Inertgas

Inert gases are called gases very unreactive ( inert) are, so to participate in only a few chemical reactions. If they are molecular compounds, as they are characterized in general by a strongly negative standard enthalpy of. Whether a particular gas is known for a particular application as the inert gas, however, is dependent on the specific case. The inert gases include, for example, nitrogen and any inert gases (helium, neon, argon, krypton, xenon, radon).

Inert gases are used in order to keep the air or other gases by certain chemical reactions. In general, inert gases are used to reduce or replace all, so that an explosion or the propagation of a combustion prevents the oxygen content.

Explosion protection

Shipping

In tankers when pumping out ( delete) the combustible liquid cargo is poured to fill the remaining volume in the tank resulting inert gas to prevent an explosive air-gas mixture is produced, which could be ignited by sparks. For this, the inert gases of the main propulsion plant are used (diesel engine exhaust gases at engine boat or boiler exhaust gases at the turbine ship) in the oil tanker shipping.

On LPG tankers special inert gas systems are installed because the qualitative requirements of the inert gas are higher than in the oil tanker shipping. In a combustion of low-sulfur diesel fuel is combusted, that the residual oxygen content in the exhaust gas by volume 0.2 - % is not exceeded. Soot particles and water-soluble substances are then washed by sea water. Thereafter, the gas is cooled using a refrigeration system ( refrigeration dryer ) to 8 to 10 ° C, thereby the water contained in the gas condenses and is removed via a separator. The so pre-dried gas is then withdrawn through a desiccant dryer, the residual moisture content in order to ensure the required dew point depending on the charge, a dew point ≤ -40 ° C has to be ensured in the LNG away. For inerting of the barriers in the LNG shipping nitrogen is used. This is either supplied in liquid form by tanker on board and evaporated as required or obtained by means of membrane systems on board from the air.

Combat aircraft

Similarly as in shipping the fuel tanks of fighter aircraft are pressurized with an inert gas to prevent fire and explosion. The project uses dry nitrogen.

After a Boeing 747 crash in 1996, which was caused by explosion of a fuel tank by sparking the tank electrics, it was discussed this practice in civil aviation. In addition to looking for ways to influence the kerosene so that it is non-flammable or at least flame retardant, under the prevailing conditions in the tank.

Chemical Industry

Inert gases are used in the chemical industry acted in storage tanks for explosion protection, and they are also used as a protective gas for production assurance.

Other technical applications

• Fire protection: Fire fighting in inert gas extinguishing systems or for preventive fire protection by inerting in active fire prevention systems
• Chemical synthesis when reaction components would (eg metallic lithium ) react undesirably with components of air ( inert gas or Schlenk technique )
• Packaging technology to extend the shelf life of foods
• Welding, where argon is used as inert gas
• Reflow soldering, where nitrogen is used
• In gas systems, eg for leak testing
• Work in the so-called glove box
• In incandescent lamps, to prevent burning out the filament
• Gas chromatography, there use as a mobile phase ( carrier gas)
• Anesthesia, there nitrous oxide has long been regarded as inert gas and for this reason not included in the toxicological assessment of anesthetic gas exposure of the anesthesia staff
• Diving, there helium is used in breathing gas mixtures as a remedy for nitrogen narcosis
• As propulsion methods for space in spacecraft or space stations, mostly for control nozzles and only power source