september 13-14, 2012 | santa ana, california · september 13-14, 2012 | santa ana, california ftir...

CEMTEK ENVIRONMENTAL’S CEMTEK ENVIRONMENTAL’S

2012 EMISSIONS MONITORING SEMINAR & TRAINING SESSION2012 EMISSIONS MONITORING SEMINAR & TRAINING SESSIONSeptember 13-14, 2012 | Santa Ana, Californiap |

FTIR Systems & OperationFTIR Systems & Operation

INDUSTRIAL MONITOR AND CONTROL CORP.

CEMTEK ENVIRONMENTAL’S 2012 EMISSIONS MONITORING SEMINAR & TRAINING SESSION

Basic Concepts of Basic Concepts of Optical Optical DetectionDetection


Active & Passive Open Path FTIRActive & Passive Open Path FTIRActive & Passive Open Path FTIRActive & Passive Open Path FTIR

• Active transmission mode uses a light source in the• Active transmission mode uses a light source in the FTIR which is modulated by the instrument and is then transmitted through the gas to be monitored.

• The transmitted beam is captured and analyzed to determine the compounds present and their

t ticoncentrations.

• Analysis is done using reference standards for each compound collected under controlled conditions of:compound collected under controlled conditions of: concentration, temperature, pressure, and path length


Typical Extractive FTIR SystemTypical Extractive FTIR System

DetectorControl and

Reduction

FTIRComputer

Input from stack or ambient air

Multi‐passWhite Cell60 20060cm‐200mpath

ExhaustHeated or ambientextraction line


Pump

Basic ConceptsBasic Conceptspp

Most molecules absorb infrared (IR) lightMost molecules absorb infrared (IR) light- The patterns of IR wavelengths (colors) they absorb are

unique to each molecule- The amount of light they absorb is proportional to

their concentration

As a Result:

- The presence of specific compounds can be unequivocallydetermined by the absorption patterns

As a Result:

- The concentration of the compounds can be measured by thestrength of the absorption patterns


Infrared Absorbance Spectra of Select CompoundsInfrared Absorbance Spectra of Select Compounds


What About OverlappingWhat About OverlappingFeatures?Features?Features?Features?


Infrared Absorbance Spectra of Select CompoundsInfrared Absorbance Spectra of Select Compounds

Overlapped Spectra


Overlapped Spectra of NOOverlapped Spectra of NO22 and NHand NH33


Wh t C AWh t C AWhat Can An What Can An FTIR MonitorFTIR Monitor

Measure ?Measure ?


Compounds CoveredCompounds Coveredpp

• The FTIR can monitor most molecular species• The FTIR can monitor most molecular species except for homonuclear diatomics (Cl2, H2, O2, N2, etc.) 2, )

• The detection limit varies by compound but allThe detection limit varies by compound but all can be detected to sub ppm-levels with small systems and to the low ppb-level with larger systems


Detection Limits Detection Limits


Basic EquationsBasic EquationsT i i M dT i i M dTransmission ModeTransmission Mode


Transmittance of an Absorption CellTransmittance of an Absorption Cell

Absorption CellIo ( ) I( )

Absorption Cell

0%= {I

=( )( )

100%= {Io=( )

( )


Transmittance for MoleculesTransmittance for Molecules

) I( )/I ( )) = I()/Io() C L= e ‐ C L

Where:

k(n) = the gas absorption coefficient

C th t tiC = the gas concentration

L = The optical path length


Transmittance for Molecules (cont.)Transmittance for Molecules (cont.)

{ t ( ) }Absorbance = - log10 { t (n) }

= ‐ log10 {e ‐ C L}

= (0.434) C L

Scales as concentration times path length


Scales as concentration times path length

Transmittance Spectrum of HCNTransmittance Spectrum of HCN


Absorbance Spectrum of HCNAbsorbance Spectrum of HCN


Measured Spectra of Phenol at Various ConcentrationsMeasured Spectra of Phenol at Various Concentrations


The The Fourier Fourier Transform Transform Infrared SystemInfrared System

(FTIR)(FTIR)(FTIR) (FTIR)


Schematic of FTIR ModulatorSchematic of FTIR Modulator

Fi d Mi

Moving Mirror

Fixed Mirror

CollimatingMirror

BeamBeamsplitter

Waveform Addition

Aperture

Focusing


FocusingMirror IR

Source

Typical FTIR Typical FTIR InterferogramInterferogram Near Center BurstNear Center Burst


InterferogramInterferogram & Absorbance Spectrum From FTIR& Absorbance Spectrum From FTIR


The FTIR ProcessingThe FTIR ProcessingSequenceSequence


FTIR Processing Sequence FTIR Processing Sequence


B i C t fB i C t fBasic Concepts of Basic Concepts of FTIRFTIR AnalysisAnalysisFTIR FTIR AnalysisAnalysis

------Cl i l L t SCl i l L t SClassical Least SquaresClassical Least Squares


Linear Least Linear Least SquaresSquares Regions and Regions and ComponentsComponents

Region

743 50 I S I743.50 I ‐ S ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ I ‐ ‐ ‐

766.25 I ‐ I ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ S ‐ ‐ ‐ ‐ ‐ ‐

889.50 I ‐ ‐ I ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ S ‐ ‐ ‐ ‐ ‐ ‐ ‐

937 50 S I S S S S937.50 S ‐ I S ‐ S S ‐ ‐ ‐ ‐ S ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐

1009.00 I ‐ ‐ I ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ S ‐ ‐ ‐

1035.50 I ‐ I I ‐ ‐ ‐ ‐ S S S ‐ ‐ ‐ ‐ ‐ I ‐ ‐ ‐

1095.00 I ‐ ‐ I ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ S ‐ ‐ ‐ ‐ ‐1095.00 I I S

1148.00 I ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ S

1900.00 I ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ S ‐

2138.50 I S I ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐

2207.50 I I I ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ S ‐ ‐

2787.00 I ‐ ‐ ‐ I ‐ ‐ S I ‐ ‐ ‐ ‐ ‐ ‐ S ‐ ‐ ‐ ‐

2932.50 I ‐ ‐ ‐ S ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐


Observed SpectrumObserved SpectrumHouston, Texas 15 April 1991Houston, Texas 15 April 1991

Sample Clean Air

0.3

0.35

0.25

0.3

0.2

0.25

0.15

0.2

0.25

rban

ce

0 05

0.1

0.15

0.05

0.1

Abs

o

l

0

0.05

860 872 884 896 908 920 932 944 957 969 981 993-0.05

0


0.5 cm‐1 resolution Wavenumber (cm-1)

Observed SpectrumObserved SpectrumHouston, Texas 15 April 1991Houston, Texas 15 April 1991, p, p

0.35

Sample Clean Air

0.25

0.3

0 2

0.25

0.3

e

0.15

0.2

0.1

0.15

0.2

Abs

orba

nce

0.05

0.1

0

0.05

A

0 5 cm‐1 resolution

0860 872 884 896 908 920 932 944 957 969 981 993

-0.05

Wavenumber (cm-1)


0.5 cm 1 resolution

Difference SpectrumDifference SpectrumReference File OverlaysReference File Overlays

Data C3H6 Isobut CO2

Reference File OverlaysReference File Overlays

0.1

0.12

0.1

0.12

0.06

0.08

orba

nce

0.06

0.08

0.02

0.04Abs

o

0

0.02

0.04

l

0860.37 884.47 908.57 932.67 956.77 980.87

Wavenumber (cm 1)

-0.02

0






0.1

0.12

0.1

0.12

0.06

0.08

orba

nce

0.06

0.08

0.02

0.04Abs

o

0

0.02

0.04

0860.37 884.47 908.57 932.67 956.77 980.87

Wavenumber (cm 1)

-0.02

0






0.1

0.12

0.1

0.12

0.06

0.08

orba

nce

0 04

0.06

0.08

0.02

0.04Abs

o

0

0.02

0.04

0 5 cm‐1 resolution

0860.37 884.47 908.57 932.67 956.77 980.87

Wavenumber (cm-1)

-0.02


0.5 cm 1 resolution Wavenumber (cm-1)




0.1

0.12

0.1

0.12

0.06

0.08

orba

nce

0 04

0.06

0.08

0.02

0.04Abs

o

0

0.02

0.04

0860.37 884.47 908.57 932.67 956.77 980.87

Wavenumber (cm-1)

-0.02


0.5 cm‐1 resolutionWavenumber (cm 1)

The The ImaccImacc FTIR FTIR MonitorsMonitors


The Base UnitThe Base Unit

The unit utilizes a 0.125 cm-1 “dash-pot” interferometer with “dynamic alignment” both of which provide stabilitywith “dynamic alignment” both of which provide stability critical for field work

– The “dash pot” consists of a graphite piston running in a precision glass tube, it has only one degree of freedom and as a result is very stable and immune to vibration

– The “dynamic alignment” is laser controlled and actively aligns the FTIR thousands of times per second providing additionaltimes per second providing additional immunity to vibration and temperature variations


Base Unit AccessoriesBase Unit Accessories

• The modular arrangement allows use of both cell• The modular arrangement allows use of both cell-based and open-path accessories with one base unit

• The cell-based accessories are used for extractiveThe cell based accessories are used for extractivemonitoring in: ambient air, industrial process streams, stacks, or abatement systems

• The telescope-based accessories are used for open-path monitoring in: the ambient air, at the fence-line, or around process areasor around process areas


Cell Based AccessoriesCell Based Accessories

The cell-based accessories use heated cells and extraction lines at temperatures up to 200°C, allowing for monitoring of saturated process streams (hot/wet).

Typical cell accessories include: Typical cell accessories include:– Fixed path cells: 5 cm and 10 cm (% concentrations)– Variable path cellsVariable path cells

1 m to 10 m cell (0.1 ppm)4 m to 32 m cell (20 to 50 ppb)12 m to 80 m cell (3 to 10 ppb)24 m to 150 m cell (1-5 ppb)


Shell CellShell Cell--Based MonitorBased Monitor


InteriorInterior of Shell System


LowerLower--LevelLevel FTIR ModulatorFTIR Modulator


UpperUpper--Level Cell and DetectorLevel Cell and Detector


Passive FTIR OperationPassive FTIR Operation


Passive FTIR RadiometerPassive FTIR Radiometer


Passive OpenPassive Open--Path SignaturesPath Signatures

• Any hot gas emits infrared with exactly the same y g ypattern that it has in absorption

Th f i i i i t b• Therefore species in emission spectra can be identified and quantitated in the same manner as they are in absorption spectroscopy

• However

• The strength of emission is proportional to concentration as it is in absorption spectra but also to the temperature of the gas


to the temperature of the gas.

Hardware - Passive FTIR At Flare Test


The Signal Observedg

BackgroundRadiance

FlareRadiance The FTIR Signal arises from Four elements:

•The Total FTIR Signal M is then:

AtmosphericTransmission& Radiance

•Background radiance•Flare radiance•Atmospheric Transmission and Radiance

The Total FTIR Signal Mp is then:Rb * plume atm + Rp * atm + Ratm + Rftir

The FTIR signal can be reduced to:( ) C lM M( )

)(p b

pnb

pairbb

Cal

CalM MR M M

L

Mp = The measured plume radianceMb = The measured background radianceMn = The measured cold source backgroundLpbb = The Planck function at temperature of plumeCal = The system calibration function


Cal = The system calibration functionair = Air Transmission

Flare Efficiency

1

y

0.995

%)

Moderate Over

0.985

0.99

ffici

ency

(%

Heavier OverSteaming

Moderate Over Steaming

0 975

0.98

Ef Steaming

0.97

0.975

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


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

Extractive Probe Used in TCEQ Flare Validation Test


CE vs. CZG NHV - All TCEQ Steam

100%

70%

80%

90%

y (%

)

50%

60%

ion Efficiency

TCEQ 20:80 TNG to Propylene (S3 S4 S5 S6)

20%

30%

40%

Combu

sti TCEQ 20:80 TNG to Propylene (S3,S4,S5,S6)

TCEQ 20:80 TNG to Propylene (S7,S8,S9,S10,S11)

TCEQ 100% Propane (S12,S13,S14)

0%

10%

0 50 100 150 200 250 300 350 400 450 500C b ti Z G N t H ti V l (H 1212 BTU/ f) (BTU/ f)


Combustion Zone Gas Net Heating Value (H2=1212 BTU/scf) (BTU/scf)

CE vs. CZG NHV - All TCEQ Steam

100%

70%

80%

90%

100%

y (%

)

40%

50%

60%

70%

ion Efficiency

TCEQ 20:80 TNG to Propylene (S3,S4,S5,S6)

TCEQ 20:80 TNG to Propylene (S7,S8,S9,S10,S11)

20%

30%

40%

Combu

sti

TCEQ 100% Propane (S12,S13,S14)

TCEQ Extractive

0%

10%

0 50 100 150 200 250 300 350 400 450 500Combustion Zone Gas Net Heating Value (H2=1212 BTU/scf) (BTU/scf)


september 13-14, 2012 | santa ana, california · september 13-14, 2012 | santa ana, california ftir...

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