Nitrogen generator refers to air- to- nitrogen production complex that might be either stationary or a mobile unit. Absorption concept is applied here for the absorption gas separation process, which is based on the phenomenon of fixing various gas mixture components called absorbent, which is a solid substance
The pressure swing adsorption technology
The nitrogen generators are being operated on the principle of the dependence of the absorption rates featured by various gas mixture components in relation to pressure and temperature factors which is the key principle of absorption technology. This technology of air to nitrogen production by using absorption pressure in nitrogen generator is widely used in industrial facilities as it is well studied by the researchers. And all over the world, the pressure swing adsorption plants (PSA) are found to have the broadest application amongst various types of nitrogen absorption plants.
There are two absorber- absorbent- containing vessels where pressures are changed for gas absorption and absorbent generation in the design of the system. The process requires constant temperature almost close to ambient. In the plant, nitrogen is being produced at the above- atmospheric pressure in this process and the absorbent generation is done at below- atmospheric pressure.
There are two stages in the swing adsorption process in both of the absorbers which run for a few minutes. At the stage of absorption, the nitrogen molecules are allowed to pass through the absorber- absorbent- containing vessel while oxygen, carbon dioxide, and water molecules are diffused into the pore structure of the absorbent. At the stage of generation, absorb components that are released from the absorbent are vented into the atmosphere.after that the process is being repeated for multiple times.
The advantages of the nitrogen generator
- PSA nitrogen generator plants produce high purity nitrogen which is up to 99.9995% nitrogen, from the air which is not possible from the membrane systems.
- Although in most of the cases, 98.8% nitrogen is produced with argon being the remainder which is not separated by the usual PSA process from nitrogen. Since argon is more inert than nitrogen, it does not cause any problem normally. In the cryogenic system, pure nitrogen can also be produced. But the system is much more complex and only be justified while being produced in large volume. The nitrogen generators use carbon molecular sieve (CMS) to ensure a continuous supply of high purity nitrogen available with or without internal compressors.
- The operating cost of nitrogen generator is quite low in comparison to out-of-date air separation plants. It does save more than 50% of the production cost. Therefore it can easily be imagined how much it is cheaper than bottled or liquefied nitrogen.
The production of nitrogen with nitrogen generator is much more environmental friendly. It is absolutely an energy efficient process to ensure clean, pure and dry nitrogen gas. Generated nitrogen requires much less energy and produces far fewer greenhouse gases in comparison to cryogenic air separation plant and the energy required for the transport of liquid nitrogen from the plant to the facility.