Delivering Hydrogen to Consumers Where and When it is Needed

In a Global Hydrogen Review article, Emerson’s Laura Chemler examines what new hydrogen infrastructure will look like.

As the world looks to hydrogen as an alternative fuel, we must address transportation challenges in addition to production and utilization challenges.

Historically, hydrogen production and utilization happen within a refinery, ammonia synthesis plant, or chemical plant. There are some exceptions to this, the most notable being the US Gulf coast where a hydrogen pipeline has existed for decades between producers and users. Today, the use-case of hydrogen is expanding to where hydrogen production is not always located near hydrogen utilization.

This poses the question of how to transport the hydrogen to where it’s needed, when it’s needed, all while maintaining high levels of operational safety, reliability, efficiency, and accountability. While a lot of the hydrogen market feels new, we must remember we have the experiences of refineries and natural gas infrastructure to build upon and learn from. Hydrogen transportation from production sites to offtakers is the focus of my article in Global Hydrogen Review, The Evolving Future of Hydrogen Transport.

When looking at the transportation possibilities, it is important to keep volume demands and transport distance in mind. There are costs associated with every method, but these factors will make the difference between practical and impractical when determining which solution makes the most sense for your application.

Liquid hydrogen will offer the highest energy density, but at a significant energy cost. This cost begins to pay off for longer distances since hydrogen is easier to transport once liquified.  Specially designed tube trailers can be utilized for land transport, while specially designed marine tankers can transport liquid hydrogen across oceans.

Compressed hydrogen can be moved in hydrogen tube trailers, which can also be utilized as storage onsite. Depending on the type of cylinder, you can expect ranges around 180 bar to 750 bar or higher. Tube trailers are a fixed volume of 500 kilos per trailer, but offer the most flexibility when it comes to responding to customer demands. The truck loading and unloading process is an important metering point for accuracy and safety.

Hydrogen truck loading and unloading sites are critical metering point for quantity verification. These sites require particular attention to leaks and fires since transfer connections will be made and broken many times each day.

A direct mass measurement provides the highest accuracy of hydrogen transferred, and the Micro MotionTm High Pressure Coriolis (HPC) Series Meter was designed with this application in mind. Flame and gas sensors like the RosemountTm 975HR Multi-Spectrum Infrared Hydrogen Flame Detector and Rosemount Incus Ultrasonic Gas Leak Detector provide early warnings to potential safety hazards.

Pipelines offer another alternative, either as a dedicated hydrogen pipeline or by blending hydrogen into the natural gas pipelines within regulatory limits. Extensive pipeline systems totalling over 4,600 kilometres already exist across North America and Europe with more networks in progress. These pipelines enable high volume offtakers to efficiently get the hydrogen they need.

Throughout the world, hydrogen is being injected into natural gas pipelines to create blended natural gas that can be combusted similarly to natural gas. At injection points, it is important to account for any existing hydrogen already blended into the natural gas before injecting any additional hydrogen to ensure compliance and end use performance.  A Rosemount 700XA Gas Chromatograph can analyze the pipeline upstream and downstream of the injection point to ensure accurate mixing ratios. Adjustments up and down can be controlled by measuring the flow rates of the natural gas line and the hydrogen line. Depending on accuracy needs and pipeline size, Micro Motion Coriolis Flow Meter, the Flexim FLUXUS G831 Gas Ultrasonic Flow Meter for Hazardous Areas, or Ultrasonic Gas Flow Meters can be used.

Hydrogen can also be converted to ammonia and moved using the existing ammonia value chain. This can simplify transportation overseas or long land distances as ammonia liquifies in conditions of -34˚ C at ambient pressure and 25˚ C at 10 bar pressure. The ammonia can then be converted back into hydrogen through ammonia cracking.

Metering takes place at various points throughout these transportation methods to verify volumes for billing and process control. Every time hydrogen changes ownership, a custody transfer system ensures accuracy.

At hydrogen transfer locations, accountability is essential. At those points, it is necessary to determine how much hydrogen has been moved for accounting purposes and accurate payments. Precise measurements at transfer points can also help detect the presence of leaks in the upstream process, indicated by an unexpected change in the hydrogen total.

Metrology-certified metering solutions from Emerson combine Micro Motion Coriolis Flow Meters and Rosemount Gas Chromatographs to provide assured accuracy and traceability.

For more information, check out our new eBook – Measurement Instrumentation for Improving Hydrogen Storage and Transport. Here you can also connect and interact with one of our experts to discuss any hydrogen related questions.

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