Running it day to day: what to watch in normal operation, level and water make-up, the operating range, what changes at low current, and the normal shutdown sequence.
The HXS-30 has completed first operation and is under long-term evaluation. Check any operating condition not covered in this chapter with us first.
- Rated point360 A · 0.1 M KOH · 50 °C
- Temperature limit80 °C
- Make-upYours, by your BoP procedure
First timeRead the four sections in order. The first is what you watch every day; the second is what people most often miss.
Done this beforeThe limits table and the shutdown sequence are enough.
On this pageWhat to watch in normal operation
What to watch in normal operation
Keep the circulation steady and watch four things.
- Flow and temperature
- Confirm the flow is stable and the temperature is near target (50 °C recommended). If it keeps rising despite available cooling, reduce the current or stop.
- Voltage
- Monitor the stack voltage continuously, and the spread between cells if you measure individual cell voltages. A sudden jump or fluctuation at constant current means reduce the current or stop.
- Leaks
- Check around the ports, the external fittings and the cell edges periodically. Wetness or white crystals mean stop, correct the cause, then resume.
- The wet outlet return
- Confirm the return from the oxygen and electrolyte outlet to the tank flows smoothly. Gas trapping or a broken return means inspect the routing and the backpressure and correct it before continuing.
Level and water make-up
Electrolysis consumes water; KOH is not consumed. The tank level therefore falls, and make-up depends on your procedure. Water consumption at rated current is in the specification table on the product page.
- Keep the level high enough for stable circulation and cooling.
- Add DI water to the tank by your external BoP procedure.
- At the 30 kW scale the level falls quickly. If make-up is manual, keep the interval short or fit automatic make-up.
- If the level gets too low or the circulation becomes unstable, stop and correct it before continuing.
Limits and recommended values
| Parameter | Recommended · rated | Limit and notes |
|---|---|---|
| Current | 360 A rated | Ask us before running above rated |
| Stack voltage | 80 V rated | Rises during operation; supply up to about 92 V |
| Electrolyte | 0.1 M KOH | Ask us about other concentrations |
| Electrolyte temperature | 50 °C | 80 °C maximum |
| Electrolyte flow | Agreed for your system | Datasheet measurements at 36 L/min |
| Hydrogen pressure | Atmospheric | 10 barg maximum |
| Anode pressure | Atmospheric | Not pressurised |
Low-current and part-load operation
Running below rated current changes two things: the electrolyte heats less, and the hydrogen-in-oxygen ratio rises.
| What | Why | What to do |
|---|---|---|
| Electrolyte temperature | Less heat is generated, so it does not reach the recommended temperature | Fit a tank heater, temperature monitoring and over-temperature protection in the external BoP |
| Hydrogen in oxygen | Hydrogen crossing the membrane barely depends on current, while oxygen output is proportional to it. At lower load the same hydrogen mixes into less oxygen | Measure hydrogen in oxygen and interlock at 2 vol%. If you plan long periods at low load, tell us in advance |
Normal shutdown
- Reduce the current step-wise to 0 A.
- Turn off the DC output.
- Keep circulation running as long as needed to cool down.
- Stop circulation once it has cooled.
- Turn off the tank heater if you used one, and secure the system by your site procedure.
- Do a visual leak check around the ports and fittings.
What this chapter is based on
- HXS-30 datasheetPDF · 502 KB
- HXS-30 exterior STEP modelOn request
Ask the engineer who built it
If your case is not covered here, send us the operating condition and what you observed. The engineer who designed the system answers directly.