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Advanced Methods for Open Path FTIR Technology

Research Update

Dr. Susan Stuver February 2015

Project Goal How to measure fugitive emissions when

you don’t know what’s in the air to begin with Gas Analyzers measure only one pollutant Photo Ionization Detectors can’t source emissions

and can be inaccurate Canisters only give a snapshot Open Path Systems can: Detect 100s of gases, continuously operate,

includes meteorological data, withstand harsh weather System is being used by DoD to detect and

measure chemical threats

However, existing protocol for the use of open path technology

in oil and gas operations is outdated

Project Goal – Develop Protocol Short Term Monitoring Drilling Fracturing

Long Term Monitoring Production Compression

2 Phases Phase 1: Controlled Methane Release Phase 2: Oil and Gas Field Trials

How an OP-FTIR Works OP-FTIR System is like a

particle counter summing up total energy that given chemicals absorb at a particular wavelength

The energy measurement is compared against known spectra which is converted into a path averaged concentration

Weather data are integrated to give us the direction toward the source

How an OP-FTIR Works ad nauseam

• A beam of light spanning a range of wavelengths in the near-IR portion of the electromagnetic spectrum (approximately 2 to 14 microns) is propagated from the transmitter.

• a retroreflector comprised of an array of corner-cubed mirrors, is

positioned to intercept this radiation and redirect it back upon itself to the receiver.

• An interferometer splits the returning beam into two paths, and

recombines them in a way to generate an interference. The interference, is dependent on the wavelengths present in the beam.

• In one of the paths, the radiation is reflected off a moving mirror,

resulting in an intensity variation which is measured as a function of the path difference between the two mirrors; the result is an interferogram.

How an OP-FTIR Works ad nauseam

• The interferogram that is obtained from a monochromatic beam is a simple cosine wave.

• The broadband interferogram is a sum of cosine waves (the Fourier series) for each spectral component as a function of mirror-beam-path separation.

• A spectrum in the optical frequency units is obtained by performing a Fourier transform upon the interferogram.

• Contaminants of concern are identified and quantified via a computer-based spectral search involving sequential, compound-specific analyses and comparison to the system’s internal reference spectra library.

• FTIR spectral data is analyzed via multi-component classical least squares (CLS) technique.

• Any gaseous compound which absorbs in the IR region is a potential candidate for monitoring using this technology.

Phase 1 Primary Equipment

Kassay RAM 2000 G2 and 37 Cube Retroreflector Heavy duty tripods

Climatronix Integrated F460 Weather Station Copper grounding rod

RM Young 3D Ultrasonic Anemometer Meteorological Translator

Phase 1 Primary Equipment Methane Release System

Methane Cylinders 2 Stage Regulator AALBORG Mass Flow

Controller Teflon Tubing Swagelok fittings and Snoop Bucket Release System Stabilization Cart

Generac Inverter Generator Gasoline powered

Phase 1 Primary Equipment Air Gas Methane Release

System Methane Cylinders 2 Stage Regulator AALBORG Mass Flow

Controller Teflon Tubing Swagelok fittings and Snoop Bucket Release System Cart

Solar Powered Generator

Phase 1 Remote Power Solar Powered

Generator Deep Cycle Battery Battery Box Solar Power Intelligent

Photovoltaic Controller Raptor 1000-3000 watt

power inverter

Gasoline generators not allowed in explosive environments

Diesel generators push too much current for sensitive instrumentation

Phase 1 Secondary Equipment Laptops – one for the OP-FTIR, one for the Anemometer Extension Cords – 100 foot and 50 foot Surge Protector – 6 plugs works best Grounding Supplies – clamps, wire, rod and cutters Compass – finding true north GPS – instrumentation coordinates for modeling Measuring Wheel or Range Finder – beam path

measurement Equipment dollies and Storage Containers – Safe movement

– horse trailer works best Folding table and Canopy – work station

Other Stuff that makes life easier…

First Aid, bug spray, sunblock, extra water, snacks, shade structure, small fan, space heater, cooler

Camera, phones, tablets, internet connectivity Chairs – at least 4 Stakes – at least 12 Rope – tie downs Tarps, canopies or plastic sheeting – in case it rains Tape – duct, electrical, thread Flashlights Small ladder – weather station adjustment Tool box with at least:

Multiple size wrenches, crescent wrench, Allen wrenches – both English and metric, hammer, zip ties, scissors, wire cutters

Site Design: Controlled CH4 Release

Retroreflector

Methane release

F460 Weather

Anemometer

OP-FTIR

Site Design: Pilot Test

Instrument Prep: Chemical Setup Potential to measure 100’s of analytes

For simplicity, 11 were chosen

Benzene, Toluene, Ethylbenzene, O-Xylene, M-Xylene, P-Xylene, Propane, Ammonia, Carbon Monoxide, Methanol, Methane, Water- chosen as an interferent

An interferent is a chemical with a spectral

region that overlaps the chemicals you wish to analyze. Interferents (like water vapor) can cause erroneous concentration readings unless they are mathematically removed from the analysis.

Instrument Prep: Water Vapor RMMSoft automatically adjusts for water vapor present in all sample spectra. Water vapor is “cancelled” from each spectral frame (background subtraction) due to the presence of water vapor in the background data, as well as the actual data run. Additionally, water vapor is listed as an interferent for every analyte of interest, and is algorithmically accounted for in each sample frame. (Section 9.11 EPA Method TO-16).

Chemical Setup - Screenshot

Concentrations shown as a “C” in their known spectral regions

Water Vapor is an interferent and is shown as an “I” in its known spectral regions. An “I” can be assigned to any chemical you wish to remove from the analysis

Instrument Prep: QA/QC Noise Equivalent Absorption (NEA)

NEA evaluates the performance of the system – think of it as laser-based diagnostics.

During an NEA analysis, the program will compute the Mean, Maximum and Standard Deviation of the NEA in 3 spectral regions and will automatically evaluate each against a pre-defined tolerance.

If any regions’ mean is greater than the tolerance, the NEA Noise for that region is marked as Out of Spec.

Lots More QA/QC

Measurement of Return Beam Intensity (S/N, saturation sampling tests)

Measurement of Stray Light Instrument Detection Limit

Determination of Precision

Determination of Accuracy

Measurement of Resolution

Determination of Non-linear Instrument Response

Demonstration of Capability (DOC)

Spectral Interference

Water molecules, present in heavy fog or rain, may saturate the modulated signal received at the detector. The absorbance of water covers a broad wave number region and overlaps with regions of other gases. “NO DATA”, will register on the software display, as a result of the saturation.

Heavy precipitation or condensation on the Retro-reflector may create physical interferences in the energy pathway, which result in degraded voltages. If the voltage is low enough that “NO DATA” readings occur, sampling may need to be halted until rain reduces or stops.

Below is a super fancy way of saying “This Instrument doesn’t work in the rain”

Aligning the Instrument Good alignment has peak-

to-peak beam signal strength of 5 to 18 volts.

If the beam strength is too low, accuracy will be compromised.

If the beam strength is too high, peaks may become saturated meaning that the spectral results could display significant peak noise resulting in poor results.

Establishing a Background

“background” is taken and used as reference spectrum for Classical Least Squares processing. In order to properly detect and quantify chemicals present in the atmosphere, the background spectrum must be devoid of all traces of the target chemicals.

background spectrum is always collected as an interferogram - a time-domain waveform produced by the optical path difference of the interferometer. Interferograms can be Co-Added to increase the Signal-to-Noise Ratio of the signal.

Spectra and Concentration Data Study Site 1 – CH4 Release

Concentration Rose Study Site 1 – CH4 Release

Spectra and Concentration Data Study Site 2 – Pilot Test

Spectra and Concentration Data Study Site 2 – Pilot Test

Concentration Rose Study Site 2 – Pilot Test

Phase 2 Field Test Sites

Study site 1 will be a drilling rig

Study site 2 will be an Eagle Ford well pad

Study site 3 will be Eagle Ford processing plants

Develop protocol that includes: OP-FTIR short term and long term monitoring Data control and accuracy Data analysis, concentration rose and plume modeling

Develop Emission Rates from Path Integrated Concentrations

Phase 2 Goals

So in addition to this… We have this…

Logic Mapping for Phase 2

Questions?