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Gas separation can refer to any of a number of techniques used to separate gases, either to give multiple products or to purify a single product. Swing adsorption techniques [ edit ]
VSA typically draws the gas through the separation process with a vacuum. For oxygen and nitrogen VSA systems, the vacuum is typically generated by a blower. Hybrid vacuum pressure swing adsorption (VPSA) systems also exist. VPSA systems apply pressurized gas to the separation process and also apply a vacuum to the purge gas.
This process requires constant temperature, close to ambient. With this process, nitrogen is produced by the plant at the above-atmospheric pressure, while the adsorbent regeneration is accomplished at below-atmospheric pressure. The swing adsorption process in each of the two adsorbers consists of two stages running for a few minutes.
A nitrogen generator Bottle of 4Å molecular sieves. Pressure swing adsorption provides separation of oxygen or nitrogen from air without liquefaction. The process operates around ambient temperature; a zeolite (molecular sponge) is exposed to high pressure air, then the air is released and an adsorbed film of the desired gas is released.
The dealumination process is done by treating the zeolite with steam at elevated temperatures, typically greater than 500 °C (930 °F). This high temperature heat treatment breaks the aluminum-oxygen bonds and the aluminum atom is expelled from the zeolite framework.
The amount of adsorbed gas depends on pressure, temperature and adsorbent type. Since this adsorption process is exothermic, an increase in pressure or a decrease in temperature enhances the efficiency of the adsorption process. It is possible to mix the ANG and CNG technology to reach an increased capacity of natural gas storage.
The adsorption sites (heavy dots) are equivalent and can have unit occupancy. Also, the adsorbates are immobile on the surface. The Langmuir adsorption model explains adsorption by assuming an adsorbate behaves as an ideal gas at isothermal conditions. According to the model, adsorption and desorption are reversible processes.
Also, two primary or secondary amine molecules are generally required to absorb a single CO 2 molecule in liquids. For solid surfaces, large capacities of CO 2 can be adsorbed. For temperature swing adsorption processes, the lower heat capacity of solids has been reported to reduce the sensible energy required for sorbent regeneration. [9]