Inert gases hazards

Storage tanks should be designed in accordance with the ASME code for unfited pressure vessels. AH-welded constmction is recommended. Ethylene oxide storage tanks should be electrically grounded, isolated from potential fire hazards, and equipped with pressure rehef devices. New equipment should be cleaned of iron oxide and immediately purged with inert gas. 

For example, in rotary vacuum dryers it is possible to prevent the formation of explosible dust-air mixtures by setting and monitoring a certain partial vacuum (negative pressure). This pressure value must be determined by experiment for each type of dust. With pressures of less than O.I bar, in general, hazardous effects of dust explosions need not be anticipated. If the vacuum system malfunctions, the partial vacuum must be released by inert gas and the instaUation shut down. 

Fire or explosion hazards require special motor enclosures. Hazards include combustible gases and vapors such as gasoline dust such as coal, flour, or metals that can explode when suspended in air and fibers such as textile lint. The land of motor enclosure used depends on the type of hazard, the type and size of motor, and the probability of a hazardous condition occurring. Some available enclosures are explosionproof motors, which can withstand an internal explosion force-ventilated motors cooled with air from a safe location and totallv enclosed motors cooled bv air-to-water heat exchangers and pressurized with safe air, instrument air, or inert gas,... 

When using inert gas, provide protection against personnel asphyxiation hazards... 

For filter boxes, provide remote and automatic filter box lid closing on trip of appropriate fire detection device. Fire detection device may also be interlocked to stop solvent feed, trip deluge internal to filter box and/or trip inert gas blanket for filter box (caution, be aware inert gas is a potential asphyxiation hazard)... 

Inert gas-filled motors can also be used in refineries and chemical plants, but their applications are limited. They have tightly fitted covers and oil seals around the shaft to minimize gas leakage, are continually pressurized with an inert gas or instrument air, and are equipped with an internal air-to-water heat exchanger. Inert gas-filled motors are suitable for any hazardous location but require auxiliaries such as cooling water, gas pressurizing system, and control accessories. 

Immediately after the running test, any compressor intended for toxic, hazardous, flammable, or hydrogen-rich service should be gas tested with an inert gas to the maximum seal design pressure. The test is held at least 30 minutes and the casing and its joints checked for leaks, using a soap bubble method or other suitable means for leak detection. When no leaks are detected, the compressor will be considered acceptable. 

Skin proteetion may neeessitate use of full proteetive suits. When eatalysts are dumped from reaetors at the end of a proeess they may prove to be extremely dusty as a result of reduetion in partiele size during the reaetion proeess. Again, depending upon the nature of the hazard, ventilation, personal proteetion, and use of temporary enelosures to prevent contamination of the general work area should be considered. Some catalysts are pyrophoric and some catalyst beds are inerted with the added possibility of fire, or release of inerting gas into the workplace which may cause asphyxiation. 

Carbon dioxide systems-Tliis system can be used where there is a handling and storage of gaseous and flammable materials, electrical equipment, and hazardous solids by introducing an inert gas (such as carbon dioxide) into the area in order to reduce the concentration of oxygen to the point where the fire will be extinguished. 

Hazards attendant on use of ethylene oxide in steriliser chambers arise from difficulties in its subsequent removal by evacuation procedures, owing to its ready absorption or adsorption by the treated material. Even after 2 evacuation cycles the oxide may still be present. Safety is ensured by using the oxide diluted with up to 90% of Freon or carbon dioxide. If high concentrations of oxide are used, an inert gas purge between cycles is essential [7], The main factors in safe handling... 

Finely powdered pyrites, especially in presence of moisture, will rapidly heat spontaneously and ignite, particularly in contact with combustible materials [1]. Inert gas blanketing will prevent this [2], Precautions to reduce the self-ignition hazards of powdered pyrites, and the explosion hazards of pyrites-air mixtures in the furnaces of sulfuric acid plants have been detailed and discussed [3], Further studies on minimum moisture content of Portuguese pyrites for safe transportation and storage are reported [4],... 

Reaction to give tetrafluorooxathietane 2,2-dioxide (tetrafluoroethane sultone) had been used industrially and uneventfully, but reaction with excess sulfur trioxide may cause explosive decomposition to carbonyl fluoride and sulfur dioxide [1]. An incident involving the same explosion hazard was reported 11 years later [2], Use of inert gas to prevent explosion has been patented [3],... 

Since potassium will burn in air, it is important to cut, slice, or powder the metal under an inert hydrocarbon solvent such as kerosene, toluene, or xylene. The air in the reaction flask should be displaced by an inert gas such as nitrogen. In this manner, fire hazard in handling potassium metal will be minimized. 

Although microwave-heated organic reactions can be smoothly conducted in open vessels, it is often of interest to work with closed systems, especially if superheating and high-pressure conditions are desired. When working under pressure it is strongly recommended to use reactors equipped with efficient temperature feedback coupled to the power control and/or to use pressure-relief devices in the reaction vessels to avoid vessel rupture. Another potential hazard is the formation of electric arcs in the cavity [2], Closed vessels can be sealed under an inert gas atmosphere to reduce the risk of explosions. 

Chemical Incompatibility Hazards While N2 and C02 may act as inerts with respect to many combustion reactions, they are far from being chemically inert. Only the noble gases (eg., Ar and He) can, for practical purposes, be regarded as true inerts. Frank (Frank, Inerting for Explosion Prevention, Proceedings of the 38th Annual Loss Prevention Symposium, AIChE, 2004) lists a number of incompatibilities for N2, C02, and CO (which can be present in gas streams from combustion-based inert gas generators). Notable incompatibilities for N2 are lithium metal and titanium metal (which is reported to burn in N2). C02 is incompatible with many metals (eg., aluminum and the alkali metals), bases, and amines, and it forms carbonic acid in water,... 

The low molecular weight alkanes such as methane and butane can be pumped with the gas ballast valve closed or using Inert gas as the gas ballast and/or at inaeased temperature of the pump. But important -Increased explosion hazard ... 

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