Pressure swing adsorption (PSA) nitrogen production technology

When you are producing nitrogen yourself, it is very important how much pure nitrogen you make yourself. Some applications require low purity (between 90 - 99%), such as tire inflation and fire protection, while others, such as the food and beverage industry or plastic molding, require high purity (from 97 to 99.999%). In these cases, PSA technology is the most ideal and easiest method.

Essentially, a nitrogen generator works by separating nitrogen from oxygen in compressed air. Pressure swing adsorption works by capturing oxygen from compressed air by adsorption. Adsorption occurs when the molecules bind to the adsorbent, where oxygen molecules are attached to carbon molecular sieves (CMS). This happens in two separate pressure vessels, each filled with CMS, switching between the separation process and the regeneration process. We call them Tower A and Tower B.

First, clean and dry compressed air enters tower A, and since oxygen molecules are smaller than nitrogen molecules, they will enter the pores of the carbon sieve. Nitrogen molecules, on the other hand, cannot enter the pores, so they bypass the carbon molecular sieve. You end up with nitrogen of ideal purity. This stage is called the adsorption or separation stage.

However, it didn't stop there. Most of the nitrogen produced in column A is removed from the system (ready for immediate use or storage), while a small portion of the nitrogen produced goes into column B in the opposite direction (top to bottom). This flow requires the removal of oxygen that was previously adsorbed on the B column. By releasing the pressure inside the B tower, the carbon molecular sieve loses its ability to adsorb oxygen. They are separated from the sieve and carried away by the nitrogen discharged from the a tower. This way, the system makes room for new oxygen molecules attached to the sieve in the next adsorption stage. We call this "purification" process "saturated oxygen tower regeneration".