Application Notes

What is hydrogen?

Hydrogen (H) is the first element on the periodic table and is the most abundant gas in the known universe. Each atom of hydrogen consists of only one proton. Despite this, there is no natural hydrogen produced on Earth as it is only found in a combined form. Water (H2O), for example, is a combination of hydrogen and oxygen. Hydrogen is also found in other forms such as hydrocarbons which are contained within fuels such as petrol, diesel, natural gasses, methanol, and propane.

Hydrogen is not actually an energy source itself, but instead an energy carrier. For this reason, hydrogen has a unique and often, at times, misunderstood role in the global energy system. One of the most significant advantages of hydrogen is that it is very efficient, approximately three times more efficient than gasoline.

One of the biggest challenges with hydrogen is obtaining it in its pure form.  Although Hydrogen is a green fuel during its usage, cracking hydrogen from its compound form requires a large amount of energy. At the current time, around 84% of the world’s energy is still derived from fossil fuels. This results in greenhouse gas emissions and air pollutants which lessen the overall environmental benefits of hydrogen power. There is also still the issue of safely storing and transporting this volatile element. There are however many schemes and government directives that are pushing for more and more renewable energy as well as ongoing projects within various companies to develop safer ways of transporting and using hydrogen. Along with a greener energy source, we are also able to produce hydrogen from biological hydrogen production, a process where carbohydrate-rich and non-toxic raw materials are broken down by anaerobic and photosynthetic microorganisms, producing hydrogen as a byproduct of this process.

Hydrogen as a form of energy carrier is not new,  powering the first internal combustion engines over 200 years ago and becoming a fundamental part of the refining industry. It has some positive benefits being light, storable, energy-dense and only having water as a by-product. Hydrogen could be the key to unlocking a carbon-neutral future. However, for this to happen it needs to be adopted into the larger industries and sectors where fossil fuels and nuclear energy are currently being used such as transport, buildings and power generation.

Can hydrogen be used as a fuel for vehicles?

A fuel cell is an electrochemical cell, that produces electricity by converting chemical energy into electrical energy. When hydrogen and oxygen are combined within a fuel cell, heat and electricity are produced, with water vapour produced as a by-product.

Fuel cells have the potential to power electric motors (used within various modes of transportation),  provide energy for systems as large as a power station or charge something as small as a mobile phone.

As with battery-electric vehicles (BEV), hydrogen fuel cell electric vehicles (FCEVs), including cars, vans, buses and lorries are powered by electricity, so produce no harmful emissions including carbon dioxide (CO2) from their tailpipe. Only water vapour is produced from hydrogen fuel cell electric vehicles. In FCEVs, energy is stored in the form of compressed hydrogen fuel, rather than in a battery. Hydrogen can be stored and transported at high energy density in liquid or gaseous form.

In hydrogen fuel cell electric vehicles (FCEVs) the fuel cell converts compressed hydrogen from their fuel tanks into electricity that powers the electric motor in the vehicle.

A fuel cell coupled with an electric motor is two to three times more efficient than an internal combustion engine running on gasoline. Therefore FCEVs have the advantage of being able to cover longer distances, and only take a few minutes to refuel at a retail site, unlike BEVs that take a long time to recharge in comparison with a much shorter range.

Pressure sensors for hydrogen applications

With the demand for hydrogen fuel cell-powered vehicles and equipment increasing, so does the need for hydrogen-compatible equipment and components. Core Sensors, a leading manufacturer of pressure and temperature transducers, produce a range of specialist pressure sensors capable of monitoring the dispensing and storage of hydrogen.

Hydrogen embrittlement is the degradation of a sensor diaphragm’s metal properties caused by hydrogen. To avoid this, choose the optimum sensor materials. Materials to avoid are 17-4 stainless steel and nickel-based alloys like Inconel 718.

There are some known difficulties when working with hydrogen in its gas form, so selecting the correct sensor configuration is a key factor in the planning process. Two of the biggest concerns are hydrogen embrittlement and hydrogen permeation.

Hydrogen permeation happens when hydrogen atoms (H2) separate into hydrogen ions (H+) under specific conditions like high pressure and temperature. These hydrogen ions can pass through the sensor diaphragm’s molecular structure.

To overcome these complications, Core Sensors have designed a range of pressure sensors, transducers and transmitters, providing a high-quality and long-life solution for your hydrogen application.

Design & Materials selection

Fluid filled sensor diaphragms are highly susceptible to hydrogen permeation and should be avoided. Hydrogen ions that pass through the thin diaphragm will form hydrogen bubbles in the fill fluid causing zero and span shifts. Over time these bubbles can expand and cause the diaphragm to bulge and eventually fail, resulting in the fill fluid leaking and contaminating the process.

To avoid having fluid filled cavities, sealing materials such as O-rings or welded joints, Core Sensors can manufacture their sensors using a single piece of 316L stainless steel. This solid piece of stainless steel then contains the hydrogen within the pressure port, reducing the possibility of the media permeating the thin diaphragms that are common in oil filled sensor designs.

High-pressure hydrogen measurement

Hydrogen is compressed to a high pressure, typically 350 Bar (~5,000 PSI) and 700 Bar (~10,000 PSI), to help increase the amount of hydrogen that can be stored on site. Highly reliable pressure sensors are required to safely monitor these tanks and other high pressure hydrogen applications. Core Sensors offer an F250C female autoclave process connection option for pressures >10,000 PSI. This process connection features all 304 and 316L stainless steel wetted parts to ensure protection from embrittlement and permeation, resulting in a long term monitoring solution.

Applications
  • Storage
  • Fuel Lines
  • Dispensers
Benefits
  • High Strength
  • 316L Stainless Steel
    UNS S31603
  • All welded metal construction
    No internal elastomer seals
  • Area Classification
    CSA Class I, Division 2 Non-Incendive Groups A, B, C, D T4
  • Marine ABS Approvals
  • CE
CS50 with an F250C Female Autoclave process connection and Mini-Fast electrical connection
CS50 with an F250C Female Autoclave process connection and 1/2″ MNPT conduit w/ cable
F250C Female Autoclave process connection in all 304 & 316L SS

Industrial applications

For industrial applications where hazardous certification approvals are not required, the CS10 Industrial Pressure Transducer can be packaged to meet the demands of hydrogen environments. Pressure ranges are available from 50 PSI up to 20,000 PSI in solid 316L SS. Customers have the choice of various output signals including 4-20mA loop powered for long-distance transmissions and voltage outputs for low power and low current consumption applications. A variety of electrical connections are available from standard DIN connections to M12x1 and integral cable for a higher IP67 rating. Custom configurations are available for OEM projects.

Hazardous – Non-incendive

Some applications require non-incendive approved equipment, the CS50 Non-Incendive Pressure Transducer is an ideal solution to this and can be configured with 316L stainless steel material and various other options. The CS50 is approved for the following standards:

  • CSA Class I, Division 2, Groups A, B, C, D T4
  • ANSI/UL 122701 Single Seal
  • ABS (American Bureau of Shipping)
  • CE

Common model number configurations

To best suit your application and installation requirements, Core Sensors are able to customise the configuration of the below parts that are typically used in hydrogen fuel cell applications.

Model NumberDescriptionTypical Use
CS10-GA00020BG2C000-00
View CS10 specifications
0-20 Bar, 3/8-24 UNF-2A Male process connection, 0.5-4.5V ratiometric output signal (5VDC regulated power supply), Packard Metripack 150, 316L SS wetted material, GaugePost regulator pressure into PEM (Proton Exchange Membrane)
CS10-4A00020BG2C000-00
View CS10 specifications
0-20 Bar, 7/16-20 UNF Male process connection, 0.5-4.5V ratiometric output signal (5VDC regulated power supply), Packard Metripack 150, 316L SS wetted material, Gauge Post regulator pressure into PEM (Proton Exchange Membrane)
CS10-GA00448BS2C000-00
View CS10 specifications
0-448 Bar, 3/8-24 UNF-2A Male process connection, 0.5-4.5V ratiometric output signal (5VDC regulated power supply), Packard Metripack 150, 316L SS wetted material, Sealed GaugeHigh pressure Hydrogen storage
CS10-4A00448BS2C000-00
View CS10 specifications
0-448 Bar, 7/16-20 UNF Male process connection, 0.5-4.5V ratiometric output signal (5VDC regulated power supply), Packard Metripack 150, 316L SS wetted material, Sealed Gauge High pressure Hydrogen storage

References

Hydrogen. (n.d.). Shell. https://www.shell.com/energy-and-innovation/new-energies/hydrogen.html

Hydrogen. (2022). Student Energy. https://studentenergy.org/source/hydrogen/

Hydrogen Pressure Sensors – Industrial & Hazardous. (n.d.). Core Sensors. https://core-sensors.com/hydrogen-pressure-sensors/