Pressurized gas
According to the Federal Worksheet, all substances and sometimes mixtures of substances are referred to as compressed gas ,
- whose critical temperature T c is below 50 ° C or
- whose saturation vapor pressure at 50 ° C is above 300 kPa or
- whose vapor pressure at 15 ° C is over 200 kPa.
safety instructions
Many compressed gases are dangerous because of their reactivity. Be differentiated
- Flammable gases: A mixture of the compressed gas with air can be ignited (e.g. methane )
- Self-igniting gases: Similar to flammability, but the ignition temperature is below 100 ° C
- Chemically unstable gases:
- Exothermic decomposition occurs when heated
- A chemical reaction occurs through catalytically active substances (e.g. through unsuitable containers alone)
- Toxic gases
- Corrosive gases (e.g. sulfur dioxide )
This classification is particularly important for the type of pressurized gas container used ( gas cylinders , gas cartridges ).
use
Energy source
The work involved in compression can be used to relax the gas.
- Pressurized gas delivery was used in liquid propellant rockets prior to the availability of delivery turbines
- Pneumatics (especially also for compressed air )
- Propellant
Inhibitors
- Compressed inert gases (especially argon, nitrogen and carbon dioxide) are used as protective gases in chemical reactions that have to take place in the absence of oxygen
- Compressed carbon dioxide is used as a fire extinguisher
Transport and storage
- Many non-liquefiable gases (supercritical substances, e.g. hydrogen , nitrogen , oxygen , methane , helium, etc.) are only transported and stored in compressed form in order to reduce the space requirement; see pressurized gas container
- Fuels for natural gas and hydrogen powered vehicles