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ReportDOI

Passive Leak Detection Using Commercial Hydrogen Colorimetric Indicator

TL;DR: DetecTape as mentioned in this paper is a self-adhesive silicone-based tape impregnated with a proprietary hydrogen-sensitive indicator based on transition metal oxides, which is used to detect hydrogen leaks.
Abstract: Element One, Inc. (www.elem.com), a small business with in Boulder, CO, has been developing hydrogen detection technology based upon a highly selective colorimetric indicator. In its native state, the indicator pigment is a pale gray color, but becomes black upon exposure to hydrogen. The colorimetric change can be readily observed by the naked eye without the need for supplemental electronics or other hardware. Recently, the colorimetric indicator was integrated into a pliable, self-adhesive tape that can readily wrap around pneumatic fittings to serve as a hydrogen leak detector. A prototype version of the Element One indicator tape was tested within an NREL hydrogen system and successfully identified the unexpected presence of a small leak; a summary document for this case study is presented in Appendix 1. The tape was subsequently configured into 10-foot rolls as a product prototype that has just recently been commercialized and marketed under the tradename DetecTape(R). Figure 1 shows the commercial version of DetecTape along with an indicator sample in its native state and one that had been exposed to hydrogen. DetecTape is a self-adhesive silicone-based tape impregnated with a proprietary hydrogen-sensitive indicator based on transition metal oxides. A length of the tape can be cutmore » from the roll and stretched by a factor of two or three times around a fitting. Due to the self-adhesive property of the tape, this provides a tight seal around the fitting. The seal is not hermetic, and is not intended to prevent the release of a leaking gas. However, a portion of the hydrogen leaking from a wrapped fitting will pass through the tape and react with the active indicator impregnated within the tape, thereby inducing blackening.« less

Summary (3 min read)

List of Acronyms

  • DetecTape samples deployed on the Gas Management Panel of the NREL Hydrogen Dispenser (A and B) compared to fresh samples (C and D), also known as 17 Figure 19.
  • This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Verification of Indicator Functionality

  • Laboratory testing of DetecTape was performed to demonstrate basic functionality, i.e., to verify the transformation from a pale gray color to black upon exposure to hydrogen.
  • This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.
  • Purge the hydrogen exposure chamber with air at 2 standard liters per minute for 30 to 45 minutes.
  • (The electrical feedthroughs were not needed for DetecTape.).
  • It is noted that this test protocol was used to verify that the indicator would show a visible color change when exposed to hydrogen.

Impact of Environmental Stresses on Indicator Functionality

  • Functionality testing was performed on new indicators and on indicators that were subjected to various pretreatments.
  • Pretreatments included subjecting the indicator to the Environmental Stress Test protocol illustrated in Figure 3 and summarized in Table 1.
  • Humidity is plotted as the dew point (dp) with the corresponding parts per million volume (ppmv) water vapor (H2O), and 4 This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.
  • Following the elevated temperature and humidity exposure test, the remaining indicators (Samples 8 and 9) were removed from the Environmental Test Chamber, transferred to the Hydrogen Exposure Chamber, and subjected to the functionality test described above.
  • This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

DetecTape Deployment in the Open Air

  • DetecTape will readily respond to hydrogen leaking through pneumatic components and when stored in a closed chamber with a uniformly mixed hydrogen atmosphere (e.g., such as those used in the functionality test).
  • No color change was observed after 10 vol% H2 in nitrogen was flowed directly onto the DetecTape surface for 10 minutes in an open system .
  • In a closed environment, the hydrogen will be uniformly mixed, thus minimizing the driving force for dispersion, and as a result will more readily partition into the silicone substrate to react with the indicator.
  • Field Deployment Concurrent laboratory testing, the deployment of over 60 samples of DetecTape on various active hydrogen systems in and around the NREL Energy Systems Integration Facility (ESIF) was initiated.
  • The outdoor sites were mainly associated with the NREL hydrogen fueling station, while the indoor operations included experimental systems within the ESIF high-pressure bays or the indoor water electrolysis system in the Energy Systems Integration Laboratory.

Hydrogen Storage Tanks

  • The NREL onsite hydrogen storage facility consists of three separate hydrogen cylinder storage banks pressurized to 200 bar, 400 bar, and 875 bar.
  • During a cascade fill, hydrogen is drawn from separate storage tanks to better match the pressure of the vehicle tank; this is done to minimize the cost and complexity of pressurization during the fill and is controlled through the Gas Management Panel.
  • The storage tanks and support pneumatic system, shown in Figure 6, are outside and thus exposed to prevailing weather conditions, including rain, snow, and sun, along with the daily and long-term temperature fluctuations.

Gas Management Panel

  • The Gas Management Panel is the interface between the hydrogen storage tanks and the compressor.
  • Access is through two doors, which open to 9.
  • This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.
  • Expose the Gas Management Panel pneumatic system.
  • The cabinet is fully enclosed, thereby protecting tubing and valves from direct exposure to sun, rain, and snow.

Fuel Station Compressor

  • The compressor for the NREL hydrogen fueling station is shown in Figure 8.
  • Components in the compressor cycle between high and low temperatures and pressures.
  • Vibrations, pressure, and temperature fluctuations can stress the integrity of pneumatic fittings and thus can be prone to induce leaks.
  • Furthermore, as an outdoor system, the compressor is in direct contact with environmental conditions such as rain, snow, and sun, as well as daily and seasonal temperature fluctuations.
  • 10 This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Dispenser

  • It consists of a roofless cabinet with two external fueling hoses and internal plumbing.
  • The dispenser is the interface that delivers hydrogen from the storage tank, through the compressor, and into the vehicle.
  • The tubing and components in the dispenser cabinet would be exposed to precipitation and the sun, as well as daily and seasonal temperature fluctuations.
  • 11 This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Indoor Deployment: Component Testing in the ESIF High Pressure Test Bays

  • A core capability of ESIF is the High Pressure Test Bay, which supports experiments and testing of components at elevated pressures.
  • Leaks are a critical concern for high-pressure testing of hydrogen components.
  • The High Pressure Test Bay is an enclosed room with moderate environmental controls to maintain the temperature and relative humidity to around 22°C and 10% to 20%, respectively.
  • One test bay was used for reliability testing of a pressure release device (PRD) [13].
  • DetecTape was placed on pneumatic fittings and valves that were subjected to repeated elevated but controlled pressure variations.

Indoor Deployment: Hydrogen Production in the Energy Systems Integration Laboratory

  • DetecTape was deployed on two components associated with the electrolysis hydrogen production system operating in the ESIF Energy Systems Integration Laboratory.
  • The second indication formed again as a small confined dot over the weep hole of a cone and thread fitting on a valve located in the Gas Management Panel, as shown in Figure 13.
  • 17 This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.
  • In one case, however, the DetecTape clearly identified a hydrogen release on a valve that was out-of-normal (Indication #6).

Stability of DetecTape

  • The first indicator was deployed within this project on July 8, 2015, and additional samples were deployed over the duration of the project.
  • Originally Indication #1 was viewed as out-of-normal, but was subsequently identified as being associated with a normal hydrogen release.
  • To verify the functionality and reliability of DetecTape as a hydrogen leak detector, the NREL sensor laboratory initiated a case study involving both laboratory assessments and actual deployments.
  • U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy.

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Content maybe subject to copyright    Report

NREL is a national laboratory of the U.S. Department of Energy
Office of Energy Efficiency & Renewable Energy
Operated by the Alliance for Sustainable Energy, LLC
This report is available at no cost from the National Renewable Energy
Laboratory (NREL) at www.nrel.gov/publications.
Contract No. DE-AC36-08GO28308
Passive Leak Detection Using
Commercial Hydrogen
Colorimetric Indicator
Kevin Hartmann
, William Buttner,
Robert Burgess
, and Carl Rivkin
Technical Report
NREL/TP-5400-66570
September 2016

NREL is a national laboratory of the U.S. Department of Energy
Office of Energy Efficiency & Renewable Energy
Operated by the Alliance for Sustainable Energy, LLC
This report is available at no cost from the National Renewable Energy
Laboratory (NREL) at www.nrel.gov/publications.
Contract No. DE-AC36-08GO28308
National Renewable Energy Laboratory
15013 Denver West Parkway
Golden, CO 80401
303-275-3000 • www.nrel.gov
Passive Leak Detection Using
Commercial Hydrogen
Colorimetric Indicator
Kevin Hartmann, William Buttner,
Robert Burgess, and Carl Rivkin
Prepared under Task No. HT12.7210
Technical Report
NREL/TP-5400-66570
September 2016

NOTICE
This report was prepared as an account of work sponsored by an agency of the United States government.
Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty,
express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of
any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately
owned rights. Reference herein to any specific commercial product, process, or service by trade name,
trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation,
or favoring by the United States government or any agency thereof. The views and opinions of authors
expressed herein do not necessarily state or reflect those of the United States government or any agency thereof.
This report is available at no cost from the National Renewable Energy
Laboratory (NREL) at www.nrel.gov/publications.
Available electronically at SciTech Connect http:/www.osti.gov/scitech
Available for a processing fee to U.S. Department of Energy
and its contractors, in paper, from:
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Cover Photos by Dennis Schroeder: (left to right) NREL 26173, NREL 18302, NREL 19758, NREL 29642, NREL 19795.
NREL prints on paper that contains recycled content.

iii
This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.
Acknowledgements
Support for this project was provided through the National Renewable Energy Laboratory’s
Commercialization Assistance Program (Sarah Truitt, Manager) and through the U.S.
Department of Energy Office of Energy Efficiency and Renewable Energy Fuel Cell
Technologies Office, Safety Codes and Standards Program (Will James, Program Manager).
Access to the NREL hydrogen facilities was provided by Kevin Harrison, Owen Smith, Daniel
Terlip, Michael Peters, and Josh Martin.

iv
This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.
List of Acronyms
atm atmosphere
dp dew point
ESIF Energy Systems Integration Facility
H
2
hydrogen
H
2
O water
NREL National Renewable Energy Laboratory
ppm
v
parts per million by volume
PRD pressure release device
RH relative humidity
T temperature
vol% percent by volume

Citations
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Patent
Nakamura Koichi1, Mohajeri Nahid, Chen Yu Chu1, Bizati Kujtim1, Shinji Inokuchi1 
16 Feb 2018
TL;DR: In this paper, a gas sensing element includes a gas detection layer including a chemochromic pigment, with modifications towards enhancing shelf-life performance and false detection performance before use, and methods of making the afore-described element to attain enhanced shelf life performance.
Abstract: A gas sensing element includes a gas detection layer including a chemochromic pigment, with modifications towards enhancing shelf-life performance and false detection performance before use. The gas detection layer has an adhesion of greater than or equal to 0.2 N/25 mm. Also described are methods of making the aforedescribed element to attain enhanced shelf-life performance and false detection performance.

1 citations

ReportDOI
01 Jan 2014
TL;DR: In this article, an automated robot mimics fueling action to test hydrogen hoses for durability in real-world conditions, and the results showed that the hoses were durable in real world conditions.
Abstract: Automated robot mimics fueling action to test hydrogen hoses for durability in real-world conditions.

1 citations

Patent
02 Jan 2020
TL;DR: In this paper, a color change ΔL* of a gas sensing element is greater than or equal to 5 when reducing gas causes the sensing element to change in color, where ΔL * is the number of times the gas detection element is changed in color.
Abstract: A gas sensing element includes a gas detection layer including a pigment, the gas detection layer including a first surface; and a backing material disposed on the first surface of the gas detection layer. When reducing gas causes the gas sensing element to change in color, a color change ΔL* of the gas sensing element is greater than or equal to 5.
Journal ArticleDOI
TL;DR: An overview of metal-hydride-based hydrogen sensors and evaluates their potential for utilization in aerospace safety applications in future hydrogen-powered aviation is presented in this article , where specific performance parameters for hydrogen sensors are identified.
Abstract: This paper presents an overview of metal-hydride-based hydrogen sensors and evaluates their potential for utilization in aerospace safety applications in future hydrogen-powered aviation. The ‘electrical resistance’, ‘cantilever expansion’, ‘nanogap expansion’, ‘fiber optical’, ‘chemochromic optical’ and ‘acoustic’ sensing principles are being described. Requirements including specific performance parameters for hydrogen sensors in aerospace safety applications are identified. Evaluation criteria are derived from these requirements and finally the sensing mechanisms are evaluated by means of a weighted point rating. The results of this evaluation reveal the high potential of ‘electrical resistance’, ‘cantilever expansion’, ‘nanogap expansion’ and ‘fiber optical’ sensors, although none of these principles meets all the requirements yet. With the transition to hydrogen-based aviation, metal hydrides and its various applications will become more attractive. Synergies between these technologies may further drive the research and development progress, so that metal-hydride-based hydrogen sensors can overcome their current drawbacks and contribute to the transition to future hydrogen-powered sustainable aviation.
References
More filters
DOI
01 Jan 2003
TL;DR: The International Organization for Standardization (ISO) is a non-governmental federation of national standards bodies from 157 countries worldwide, one from each country as discussed by the authors, whose work results in international agreements which are published as International Standards.
Abstract: Established in 1947, the International Organization for Standardization is a non-governmental federation of national standards bodies from 157 countries worldwide, one from each country. ISO’s work results in international agreements which are published as International Standards. The first ISO standard was published in 1951 with the title ‘Standard reference temperature for industrial length measurement’.

3,009 citations

ReportDOI
01 Jan 2014
TL;DR: In this article, an automated robot mimics fueling action to test hydrogen hoses for durability in real-world conditions, and the results showed that the hoses were durable in real world conditions.
Abstract: Automated robot mimics fueling action to test hydrogen hoses for durability in real-world conditions.

1 citations


Additional excerpts

  • ...Benson, D.K., W. Hoagland, R. Smith, and W. Buttner 2013....

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