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ICAC/EPA Round-table
Meeting
Peter G. Zemek, PhD
CTO, MKS Instruments
Boston, USA
May 2015
An Optical Sensor for
Real-Time, Speciated
Gas and Liquid Measurement
Electromagnetic Spectrum
Optical Instruments
Light – Particles and Waves
Higgs Boson particle
Photon spin is not constant
Double Slit “Wavicles” Higgs-Boson Particle
Quantum gets both impacts like
particles and interference patterns
like wavesCourtesy of Youtube
Courtesy of Wiki
MKS Instruments
$1.6B
4900+ employees
https://www.mksinst.com/
MKS Instruments
Fourier Transform Infrared (FTIR)
Spectrometry– SO3/H2SO4 SCR, Scrubber (H2O 40% by Vol)
– NH3 Slip
– NOx, SO2, CO/CO2, CH4, any dipole
Solid State Laser– Ultralow trace level
Non-Dispersive Infrared (NDIR)
Tunable Filter Spectrometer (TFS)
Do
wn
str
eam
M
idstr
eam
Up
str
eam
Innovative Optical Device Developed for HPI
>2700 Installations
Designed for Purpose
Shock, Vibration, Unattended
On-line & /or Portable
Ambient temperature
Delta
Sample temperature
Vibration & shock
Humidity
Wet-Gas
Easy Installation
Quick Warm-Up time
Fast Response Time 5
sec
High Accuracy
Good Repeatability
Great Linearity
Stability
Remote control
No Calibration
Zero-Drift
Ruggedness
Price
Cost of Ownership
What are we talking about?
Tunable Filter Spectrometer (TFS)
Key customers:
• Saudi Aramco, Gasco, ADGAS
• BP (UK and Germany)
• BASF
• Shell
• Wartsilla
• SinoPec Guangzhou Petroleum
• CNPC Jiangyou Plant
• CNPC Dalian West Pacific
+ Fiber Based Liquid (Cryogenic) Probes
OEM Design – Customized Needs, Gases, LOD
CE, ATEX, CSA, UL, Class I DIV I or II
IECEx,NEMA4X, IP66
TFS Technology Differentiation
Comparison to other major competitorsTFS FTIR NDIR Laser
Based
Sensor
GC Significance
Specificity High High Low High High Ability to measure target compound in
complex real-world mixes
Sensitivity High High Med High High Ability to measure trace components
accurately
Multi Compound
Monitoring
Med Multi Single Single Multi Ability to monitor multiple components with
one instrument. Requirements of most
applications.
Reponse time Fast Fast Fast Fast Slow Ability to response to the variation of the
monitor gas promptly
Cost of
Ownership
Low Med to High Low Low High Low cost of ownership is a prerequisite for
wide industrial deployment of technology
FTIR: Fourier Transform Infrared Spectroscopy
NDIR: Non-Dispersive Infrared Spectroscopy
GC: Gas Chromatography
FID: Flame Ionization Detector
CRDS: Cavity Ring-down Spectroscopy - * Depending on the LOD needed but typically 1 cmpd for CRDS
CLD: Chemi-luminescent Detector - NOx
1 TFS Replaces – FID, NDIR, CRDS*, CLD
Expanding into all Markets
Total BTU, Wobbe, MN, Sp Grav. C1-C6+
Speciation, Blending, Olefins, LNG/LPG
Semi-Endpoint, Etch, and Clean Detection
HRVOC – Highly Reactive VOCs (Propylene,
Ethylene, 1,3-Butadiene, Butenes)(0-100ppm)
Air Separation Units (ASU)
CO+CO2+CH4+H2O+N2O+THC(alkanes)
------------------------
Acid Gases- HCl, HBr, H2SO4, etc
CEM Criteria Pollutants – NOx (NO2, NO), SO2
Air Toxics/HAPs – HCN, Carbonyls, etc.MKS Confidential 11
Real-time, On-Line, All-Optical
Speciated Gas Analyzer
OEM Fuel Feed
Gas analyzer, providing:
Individual alkane component concentration, such as C1 – C6+ & CO2
BTU/CV calculated value (ISO6976)
Wobbe Index calculated value (ISO6976)
Hydrocarbon dew point
Real-time measurement in seconds
Unaffected by N2, O2, H2 and CO2
Any dipole gas measurement (IR, UV)
Low-cost installation and operation:
– No carrier gas requirement
– No calibration gases or “clean” air requirement
– Minimal “sheltering” requirement
• GC-like speciation (C1-nC6, alkanes, alkynes, alkenes, etc.)
• Fast update rate (< 5 seconds)
• Total BTU/HV from C1 to C6+ in natural gas (0-3000 BTU
linear response)
• Repeatability <+/- 0.01 MJ/m3 T(+/- 0.3 BTU/1000)
• Accuracy <+/- 0.04 MJ/m3 (+/- 1 BTU/1000) (5 x RMS noise)
• No carrier gas required
• No H2 instrument fuel gas required
• Permanently calibrated (easy to span-adjust)
• Alternative or fast-response transmitter/sensor to GC-TCD
GC Alternative
How does it work?
TFS Principle of Operation
Sample
λ
Filter FunctionFabry-Perot Etalon
Metric The TFS Advantage
Simplicity • Delivers low-cost and rugged hardware design
Wavelength Sweep • Enables multi-component analysis (4 regions 100-300 cm-1 wide)
• Provides higher selectivity and improved speciation
Larger Etendue • Higher optical throughput
• Delivers high sensitivity and low LDL capability per path length
Field proven technology. We have 2700+ delivered
sensor products based on this technology
I
TFS™ Sensor Wavelength Scanning Technology
2500 3000 3500 4000 4500 5000
0
0.5
1
1.5
2
2.5
x 10-4
3 separate regions
H2O
THC
CO2
CO
• Custom designed Fabry-Perot element
• Focused on relevant band(s)
• Wavelength scanning within the band(s) (up to 4 regions)
Light Absorption Spectroscopy with Advanced
Spectral Decomposition Algorithm
Speciated and
Quantified
Compounds
Chemometrics
Ch. # Compound Range Accuracy
1 Methane 0 - 100% +/- 0.2%
2 Ethane 0 – 25% +/- 0.2%
3 Propane 0 – 25% +/- 0.2%
4 iso-Butane 0 – 10% +/- 0.1%
5 n-Butane 0 – 10% +/- 0.1%
6 Propylene 0 – 10% +/- 0.2%
7 Ethylene 0 – 10% +/- 0.2%
Example Configuration
Challenges of Hydrocarbon
Spectroscopic Analysis
Source: www.camo.com
“A data collection task involves many measurements made on
many samples. Such multivariate data has traditionally been
analyzed using one or two variables at a time. However, this
approach fails to discover the relationships among all variables and
samples efficiently. To overcome this,we must process all of the
data simultaneously. Chemometrics is the tool for extracting
information from multivariate chemical data using tools of
statistics and mathematics.”
Effects of Light Intensity Drift to
Span Accuracy
Test Procedure:
1. Zero the instrument (pure N2)
2. Flow sample mixture
3. Reduced light intensity by 50%
4. Flow back N2
Results:
Span drift due to ~50% light
intensity reduction: < 0.03%
on all channels
Zero drift: virtually zero on all
channels (< 0.01%) without
re-zeroing the instrument
CH4: 49.72% CH4: 49.74%
=> Error: 0.03% (due to a
50% drop in light intensity)
=> Zero Drift <0.01%
Optical Throughput Advantage
with TFSTM
platforms
• Low detection limit (high sensitivity)
• Highly overlapping spectra
• Rapid measurement response
3200 3300 3400 3500 3600 3700
0
0.5
1
1.5
2
2.5
3
3.5
x 10-4
3200 3300 3400 3500 3600 3700
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
x 10-4
TFS Grating / diode array
Spectral quality difference:
Yields high optical throughput
Installs, Studies and Field Tests
Saudi-Aramco MKS-TFS Evaluation
Use ISO 6976
For Total BTU
GPA Standard 2261 in Section 2 Summary of Method the following
Note is found:
NOTE 2 – Modern technology has brought many advances in the
way natural gas can be analyzed. These advances are now
available for traditional laboratory as well as portable and on-line
gas chromatographs. Any gas chromatograph is acceptable for
analysis of natural gas as long as the specifications for repeatability
and reproducibility in Section 9 over the component ranges listed in
Table 1 are met or exceeded.
Field Trial – Pipeline Gas Analysis
• Test performance against an ‘industry-standard’ Gas Chromatograph (GC)
• Performed in a natural gas & oil well in Eastern Colorado
• Data represents a well run of over a 3-day period
0
5
10
15
20
25
30
35
40
45
1 2891 5781 8671 11561 14451 17341 20231 23121 26011
Data point
Co
ncen
trati
on
(%
)
0
5
10
15
20
25
30
35
40
45
1 3243 6485 9727 12969 16211 19453 22695 25937 29179
Data point
Co
ncen
trati
on
(%
)
Total HC gas plot from a GC-TCD
Total HC gas plot from an IR with
TFS-equipped optical analyzer
Field Trial – Data Analysis
Speciated Methane plots
0
50000
100000
150000
200000
250000
300000
1 3059 6117 9175 12233 15291 18349 21407 24465 27523
Data point
Co
ncen
trati
on
(p
pm
)
GC measurement
0
50000
100000
150000
200000
250000
300000
1 3567 7133 10699 14265 17831 21397 24963 28529
Data point
Co
ncen
trati
on
(p
pm
)
IR measurement
y = 1.0209x
R2 = 0.9886
0
50000
100000
150000
200000
250000
300000
0 50000 100000 150000 200000 250000 300000
IR reading (ppm)G
C r
ead
ing
(p
pm
)
IR VS GC readings, methane
Standard Error (SE): 0.74%
Independent Laboratory Testing
with Calibrated Mixtures (in UK)
Goals:• Evaluate accuracy and linearity
• Evaluate calibration robustness
Methods: • Use certified bottled gases & MFC
Mix 1. 100% ethane
Mix 2. 50% ethylene bal N2
Mix 3 . Mix 1 and 2 and N2
Mix 4. Methane 29.88% ,Ethane 6.987%,
Propene 14.92%,Ethylene 32.663 %
Balance (approx. 15% ) H2
Mix 5. Mix 1 and Mix 4 and N2
Mix 6 .Methane 30%,Ethane 10.04%,Ethene 29.88%,Propane 10.05% n Butane 4.93%
Mix 7. iso Butane 2.2% in N2
Mix 8 .Mix 7 and Mix 6 and N2
Mix 9 . n Butane 1.98 % in N2
Channel Compound Range
1 Methane 0 – 100%
2 Ethane 0 – 25%
3 Propane 0 – 25%
4 iso-Butane 0 – 10%
5 n-Butane 0 – 10%
6 Propylene 0 – 10%
7 Ethylene 0 – 10%
Analyzer Configuration
Accuracy – C1 to C4 alkanes &
ethylene (cont…)
Linearity
Out-of-range
ethylene
CV Measurement Linearity
Measured CV (BTU/SCF)
Th
eore
tica
l C
V (
BT
U/S
CF
)
Error (RSMEP): 1.8 BTU/SCF
(0.067 MJ/NM3)
%
40-hour Pipeline Natural Gas: side-by-
side test with a GC-TCD (CH4
values)
CH4 discrepancies: 0 – 0.3%
Due to calibration gas differences
TFS can be re-spanned as other instruments do in the field
TFS could be calibrated with the same standard as the GC
%
40-hour Pipeline Natural Gas: side-by-
side test with a GC-TCD (C2H
6values)
• C2H6 discrepancies: 0.1 – 0.25%
• Due to calibration gas differences
28 days LNG composition (GC vs TFS)
GC – daily update
(daily calibration)
TFS – 5 second updates
(no calibration, no re-zero)
As can be seen, the TFS based infrared measurements track the daily GC reading
very well, quite noticeably the low methane readings on around 8/2 and 8/15,
higher C4 readings around 8/15 and high C3 reading around 8/2.
More importantly, the infrared reading captures the fluctuations that
otherwise would be missed by the daily GC measurements.
TFS-ASU-Trace Gas Monitor (M3)
Advantages• Replacing different gas sensors in a rack
with a single multi-component monitor.
• Reducing the interference in the
measurement
• Lower ownership cost and low
maintenance
• Real time response (up to 1 Hz reporting
rate)
Packaging and interfaces:• 4U box compatible to standard 19” rack mount
• ¼” VCR fittings for gas sampling
• 110/220 V power input
• LCD touchscreen
• Modbus on TCP/IP and RS485
• 4 4-20mA Analog output
• 4 configurable actuator outputs
Measurement range 10 ppb to 1000 ppm
Multi-component monitoring; CH4, C2+ Alkanes, CO, CO2, N2O, H2O
TFS M3 System Overview
TFS Analyzer Engine:
a. Configurable filter bands
(up to 4 different bands)
b. Broadband transfer optics
(Visible to MIR)
c. Multiple detector options(
InGaAs, MCT, DTGS)
10 meter Multi-pass Gas
Cell:
a. Specially designed high
throughput cell
b. Oxygen compatible
c. Temperature up to 190 C
Electronics:
a. Algorithm fully
embedded
b. Programmable
system
settings/Analog
IOs/Interfaces
ASU Measured Results
Linearity test results (measured with CH4, CO and CO2, mixture, 5 second
measurement)
Sensitivities (5σ) in 5 second measurement (ppbv):
CH4 CO CO2 C2+ N2O
5.9 19.6 88.5 57.9 7.6
Sensitivity of Other Gases
All assume 30 second measurement time and
sensitivity is estimated by 5X RMS noise
Gases Sensitivity(ppb)
NO 100
NO2 15
SO2 20
C2H5OH 80
HCl 140
AsH3 12
SiH4 5
H2O 125
SiF4 8
Summary
Industry-first, All-optical Gas Analyzer Platform (MIR, NIR, UV)
– GC-like multi-component speciation (ie alkanes, alkynes, alkenes, dipoles)
– Fast update rate (down to 1 second)
– No carrier gas required & no instrument gas required (no purge)
– Permanently calibrated
– Accuracy & repeatability equivalent or better than a gas chromatograph
Proven Technology & Platform
– 2700+ units deployed (upstream, downstream, HPI, power)
– 350+ years of cumulative run time
– OEM, CE, or CSA/ATEX hazardous area certified
Versatile Spectroscopic Hardware Platform
– UV – midIR analysis
– Process-mounted or portable-field (24VDC)
– An attractive alternative to GC, residual oxygen and refraction based
analyzers in hydrocarbon/fuel gas analysis
– Replace multi/single component analyzers (CLD, UV,FID, NDIR, CRDS)