When producing hydrogen through steam methane reforming or electrolysis, controlling the process and pipeline pressure is a critical measurement. When considering pressure transmitters for hydrogen applications, here are some key criteria to consider:
- What gases or liquids will the transmitters be in contact with?
a. Hydrogen – a gold plated or ceramic membrane may be necessary (hydrogen may permeate other materials)
b. Oxygen – degreasing/cleaning may be necessary as oxygen may react to oils and grease - Accuracy – consider not just “reference accuracy” – which often refers to testing not in an industrial setting but a tightly controlled laboratory in conditions that generally do not resemble a plant environment. Look at factors that affect total performance and accuracy of the transmitter including: long-term stability, response time, and temperature effect.
- Long-term maintenance – with a new buildout or application to support a hydrogen hub project, several new transmitters will be required. At the time of installation, consider how often you wish to go back and maintain the transmitters for calibration (may be intrusive and require the instrument be out of service) or verification options such as Heartbeat, which is less disruptive and may help contribute to lower life cycle maintenance costs.
- Method of protection/hazardous area certification. In the USA, this often ensures transmitters comply with either explosion-proof ratings (i.e., CSA C/US XP Cl.I Div.1) or intrinsically safe ratings.
- Setup and configuration methods – consider allowing factory startup and commissioning services or if plant personnel or contractors will be setting up, the methods vary but assuming a 4-20 mA/HART protocol: a. Transmitter Bluetooth connections allow the technician to be in a safe remote area b. Using pushbuttons on the transmitter – labor-intensive, but convenient and no additional tools c. HART Handheld such as a Meriam 5150 Series HART Communicator – often connected directly at the instrument or control panel d. Laptop PC with a HART Modem and software such as DeviceCare/FieldCare
For an example of hydrogen pressure transmitter material selection (i.e. gold or ceramic diaphragms), please see: https://app.box.com/s/s5rfn81elf5caujkygsr7qf3bf88qjab
For an example of Bluetooth configuration, please see: https://www.youtube.com/watch?v=YiLm7-9sg1I