Makeup gas

Heating is usually accompHshed with a semiclosed loop which has a constant fresh gas makeup and a bleed to draw off the desorbed material. However, contaminant is at a higher level than in an open loop and product purity is harder to achieve. 

Eaeh reservoir eompartment should be provided with two three-quarter-ineh minimum size plugged eonneetions above the rundown oil level. These eonneetions may be used for sueh serviees as purge gas, makeup, oil supply, and elarifier return. One eonneetion should be strategieally loeated to ensure an effeetive sweep of purge gas toward the vents. 

The second indirect method is by measurement of the weight of ethylene oxide delivered from the feed containers to the sterilizer. This method assumes no leakage, liquefaction, or polymerization of ethylene oxide in the gas tines connecting the gas source to the sterilizer. It is recommended that the two indirect methods be used in conjunction with each other. The weight loss method ensures that the increase in pressure is in fact due to gas from the ethylene oxide feed container and not from diluent gas or some other source whereas the pressure method provides an ongoing index of gas concentration during the exposure period. Gas makeups should be automated and specified to be drawn from the ethylene oxide feed tanks, not from the diluent gas. Gas makeup may be controlled by pressure switches or by pressure transducers connected to solenoid valves controlling gas flow. 

Power cost contribution includes cost of gas makeup for leakage losses and 10% working capital against inventory. 

The synthesis gas makeup enters the loop upstream of the chilling system, is cooled down, and then mixed with the loop gas upstream of the ammonia separator. 

Chitosan-modified silica aerogek have also been tested for chemical catalysis applications, for example, in Ref. [122]. After impregnation of the aerogel with Pd salts and chemical reduction, the resulting model catalyst was tested for the selective hydrogenation of acetylene in the presence of ethylene and superior selectivity for acetylene was found. Such a catalyst system can find use in the gas makeup for polyolefine production (e.g., ethylene purification). Removal of acetylene is important as it is a catalyst poison for commonly used olefin polymerization catalysts. A high selectivity in such a gas makeup catalyst is essential, so that the precious ethylene itself is not hydrogenated. 

The following strategy closes isolation valves in an attempt to reduce the gas leakage rate, extending plant life. A spare Brayton unit would be started if available, and electrical loads would be shifted to it for continuity of electrical power. If a gas makeup system was provided, it would be utilized to restore gas mass and pressure within the Plant. However, the ability to successfully execute such a strategy requires three assumptions ... 

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