Valves and flow equipment for hydrogen applications

Hydrogen systems require valves and flow equipment with suitable tightness, material compatibility and operating capability for the pressure and temperature range of the installation. Due to its small molecular size, hydrogen can have an increased tendency to escape through connections, gaskets, packing and stem sealing points.

Hydrogen production, compression, storage, distribution and utilisation units require flow control in main and auxiliary lines. Valve selection is based on operating pressure, temperature, gas purity, operating frequency, flow direction, isolation requirements and connection to the automation or safety system.

Typical applications

• Gaseous hydrogen lines in production, compression, storage and distribution.
• Auxiliary circuits in electrolysis units and gas purification systems.
• Hydrogen supply lines to burners, reactors and fuel cells.
• Venting, relief, purge and safe isolation systems for network sections.
• Nitrogen or inert gas networks for line purging and inerting.
• Auxiliary cooling water, compressed air and control instrument networks.
• Measurement, pressure regulation and equipment protection stations.

Equipment selection criteria

• Operating pressure, design pressure and valve differential pressure.
• Temperature range during normal operation, start-up, shutdown and relief conditions.
• Compatibility of body, seat, stem, gasket and packing materials with hydrogen.
• Required seat and stem tightness class.
• Risk of permeation, external leakage and emissions from sealing points.
• Isolation, control, non-return, relief or overpressure protection function.
• Connection type: flanged, welded, threaded or special tubing connection.
• Automation, fail position and control system signal requirements.

Indicative equipment

• Isolation valves for hydrogen and auxiliary gas lines.
• Control valves for pressure, flow or mixing ratio regulation.
• Pressure reducing valves and pressure regulators for feed pressure stabilisation.
• Check valves for backflow prevention in compressors and networks.
• Safety and relief valves for protection of pipework, vessels and individual sections.
• Bellows-sealed valves or special stem sealing arrangements where reduced external leakage is required.
• Line strainers for protection of regulators, instruments, control valves and nozzles.
• Pneumatic and electric actuators for operation from automation or safety systems.

For each application, the design pressure and temperature, gas composition and purity, sealing requirements, installation point, operating method and safety logic of the system should be reviewed. These data define the valve type, nominal size, pressure class, construction materials, sealing arrangement and suitable actuator.