D1B.1 Operation of gas stations with spring loaded regulators with hydrogen

The Dutch system operators (DSOs) are planning to examine if the existing – or slightly modified – gas pressure reducing and metering stations that are currently being applied for use with natural gas, will also be suitable for use with hydrogen (H₂).

At the moment, only limited knowledge is available about applying the current gas pressure reducing and metering stations for natural gas are suitable to operate with hydrogen to adequately, reliably and safely reduce pressure.

The goal of this research program focuses on the following key question: is an existing gas pressure reducing and metering station, operated with natural gas and equipped with a spring loaded safety valve, also suitable for hydrogen.

For the execution of the experimental program, a gas pressure reducing and metering station has been made available by Enexis on behalf of the DSOs. The design capacity of the station is 100 m³_n/h (natural gas) (according to gAvilar specifications) with a minimum inlet pressure of 3 bar. The gas pressure reducing and metering station is in compliance with the NEN 1059: 2019.

Also, a high pressure delivery station (HAS) has been made available by RENDO on behalf of the DSOs. The design capacity of this station is about 30 m³_n/h (natural gas) at 4 bar inlet pressure. This HAS is also in compliance with the NEN 1059: 2019.

The experimental program has been executed according to a test protocol which describes the different steps to be followed, the operational conditions and the circumstances of the specific measurements. The capacity of the safety valves exceed the capacity of the gas pressure reducing and metering station.

The gas pressure reducing and metering station was first tested with natural gas to a maximum flow of 200 m³_n/h. The station was then tested with hydrogen to a maximum flow of 600 m³_n/h. Other tests focusing on leak tightness and closing pressure were also executed according to the test protocol.

The high pressure delivery station (HAS) was first tested with natural gas to a maximum flow of 30 m³_n/h. The test was then repeated with hydrogen to a maximum flow of 90m³_n/h. Additional tests have also been executed here in accordance with the test protocol.

Conclusion

Based on the experiments, the main conclusion of this report can be formulated as follows:

The gas pressure reducing and metering station, equipped with spring loaded safety valves and designed for natural gas, can be used to adequately, reliably and safely reduce the pressure for hydrogen. The tests with the different safety valves show only small differences between natural gas and hydrogen when comparing the results for the steps from the test protocol.

Comments:

• The conclusion of this research involves the technical functionality of a gas pressure reducing and metering station. The long-term effects on the components have not been tested in this test program and as such, no conclusions can be drawn on this specific matter.