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Hydrogen Blending

Hydrogen and Natural Gas Blending during Energy Transition Phases

Operators worldwide are looking at and implementing hydrogen blending into existing natural gas infrastructure to reduce carbon emissions.

The introduction of hydrogen into natural gas transportation and distribution networks changes the composition of the stream. Higher volumes of gas must be transported in order to achieve the same BTUs or calorific values provided by pure natural gas. As the percentages of hydrogen blending rise, the energy calorific value of the natural gas decreases. As a result, an increased amount of gas in volume must be consumed to meet the required energy needs of appliances, vehicles, etc.

Furthermore, many regions intend to utilize existing infrastructure for a quick and economical transition. Metering instrumentation should therefore be able to cope with constant compositional changes and avoid pressure drops across the network at all costs.


Hydrogen Flow Metering Applications:

1. Green Hydrogen: Pure hydrogen produced from renewable resources such as wind and solar and after electrolysis is completed offshore or onshore
2. Blue Hydrogen: Hydrogen produced as a by-product from fossil fuel resources (steam reforming)
3. Mixed with Fossil Fuel: Combination of blue or green hydrogen used to reduce current carbon emissions


How is Hydrogen Transported and Distributed in Natural Gas Networks

There are three possible ways of getting hydrogen to end-users and markets:

  • Transportation in compressed cylinders or cryogenic liquid tankers.
  • Distribution via dedicated pipelines.
  • Blended into existing natural gas infrastructure. This, however, lowers the amounts of hydrogen that can be mixed into the natural gas to ensure the integrity of the existing infrastructure. In most cases, operators around the world are looking to achieve a maximum of 20% to 30% by volume. Recent studies show that this is based on what the current infrastructure can tolerate.


What is FLEXIM’s approach to this market?

Our expertise and track record in measuring natural gas, pure hydrogen, and steam are already areas in which FLEXIM’s gas meters provide high accuracy and reliability. Our flowmeters prove to have numerous benefits and can be installed in many points of the process.  

FLEXIM’s R&D department engaged in a Joint Industry Project (JIP) at the DNV GL laboratory earlier this year. This was to ensure the suitability and applicability of our technology on the transportation and distribution side of the industry. The performance and capabilities of our clamp-on G721 & G722 ultrasonic gas flowmeters were tested against traditional inline meters in natural gas and hydrogen blends up to 20% in volume.

The results of these tests show that FLEXIM’s non-invasive flowmeters can measure hydrogen and natural gas blends. It was also shown that the performance and accuracy of FLEXIM’s technology are not affected by the changes in composition presented by these mixes. 

FLEXIM’s gas flowmeters use state-of-the-art processing and analytic algorithms to track changes in acoustic velocity, gas compressibility, and molecular weight dynamically via the NGE (Natural Gas Engine).  While many other ultrasonic technologies rely on gas chromatography to convert actual to standard volumes, FLEXIM developed the NGE to calculate the Z-factor and molecular weight directly within the meter. This tracks compositional changes within the stream which is of particular benefit in hydrogen and natural gas blended streams. 

A few key takeaways from this engagement that were confirmed by the Joint Industry Project (JIP) are:

  • Blended mixtures of natural gas, hydrogen, and CO2 up to 20% have no significant impact on the performance of FLEXIM’s gas meters.
  • The measurement uncertainty will be within our gas specifications of +/-2%.
  • Our NGE functionality is a key feature to measure blended gas streams accurately and calculate the calorific value of the mixed stream.

Our repeatability in mixed streams remains at below 0.15%.

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