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Current and Emerging Laser Sensors for Greenhouse Gas ......Physical Sciences Inc. 20 New England...
Transcript of Current and Emerging Laser Sensors for Greenhouse Gas ......Physical Sciences Inc. 20 New England...
Physical Sciences Inc. 20 New England Business Center Andover, MA 01810
Physical
Sciences Inc. VG13-117
Current and Emerging Laser Sensors for
Greenhouse Gas Detection and Monitoring
Presented by:
Mickey B. Frish
Physical Sciences Inc.
20 New England Business Center
Andover, MA 01810
MIRTHE Workshop on Air Monitoring in Energy Extraction
August 9, 2013
Princeton University
Princeton, NJ
Physical Sciences Inc.
Outline
Needs and Applications for GHG Sensing
Descriptions of Current Laser Sensing Technologies for
CH4 and CO2
– Near-IR vs Mid-IR
Future applications for Mid-IR ICL/QCL Sensors
– Laser and detector technology development needs
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NEEDS AND APPLICATIONS
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Better Tools for GHG Science
Good science demands good data
– Accurate, reliable widespread sensors
– Skilled people to operate sensors and interpret data
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– Limaico, et. al, “Urban Ambient Variability of Greenhouse Gases: A Year
Assessment”, MIRTHE Summer Workshop, August 2013, Tuesday Poster.
Methane Concentrations at New York Botanic Garden Station
Superstorm Sandy
Is this an errant
sensor or the real
effect of Mother
Nature???
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Anthropogenic CH4 – Natural Gas
US natural gas system:
– Gathering
• >493,000 active natural-gas wells (90% use fracking) across 31 states in the U.S. in 2009
– Transmission
• ~250,000 miles of pipeline,~ 1700 transmission stations,~17,000 compressors.
– Distribution
• 500-1000 gate stations ,~132,000 surface metering and pressure regulation sites,
>1,000,000 miles pipeline, >61,000,000 end-user customer meters.
– Maintaining the security and integrity of this system is a continual legally-regulated process
of searching for, locating, and repairing leaks
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CH4 Fugitive Emissions Example
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Elevated methane concentrations on Boston streets measured by vehicle-
mounted mobile near-IR laser-based Cavity Ringdown Spectrometer.
-- Attributed to leaky pipelines --
--Source : New York Times, Nov 20,2012
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Natural Gas Leaks –
An Environmental Problem? VG13-117 -6
“American consumers are paying billions of dollars for natural
gas that never reaches their homes, but instead leaks from aging
distribution pipelines, contributing to climate change, threatening
public health, and sometimes causing explosions.”
Total U.S. Unaccounted for Gas from Natural Gas
Systems from 2000-2011a
2.6 trillion cubic feet of natural gas
Total U.S. Reported Emissions from Natural Gas
Distribution Systems from 2010 - 2011b
Equivalent to releasing 56.2 million
metric tons of CO2
Significant Incidents on U.S. Natural Gas Distribution
Systems from 2002-2012c
796 incidents / 116 fatalities / 465
injuries / $810,677,757 in property
damage
--- “America Pays for Gas Leaks”, Report Prepared for Senator Edward J. Markey, July 2013.
• But how much atmospheric methane anthropogenic vs biogenic?
Sensors and science are needed!
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Anthropogenic CO2 – Fossil Fuel Combustion
Calculated fossil fuel CO2 emissions all sectors – power production, industrial, mobile,
residential, commercial, and cement
Project Vulcan, K. Gurney, Purdue University, 2002.
Not illustrated: CO2 pipelines
– 3900 miles existing CO2 pipelines support enhanced oil recovery (EOR)
– Network emerging (~120,000 miles by 2050) to support carbon capture and sequestration (CCS)
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Tools for Detecting GHG Sources
Reliable, cost-effective tools are needed to:
– Monitor and map (spatially and temporally) sources of escaping CH4 and CO2
– Provide sufficient sensitivity and resolution to distinguish local GHG sources from
ambient
– Provide fast health and safety danger alerts
Current and emerging tools include:
– Permanent or mobile/aerial trace gas detectors
– Permanent open-path sensors for fenceline monitoring
– Sensor networks for mapping ~ km2 areas and measuring fluxes at surfaces and
sub-surface downholes
– Future networks will comprise ~100s – 1000s of inexpensive continuously-
operated spatially and temporally correlated sensors
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CURRENT LASER-BASED SENSORS
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Tunable Diode Laser Absorption Spectroscopy (TDLAS)
Competitive Features
Selective; generally insensitive to cross-species interference
Sensitive; sub-ppm detection of many gas species
Fast; sub-second response time
Configurable; point, open-path, or standoff sensor
Non-contact; only the probe beam need interact with the analyte
TDLAS is an active optical method for detecting and quantifying one or
more analyte gases mixed with other gases
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Accepted as rugged, reliable, accurate commercial industrial sensors and analyzers
Thousands currently in use
Emerging high-volume market opportunities (process control, environmental
monitoring) demand: reduced cost, simplicity, autonomy, reliability, and accuracy
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TDLAS Technology Niche
Near-IR TDLAS now fulfills many GHG sensor needs
– Near-IR is suitable and preferable for sensing many simple molecules
– Sensors utilize proven robust electronics platforms
• Reliable laser sources
• High precision
• Very low power consumption (< 1 W)
• Compact
• Minimal maintenance
• Acceptable cost; ~$10,000 per sensor unit
Mid-IR interband cascade lasers (ICLs) and quantum cascade lasers
(QCLs) enhance sensitivity over short paths
– Enables miniaturization and detection of trace pollutants and complex
molecules
Mass-produced chip-scale TDLAS sensors may enable future
wide-area deployment of sensor networks
Mid-IR Challenges:
– Low-noise uncooled mid-IR detectors
– Laser cost, power consumption, wavelength diversity, availability, reliability
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Practical TDLAS Detection Limits for Some Gases
ppm-m
Near-IR (<2.2 μm) 2 to 3 m 4 to 8 m
Gas 300 K
1 atm
Gas 300 K
1 atm
300 K
1 atm
flames 300 K
1 atm
flames
HF 0.2 HCN 1.0
H2S 20.0 CO 40.0 0.02 0.7 0.0001 0.005
NH3 5.0 CO2 1.0
H2O 1.0 NO 30.0 0.6 3 0.03 0.2
CH4 1.0 NO2 0.2
HCl 0.15 O2 50.0
H2CO 5.0 C2H2 0.2
Mid-IR laser sources spanning wavelengths from 3 -12 µm, enable sub-ppm-m detection of
many complex hydrocarbons, TICS, and chemical agents
Optical methods provide long optical path lengths to sense trace concentrations (~ ppbs)
Open-path
Multi-pass Herriot cell
Resonant cavities
Intra-cavity Optical Spectroscopy (ICOS)
Cavity Ringdown Spectroscopy (CRDS)
Solid-state nanoresonators
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TDLAS Examples and GHG Sensing Applications
I n s t r u m e n t a t i o n S h a c k
L a s e r T r a n s c e i v e r
O p t i c a l F i b e r a n d I n t e r f a c e C a b l e ( U p t o 1 0 0 0 m C a b l e L e n g t h )
L a s e r B e a m
P a s s i v e R e t r o r e f l e c t o r
D - 1 0 5 8 z
P r o c e s s i n g A r e a
2 0 0 M e t e r s
Extractive:
Localizing leaks in pipeline components
such as valves and fittings.
Point:
Permanent installation at surface and
subsurface or downhole sites.
Open Path:
Continuous and permanent pipeline health and
safety monitoring.
In-situ:
Monitoring and controlling CO2 separation
processes.
Standoff:
Surveying pipelines or surface areas
from walking, mobile, and aerial
platforms.
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Absorption Spectroscopy Fundamentals
• Gas molecules absorb light at
specific colors (“absorption lines”)
Beer-Lambert law
Iν = Iνo exp [S(T) g( - o) N]
where:
= optical frequency (= c/l)
o = line center frequency
g() = lineshape function
= path length
N = absorbing species number density
S(T) = temperature dependent linestrength
Iνo = unattenuated laser intensity
I = laser intensity with absorption
DI = change in intensity (= I0-I)
c = speed of light
l = wavelength of light
Absorbance = - ℓn (I /Io)
≈ DI/I0 ( with small DI)
CH4 Spectrum
Mid-IR fundamental
Near-IR overtone
200x linestrength advantage is
the mid-IR appeal
(when deployed judiciously)
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TDLAS System Components
A frequency agile (i.e. tunable) laser beam transits an analyte gas sample
Laser wavelength scans repeatedly across absorption line unique to analyte gas
Received signal processed to deduce analyte concentration
Laser sources
– SWIR – Distributed Feedback (DFB) laser or
– SWIR – Vertical Cavity Surface Emitting Laser (VCSEL)
– MWIR – Interband Cascade Lasers
– LWIR – Quantum Cascade Lasers
d
d
Wavelength
Laser
lo
Control
Signals
Signal
Processing
Electronics
Output
Detector
Focusing
Optics
Absorbing Gas
C-5215ez
Tra
nsm
issio
n
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Portable Standoff near-IR TDLAS for Natural Gas Leak Survey
Like a flashlight, laser beam illuminates a surface
Senses analyte gas between transceiver and illuminated surface
– Standoff range ~100 ft with handheld transceiver
Scanning laser beam across plume results in rapidly changing analyte gas measurement
Can detect hazardous gas levels through windows for emergencies and responder safety
~2000 RMLDs in use for natural gas leak surveying; CO2 version in demonstration
Remote Methane Leak Detector (RMLD™)
Commercial product (since 2005)
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Other Standoff Configurations
Manned Aerial Commercial Pipeline Leak Survey Service
D. Picciaia et.al., Proceedings Sardinia 2011, Thirteenth International Waste Management and Landfill Symposium
Mini-UAV
Lab prototype –for mapping
landfill CH4 emissions
Mobile
Portable Extractive
New commercial product
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Robust High-Precision Ambient CO2 Sensor
Near-IR (2.0 µm) – ICOS design (~60m optical pathlength)
Measures CO2 mole fraction in dry air to 1:3000 with 1 minute averaging
Applications:
Monitoring CO2 sources, sinks, and transport
Sequestration site monitoring and leak detection
Measurement Cell
Diaphragm Pump
WMS Board
Laser & System ControllerAC-DC
Power Supply
Dryer
Detector
Module
DC Power and
Signal Input
Board
Pressure
Sensor
Measurement Cell
Diaphragm Pump
WMS Board
Laser & System ControllerAC-DC
Power Supply
Dryer
Detector
Module
DC Power and
Signal Input
Board
Pressure
Sensor
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Thompson Farm Atmospheric Observatory Sensor Intercomparison, 3 – 31 July, 2008
Peaks occur at night when winds are calm, mixing is minimized and CO2 from plant
respiration builds up
Intercompared with UNH NDIR sensor
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0.1 Hz
1 5 m i n
Open-Path CO2 – PSI site, Andover, MA
August 2011
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Near-IR
Continuous operation
No adjustment, calibration, or zeroing
Diurnal variations correlate with point sensor
measurements
Leaking CO2 yields statistically distinct signature
Noise
suppressor
off
100 l/min
CO2
release
Tropical
Storm
Irene
Start Labor Day
Weekend
11
08
21
12
00
11
09
03
12
00
Signal Strength Lost
Data
Log
300
400
500
[CO
2]
(pp
m)
LBNL’s NDIR
Near-Ground
Point Sensor
Point Sensor
Apparatus
CO2 release
source
Open-Path
Transceiver and
Control Unit
Noise signal
Leak Alarm signal
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Permanent alarms to detect and
mitigate small to potentially
explosive leaks
– Near-IR
– Wireless
– Solar-powered
– Real-time alarm notification
– Easy installation & alignment
Currently in demonstration
– 600’ ft path
– Months of maintenance-free
operation
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K-6090
Pipelineunderroad
1m
ile
Pipeline Monitors
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Methane Open Path Data
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July 2013
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EMERGING MID-IR SENSORS
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FuelFinder™
Intended for locating leakage of
refined petroleum products from
buried distribution pipelines
– Primarily gasoline
Man-portable mid-IR
backscatter TDLAS
– Wavelength ~3 µm
Capitalizes on recent
advances in Interband Cascade
Lasers (ICLs) that operate at
room temperature
Senses volatile complex
hydrocarbon vapors
Projected Beam
Laser Dewar
InAs Photodetectorand Preamp
Collected
Backscatter
Receiver Primary Mirror
15 cm
12 mmOptical Breadboard
Wall Plug Power
RS-232 InterfaceControl Electronics
40 cm
Laser Detector PrimaryMirror
30 cm
F-8799
Side
View
Top
ViewProjected Beam Collected
Backscatter
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• For airborne (UAV and balloon) CO2
measurements − A precise instrument rugged enough for the
field and economical enough for widespread
use by monitoring networks.
• Requirements: − 1 ppmv precision @ ~0.1 Hz
− < 100 gm
− Battery power
− Deployable in an unconditioned payload
• Solution: − Absorption spectroscopy using room-temperature
mid-IR LED integrated with a miniaturized control
and signal processing system
Miniature Low-Power Airborne CO2 Sensor
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Thermally Stabilized SubstrateCMOS Substrate
Detector
DetectorElectronics
Coupling Structure
SolderBondPad
K-4691
Laser Die
Sensing Element
Vision – Chip-scale Mass-Produced TDLAS
Integrated-Optic Sensors and Networks
Laser source, photodetector, and optical gas sampling element integrated on a miniature
monolithic platform
– Each envisioned device senses one chemical;
• Several devices working in tandem sense several chemicals
– Novel gas sensing elements use solid-state optical waveguides
Fabricated using established production techniques
– Complete assembly with electronics in cell-phone style package
– Cost ~ few $100’s when produced in quantities of hundreds of thousands or more
– Similar to proven commercial near-IR telecom products
Naiini,M.M, et.al.,Solid-State Electronics,74,58 (2012).
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Application Distributed Sensor Networks
Each sensor detects one of a choice of
several chemicals
All sensors communicate wirelessly
with a central processor
Network provides wide area coverage
and improves average sensitivity
compared to individual sensors
CentralProcessor
12
3
1
1
2
2
3
1
3
2
J-6764
(not to scale)
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Cost Challenges
Mickey’s Mantra:
– “TDLAS is not much more complex than compact disk players”
– “The smallest and lowest cost currently-available TDLAS sensors
fit in a smoke-alarm type package weighing about three pounds”
– “Yet TDLAS sensors cost >$10,000 per unit,
• Despite laser chip costs that could be ~$50 -$100 each
if designed for low-power spectrometry and produced
in many tens of thousands
Cost drivers
– Laser packages intended for telecommunications industry
produced in relatively low volumes @$1000 each
– Bulk optical components
– Discrete component electronics
Impact
– TDLAS today is too expensive, bulky, and power-hungry to deploy
practically in distributed sensor networks
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Technical Challenges
Practical devices require improved power efficiency, specifically for
laser and detector thermal control
– Solutions:
• Harness laser waste heat efficiently
• Design for uncooled detectors
– Smaller is better
Detection goals require:
– Mid-IR lasers
– High-Q resonant sensing elements
– Simple optical coupling between sensor element, laser source, and detector
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TDLAS Laser Sources vs. Needs Near-IR example
Distributed FeedBack (DFB)
Laser
– 14-pin butterfly package with
integral thermo-electric cooler
– ~10 mW output power
– Optically-isolated fiber optic output
– ~ 700 – 2300 nm
Vertical Cavity Surface
Emitting Laser (VCSEL)
– TO-8 package with integral
thermo-electric cooler
– ~0.4 mW output power
– Fiber-coupling optional
(w/reduced power)
Top View
Side View
ElectricalConnections
KovarEnclosure
Cement-filledTube
StrainRelief
OpticalFiber
Fiber TipLens
Optical Isolator
Laser
Transmitter
Photodiode
CopperSubmount
ThermoelectricCooler
J-6640
Monolithic spectrometers need:
– µW’s of laser power
– Stable, but not necessarily sub-ambient,
laser temperature
COTS Lasers are Overkill
Need: Near and Mid-IR Lasers designed
for widely-deployed gas sensing
applications
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Novel Packaging to Meet the Challenges
Eliminate thermo-electric cooler (TEC)
– Heat, don’t cool
Proven in near-IR benchtop configuration
Eliminate microlenses and optical isolator
– Enabled by monolithic integrated platform
Simplify Electronics
– Reduce to ASIC
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Summary
Near-IR laser sensors for natural gas leak detection are established
widely-accepted commercial technologies
– One of the largest laser-based gas sensing applications
– CO2 sensors are available using similar sensor platforms
Widely-deployed sensors for “ubiquitous monitoring” will benefit
from mid-IR integrated optics
– Requires laser sources designed for gas sensing application
– Cost per laser <$100 in mass production
– Developing these sources is the challenge to the MIRTHE community
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