mit photonics in energy_a mendez_june 2009

MCH Engineering, LLCA.Mendez

1Optics and Photonics forAdvanced Energy Technology

Optical Gas Sensors forEnergy Applications

Alexis Méndez, PhDMCH Engineering, LLC1728 Clinton Ave., Alameda, CA [email protected](510) 521-1069

MIT-OSA Optics and Photonics for Advanced Energy TechnologyMIT, Cambridge, MA. June 25, 2009



Outline

• Introduction

• Gas sensing techniques

• Applications:– Electric Utility– Petrochemical & Refineries– Gas Transmission & Distribution– Hydrogen Fuel Cells

• Conclusions



Introduction



Why Gas Sensors in the EnergySector?

Various types of gases are normally used, produced or emittedas part of the operation and processes of different energy-related industries.

These gases need to be detected, monitored, measured,analyzed, suppressed, and/or removed. Therefore, practical,effective and low-cost gas sensors are a valuable tool for plantoperation and maintenance in the Energy industry.

Optical and photonics based gas sensors and sensingtechniques, offer among the most flexible, sensitive, multi-species, effective and practical solutions for gas sensing.



Gas Sensors:Energy Sector Application Segments

Electric Utilities- Plant emissions- Boiler optimization- SF6 Fugitive emissions- Transformer dissolved gases

Fuel Cells- Transportation- Stationary- Portable

Hydrogen Production- Pipeline Monitoring- Storage Tanks- Fugitive Emissions

Petrochemicals & Refineries- Fugitive emissions- Gas analysis & composition- Stack emissions- Combustible gases- Hazardous gasespersonnel safety

Gas Transmission & Distribution- Fugitive emissions- Leak detection- Moisture content- Gas composition- Impurity detection



Main Drivers

• Environmental Regulation & Protection

• Pollution Reduction & Control

• Plant Protection & Personnel Safety

• Process Optimization

• Reduction in Opex and Maintenance Costs



Environmental Issues:U.S. Greenhouse Emissions

• A significant port of the USgreenhouse gases are produced bythe energy sector.

• The largest pollutant contributor isCO2 from coal burning power plants.

• Other gas sources are fugitiveemissions in refineries, petrochemicalplants and pipeline networks; as wellas from SF6 leakage from gas-insulated electric power equipment.



Greenhouse Gases:Environmental Impact Capacity

Greenhouse gases GWPCarbon dioxide (CO2) 1Methane (CH4) 21Nitrous Oxide (N2O) 310Hydrofluorocarbons (e.g., HFC 134a) 1300Perfluorcarbon (e.g., CF4) 6500Sulfur Hexafluoride (SF6) 23,900

Global Warming Potentials (GWP)(100 year time horizon)



Inventory of U.S. UtilityComponents

• 5,000 Generating power plants

• 1,000 Boilers

• 27,000 power transformers

• >300,000mi of natural gas pipelines

• 150 RefineriesSource: DoE/EPRI



Gas Sensing Techniques



Key Gases to Measure

• O2

• CO• CO2

• H2

• H20 (vapor)• H2S• HCL• HFC

• CH2

• CH4

• NH3

• NO• NO2

• SF6

• SO2



IR Gas Absorptions Bands

From Daylight Solutions

Most gases absorb IR light, causing their molecules to bend, stretch or twist

IR absorption is proportional to gas concentrations



Spectral Measurement Techniques• Visible Light Spectroscopy

– Colorimetric– Fluorescence– Luminescence

• Near-Infrared Absorption Spectroscopy– TDLAS– Cavity Ringdown

• Mid-Infrared Spectroscopy– FTIR– TDLAS– Scattering– Photo Acoustic

• Raman Spectroscopy• Optical Imaging



Spectroscopy Techniques:FTIR vs. Raman

Source: Spectroscopy

FTIR measures how muchLight is absorbed or reflected

Raman measures the emitted lightfrom an excitation light impulse



Spectroscopy Techniques:Dispersive vs. Non-Dispersive



Spectral Backscatter Absorption

Back reflected scatter light can bedetected or captured by an IRimaging camera.



Tunable Diode Laser AbsorptionSpectroscopy (TDLAS)

• Select a single absorption line forspecific gas.

• Ensure no cross-interference with othergases or background stream.

• Pre-tune laser by temperature to centerof absorption line.

• Scan absorption line by current tuning oflaser, so as to reconstruct absorptionenvelope.

• Calculate gas concentration fromamplitude and shape of 2nd harmonic ofdetected absorption line.



TDLAS Configurations

Reflective Transmissive



Cavity Ring-DownSpectroscopy (CRDS)

Source: Picarro

• Measures decay constant, not absorption intensity• Independent of light source fluctuations• Absolute measurement of concentration



Photo-Acoustic Spectroscopy (PAS)

Modulated IR light produces a pressure (acoustic) wave in the

gas cell, which is then detected by a phase-sensitive microphone.



Photonics Components Needed

• Optical Sources– Quantum Cascade Lasers– Tunable lasers– Fiber lasers– LEDs– Broadband sources

• Detectors– CCDs– UV, VIS, IR detectors– Multi-spectral spectrometers

•Light Processing– Filters– Imaging– Beam steering

•Light Guiding– IR waveguides– Specialty optical fibers– Lenses



Electric Utility Applications



Schematic of a Coal-FiredPower Plant

Gas Sensing



Coal-Fired Boiler:Optical Gas Sensing

Real time, in-situ measurements allow for accurate, zone-specific data.Combustion optimization leads to:

• More power output better heat and consistent operation• Less coal consumption reduced CO2 and NOx emissions• Less boiler slagging



Coal-Fired Boiler:Optical Gas Sensing—Zolo BOSS System

• On-line measurement of O2, CO, CO2, H2O and temp.

• Based on multiplexed TLDAS.

• Laser is beamed across boiler flames, and can be arranged

in 2D arrays concentration CAT scan.

• Unaffected by flames, dust or ash.

• Data is used to optimize boiler operation and help reduce

emissions.



Coal-Fired Boiler:Zolo System Configuration



Power Plant:Stack Emissions



Power Plant Stack Emissions:Pollution Impact

Source: NETL

In one hour, the flue gas from a300MW coal plant would fill apipeline 10ft in diameter and 100miles long!

If the various gas species wereSegregated within the pipe, they wouldThe pipe portions shown.Mercury PM SO3 NOx SO2

0.0002m 1m 1.5m 180m 820m

N2, CO2, O2 and H2O~160 Km



Flue Emissions Monitoring:Optical Flue Gas Analyzers—Configurations

Source: SpectraSensors



Optical Stack Analyzers:Examples of Commercial Systems

Land (TLDA) Codel (IR Absorption)

Yokogawea (TDLA)

Picarro (CRDS)



SF6 Gas:Characteristics

• SF6 is a synthetic gas expensive ($20/lb)

• Excellent electric insulator high dielectric strength, arcquenching, inert, inflammable, 5x heavier than air.

• Widely used as insulator in HV equipment breakers,transformers, cables, switchgear, etc

• High global warming potential 23,900x that of CO2

• Atmospheric suspension lifetime of 3,200 years!

• The Kyoto protocol calls for reducing SF6 emissions



SF6 Gas:Fugitive Emissions

• SF6 emissions can escape duringthe service life of HV equipmentthrough seals and leaks.

• Releases also occur duringequipment installation, chargingand servicing.

• In 1999, SF6 U.S. electric utilityemissions were estimated at 4.7million metric tons of carbonequivalent.

• Electric utilities worldwide, haveactive programs to detect andmitigate SF6 fugitive emissions.

Source: EPA

US SF6 Fugitive Emissions Trend



SF6 Gas:Detection of Leaks & Fugitive Emissions

GasVue TG-30Backscatter IR absorption ImagerReal time image of SF6 leaksVideo output for TV display30 meter range2:1 zoom for close-up viewing

SF6- IR LeakG.A.S., Dortmund, GermanyDual λNon-Dispersive IR Spectrometer1ppm sensitivity0-2,000ppm range

Sherlock System



Power Transformers:Dissolved Gas Analysis

The quality of the insulating oil in power transformer degradesas a result of normal and abnormal operation, aging, partialdischarges and short circuit faults.

Moisture, particles and a number of dissolved gases areproduced, that are an indication of the transformer’s condition.

Source: Siemens



Petrochemical applications



Fugitive Emissions:Refineries & Chemical PlantsFugitive emissions are produced by leaks of hydrocarbon vapors fromprocess equipment—such as valves, flanges, pumps, etc.

Leaks occur randomly. In a typical U.S. refinery, the number of fugitiveemission components is > 200,000. Inspection is commonly done manuallywith gas sniffers. Opex costs exceed $1MM.

VOCemissionsSource Number lb/dayValves 11,500 6,800Flanges 46,500 600Pump seals 350 1,300Compressor seals 70 1,100Relief valves 100 500Drains 650 1,000Cooling towers 1 1,600Oil/water separators 1 32,100

TOTAL 45,000

Average emissions in a US refinery



Fugitive Emissions:Spectral Detection Techniques

Active Detection - requires illuminating the scenewith a laser operating at an Infrared (IR) wavelengthwhere the laser light is absorbed by the target gas butreflected by the background.

Passive Detection - relies on measuring thetemperature difference between the temperature of thegas and the temperature of the background.



Fugitive Emissions:Optical Detection Systems

Long-wave IR Mid-wave IR

Spectral backscatter reflection imaging

Simulated methane leak in a pipeFLIR SystemsThermaCAM



Gas Transmission &Distribution Applications



Producing Wells

Transmission Lines

CompressorStations

UndergroundStorage

Regulators/Meters

Distribution Lines

LNG or Propane Plant

CommercialCustomers

ResidentialCustomers

Regulator/MeterLarge Volume Customer

Processing Plant

Gathering Lines

Natural Gas:Transmission & Distribution Network

Approximately 300,000miles of gas pipelines



Natural Gas Pipelines:Moisture Measurement• By law, the content of moisture in natural gas pipelines has to be

<7lbs/MMSCF (147ppmv) which is known as the “tariff” value.Otherwise, penalties are imposed.

• Water vapor is present in unprocessed NG in various amounts,and its presence can have serious consequences such as:

– Internal pipeline corrosion– Freezing of valves and regulators– Formation of hydrates that obstruct flow– Reduction in gas BTU value– Condensation at compressor stations



Natural Gas Pipelines:TLDAS Moisture Sensing Systems

GEAurora System

Spectra SensorsSS-2000 System



Gas Sensing & Leak Monitoring:Multi-Point TLDAS System

• Monitor >300 points in-situ, and real time• Long distance range(~10 km)• Single or multiple gas species



Fuel Cell Applications



The Future Hydrogen Economy

Source: Air Products



Fuel Cell Types

Fuel Cells

PortableTransportation

Stationary



Hydrogen Sensors:Application Markets

Aerospace- Rocket & propulsion systems- Liquid fuel tanks

Fuel Cells- Transportation- Stationary- Portable

Hydrogen Production- Pipeline Monitoring- Storage Tanks- Fugitive Emissions

Hazardous Locations- Refineries- Oil & Gas Platforms- Mining



Hydrogen Sensors:Detection Roles

Leak Detection– Identify any incipient H2 gas leak or fugitive emission– Very high sensitivity—1,000 to 40,000 ppm– Fast response (<10 sec)

Alarm Sensing– Detect and warn of H2 accumulations within explosive limit– Medium sensitivity—0.5 to 4% (H2 LFL)– Medium response time— ~10sec

Purity Monitoring– Indicate concentration and relative H2 purity– Sensitive in the 40 to 99.9% concentration range



US National Energy Renewable Labs(NERL): FO H2 Sensor



Market Size



443

752935

1260

1710

0

400

800

1200

1600

2000$ Millions

1994 1999 2004 2009 2014Year

Global Gas Sensors Market

Process control8%

Industrial safety33%

Automotive2%

Fire and domesticgas detection

33%

Security anddefense

12%

Environmentalmonitoring

2%

Medical8%

Other2%

Source: The Freedonia Group



Global Demand for Gas Sensors:By Technology

Source: BCC Inc.



Process Analytics Market~ $2 Billion USD

0 $100M $200M $300MSource: ABB



Conclusions• Optical and Photonic gas sensors and sensing techniques are

practical, effective tools to the Energy Sector.

• Optically-based gas sensing systems offer not only technicalimprovements, but significant environmental and cost benefits.

• Energy sector applications for optically-based gas sensors can befound in coal-fired boiler optimization, stack gas analysis, fugitiveemission detection, natural gas moisture measurement, leakdetection in pipelines, and many others.

• Several systems are commercially available.

• Advancements in lasers, laser diodes, imaging detectors, andother optical components, will need to improved gas-sensingdevices at lower cost.

mit photonics in energy_a mendez_june 2009

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