Monitoring Methane from Fracking Operations: Leak Detection and Environmental Measurements
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These include methane (CH4) leaks into the ecosystem that occur from leaks in valves and fittings; surface leaks into the groundwater, marshes, and drinking water; and the wastewater from natural gas wells and fracking operations, but we will leave this latter issue for another time. Efforts are being made to decrease CH4 leaks (fugitive emissions) because it a greenhouse gas that is about 30 times more potent than carbon dioxide (CO2).2 The best technique available for part per million (ppm) measurement of CH4 leak detection is a flame ionization detector (FID). We have developed a compact FID with a fast response that is ideal for leak detection. It is the smallest and lightest commercially available FID, and it uses a safe hydride cylinder (H2) for fuel (Figure 2).
hile seeking invited speakers to present at the ACS Presidential Symposium titled “Fracking: Economics vs Environment” in Philadelphia, PA held on August 22, 2016, session organizers Donna Nelson, 2016 ACS President, and Dan Daly, 2016 ACS Multidisciplinary Program Planning Group (MPPG) Chair (Figure 1), invited us, as
Figure 1. Some presenters with organizers at “Fracking: Economics vs Environment” in Philadelphia, PA. L to R: Driscoll, Kleinberg, Nelson, Engel, and Daly. (Photo credit: J. L. Maclachlan.)
instrumentation manufacturers who serve the fracking industry with our environmental monitoring systems, to deliver a talk on our portable analyzers that are “designed to help identify volatile organic compounds (VOCs) in air, water, and soil, atsite in real-time”1 to address the environmental impact perspective of fracking. This is a topic that has interested us over the last several years, and the Philadelphia meeting marks the third occasion where we have been invited to share different aspects of our environmental and process monitoring of fracking operations research with the following ACS division program tracks: Energy and Fuels (ENFL) at ACS San Francisco in 2014; Environmental Chemistry (ENVR) at ACS San Francisco 2014; and this Viewpoint, presented orally, at ACS Philadelphia in 2016 on the Presidential track under the title “Reducing the Environmental Footprint of Methane from Fracking Operations”. The entirety of this session was selected for recording by ACS Presentations on Demand and is available as an ACS member benefit by logging into their system using this link: https://presentations.acs.org/common/presentations. aspx/Fall2016/PRES/PRES012a. There are numerous environmental issues that need to be resolved to make natural gas production a cleaner process. © XXXX American Chemical Society
Figure 2. Expanded view of the Model 115 FID. Graphic provided by PID Analyzers, LLC. Copyright 2013−2017.
An FID consists of a combustion source (a flame), an ion chamber, an igniter, a voltage source for the accelerating electrode, and an electrometer/amplifier. The FID is a masssensitive detector, the output of which is directly proportional to the ratio of the compound’s carbon mass to the total compound mass. It will measure CH4 as well as other hydrocarbons (HCs). The FID can measure HCs from sub ppm levels to percent levels. The specifications for the total HCs and gas chromatography (GC)-based GC/FID analyzers are given in Table 1. We will discuss methods and instrumentation for in-field monitoring (Figure 3) of methane concentrations for fracking operations like detection of fugitive emissions, measuring ppm methane levels in air as a check for finding methane emission Received: July 22, 2017 Accepted: September 13, 2017
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DOI: 10.1021/acsenergylett.7b00645 ACS Energy Lett. 2017, 2, 2436−2439
Viewpoint
http://pubs.acs.org/journal/aelccp
Viewpoint
ACS Energy Letters Table 1. Specifications of FID for Leak Detection and Environmental Measurements specifications range detection limit response time species detected weight
model 115 FID 0−1000 ppm; 0−20 000 ppm 0.1 ppm 7s total hydrocarbons analyzer, 2.2 lb; hydride cylinder, 1.3 lb (belt)
model 121 GC/FID 0−100 ppm; 0−1% 50 ppb 40% by 2025. The new model 121 GC/FID (Figure 9) would be ideal for the modified EPA method for methane and nonmethane HCs. The methane is separated first, then the nonmethane HCs are back-flushed to the FID.
(2) Kelley, M. A More Potent Greenhouse Gas than CO2, Methane Emissions Will Leap as Earth Warms. Research at Princeton, March 16, 2014. (3) Driscoll, J. N. Review of Field Screening Methods for the Analysis of Hydrocarbons in Soils and Groundwater. Int. Labmate. October 1992, 27−32. (4) Kappel, W. M.; Nystrom, E. A. Dissolved Methane in New York Groundwater, 1999−2011. U.S. Geological Survey Open-File Report 2012−1162, 2012; 6 pp. (5) EPA Field Screening Methods Catalogue: Users Guide; EPA/540/288/1005; EPA, Office of Emergency and Remedial Response: Washington, DC, Sept. 1988. (6) EPA. Climate Action Plan: Strategy to Reduce Methane Emissions and the Clean Air Act, Federal Register, June 3, 2016.
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EDITOR'S NOTE Views expressed in this Viewpoint are those of the authors and not necessarily the views of the ACS. Figure 9. Model 121 hand-held portable GC/FID. Graphic provided by PID Analyzers, LLC. Copyright 2016−2017.
Summary and Future Outlook. The GC/FID is very sensitive (0.05 ppm of CH4) and can measure methane in air directly or in water or soil (by headspace). It is an ideal solution for detecting and preventing air and water contamination problems. It can be very beneficial in reducing methane, a greenhouse gas. This method will provide qualitative ppm results for methane for CH4 for soils and water and can also be used to find and fix methane leaks. Model 115 FID measures total HCs and is ideal for leak detection and qualitative surveys looking for environmental issues. Model GC121 analyzes VOCs in a portable GC that can have an FID single column with a fast microcontroller. It is a lightweight, hand-held, battery-operated GC that features data storage of the chromatograms and Bluetooth capability. It has a 3.5 in. color graphics data display. The GC/FID method can detect quantitative sub ppm levels of methane and VOCs in water and soil. A combination of LDAR and environmental monitoring of the air and groundwater−water will help to reduce the environmental footprint of methane and make fracking more environmentally friendly. While the level of environmental regulation enforcement remains to be seen, monitoring programs such as those described herein are examples of energy self-reliance and good stewardship of our planet.
J. N. Driscoll Jennifer Maclachlan
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PID Analyzers, LLC, Sandwich, Massachusetts, United States
AUTHOR INFORMATION
ORCID
Jennifer Maclachlan: 0000-0002-6523-0881 Notes
The authors declare no competing financial interest.
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REFERENCES
(1) Stevenson, R. ACS Addresses Fracking and Sustainability. Am. Lab., October 3, 2014. 2439
DOI: 10.1021/acsenergylett.7b00645 ACS Energy Lett. 2017, 2, 2436−2439
