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

[email protected]

MIRTHE Workshop on Air Monitoring in Energy Extraction

August 9, 2013

Princeton University

Princeton, NJ

mailto:[email protected]

mailto:[email protected]


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

VG13-117 -1

Physical Sciences Inc. VG13-117 -2

NEEDS AND APPLICATIONS


Better Tools for GHG Science

Good science demands good data

– Accurate, reliable widespread sensors

– Skilled people to operate sensors and interpret data

VG13-117 -3

– 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???


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

VG13-117 -4


CH4 Fugitive Emissions Example

VG13-117 -5

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


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!


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)


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

VG13-117 -9


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

-10

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

VG13-117


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

VG13-117 -11


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


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.

VG13-117 -13


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)


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

Physical Sciences Inc. -16

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)

VG13-117


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

-17 VG13-117


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


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


0.1 Hz

1 5 m i n

Open-Path CO2 – PSI site, Andover, MA

August 2011

VG13-117

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

-20


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

VG13-117

K-6090

Pipelineunderroad

1m

ile

Pipeline Monitors

-21


Methane Open Path Data

VG13-117 -22

July 2013


EMERGING MID-IR SENSORS

VG13-117 -23


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

-24 VG13-117

Physical Sciences Inc. -25

• 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

VG13-117


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).

VG13-117 -26


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)


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

VG13-117 -28


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

VG13-117 -29


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

VG13-117 -30


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

VG13-117 -31


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

VG13-117 -32

current and emerging laser sensors for greenhouse gas ......physical sciences inc. 20 new england...

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