Applications Inert gas

1 applications

1.1 inert gas systems on ships
1.2 welding
1.3 diving

applications

because of non-reactive properties of inert gases useful prevent undesirable chemical reactions taking place. food packed in inert gas remove oxygen gas. prevents bacteria growing. chemical oxidation oxygen in air avoided. example rancidification of oil. in food packaging, inert gases used passive preservative, in contrast active preservatives sodium benzoate (an antimicrobial) or bht (an antioxidant).

historical documents may stored under inert gas avoid degradation. example, original document of u.s. constitution stored under humidified argon. helium used, less suitable because diffuses out of case more argon.

inert gases used in chemical industry. in chemical manufacturing plant, reactions routinely conducted under inert gas if not sensitive air, minimize fire hazards. in such plants , in oil refineries, transfer lines , vessels purged inert gas, avoid residual solvents or process fluids catching fire. @ bench scale, chemists perform experiments on air-sensitive compounds using air-free techniques developed handle them under inert gas.

inert gas systems on ships

inert gas produced on board crude oil carriers (above 8,000 tonnes)(from jan 1, 2016) using either flue gas system or burning kerosene in dedicated inert gas generator. inert gas system used prevent atmosphere in cargo tanks or bunkers coming explosive range. ig keeps oxygen content of tank atmosphere below 5% (on crude carriers, less product carriers , gas tankers), making air/hydrocarbon gas mixture in tank rich (too high fuel oxygen ratio) ignite. ig important during discharging , during ballast voyage when more hydrocarbon vapour present in tank atmosphere. inert gas can used purge tank of volatile atmosphere in preparation gas freeing - replacing atmosphere breathable air - or vice versa.

the flue gas system uses boiler exhaust source, important fuel/air ratio in boiler burners regulated ensure high quality inert gas produced. air result in oxygen content exceeding 5%, fuel oil result in carryover of dangerous hydrocarbon gas. flue gas cleaned , cooled scrubber tower. various safety devices prevent overpressure, return of hydrocarbon gas engine room, or supply of ig high oxygen content.

gas tankers , product carriers cannot rely on flue gas systems (because require ig o2 content of 1% or less) , use inert gas generators instead. inert gas generator consists of combustion chamber , scrubber unit supplied fans , refrigeration unit cools gas. drier in series system removes moisture gas before supplied deck. cargo tanks on gas carriers not inerted, hold space around them is. arrangement allows tanks kept cool using small heel of cargo while vessel in ballast while retaining explosion protection provided inert gas.

welding

in gas tungsten arc welding (gtaw), inert gases used shield tungsten contamination. shields fluid metal (created arc) reactive gases in air can cause porosity in solidified weld puddle. inert gases used in gas metal arc welding (gmaw) welding non-ferrous metals. gases not considered inert behave inert gases in circumstances encountered in use can used substitute inert gas. useful when appropriate pseudo-inert gas can found inexpensive , common. example, carbon dioxide used in gas mixtures gmaw because not reactive weld pool created arc welding. reactive arc. more carbon dioxide added inert gas, such argon, increase penetration. amount of carbon dioxide determined kind of transfer using in gmaw. common spray arc transfer, , commonly used gas mixture spray arc transfer 90% argon , 10% carbon dioxide. (listed many different names depending on gas supplier).

diving

in underwater diving inert gas component of breathing mixture not metabolically active, , serves dilute gas mixture. inert gas may have effects on diver, these thought physical effects, such tissue damage caused bubbles in decompression sickness. common inert gas used in breathing gas commercial diving helium.