Have you ever heard of the compressibility factor?
If the answer is no, maybe that’s the answer to why your hydrogen storage calculations are not working out. Here’s what it is and why it should be used.
The compressibility factor is a value, Z, that tells us how far away we are from the ideal conditions of a gas. In other words, it is a value that we must add to the ideal gas equation to go from ideal to real. This factor varies with pressure and temperature (as can be seen in the figure). Therefore, when calculating storage systems (among many other things), it is necessary to take it into account, since the higher the pressure, the less hydrogen behaves as an ideal gas.
The kinetic theory of gases shows that a gas behaves as an ideal gas, first if the gas molecules are hard, round, infinitesimally small spheres occupying a negligible volume and, second, if there are no forces between these molecules, except during collisions. This is true for most gases at low pressure and temperatures well above the critical temperature. This is the highest possible temperature at which a substance can condense.
The formula is, as for ideal gases, but modified: PV = ZnRT
If you have any questions, Lean Hydrogen can help you to boost your hydrogen project. We are an engineering and consulting firm specialized in renewable hydrogen. Our team has been in the sector for more than a decade and since 2020, Lean Hydrogen has developed numerous projects including:
- MW-scale electrolysis hydrogen production plants.
- Hydrogen injection systems in Natural Gas networks.
- Hydrogen refueling stations.
- Energy storage.
- Decarbonization of industry by replacing Natural Gas with renewable hydrogen.
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Source and Image: Handbook of Hydrogen Storage: New Materials for Future Energy Storage. Edited by: Michael Hirscher. WILEY-VCH
