How a Unique Coriolis mass flow meter design can boost hydrogen refuelling operations?
Hydrogen has been identified as a promising alternative fuel for the future to replace conventional petroleum fuels in multiple sectors including vehicle fuelling. However, due to it physical properties, Hydrogen requires special considerations when it comes to distribution, storage, measurement, and safety of operation. For example, when measuring the quantity of hydrogen transferred from a dispenser to a vehicle, it is important to ensure measurement accuracy for consumer protection and satisfaction. Also, it is important to carry efficient and safe transfer at high operating pressure.
Principle of Operation: Coriolis Mass Flow Meter
The basic operation principle of a Coriolis mass flow meter depends on the change in frequency, phase shift, and amplitude of the parallel flow tubes when fluid is traveling through them (see Figure 1). This shift is translated into direct measurement of mass flow and density which is one of the primary advantages of a Coriolis Mass flow meter. Another primary advantage of the Coriolis flow meter is that its performance is independent from the fluid profile conditions allowing a degree of freedom in installation and mounting without any minimum required upstream piping configurations.
Figure 1: Operating principle of a Coriolis Mass flow meter.
Coriolis mass flow meters are widely used in a variety of industrial applications such as Oil and Gas, Chemicals, Life Sciences, Food and Beverage, Minerals and Mining, etc..
The accuracy performance of a MicroMotion Elite Coriolis mass flow meter is specified at ±0.1% (0.05% for premium option) of rate in liquid measuring applications and ±0.25% of rate in gas measuring applications. In gaseous refueling applications, the accuracy requirement is specified in terms of the complete batch. Therefore, a typical accuracy performance for a High-Pressure Coriolis in gaseous refueling is specified at ±0.5% of batch.
A Unique High-Pressure Coriolis Mass Flow Meter for Hydrogen Fuelling
For hydrogen refuelling, the Coriolis Mass flow meters must be designed to accommodate the complex fuelling protocol needed to ensure safe and accurate transfer of Hydrogen. Specifically, the Coriolis flow meters must be capable to operate under extremely high pressures, varying flow rates and low temperatures.
For the RHeaDHy project, Emerson is developing and constructing a High-Pressure Coriolis Mass flow meter to meet the below fuelling specifications intended for the RHeaDHy project:
- Measure hydrogen flow up to 18 kg/min
- Operate at design pressure of 950 bar
- Operate at a temperature range between -46 to 200°C
- Lowest possible pressure drop at the highest flow rate
In order to achieve the above specification, Emerson’s primary focus is to design the manifold and flow tubes such that the new flow meter construction is capable to achieve the desired measurement accuracy. That would translate into:
- Expanding the size of the flow meter in comparison to the existing model to accommodate the requirement for twice the flow rate at a significantly lower pressure drop requirement.
- Selection of high-strength flow tube material that is insensitive to Hydrogen embrittlement and machined to comply with relevant codes and standards such as ASME B31.3 CH IX
The outcome is a compact and durable design, see Figure 2, suitable for installation within the dispenser, if desired.
Figure 2: Unique High-Pressure Coriolis Mass Flow Meter for Hydrogen Fuelling.
The new High-Pressure Coriolis Mass flow meter is expected to have potential applications not only in hydrogen refuelling, but also in chemical injection, where high-pressure measurement is needed. The device could offer a competitive edge in the market, as it can accommodate higher flow rates proportionally lower pressure drop than what is available now in the market.
Authors: Yaser Alghanmi and Maarten Brugman (Technologies et Solutions d’automatisation), and Jean HERISSON (Benkei)