Metal Hydride Hydrogen Compression

ZnoNova Materials

A metal hydride compressor does something mechanical compressors cannot: it raises hydrogen pressure with heat rather than with a piston. Absorb at low pressure and low temperature, heat the bed, and the hydrogen comes off at a higher pressure. There are no seals on a moving shaft, so there is no route for lubricant to reach the gas and no wear surface to maintain.

Why anyone would trade a compressor for a heat source

PurityNo dynamic seals, so no lubricant contamination path. This matters most where the hydrogen feeds a fuel cell or an analytical process.

Silence and vibrationNo rotating mass. Relevant indoors, in labs and in occupied buildings.

MaintenanceNo wear parts in the gas path. The failure modes move to the thermal system instead.

Waste heat as the inputIf the heat is already there, the compression energy is largely already paid for.

The honest counterweights

Throughput is low relative to a mechanical compressor of similar cost. A hydride stage is a batch process bounded by how fast you can move heat in and out of a bed. If your duty is continuous high flow, a mechanical compressor is the right answer and we will say so.
You need the heat, at grade. A magnesium system wants roughly 375 °C for desorption. Lower-temperature hydride families exist and are a different material class from ours.
Compression ratio per stage is limited by the plateau pressures of the alloy at your two temperatures. Multi-stage designs exist; the design work is real.
We supply the catalyst, not the compressor. Bed design, heat exchange and controls are your side or a joint development.

What the catalyst changes

Cycle time is the whole economics of a hydride compressor, and cycle time is kinetics. In the peer-reviewed work on our Pd/MWCNT catalyst: 446 s absorption and 735 s desorption at 375 °C, with desorption activation energy reduced from 132.7 to 98.5 kJ/mol. Faster kinetics means more cycles per day from the same bed, which is the lever that decides whether the concept is viable at your throughput. Citations and DOIs are here.

Where it fits best

Laboratory and analytical hydrogen supply, fuel-cell test benches, small-scale refuelling where purity dominates, and any site with a continuous 300–400 °C heat rejection stream. It fits worst where you need high continuous mass flow and have no process heat.

Questions buyers ask

How high a pressure can a hydride stage reach?

That is set by the alloy's plateau pressure at your hot temperature, not by the catalyst. The catalyst changes how fast you get there, not the pressure ceiling. Tell us your inlet and target pressures and the design conversation starts from the alloy.

Is it more efficient than a mechanical compressor?

Not on electricity alone. It becomes attractive when the heat is waste heat you already have, or when purity and silence are worth more than efficiency.

What maintenance does it need?

No wear parts in the gas path, but the thermal system, valves and the bed's cycling stability become the things you maintain. Cycling degradation of the bed is a real design consideration.

Do you supply the compressor?

No. We supply the Pd/MWCNT catalyst for the magnesium bed. Bed and system design is yours or a joint development.

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