Gases, inert storage

Provision must be made for dry gas inerting of all storage and hold tanks. Nitrogen with a moisture content of less than 5 ppm is suitable. Tank pressures from 0 to 30 pslg are used, depending upon the foam density to be produced. 

In dry storage, spent fuel is surrounded by a gas enviromnent such as air or an inert gas. Dry storage facilities iiKlude the storage of spent fuel in casks, silos or vaults. 

Maturation is conducted in closed, full containers to prevent oxidation and aerobic growth of microorganisms. Etee air contact with low alcohol wine soon leads to vinegar. Except for those sherry types already mentioned, wines ate exposed to air minimally and temporarily. During transfers incident to bulk storage and processing, some air exposure is almost inevitable, mote in total the longer the wine is held. In the cases of white and pink table wines, it is ordinarily as neat zero as possible, and stainless steel or other impermeable containers, inert gas headspace, etc ate employed. Red wines withstand and even benefit from small but repeated exposures to air. 

Materials of Construction. In choosing the proper materials of constmction for storing and using hydrazine, it is necessary to consider both the effects of the material on the stabiUty and quaUty of the hydrazine as well as the effect of the hydrazine on the material of constmction. Hydrazine is thermally stable, storable for years without adverse effects either to the product or the storage container provided the recommended materials are used, all systems are clean, and an inert gas, ie, nitrogen, is maintained over the system at all times. Table 10 is a brief listing of materials compatibiUty (125). 

Storage of Flammable Materials. The preferred storage for flammable Hquids or gases is in properly designed tanks. Floating roof tanks frequently are used in the petroleum industry for flammable cmdes and products (see Tanks and pressure vessels). The vents on cone roof tanks should either be equipped with flame arrestors or the vapor space above the contents should be inerted with a nonflammable gas or vapor, unless the flash point is weU above the maximum ambient temperature, the contents are not heated above the flash point, and the tank is not exposed to other tanks containing flammable Hquids. 

The areas for the reactors and storage tanks should be separated by fire walls, and must be adequately ventilated. Storage tanks should be blanketed by inert gas. A slight positive pressure of inert gas should be maintained in the reactor or storage tanks during the discharging of the resin or resin solution to prevent air from being sucked into the vessel to form an explosive mixture with the solvent vapor. 

Storage. Purified and dry aHyl chloride can be safely stored in carbon steel vessels. Use of lined vessels is recommended if slight discoloration or trace presence of metals is undesirable for its intended use. In any event, the presence of air should be avoided for safety (flammabHity) reasons through the use of an inert gas pad. Tank vents should be treated, eg, by incineration, prior to venting to the atmosphere. Some commercial producers intentionaHy add about 0.1% propylene oxide as a stabilizer to prevent discoloration however, this is usuaHy unnecessary if product purity is sufficiently high. 

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. 

Ethylene oxide storage tanks ate pressurized with inert gas to keep the vapor space in a nonexplosive region and prevent the potential for decomposition of the ethylene oxide vapor. The total pressure that should be maintained in a storage tank increases with Hquid temperature, since the partial pressure of ethylene oxide will also increase. Figure 5 shows the recommended minimum storage pressures for Hquid ethylene oxide under nitrogen or methane blanketing gas. 

Safe dilution requirements can be given for the gas phase in a flammability diagram or equation (270,273). Alternatively, safe vapor dilution can be given in terms of the Hquid storage conditions where allowance can be made for solubility of the inert gas in Hquid ethylene oxide (273). 

The handling of the monomer presents a number of problems. The monomer will polymerise on storage even under an inert gas. Polymer deposition may be observed after standing for less than a day. Exposure to air, to water or to light will accelerate polymerisation. A number of phenolic materials are effective inhibitors, a typical example being 0.02% p-methoxyphenol. Exposure to light, air and water must, however, still be avoided. The monomer has an anaesthetic action and chronic toxic properties and care must therefore be taken in its handling. 

The coke is taken to a quench tower, where it is cooled with a water spray or by circulating an inert gas (e.g., nitrogen), a process known as dry quenching. The coke is then screened and sent to a blast furnace or to storage. 

Storage tanks and surge vessels for MEA must have inert blanket-gas systems. Sweet natural gas or nitrogen can be used as the blanket gas. This is required because MEA will oxidize when exposed to the oxygen in air. 

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. 

Storage In air, in vacuum, in inert gas, refrigerated, frozen storage, transport... 

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