FTIR Monitoring of: NOx, SOx, SO3, & H2SO4

Environmental Controls Conference Pittsburgh, PA

May 16-18, 2006

Attempts to Monitor SO3/H2SO4 in Ducts

An FTIR system was used to monitor NO, NOAn FTIR system was used to monitor NO, NO22, , SOSO22, SO, SO33, H, H22SOSO44, H, H22O, CO, COO, CO, CO22, and , and HClHCl in SCR in SCR outputsoutputsThe FTIR either extracted a sample from the duct The FTIR either extracted a sample from the duct at high temperature (>200C) or performed at high temperature (>200C) or performed measurements inmeasurements in--situsituBoth approaches proved successful but the Both approaches proved successful but the extractive measurements had many problems extractive measurements had many problems getting the sample to the analyzergetting the sample to the analyzer

Attempts to Monitor SO3/H2SO4 in Ducts

Initial attempts used an extractive approach with Initial attempts used an extractive approach with high temperature (200C) lines and cellhigh temperature (200C) lines and cellLab tests showed both Lab tests showed both SO3 and H2SO4 could be monitored using Teflon lines at this temperatureLine effects were severe and limited length of line Line effects were severe and limited length of line that could be usedthat could be usedWith sufficient lineWith sufficient line passivationpassivation this approach was this approach was ultimately successfulultimately successful

Extractive MonitoringExtractive MonitoringLab TestsLab Tests

Imacc FTIR Base Unit with 10 meter cell Accessory

Imacc FTIR Base Unit with 10 meter cell Accessory

Imacc 10 meter cell Accessory

FTIR

Exhaust

Input from stack or ambient air

Detector

Pump

Typical Extractive FTIR System

Control andReductionComputer

Heated or ambientextraction line

Multi-passWhite Cell60cm-200mpath

Spectra of H2SO4 and SO3

H2SO4 Lab Test Setup

X

X

ConstantTemperature H2SO4 Bath

Pump

FTIR CellAmbient Air

Input

Heat Trace Line

Rotometer

Exhaust

Heated Teflon Line

Flow & Temperature Effects: H2SO4 Bath, 80 ft. Line

0

5

10

15

20

25

30

8:00 9:00 10:00 11:00 12:00 13:00

Time

H2S

O4

(ppm

)

15 scfh

30 scfh

15 scfh

7.5 scfh

96% H2SO4 76% H2SO4

T = 90 C

120 C,

25 scfhT = 90 C

Zero Flow

Flow & Temperature Effects: SO3 Bath, 80 ft. Line

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

8:00 9:00 10:00 11:00 12:00 13:00

Time

SO3

(ppm

)

96% H2SO4 76% H2SO4

T = 90 C

25 scfh

120 C, Predicted < 1 ppm

15 scfh

30 scfh

15 scfh

7.5 scfh

Comparison of H2SO4 Reference & Data SpectraFri Sep 27 10:44:43 2002

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Abs

817ppm H2SO4 22.1m/650/185C

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Abs

1080110011201140116011801200122012401260Wavenumbers (cm-1)

Comparison of H2SO4 Reference & Data SpectraFri Sep 27 10:44:43 2002

0.05

0.10

0.15

0.20

0.25

0.30

Abs

817ppm H2SO4 22.1m/650/185C

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Abs

800820840860880900920 940 Wavenumbers (cm-1)

Comparison of SO2 & SO3 Reference & Data Spectra

Fri Sep 27 10:44:43 2002

0.046

0.048

0.050

0.052

Abs

SO3 7897.3 ppm 0.2m/760T/25C

-0.00

0.01

0.02

0.03

Abs

SO2 800 ppm 5.2m/650t/185C Synthetic

-0.00

0.01

0.02

0.03

Abs

242024402460248025002520Wavenumbers (cm-1)

Extractive MonitoringExtractive Monitoringin SCR Outputsin SCR Outputs

H2SO4 & SO3 Line Equilibration With Overnight Run

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2

4

6

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10

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16

22:00 23:00 0:00 1:00 2:00 3:00 4:00 5:00Time

H2S

O4

- S

O3

(ppm

)

H2SO4

SO3

Observed Concentrations in SCR Output

Compound Concentration (ppm)

Water 60,000 Carbon Dioxide 114,000 Carbon Monoxide 2.1 to 2.4 Nitric Oxide 330 to 350 Nitrogen Dioxide 1.7 to 1.9 Sulfur Dioxide 2330 to 2370 Sulfuric Acid 36.3 to 37.5 Hydrochloric Acid 31.1 to 32.2

0

10000

20000

30000

40000

50000

60000

70000

80000

18:00 18:15 18:30 18:45 19:00 19:15 19:30 19:45 20:00 20:15 20:30Time

H2O

(ppm

)

3 Sigma Error

Observed H2O Concentrations in SCR Output

Observed CO2 Concentrations in SCR Output

0

20000

40000

60000

80000

100000

120000

140000

18:00 18:15 18:30 18:45 19:00 19:15 19:30 19:45 20:00 20:15 20:30

Time

CO

2 (p

pm)

3 Sigma Error

0

1

2

3

4

5

6

7

18:00 18:15 18:30 18:45 19:00 19:15 19:30 19:45 20:00 20:15 20:30

Time

CO (p

pm)

3 Sigma Error

Observed CO Concentrations in SCR Output

0

50

100

150

200

250

300

350

400

450

500

18:00 18:15 18:30 18:45 19:00 19:15 19:30 19:45 20:00 20:15 20:30

Time

NO

(ppm

)

3 Sigma Error

Observed NO Concentrations in SCR Output

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

18:00 18:15 18:30 18:45 19:00 19:15 19:30 19:45 20:00 20:15 20:30

Time

NO

2 (p

pm)

3 Sigma Error

Observed Concentrations in SCR Output

0

500

1000

1500

2000

2500

3000

18:00 18:15 18:30 18:45 19:00 19:15 19:30 19:45 20:00 20:15 20:30

Time

SO

2 (p

pm)

3 Sigma Error

Observed SO2 Concentrations in SCR Output

0

5

10

15

20

25

30

35

40

18:00 18:15 18:30 18:45 19:00 19:15 19:30 19:45 20:00 20:15 20:30

Time

HCl (

ppm

)

3 Sigma Error

Observed HCl Concentrations in SCR Output

0

10

20

30

40

50

60

70

18:00 18:15 18:30 18:45 19:00 19:15 19:30 19:45 20:00 20:15 20:30

Time

H2SO

4 (p

p

3 Sigma Error

Observed H2SO4 Concentrations in SCR Output

EPRI ProgramEPRI ProgramInIn--situ situ MonitoringMonitoring

EPRI In-situ Measurement Program

InIn--situ situ measurements are preferred for SOmeasurements are preferred for SO33/H/H22SOSO44because no contact with the sample is requiredbecause no contact with the sample is requiredHowever, particulate loading in ducts is very high However, particulate loading in ducts is very high limiting optical paths possible to a few incheslimiting optical paths possible to a few inchesEPRI contracted with Univ. of California at EPRI contracted with Univ. of California at Riverside to develop an inRiverside to develop an in--situ situ probe which would probe which would discriminate against particulatesdiscriminate against particulatesTests to date indicate the probe can reduce Tests to date indicate the probe can reduce particulate loading by 80% or moreparticulate loading by 80% or moreThis allowed for measurements over 30 to 60 ft. in This allowed for measurements over 30 to 60 ft. in ducts ducts -- path lengths that are normally impossiblepath lengths that are normally impossible

EPRI In-situ Measurement Configuration

ConfigurationConfigurationImacc CrossImacc Cross--stack unit coupled to instack unit coupled to in--situ situ probeprobeFTIR spectra analyzed for:FTIR spectra analyzed for:SOSO33, H, H22SOSO44, SO, SO22,, HClHCl, NH, NH33, CO, CO, CO, CO22, , NO, NONO, NO22, and H, and H22OOSystem initially set up for System initially set up for monostatic monostatic transmission measurements doubling the transmission measurements doubling the available pathavailable path

Imacc Monostatic Cross-Stack Unit

Laser Control

FTIR Modulator

Collimating TelescopeMirror

On-Board Computer

To Duct &Corner Cube

Array

PowerSupply

Imacc FTIR Base Unit

BeamSplitter

Mercury Cadmium Telluride Detector

Off-Axis ParabolicDetector Mirror

Spherical focusing mirrorImacc Custom Accessory

2.5” Corner Cube Mirror < 5 arc second accuracy

FTIR, Periscope, and Probe

Periscope, and Probe

Cross-stack Probe Installation

Curvature of Probe

Source Used for Bistatic Configuration

Spectra of Transmitted Infrared Source (Blue) Compared to The Background Radiance from The Probe Wall (Red)

Transmission Data

Probe RadianceStrong at Long WavelengthOr Small Wavenumber

EPRI Program - Measured FTIR Data and References

EPRI Program - Measured FTIR Data and References

EPRI Program - Measured FTIR Data and References

EPRI Program EPRI Program -- Gas Concentration DataGas Concentration Data

SpeciesSpecies MeasurementMeasurement((ppmvppmv))

Std DevStd Devof of

ConcentrationsConcentrations((ppmvppmv))

Detection LimitsDetection LimitsSingle TraverseSingle Traverse

((ppmvppmv))

SOSO33 16.916.9 4.04.0 ~ 3~ 3

HH22SOSO44 22.222.2 5.05.0 ~ 4~ 4

NHNH33 2.92.9 0.60.6 < 1< 1

NONO22 7.77.7 0.90.9 ~ 2~ 2

NONO 65.865.8 4.34.3 ~ 5~ 5

HClHCl 4.14.1 0.40.4 < 1< 1

EPRI Program EPRI Program -- Gas Concentration DataGas Concentration Data

EPRI Program - Gas Concentration Data

Controlled CondensateControlled CondensateDataData

EPRI Program - Intercomparison Data

Controlled Condensate H2SO4 SO3 Total10/25/05

Concentration 33.61 25.98 11.35 37.33St. Dev. 3.15 5.7 2.3 6.2

10/26/05Concentration 32.00 24.30 13.36 37.66St. Dev. 3.4 5.4 3.5 6.4

FTIR

EPRI Phase IIEPRI Phase IIProgramProgram

EPRI Program EPRI Program –– Phase IIPhase II

Next phase to be conducted at Next phase to be conducted at AmerenAmeren’’ss Sioux Sioux StationStation near St. Louisnear St. LouisProbe now supported in slip fittings allowing for Probe now supported in slip fittings allowing for free expansion but no horizontal movementfree expansion but no horizontal movementDuct width 32 ft. should provide an optical path of Duct width 32 ft. should provide an optical path of 64 ft (19.5 m).64 ft (19.5 m).Primary objective: long term unmanned operation Primary objective: long term unmanned operation

for assessment of maintenance issuesfor assessment of maintenance issuesTest to be 1 month long with option for a second Test to be 1 month long with option for a second monthmonth

EPRI Program EPRI Program –– Phase IIPhase II