Inert gas blanket

Vapor Treatment. The vapors from the tank space can be sent to a treatment system (condenser, absorption, etc.) before venting. The system shown in Fig. 9.1 uses a vacuum-pressure relief valve which allows air in from the atmosphere when the liquid level falls (Fig. 9.1a) but forces the vapor through a treatment system when the tank is filled (Fig. 9.16). If inert gas blanketing is required, because of the flammable nature of the material, then a similar system can be adopted which draws inert gas rather than air when the liquid level falls. 

Waste facihties should be designed to prevent explosions in sewer systems and typically are comprised of suitable traps, vents, clean-outs, collecting chambers, etc. Flammable gas detectors are installed in sewers to warn of ha2ardous concentrations, and inert gas blanketing of closed process sumps generally is advisable. 

Fatty Acid Process. When free fatty acids are used instead of oil as the starting component, the alcoholysis step is avoided. AH of the ingredients can therefore be charged into the reactor to start a batch. The reactants are heated together, under agitation and an inert gas blanket, until the desired endpoint is reached. Alkyds prepared by the fatty acid process have narrower molecular weight distribution and give films with better dynamic mechanical properties (34). 

Internal pressure may be caused by several potential sources. One source is the vapor pressure of the Hquid itself. AH Hquids exert a characteristic vapor pressure which varies with temperature. As the temperature iacreases, the vapor pressure iacreases. Liquids that have a vapor pressure equal to atmospheric pressure boH. Another source of internal pressure is the presence of an iaert gas blanketing system. Inert gas blankets are used to pressuri2e the vapor space of a tank to perform speciali2ed functions, such as to keep oxygen out of reactive Hquids. The internal pressure is regulated by PV valves or regulators. 

For reactors containing flammable liquids, where the reactor design pressure is insufficient to contain a deflagration, consideration should be given to providing an inert gas blanket (usually nitrogen). 

Fieat activated device triggers CO2 or inert gas blanket... 

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)... 

Consideration shonld also be given to the possibility that the flame arrester may ping, which conld prodnce a vacnnm condition in a low-pressnre tank when the tank is primped out, and implode (collapse) the tank. This may reqnire the installation of a vacnnm breaker or a pressnre-vacnnm conservation valve. If the tank contents are flammable and admission of air may resnlt in an ignitable mixture, it may be necessary to install an inert gas blanketing system on the tank, actuated by a pressnre controller, which would admit a sufficient flow of inerting gas when a vacnnm condition is detected. 

Liquids are usually stored in bulk in vertical cylindrical steel tanks. Fixed and floating-roof tanks are used. In a floating-roof tank a movable piston floats on the surface of the liquid and is sealed to the tank walls. Floating-roof tanks are used to eliminate evaporation losses and, for flammable liquids, to obviate the need for inert gas blanketing to prevent an explosive mixture forming above the liquid, as would be the situation with a fixed-roof tank. 

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],... 

React overnight at room temperature. Maintain an inert-gas blanket over the vessel to prevent lipid oxidation. 

Carbon monoxide is a stable gas. Metal carbonyls are relatively unstable and sensitive to light and moderately high temperatures. They may spontaneously ignite on contact with air. Volatile agents are stored in steel cylinders otherwise, agents are stored in steel or glass containers. Metal carbonyls may be stored under an inert gas blanket, such as nitrogen, to prevent contact with the air. 

A number of benzo- or dibenzo-fused seven membered phosphorus heterocyclic systems have also been studied. These include the benzo-fused oxa-bridged phosphaalkene 76 prepared by thermolysis of 2,3-diphenylindenone 23-epoxide (as a source of the carbonyl ylide 1,3-dipole intermediate) in the presence of /-butylphosphaalkyne. This bridged phosphaalkene is unusually stable even without inert gas blanketing . Reaction of 76 with sulfur or grey selenium stereoselectively affords the thia- or selenaphosphiranes 77 (X = S, Se respectively). <00T6259>... 

Where process, safety, and environmental considerations permit, vacuum protection may be provided by properly sized ever-open vents. Alternatively, active protective devices and systems are required. Vacuum breaker valves designed to open and admit air at a predetermined vacuum in the vessel are commonly used on storage tanks, but may not be suitable for some applications involving flammable liquids. Inert gas blanketing systems may be used if adequate capacity and reliability can be ensured. Where the source of the vacuum can be deenergized or isolated, suitably reliable safety instrumented systems (e.g, interlocks) can be provided. 

Owing to their liquid or semisolid nature, monomers are easy to process into polymers. For radical polymerization the use of solid AIBN for liquid monomers at room temperature and liquid MEKP for semisolid monomers or a mixture of liquid and semisolid monomers with some heating is convenient. During the course of curing at 85- 100°C for 22 h the problem of surface inhibition of free radicals by oxygen from the air can be avoided by inert-gas blanketing. 

A final aspect of GPC solvent delivery relates to the solvent reservoirs themselves. The ability to perform in situ helium degassing of solvents, provide inert gas blankets over solvents, and protect solvents from contamination from external sources are worth consideration from the standpoints of convenience and safety alone. If these features are provided for, it is a small step to also provide a small positive pressure, say 10 psi or so, to the solvent reservoir. This positive pressure helps minimize the formation of solvent vapors in the pump chamber during the refill part of the pump stroke, and improves the flow rate reproducibility of rapid-refill type pumps delivering high-vapor-pressure solvents. 

Fig. 3.3. If a pressure by-pass is used without either an inert-gas blanket or a PTFE tap, distillation of the solvent from the reactor into the burette (or vice versa) may occur.

The whole procedure can be done on a vacuum line, but is certainly easier and swifter in the open if done on the bench , one must take precautions against the acid (or indeed any other liquid) picking up atmospheric moisture during the processing. (Inert gas blanket or dry-box, p. 5)... 

Conditioning of the Product. The high porosity and low moisture content of the freeze-dried product require that the vacuum be broken and packaging he done under a dried inert-gas blanket, in many cases, to prevent oxidation during storage and maintain the low moisture content. Carbon dioxide or nitrogen are commonly used. 

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