Water Electrolysis for
Hydrogen Production

Ensuring Process Safety and Product Quality
Using Oxygen, Hydrogen, and Moisture Analyzers

Electrolyzer by-products include water vapor and oxygen. Precise measurements of hydrogen,oxygen and moisture content can provide an index of the efficiency of the electrolyzer. Maximizing anelectrolyzer’s safety and efficiency requires highly reliable and accurate sensor technology.
As a recognized leader in process analyzers, Panametrics offers a complete system for hydrogen, oxygenand moisture measurement for water electrolysis.

Hydrogen: The fuel of the futureHydrogen measurement

Developments in recent years to reduce greenhouse gases have prompted many countries to achievea net-zero target by 2050. To achieve these goals, these countries seek to maximize energy sources thatminimize emissions. Hydrogen as a fuel offers one such path.

Hydrogen is highly flammable and can react
explosively with oxygen. It is important to know
if the oxygen content approaches the lower
explosive limit in the hydrogen stream, due to any
leaks or membrane cross-over.

Hydrogen, a versatile energy carrier, doesn’t produce carbon emissions, such as CO and CO2, whenburned. Also, when it’s produced in a climate-friendly manner, hydrogen significantly contributes toreducing CO2 emissions in industry and transportation. As such, it will play a vital role in the success ofthe global energy transition.
One process that will make a major contribution to this effort is hydrogen production via waterelectrolysis, using renewable energy to power the process. The hydrogen produced in this way is called“green hydrogen.”

It is also critical to continuously monitor forleaks on the oxygen and hydrogen side of theelectrolysis cell, so that this does not approachthe explosive limit of the gas mixture. This safetyrelevant measurement indicates the health of theoverall process and efficiency of the membrane.
It always should be done with reliable, robust andproven technology.

Further processing

Panametrics XMTCO2 Outlet

O2

H2H2O

H2O

H2 ProductDryer

To consumer

Reliable and accurate analysis of hydrogen concentration in a compact, robust package.

H2 Outlet

O2+

H2Electrolyser-% H2 in O2% O2 in H2
ppm O2 in H2
ppmv H2O in H2Electric PowerThe Panametrics XMTC Thermal Conductivity Binary Gas Analyzer reliably monitors hydrogen in oxygenand oxygen in hydrogen. Typical measurement ranges are 0 to 5% to signal a membrane malfunction.
The XMTC is certified for Class 1/Zone 1 environments.

WaterBenefits• Proven technology in a a simple, easy-to-use, compact design reduces system solution costs•R ugged constructionand no moving parts means extremely stable output with real-time error detection• Doesn’t require frequent field calibration• Basically maintenance free by design• Stands up to harsh environments, withstanding shock and vibration

Typical Electrolyser Process

Water electrolysis
An electroyzer passes an electrical current to split water molecules into hydrogen and oxygen. The cell,
the core of the electrolyzer where this process takes place, features two electrodes. The electrodes are
immersed in an electrolyte separated by a membrane. Water splits into oxygen and hydrogen at theelectrodes, while the membrane separates these produced gasses.

Key features• Weather- and explosion-proof versions• Extremely stable measurement thermistors• Button-activated calibration• PC interfaces for digital output• Standard and custom calibration ranges between 0% and 100%

The membrane keeps these two gases separate during the splitting process, moving the oxygen to its
own outlet. Crossovers of these gases on the membrane may occur, however.
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Trace oxygen analysis
The hydrogen produced during
electrolysis typically contains
high levels of moisture andvarying amounts of oxygen.
This moisture and oxygen areremoved to produce high purity
hydrogen. This is necessary tomeet gas quality specifications

Trace moisturemeasurement

for compressed hydrogen in applications such asfueling stations.

In most electrolyzer
applications, the exit gases
are saturated with water.
Since water vapor doesn’tburn or carry energy,
dehydration is necessary
to effectively transport,
store and use the hydrogenproduced during electrolysis.

Reliable oxygen measurement in a compact,
unique design.

Intrinsically safe, moisture transmitter general
purpose and hazardous area use.

Panametrics oxy.IQ galvanic cell transmitter
detects the lowest possible oxygen impurities
in the hydrogen stream, delivering 17 different
percentage and ppm measuring ranges. It delivers
reliable measurement in a compact design.

Panametrics was founded in 1960 with theintroduction of the patented thin-film, aluminumoxide moisture sensor. Today, we use thistechnology in the intrinsically safe and highly
versatile HygroProII transmitter. The HygroProII
combines moisture measurement with builtin temperature and pressure sensors to meetthe demands of rugged industrial applications,including hydrogen production.

Benefits•P roven galvanic fuel cell sensor technology
provides superior performance, accuracy,
stability and long life• Compact analyzer design provides easy
installation and system solution flexibility• Innovative design eliminates the potential
for negative signal output, reduces sourcesof contamination• Built-in microprocessor with intuitive userinterface to easily select range, trim outputs
and perform calibration• User-selectable ranges, calibration, sensor
diagnostics with keypad simplifies programming•B ackground gas insensitivity and acid gas sensor
options ensure accurate measurement and analysis

Key features• Display with keypad, user interface withdiagnosis function• Sensor-failure and lifetime monitoring features• User-programmable, low maintenance,economical, compact•W ide range of different calibrations covering
ppm and % O2 rangesBenefits• Compact transmitter with moisture, temperature,and pressure sensors mounted on a single probe
allows installation where space is at a premium.
• Measurements at pressures up to5000 psig (345 bar)
• Large dynamic dew/frost point measurement
range (-110 °C to +60 °C)• Sensors are easy to replace in the field

Key features• Intrinsically safe
• Ambient to ppb moisture levels using aluminium
oxide moisture sensor• Built-in temperature and pressure sensors• Integrated display/user interface• HART communication overthe 4 – 20 mA analog output5Industrial moisture transmitter

Turnkey measurement solutions

Features & benefits

The DewPro Moisture Transmitter is an ideal,
low-cost, explosion-proof moisture transmitterfor the dryer application in water electrolysis.

Any analyzer’s performance depends on thesample system integrity. Panametrics pro.IQ andO2.IQ, are complete plug-and-play systems,
delivering moisture and oxygen measurements
every time. Simply mount the transmitter, connect
power and inlet gas, and the analyzers are readyfor use.

• Package design provides easy access totransmitter for effortless maintenanceBenefits• Provides long calibration stability andquick response times• MMY30’s integral flow cell for filtrationand flow regulation is ideal for moisturemonitoring in various process environments

Key features• Compact footprint, stainless-steel package andloop-powered transmitters provide solutions thatwork in safe and hazardous areas• Wall-mounted NEMA 4X and IP66 stainlesssteel package• The sample conditioning system provides
isolation, filtration, pressure regulation, flow andpressure indication along with a clear window foreasy viewing of all readings• Loop powered, 4-20mA transmitter• Integral filtering and flow regulation• Hazardous area configurations available

67

Panametrics, a Baker Hughes Business,
provides solutions inthe toughest applications
and environments for moisture, oxygen, liquidand gas flow measurement. Experts in flaremanagement, Panametrics technology also reduces
flare emissions and optimizes performance.
With a reach that extends across the globe,
Panametrics’ critical measurement solutionsand flare emissions management are enablingcustomers to drive efficiency and achieve carbon
reduction targets across critical industries
including: Oil & Gas; Energy; Healthcare; Water
andWastewater; Chemical Processing;Food & Beverage and many others.
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For us, it is safety first! The criticalmeasurement is hydrogen in oxygen,to ensure that we do not have leakage
from the high-pressure hydrogen to
the low-pressure oxygen side of themembrane. Oxygen can […] get below
the upper explosive limit resulting in asafety issue. The other measurements
are concerns for our customers whouse the hydrogen. As an example,
there are gas quality specifications
for moisture in the compressedhydrogen in a fueling station.
– Electrolyzer Manufacturer

Contact us

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panametrics.com

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