High-pressure nitrogen injection

High-pressure nitrogen injection is considered an EOR process (Manrique et al., 2007). Some authors (e.g., Moritis, 2000) classify iimniscible gas injection as EOR too. In those cases, processes other than pressure maintenance are involved, and the processes result in more oil recovered. 

Compressed gases—Most common gases used are nitrogen, air and carbon dioxide. These gases are dissolved under pressure in the resin and produce foam upon release of the pressure. The use of nitrogen in injection-molded foam products is typical. The nitrogen is injected under high pressure. When the pressure is relieved the gas becomes less soluble in the polymer and forms cells. 

Reactions in RC Ionization is initiated by formation of alkah-metal ions on the emitter. A successful method for obtaining lithium ion cationization mass spectra must provide a means for binding hthium ion to the sample molecules. Lithium ions can be injected into an inert gas, such as nitrogen, that contains a trace amormt of sample, and (M + Li)+ complexes are formed by termolecnlar association reactions. The ionic products observed are a reflection of association reaction rates. The formation of an adduct ion is commonly assumed to be a three-body process, in which a neutral molecule collides with an ion-molecule complex and removes an amormt of energy, stabilizing the (M + Li)+ complex. Based on this model, the cationization process would be suitable in a high-pressure environment, since the added gas molecules serve as the third body in the analyte addition reaction with alkali-metal ions. 

In order to create a cavity, nitrogen is injected into the melted polymer at high pressure (typically between 80 and 350 bar). The gas forces the polymer towards the walls of the mould, creating the hollow section. After the plastic has solidified, the nitrogen is released from the cavity. 

Fig. 2.27 Diagram of a GIM installation Combined with a high-pressure evaporator, Desy is a practical nitrogen supply system for gas-assisted injection moulding (GIM).

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