Companies around the world are using hydrogen blended with natural gas to reduce the amount of carbon output or the greenhouse gas emissions that come from the combustion of hydrogen. The question this brings is: Can the current flow meters handle this without the need to redo the whole pipelines’ infrastructure and their measurement stations? 

We invited Martin Schlebach, Senior Director of Business Development - Flow Consultant for Emerson to answer this and other questions regarding the nuanced dynamics of mixed gas flows.

Q: What are the current limitations for using current meters with higher hydrogen blends?

A: There are two main limitations: Electrical approvals and gas velocity. Current ultrasonic meters might not have the necessary electrical certifications for environments with higher hydrogen concentrations. These certifications ensure the meter's electrical components can operate safely in the presence of hydrogen, which can be more flammable than natural gas. Regarding gas velocity, to deliver the same amount of energy with a higher hydrogen blend, the gas velocity needs to increase significantly 4 to 5 times compared to natural gas since hydrogen has a lower energy density than natural gas. Current pipelines are designed to handle the flow rate of natural gas, but the higher velocity required for hydrogen blends can cause issues with piping infrastructure.

Q: Does that mean current natural gas meters can’t handle a blend of hydrogen and natural gas?

A: It depends on the type of meter and the hydrogen concentration. Ultrasonic meters, a common type of meter used in natural gas applications, can handle up to about 20-30% hydrogen by volume while maintaining a reliable level of accuracy. Their functionality relies on the transit time measurements in the gas to measure flow. Hydrogen has a different transit time compared to natural gas, so the meter's calibration needs to be adjusted for the blend. The blending of hydrogen has become a big question, and a lot of the end users that we've had in the past have bought thousands of ultrasonic meters that are currently in use today.

Q: So, is there a current need to completely replace the pipeline infrastructure for hydrogen blending?

A: Not for lower blends. In cases up to around 20% of added Hydrogen, the global existing infrastructure can likely handle the slightly increased velocity. However, for very high hydrogen concentrations, significant infrastructure modifications might be needed. This could involve upgrading existing pipelines or replacing them completely depending on the case.

Q: What is Emerson doing to prepare for the hydrogen era?

A: Emerson is proactively preparing for the transition to hydrogen by testing and improving our products to ensure a reliable performance in hydrogen blending applications. Within our Measurement Instrumentation team, we've participated in several Joint Industry Projects in which the Rosemount™ SeniorSonic 3414 and 3418 Gas Ultrasonic Flow Meter were tested by having hydrogen progressively being added to natural gas. Hydrogen was added in 5% increments all the way to 30% without compromising the performance of the meters. So, 30% is the level of electrical approvals we have at this point, which is already remarkable. We are working to obtain the necessary electrical approvals for our Rosemount Ultrasonic meters to handle higher hydrogen concentrations up to 100% and are researching ways to improve the meter's accuracy for a wider range of hydrogen blends.

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