Many fuelling stations store hydrogen in a gaseous state or produce gaseous hydrogen on site. So Linde engineers custom-developed a new compression technology to support gaseous fuelling.
In our ionic compressor, conventional metal pistons are replaced by a specially designed, nearly incompressible ionic liquid. These organic salts remain liquid within a specified temperature range. Because they do not have a vapour pressure, they do not evaporate or mix with the hydrogen. The special physical and chemical properties of these liquids mean they can be adjusted to meet almost any requirements.
Highlights of Ionic Liquids
- No contamination of hydrogen (or other gases)
- Not volatile and not combustible
- Environmentally safe
- Good thermal capacity
- Good lubricating qualities
- Corrosion inhibition
- Elimination of seals and bearings in the compressor as ionic liquids do not mix with hydrogen gas.
The gas is compressed in the cylinder by the up-and-down motion of the liquid column, similar to the reciprocating motion of an ordinary piston. Because the hydrogen is compressed at an almost isothermal temperature, ionic compressors are considerably more efficient than conventional compressors. The compressor can also be used with liquid hydrogen. The liquid is simply vaporised and then compressed.