D1E.1 Impact of high speed hydrogen flow on system integrity and noise

The Netherlands has an extensive pipeline infrastructure for the transport and storage of natural gas. This existing infrastructure could be used in the future for hydrogen transport. For reasons of personal and environmental safety and to ensure reliable supply, the infrastructure is built and operated according to standards and norms for pipeline integrity. Currently, the reliability is ensured by complying with design codes and standards and by using systematic approaches for maintenance and trouble-shooting. The question arises whether the same amount of energy transported with hydrogen as currently with natural gas results in a larger impact on the integrity of the system and the environment around it.

High flow velocities are associated to larger pressure drop and higher risk of noise emissions, vibrations and erosion. The flow speed is determined by the selection of system capacity, operating conditions, hardware sizing and economic evaluation. The combination that provides the lowest levelized cost of transport determines what the resulting flow velocity is at all points of the transport system. However, the flow velocity itself can be a constraint in this optimization due to the risks mentioned. For natural gas, this limit is commonly set at 20 m/s (72 km/h), though this is not the case for every segment of the network and at specific locations this can reach higher values. If the same limit would be applied to hydrogen, it may be an unnecessarily conservative constraint on the capacity of new and re-used systems to transport energy.

In this study, a review is made of flow-induced risk mechanisms for intrusive equipment, flow-induced turbulence, flow-induced pulsations, acoustics-induced vibration, flow-induced noise and erosion. Capacity from a pressure drop perspective is also checked. This is done scoping the Dutch high-pressure gas transport system (GTS), through the RNB systems, up to the gas receiving spot for the end user. A generic benchmark between natural (G-) gas and hydrogen is presented, when an equal energy transport capacity between the two carriers is assumed, which in practice means whether hydrogen can flow 3 times faster than natural gas. The objective of the benchmark is to evaluate whether under this assumption, any of the phenomena analysed hinders transport at such conditions. In other words, whether the allowable flow velocity for hydrogen can be larger than the value traditionally used for natural gas.