft/second linear velocity)

• Carbon tape: 4-strips of 5in x 5ft

• Testing date: March 26, April 21, May 20, July 13, and July 30, 2010

W. L. Gore &

Associates

Plant Yates – Newnan, Georgia

W. L. Gore &

Associates

Small scale field demonstrations (continued)

We are

here!

W. L. Gore &

Associates

Small scale field demonstrations (continued)

CPC

tapesStack

Floor

Tent

Adjustable valve

Analytical

equipments

Inlet

portOutlet

port Venturi

meter

Blower

W. L. Gore &

Associates

Small scale field demonstrations (continued)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 20 40 60 80 100 120

Test Period (Days of Operation)

Perc

en

t R

em

oval (%

)

Total Hg Removal - 5acfm, 10ft

SOx Removal

Temperature Excursion

Hg & SO2

Removal

?

W. L. Gore &

Associates

Small scale field demonstrations (continued)

W. L. Gore &

Associates

Small scale field demonstrations (continued)

• Plant Yates Demonstration (II) – Sorbent Module (Aug. -

present)

– The demonstrations were jointly carried out by Gore, EPRI, URS,

and Sothern Company

– Tests were done at Southern Company’s Plant Yates power station

– Slip stream flue gas was taken after limestone wet scrubber (from

stack)

• Temperature: ~123F (51C)

• Humidity: 100%

• Flow Rate: 13.0 and 24.7acfm (5 and 9.5ft/second linear velocities)

• Carbon tape: 6” deep, 3.8” diameter cylindrical modules (8 modules)

• Testing date: July 31, Aug. 30, Sept 16, Oct 26, Nov. 29

W. L. Gore &

Associates

Small scale field demonstrations (continued)

Six Modules

Eight Modules

Sampling

Ports

Liquid Collector/Drain

Flue Gas Inlet

CPC Tape module

W. L. Gore &

Associates

Small scale field demonstrations (continued)

4" Diameter CPC Roll Pressure Loss - roll inside PVC pipe

0.0

0.2

0.4

0.6

0.8

1.0

0 100 200 300 400 500 600

Velocity, fpm

Pre

ssu

re D

rop

, in

ch

H2O

Lab Data

Field Data

W. L. Gore &

Associates

Small scale field demonstrations (continued)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 20 40 60 80 100 120 140

Operation Time (Days)

Me

rcu

ry R

em

ov

al

Total Hg Removal - SixModules

Total Hg Removal - EightModules

Plant Outage

System Offline

Hg Removal

W. L. Gore &

Associates

Small scale field demonstrations (continued)

0

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60

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80

90

100

Three-modules Six Modules Eight Modules

Merc

ury

Rem

oval (%

)

Linear Gas Velocity - 5.0ft/s

Linear Gas Velocity - 9.6ft/s

W. L. Gore &

Associates

Small scale field demonstrations (continued)

SO2

Removal

0

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30

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50

60

70

80

90

100

0 20 40 60 80 100 120 140

Operating Time (day)

SO

2 R

em

ova

l E

ffic

ien

cy (

%)

SO2 Removal - six modules

SO2 Removal - eifht moduleseight modules

W. L. Gore &

Associates

Summary

• A unique sorbent material, carbon polymer composite material (CPC), has

been developed for flue gas mercury and other contaminates removal

• The CPC material is deployed in a stationary sorbent bed applications, and

the sorbent bed does not require a frequent regeneration process

• Field demonstration tests have shown that the CPC bed is effective for

Hg/SOx removal (in coal-fired power plant after a wet scrubber) for long-term

(4-5 months without requiring frequent regeneration or maintenance

processes)

• We will perform a preliminary engineering economic analysis is to assess the

feasibility of retrofitting the CPC to the existing power plant and cost, and

conduct a medium scale field demonstration this year, and a full-scale field

demonstration afterward