Why is xenon an inert gas

Inert gas

As Inert gases are gases that are very inert (inert), i.e. only take part in a few chemical reactions. If they are molecular compounds, they are usually characterized by a strongly negative standard enthalpy of formation. Whether you want to use a specific gas for a specific application as a Inert gas referred to, but still depends on the specific case. The inert gases include, for example, nitrogen and all noble gases (helium, neon, argon, krypton, xenon, radon). Inert gases are used to keep other gases, such as air, away from certain chemical reactions. As a rule, inert gases are used to reduce or completely replace the oxygen content and to absorb the heat of reaction so that combustion cannot continue.

Technical applications for inert gases

  • In the chemical industry, inert gases are used as protective gas in storage tanks for explosion protection; they are also used to safeguard production.
  • Shipping (explosion protection): In tankers, when the flammable liquid cargo is pumped out (extinguished), inert gas is filled in to fill up the remaining volume in the tank, in order to prevent an explosive air / gas mixture from developing, which could be ignited by sparks. For this purpose, the inert exhaust gases from the main propulsion system (diesel engine exhaust from the motor ship or boiler exhaust from the turbine ship) are used in the oil tanker voyage. Special inert gas systems are installed on liquid gas tankers, as the qualitative requirements for the inert gas are higher than in the oil tanker voyage. Low-sulfur diesel oil is burned in a combustion chamber in such a way that the residual oxygen content in the exhaust gas does not exceed 0.2% by volume. Soot particles and water-soluble substances are then washed out using seawater. The gas is then cooled to 8 to 10 ° C with the aid of a refrigeration system (refrigeration dryer), during which the water contained in the gas condenses and is removed via a separator. The residual moisture is then removed from the pre-dried gas in an adsorption dryer in order to ensure the dew point required depending on the load. A dew point ≤ −40 ° C must be ensured during the LNG journey. In liquid gas shipping, nitrogen is used to render the barriers inert. This is either delivered on board in liquid form by tanker and evaporated there as required, or obtained from the air by means of membrane systems on board.
  • Combat aircraft (fire and explosion protection): Similar to the shipping industry, the fuel tanks are also charged with an inert gas to prevent fire and explosion. Dry nitrogen is used. After a Boeing 747 crash in 1996, which was caused by the explosion of a fuel tank due to sparking of the tank electrics, it was discussed whether this could also be practiced in civil aviation. In addition, one is looking for ways to influence the kerosene in such a way that it is incombustible or at least hardly inflammable under the conditions prevailing in the tank.
  • Fire protection: Use of inert gases for fire fighting in inert gas extinguishing systems or for preventive fire protection by inerting in active fire prevention systems
  • Welding, where argon is used as a protective gas
  • Diving, where helium is used in breathing gas mixtures as a remedy for nitrogen anesthesia
  • Gas chromatography, where it is used as a mobile phase (carrier gas)
  • Inert gas systems, a typical example of this is the so-called glove box (glove box)
  • Chemical synthesis if reaction components would react unintentionally with oxygen, moisture, carbon dioxide or nitrogen (e.g. metallic lithium) (inert gas or Schlenk technology)
  • Anesthesia, where laughing gas was considered an inert gas for a long time and for this reason was not included in the toxicological assessment of anesthetic gas exposure by anesthetists
  • Packaging technology to extend the shelf life and preserve the aroma of food
  • In incandescent lamps to prevent the filament from burning up (normal ambient atmosphere would let the filament glow through immediately)
  • As propulsion methods for space travel in space probes or space stations, mostly for control nozzles as the sole propulsion source
  • TRGI: e.g. B. for leak testing of gas systems.

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