A New Era in
Hydrogen Detection...
Now there’s a better way to positively indicate
the presence of hydrogen.
Element One’s low-cost visual indicators and wireless sensors can:
• Improve plant safety, efficiency and productivity
• Minimize down time by quickly detecting and showing the location of gas leaks for faster repair Element One has developed and patented a unique
family of hydrogen and hazardous gas sensing technologies that form the basis for a wide array of low
cost, reliable gas detection systems. The hydrogen
systems are based on a simple chemochromic hydrogen detector that visually indicates the presence–
or absence–of hydrogen.
Because of their low cost, Element One’s visual indicators and wireless sensors can be abundantly deployed to detect leaks at the source to complement
conventional electronic detection systems.
This technology, developed under a cooperative effort with the National Renewable Energy Laboratory,
incorporates either thin films or particles of transition
metal oxides with a very thin, discontinuous coating of a catalyst to create materials that dramatically
change color in the presence of gaseous hydrogen.
Indicating paints and specialty coatings, inks, marking
pens, indicating tapes, stretch films, shrink wrap, and low
cost RFID wireless sensors are just a few of the numerous
products made possible by Element One’s technologies.
In addition to our core patent (US 6,895,805), Element One has additional patents pending for:
• Conformable hydrogen indicating wraps (Thin Films)
• Hydrogen indicating pigments (Coatings)
• RFID hydrogen gas sensors (Wireless)
Element One is continuing to improve and test the
performance of several prototypical products based
on these patents, and will soon have products ready
for commercial testing and market introduction. A
summary of progress to date for each follows.
Thin Films
Gas On
Gas Off
The indicator rapidly begins to reverse when the hydrogen
gas is shut off. A video showing the rapid color change
can be seen at www.elem1.com/technology.htm.
Element One’s thin films may be applied on virtually any substrate, including stretch and shrink films
to make indicating wraps and tapes to encapsulate
tanks, equipment, fittings and valves monitoring for
hydrogen at the most likely leak sites. For selected
applications, the film could be deposited in the form
of symbols or words that would appear when ex-
posed to hydrogen, making leaks or flammable mixtures readily recognized by the untrained eye.
Applications include coatings for protective gear,
equipment, piping and valves, storage tanks, vehicles, stationary appliances, connectors, refueling
stations or in closed spaces such as garages.
Coatings
Element One’s hydrogen indicating pigments are the
only available coatings for the detection of hydrogen
that change color, either reversibly or non reversibly
as desired, to give both current and historical information about leaked hydrogen.
Fig. 1 Immediately after coloring the reversible
paint samples. The bottom irreversible sample
was exposed in the center spot two weeks earlier.
Particles of transition metal oxides can be used as
pigments in indicating paints and printing inks. Coatings may be applied with a brush, spray can, paint or
marking pen, or used to coat decals or tape that may
be affixed wherever a leak might occur.
In a round of environmental applications testing at
the NASA/Kennedy Space Center corrosion test facility in Florida, our thin film samples performed extremely well.
Fig. 2 After 1.8 hours.
Visual Indicators with Adjustable Recovery
Times
Element One is developing films and pigments that
could be applied as dots of chemochromic material,
each having different properties that would change
back to normal coloration at varying rates. One
dot could react rapidly while others could revert at
varying rates to provide historical information over
a period of minutes or hours. Such decals could be
placed on the inside of fuel doors on vehicles, worn
as badges, or placed anywhere an indication of the
presence of leaked hydrogen is needed.
Figures 1 through 3 illustrate the adjustable recovery time that can be built into coatings. The pair
of samples in the upper right are the fastest. The
one horizontal sample at the bottom of each figure
with the dark spot is essentially irreversible. The
exposed spot will remain dark for weeks. This customizable response is also applicable to thin films.
Figure 4 shows the rate of change of the pigment in
the paint.
Fig 4. Rate of Change
Fig. 3 After 16 hours.
Element One’s Technology
Our visual hydrogen gas indicators use thin films
or particles of a transition metal oxide. A very thin
coating of a catalyst is applied to the transition
metal oxide to catalyze its reaction with hydrogen.
Thin Films
A typical thin film indicator consists of a transparent
polymer substrate, a 500 nm thick layer of tungsten oxide, a 3 nm layer of palladium catalyst, and
a 100 nm thick protective coating of poly-tetrafluoroethylene (PTFE). The tungsten oxide layer is
nano-porous. The semitransparent catalyst layer
is discontinuous, consisting of nano-scale islands
on top of the tungsten oxide. The very thin PTFE
partially protects the catalyst from poisoning by atmospheric pollutants. It also tends to stabilize the
thin film stack against abrasion by providing a low
friction surface. All of the layers are deposited by
thermal vaporization in vacuum.
Wireless
Typical Structure of
Chemochromic Indicator Material
PTFE 100 nm
Palladium 3 nm
Tungsten oxide 500 nm
Substrate polymer sheet
Tungsten oxide
powder
Platinized chemically
Vacuum
deposited
multi-layer
thin film
Chemically
synthesized
particles
Particles
Particles of transition metal oxides are coated with
a partial layer of catalyst by conventional chemical
techniques. These particles can be used as pigments in indicating paints and printing inks.
Wireless Sensor
In addition to coating and thin films, Element One
has developed another family of products that use
Radio Frequency Identification Devices (RFID), and
completed initial development of an RFID-based hydrogen sensor that can be deployed abundantly in
hydrogen plants and distribution facilities. The sensor prototypes could be integrated into a new generation of RFID “Smart Tags” that will store and transmit
information about hydrogen leaks.
Integration of these sensors into a network will provide a low cost, effective system for monitoring for
leaks. In such a network of perhaps hundreds of
sensors, each RFID tag may be interrogated as often as once every second.
The resistance of the Element One RFID Sensor Prototype changes from above 60 mega-ohms to less than
60 kilo-ohms when hydrogen is detected.
With further development, these RFID tags may
have the capability to also give information about the
magnitude as well as the existence of a leak. This
information will be invaluable to plant safety and
maintenance personnel in assessing whether a process must be shut down immediately or to continue
monitoring and schedule a repair at the next opportunity.
“Although safety-by-design and passive mitigation systems are preferred, it will still be necessary to develop technologies to detect hydrogen releases or other system failures. For
example, coatings that change color upon
exposure to hydrogen can provide immediate visual evidence of a leak.”
A Recognized Need
U.S. DOE Multi-Year Plan 2003-2010
Market Advantages/Customer
Benefits of
Visual Hydrogen Indicators
√ Visible - convenient indication from a
distance
√ Inherently safe - no electronics
√ Reversible or non-reversible versions
√ Simple - No instrumentation needed
√ Convenient, Very Low cost
√ Flexible - Applicable in various forms
• Paint
• Decals
• Conformable wraps and tapes
√ Selective - detects hydrogen only
√ Sensitive to hydrogen - 1/100 of lower
flammability limit.
√ Positive indication of both presence or
absence of H2
√ Suitable for Low-cost Wireless Sensors
Better Than Typical Detection
Systems
Detection systems must ultimately trigger one or
more of the human senses (sight, smell, hearing,
taste, and touch). This is why odorants are added to
natural gas pipelines. A typical hydrogen detection
system is comprised of a sensor, transducer, and
another device such as a bell, buzzer or light to be
detected by one or more human senses.
Existing hydrogen gas sensors may be too large,
too immobile, too complex, or too expensive for
widespread use. Mass spectrometers and chromatographs, for example, are extremely sensitive,
but are also large, immobile, expensive, require
skilled operators, and may have long response
times. Portable detection devices are too expensive for the wide area coverage that can be economically obtained using the new visual indicator.
While many of these methods perform well under certain conditions, most require electrical
power with its attendant hazard of an electrical
fault causing ignition of an explosive mixture, and
none meets all of the criteria for all applications.
About Element One, Inc.
Element One, Inc. is based in Boulder, Colorado.
The company was formed to develop and market
new low-cost hydrogen indicators based on new
patented and proprietary technologies that use
chemochromic materials and newly developed fabrication techniques as the basis for a wide array of
low-cost, wide area hazardous gas indicators. Sensors for hydrogen sulfide, ammonia, and chlorine
gas are also under development.
Element One is currently seeking additional development partners to participate in the testing and
product development of new products for safely and
reliably monitoring systems for the detection of hydrogen leaks and hazardous mixtures of hydrogen
in air. If you have a requirement and would like to
discuss specific products and applications, contact:
William Hoagland
(720) 222-3214
[email protected]
Copies of technical papers and
presentations are available
on our web site:
www.elem1.com
Element One, Inc.
7253 Siena Way
Boulder, CO 80301
720.222.3214